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Sample records for agricultural catchments programme

  1. Agricultural Catchments: Evaluating Policies and Monitoring Adaptive Management

    NASA Astrophysics Data System (ADS)

    Jordan, P.; Shortle, G.; Mellander, P. E.; Shore, M.; McDonald, N.; Buckley, C.

    2014-12-01

    Agricultural management in river catchments must combine the objectives of economic profit and environmental stewardship and, in many countries, mitigate the decline of water quality and/or maintain high water quality. Achieving these objectives is, amongst other activities, in the remit of 'sustainable intensification'. Of concern is the efficient use of crop nutrients, phosphorus and nitrogen, and minimising or offsetting the effects of transfers from land to water - corner-stone requirements of many agri-environmental regulations. This requires a robust monitoring programme that can audit the stages of nutrient inputs and outputs in river catchments and indicate where the likely points of successful policy interventions can be observed - or confounded. In this paper, a catchment, or watershed, experimental design and results are described for monitoring the nutrient transfer continuum in the Irish agricultural landscape against the backdrop of the European Union Nitrates and Water Framework Directives. This Agricultural Catchments Programme experimental design also serves to indicate water quality pressure-points that may be catchment specific as agricultural activities intensify to adapt to national efforts to build important parts of the post-recession economy.

  2. Environmental care in agricultural catchments: Toward the communicative catchment

    NASA Astrophysics Data System (ADS)

    Martin, Peter

    1991-11-01

    Substantial land degradation of agricultural catchments in Australia has resulted from the importation of European farming methods and the large-scale clearing of land. Rural communities are now being encouraged by government to take responsibility for environmental care. The importance of community involvement is supported by the view that environmental problems are a function of interactions between people and their environment. It is suggested that the commonly held view that community groups cannot care for their resources is due to inappropriate social institutions rather that any inherent disability in people. The communicative catchment is developed as a vision for environmental care into the future. This concept emerges from a critique of resource management through the catchment metaphors of the reduced, mechanical, and the complex, evolving catchment, which reflect the development of systemic and people-centered approaches to environmental care. The communicative catchment is one where both community and resource managers participate collaboratively in environmental care. A methodology based on action research and systemic thinking (systemic action research) is proposed as a way of moving towards the communicative catchment of the future. Action research is a way of taking action in organizations and communities that is participative and informed by theory, while systemic thinking takes into account the interconnections and relationships between social and natural worlds. The proposed vision, methodology, and practical operating principles stem from involvement in an action research project looking at extension strategies for the implementation of total catchment management in the Hunter Valley, New South Wales.

  3. Grey water on three agricultural catchments in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Blazkova, Sarka D.; Kulasova, Alena

    2014-05-01

    The COST project EU EURO-AGRIWAT focuses apart from other problems on the assessment of water footprint (WF). WF is defined as the quantity of water used to produce some goods or a service. In particular, the WF of an agricultural product is the volume of water used during the crop growing period. It has three components: the green water which is rain or soil moisture transpired by a crop, the blue water which is the amount of irrigation water transpired and the grey water which is the volume of water required to dilute pollutants and to restore the quality standards of the water body. We have been observing three different agricultural catchments. The first of them is Smrzovka Brook, located in the protected nature area in the south part of the Jizerske Mountains. An ecological farming has been carried out there. The second agricultural catchment area is the Kralovsky Creek, which lies in the foothills of the Krkonose Mountains and is a part of an agricultural cooperative. The last agricultural catchment is the Klejnarka stream, located on the outskirts of the fertile Elbe lowlands near Caslav. Catchments Kralovsky Brook and Klejnarka carry out usual agricultural activities. On all three catchments, however, recreational cottages or houses not connected to the sewerage system and/or with inefficient septic tanks occur. The contribution shows our approach to trying to quantify the real grey water from agriculture, i.e. the grey water caused by nutrients not utilised by the crops.

  4. Characterising groundwater-dominated lowland catchments: the UK Lowland Catchment Research Programme (LOCAR)

    NASA Astrophysics Data System (ADS)

    Wheater, H. S.; Peach, D.; Binley, A.

    2007-01-01

    This paper reports on a major UK initiative to address deficiencies in understanding the hydro-ecological response of groundwater-dominated lowland catchments. The scope and objectives of this national programme are introduced and focus on one of three sets of research basins - the Pang/Lambourn Chalk catchments, tributaries of the river Thames in southern England. The motivation for the research is the need to support integrated management of river systems that have high ecological value and are subject to pressures that include groundwater abstraction for water supply, diffuse pollution, and land use and climate change. An overview of the research programme is provided together with highlights of some current research findings concerning the hydrological functioning of these catchments. Despite the importance of the Chalk as a major UK aquifer, knowledge of the subsurface movement of water and solutes is poor. Solute transport in the dual porosity unsaturated zone depends on fracture/matrix interactions that are difficult to observe; current experimental and modelling research supports the predominance of matrix flow and suggests that slow migration of a time-history of decades of nutrient loading is occurring. Groundwater flows are complex; catchments vary seasonally and are ill-defined and karst features are locally important. Groundwater flow pathways are being investigated using natural and artificial geochemical tracers based on experimental borehole arrays; stream-aquifer interaction research is using a combination of geophysics, borehole array geochemistry and longitudinal profiles of stream flow and solutes. A complex picture of localised subsurface inflows, linked to geological controls and karst features, and significant longitudinal groundwater flow below the river channel is emerging. Management implications are discussed. Strategies to control surface application of nutrients are expected to have little effect on groundwater quality for several

  5. Phosphorus delivery via groundwater in agricultural river catchments

    NASA Astrophysics Data System (ADS)

    Mellander, Per-Erik; Jordan, Philip; Shore, Mairead; Melland, Alice R.

    2014-05-01

    Mitigating diffuse phosphorus (P) delivery to rivers, lakes and estuaries in the agricultural landscape is important for ecological quality management. In order to plan this management, it is useful to identify and quantify dominating P transfer pathways and their potential variation over time and space. Phosphorus is anticipated to mainly be transferred to rivers episodically via pathways on the surface and is not usually considered as a major concern in groundwater-fed waters. However, in this paper we report considerable proportions of P delivery via groundwater in two agricultural river catchments with permeable soils. We investigated the P transfer pathways and links between groundwater and surface water, as well as the implication of spatio-temporally variable P concentrations in groundwater at the hillslope scale. We present four years of P concentrations in stream water (sub-hourly) and in groundwater (monthly) of different strata in four hillslopes, as well as estimated P transfer pathways for winter periods (Oct-Jan) in two ca. 10 km2 catchments in Ireland. One catchment was dominated by arable land overlying slate bedrock and the other by grassland overlying sandstone. High temporal resolution monitoring of river discharge and P concentration allowed an estimation of total P (TP) and total reactive P (TRP) transfer pathways as well as flow pathways. In the groundwater of both catchments the 4-year average dissolved reactive P was up to 0.021 mg/l (Arable) and 0.050 mg/l (Grassland) in shallow near-stream groundwater. During the winter periods in the Arable catchment 20% of the runoff, 59% of stream TP load and 35% of stream TRP load was transferred by quick aboveground pathways while 77% of runoff, 36% of TP and 58% of TRP was transferred via delayed groundwater pathways. In the Grassland catchment 10% of the runoff, 48% of TP and 38% of TRP was transferred above ground while 86% of runoff, 46% of TP and 55% of TRP transferred via groundwater. In both

  6. Seasonal Variations of Nitrate Concentrations In Agricultural Catchments

    NASA Astrophysics Data System (ADS)

    Martin, C.; Aquilina, L.; Gascuel-Odoux, C.; Molénat, J.; Ruiz, L.

    Nitrate concentrations in streams of agricultural catchments with impervious bedrock often present an interannual variability (due to landuse changes) and a seasonal one. Usually seasonal variations are characterised by high concentrations in winter and low in summer. Some catchments may present intermediate or inverse cycles (high con- centrations in summer). Two hypothesis to explain classical variations of nitrate con- centrations in streams exist: (i) the availibility of nitrate in the soil for leaching and (ii) the temporal variations of the nitrate-rich shallow groundwater. The aim of this study is to explain the occurence of classical or inverse scheme of seasonal variations by testing these two existing hypothesis and proposing an alternative one for inverse cycles. Two catchments with different seasonal variations (KERRIEN catchment : normal cycle, and KERBERNEZ catchment : inverse cycle), located in the South Western French Brittany, were instrumented in 2001 with a set of 22 piezometers in- stalled at different depths and located along the hillslope. The water table dynamic and chemestry (nitrate, chloride, carbon, Rare Earth Elements,...) had been measured weekly during one year. The shallow groundwater of the Kerrien catchment is char- acterised by two lateral domains with a temporal stability of concentrations : the bot- tom land, constantly denitrified, and the upper domain with nitrate concentrations around 60 mg.L(-1) . The Kerbernez catchment is characterised by two vertical domains with a temporal rise of concentrations : the upper domain with nitrate concen- trations around 60 mg.L(-1) , as the Kerrien catchment, and a deeper compartment, with concentrations excedeed 100 to 120 mg.L(-1) of nitrate. On the Kerrien catchment, the classical cycle is due to the most important contribution of the shal- low groundwater in winter. The inverse cycle of the Kerbernez catchment may be due to the most important contribution of the deep compartment in

  7. Patterns and processes of nutrient transfers from land to water: a catchment approach to evaluate Good Agricultural Practice in Ireland

    NASA Astrophysics Data System (ADS)

    Mellander, P.-E.; Melland, A. R.; Shortle, G.; Wall, D.; Mechan, S.; Buckley, C.; Fealy, R.; Jordan, P.

    2009-04-01

    Eutrophication of fresh, transitional and coastal waters by excessive nutrient inputs is one of the most widespread water quality problems in developed countries. Sources of nutrient nitrogen (N) and phosphorus (P) can come from a multiplicity of sources and be dependent on numerous hydrological controls from catchments with both urban and agricultural landuses. Aquatic impacts are widely reported as a result of excessive nutrient transfers from land to water and include changes in ecological integrity and loss of amenity. In the European Union, the Water Framework Directive (WFD) and associated Directives are the key structures with which member states must develop national and often trans-national polices to deal with issues of water resources management. The linked Nitrates Directive is particularly concerned with integrating sustainable agriculture and good water quality objectives and is written into national polices. In Ireland this policy is the Nitrates Directive National Action Programme (NAP), Statutory Instruction 378, Good Agricultural Practise regulation, and amongst other things, sets targets and limits on the use of organic and inorganic fertilisers, soil fertility and slurry/fertiliser spreading and cultivation times. To evaluate the effectiveness of this policy, Teagasc, the Irish Agriculture and Food Development Authority, is undertaking a catchment scale audit on sources, sinks, and changes in nutrient use and export over several years. The Agricultural Catchments Programme is based on a science-stakeholder-management partnership to generate knowledge and specifically to protect water quality from nitrogen and phosphorus transfers within the constraints of the requirements of modern Irish agricultural practises. Eight catchments of 5-12 km2 have been selected for the programme to represent a range of agricultural intensities and vulnerabilities to nitrogen and phosphorus loss including catchments that are situated on permeable and impermeable

  8. Hydrological Controls on Nutrient Concentrations and Fluxes in Agricultural Catchments

    NASA Astrophysics Data System (ADS)

    Petry, J.; Soulsby, C.

    2002-12-01

    This investigation into diffuse agricultural pollution and the hydrological controls that exert a strong influence on both nutrient concentrations and fluxes, was conducted in an intensively farmed lowland catchment in north-east Scotland. The study focuses on spatial and seasonal variations in nutrient concentrations and fluxes at the catchment scale, over a 15-month period. The water quality of the 14.5 km2 Newmills Burn catchment has relatively high nutrient levels with mean concentrations of NO3-N and NH3-N at 6.09 mg/l and 0.28 mg/l respectively. Average PO4-P concentrations are 0.06 mg/l. Over short timescales nutrient concentrations and fluxes are greatest during storm events when PO4-P and NH3-N are mobilised by overland flow in riparian areas, where soils have been compacted by livestock or machinery. Delivery of deeper soil water in subsurface storm flow, facilitated by agricultural under-drainage, produces a marked increase in NO3-N (6.9 mg/l) concentrations on the hydrograph recession limb. A more detailed insight into the catchment response to storm events, and in particular the response of the hydrological pathways which provide the main sources of runoff during storm events, was gained by sampling stream water at 2-hourly intervals during 5 events. End Member Mixing Analysis (EMMA) was carried out using event specific end-member chemistries to differentiate three catchment-scale hydrological pathways (overland flow, subsurface storm flow, groundwater flow) on the basis of observed Si and NO3-N concentrations in sampled source waters. Results show that overland flow generally dominates the storm peak and provides the main flow path by which P is transferred to stream channels during storm events, whilst subsurface storm flows usually dominate the storm hydrograph volumetrically and route NO3-rich soil water to the stream. The study shows that altering hydrological pathways in a catchment can have implications for nutrient management. Whilst buffer

  9. Nitrogen attenuation along delivery pathways in agricultural catchments

    NASA Astrophysics Data System (ADS)

    McAleer, Eoin; Mellander, Per-Erik; Coxon, Catherine; Richards, Karl G.

    2014-05-01

    Hillslope hydrologic systems and in particular near-stream saturated zones are active sites of nitrogen (N) biogeochemical dynamics. The efficiency of N removal and the ratio of reaction products (nitrous oxide and dinitrogen) in groundwater is highly variable and depends upon aquifer hydrology, mineralogy, dissolved oxygen, energy sources and redox chemistry. There are large uncertainties in the closing of N budgets in agricultural catchments. Spatial and temporal variability in groundwater physico-chemistry, catchment hydrology and land-use gives rise to hotspots and hot moments of N attenuation. In addition the production, consumption and movement of denitrification products remains poorly understood. The focus of this study is to develop a holistic understanding of N dynamics in groundwater as it moves from the top of the hillslope to the stream. This includes saturated groundwater flow, exchange at the groundwater-surface water interface and hyporheic zone flow. This project is being undertaken in two ca. 10km2 Irish catchments, characterised by permeable soils. One catchment is dominated by arable land overlying slate bedrock and the other by grassland overlying sandstone. Multi-level monitoring wells have been installed at the upslope, midslope and bottom of each hillslope. The piezometers are screened to intercept the subsoil, weathered bedrock and competent bedrock zones. Groundwater samples for nitrate (NO3-N) nitrite (NO2-N), ammonium (NH4-N) and total nitrogen are collected on a monthly basis while dissolved gas concentrations are collected seasonally. Groundwater NO3-N profiles from monitoring data to date in both catchments differ markedly. Although the two catchments had similar 3 year mean concentrations of 6.89 mg/L (arable) and 6.24 mg/L (grassland), the grassland catchment had higher spatial and temporal variation. The arable catchment showed relatively homogenous NO3-N concentrations in all layers and zones (range: 1.2 - 12.13 mg/L, SD = 1.60 mg

  10. Tracing crop-specific sediment sources in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Blake, William H.; Ficken, Katherine J.; Taylor, Philip; Russell, Mark A.; Walling, Desmond E.

    2012-02-01

    A Compound Specific Stable Isotope (CSSI) sediment tracing approach is evaluated for the first time in an agricultural catchment setting against established geochemical fingerprinting techniques. The work demonstrates that novel CSSI techniques have the potential to provide important support for soil resource management policies and inform sediment risk assessment for the protection of aquatic habitats and water resources. Analysis of soil material from a range of crop covers in a mixed land-use agricultural catchment shows that the carbon CSSI signatures of particle-reactive fatty acids label surface agricultural soil with distinct crop-specific signatures, thus permitting sediment eroded from each land-cover to be tracked downstream. High resolution sediment sampling during a storm event and analysis for CSSI and conventional geochemical fingerprints elucidated temporal patterns of sediment mobilisation under different crop regimes and the specific contribution that each crop type makes to downstream sediment load. Pasture sources (65% of the catchment area) dominated the sediment load but areal yield (0.13 ± 0.02 t ha - 1 ) was considerably less than that for winter wheat (0.44 ± 0.15 t ha - 1 ). While temporal patterns in crop response matched runoff and erosion response predictions based on plot-scale rainfall simulation experiments, comparison of biomarker and geochemical fingerprinting data indicated that the latter overestimated cultivated land inputs to catchment sediment yield due to inability to discriminate temporary pasture (in rotation) from cultivated land. This discrepancy, however, presents an opportunity since combination of the two datasets revealed the extremely localised nature of erosion from permanent pasture fields in this system (estimated at up to 0.5 t ha - 1 ). The novel use of CSSI and geochemical tracers in tandem provided unique insights into sediment source dynamics that could not have been derived from each method alone. Research

  11. Identification of phosphorus emission hotspots in agricultural catchments

    PubMed Central

    Kovacs, Adam; Honti, Mark; Zessner, Matthias; Eder, Alexander; Clement, Adrienne; Blöschl, Günter

    2012-01-01

    An enhanced transport-based management approach is presented, which is able to support cost-effective water quality management with respect to diffuse phosphorus pollution. Suspended solids and particulate phosphorus emissions and their transport were modeled in two hilly agricultural watersheds (Wulka River in Austria and Zala River in Hungary) with an improved version of the catchment-scale PhosFate model. Source and transmission areas were ranked by an optimization method in order to provide a priority list of the areas of economically efficient (optimal) management alternatives. The model was calibrated and validated at different gauges and for various years. The spatial distribution of the emissions shows that approximately one third of the catchment area is responsible for the majority of the emissions. However, only a few percent of the source areas can transport fluxes to the catchment outlet. These effective source areas, together with the main transmission areas are potential candidates for improved management practices. In accordance with the critical area concept, it was shown that intervention with better management practices on a properly selected small proportion of the total area (1–3%) is sufficient to reach a remarkable improvement in water quality. If soil nutrient management is also considered in addition to water quality, intervention on 4–12% of the catchment areas can fulfill both aspects. PMID:22771465

  12. Influence of teleconnection on water quality in agricultural river catchments

    NASA Astrophysics Data System (ADS)

    Mellander, Per-Erik; Jordan, Phil; Shore, Mairead; McDonald, Noeleen; Shortle, Ger

    2015-04-01

    Influences such as weather, flow controls and lag time play an important role in the processes influencing the water quality of agricultural catchments. In particular weather signals need to be clearly considered when interpreting the effectiveness of current measures for reducing nitrogen (N) and phosphorus (P) losses from agricultural sources to water bodies. In north-western Europe weather patterns and trends are influenced by large-scale systems such as the North Atlantic Oscillation (NAO) and the position of the Gulf Stream, the latter expressed as the Gulf Stream North Wall index (GSNW index). Here we present five years of monthly data of nitrate-N concentration in stream water and groundwater (aggregated from sub-hourly monitoring in the stream outlet and monthly sampling in multilevel monitoring wells) from four agricultural catchments (ca. 10 km2) together with monitored weather parameters, long-term weather data and the GSNW index. The catchments are situated in Ireland on the Atlantic seaboard and are susceptible to sudden and seasonal shifts in oceanic climate patterns. Rain anomalies and soil moisture deficit dynamics were similar to the dynamics of the GSNW index. There were monitored changes in nitrate-N concentration in both groundwater and surface water with no apparent connection to agricultural management; instead such changes also appeared to follow the GSNW index. For example, in catchments with poorly drained soils and a 'flashy hydrology' there were seasonal dynamics in nitrate-N concentration that correlated with the seasonal dynamics of the GSNW index. In a groundwater driven catchment there was a consistent increase in nitrate-N concentration over the monitored period which may be the result of increasingly more recharge in summer and autumn (as indicated by more flux in the GSNW index). The results highlight that the position of the Gulf Stream may influence the nitrate-N concentration in groundwater and stream water and there is a risk

  13. Transport and attenuation of chloroacetanilides in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Lefrancq, Marie; Imfeld, Gwenaël; Millet, Maurice; Payraudeau, Sylvain

    2015-04-01

    Chloroacetanilides (e.g., S-metolachlor and acetochlor) are pre-emergent herbicides used on corn and sugar beet and are applied to bare soil, which is prone to runoff and erosion. Some of these herbicides are chiral and the commercial products can be isomerically enriched in the enantiomer-S compared to the enantiomer-R as an example S-metolachlor 80/20% S to R . Determination of the transport of these herbicides in the dissolved and particulate phases of runoff water and degradation in agricultural catchments is currently lacking. The objectives of this study were i) to quantify over an corn growing season the export of chloroacetanilides and their main degradation products (ethane sulfonic (ESA) and oxanilic acid (OXA) degradates of metolachlor (MESA and MOXA) and acetochlor (AcESA and AcOXA)) in an 47 ha agricultural head-catchment in the dissolved and particulate phases, and ii) to evaluate S-metolachlor biodegradation from its application on the field to its export from the catchment using enantiomer analysis. Runoff, erosion, hydrochemistry and chloroacetanilide transport were evaluated at both the plot and catchment scales. Our results showed that an important amount of the pesticide load is missed when only the dissolved concentration of the parent compound is analysed. The total export coefficients for S-metolachlor and acetochlor and their degradation products were 11.4 and 11.8%, respectively, which includes both the dissolved and particulate loads. The partitioning of S-metolachlor and acetochlor between the dissolved and particulate phases varied widely over time and was linked to the suspended solid concentrations. Detection of S-metolachlor degradation products in runoff water was more frequent compared to that of acetochlor degradation products. Enrichment up to 37% of R-metolachlor was observed during the corn growing season, supporting enantioselective degradation of S-metolachlor. Our field study indicates the potential of enantiomer analyses for

  14. Patterns and processes of nutrient transfers from land to water: a catchment approach to evaluate Good Agricultural Practice in Ireland

    NASA Astrophysics Data System (ADS)

    Mellander, P.-E.; Melland, A. R.; Shortle, G.; Wall, D.; Mechan, S.; Buckley, C.; Fealy, R.; Jordan, P.

    2009-04-01

    Eutrophication of fresh, transitional and coastal waters by excessive nutrient inputs is one of the most widespread water quality problems in developed countries. Sources of nutrient nitrogen (N) and phosphorus (P) can come from a multiplicity of sources and be dependent on numerous hydrological controls from catchments with both urban and agricultural landuses. Aquatic impacts are widely reported as a result of excessive nutrient transfers from land to water and include changes in ecological integrity and loss of amenity. In the European Union, the Water Framework Directive (WFD) and associated Directives are the key structures with which member states must develop national and often trans-national polices to deal with issues of water resources management. The linked Nitrates Directive is particularly concerned with integrating sustainable agriculture and good water quality objectives and is written into national polices. In Ireland this policy is the Nitrates Directive National Action Programme (NAP), Statutory Instruction 378, Good Agricultural Practise regulation, and amongst other things, sets targets and limits on the use of organic and inorganic fertilisers, soil fertility and slurry/fertiliser spreading and cultivation times. To evaluate the effectiveness of this policy, Teagasc, the Irish Agriculture and Food Development Authority, is undertaking a catchment scale audit on sources, sinks, and changes in nutrient use and export over several years. The Agricultural Catchments Programme is based on a science-stakeholder-management partnership to generate knowledge and specifically to protect water quality from nitrogen and phosphorus transfers within the constraints of the requirements of modern Irish agricultural practises. Eight catchments of 5-12 km2 have been selected for the programme to represent a range of agricultural intensities and vulnerabilities to nitrogen and phosphorus loss including catchments that are situated on permeable and impermeable

  15. Rainfall Threshold For Slope-Channel Connectivity In Agricultural Catchment

    NASA Astrophysics Data System (ADS)

    Święchowicz, Jolanta

    2015-04-01

    Many rainfall events lead to the transfer of soil material from one slope section to another, which does not notably alter slope relief (first transfer threshold). Some events lead to the transfer of soil from the water divide to the footslope (second transfer threshold). In a few exceptional cases, soil material is transferred directly into river channels due to severe erosion moving large quantities of soil over long distances. Extreme events lead to the transfer of soil material down the entire slope length, its deposition at the footslope and even further across the valley floor. Sediment is transferred directly from slopes to river channels (third transfer threshold or slope-channel connectivity threshold). This work presents rainfall threshold values and probability of slope-to-river sediment transfer in a foothill agricultural catchment in Poland. The study is based on research performed in the Dworski Potok Catchment (227-275 m a.s.l.), which is a small agricultural foothill catchment (0.29 km2), situated in a moderate climate zone, with slopes covered with loess-like formations. The paper uses precipitation data for the period 1987-2009 obtained at the Łazy Field Research Station near Bochnia (Poland) and long-term field data on splash (2007-2009), slope wash (2007-2009) and linear erosion (1998-2009) on slopes. In Dworski Potok Catchment change in the slope relief was brought about by short transformation periods, during which soil erosion by water took place, especially if it was caused by events of high magnitude and low frequency. Those periods which, depending on the criterion adopted, lasted from 0.3 to 4% of the time of study were the most interesting and effective episodes in the development of slopes. It was determined that in the researched multi-year period, the transfer of soil material was possible to occur after certain parameters had exceeded the following threshold values: EI30 = 40.5 MJmmha-1h-1 or I30 = 9.8 mmh-1 for the first transfer

  16. Response of current phosphorus mitigation measures across the nutrient transfer continuum in two hydrological contrasting agricultural catchments

    NASA Astrophysics Data System (ADS)

    McDonald, Noeleen; Shore, Mairead; Mellander, Per-Erik; Shortle, Ger; Jordan, Phil

    2015-04-01

    Effective assessment of National Action Programme (NAP) measures introduced under the EU Nitrates Directive (ND), to manage nutrient use and risk of loss to waters from agriculture, is best achieved when examined across the nutrient transfer continuum at catchment scale. The Irish NAP measures are implemented on a whole-territory basis for both nitrogen (N) and phosphorus (P), with P being the key trophic pressure. The aim of this research was to observe the efficacy of P regulation measures and P source management across the transfer continuum and resultant water quality status (i.e. source to impact), in two contrasting agricultural catchments over a four year period. The catchments are ca. 11 km2 and are located in the south-east of Ireland. One is well-drained and arable dominated, while the other is mostly poorly-drained and grassland dominated. In 2009 and 2013 soil surveys for plant-available P were carried out (<2 ha sample areas) in both catchments. Concurrently, high temporal resolution monitoring of water discharge and P concentration was conducted at each catchment outlet across four hydrological years (April to March). Ecological impact surveys were carried out at four sites within each catchment in May and September across the observed four year period (2009-2013). Importantly, the proportion of farmland with excessive soil P concentrations decreased in both the arable (20% to 11.8%) and grassland catchments (5.9 to 3.6%). However, soil P concentrations also declined critically in both catchments, as proportional areas below the national crop agronomic optimum thresholds (grassland; <5 mg P l-1, arable; <6 mg P l-1) increased from 57% to 68% in the arable catchment and 75% to 87% in the grassland catchment. This decline in plant available P strongly indicates a reduced or sustained level of P inputs in both catchments. Indications of responses to soil P change in the surface waters of these catchments appeared to be highly influenced by their

  17. Water Framework Directive catchment planning: a case study apportioning loads and assessing environmental benefits of programme of measures.

    PubMed

    Crabtree, Bob; Kelly, Sarah; Green, Hannah; Squibbs, Graham; Mitchell, Gordon

    2009-01-01

    Complying with proposed Water Framework Directive (WFD) water quality standards for 'good ecological status' in England and Wales potentially requires a range of Programmes of Measures (PoMs) to control point and diffuse sources of pollution. There is an urgent need to define the benefits and costs of a range of potential PoMs. Water quality modelling can be used to understand where the greatest impact in a catchment can be achieved through 'end of pipe' and diffuse source reductions. This information can be used to guide cost-effective investment by private water companies and those with responsibilities for agricultural, industrial and urban diffuse inputs. In the UK, river water quality modelling with the Environment Agency SIMCAT model is regarded as the best current approach to support decision making for river water quality management and planning. The paper describes how a SIMCAT model has been used to conduct a trial WFD integrated catchment planning study for the River Ribble catchment in the North West of England. The model has been used to assess over 80 catchment planning scenarios. The results are being used support a national assessment of the cost-effectiveness of proposed PoMs. PMID:19213994

  18. Critical source times for nutrient loss in agricultural catchment streams

    NASA Astrophysics Data System (ADS)

    Melland, Alice; Shore, Mairead; Mellander, Per-Erik; McDonald, Noeleen; Shortle, Ger; Murphy, Paul; Jordan, Phil

    2014-05-01

    Identifying periods of the year when there is a high risk of incidental nutrient loss from farms via runoff to streams underpins current nutrient management legislation in Europe. This research explored high-temporal resolution nutrient transfer patterns relative to the time that manure and fertiliser are prohibited from being spread (the mandatory spreading 'closed' period) in five Irish agricultural catchments. Catchment nutrient losses during the 12 week closed periods in 2009-10, 2010-11 and 2011-12 were compared with losses during the remainder of the year, and with losses in the two week 'shoulder' periods immediately before and after the closed period. The closed period losses were assumed to be residual from soil nutrient stores and the 'shoulder' periods were considered to also include incidental losses. Nutrient loss was measured at sub-hourly frequency as total phosphorus (P) and total oxidised nitrogen (mostly nitrate-N) fluxes in streamflow. The streamflow fluxes showed that the proportion of the annual nitrate-N loss occurring during the closed periods (33-61%) was high compared with the remainder of the year. Six to ten times more nitrate-N loss occurred in the two weeks after, compared with the two weeks before, the closed period. These two week 'shoulder' period losses were, on average, less than or equal to 2.5 kg nitrate-N/ha and 9% of total annual nitrate-N loss in streamflow. On average, 40-53% of the annual P loss occurred during the closed periods but in a runoff-prone catchment in a year with a wet summer, the closed period was the less risky period. Similar to nitrate-N, two to twenty times more P loss occurred in the two weeks after, compared with the two weeks before, the closed period. These shoulder period losses were, on average, less than or equal to 0.027 kg/ha and 4.2% of total annual P loss in streamflow. The proportion of the shoulder period loss that could be attributed to recently spread nutrients was not known but can be

  19. Quantifying subsurface mixing of water and nutrients in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Van der Velde, Y.; Torfs, P.; Van Der Zee, S.; Uijlenhoet, R.

    2011-12-01

    The distribution of time it takes water from the moment of rainfall to reach the catchment outlet is widely used to characterize catchment-scale groundwater-surface water interactions, catchment vulnerability to pollution spreading and pollutant loads from catchments to downstream waters. However, this distribution tends to vary in time driven by rainfall and evapotranspiration, which compromises the applicability of a single travel time distribution as catchment characteristic. Recent studies suggested that subsurface mixing controls to what extent dynamics in rainfall and evpotranspiration are translated into dynamics of travel time distributions of individual water flows. This new insight in hydrologic functioning of catchments requires new definitions and concepts that link dynamics of catchment travel time distributions to the degree of subsurface mixing. We propose the concept of Refresh Rate Functions (RRF) and will demonstrate how RRFs directly quantify subsurface mixing within a catchment, allow for deriving transient as well as temporally averaged travel time distributions of a catchment and are largely independent of weather or climate. The presented analyses will use a unique dataset of high-frequent nitrate concentrations in an agricultural catchment in the Netherlands to reveal the effects of mixing dynamics inside a catchment on stream water nitrate concentrations. These measurements will be compared with calculations by a spatially distributed groundwater model and conceptual models of water flow and solute transport. Remarkable findings are the large contrasts in discharge behavior expressed in travel time between lowland and sloping catchments and the strong relation between evapotranspiration and stream water nitrate concentration dynamics.

  20. Proximate and ultimate controls on carbon and nutrient dynamics of small agricultural catchments

    NASA Astrophysics Data System (ADS)

    Thomas, Z.; Abbott, B. W.; Troccaz, O.; Baudry, J.; Pinay, G.

    2015-09-01

    Direct and indirect effects from agriculture, urbanization, and resource extraction have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. The capacity of a watershed to remove or retain nutrients is a function of biotic and abiotic conditions across the terrestrial-aquatic gradient including soil, groundwater, riparian zone, and surface water. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments. We analysed a five-year, high frequency water chemistry dataset from 3 catchments ranging from 2.3 to 10.8 km2 in northwestern France. Catchments differed in the relationship between hydrology and solute concentrations, associated with catchment characteristics such as hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness appeared to have greater transient storage and residence time, buffering the catchment to fluctuations in water chemistry, reflected in relatively invariant carbon and nutrient chemistry across hydrologic conditions. Conversely, the catchments with smoother, thinner soils responded to both intra- and inter-annual hydrologic variation with high concentrations of PO43- and NH4+ during low flow conditions and strong increases in DOC, sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land use) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on elemental fluxes is both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent catchment buffering capacity and probability of human

  1. Proximate and ultimate controls on carbon and nutrient dynamics of small agricultural catchments

    NASA Astrophysics Data System (ADS)

    Thomas, Zahra; Abbott, Benjamin W.; Troccaz, Olivier; Baudry, Jacques; Pinay, Gilles

    2016-03-01

    Direct and indirect effects from human activity have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. Despite an abundance of studies investigating the impact of agricultural activity on water quality, our understanding of what determines the capacity of a watershed to remove or retain nutrients remains limited. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments by investigating the relationship between catchment characteristics, stream discharge, and water chemistry. We analyzed a 5-year, high-frequency water chemistry data set from three catchments in western France ranging from 2.3 to 10.8 km2. The relationship between hydrology and solute concentrations differed between the three catchments and was associated with hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness had relatively invariant carbon and nutrient chemistry across hydrologic conditions, indicating high resilience to human disturbance. Conversely, the catchments with smoother, thinner soils responded to both intra- and interannual hydrologic variation with high concentrations of phosphate (PO43-) and ammonium (NH4+) in streams during low flow conditions and strong increases in dissolved organic carbon (DOC), sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land-use configuration) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on water quality was both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent

  2. A review of monitoring approaches and outcomes of surface water quality mitigation measures in meso-scale agricultural catchments

    NASA Astrophysics Data System (ADS)

    Melland, Alice; Jordan, Phil; Murphy, Paul; Mellander, Per-Erik; Shortle, Ger

    2013-04-01

    Critical for an informative feedback loop from scientific monitoring of biophysical change, to making and implementing suitable policy to effect the desired change, are both accurate measurement of biophysical change, and measurement or modelling of the causes of change. For example the European Environment Agency uses the DPSIR framework to assess change in the state (S) of natural resources due to changes in specific drivers (D) and pressures (P) that can have an impact (I) and are the focus of policy responses (R). This paper provides a review of meso-catchment scale studies worldwide that have measured the impacts of agricultural land management practice on surface water quality. Approaches for measuring water quality impacts of agricultural mitigation practices in meso-catchments (1-100 km2) ranged from measuring water quality over a time series, such as before and after a land management change, or over a spatial series such as in paired catchments with and without agricultural practice change (or over a gradient of practices or catchment types), and by cause and effect studies that measure sources, pathways and impacts of practices. Agricultural mitigation measures had no measurable effect, or positive, or negative effects on water quality over periods of 3 to 20 years. In most catchments where beneficial effects of mitigation measures were successfully measured, combinations of measures that address nutrient or pollutant sources, pathways, delivery and impact have been implemented. Successful farm measures included substantial reductions in the intensity of the farming systems, improved engineering and crop management to reduce runoff and drainage transport of nutrients and sediment, as well as high rates of implementation of measures across the catchments. In many cases, the potential to measure improvement in one or more water quality indicators was limited by the impact of a few management or weather events. Reasons that water quality did not improve in

  3. Recent trends in water quality in an agricultural catchment in Eastern Scotland: elucidating the roles of hydrology and land use.

    PubMed

    Dunn, S M; Sample, J; Potts, J; Abel, C; Cook, Y; Taylor, C; Vinten, A J A

    2014-07-01

    Across the EU, programmes of measures have been introduced as part of river basin management planning as a means of tackling problems of diffuse pollution from agriculture. Evidence is required to demonstrate the effectiveness of these measures and with this overarching objective, monitoring of an agricultural catchment in Eastern Scotland was initiated in 2007. As a precursor to evaluating the effect of new management measures it is essential to understand how other factors, including hydrology and land use changes, could have influenced water quality. This study undertook an analysis of the trends in concentrations and loads of nitrate, soluble reactive phosphorus (SRP), suspended solids (SS) and turbidity measured at six points in the catchment over a six year period. The results identified both differing trends between determinands and differing trends occurring over varying spatial scales. The only direct relationships between land use and water quality that could be identified based on annual data was a positive link between arable cropping and nitrate concentrations. At the sub-catchment scale some temporal changes in land use and management explained short-term trends in nitrate but not in SRP. Lags in the system were identified due to soil adsorption, in-stream/loch processing and groundwater transport making the identification of cause and effect problematic. The results have implications for the demonstration of effectiveness of measures over the shorter term and the timescales of recovery from diffuse pollution. Longer term monitoring at small scales will be important in this regard. PMID:24718675

  4. Monitoring Two Small Catchments to Evaluate Effects of No-Tillage Agricultural Management in São Paulo State, Brazil

    NASA Astrophysics Data System (ADS)

    Figueiredo, R. D. O.; Gonçalves, A. O.; Melo, A. D. S.; de Bona, F. D.; Hernani, L. C.

    2015-12-01

    In recent years, declines in water and soil quality have been observed in areas of Brazil where no-till agriculture had been previously implemented. Poor soil management associated with the absence of public policies has caused soil erosion, because many farmers are moving back from no-till to traditional cultivation for faster economic gains. A research project - SoloVivo Project - leaded by Embrapa (Brazilian Agricultural Research Corporation) in partnership with Itaipu Binacional aims to develop and validate, in a participatory way, tools to evaluate the technical performance of soil and water management at the rural properties that practice no-till agriculture. In this context we have selected two paired small (< 100 ha) catchments in the Paranapanema region, São Paulo State, where no-till management is practiced at two different degrees of effectiveness. In the figure bellow it can be seen a scene of one of the two studied catchments. For monitoring rainfall, soil solution and stream water, each catchment will be equipped with a programmable datalogger (with cell phone communication for data collection) linked to: a high intensity tipping bucket rain gage; a reflectometer to monitor soil volumetric water content, bulk electric conductivity and temperature; a radar water level sensor; a turbidity sensor; and an electric conductivity-temperature probe. We expect that stream flow and sediment generation, besides water quality (measured by conductivity) may serve as indicators of the benefits of no-tillage agriculture done more or less well. The results of this study will be used to stimulate discussions at workshops with the farmers who participate in a rural producers association in the region. In addition this and other results can be used to help the Brazilian National Water Agency (ANA) decide about applying no-till agricultural management systems in its programs of payment for environmental services.

  5. Establishing a sediment budget for a small agricultural catchment in southern Brazil, to support the development of effective sediment management strategies

    NASA Astrophysics Data System (ADS)

    Minella, Jean P. G.; Walling, Desmond E.; Merten, Gustavo H.

    2014-11-01

    The rapid expansion of agriculture in Brazil has increased erosion rates and sediment yields, causing many negative environmental and economic impacts, both on- and off-site. However, to date, very few catchment-scale sediment budget investigations have been carried out in Brazil. Given the need to reduce the negative off-site impacts of increasing agricultural activity, there is an important need for such investigations in order to inform the development of effective sediment management strategies. Against this background, 137Cs measurements have been combined with measurements of sediment yield and fingerprinting the source of the fine sediment output, to establish a provisional sediment budget for a small (1.19 km2) agricultural catchment in southern Brazil. The catchment is located in an area of steep highly erodible basaltic terrain, which has been intensively cultivated with tobacco. An ongoing monitoring programme provided information on the sediment yield from the catchment and existing suspended sediment source fingerprinting investigations provided information on the main sediment sources contributing to the sediment load at the catchment outlet. 137Cs measurements have been used to estimate medium-term erosion and deposition rates along 17 transects across the cultivated slopes and to quantify sedimentation rates within valley floor sediment sinks. These data have been used to estimate sediment redistribution rates within the cultivated areas of the study catchment and sediment accumulation in the valley floor sinks. The information provided by the three primary data sources has been integrated to establish the sediment budget for the catchment over the past 57 years. The individual terms of the budget necessarily involve much uncertainty, but its closure adds confidence to the final result. The budget calculations indicate that the study catchment has a sediment delivery ratio of ∼15%. The implications of the key features of the budget for developing

  6. Replacing Concrete with Natural and Social Engineering: Learning the Lessons of Stakeholder Engagement from South West Water's Upland Catchment Management Programme

    NASA Astrophysics Data System (ADS)

    Smith, David; Grand-Clement, Emile; Brazier, Richard

    2014-05-01

    Replacing Concrete with Natural and Social Engineering: Learning the Lessons of Stakeholder Engagement from South West Water's Upland Catchment Management Programme Smith, D., Grand-Clement, E., Anderson, K., Luscombe, D., G, N., Bratis, Brazier, R.E Peatlands in the South West of the British Isles have been extensively drained for agricultural reclamation and peat cutting. The improvement in food production resulting from this management practice has never clearly been observed. Instead, we are now faced with several detrimental consequences on a whole suite of ecosystem services, such as the delivery of water, water quality, biodiversity and carbon storage. Alongside the direct environmental implications, poor water quality is increasing water treatment costs and will drive significant future investment. As a result, water companies now need to find appropriate solutions to varying water levels and decreasing water quality through catchment management. The Mires Project, the catchment management programme used by South West Water (SWW) is working with a wide range of stakeholders to restore the hydrological functioning of peatlands, and the ecosystem services they provide. This programme is driven by overarching legal requirements (i.e. the water framework directive, Natura 2000), future climate change predictions, corporate responsibility and commercial needs. Post-restoration scientific monitoring is at the heart of the project improving of our understanding of the eco-hydrological and chemical process driving changes in management practice. The challenges faced from the involvement of a wide range of stakeholders will be explored, focusing on the benefits from stakeholder involvement in catchment management and hydrological research, but also considering the difficulties to be overcome. SWW is working with private land-owners, government agencies, local and national park Authorities, community and single interest groups and research institutions to achieve its

  7. [Contribution of Base Flow to Total Nitrogen Loading in Subtropical Agricultural Catchments].

    PubMed

    Ma, Qiu-mei; Li, Wei; Wang, Yi; Liu, Xin-liang; Li, Yong; Wu, Jin-shui

    2016-04-15

    With the fast development of economics and improvement of people's living standard, non-point source pollution of the agricultural catchments in subtropical China has become more and more severe, where water quality deterioration has become a main barrier for sustainable development and ecological restoration. The process of ecohydrology in catchment is greatly influenced by the process of base flow in channel. This study selected the Tuojia and Jianshan catchments located in Changsha County, Hunan Province, to quantify and compare the contribution of base flow to total nitrogen (TN) loading from January 2011 to December 2013, through field observation and model estimation. The results suggested that the Tuojia catchment with higher intensity of rice agriculture had the greater volume of base flow, higher average flow-weighted TN concentration in base flow, and greater monthly TN loading via base flow [15.2 mm · month⁻¹, 4.14 mg · L⁻¹ and 0.54 kg · (hm² · month)⁻¹, respectively] than those in the Jianshan catchment with lower intensity [11.4 mm · month⁻¹, 1.72 mg · L⁻¹ and 0.20 kg · (hm² · month)⁻¹, respectively]. The base flow contribution to TN loading showed an apparently seasonal pattern. During rice-growing seasons, the contributions of base flow to TN loading were 23.2% and 18.6% in the Tuojia and Jianshan catchments, respectively, lower than those in the fallow seasons (46.9% and 40.0% correspondingly. These results suggested that rice agriculture increased the contribution of base flow in the fallow season to TN loading. Therefore, to alleviate the suffering of non-point source pollution in the rice agriculture catchments, reasonable management measure of rice fields should be implemented to decrease contrihution of base flow to TN loading. PMID:27548958

  8. Interacting effects of climate and agriculture on fluvial DOM in temperate and subtropical catchments

    NASA Astrophysics Data System (ADS)

    Graeber, D.; Goyenola, G.; Meerhoff, M.; Zwirnmann, E.; Ovesen, N. B.; Glendell, M.; Gelbrecht, J.; Teixeira de Mello, F.; Gonzalez-Bergonzoni, I.; Jeppesen, E.; Kronvang, B.

    2015-05-01

    Dissolved organic matter (DOM) is an important factor in aquatic ecosystems, which is involved in a large variety of biogeochemical and ecological processes, and recent literature suggests that it could be strongly affected by agriculture in different climates. Based on novel monitoring techniques, we investigated the interaction of climate and agriculture effects on DOM quantity and quality. To examine this, we took water samples over 2 years in two paired intensive and extensive farming catchments in each of Denmark (temperate climate) and Uruguay (subtropical climate). We measured dissolved organic carbon (DOC) and nitrogen (DON) concentrations and DOC and DON molecular fractions with size-exclusion chromatography. Moreover, we characterized DOM quality with absorbance and fluorescence measurements, as well as parallel factor analysis (PARAFAC). We also calculated the DOC and DON loads based on daily discharge measurements, as well as measured precipitation and air temperature. The fluvial DOM in the catchments in Uruguay was characterized by higher temporal variability of DOC and DON loads which were clearly to a higher temporal variability of precipitation and a DOM composition with rather plant-like character relative to the Danish catchments. Moreover, we found a consistently higher temporal variability of DOC and DON loads in the intensive farming catchments than in the extensive farming catchments, with highest temporal variability in the Uruguayan intensive farming catchment. Furthermore, the composition of DOM exported from the intensive farming catchments was consistently complex and always related to microbial processing in both Denmark and Uruguay. This was indicated by low C : N ratios, several spectroscopic DOM composition indices and PARAFAC fluorescence components. We propose that the consistent effect of intensive farming on DOM composition and the temporal variability of DOC and DON loads is related to similarities in the management of

  9. Quantifying faecal indicator organism hydrological transfer pathways and phases in agricultural catchments.

    PubMed

    Murphy, S; Jordan, P; Mellander, P-E; O' Flaherty, V

    2015-07-01

    Faecal indicator organisms (FIOs) can impact on water quality and pose a health and environmental risk. The transfer of FIOs, such as Escherichia coli (E. coli), from land to water is driven by hydrological connectivity and may follow the same flowpaths as nutrients, from agricultural and human sources. This study investigated E. coli transfer in two catchment areas with high source and transport pressures. These pressures were: organic phosphorus (P) loading; human settlement; conduits and fissures in a grassland karst area; and clay rich and impermeable soils in a mixed arable area. The occurrence of E. coli and its transport pathways, along with the pathways of nutrients, were studied using a combination of targeted FIO sampling, during different hydrological phases and events, and high resolution nutrient analysis. The quick flow component in both catchments was found to be a more potent vector for E. coli, and was coincident with the total P flowpaths using a P Loadograph Recession Analysis (LRA). The karst grassland catchment was found to be a transport limited system and the mixed arable catchment a source limited system. Hence, despite the grassland catchment being a potentially higher FIO source, the E. coli loads leaving the catchment were low compared to the mixed arable catchment. E. coli load whole-event comparisons also indicated that the grassland karst transfers tended to be much lower on falling phases of runoff, while the arable catchment, over greywacke and mudstone geology, showed little change between the phases. Furthermore, the arable catchment showed asymptotic decline of sustained E. coli loads towards low flows, which may be indicative of chronic point sources. These results indicate the dominance of transport mechanisms over source mechanisms for mass E. coli loads and also chronic loads during low flow. These will be important considerations for risk assessment and mitigation. PMID:25840482

  10. Hydrologic control of dissolved organic matter concentration and quality in a semiarid artificially drained agricultural catchment

    NASA Astrophysics Data System (ADS)

    Bellmore, Rebecca A.; Harrison, John A.; Needoba, Joseph A.; Brooks, Erin S.; Kent Keller, C.

    2015-10-01

    Agricultural practices have altered watershed-scale dissolved organic matter (DOM) dynamics, including in-stream concentration, biodegradability, and total catchment export. However, mechanisms responsible for these changes are not clear, and field-scale processes are rarely directly linked to the magnitude and quality of DOM that is transported to surface water. In a small (12 ha) agricultural catchment in eastern Washington State, we tested the hypothesis that hydrologic connectivity in a catchment is the dominant control over the concentration and quality of DOM exported to surface water via artificial subsurface drainage. Concentrations of dissolved organic carbon (DOC) and humic-like components of DOM decreased while the Fluorescence Index and Freshness Index increased with depth through the soil profile. In drain discharge, these characteristics were significantly correlated with drain flow across seasons and years, with drain DOM resembling deep sources during low-flow and shallow sources during high flow, suggesting that DOM from shallow sources bypasses removal processes when hydrologic connectivity in the catchment is greatest. Assuming changes in streamflow projected for the Palouse River (which contains the study catchment) under the A1B climate scenario (rapid growth, dependence on fossil fuel, and renewable energy sources) apply to the study catchment, we project greater interannual variability in annual DOC export in the future, with significant increases in the driest years. This study highlights the variability in DOM inputs from agricultural soil to surface water on daily to interannual time scales, pointing to the need for a more nuanced understanding of agricultural impacts on DOM dynamics in surface water.

  11. Using long time series of agricultural-derived nitrates for estimating catchment transit times

    NASA Astrophysics Data System (ADS)

    Fovet, O.; Ruiz, L.; Faucheux, M.; Molénat, J.; Sekhar, M.; Vertès, F.; Aquilina, L.; Gascuel-Odoux, C.; Durand, P.

    2015-03-01

    The estimation of water and solute transit times in catchments is crucial for predicting the response of hydrosystems to external forcings (climatic or anthropogenic). The hydrogeochemical signatures of tracers (either natural or anthropogenic) in streams have been widely used to estimate transit times in catchments as they integrate the various processes at stake. However, most of these tracers are well suited for catchments with mean transit times lower than about 4-5 years. Since the second half of the 20th century, the intensification of agriculture led to a general increase of the nitrogen load in rivers. As nitrate is mainly transported by groundwater in agricultural catchments, this signal can be used to estimate transit times greater than several years, even if nitrate is not a conservative tracer. Conceptual hydrological models can be used to estimate catchment transit times provided their consistency is demonstrated, based on their ability to simulate the stream chemical signatures at various time scales and catchment internal processes such as N storage in groundwater. The objective of this study was to assess if a conceptual lumped model was able to simulate the observed patterns of nitrogen concentration, at various time scales, from seasonal to pluriannual and thus if it was relevant to estimate the nitrogen transit times in headwater catchments. A conceptual lumped model, representing shallow groundwater flow as two parallel linear stores with double porosity, and riparian processes by a constant nitrogen removal function, was applied on two paired agricultural catchments which belong to the Research Observatory ORE AgrHys. The Global Likelihood Uncertainty Estimation (GLUE) approach was used to estimate parameter values and uncertainties. The model performance was assessed on (i) its ability to simulate the contrasted patterns of stream flow and stream nitrate concentrations at seasonal and inter-annual time scales, (ii) its ability to simulate the

  12. The impact of land management in agricultural catchments on groundwater pollution levels

    NASA Astrophysics Data System (ADS)

    Matysik, Magdalena

    2014-10-01

    Agricultural activity results in water pollution from nitrogen and phosphorus compounds. Increased concentrations of nitrogen compounds pose a threat to animal and human health. The purpose of this study was to determine the impact of agriculture in a catchment basin on the level of groundwater pollution from biogenic compounds. Spatial analysis of the land cover was conducted using a GIS and was based on data from the Corine Land Cover databases.

  13. Sediment fingerprinting in agricultural catchments: A critical re-examination of source discrimination and data corrections

    NASA Astrophysics Data System (ADS)

    Smith, Hugh G.; Blake, William H.

    2014-01-01

    Fine sediment source fingerprinting techniques have been widely applied in agricultural river catchments. Successful source discrimination in agricultural environments depends on the key assumption that land-use source signatures imprinted on catchment soils are decipherable from those due to other landscape factors affecting soil and sediment properties. In this study, we re-examine this critical assumption by investigating (i) the physical and chemical basis for source discrimination and (ii) potential factors that may confound source un-mixing in agricultural catchments, including particle size and organic matter effects on tracer properties. The study is situated in the River Tamar, a predominantly agricultural catchment (920 km2) in south-west England that has also been affected by mining. Source discrimination focused on pasture and cultivated land uses and channel banks. Monthly, time-integrated suspended sediment samples were collected across seven catchments for a 12-month period. Physical and chemical properties measured in source soils and sediment included fallout radionuclides (137Cs, excess 210Pb), major and minor element geochemical constituents, total organic carbon and particle size. Source discrimination was entirely dependent on differences in tracer property concentrations between surface and sub-surface soils. This is based on fallout radionuclide concentrations that are surface-elevated, while many geochemical properties are surface-depleted due to weathering and pedogenetic effects, although surface soil contamination can reverse this trend. However, source discrimination in the study catchments was limited by (i) rotation of cultivated and pasture fields resulting in reduced differences between these two sources, and (ii) the cultivated source signature resembling a mix of the pasture and channel bank sources for many tracer properties. Furthermore, a combination of metal pollution from abandoned historic mines and organic enrichment of

  14. Estimation of groundwater contribution in runoff from small agricultural dominated catchments

    NASA Astrophysics Data System (ADS)

    Deelstra, Johannes; Jansons, Viesturs; Lagzdiņš, Ainis

    2013-04-01

    Under poor natural drainage condition, agricultural land has to be provided with subsurface drainage systems to discharge excess water from the rootzone, thereby guaranteeing optimal cropping conditions during the growing season, while in addition facilitating land preparation. Subsurface drainage systems can significantly contribute in runoff and nutrient loss generation. A secondary effect of drainage systems is that it reduces surface runoff and thereby erosion and phosphorus loss. In addition to surface and subsurface runoff, a third component, being groundwater, is contributing in runoff. As only information about the total runoff at the catchment outlet is available, uncertainty exists about the contribution of the different flow processes. Agriculture is a main contributor of nutrients and sediments to surface water causing water quality problems. Knowledge about the different pathways of water and hence nutrients and sediments to open water systems is important with respect to the choice of mitigation measures in agricultural dominated catchments. Estimates of groundwater or baseflow contribution (BFI) are often based on the use of digital filters applied to average daily discharge values. When using recommended values for the digital filter, this resulted in BFI of 40 - 50 % when applied to small Norwegian agricultural catchments. When taking the poor natural drainage conditions into consideration in addition to the presence of heavy marine clay deposits at depths greater than 1 - 2 m below soil surface, these values are considered unrealistically high. Deelstra et al (2010) showed that small agricultural catchments can have rather "flashy" runoff behaviour, characterised by large diurnal variations in discharge which also contradicts high baseflow contributions. An approach to obtain a realistic filter parameter for a digital filter has been carried out, based on discharge measurements on a set of small, nested catchments in Norway and further tested in

  15. Linking Groundwater Nitrate-N Concentrations to Management and Hydrological Changes in two Agricultural Catchments

    NASA Astrophysics Data System (ADS)

    Mellander, Per-Erik; Melland, Alice R.; Jordan, Philip; Murphy, Paul N. C.; Shortle, Ger

    2013-04-01

    In order to minimize Nitrogen (N) transfer from groundwater to surface water in agricultural river catchments it is useful to understand how those transfer pathways may vary over time and space, and thus in their connection to nutrient sources and potential effects of temporal changes in water recharge and land management. In this paper we investigate the links between N sources, groundwater and surface water, as well as the implication of spatiotemporal variability for mitigation measures. We present three years of N concentrations in stream water (sub-hourly) and in groundwater (monthly) of different strata in four hillslopes in two ca 10 km2 Irish agricultural catchments with permeable soils. One catchment with arable land overlying slate bedrock and the other with intensively managed grassland on sandstone. Both catchments were dominated by delayed nutrient transfer pathways via groundwater. Relatively high concentrations of N were found in the groundwater of both catchments, attributed to leaching of surplus soil nitrate-N. The Grassland/sandstone catchment had locally higher nitrate-N concentrations in the groundwater with more spatiotemporal variability than in the groundwater of the Arable/Slate catchment. The N concentrations in the stream water of the Arable/Slate catchment were more directly reflected by groundwater conditions. In one hillslope the effects of pasture reseeding were observed by locally elevated N concentrations in the groundwater with a delay of ca five months. This was not reflected in the surface water despite groundwater dominating the contribution to stream water. In another hillslope N was naturally buffered in the near-stream zone, but this zone was bypassed with high nitrate-N content water from the uplands via tile-drains. The apparent spatiotemporal variability in N concentration highlights the need for insight into these differences when interpreting groundwater quality data from a limited number of sampling points and occasions

  16. Assessment of suspended matter transport in a large agricultural catchment using the MOHID water modelling system

    NASA Astrophysics Data System (ADS)

    David, Bailly; David, Brito; Chantha, Oeurng; Ramiro, Neves; Sabine, Sauvage; Sánchez-Pérez, José-Miguel

    2010-05-01

    Suspended sediment transport from agricultural catchments to stream networks is responsible for impaired water quality, reservoir sedimentation and the transport of sediment-bound pollutants (pesticides, particulate nutrients, metals and other adsorbed toxic substances). The dynamic of pollutants adsorbed on sediment and associated with particulate organic carbon, from land areas into stream network arises mainly from erosion and sedimentation processes. It is known that up to 90% of suspended sediment is transported during flood event and therefore quick flood events have a major impact on pollutant transport. This study - part of the EU AguaFlash (http://www.aguaflash-sudoe.eu/) project - examined and quantified suspended sediment dynamics from catchment to river (erosion, transport, deposition on hillside and in the river). Semi-distributed, physics-based watershed or reservoir models are generally used to simulate sediment dynamics. One of the limitations of this kind of modelling is that transport along agricultural field and the possibility of deposition of suspended sediments in hillslopes are not considered. Consequently, all sediments eroded are assumed to be accumulated in the river and the sediment and associated pollutant dynamics are over- or under-estimated. In our approach, the mechanistic physics-based water modelling system MOHID (http://www.mohid.com) was used to quantify soil erosion and sediment transport processes at the local and macroscopic scale. This paper present the erosion and transport mathematical model and modelling strategy used and compares our initial results with filed data obtained on an 1100 km² intensive agricultural catchment (Save catchment, South-west France) during 2007-2009 and with simulation data produced using SWAT (Soil and Water Assessment Tool, 2005 version). The contribution of the MOHID model compared with that of the semi-distributed SWAT model is discussed. Keywords: Erosion, suspended sediment, transport

  17. Plot and Catchment Scale Hydrological Impacts of Agricultural Field Boundary Features

    NASA Astrophysics Data System (ADS)

    Coates, Victoria; Pattison, Ian

    2015-04-01

    Natural flood management aims to reduce downstream flow levels by delaying the movement of water through a catchment and increasing the amount of soil infiltration. Field boundary features such as hedgerows and dry stone walls are common features in the rural landscape. It is hypothesised that there presence could reduce runoff connectivity and change the soil moisture levels by altering the soil structure and porosity. The use of larger agricultural machinery has resulted in the removal of field boundaries and the subsequent increase in field sizes over the 20th Century. This change in the rural landscape is likely to have changed the partitioning of rainfall into runoff and the hydrological pathways throughout the catchment. However, the link between field boundaries and catchment scale flood risk has not yet been proven. We aim to address this need for evidence to support natural flood management by focussing on these widespread features in the rural landscape. Firstly, we quantify the change in the density of field boundaries over the past 120 years for the Skell catchment, Northern England using historical OS maps. The analysis has shown that field size has approximately doubled in the Skell catchment since 1892, due to the removal of field boundaries. Secondly, we assess the effect of field boundaries on local soil characteristics and hydrological processes through plot scale continuous monitoring of the hydrological processes along a 20m transect through the linear boundary features. For the summer period results show that soil moisture levels are lower immediately next to the hedgerow compared to distances greater than 1m from the hedgerow. Finally, we use this data to parameterise and validate a catchment scale hydrological model. The model is then applied to test the impact of a network of field boundaries on river flow extremes at the catchment scale.

  18. Impact of agricultural practices and river catchment characteristics on river and bathing water quality.

    PubMed

    Aitken, M N

    2003-01-01

    The objective was to investigate the potential risk of faecal indicator organism (FIO) bacteriological contamination of river catchments and coastal bathing waters from farm management practices and to develop practices to reduce the risk. A risk assessment on 117 farms was carried out in two river catchments in south-west Scotland. Manure storage facilities, farming practices, field conditions and catchment characteristics were assessed. River samples at 33 locations were regularly taken and analysed for FIOs. Available manure storage capacity and farm management practices are inadequate on a high proportion of farms and FIO contamination of watercourses was likely the result of effluent transported into watercourses due to non-collection or poor containment. In addition, surface run-off or leaching following land application of manure or intensive stocking in adverse conditions was a high risk on up to 50% of farms. The concentrations of FIOs in the streams of two sub-catchments with high livestock intensity was 4 to 8 times higher compared to the two sub-catchments which had a low livestock intensity. The majority of potential risks of agricultural pollution to watercourses may be eliminated through improved manure and dirty water management, forward planning of manure spreading activities and improved operational procedures. PMID:15137173

  19. Agricultural management change effects on river nutrient yields in a catchment of Central Greece

    NASA Astrophysics Data System (ADS)

    Panagopoulos, Y.

    2009-04-01

    Modelling efforts are strongly recommended nowadays by European legislation for investigating non-structural mitigation measures against water pollution on catchment scale. Agricultural diffuse pollution is considered to be the main responsible human activity for the Eutrophication of inland waters with nitrogen (N) and phosphorus (P). The physically-based water quality model SWAT is implemented in an agricultural medium-size agricultural catchment of Central Greece with the purpose to simulate the baseline situation and subsequently to predict the effects that realistic non-structural interventions, applied on the agricultural land, have on water quality and crop yields. SWAT was successfully calibrated according to measured flows and water quality data and subsequently scenarios were developed by changing chemical fertilizer application rates and timing on corn, cotton and wheat cultivations. All scenarios resulted in a decrease of nutrient emissions to surface waters but with a simultaneous small decrease in crop yields. The model predicted explicitly the consequences of non-structural mitigation measures against water pollution sustaining that the understanding of land management changes in relation to its driving factors provides essential information for sustainable management of the agricultural sector in an agricultural country like Greece.

  20. Urbanization and agriculture increase exports and differentially alter elemental stoichiometry of dissolved organic matter (DOM) from tropical catchments.

    PubMed

    Gücker, Björn; Silva, Ricky C S; Graeber, Daniel; Monteiro, José A F; Boëchat, Iola G

    2016-04-15

    Many tropical biomes are threatened by rapid land-use change, but its catchment-wide biogeochemical effects are poorly understood. The few previous studies on DOM in tropical catchments suggest that deforestation and subsequent land use increase stream water dissolved organic carbon (DOC) concentrations, but consistent effects on DOM elemental stoichiometry have not yet been reported. Here, we studied stream water DOC concentrations, catchment DOC exports, and DOM elemental stoichiometry in 20 tropical catchments at the Cerrado-Atlantic rainforest transition, dominated by natural vegetation, pasture, intensive agriculture, and urban land cover. Streams draining pasture could be distinguished from those draining natural catchments by their lower DOC concentrations, with lower DOM C:N and C:P ratios. Catchments with intensive agriculture had higher DOC exports and lower DOM C:P ratios than natural catchments. Finally, with the highest DOC concentrations and exports, as well as the highest DOM C:P and N:P ratios, but the lowest C:N ratios among all land-use types, urbanized catchments had the strongest effects on catchment DOM. Thus, urbanization may have alleviated N limitation of heterotrophic DOM decomposition, but increased P limitation. Land use-especially urbanization-also affected the seasonality of catchment biogeochemistry. While natural catchments exhibited high DOC exports and concentrations, with high DOM C:P ratios in the rainy season only, urbanized catchments had high values in these variables throughout the year. Our results suggest that urbanization and pastoral land use exerted the strongest impacts on DOM biogeochemistry in the investigated tropical catchments and should thus be important targets for management and mitigation efforts. PMID:26849342

  1. Groundwater denitrification in two agricultural river catchments: influence of hydro-geological setting and aquifer geochemistry

    NASA Astrophysics Data System (ADS)

    McAleer, Eoin; Mellander, Per-Erik; Coxon, Catherine; Richards, Karl G.; Jahangir, Mohammad M. R.

    2015-04-01

    Identifying subsurface environments with a natural capacity for denitrification is important for improving agricultural management. At the catchment scale, a complex hierarchy of landscape, hydro-geological and physico-chemical characteristics combine to affect the distribution of groundwater nitrate (NO3-). This study was conducted along four instrumented hillslopes in two ca. 10km2 agricultural river catchments in Ireland, one dominated by arable and one by grassland agriculture. Both catchments are characterised by well drained soils, but have differing aquifer characteristics. The arable catchment is underlain by weathered Ordovician slate bedrock which is extensively fractured with depth. The grassland catchment is characterised by Devonian sandstone bedrock, exhibiting both lateral (from upslope to near stream) and vertical variations in permeability along each hillslope. The capacity for groundwater denitrification was assessed by examining the concentration and distribution patterns of N species (total nitrogen, nitrate, nitrite, ammonium), dissolved organic carbon (DOC), dissolved oxygen (DO) and redox potential (Eh) in monthly samples from shallow and deep groundwater piezometers (n=37). Additionally, the gaseous products of denitrification: nitrous oxide (N2O) and excess dinitrogen (excess N2) were measured seasonally using gas chromatography and membrane inlet mass spectroscopy, respectively. The slate catchment was characterised by uniformity, both laterally and vertically, in aquifer geochemistry and gaseous denitrification products. The four year spatial mean groundwater NO3--N concentration was 6.89 mg/l and exhibited low spatial and temporal variability (temporal SD: 1.19 mg/l, spatial SD: 1.185 mg/l). Elevated DO concentrations (mean: 9.75 mg/l) and positive Eh (mean: +176.5mV) at all sample horizons indicated a setting with little denitrification potential. This non-reducing environment was reflected in a low accumulation of denitrification

  2. Overland flow and sediment transport in an agricultural lowland catchments: a focus on tile drain export

    NASA Astrophysics Data System (ADS)

    Vandromme, Rosalie; Grangeon, Thomas; Cerdan, Olivier; Manière, Louis; Salvador Blanes, Sébastien; Foucher, Anthony; Chapalain, Marion; Evrard, Olivier; Le Gall, Marion

    2016-04-01

    Rural landscapes have been extensively modified by human activities in Western Europe since the beginning of the 20th century in order to intensify agricultural production. Cultivated areas often expanded at the expense of grassland and wetlands located in lowland areas (de Groot et al., 2002). Therefore, large modifications were made to the agricultural landscapes: stream redesign, land consolidation, removal of hedges, and installation of tile drainage networks to drain the hydromorphic soils. These changes modified sediment processes and resulted in large morphological alterations (e.g. channel bed incision, deposition of fine sediment, channel bank erosion). Accordingly, these alterations threaten water quality and prevent to meet the requirements of the European directives. Improving water quality requires a clear understanding of the hydrosedimentary dynamics in these lowland cultivated catchments. However, few studies were conducted in drained environments. To fill this research gap, a pilot study was started in cultivated catchment of the Loire River basin, France, where tile drain densities are very high (> 1.5 km/km²). Six hydro-sedimentary monitoring stations were installed in the Louroux catchment (24 km²). One of them was specifically dedicated to measuring water/sediment fluxes from tile drains. Water level and turbidity were continuously monitored and sediments were sampled during floods and low stage periods. Samples were measured for particle size distribution, and sediment tracing studies are currently being developed to quantify the contribution of potential sources (e.g. surface vs subsurface, lithologies) to river sediment. Hydro-sedimentary fluxes were quantified and modelled for some selected events. The catchment hydrosedimentary fluxes and their properties were shown to be impacted by tile drain sediment transport, especially regarding particle size distribution, with the dominant export of very fine particles (< 2 μm) from tile drains

  3. Distribution of soil organic carbon in two small agricultural Mediterranean catchments.

    NASA Astrophysics Data System (ADS)

    Gomez, J. A.; Burguet, M.; Taguas, M. E.; Perez, R.; Ayuso, J. L.; Vanwallgehem, T.; Giraldez, J. V.; Vanderlinden, K.

    2012-04-01

    Soil organic carbon (SOC) is a key indicator of soil quality and a major factor for evaluating carbon sequestration schemes in forest and agricultural soils. However, at the farm or catchment scale SOC presents a large spatial variability which complicates the evaluation of soil quality (Gomez et al., 2009) and the certification of the potential for carbon sequestration. We hypothesize that the typical row crop configuration of olive orchards, with cover crops or bare soil in-between the rows, can explain a vast proportion of this variability. However, it is also expected that agricultural activities and topography-driven erosion processes at different scales (Van Oost et al., 2007) will contribute to SOC variability. Given the complexity of this problem and the important experimental effort required to resolve it, there are to our knowledge relatively few studies that have addressed this issue, especially in agricultural soils under Mediterranean conditions. This communications presents a preliminary evaluation of the top 1-m SOC content at two small, 8 and 6.7-ha, catchments in Southern Spain, covered by olive groves, that were intensively sampled in 2011. Spatial variability of SOC is analyzed across tree rows, areas in-between tree rows, and at different depths. The SOC distribution is evaluated against the topography of the catchment and the intensity of the water erosion processes analyzed by a simple model, such as SEDD, as used by Ferro and Porto (2000) and Taguas et al. (2011). The results of this communication will explore and discuss the differences between both catchments, and suggest guidelines for further exploring the sources of SOC variability, while providing guidelines to improve SOC estimation at the field scale for certification purposes.

  4. Apportioning sediment pressures on watercourses in grassland dominated agricultural catchments: a new framework for policy support

    NASA Astrophysics Data System (ADS)

    Collins, A.; Black, K.; Walling, D. E.; Wilson, P.

    2009-04-01

    Much of the effort directed towards monitoring and understanding soil erosion in the UK has focused upon arable farming systems, but the evidence base has suggested for some time that soil loss from grassland dominated landscapes can be enhanced by agricultural practises. Studies using composite source fingerprinting procedures have, for example, repeatedly highlighted the relative significance of managed pasture as a sediment source at catchment scale. Although traditional sediment sourcing approaches provide useful generic information for characterising sediment pressures, Catchment Officers working as part of the England Catchment Sensitive Farming Delivery Initiative (ECSFDI) also require higher resolution evidence to assist better the targeting of mitigation options. Accordingly, a new framework combining conventional sediment source fingerprinting and a dual signature tracking method has recently been tested in a grassland catchment in Cumbria, north-west England. The former provides information on the relative significance of generic sediment sources such as grassland or arable surface soils, damaged road verges and channel banks/subsurface sources, whereas the latter elucidates sediment loss from poached gateways or cattle tracks and wider areas of general hoofing damage in grass fields. Uncertainty and prior information are explicitly recognised by the novel framework.

  5. How agricultural landscape features control the transfer of nutrient and eutrophication risk in headwater catchments?

    NASA Astrophysics Data System (ADS)

    Dupas, Rémi; Delmas, Magalie; Dorioz, Jean-Marcel; Garnier, Josette; Moatar, Florentina; Gascuel-Odoux, Chantal

    2014-05-01

    The degradation of surface water quality due to nitrogen and phosphorus pollution is a major concern for drinking water quality and ecosystems health. Numerous studies have demonstrated that headwater catchments are large contributors of nutrient loads to downstream waters bodies. In terms of scientific understanding of the processes controlling nutrient transfers, headwater catchments are relevant spatial units to study the role of landscape features because of the relatively low contribution of point sources and in-stream processes compared to larger river networks. This paper presents an analysis of the variability in space and time of observed N and P loads for a dataset of 160 headwater catchments at a national level (France). A multivariate statistical analysis was performed to relate observed N and P loads to spatial attributes describing agricultural landscapes and the physical characteristics of the catchments: climate, topography, soils, etc. We identified factors controlling N and P loads and N:P:Si ratios in freshwaters; and specifically spatially described factors, by considering river corridors and interaction between soils and land use attributes. The same catchment dataset is used to calibrate the Nutting model, i.e. a statistical model developed to estimate nutrient emission to surface water, using readily available data in France (Dupas et al., 2013). Nutting is a statistical model linking N/P sources and catchment land and river attributes to estimate mean interannual nitrate-N, total-N, dissolved-P and total-P loads. It allows to extrapolate nutrient loads in unmonitored catchments at a national level and to estimate the risk of eutrophication in freshwaters considering Redfield's (1963) N:P:Si ratios. Results show that N is in excess over silica in 93% of French headwater bodies, and that phosphorus is in excess over silica in 26%-65% of French headwater catchments. This means that between 26% and 63% of French headwaters are at risk of

  6. Incidental nutrient transfers: Assessing critical times in agricultural catchments using high-resolution data.

    PubMed

    Shore, Mairead; Jordan, Phil; Melland, Alice R; Mellander, Per-Erik; McDonald, Noeleen; Shortle, Ger

    2016-05-15

    Managing incidental losses associated with liquid slurry applications during closed periods has significant cost and policy implications and the environmental data required to review such a measure are difficult to capture due to storm dependencies. Over four years (2010-2014) in five intensive agricultural catchments, this study used high-resolution total and total reactive phosphorus (TP and TRP), total oxidised nitrogen (TON) and suspended sediment (SS) concentrations with river discharge data to investigate the magnitude and timing of nutrient losses. A large dataset of storm events (defined as 90th percentile discharges), and associated flow-weighted mean (FWM) nutrient concentrations and TP/SS ratios, was used to indicate when losses were indicative of residual or incidental nutrient transfers. The beginning of the slurry closed period was reflective of incidental and residual transfers with high storm FWM P (TP and TRP) concentrations, with some catchments also showing elevated storm TP:SS ratios. This pattern diminished at the end of the closed period in all catchments. Total oxidised N behaved similarly to P during storms in the poorly drained catchments and revealed a long lag time in other catchments. Low storm FWM P concentrations and TP:SS ratios during the weeks following the closed period suggests that nutrients either weren't applied during this time (best times chosen) or that they were applied to less risky areas (best places chosen). For other periods such as late autumn and during wet summers, where storm FWM P concentrations and TP:SS ratios were high, it is recommended that an augmentation of farmer knowledge of soil drainage characteristics with local and detailed current and forecast soil moisture conditions will help to strengthen existing regulatory frameworks to avoid storm driven incidental nutrient transfers. PMID:26933967

  7. Field-based evaluation tool for riparian buffer zones in agricultural catchments.

    PubMed

    Ducros, Caroline M J; Joyce, Chris B

    2003-08-01

    Riparian buffer zones can improve water quality and enhance habitat, but a comprehensive yet rapid method that can assist the resource manager in assessing the effectiveness of buffers is not available. The aim of this paper is to describe and illustrate the use of a newly developed field-based evaluation tool for riparian buffer zones in agricultural catchments. The Buffer Zone Inventory and Evaluation Form (BZIEF) incorporates criteria-based scoring systems developed from literature review, subsequent peer-review, and then a pilot field study. Use of the BZIEF is demonstrated by comparing buffer zones in three catchments established for water quality and habitat improvement under the Water Fringe Option agrienvironment scheme in England in order to assess whether the buffers were likely to provide environmental enhancement. Results among the three catchments were generally similar; buffer zones scored highly for their abundant vegetation cover, lack of erosion, stream habitat quality, and sufficient width. Furthermore, previous grassland or arable land use did not substantially affect buffer zone ratings. However, the BZIEF indicated that inappropriate soil characteristics in one catchment were likely to constrain buffer zone effectiveness for improving water quality. In another catchment, poor riparian vegetation diversity and structure may yield ineffective habitat enhancement, according to the BZIEF. It was concluded that the BZIEF might be a useful tool for buffer zone comparison and monitoring, even though more work is needed to test and validate the method. For example, the BZIEF could be used to target appropriate locations for buffer zones and is flexible, so could be adapted for different policies, objectives and regions. PMID:14753650

  8. Modelling the effects of recent agricultural land use change on catchment flow and sediment generation

    NASA Astrophysics Data System (ADS)

    Escobar Ruiz, Veronica; Smith, Hugh; Blake, William

    2016-04-01

    Intensive agricultural practices can exacerbate runoff and soil erosion leading to detrimental impacts downstream. Physically-based models have previously been used to assess the impacts on flow and sediment transport in response to land use change, but there has been little investigation of the effect shorter-term changes linked to variations in the extent of cultivated land. The aim of this project is to quantify the impacts on flow generation and sediment transport of different catchment conditions related to both actual recent changes in agricultural land use as well as future change scenarios. To this end, a physically-based distributed hydrological model, SHETRAN was applied in the Blackwater catchment (12 km2) located in south-west England. Land cover was simulated on the basis of satellite-derived land cover maps (1990, 2000 and 2007) as well as a catchment-scale field survey (2011). Soils were represented in the model using five layers for five different soil types in which parameter values were varied in accordance with land use and literature values. Rainfall data (15 min) combined with monthly calculations of evapotranspiration using a simple temperature-based PE model were used to represent contemporary climatic conditions spanning 2010-2014. Calibration was undertaken for selected events during 2011 when land use information was concurrent with available flow and suspended sediment yield data. All land use simulations were then completed for the period 2010-2014 to enable the comparison of model outputs. This contribution will present preliminary results from these land use simulations alongside the effect of several future changes scenarios on catchment flow and sediment generation.

  9. Evaluation of nitrate removal in buffer zone supply by water from agricultural drained catchment

    NASA Astrophysics Data System (ADS)

    Fesneau, Corinne; Tournebize, Julien; Chaumont, Cedric; Guenne, Angeline

    2010-05-01

    The European Directive 2000/60/CE states objectives of a good ecological and chemical status from water body until 2015. The Cemagref project focuses on the constructed wetlands (CW) which can be used as buffer zones to lower the impact of agricultural practices on hydrosystems and decrease or even stop the transfer of contaminants via the surface waters. The experiments are carried out on a drained area where the runoff is limited and waters from the soil profile are concentrated at the drain pipes outlet. The constructed wetland studied is located at Aulnoy (77) at 70 km north-east of Paris, within the Orgeval catchment (France). Our aim is to assess the efficiency of constructed wetlands on the removal of agricultural nitrates. We are also interested in the hydrological balance of CW and agricultural catchment. The buffer zone is connected to a drained agricultural catchment of 35 hectares. The crops in the agricultural plots mainly consist in cereals (corn, maize), vegetables (horse bean, pea), sugar beet and rape. Nitrogen fertilizers are applied following normal agricultural practices. The site is monitored since 2005 for discharge and nitrate concentration in order to infer water and nitrate budgets. The buffer zone includes a pond (860m2) and a reservoir (3305 m2). The storage volume is estimated to 8000m3 which corresponds to about 10% of drainage runoff. Our study reveals potential nitrate removal because a decrease of nitrate average contents has been documented between inlet and outlet CW over a measurement period of 4 years. Average values of 57 mg/l, 40 mg/l and 27 mg/l are respectively measured at the main drain, in the pond mean and in the reservoir; that is a reduction close to 50% of nitrate fluxes. The semi-potential denitrification experiments confirm the denitrification capacity of buffer zone sediments. This constructed wetland allows the treatment of waters from agricultural drainage and provides results in line with the expectations of "good

  10. Source and transport factors influencing storm phosphorus losses in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Shore, Mairead; Jordan, Phil; Mellander, Per-Erik; kelly-quinn, Mary; Wall, David; Murphy, Paul; Melland, Alice

    2014-05-01

    The relative risk of diffuse phosphorus (P) loss from agricultural land was assessed in a well-drained arable catchment and a poorly-drained grassland catchment and in two nested basins within each catchment. This research investigated the relative control of hydrology and soil P on P losses between basins. Quick flow (QF) P losses (defined here as both concentrations and loads), monitored in stream flow during four storm events, were compared with a dynamic metric of transport risk (QF magnitude) and a static metric of critical source area (CSA) risk (extent of highly-connected poorly-drained soils with excess plant-available soil P). The potential for static transport metrics of soil connectivity and soil drainage class, to predict relative QF magnitudes and P losses between basins was also investigated. In basins with similar CSA risk but with contrasting QF magnitudes, mean TRP (total molybdate-reactive P) losses were consistently higher in the basins which had the highest QF magnitudes. This suggests that basin hydrology, rather than hydrology of high-P soils only, determined relative TRP losses between hydrologically contrasting basins. Furthermore, static transport metrics of soil connectivity and soil drainage class reliably discerned relative QF magnitudes and TRP losses between these basins. However, for two of the storm events (both occurring during the hydrologically active season), PP (particulate P) concentrations were frequently higher in basins which had the lowest QF magnitudes and may be attributed to a higher proportion of bare soil in these basins at these times as a result of their predominantly arable nature. In basins with similar hydrology, relative TRP and PP losses did not reflect trends in CSA risk or QF magnitude. The dynamics of TRP and PP losses and QF magnitude between these basins varied across storms, thus could not be predicted using static metrics. Where differences in hydrological dynamics were large, storm TRP losses were well

  11. Perception of Teachers of Agriculture about Supervised Agricultural Experience Programmes (SAEP) in Secondary Schools in Ekiti and Ondo States Nigeria

    ERIC Educational Resources Information Center

    Famiwole, Remi O.; Kolawole, E. B.

    2013-01-01

    The study investigated the perception of teachers of agriculture about Supervised Agricultural Experience Programmes (SAEP) in secondary schools in Ekiti and Ondo States. The population used for the study consisted of 520 teachers of agricultural science in all the secondary schools in Ekiti and Ondo States. The sample used for this study was 136…

  12. Identifying priority zones in an agricultural catchment to mitigate glyphosate runoff

    NASA Astrophysics Data System (ADS)

    Joris, Ingeborg; Desmet, Nele; Wilczek, Daniel; Boënne, Wesley; Seuntjens, Piet; Koopmans, Kim; Bylemans, Dany; Wouters, Katrien; Vandaele, Karel

    2015-04-01

    Pesticide concentrations in rivers generally have a very dynamic signature and are strongly dependent on time and space. The dynamic time course is due to the time- and space-variant input conditions resulting from fast overland (runoff and erosion, direct losses) and subsurface flow (artificial drainage), directly connecting surfaces and/or agricultural fields where pesticides are applied, to receiving rivers. A thorough understanding of pesticide behavior at the watershed scale is needed to increase the effectiveness of mitigation measures. We developed a method to derive priority zones for applying mitigation measures for erosion control and mitigation of glyphosate runoff in an agricultural catchment. The study catchment was selected based on results from geospatial pesticide emission modeling, historical glyphosate concentrations, and crop cover. Priority zones were derived based on a risk map which includes information about the topography, crop cover, the estimated glyphosate use, the potential erosion risk, and the connectivity of the agricultural parcels to the river. The theoretical risk map was then validated in the field using field observations of runoff during stormflow events, and observations of roads short-circuiting the runoff to the river. The validated risk map was used to define priority zones for measures related to erosion control. Suggestions for specific measures such as grass buffer strips and small dams at the field scale were made. The information will be used to target farmers that may have a significant impact on the glyphosate load to surface water. Those farmers will be encouraged to participate in a voluntary erosion control program supported by the local government. The effect of mitigation measures on the glyphosate concentrations in the river will be assessed by monitoring two years before and three years after implementation of the measures. We will present the general setup of the study and the selection methodology of the

  13. Runoff production in a small agricultural catchment in Lao PDR : influence of slope, land-use and observation scale.

    NASA Astrophysics Data System (ADS)

    Patin, J.; Ribolzi, O.; Mugler, C.; Valentin, C.; Mouche, E.

    2009-04-01

    We study the surface and sub-surface hydrology of a small agricultural catchment (60ha) located in the Luang Prabang province of Lao PDR. This catchment is representative of the rural mountainous south east Asia. It exhibits steep slopes (up to 100% and more) under a monsoon climate. After years of traditional slash and burn cultures, it is now under high land pressures due to population resettling and environment preservation policies. This evolution leads to rapid land-use changes such as shifting cultivation reduction or growing of teak forest instead of classical crops. This catchment is a benchmark site of the Managing Soil Erosion Consortium since 1998. The international consortium aims to understand the effects of agricultural changes on the catchment hydrology and soil erosion in south east Asia. The Huay Pano catchment is subdivided into small sub-catchments that are gauged and monitored. Differ- ent agricultural practices where tested along the years. At a smaller scale, plot of 1m2 are instrumented to follow runoff and detachment of soil under natural rainfall along the monsoon season. Our modeling work aims to develop a distributed hydrological model integrating experimental data at the different scales. One of the objective is to understand the impact of land-use, soil properties (slope, crust, etc) and rainfall (dry and wet seasons) on surface and subsurface flows. We present here modeling results of the runoff plot experiments (1m2 scale) performed from 2002 to 2007. The plots distribution among the catchment and over the years gives a good representativity of the different runoff responses. The role of crust, slope and land-use on runoff is examined. Finally we discuss how this plot scale will be integrated in a sub-catchment model, with a particular attention on the observed paradox: how to explain that runoff coefficients at the catchment scale are much slower than at the plot scale ?

  14. Effect of Agricultural Practices on Hydrology and Water Chemistry in a Small Irrigated Catchment, Yakima River Basin, Washington

    USGS Publications Warehouse

    McCarthy, Kathleen A.; Johnson, Henry M.

    2009-01-01

    The role of irrigation and artificial drainage in the hydrologic cycle and the transport of solutes in a small agricultural catchment in central Washington's Yakima Valley were explored using hydrologic, chemical, isotopic, age-dating, and mineralogical data from several environmental compartments, including stream water, ground water, overland flow, and streambed pore water. A conceptual understanding of catchment hydrology and solute transport was developed and an inverse end-member mixing analysis was used to further explore the effects of agriculture in this small catchment. The median concentrations of major solutes and nitrates were similar for the single field site and for the catchment outflow site, indicating that the net effects of transport processes for these constituents were similar at both scales. However, concentrations of nutrients were different at the two sites, suggesting that field-scale variations in agricultural practices as well as nearstream and instream biochemical processes are important components of agricultural chemical transformation and transport in this catchment. This work indicates that irrigation coupled with artificial drainage networks may exacerbate the ecological effects of agricultural runoff by increasing direct connectivity between fields and streams and minimizing potentially mitigating effects (denitrification and dilution, for example) of longer subsurface pathways.

  15. The effectiveness of agricultural stewardship for improving water quality at the catchment scale: Experiences from an NVZ and ECSFDI watershed

    NASA Astrophysics Data System (ADS)

    Kay, Paul; Grayson, Richard; Phillips, Martin; Stanley, Karen; Dodsworth, Alan; Hanson, Ann; Walker, Andrew; Foulger, Miles; McDonnell, Iain; Taylor, Simon

    2012-02-01

    SummaryAgriculture is estimated to be responsible for 70% of nitrate and 30-50% of phosphorus pollution, contributing to ecological and water treatment problems. Despite the fact that significant gaps remain in our understanding, it is known that agricultural stewardship can be highly effective in controlling water pollution at the plot and field scales. Knowledge at the catchment scale is, to a large extent, entirely lacking though and this is of paramount concern given that the catchment is the management unit used by regulatory authorities. The few studies that have examined the impact of agricultural stewardship at the catchment scale have found that Nitrate Vulnerable Zones (NVZs) in the UK have resulted in little improvement in water quality which concurs with the current catchment study. In addition to NVZs, there was little evidence to suggest that the England Catchment Sensitive Farming Delivery Initiative had impacted water quality and suggestions have been made for improvements, such as ensuring that stewardship measures are used in key pollution source areas and their implementation and impacts are monitored more closely. This will be essential if agricultural catchment management schemes are going to provide the benefits expected of them. Nevertheless, more intensive monitoring than that carried out by regulators showed a significant trend in decreasing winter nitrate peaks in some streams which is hypothesised to be due to recent reduced inorganic fertiliser application as a result of increasing prices. It was concluded that, collectively, these findings indicate that agricultural stewardship measures have the potential to improve water quality at the catchment scale but that voluntary schemes with insufficient financial reward or regulatory pressure are unlikely to be successful.

  16. Nutrient cycles in agricultural systems at sub-catchment scale within the UK and China

    NASA Astrophysics Data System (ADS)

    Bellarby, Jessica; Surridge, Ben; Haygarth, Philip M.; Lai, Xin; Zhang, Guilong; Song, Xiaolong; Zhou, Jianbin; Meng, Fanqiao; Shen, Jianbo; Rahn, Clive; Smith, Laurence; Burke, Sean

    2015-04-01

    Diffuse water pollution from agriculture (DWPA) represents a significant challenge in both the UK and China. The UK has developed policies and practices which seek to mitigate DWPA, yet the risks and adverse impacts of DWPA remain widespread. In contrast, China's past priorities have largely focussed on food security, with an emphasis on increasing food production through high fertiliser application rates with little attention being paid to enhanced nutrient export from land to water and to air. This has contributed to severe environmental problems which are only now beginning to be recognised and addressed. We have prepared nutrient balances (phosphorus and nitrogen) in contrasting agricultural production systems at sub-catchment scale within China and the UK. These draw from a variety of sources ranging from general yearly statistics collected by the respective government to farm surveys. Our aim is to use the resulting nutrient balances to underpin the sharing of knowledge and innovation to mitigate DWPA in both nations. In the UK, the case studies focus on the three Demonstration Test Catchment locations, covering a range of livestock and arable production systems across England. Here, the high frequency monitoring of phosphorus river loads enables the cross-validation of the simple nutrient budget approaches applied in this study. In China, our case studies span kiwi orchard, fruit and vegetable solar greenhouse systems, double cropped rice-wheat and wheat-maize production systems. Substantial differences in nutrient stocks and flows exist between individual production systems both across and within the two countries. These differences will be expressed along the source-mobilisation-delivery-impact continuum that underpins our budgets for both phosphorus and nitrogen. We will present the phosphorus cycles of some case studies and highlight their challenges and relevance at sub-catchment scale. Based on our nutrient budgets, general recommendations can be

  17. Managing the drinking water catchment areas: the French agricultural cooperatives feed back.

    PubMed

    Charrière, Séverine; Aumond, Claire

    2016-06-01

    The quality of raw water is problematic in France, largely polluted by nitrates and pesticides (Mueller and Helsel, Nutrients in the nation's waters-too much of a good thing? Geological Survey (U.S.), 1996; European Environment Agency, European waters-assessment of status and pressures, 2012).This type of pollution, even though not always due to agriculture (example of the catchment of Ambleville, county 95, France where the nitrate pollution is mainly due to sewers (2012)), has been largely related to the agricultural practices (Sci Total Environ 407:6034-6043, 2009).Taking note of this observation, and instead of letting it paralyze their actions, the agricultural cooperatives decided with Agrosolutions to act directly on the field with their subscribers to change the agricultural practices impacting the water and the environment.This article shows how the French agricultural cooperatives transformed the awareness of the raw water quality problem into an opportunity for the development and implementation of more precise and responsible practices, to protect their environment. They measure in order to pilot, co-construct and build the best action plans possible according to the three pillars of environment, economy and agronomy. PMID:27074925

  18. A palaeolimnological investigation into nutrient impact and recovery in an agricultural catchment.

    PubMed

    O'Dwyer, Barry; Crockford, Lucy; Jordan, Phil; Hislop, Lindsay; Taylor, David

    2013-07-30

    Widespread deterioration in water quality as a result of anthropogenic activity has led to the development and implementation of measures aimed at the protection of water resources in the EU. To date, however, relatively little attention has been paid to the effectiveness of these measures. Evidence from an enrichment-sensitive lake permitted reconstructions of changes in ecological and chemical water quality over the last c. 150-200 years, a period that includes a mid to late 20th century intensification of agriculture that was widely experienced across the European Union and the subsequent implementation of measures aimed at protecting water resources against pollution from farming. The data show the development of a more nutrient-tolerant diatom community from early in the 20th century, while the main trophic changes occurred from the 1950s, with the site becoming eutrophic by the 1960s. Heightened enrichment is thought to be linked to enhanced levels of phosphorus (P) transfers from the surrounding grassland catchment owing to an intensification of agricultural activities locally. Most recently, since the late 1990s and particularly post-2007, evidence suggests a decrease in aquatic enrichment, despite continued increases in agricultural intensification. This decoupling is likely to mark a successful implementation in 2006 of measures aimed at decreasing diffuse nutrient transfers from catchments linked to agri-environmental policies in Europe. The research highlights the importance of enrichment-sensitive water bodies as sentinel sites in the monitoring of both external and internal nutrient loadings as agricultural activities and other pressures change within the context of implementing regulatory responses to earlier declines in water quality. PMID:23490624

  19. Water ponding and catchment runoff as influenced by conservation agriculture in May Zeg-zeg (Ethiopia)

    NASA Astrophysics Data System (ADS)

    Lanckriet, Sil; Nyssen, Jan; Araya, Tesfay; Poesen, Jean; Govaerts, Bram; Bauer, Hans; Deckers, Jozef; Haile, Mitiku; Verfaillie, Els; Cornelis, Wim M.

    2013-04-01

    This study evaluates the practice of conservation agriculture (CA) in the May Zeg-zeg catchment (MZZ; 187 ha) in the North Ethiopian Highlands as a soil management technique for reducing soil loss and runoff, and assesses the consequences of future large-scale implementation on soil and hydrology at catchment-level. The study of such practice is important especially under conditions of climate change, since EdGCM (Educational Global Climate Model) simulation predicts by 2040 an increase in precipitation by more than 100 mm yr-1 in the study area. Firstly, field-saturated infiltration rates, together with soil texture and soil organic carbon contents, were measured. Relation with local topography allows to generate a pedotransfer function for field-saturated infiltration rate, and spatial interpolation with Linear Regression Mapping was used to map field-saturated infiltration rates optimally within the catchment. Secondly, on several farmlands, CA was checked against Plain Tillage (PT) for values of field-saturated infiltration rates, soil organic carbon, runoff and soil loss. Results show no significant differences for infiltration rates but significant differences for runoff and soil loss (as measured in the period 2005-2011). Runoff coefficients were 30.4% for PT and 18.8% for CA; soil losses were 35.4 t ha-1 yr-1 for PT and 14.4 t ha-1 yr-1 for CA. Thirdly, all collected information was used to predict future catchment hydrological response for full-implementation of CA under the predicted wetter climate (simulation with EdGCM). Curve Numbers for farmlands with CA were calculated. An area-weighted Curve Number allows the simulation of the 2011 rainy season runoff, predicting a total runoff depth of 23.5 mm under CA and 27.9 mm under PT. Furthermore, the Revised Universal Soil Loss Equation management factor P was calibrated for CA. Results also show the important influence of increased surface roughness on water ponding, modeled with a hydrologic conservation

  20. Deriving a per-field land use and land cover map in an agricultural mosaic catchment

    NASA Astrophysics Data System (ADS)

    Seo, B.; Bogner, C.; Poppenborg, P.; Martin, E.; Hoffmeister, M.; Jun, M.; Koellner, T.; Reineking, B.; Shope, C. L.; Tenhunen, J.

    2014-09-01

    Detailed data on land use and land cover constitute important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly; however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in the agricultural mosaic catchment Haean in South Korea. We recorded the land cover types with additional information on agricultural practice. In this paper we introduce the data, their collection and the post-processing protocol. Furthermore, because it is important to quantitatively evaluate available land use and land cover products, we compared our data with the MODIS Land Cover Type product (MCD12Q1). During the studied period, a large portion of dry fields was converted to perennial crops. Compared to our data, the forested area was underrepresented and the agricultural area overrepresented in MCD12Q1. In addition, linear landscape elements such as waterbodies were missing in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research. The data are available at the public repository Pangaea (doi:110.1594/PANGAEA.823677).

  1. Predicting microbial water quality with models: Over-arching questions for managing risk in agricultural catchments.

    PubMed

    Oliver, David M; Porter, Kenneth D H; Pachepsky, Yakov A; Muirhead, Richard W; Reaney, Sim M; Coffey, Rory; Kay, David; Milledge, David G; Hong, Eunmi; Anthony, Steven G; Page, Trevor; Bloodworth, Jack W; Mellander, Per-Erik; Carbonneau, Patrice E; McGrane, Scott J; Quilliam, Richard S

    2016-02-15

    The application of models to predict concentrations of faecal indicator organisms (FIOs) in environmental systems plays an important role for guiding decision-making associated with the management of microbial water quality. In recent years there has been an increasing demand by policy-makers for models to help inform FIO dynamics in order to prioritise efforts for environmental and human-health protection. However, given the limited evidence-base on which FIO models are built relative to other agricultural pollutants (e.g. nutrients) it is imperative that the end-user expectations of FIO models are appropriately managed. In response, this commentary highlights four over-arching questions associated with: (i) model purpose; (ii) modelling approach; (iii) data availability; and (iv) model application, that must be considered as part of good practice prior to the deployment of any modelling approach to predict FIO behaviour in catchment systems. A series of short and longer-term research priorities are proposed in response to these questions in order to promote better model deployment in the field of catchment microbial dynamics. PMID:26657248

  2. Deriving a per-field land use and land cover map in an agricultural mosaic catchment

    NASA Astrophysics Data System (ADS)

    Seo, B.; Bogner, C.; Poppenborg, P.; Martin, E.; Hoffmeister, M.; Jun, M.; Koellner, T.; Reineking, B.; Shope, C. L.; Tenhunen, J.

    2014-04-01

    Detailed data on land use and land cover constitutes important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly, however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in an agricultural mosaic catchment Haean, South Korea. We recorded the land cover types with additional information on agricultural practice and make this data available at the public repository Pangaea (doi:10.1594/PANGAEA.823677). In this paper we introduce the data, its collection and the post-processing protocol. During the studied period, a large portion of dry fields was converted to perennial crops. A comparison between our dataset and MODIS Land Cover Type (MCD12Q1) suggested that the MODIS product was restricted in this area since it does not distinguish irrigated fields from general croplands. In addition, linear landscape elements such as water bodies were not detected in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research.

  3. Legacies and Trajectories of Hormone Export from Agricultural Catchments Under Natural and Anthropogenic Drivers

    NASA Astrophysics Data System (ADS)

    Gall, H. E.; Mashtare, M. L.; Sassman, S. A.; Rao, P. C.; Thompson, S. E.; Basu, N. B.; Lee, L. S.

    2011-12-01

    Hormones and other emerging contaminants have been detected in surface waters worldwide at concentrations known to negatively impact sensitive aquatic species. Concentrated animal feeding operations (CAFOs) are a significant source of hormones to the environment, as their recent intensification has increased manure production and land disposal. However, little is known regarding the short- and long-term fate and transport in catchments and likely environmental impacts. Lab microcosm and column studies indicate moderately high retardation (log KOC ~ 2.8 - 3.7) and fast aerobic biotransformation (half-lives < 10 days), yet monitoring reveals consistent presence of hormones in streams. Field studies at nested scales in tile-drained agricultural catchments suggested time-invariant concentrations for hormone export at annual time scales, similar to that noted for nutrients, implying accumulation of legacy stores from annual manure applications. A robust hydro-biogeochemical model, Hormone Export and Restoration Dynamics (HERD), was developed and validated to probe several research questions: (i) can manure application practices lead to the accumulation of hormones within the soil profile and develop legacy sources?; (ii) how persistent are hormones when long-term manure applications cease?; and (iii) to what extent can best management practices be successfully employed to reduce the downstream export of hormones? Preliminary HERD simulations suggest that hormones build up in the soil profile over time as a result of repeated animal waste applications, creating legacy sources that cause hormone export to become mass transfer-limited rather than source-limited. Under such conditions, annual flow-weighted concentrations were found to be chemostatic, implying hydrologic variability rather than biogeochemical processes as the dominant control of hormone export. Additionally, these results suggest that long-term, repeated animal waste applications can lead to chronic exposure

  4. Development and implementation of the Norwegian monitoring programme for agricultural landscapes.

    PubMed

    Dramstad, W E; Fjellstad, W J; Strand, G H; Mathiesen, H F; Engan, G; Stokland, J N

    2002-01-01

    This paper describes the development and implementation of the Norwegian monitoring programme for agricultural landscapes--the '3Q programme'. The main objective of the scheme is to indicate development trends in the agricultural landscape, and their consequences for spatial structure, biodiversity, cultural heritage and accessibility. The monitoring programme aims to give policy feedback and provide data to fulfill international reporting requirements. This paper describes the background to the programme and reasons behind the choice of methods. Results are presented to show the accuracy of the methods employed and the range of indicator values recorded in the programme. Strengths and limitations of the monitoring programme are discussed, and potential future improvements and developments are outlined. Although there remains a potential for methodological improvement, we stress the importance of establishing a baseline to enable the detection of development trends in a rapidly changing environment. PMID:11876074

  5. Re-examining the basis for source discrimination and data corrections used by sediment fingerprinting studies in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Smith, Hugh; Blake, Will

    2014-05-01

    The sediment fingerprinting technique has been widely used in agricultural catchments to quantify fine sediment contributions from various land use sources. This application of the technique depends on the key assumption that land-use source signatures imprinted on catchment soils are decipherable from those due to other landscape factors affecting soil and sediment properties. We re-examine this key assumption by investigating (i) the physical and chemical basis for source discrimination and (ii) potential factors that may confound source un-mixing in agricultural catchments, including particle size and organic matter effects on tracer properties. The study is situated in the River Tamar, a predominantly agricultural catchment in south-west England that has also been affected by mining. Source discrimination focused on pasture and cultivated land uses and channel banks. Monthly, time-integrated suspended sediment samples were collected across seven catchments for a 12-month period. Physical and chemical properties measured in source soils and sediment included fallout radionuclides, major and minor element geochemical constituents, total organic carbon and particle size. Source discrimination was entirely dependent on differences in tracer property concentrations between surface and sub-surface soils. This is based on fallout radionuclide concentrations that are surface-elevated, while many geochemical properties are surface-depleted due to weathering and pedogenetic effects, although surface soil contamination can reverse this trend. Source discrimination in the study catchments was limited by (i) rotation of cultivated and pasture fields resulting in reduced differences between these two sources and (ii) the cultivated source signature resembling a mix of the pasture and channel bank sources for many tracer properties. Furthermore, metal pollution from abandoned historic mines and organic enrichment of sediment from areas of peaty soil resulted in the non

  6. Dynamics of nitrate and chloride during storm events in agricultural catchments with different subsurface drainage intensity (Indiana, USA)

    NASA Astrophysics Data System (ADS)

    Kennedy, Casey D.; Bataille, Clement; Liu, Zhongfang; Ale, Srinivasulu; VanDeVelde, Justin; Roswell, Charles R.; Bowling, Laura C.; Bowen, Gabriel J.

    2012-10-01

    SummaryDrainage tiles buried beneath many naturally poorly drained agricultural fields in the Midwestern U.S. are believed to "short circuit" pools of NO3--laden soil water and shallow groundwater directly into streams that eventually discharge to the Mississippi River. Although much is known about the mechanisms controlling this regionally pervasive practice of artificial drainage at the field-plot scale, an integrative assessment of the effect of drainage density (i.e., the number of tile drains per unit area) on the transport of nutrients and solutes in streams at the catchment scale is lacking. In this study, we quantified the flux and hydrological pathways of agricultural NO3- and road-salt Cl- from catchments lying within the Wabash River Basin, a major source of NO3- to the Mississippi River. The paired catchments differ primarily in drainage density (70% vs. 31%, by catchment area), with essentially all other agricultural management, land use, and soil drainage characteristics remaining equal. Our study revealed two significant hydrological responses to increased drainage density: (1) more near-surface storm event water (dilute in both NO3- and Cl) was transported early in the storm and (2) higher transport of Cl--laden pre-event soil water relative to shallow groundwater elevated in NO3- occurred later in the storm. These patterns are consistent with a proposed conceptual model in which increased drainage density results in (1) greater transport of soil water to streams and (2) a delayed rise in the water table. With respect to nutrient management implications, these results indicate that increased drainage density impacts subsurface pools of Cl- and NO3- differently, a finding that we propose is linked to soil/ground water dynamics in artificially drained agricultural catchments.

  7. Using continuous monitoring of physical parameters to better estimate phosphorus fluxes in a small agricultural catchment

    NASA Astrophysics Data System (ADS)

    Minaudo, Camille; Dupas, Rémi; Moatar, Florentina; Gascuel-Odoux, Chantal

    2016-04-01

    Phosphorus fluxes in streams are subjected to high temporal variations, questioning the relevance of the monitoring strategies (generally monthly sampling) chosen to assist EU Directives to capture phosphorus fluxes and their variations over time. The objective of this study was to estimate the annual and seasonal P flux uncertainties depending on several monitoring strategies, with varying sampling frequencies, but also taking into account simultaneous and continuous time-series of parameters such as turbidity, conductivity, groundwater level and precipitation. Total Phosphorus (TP), Soluble Reactive Phosphorus (SRP) and Total Suspended Solids (TSS) concentrations were surveyed at a fine temporal frequency between 2007 and 2015 at the outlet of a small agricultural catchment in Brittany (Naizin, 5 km2). Sampling occurred every 3 to 6 days between 2007 and 2012 and daily between 2013 and 2015. Additionally, 61 storms were intensively surveyed (1 sample every 30 minutes) since 2007. Besides, water discharge, turbidity, conductivity, groundwater level and precipitation were monitored on a sub-hourly basis. A strong temporal decoupling between SRP and particulate P (PP) was found (Dupas et al., 2015). The phosphorus-discharge relationships displayed two types of hysteretic patterns (clockwise and counterclockwise). For both cases, time-series of PP and SRP were estimated continuously for the whole period using an empirical model linking P concentrations with the hydrological and physic-chemical variables. The associated errors of the estimated P concentrations were also assessed. These « synthetic » PP and SRP time-series allowed us to discuss the most efficient monitoring strategies, first taking into account different sampling strategies based on Monte Carlo random simulations, and then adding the information from continuous data such as turbidity, conductivity and groundwater depth based on empirical modelling. Dupas et al., (2015, Distinct export dynamics for

  8. Scaling issues relating to phosphorus transfer from land to water in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Brazier, R. E.; Heathwaite, A. L.; Liu, S.

    2005-03-01

    Various scales of input data exist to parameterise diffuse pollution models for the UK. For screening methodologies such as the phosphorus indicators tool—PIT [Heathwaite, A.L., Sharpley, A.N., Bechmann, M., 2003a. The conceptual basis for a decision support framework to assess the risk of phosphorus loss at the field scale across Europe. Journal of Plant Nutrition and Soil Science 166, 1-12; Heathwaite, A.L., Burke, S., Quinn, P.F., 2003b. The nutrient export risk matrix (the NERM) for strategic application of biosolids to agricultural land. International Association for Hydrological Sciences Publication 285, 1-9], which is applied throughout England and Wales, some assessment of the implications of using input data derived at different scales must be made. This work is further driven by practical issues such as licensing costs and data availability, which mean that not all data are readily accessible for all end users. This paper represents a first step towards quantifying the 'value-added' to model predictions by using input data derived at three different scales: 50×50 m, 1×1 km and 5×5 km. Model runs using PIT were carried out against observed phosphorus water quality data from the River Start and River Gara, which are the main sub-catchments of Slapton Ley, a grade 1 National Nature Reserve in southwest England. Model runs for the main 46 km 2 Slapton catchment were also undertaken. The results show that some improvement in the ability of the model to capture the observed water quality behaviour may be made by using higher resolution DEM data, though these improvements may be outweighed by the extra data processing and computational time. Conversely, model runs driven by the 5 km data demonstrate consistent under-prediction for all three test catchments, which is perhaps not surprising given the greater degree of averaging underlying datasets at this scale. Results from the 1 km datasets provide the best agreement with observed water quality data, and

  9. Understanding the controls on deposited fine sediment in the streams of agricultural catchments.

    PubMed

    Naden, P S; Murphy, J F; Old, G H; Newman, J; Scarlett, P; Harman, M; Duerdoth, C P; Hawczak, A; Pretty, J L; Arnold, A; Laizé, C; Hornby, D D; Collins, A L; Sear, D A; Jones, J I

    2016-03-15

    Excessive sediment pressure on aquatic habitats is of global concern. A unique dataset, comprising instantaneous measurements of deposited fine sediment in 230 agricultural streams across England and Wales, was analysed in relation to 20 potential explanatory catchment and channel variables. The most effective explanatory variable for the amount of deposited sediment was found to be stream power, calculated for bankfull flow and used to index the capacity of the stream to transport sediment. Both stream power and velocity category were highly significant (p ≪ 0.001), explaining some 57% variation in total fine sediment mass. Modelled sediment pressure, predominantly from agriculture, was marginally significant (p<0.05) and explained a further 1% variation. The relationship was slightly stronger for erosional zones, providing 62% explanation overall. In the case of the deposited surface drape, stream power was again found to be the most effective explanatory variable (p<0.001) but velocity category, baseflow index and modelled sediment pressure were all significant (p<0.01); each provided an additional 2% explanation to an overall 50%. It is suggested that, in general, the study sites were transport-limited and the majority of stream beds were saturated by fine sediment. For sites below saturation, the upper envelope of measured fine sediment mass increased with modelled sediment pressure. The practical implications of these findings are that (i) targets for fine sediment loads need to take into account the ability of streams to transport/retain fine sediment, and (ii) where agricultural mitigation measures are implemented to reduce delivery of sediment, river management to mobilise/remove fines may also be needed in order to effect an improvement in ecological status in cases where streams are already saturated with fines and unlikely to self-cleanse. PMID:26789373

  10. A Lowland Catchment Response to Heavy Agricultural Nitrogen Loads Explained with a Multiple Isotope and Hydrochemical Approach

    NASA Astrophysics Data System (ADS)

    Wexler, S. K.; Hiscock, K. M.; Dennis, P.

    2009-12-01

    East Anglia, UK, is a lowland area of intensive agriculture, producing much of the UK’s arable crops, while also supporting some of Europe’s most sensitive wetland habitats. The River Wensum in East Anglia is a calcareous lowland river with Site of Special Scientific Interest status. Within the catchment Special Areas of Conservation have been designated (EU Habitats Directive). The river supplies the city of Norwich with its drinking water (population 120 000), while downstream of Norwich water from the Wensum flows through the Norfolk Broads, a unique and protected wetland habitat, to enter the North Sea at Great Yarmouth. The Wensum catchment, covering an area of 570 km2, is heavily impacted by agricultural activity with a high nutrient load that affects both the underlying Cretaceous Chalk aquifer and the groundwater-dependent river, which has a base flow index of 0.78. Nitrate concentrations exceed the legal limit in places (up to 85 mg/ L). In this study, river, tributary, drain and groundwater samples from the Wensum catchment were collected over 27 months from February 2007, through all seasons and flow conditions, alongside samples of fertiliser, manure, waste water, precipitation and dry deposition. The nitrogen and oxygen isotopic composition of nitrate was analysed using the denitrifier method to understand nitrogen transport and cycling within the catchment. Water isotopes were used as an additional tracer, with major ion and trace element hydrochemistry. There is evidence of significant natural attenuation of nitrate which occurs in different locations and at varying rates within the catchment hydrology. Baseflow from highly impacted Chalk groundwater in the valley, with the lowest nitrate isotope ratios and highest concentration of catchment waters, is partially denitrified as it passes through a thick gravel hyporheic zone. Nitrate in surface drainage water undergoes assimilation and denitrification as it infiltrates through the soil and

  11. Assessing the impacts of sustainable agricultural practices for water quality improvements in the Vouga catchment (Portugal) using the SWAT model.

    PubMed

    Rocha, João; Roebeling, Peter; Rial-Rivas, María Ermitas

    2015-12-01

    The extensive use of fertilizers has become one of the most challenging environmental issues in agricultural catchment areas. In order to reduce the negative impacts from agricultural activities and to accomplish the objectives of the European Water Framework Directive we must consider the implementation of sustainable agricultural practices. In this study, we assess sustainable agricultural practices based on reductions in N-fertilizer application rates (from 100% to 0%) and N-application methods (single, split and slow-release) across key agricultural land use classes in the Vouga catchment, Portugal. The SWAT model was used to relate sustainable agricultural practices, agricultural yields and N-NO3 water pollution deliveries. Results show that crop yields as well as N-NO3 exportation rates decrease with reductions in N-application rates and single N-application methods lead to lower crop yields and higher N-NO3 exportation rates as compared to split and slow-release N-application methods. PMID:26196068

  12. Catchments Under Change: Assessing Impacts and Feedbacks from New Biomass Crops in the Agricultural Midwestern USA

    NASA Astrophysics Data System (ADS)

    Yaeger, Mary; Housh, Mashor; Ng, Tze Ling; Cai, Ximing; Sivapalan, Murugesu

    2013-04-01

    In order to meet the challenges of future change, it is essential to understand the environmental response to current conditions and historical changes. The central Midwestern US is an example of anthropogenic change and environmental feedbacks, having been transformed from a natural grassland system to an artificially-drained agricultural system. Environmental feedbacks from reduced soil residence times coupled with increasing crop fertilization have manifested as a hypoxic zone in the Gulf of Mexico. In an effort to address these feedbacks while meeting new crop demands, large-scale planting of high-yielding perennial biomass crops has been proposed. This could be detrimental to both human and environmental streamflow users because these plants require more water than do current crops. The lowest natural flows in this shallow groundwater-dependent region coincide with the peak of the growing season, thus compounding the problem. Therefore, for large-scale biomass crop production to be sustainable, these tradeoffs between water quality and water quantity must be fully understood. To better understand the catchment response to current conditions, we have analyzed streamflow data in a central Illinois agricultural watershed. To deal with future changes, we have developed an integrated systems model which provides, among other outputs, the land usage that maximizes the benefit to the human system. This land use is then implemented in a separate hydrologic model to determine the impact to the environmental system. Interactively running the two models, taking into account the catchment response to human actions as well as possible anthropogenic responses to the environment, allows us to examine the feedbacks between the two systems. This lets us plot the trajectory of the state of the system, which we hypothesize will show emergent internal properties of the coupled system. Initial tests of this modeling framework show promise that this may indeed be the case. External

  13. Suspended sediment export in five intensive agricultural river catchments with contrasting land use and soil drainage characteristics

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie; Rowan, John; Melland, Alice; Jordan, Phil; Fenton, Owen; hUallacháin, Daire Ó.

    2015-04-01

    Soil erosion and sediment loss from land can have a negative impact on the chemical and ecological quality of freshwater resources. In catchments dominated by agriculture, prediction of soil erosion risk is complex due to the interaction of physical characteristics such as topography, soil erodibility, hydrological connectivity and climate. Robust measurement approaches facilitate the assessment of sediment loss magnitudes in relation to a range of agricultural settings. These approaches improve our understanding of critical sediment transfer periods and inform development of evidence-based and cost-effective management strategies. The aim of this study was to i) assess the efficacy of out-of-channel (ex-situ) suspended sediment measurement approaches, ii) to quantify the variability of sediment exported from five river catchments with varying hydrology and agricultural land uses over multiple years and iii) to investigate trends in relation to physical and land use characteristics when sediment data were compared between catchments. Sediment data were collected in five intensive agricultural river catchments in Ireland (3-11 km2) which featured contrasting land uses (predominantly intensive grassland or arable) and soil drainage classes (well, moderate and poor). High-resolution suspended sediment concentration data (SSC - using a calibrated turbidity proxy) were collected ex-situ and combined with in-stream discharge data measured at each catchment outlet to estimate suspended sediment yield (SSY - t km-2 yr-1). In two catchments additional in-stream turbidity monitoring equipment replicated ex-situ measurements including site specific calibration of individual in-stream and ex-situ turbidity probes. Depth-integrated samples were collected to assess the accuracy of both approaches. Method comparison results showed that true SSC values (from depth-integrated sampling) were predominantly within the 95% confidence interval of ex-situ predicted SSC consequently

  14. A view of annual water quality cycle and inter-annual variations in agricultural headwater catchment (Kervidy-Naizin, France)

    NASA Astrophysics Data System (ADS)

    Aubert, A.; Gascuel-odoux, C.; Merot, P.; Grimaldi, C.; Gruau, G.; Ruiz, L.

    2011-12-01

    Climatic conditions impact biotransformation and transfer of solutes. Therefore, they modify solute emissions in streams. Studying these modifications requires long term and detailed monitoring of both internal processes and river loads, which are rarely combined. The Kervidy-Naizin catchment, implemented in 1993, is part of the French network of catchment for environmental research (SOERE RBV, focused on the Critical Zone). It is an intensive agricultural catchment located in a temperate climate in Western France (Brittany) (Molenat et al., 2008; Morel et al., 2009). It presents shallow aquifers due to impervious bedrock. Both hydrology and water chemistry are monitored with a daily time step since 2000-01, as well as possible explanatory data (land use, meteorology, etc.). Concentrations in major anions in this catchment are extremely high, which make people call it a "saturated" catchment. We identified annual patterns for chloride, sulphate, dissolved organic and inorganic carbon and nitrate concentration variations. First, we considered the complete set of concentration data as function of the time. From that, we foresaw 3 cyclic temporal patterns. Then, from representing the concentrations as function of meteorological parameters, intra-annual hysteretic variations and their inter-annual variations were clearly identified. Our driving question is to know if and how climatic conditions are responsible for variations of the patterns in and between years. In winter, i.e. rainy and cold period, rainfall is closely linked to discharge because of a direct recharge to the shallow groundwater. Reversely, in transition periods (spring and fall) and hot periods, both rainfall and temperature influences discharge in relation to their range of variations. Moreover, biological processes, driven by temperature and wetness, also act during these periods. On the whole, we can emphasize the specificity of water chemistry patterns for each element. Noticeable differences

  15. USE OF MACROINVERTEBRATE METRICS TO DIFFERENTIATE BETWEEN THE EFFECTS OF DECREASED CANOPY AND INCREASED EMBEDDEDNESS IN STREAMS IN DRAINING AGRICULTURAL CATCHMENTS

    EPA Science Inventory

    Reduced canopy as a result of lost riparian vegetation and increased substrate embeddedness as a result of greater inputs of the fine sediments are two environmental stressor gradients that often covary in streams draining agricultural catchments. An understanding of relationship...

  16. Impacts of agricultural phosphorus use in catchments on shallow lake water quality: About buffers, time delays and equilibria.

    PubMed

    Schippers, Peter; van de Weerd, Hendrika; de Klein, Jeroen; de Jong, Barend; Scheffer, Marten

    2006-10-01

    Phosphorus (P) losses caused by intensive agriculture are known to have potentially large negative effects on the water quality of lakes. However, due to the buffering capacity of soils and lake ecosystems, such effects may appear long after intensive agriculture started. Here we present the study of a coupled shallow lake catchment model, which allows a glimpse of the magnitude of these buffer-related time delays. Results show that the buffering capacity of the lake water was negligible whereas buffering in the lake sediment postponed the final lake equilibrium for several decades. The surface soil layer in contact with runoff water was accountable for a delay of 5-50 years. The most important buffer, however, was the percolation soil layer that may cause a delay of 150-1700 years depending on agricultural P surplus levels. Although the buffers could postpone final lake equilibria for a considerable time, current and target agricultural surplus levels eventually led to very turbid conditions with total P concentrations of 2.0 and 0.6 mg L(-1) respectively. To secure permanent clear water states the current agricultural P surplus of 15 kg P ha(-1) yr(-1) should drop to 0.7 kg P ha(-1) yr(-1). We present several simple equations that can be used to estimate the sustainable P surplus levels, buffer related time delays and equilibrium P concentrations in other catchment-lake systems. PMID:16781763

  17. Using lumped modelling for providing simple metrics and associated uncertainties of catchment response to agricultural-derived nitrates pollutions

    NASA Astrophysics Data System (ADS)

    RUIZ, L.; Fovet, O.; Faucheux, M.; Molenat, J.; Sekhar, M.; Aquilina, L.; Gascuel-odoux, C.

    2013-12-01

    The development of simple and easily accessible metrics is required for characterizing and comparing catchment response to external forcings (climate or anthropogenic) and for managing water resources. The hydrological and geochemical signatures in the stream represent the integration of the various processes controlling this response. The complexity of these signatures over several time scales from sub-daily to several decades [Kirchner et al., 2001] makes their deconvolution very difficult. A large range of modeling approaches intent to represent this complexity by accounting for the spatial and/or temporal variability of the processes involved. However, simple metrics are not easily retrieved from these approaches, mostly because of over-parametrization issues. We hypothesize that to obtain relevant metrics, we need to use models that are able to simulate the observed variability of river signatures at different time scales, while being as parsimonious as possible. The lumped model ETNA (modified from[Ruiz et al., 2002]) is able to simulate adequately the seasonal and inter-annual patterns of stream NO3 concentration. Shallow groundwater is represented by two linear stores with double porosity and riparian processes are represented by a constant nitrogen removal function. Our objective was to identify simple metrics of catchment response by calibrating this lumped model on two paired agricultural catchments where both N inputs and outputs were monitored for a period of 20 years. These catchments, belonging to ORE AgrHys, although underlain by the same granitic bedrock are displaying contrasted chemical signatures. The model was able to simulate the two contrasted observed patterns in stream and groundwater, both on hydrology and chemistry, and at the seasonal and pluri-annual scales. It was also compatible with the expected trends of nitrate concentration since 1960. The output variables of the model were used to compute the nitrate residence time in both the

  18. Quantifying sediment sources in a lowland agricultural catchment pond using (137)Cs activities and radiogenic (87)Sr/(86)Sr ratios.

    PubMed

    Le Gall, Marion; Evrard, Olivier; Foucher, Anthony; Laceby, J Patrick; Salvador-Blanes, Sébastien; Thil, François; Dapoigny, Arnaud; Lefèvre, Irène; Cerdan, Olivier; Ayrault, Sophie

    2016-10-01

    Soil erosion often supplies high sediment loads to rivers, degrading water quality and contributing to the siltation of reservoirs and lowland river channels. These impacts are exacerbated in agricultural catchments where modifications in land management and agricultural practices were shown to accelerate sediment supply. In this study, sediment sources were identified with a novel tracing approach combining cesium ((137)Cs) and strontium isotopes ((87)Sr/(86)Sr) in the Louroux pond, at the outlet of a lowland cultivated catchment (24km(2), Loire River basin, France) representative of drained agricultural areas of Northwestern Europe. Surface soil (n=36) and subsurface channel bank (n=17) samples were collected to characterize potential sources. Deposited sediment (n=41) was sampled across the entire surface of the pond to examine spatial variation in sediment deposits. In addition, a 1.10m sediment core was sampled in the middle of the pond to reconstruct source variations throughout time. (137)Cs was used to discriminate between surface and subsurface sources, whereas (87)Sr/(86)Sr ratios discriminated between lithological sources. A distribution modeling approach quantified the relative contribution of these sources to the sampled sediment. Results indicate that surface sources contributed to the majority of pond (μ 82%, σ 1%) and core (μ 88%, σ 2%) sediment with elevated subsurface contributions modeled near specific sites close to the banks of the Louroux pond. Contributions of the lithological sources were well mixed in surface sediment across the pond (i.e., carbonate sediment contribution, μ 48%, σ 1% and non-carbonate sediment contribution, μ 52%, σ 3%) although there were significant variations of these source contributions modeled for the sediment core between 1955 and 2013. These fluctuations reflect both the progressive implementation of land consolidation schemes in the catchment and the eutrophication of the pond. This original sediment

  19. Mitigation scenario analysis: modelling the impacts of changes in agricultural management practices on surface water quality at the catchment scale

    NASA Astrophysics Data System (ADS)

    Taylor, Sam; He, Yi; Hiscock, Kevin

    2014-05-01

    Increasing human pressures on the natural environment through the demand for increased agricultural productivity have exacerbated and deteriorated water quality conditions within many environments due to an unbalancing of the nutrient cycle. As a consequence, increased agricultural diffuse water pollution has resulted in elevated concentrations of nutrients within surface water and groundwater bodies. This deterioration in water quality has direct consequences for the health of aquatic ecosystems and biodiversity, human health, and the use of water as a resource for public water supply and recreation. To mitigate these potential impacts and to meet commitments under the EU Drinking Water and Water Framework Directives, there is a need to improve our understanding of the impacts that agricultural land use and management practices have on water quality. Water quality models are one of the tools available which can be used to facilitate this aim. These simplified representations of the physical environment allow a variety of changes to be simulated within a catchment, including for example changes in agricultural land use and management practices, allowing for predictions of the impacts of those measures on water quality to be developed and an assessment to be made of their effectiveness in improving conditions. The aim of this research is to apply the water quality model SWAT (Soil and Water Assessment Tool) to the Wensum catchment (area 650 km2), situated in the East of England, to predict the impacts of potential changes in land use and land management practices on water quality as part of a process to select those measures that in combination will have the greatest potential to improve water quality. Model calibration and validation is conducted at three sites within the catchment against observations of river discharge and nitrate and total phosphorus loads at a monthly time-step using the optimisation algorithm SUFI-2 (Sequential Uncertainty Fitting Version 2

  20. Spatio-temporal analysis of discharge regimes based on hydrograph classification techniques in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Chen, Xiaofei; Bloeschl, Guenter; Blaschke, Alfred Paul; Silasari, Rasmiaditya; Exner-Kittridge, Mike

    2016-04-01

    The stream, discharges and groundwater hydro-graphs is an integration in spatial and temporal variations for small-scale hydrological response. Characterizing discharges response regime in a drainage farmland is essential to irrigation strategies and hydrologic modeling. Especially for agricultural basins, diurnal hydro-graphs from drainage discharges have been investigated to achieve drainage process inferences in varying magnitudes. To explore the variability of discharge responses, we developed an impersonal method to characterize and classify discharge hydrograph based on features of magnitude and time-series. A cluster analysis (hierarchical k-means) and principal components analysis techniques are used for discharge time-series and groundwater level hydro-graphs to analyze their event characteristics, using 8 different discharge and 18 groundwater level hydro-graphs to test. As the variability of rainfall activity, system location, discharge regime and soil moisture pre-event condition in the catchment, three main clusters of discharge hydro-graph are identified from the test. The results show that : (1) the hydro-graphs from these drainage discharges had similar shapes but different magnitudes for individual rainstorm; the similarity is also showed in overland flow discharge and spring system; (2) for each cluster, the similarity of shape insisted, but the rising slope are different due to different antecedent wetness condition and the rain accumulation meanwhile the difference of regression slope can be explained by system location and discharge area; and (3) surface water always has a close proportional relation with soil moisture throughout the year, while only after the soil moisture exceeds a certain threshold does the outflow of tile drainage systems have a direct ratio relationship with soil moisture and a inverse relationship with the groundwater levels. Finally, we discussed the potential application of hydrograph classification in a wider range of

  1. Monitoring of soil moisture dynamics and spatial differences in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Oswald, Sascha; Baroni, Gabriele; Biro, Peter; Schrön, Martin

    2015-04-01

    A novel method to observe changes in soil moisture and other water pools at the land surface is non-invasive cosmic-ray neutron sensing. This approach by its physical principles is placed between in-soil measurements and remote sensing, and retrieves values for an intermediate spatial scale of several hectars, which can be used to quantify stored water at the land surface. It detects variations in the background of neutrons, induced initially from cosmic-rays hitting the atmosphere, and this can be related to interesting quantities at the land surface, such as soil moisture, but to some degree also snow water equivalent and changes in the biomass of vegetation. In a small catchment being used as a long-term landscape observatory of the TERENO initiative we retrieved cosmic-ray neutron measurements for several years, for up to four adjacent sites. The terrain was hilly with some slopes being partly used for agricultural fields, partly grassland. Here, after atmospheric corrections and a calibration procedure soil moisture dynamics could be observed for integral soil depths of several decimeters, clearly responding to precipitation events and offering a comparison to various local and non-local soil moisture measurements there. For winter periods with frost and snow, also the water mass stored in the snow cover can be retrieved. Furthermore, observed spatial differences can be related to vegetation, terrain and soil moisture state. Also, the relation to parameters representing crop biomass and growth will be discussed in respect to the retrieved cosmic-ray neutron signals, which have an influence on the interpretation as soil moisture.

  2. Impacts of intensive agricultural irrigation and livestock farming on a semi-arid Mediterranean catchment.

    PubMed

    Martín-Queller, Emi; Moreno-Mateos, David; Pedrocchi, César; Cervantes, Juan; Martínez, Gonzalo

    2010-08-01

    Irrigation return flows (IRF) are a major contributor of non-point source pollution to surface and groundwater. We evaluated the effects of irrigation on stream hydrochemistry in a Mediterranean semi-arid catchment (Flumen River, NE Spain). The Flumen River was separated into two zones based on the intensity of irrigation activities in the watershed. General linear models were used to compare the two zones. Relevant covariables (urban sewage, pig farming, and gypsum deposits in the basin) were quantified with the help of geographic information system techniques, accompanied by ground-truthing. High variability of the water quality parameters and temporal dynamics caused by irrigation were used to distinguish the two river reaches. Urban activity and livestock farming had a significant effect on water chemistry. An increase in the concentration of salts (240-541 microS.cm(-1) more in winter) and nitrate (average concentrations increased from 8.5 to 20.8 mg.l(-1) during irrigation months) was associated with a higher level of IRF. Those river reaches more strongly influenced by urban areas tended to have higher phosphorus (0.19-0.42 mg.l(-1) more in winter) concentrations. These results support earlier research about the significant consequences to water quality of both urban expansion and intensive agricultural production in arid and semi-arid regions. Data also indicate that salinization of soils, subsoils, surface water, and groundwater can be an unwelcome result of the application of pig manure for fertilization (increase in sodium concentration in 77.9 to 138.6 mg.l(-1)). PMID:19585246

  3. The fate of organic carbon in colluvial soils in a subtropical agricultural catchment (Arvorezinha, Brazil)

    NASA Astrophysics Data System (ADS)

    Van de Broek, Marijn; Van Oost, Kristof; Minella, Jean; Govers, Gerard

    2016-04-01

    One of the main reasons as to why soil erosion is considered to be a carbon sink for the atmosphere is that eroded carbon is often redeposited and buried in depositional environments. However, the quantification of the magnitude of this effect is still uncertain because the residence time of soil organic carbon in depositional environments is ill defined. The latter is especially true for tropical and subtropical areas as field data for these climatic zones are largely lacking. This is an important hiatus as ca. 40% of the total global arable land is located in the (sub-)tropics [1]. We collected samples from four depositional and one stable agricultural profile in a small agricultural catchment in Arvorezinha (Brazil) where deforestation started ca. 90 yrs ago. δ13C depth profiles allowed to identify the bottom of the original A-horizon: this is because δ13C values of the buried forest soils are significantly heavier than those of the colluvial deposits. The results show that soil organic carbon contents systematically decrease with depth below the actual plough layer. This is due to the fact that a significant fraction of the organic carbon that was originally deposited is removed by mineralization from these soils over decadal time scales. As the time of deforestation is known, age-depth curves could be established. Combining this information with SOC measurements allowed for a first estimate of carbon preservation rates and showed that after 70 years ca. 25% of the deposited organic carbon is released to the atmosphere: results were very consistent across profiles. In temperate environments, the time necessary for this fraction of the deposited carbon to be mineralized is somewhat longer, i.e. 100 years [2]. This suggests that soil organic carbon may be decomposed faster in sub-tropical environments in comparison to temperate environments. This is not unexpected, given the fact that average soil temperatures are higher and soils are, in this climate

  4. Influence of Antecedent Hydrologic Conditions on Nitrate and Phosphorus Export from a Small Agricultural Catchment in Southern Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; English, M. C.; Schiff, S. L.; Stone, M.

    2009-04-01

    The ability of the scientific community to quantify and predict discharge and nutrient transport in a range of settings is confounded by the effects of antecedent hydrologic conditions in upland areas. Previous work has empirically linked spatial variables such as land use, soil type, topography, and drainage characteristics to hydrochemical export from various landscapes (e.g. MCDOWELL et al., 2001; ARHEIMER and LIDEN, 2000; STAMM et al., 1998; JORDAN et al., 1997; WELSCH et al., 2001). However, the specific reasons why similar types of events produce different nutrient export patterns are poorly understood. Nutrient (nitrate, soluble and total phosphorus) transport from agricultural catchments is difficult to quantify and predict because of the influence of variable hydrologic flowpaths and their interaction with varying nutrient pools. This research examines the role of antecedent hydrologic conditions on stream discharge and nitrate (NO3-), soluble reactive phosphorus (SRP) and total phosphorus (TP) export from a small (2.7 km2) first-order agricultural catchment in Southern Ontario, Canada. During 59 events occurring over a two-year sampling period (year-round), runoff ratios ranged from 0-0.99). Runoff ratios increased throughout successive events as conditions became wetter although key indices of antecedent wetness such as water table position, pre-event streamflow and soil moisture did not yield predictive relationships. Nitrate, SRP and TP transport from the catchment increased with antecedent wetness during some periods but decreased with antecedent wetness during other periods. This variability appears to be linked to a combination of the position of water table before and during the event, as well as timing of fertilizer application. It is hypothesized that in general, wetter antecedent hydrologic conditions increase nutrient transport from the catchment by increasing macropore connectivity between surface soil horizons and tile drains, although this

  5. Transport of suspended sediment and organic carbon during storm events in a large agricultural catchment, southwest France.

    NASA Astrophysics Data System (ADS)

    Chantha, Oeurng; Sabine, Sauvage; David, Baqué; Alexandra, Coynel; Eric, Maneux; Henri, Etcheber; José-Miguel, Sánchez-Pérez

    2010-05-01

    Intensive agriculture has led to environmental degradation through soil erosion and carbon loss transferred from agricultural land to the stream networks. Suspended sediment transport from the agricultural catchment to the watercourses is responsible for aquatic habitat degradation, reservoir sedimentation, and for transporting sediment associated pollutants (pesticides, nutrient, heavy metals and other toxic substances). Consequently, the temporal transport of suspended sediment (SS), dissolved and particulate organic carbon (DOC and POC) was investigated during 18 months from January 2008 to June 2009 within a large agricultural catchment in southwest France. This study is based on an extensive dataset with high temporal resolution using manual and automatic sampling, especially during 15 flood events. Two main objectives aim at: (i) studying temporal transport in suspended sediment (SS), DOC and POC with factors explaining their dynamics and (ii) analysing the relationships between discharge, SSC, DOC and POC during flood events. The study demonstrates there is a strong variability of SS, POC and DOC during flood events. The SS transport during different seasonal floods varied by event from 513 to 41 750 t; POC transport varied from 12 to 748 t and DOC transport varied from 9 to 218 t. The specific yield of the catchment represents 76 t km-2 y-1 of sediment, 1.8 t km-2 y-1 of POC and 0.7 t km-2 y-1 of DOC, respectively. The POC associated with sediment transport from the catchment accounted for ~2.5% of the total sediment load. Flood duration and flood magnitude are key factors in determining the sediment and organic carbon transport. Statistical analyses revealed strong correlations between total precipitation, flood discharge, total water yield with suspended sediment and organic transport. The relationships of SSC, POC and DOC versus discharge over temporal flood events resulted in different hysteresis patterns which were used to suggest those dissolved and

  6. IDENTIFICATION OF PREDOMINANT ENVIRONMENTAL FACTORS STRUCTURING STREAM MACROINVERTEBRATE COMMUNITIES WITHIN A LARGE AGRICULTURAL CATCHMENT

    EPA Science Inventory

    Patterns of macroinvertebrate community composition were examined in streams within a 40,000-km2 catchment in central Michigan, USA, to identify the major environmental gradients influencing community variation. griculture and associated clay and sandy soils predominated in much ...

  7. Comparing hydrological signatures of small agricultural catchments using uncertain data provided by a soft hydrological monitoring

    NASA Astrophysics Data System (ADS)

    Crabit, Armand; Colin, François

    2016-04-01

    Discharge estimation is one of the greatest challenge for every hydrologist as it is the most classical hydrological variable used in hydrological studies. The key lies in the rating curves and the way they were built: based on field measurements or using physical equations as the Manning-Strickler relation… However, as we all know, data and associated uncertainty deeply impact the veracity of such rating curves that could have serious consequences on data interpretation. And, of all things, this affects every catchment in the world, not only the gauged catchments but also and especially the poorly gauged ones that account for the larger part of the catchment of the world. This study investigates how to compare hydrological behaviour of 11 small (0.1 to 0.6 km2) poorly gauged catchments considering uncertainty associated to their rating curves. It shows how important the uncertainty can be using Manning equation and focus on its parameter: the roughness coefficient. Innovative work has been performed under controlled experimental conditions to estimate the Manning coefficient values for the different cover types observed in studied streams: non-aquatic vegetations. The results show that estimated flow rates using suitable roughness coefficients highly differ from those we should have obtained if we only considered the common values given in the literature. Moreover, it highlights how it could also affect all derived hydrological indicators commonly used to compare hydrological behaviour. Data of rainfall and water depth at a catchment's outlet were recorded using automatic logging equipment during 2008-2009. The hydrological regime is intermittent and the annual precipitation ranged between 569 and 727 mm. Discharge was then estimated using Manning's equation and channel cross-section measurements. Even if discharge uncertainty is high, the results show significant variability between catchment's responses that allows for catchment classification. It also

  8. How Programme Teams Progress Agricultural Innovation in the Australian Dairy Industry

    ERIC Educational Resources Information Center

    Nettle, Ruth; Brightling, Pauline; Hope, Anne

    2013-01-01

    Purpose: This article outlines the emergence of programme teams in the Australian dairy farm sector as a response to counter weaknesses in the institutional environment for agricultural innovation which favours technology adoption/diffusion approaches. Design/methodology/approach: The strengths, weaknesses and risks of different approaches to…

  9. Impact of agricultural practices on runoff and glyphosate peaks in a small vineyard catchment

    NASA Astrophysics Data System (ADS)

    Amiot, Audrey; La Jeunesse, Isabelle; Jadas-Hécart, Alain; Landry, David; Sourice, Stéphane; Communal, Pierre-Yves; Ballouche, Aziz

    2013-04-01

    The Layon River, a tributary of the Loire River, does frequently not comply with water quality standards because of pesticides. Vineyard is generally denounced. The aim of this project is to explain the transfer of pesticides during runoff events and its interaction with erosion. Pesticides and suspended particulate matter (SPM) concentrations are monitored at the outlet of the vineyards catchment each 2 minutes during floods to follow peaks. The results of three different hydrological years (2009, 2011, 2012) are exposed. The 2.2ha catchment is composed of two main vineyards plots managed by two independent farmers. Mean slopes are of 8% and can reach 40% in terraces. A gauging station has been installed at the end of the slope with a calibrated Venturi channel. The measurement station is composed of (a) an approach channel of 10 meters long for the establishment of a stable water surface, (b) a trapezoidal long-throated flume to assess the flow rate with the water level measured with (c) a bubbler sensor, (d) an automatic rain gauge, (e) an automatic sampler, (f) a modem and (g) a logosens OTT® data logger. 2009 was an average year, 2011 was particularly dry and 2012 particularly wet. Quantities of glyphosate applied were respectively 1087, 645 and 720g. Maximum discharges in the gauging station were 5, 12 and 25L.s-1. Minimum and maximum concentrations of glyphosate in runoff waters were 1-449.1 µg.L-1 in 2009, 0.62-13.6 µg.L-1 in 2011 and 0.1-3.7 µg.L-1 in 2012. Minimum and maximum concentrations of SPM were 14-1261mg.L-1 in 2009, 108- 6454 mg.L-1 in 2011 and 9-1541 mg.L-1 in 2012. While flows, quantities of glyphosate applied and peaks of concentrations observed in 2011 are more important in 2009, SPM generated in the runoff waters are lower than 2011 and 2012, even though 2012 has particularly been a wet year. Also, maximum runoff coefficients are 7% in 2009 and 2011 and 57% in 2012. In fact, this latest explains differences between years better than

  10. Investigating suspended sediment dynamics in contrasting agricultural catchments using ex situ turbidity-based suspended sediment monitoring

    NASA Astrophysics Data System (ADS)

    Sherriff, S. C.; Rowan, J. S.; Melland, A. R.; Jordan, P.; Fenton, O.; hUallachain, D. O.

    2015-08-01

    Soil erosion and suspended sediment (SS) pose risks to chemical and ecological water quality. Agricultural activities may accelerate erosional fluxes from bare, poached or compacted soils, and enhance connectivity through modified channels and artificial drainage networks. Storm-event fluxes dominate SS transport in agricultural catchments; therefore, high temporal-resolution monitoring approaches are required, but can be expensive and technically challenging. Here, the performance of in situ turbidity sensors, conventionally installed submerged at the river bankside, is compared with installations where river water is delivered to sensors ex situ, i.e. within instrument kiosks on the riverbank, at two experimental catchments (Grassland B and Arable B). The in situ and ex situ installations gave comparable results when calibrated against storm-period, depth-integrated SS data, with total loads at Grassland B estimated at 12 800 and 15 400 t, and 22 600 and 24 900 t at Arable B, respectively. The absence of spurious turbidity readings relating to bankside debris around the in situ sensor and its greater security make the ex situ sensor more robust. The ex situ approach was then used to characterise SS dynamics and fluxes in five intensively managed agricultural catchments in Ireland which feature a range of landscape characteristics and land use pressures. Average annual suspended sediment concentration (SSC) was below the Freshwater Fish Directive (78/659/EEC) guideline of 25 mg L-1, and the continuous hourly record demonstrated that exceedance occurred less than 12 % of the observation year. Soil drainage class and proportion of arable land were key controls determining flux rates, but all catchments reported a high degree of inter-annual variability associated with variable precipitation patterns compared to the long-term average. Poorly drained soils had greater sensitivity to runoff and soil erosion, particularly in catchments with periods of bare soils. Well

  11. Identifying the controls of soil loss in agricultural catchments using ex situ turbidity-based suspended sediment monitoring

    NASA Astrophysics Data System (ADS)

    Sherriff, S. C.; Rowan, J. S.; Melland, A. R.; Jordan, P.; Fenton, O.; Ó'hUallacháin, D.

    2015-03-01

    Soil erosion and suspended sediment (SS) pose risks to chemical and ecological water quality. Agricultural activities may accelerate erosional fluxes from bare, poached or compacted soils, and enhance connectivity through modified channels and artificial drainage networks. Storm-event fluxes dominate SS transport in agricultural catchments; therefore, high temporal-resolution monitoring approaches are required but can be expensive and technically challenging. Here, the performance of in situ turbidity-sensors, conventionally installed submerged at the river bankside, is compared with installations where river water is delivered to sensors ex situ, i.e. within instrument kiosks on the riverbank, at two experimental catchments (Grassland B and Arable B). Calibrated against storm-period depth-integrated SS data, both systems gave comparable results; using the ex situ and in situ methods respectively, total load at Grassland B was estimated at 128 ± 28 and 154 ± 35, and 225 ± 54 and 248 ± 52 t at Arable B. The absence of spurious turbidity peaks relating to bankside debris around the in situ sensor and its greater security, make the ex situ sensor more robust. The ex situ approach was then used to characterise SS dynamics and fluxes in five intensively managed agricultural catchments in Ireland which feature a range of landscape characteristics and land use pressures. Average annual suspended sediment concentration (SSC) was below the Freshwater Fish Directive (FFD) guideline of 25 mg L-1, and the continuous hourly record demonstrated that exceedance occurred less than 12% of the observation year. Soil drainage class and proportion of arable land were key controls determining flux rates, but all catchments reported a high degree of inter-annual variability associated with variable precipitation patterns compared to the long-term average. Poorly-drained soils had greater sensitivity to runoff and soil erosion, particularly in catchments with periods of bare soils

  12. Assessment of climate change and increased atmospheric CO2 impacts on water quality in an intensive agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Salmon-Monviola, Jordy; Moreau, Pierre; Benhamou, Cyril; Durand, Patrick; Merot, Philippe; Oehler, François; Gascuel-Odoux, Chantal

    2013-04-01

    Climate change and increasing atmospheric CO2 concentration can lead to disturbances in the global hydrological and nitrogen (N) cycling, and losses in catchment systems. Potential impacts on water and N cycling have been studied in large catchments with a variety of land uses but less attention has focused on agricultural headwater catchments. Despite their relatively small dimensions, headwater catchments of 1-10 km² play a dominant role in N transformations in the landscape, and streams in such catchments may have major impacts on downstream water quantity and quality. This issue is particular important for agricultural catchment which have to reach the WFD targets, where land use changes has to be analysed in combination with climate change. The effects of climate change and rising concentrations of atmospheric CO2 have been studied on (1) changes in hydrological and N balance components on a yearly basis and (2) the seasonal dynamics of water and N fluxes. The spatially distributed agro-hydrological model TNT2 (Topography-based nitrogen Transfers and Transformations) driven by ARPEGE (Action de Recherche Petite Echelle Grande Echelle) climate-model outputs from A1B scenario have been applied on the Kervidy-Naizin headwater catchment (western France), a long term hydrological observatory. Consideration of atmospheric CO2 concentration was implemented at two levels in TNT2: i) to account for the CO2 effect on stomatal conductance TNT2; ii) to consider effect of CO2 on biomass growth. Climate data from ARPEGE model, corrected with the quantile-quantile bias correction method, over 30-year simulation periods were used as TNT2 input (Salmon-Monviola et al., in review). With increased CO2, the main trends in water balance were a significant decrease in annual actual evapotranspiration, a moderate decrease in annual discharge and wetland extent, and a decrease in spring and summer of groundwater recharge and soil water content. Not considering the effects of

  13. Implications of climate change scenarios for agriculture in alpine regions--a case study in the Swiss Rhone catchment.

    PubMed

    Fuhrer, J; Smith, P; Gobiet, A

    2014-09-15

    Coping with climate change in agriculture requires knowledge of trends in agro-climatic conditions with a focus at the smaller scales where decisions are taken. As part of the EU FP7 ACQWA project, the situation was analyzed for agriculture in the case of the Swiss Rhone catchment (Valais) where cultivation of permanent crops (orchards and vineyards) and livestock production are the most important agro-economic activities. The aim of this study was to use daily data from four downscaled and bias corrected transient climate change scenarios to analyze changes in water and temperature related indices over the period 1951-2050 for three locations (Aigle, Sion, Montana) that are representative of different production zones in the catchment. The results indicate that most relevant implications are caused by projected changes in temperature and not in precipitation. They indicate an extension of the thermal growing season with potentially positive effects on pasture and livestock production, most pronounced at the mountain site (Montana), but a trend towards increasing risks of frost in permanent crops and in heat stress for livestock at the valley bottom (Aigle, Sion). The increase in water requirement for irrigation in 2021-2050 relative to 1981-2009 is moderate (4-16%, depending on location). However, in years with low amounts of snow and rain, in small catchments with a nival regime, reduced water supply by rivers could restrict the surface area of grassland that can be irrigated, particularly during springtime. It is concluded that coping with heat-related risks may be most needed at the lower cropland and pasture sites while water-related issues would become more relevant in more elevated locations where pasture-based livestock production is the dominant type of agricultural land use. PMID:23830922

  14. Assessment of hydrology, suspended sediment and particulate organic carbon transport in a large agricultural catchment using SWAT model

    NASA Astrophysics Data System (ADS)

    Chantha, Oeurng; Sabine, Sauvage; José-Miguel, Sánchez-Pérez

    2010-05-01

    Suspended sediment transport from agricultural catchments to stream networks is responsible for aquatic habitat degradation, reservoir sedimentation and the transport of sediment-bound pollutants (pesticides, particulate nutrients, heavy metals and other toxic substances). Quantifying and understanding the dynamics of suspended sediment transfer from agricultural land to watercourses is essential in controlling soil erosion and in implementing appropriate mitigation practices to reduce stream suspended sediment and associated pollutant loads, and hence improve surface water quality downstream. Gascogne area, southwest France, has been dominated by anthropogenic activities particularly intensive agriculture causing severe erosion in recent decades. This leads to a major threat to surface water quality due to soil erosion. Therefore, the catchment water quality has been continuously monitored since January 2007 and the historical data of hydrology and suspended sediment has existed since 1998. In this study, the Soil and Water Assessment Tool (SWAT 2005) was applied to assess hydrology, suspended sediment and particulate organic carbon in this catchment Agricultural management practices (crop rotation, planting date, fertilizer quantity and irrigations) were taken into the model for simulation period of 11 years (July, 1998 to March, 2009). The investigation was conducted using a 11-year streamflow and two years of suspended sediment record from January 2007 to March 2009. Modelling strategy with dominant landuse and soil type was chosen in this study. The SWAT generally performs satisfactorily and could simulate both daily and monthly runoff and sediment yield. The simulated daily and monthly runoff matched the observed values satisfactorily (ENash>0.5). For suspended sediment simulation, the simulated values were compared with the observed continuous suspended sediment derived from turbidity data. Based on the relationship between SSC and POC (R2 = 0.93), POC was

  15. Application of strontium isotope measurements to trace sediment sources in an upstream agricultural catchment (Loire River basin, France)

    NASA Astrophysics Data System (ADS)

    Le Gall, Marion; Evrard, Olivier; Thil, François; Foucher, Anthony; Salvador-Blanes, Sébastien; Cerdan, Olivier; Ayrault, Sophie

    2015-04-01

    Soil erosion is recognized as one of the main processes of land degradation in agricultural areas. It accelerates the supply of sediment to the rivers and degrades water quality. To limit those impacts and optimize management programs in such areas, sources of sediment need to be identified and sediment transport to be controlled. Here, we determined the sources of suspended sediment in the Louroux (24 km², French Loire River basin), a small catchment representative of lowland cultivated environments of Northwestern Europe. In this catchment, channels have been reshaped and 220 tile drain outlets have been installed over the last several decades. As a result, soil erosion and sediment fluxes have increased drastically. The variation of 87Sr/86Sr ratios, driven by the weathering of rocks with different ages and chemical composition, may reflect the mixing of different sediment sources. Strontium isotopic ratios (87Sr/86Sr) were therefore determined in potential soil sources, suspended particulate matter (SPM) and a sediment core sampled in the Louroux Pond at the catchment outlet. Soil, SPM and core samples displayed significantly different isotopic signatures. 87Sr/86Sr ratios in soil samples varied from 0.712763 to 0.724631 ± 0.000017 (2σ, n=20). Highest values were observed in silicic parts of the catchment whereas the lower values were identified in a calcareous area close to the Louroux Pond. 87Sr/86Sr ratios in SPM (0.713660 to 0.725749 ± 0.000017, 2σ, n=20) plotted between the soil and sediment core (0.712255 to 0.716415 ± 0.000017, 2σ, n=12), suggesting the presence of particles originating from at least two different lithological sources, i.e. silicic rocks and carbonate material. Variations in 87Sr/86Sr ratios in the outlet core sample were used to reconstruct the sedimentary dynamics in the catchment during the last decades. These results will guide the future implementation of appropriate management practices aiming to reduce erosion in upstream

  16. The 20th century whole-basin trophic history of an inter-drumlin lake in an agricultural catchment.

    PubMed

    Jordan, Philip; Rippey, Brian; Anderson, N John

    2002-10-01

    Eight 1-m sediment cores were extracted from across the basin of Friary Lough, a 5.4-ha eutrophic lake in a wholly grassland agricultural catchment in Co. Tyrone, Northern Ireland. Sedimentary TP, diatom inferred TP, Ca, Na, Fe, Mn, loss-on-ignition (LOI), dry weight and density were determined in the core profiles. Core dating and correlation gave a 210Pb, 137Cs and 241Am chronology from 1906 to 1995 and enabled a whole-basin estimate of chemical and sediment accumulation rate over the 20th Century. The major changes for all parameters occurred after c. 1946. Sediment accumulation rate was most influenced by organic matter accumulations, probably of planktonic origin, and increasing after c. 1946. Inorganic sediment accumulation rate was found to be largely unchanging through the century at 10 t km(-2) yr(-1) when expressed as catchment exports. All chemical accumulation rate changes occurred after c. 1946. Total phosphorus accumulation rate, however, was found to be the only chemical to be increasing throughout the epilimnion and hypolimnion areas of the sedimentary basin at an average of 22.5 mg m(-2) yr(-1) between 1946 and 1995. The other chemical parameters showed increasing accumulation rates after c. 1946 in the epilimnion part of the basin only. Interpreted in terms of whole-basin sedimentation and catchment export processes over time, it is suggested that diffuse TP inputs are independent of sediment inputs. This corresponds to hydrochemical models that suggest soluble P as the primary fraction that is lost from grassland catchments. The increase in sedimentary TP accumulation rate, and DI-TP concentration, are also explained with regard to current models that suggest increases in runoff P concentrations from elevated soil P concentrations. Increases in eplimnion chemical and sediment accumulation rate after c. 1946 may be due to local erosion that has limited impact on lake basin sedimentation. PMID:12389788

  17. Using the Provenance of Sediment and Bioavailable Phosphorus to Help Mitigate Water Quality Impact in an Agricultural Catchment.

    PubMed

    McDowell, R W; Norris, M; Cox, N

    2016-07-01

    The quality and health of surface waters can be impaired by sediment and sediment-bound phosphorus (P). The Waituna Lagoon catchment in southern New Zealand has undergone agricultural intensification that has been linked to increases in sediment and sediment-bound bioavailable P (BAP) in the lagoon. Time-integrated samplers trapped suspended sediment from the water column, and their geochemical signature was compared with likely sources (stream banks, stream beds, topsoil, and subsoil) in each of the lagoon's contributing streams and rivers. The proportion of BAP, but not necessarily total P, within trapped sediment was much greater in samples from the Moffat and Carran Creeks than from the Waituna Creek, probably due to the erosion of organic-rich soils that had little capacity to retain P compared with the more mineral soils of the Waituna Creek. Annually, most BAP and sediment came from bank erosion, and strategies such as fencing out stock should focus on minimizing this throughout the catchment. However, when considering losses in space and time relative to the impact on the Waituna Lagoon, strategies the Waituna Creek catchment should also minimize contributions from topsoil in winter-spring, whereas in the Carran and Moffat Creek catchments strategies need to decrease P inputs (e.g., effluent) to Organic soils likely to lose much BAP in summer-autumn when the impact on the Lagoon is quickest. This study highlighted the need to identify sources and timings of BAP and sediment loss before recommending mitigation practices, which without this information may be slow or not succeed. PMID:27380076

  18. Runoff production in a small agricultural catchment in Lao PDR: influence of slope, land-use and observation scale

    NASA Astrophysics Data System (ADS)

    Patin, J.; Ribolzi, O.; Mugler, C.; Valentin, C.; Mouche, E.

    2010-12-01

    After years of traditional slash and burn cultures, the Houay Pano catchment is now under high land pressures due to population resettling and environmental preservation policies. This evolution leads to rapid land-use changes in the uplands, such as fallow time reductions and growing of cash crops as teaks or banana. The catchment is located in the Luang Prabang province, in the north of Lao PDR and was selected in late 1998 as a benchmark site for the Managing Soil Erosion Consortium (MSEC). It is a small (60ha) agricultural catchment representative of the rural mountainous South East Asia : it exhibits steep cultivated slopes (from 2% to more than 110%) under a wet-dry monsoon climate. To understand the partition between runoff and infiltration, data from runoff on 20 plot experiments (1m2) under natural rainfall and with representative slopes and land uses is collected from 2003 to 2009. A simulated rainfall experiment was conducted in 2002 on bare soil plots (1m2) with different antecedent cultures. We investigate the role of crust, slope and land-use on runoff production at different scales. A model accounting for small scale variability is applied to compute the time and space variations of soil infiltrability at the plot scale (1m2) and sub-catchment scale (0.6ha). From the hypothesis of exponentially distributed infiltrabilities at the centimeter scale, we found that infiltration is log-normaly distributed over time for a given land use. The median infiltrability vary from 10mm/h under teak cultures to 150mm/h on plots with fallow. Variations along a year are tribute to many meteorological and human factors.

  19. Scale appropriate modelling to represent dominant pollution processes in agricultural catchments, to underpin management and policy decisions

    NASA Astrophysics Data System (ADS)

    Adams, Russell; Quinn, Paul

    2014-05-01

    We present the development of scale appropriate modelling techniques to represent dominant pollution processes in agricultural catchments to underpin catchment management and its implications on policy. A quasi-physically based, spatially lumped macro-model (CRAFT), has been developed to assess mitigation options for nitrogen and phosphorus. CRAFT has been developed to use daily time series data of rainfall, stream flow and nutrient concentration data, and can be applied to catchments varying in size from a few hectares to 100s of square kilometres. If stream flow routing is added to the model then potentially larger catchments and sub-daily time steps could be represented. There are two key issues addressed here. Firstly, the model can be used to assess the usefulness of monitoring data collected at a high temporal resolution at considerable expense compared to routine grab sampling. An earlier study in the Frome catchment in southern England collected sub-daily water quality data for more than 12 months at the catchment outlet, comprising: total oxidised nitrogen (TON); soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations. The three data sets have quite different temporal signals relating to flow pathways with different residence times and the importance of runoff events in generating acute pollution. The flexible model structure was therefore developed to include different sources of runoff including overland flow from impervious areas in the catchment, where pollution hotspots will be located (e.g. farmyards). The model has been used to assess the value of collecting high resolution monitoring data, in this case by resampling the Frome sub-daily data to a daily timestep, and comparing these model simulations against those calibrated using all the samples. The usefulness of the high resolution data can be assessed on whether a daily model would undepredict (for example) high nutrient concentrations that can be identified in the sub

  20. SUSTAINABLE AGRICULTURE FOR THE WATER CATCHMENT PROTECTION AREA IN NTISAW, CAMEROON

    EPA Science Inventory

    We expect that the catchment area will increase food output for the community in addition to preserving the water source. Increased food output will benefit needy residents and allow them to focus more on education and economic development. Additionally, an area of sustainable...

  1. Spatial heterogeneity of mobilization processes and input pathways of herbicides into a brook in a small agricultural catchment

    NASA Astrophysics Data System (ADS)

    Doppler, Tobias; Lück, Alfred; Popow, Gabriel; Strahm, Ivo; Winiger, Luca; Gaj, Marcel; Singer, Heinz; Stamm, Christian

    2010-05-01

    Soil applied herbicides can be transported from their point of application (agricultural field) to surface waters during rain events. There they can have harmful effects on aquatic species. Since the spatial distribution of mobilization and transport processes is very heterogeneous, the contributions of different fields to the total load in a surface water body may differ considerably. The localization of especially critical areas (contributing areas) can help to efficiently minimize herbicide inputs to surface waters. An agricultural field becomes a contributing area when three conditions are met: 1) herbicides are applied, 2) herbicides are mobilized on the field and 3) the mobilized herbicides are transported rapidly to the surface water. In spring 2009, a controlled herbicide application was performed on corn fields in a small (ca 1 km2) catchment with intensive crop production in the Swiss plateau. Subsequently water samples were taken at different locations in the catchment with a high temporal resolution during rain events. We observed both saturation excess and hortonian overland flow during the field campaign. Both can be important mobilization processes depending on the intensity and quantity of the rain. This can lead to different contributing areas during different types of rain events. We will show data on the spatial distribution of herbicide loads during different types of rain events. Also the connectivity of the fields with the brook is spatially heterogeneous. Most of the fields are disconnected from the brook by internal sinks in the catchment, which prevents surface runoff from entering the brook directly. Surface runoff from these disconnected areas can only enter the brook rapidly via macropore-flow into tile drains beneath the internal sinks or via direct shortcuts to the drainage system (maintenance manholes, farmyard or road drains). We will show spatially distributed data on herbicide concentration in purely subsurface systems which shows

  2. Flood survey of nitrate behaviour using nitrogen isotope tracing in the critical zone of a French agricultural catchment

    NASA Astrophysics Data System (ADS)

    Paul, Alexia; Moussa, Issam; Payre, Virginie; Probst, Anne; Probst, Jean-Luc

    2015-11-01

    Measurements of δ15N-NO3- were taken in a highly flood-responsive agricultural catchment in the southwest of France to trace the sources and transfer pathways of nitrates during flood events. From January to March 2013, surface water samples were collected every week at the outlet, and four floods were sampled with a high resolution. Sampling was also performed in surface waters and sand lenses from the rest of the basin to trace nitrate sources and processes spatially. Nitrate extractions were performed using a method based on the solubility difference between inorganic salts and organic solutions. The δ15N values were in the range of surface water contaminated by N-fertilisers. Depending on the hydroclimatic event, nitrates resulted from a combination of sources and processes. At the start of the floods, the values of δ15N-NO3- and nitrate concentrations were low, demonstrating the dilution of water with rainwater. During a second phase, the nitrate concentration and the δ15N were higher. Deeper waters and soil solutions were the second source of nitrates. When the water level was low, both nitrate concentration and isotopic composition were high. These values reflected the denitrification processes that occurred in the soil under anaerobic conditions. An analysis of δ15N-NO3- in stream water in a small agricultural catchment was efficient at determining the origin of nitrates during flood events using a simple method.

  3. Runoff and sediment loss responses to rainfall and land use in two agricultural catchments on the Loess Plateau of China

    NASA Astrophysics Data System (ADS)

    Kang, Shaozhong; Zhang, Lu; Song, Xiaoyu; Zhang, Shuhan; Liu, Xianzhao; Liang, Yinli; Zheng, Shiqing

    2001-04-01

    Soil erosion is a severe problem hindering sustainable agriculture on the Loess Plateau of China. Plot experiments were conducted under the natural rainfall condition during 1995-1997 at Wangdongguo and Aobao catchments in this region to evaluate the effects of various land use, cropping systems, land slopes and rainfall on runoff and sediment losses, as well as the differences in catchment responses. The experiments included various surface conditions ranging from bare soil to vegetated surfaces (maize, wheat residue, Robinia pseudoacacia L., Amorpha fruticosa L., Stipa capillata L., buckwheat and Astragarus adsurgens L.). The measurements were carried out on hill slopes with different gradients (i.e. 0 ° to 36 °). These plots varied from 20 to 60 m in length. Results indicated that runoff and erosion in this region occurred mainly during summer storms. Summer runoff and sediment losses under cropping and other vegetation were significantly less than those from ploughed bare soil (i.e. without crop/plant or crop residue). There were fewer runoff and sediment losses with increasing canopy cover. Land slope had a major effect on runoff and sediment losses and this effect was markedly larger in the tillage plots than that in the natural grass and forest plots, although this effect was very small when the maximum rainfall intensity was larger than 58·8 mm/h or smaller than 2·4 mm/h. Sediment losses per unit area rose with increasing slope length for the same land slope and same land use. The effect of slope length on sediment losses was stronger on a bare soil plot than on a crop/plant plot. The runoff volume and sediment losses were both closely related to rainfall volume and maximum intensity, while runoff coefficient was mainly controlled by maximum rainfall intensity. Hortonian overland flow is the dominant runoff process in the region. The differences in runoff volume, runoff coefficient and sediment losses between the catchments are mainly controlled by the

  4. Impact of conservation agriculture on catchment runoff and soil loss under changing climate conditions in May Zeg-zeg (Ethiopia)

    NASA Astrophysics Data System (ADS)

    Lanckriet, Sil; Araya, Tesfay; Cornelis, Wim; Verfaillie, Els; Poesen, Jean; Govaerts, Bram; Bauer, Hans; Deckers, Jozef; Haile, Mitiku; Nyssen, Jan

    2012-12-01

    SummaryThis study evaluates the practice of conservation agriculture (CA) in the May Zeg-zeg catchment (MZZ; 187 ha) in the North Ethiopian Highlands as a soil management technique for reducing soil loss and runoff, and assesses the consequences of future large-scale implementation on soil and hydrology at catchment-level. The study of such practice is important especially under conditions of climate change, since EdGCM (Educational Global Climate Model) simulation predicts by 2040 an increase in precipitation by more than 100 mm yr-1 in the study area. Firstly, field-saturated infiltration rates, together with soil texture and soil organic carbon contents, were measured. The relation with local topography allows to generate a pedotransfer function for field-saturated infiltration rate, and spatial interpolation with Linear Regression Mapping was used to map field-saturated infiltration rates optimally within the catchment. Secondly, on several farmlands, CA was checked against plain tillage (PT) for values of field-saturated infiltration rates, soil organic carbon, runoff and soil loss. Results show no significant differences for infiltration rates but significant differences for runoff and soil loss (as measured in the period 2005-2011). Runoff coefficients were 30.4% for PT and 18.8% for CA; soil losses were 35.4 t ha-1 yr-1 for PT and 14.4 t ha-1 yr-1 for CA. Thirdly, all collected information was used to predict future catchment hydrological response for full-implementation of CA under the predicted wetter climate (simulation with EdGCM). Curve Numbers for farmlands with CA were calculated. An area-weighted Curve Number allows the simulation of the 2011 rainy season runoff, predicting a total runoff depth of 23.5 mm under CA and 27.9 mm under PT. Furthermore, the Revised Universal Soil Loss Equation management factor P was calibrated for CA. Results also show the important influence of increased surface roughness on water ponding, modeled with a hydrologic

  5. Spatio-temporal variability of shallow groundwater quality in a typical agricultural catchment in subtropical central China

    NASA Astrophysics Data System (ADS)

    Liu, X.

    2015-12-01

    Excessive agriculture-sourced N leaching into shallow groundwater has deteriorated the domestic water quality in rural China. To effectively prevent the above environmental contamination issue, it is an essential prerequisite of exploring the spatio-temporal variability (stV) of the groundwater quality. In this study, a large observation program was deployed to observe ammonium-N (NH4N), nitrate-N (NO3N) and total N (TN) concentrations in 194 groundwater observation wells (1.5 m deep from soil surface) from April 2010 to November 2012 in the Jinjing river catchment in Hunan Province of China. A logit function was applied to transform NH4N, NO3N and TN data for normality; the resultant variables were thus named as NH4Nt, NO3Nt and TNt, respectively. A spatio-temporal semivariogram model in a sum-metric form was used to quantify the stV of NH4Nt, NO3Nt and TNt. The results indicated that the 33-month means ± standard deviations of the NH4N, NO3N and TN concentrations were 0.75±0.10, 1.60±0.19 and 2.99±0.29 mg N L-1, respectively. NH4Nt and NO3Nt exhibited a strong spatio-temporal dependence, while TNt only presented a strong temporal structure. Spatio-temporal ordinary kriging (stOK) was applied to predict the spatio-temporal distributions of NH4N, NO3N and TN over the catchment. The cross-validation results indicated that the stOK predictions for NH4N (r=0.48, RMSE=1.11 mg N L-1), NO3N (r=0.46, RMSE=1.21 mg N L-1) outperformed that for TN (r=0.29, RMSE=2.11 mg N L-1). Referenced to the Chinese Environmental Quality Standards for Groundwater (GB/T 14848-93), the proportions of areas contaminated by NH4N, NO3N and TN in the catchment over a 33-month period were 20.5%, 1.46%, and 5.07%, respectively. Our findings suggested that the Jinjing groundwater was mainly polluted by NH4N, which is probably attributed to the intensive rice agriculture featured with high urea fertilizer applications in the catchment.

  6. Downstream mixing of sediment and tracers in agricultural catchments: Evidence of changing sediment sources and fluvial processes?

    NASA Astrophysics Data System (ADS)

    Ralph, Timothy; Wethered, Adam; Smith, Hugh; Heijnis, Henk

    2014-05-01

    Land clearance, soil tillage and grazing in agricultural catchments have liberated sediment and altered hydrological connectivity between hillslopes and channels, leading to increased sediment availability, mobilisation and delivery to rivers. The type and amount of sediment supplied to rivers is critical for fluvial geomorphology and aquatic ecosystem health. Contemporary sediment dynamics are routinely investigated using environmental radionuclides such as caesium-137 (Cs-137) and excess lead-210 (Pb-210ex), which can provide information regarding sediment source types and fluvial processes if sediment sources can be distinguished from one another and mixing models applied to representative samples. However, downstream transport, mixing and dilution of radionuclide-labelled sediment (especially from sources with low initial concentrations) can obliterate the tracer signal; sometimes before anything of geomorphological importance happens in the catchment. Can these findings be used as evidence of sediment source variations and fluvial processes when the limits of detection (of Cs-137 in particular) are being exceeded so rapidly downstream? Sediment sources and downstream sediment dynamics were investigated in Coolbaggie Creek, a major supplier of sediment to the Macquarie River in an agricultural catchment with temperate to semi-arid climate in Australia. Radionuclides were used to discriminate between the <63 micron fraction of sediment sources including forested topsoils (Cs-137 11.28 +/- 0.75 Bq/kg; Pb-210ex 181.87 +/- 20.00 Bq/kg), agricultural topsoils (Cs-137 3.21 +/- 0.26 Bq/kg; Pb-210ex 29.59 +/- 10.94 Bq/kg) and sub-soils from channel banks and gullies (Cs-137 1.45 +/- 0.47 Bq/kg; Pb-210ex 4.67 +/- 1.93 Bq/kg). Within the trunk stream, suspended sediment, organic matter and Cs-137 and Pb-210ex concentrations declined downstream. Results from a mixing model suggest that agricultural topsoils account for 95% of fine sediment entering the channel in the

  7. An integrated model for simulating nitrogen trading in an agricultural catchment with complex hydrogeology.

    PubMed

    Cox, T J; Rutherford, J C; Kerr, S C; Smeaton, D C; Palliser, C C

    2013-09-30

    Nitrogen loads to several New Zealand lakes are dominated by nonpoint runoff from pastoral farmland which adversely affects lake water quality. A 'cap and trade' scheme is being considered to help meet targets set for nitrogen loads to Lake Rotorua, and a numerical model, NTRADER, has been developed to simulate and compare alternative schemes. NTRADER models both the geophysics of nitrogen generation and transport, including groundwater lag times, and the economics of 'cap and trade' schemes. It integrates the output from several existing models, including a farm-scale nitrogen leaching and abatement model, a farm-scale management economic model, and a catchment-scale nitrogen transport model. This paper details modeling methods and compares possible trading program design features for the Lake Rotorua catchment. Model simulations demonstrate how a cap and trade program could be used to effectively achieve challenging environmental goals in the targeted catchment. However, results also show that, due to complex hydrogeology, satisfactory environmental outcomes may be not achieved unless groundwater lag times are incorporated into the regulatory scheme. One way to do this, as demonstrated here, would be to explicitly include lag times in the cap and trade program. The utility of the model is further demonstrated by quantifying relative differences in abatement costs across potential regulatory schemes. PMID:23771202

  8. Climate Change Impact on the Hydrology and Water Quality of a Small Partially-Irrigated Agricultural Lowland Catchment

    NASA Astrophysics Data System (ADS)

    Visser, A.; Kroes, J.; van Vliet, M. T.; Blenkinsop, S.; Broers, H.

    2010-12-01

    The objective of this study was to assess the potential effects of climate change on the hydrology of the small partially-irrigated agricultural lowland catchment of the Keersop, in south of the Netherlands, as well as the transport of a pre-existing spatially extensive trace metal contamination. The area surrounding the Keersop has been contaminated with heavy metals by the atmospheric emissions of four zinc ore smelters. This heavy metal contamination, with Cd and Zn for example, has accumulated in the topsoil and leaches towards the surface water system, especially during periods with high groundwater levels and high discharge rates. Daily time-series of precipitation and potential evapotranspiration were derived from the results of eight regional climate model experiments under the SRES A2 emissions scenario. They each span 100 years and are representative for the periods 1961-1990 (“baseline climate”) and 2071-2100 (“future climate”). The time-series of future climate were characterized by lower precipitation (-1% to -12%) and higher air temperatures (between 2°C and 5°C), and as a result higher potential evapotranspiration, especially in summer. The time-series were used to drive the quasi-2D unsaturated-saturated zone model (SWAP) of the Keersop catchment (43 km2). The model consisted of an ensemble of 686 1D models, each of which represented a 250x250 m area within the catchment. Simulation results for the future climate scenarios show a shift in the water balance of the catchment. The decrease in annual rainfall is nearly compensated by an increase in irrigation in the catchment, if present day irrigation rules are followed. On the other hand, both evaporation and transpiration fluxes increase. This increase is compensated by a decrease in the drainage flux and groundwater recharge. As a result, groundwater levels decline and the annual discharge of the Keersop stream decreases under all future climate scenarios, by 26% to 46%. Because Cd and Zn

  9. Nitrate sinks and sources as controls of spatio-temporal water quality dynamics in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Schuetz, T.; Gascuel-Odoux, C.; Durand, P.; Weiler, M.

    2015-08-01

    Several controls are known to affect water quality of stream networks during flow recession periods such as solute leaching processes, surface water - groundwater interactions as well as biogeochemical in-stream retention processes. Throughout the stream network combinations of specific water and solute export rates and local in-stream conditions overlay the biogeochemical signals from upstream sections. Therefore, upstream sections can be considered as functional units which could be distinguished and ordered regarding their relative contribution to nutrient dynamics at the catchment outlet. Based on synoptic sampling of flow and nitrate concentrations along the stream in an agricultural headwater during the summer flow recession period, we determined spatial and temporal patterns of water quality for the whole stream. A data-driven, in-stream-mixing-and-removal model was developed and applied for analyzing the spatio-temporal in-stream retention processes and their effect on the spatio-temporal fluxes of nitrates from sub-catchments. Thereby, we have been able to distinguish between nitrate sinks and sources per stream reaches and sub-catchments. For nitrate sources we have determined their permanent and temporally impact on stream water quality and for nitrate sinks we have found increasing nitrate removal efficiencies from up- to downstream. Our results highlight the importance of distinct nitrate source locations within the watershed for in-stream concentrations and in-stream removal processes, respectively. Thus, our findings contribute to the development of a more dynamic perception of water quality in streams and rivers concerning ecological and sustainable water resources management.

  10. Opportunities provided by UAVs to monitor erosion processes in agricultural catchments: a case study from Northern France

    NASA Astrophysics Data System (ADS)

    Frankl, Amaury; Stal, Cornelis; De Wit, Bart; De Wulf, Alain; Salvador, Pierre-Gil; Nyssen, Jan

    2014-05-01

    In erosion studies, accurate spatio-temporal data are required to fully understand the processes involved and their relationship with environmental controls. With cameras being mounted on Unmanned Aerial Vehicles (UAVs), the latter allow to collect low-altitude aerial photographs over small catchments in a cost-effective and rapid way. From large data sets of overlapping aerial photographs, Structure from Motion - Multi View Stereo workflows, integrated in various software such as PhotoScan used here, allow to produced detailed Digital Surface Models (DSMs) and ortho-mosaics. In this study we present the results from a survey carried out in a small agricultural catchment near Hallines, in Northern France. A DSM and ortho-mosaic was produced of the catchment using photographs taken from a low-cost radio-controlled microdrone (DroneFlyer Hexacopter). Photographs were taken with a Sony Nex 5 (16.1 M pixels) camera having a fixed normal lens of 50 mm. In the field, Ground Control Points were materialized by unambiguously determinable targets, measured with a 1'' total station (Leica TS15i). Cross-sections of rills and ephemeral gullies were also quantified from total station measurements and from terrestrial image-based 3D modelling. These data allowed to define the accuracy of the DSM and the representation of the erosion features in it. The feasibility of UAVs photographic surveys to improve our understanding on water-erosion processes such as sheet, rill and gully erosion is discussed. Keywords: Ephemeral gully, Erosion study, Image-based 3D modelling, Microdrone, Rill, UAVs.

  11. Impact of selected agricultural management options on the reduction of nitrogen loads in three representative meso scale catchments in Central Germany.

    PubMed

    Rode, Michael; Thiel, Enrico; Franko, Uwe; Wenk, Gerald; Hesser, Fred

    2009-05-15

    Nitrogen inputs into surface waters from diffuse sources are still unduly high and the assessment of mitigation measures is associated with large uncertainties. The objective of this paper is to investigate selected agricultural management scenarios on nitrogen loads and to assess the impact of differing catchment characteristics in central Germany. A new modelling approach, which simulates spatially distributed N-transport and transformation processes in soil and groundwater, was applied to three meso scale catchments with strongly deviating climate, soil and topography conditions. The approach uses the integrated modelling framework JAMS to link an agro-ecosystem, a rainfall-runoff and a groundwater nitrogen transport model. Different agricultural management measures with deviating levels of acceptance were analysed in the three study catchments. N-leaching rates in all three catchments varied with soil type, the lowest leaching rates being obtained for loess soil catchment (18.5 kg nitrate N ha(-1) yr(-1)) and the highest for the sandy soils catchment (41.2 kg nitrate N ha(-1) yr(-1)). The simulated baseflow nitrogen concentrations varied between the catchments from 1 to 6 mg N l(-1), reflecting the nitrogen reduction capacity of the subsurfaces. The management scenarios showed that the highest N leaching reduction could be achieved by good site-adapted agricultural management options. Nitrogen retention in the subsurface did not alter the ranking of the management scenarios calculated as losses from the soil zone. The reduction effect depended strongly on site specific conditions, especially climate, soil variety and the regional formation of the crop rotations. PMID:19261322

  12. Applicability of rapid and on-site measured enzyme activity for surface water quality monitoring in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Stadler, Philipp; Farnleitner, Andreas H.; Sommer, Regina; Kumpan, Monika; Zessner, Matthias

    2014-05-01

    For the near real time and on-site detection of microbiological fecal pollution of water, the measurement of beta-D- Glucuronidase (GLUC) enzymatic activity has been suggested as a surrogate parameter and has been already successfully operated for water quality monitoring of ground water resources (Ryzinska-Paier et al. 2014). Due to possible short measure intervals of three hours, this method has high potential as a water quality monitoring tool. While cultivation based standard determination takes more than one working day (Cabral 2010) the potential advantage of detecting the GLUC activity is the high temporal measuring resolution. Yet, there is still a big gap of knowledge on the fecal indication capacity of GLUC (specificity, sensitivity, persistence, etc.) in relation to potential pollution sources and catchment conditions (Cabral 2010, Ryzinska-Paier et al. 2014). Furthermore surface waters are a big challenge for automated detection devices in a technical point of view due to the high sediment load during event conditions. This presentation shows results gained form two years of monitoring in an experimental catchment (HOAL) dominated by agricultural land use. Two enzymatic measurement devices are operated parallel at the catchment outlet to test the reproducibility and precision of the method. Data from continuous GLUC monitoring under both base flow and event conditions is compared with reference samples analyzed by standardized laboratory methods for fecal pollution detection (e.g. ISO 16649-1, Colilert18). It is shown that rapid enzymatic on-site GLUC determination can successfully be operated from a technical point of view for surface water quality monitoring under the observed catchment conditions. The comparison of enzyme activity with microbiological standard analytics reveals distinct differences in the dynamic of the signals during event conditions. Cabral J. P. S. (2010) "Water Microbiology. Bacterial Pathogens and Water" International Journal of

  13. Interannual climate variability and spatially heterogeneous improvement of agricultural management impede detection of a decreasing trend in nitrate pollution in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Fovet, Ophélie; Dupas, Rémi; Durand, Patrick; Gascuel-Odoux, Chantal; Gruau, Gérard; Hamon, Yannick; Petitjean, Patrice

    2016-04-01

    Despite widespread implementation of the nitrate directive in the European Union since the 1990s, the impact on nitrate concentration in rivers is limited (Bouraoui and Grizzetti, 2011). To assess whether this lack of response is due to the long time lags of nitrate transfer or to inadequate programs of measure, long term river and groundwater monitoring data are necessary. This study analyses 15 years of daily nitrate concentration data at the outlet of an intensively farmed catchment in Western France (Kervidy-Naizin, 5 km²) and quarterly nitrate concentration data in the groundwater of two hillslopes equipped with piezometers (Kerroland and Gueriniec) within the same catchment. In this catchment groundwater contribution to annual stream flow is dominant. The objectives of this study were to i) disentangle the influence of interannual climate variability and improvement of agricultural practices (i.e. reduction in N surplus) in the stream chemistry and ii) discuss the reasons for slow catchment recovery from nitrate pollution by comparing trends in groundwater and stream concentrations. Analysis of stream data showed that flow-weighted mean annual concentration at the outlet of the Kervidy-Naizin catchment has decreased by 1.2 mg NO3- l-1 yr-1 from 1999 to 2015. This decrease was slow but significant (p value < 0.01) even though interannual climate variability (i.e. annual cumulated runoff) added noise to the signal: i) deviation in the linear model of nitrate decrease with time was negatively correlated with annual runoff (r = -0.54, p < 0.01) and ii) local minimums in the nitrate time series were coincident with local maximums in the annual runoff. Thus high runoff during wet years led to dilution of the nitrate originating from groundwater, which added variability to the signal of linear decrease in stream concentration. Analysis of groundwater data showed a significant and sharp decrease in nitrate concentration in the Kerroland piezometer transect (4.0 mg

  14. Concentration patterns of agricultural pesticides and urban biocides in surface waters of a catchment of mixed land use

    NASA Astrophysics Data System (ADS)

    Stamm, C.; Wittmer, I.; Bader, H.-P.; Scheidegger, R.; Alder, A.; Lück, A.; Hanke, I.; Singer, H.

    2009-04-01

    Organic pesticides and biocides that are found in surface waters, can originate from agricultural and urban sources. For a long time, agricultural pesticides have received substantially more attention than biocidal compounds from urban use like material protection or in-can preservatives (cosmetics etc.). Recent studies however revealed that the amounts of urban biocides used may exceed those of agricultural pesticides. This study aims at comparing the input of several important pesticides and biocides into a small Swiss stream with a special focus on loss events triggered by rainfall. A set of 16 substances was selected to represent urban and agricultural sources. The selected substances are either only used as biocides (irgarol, isothiazolinones, IPBC), as pesticides (atrazine, sulcotrione, dichlofluanid, tolylfluanid) or have a mixed use (isoproturon, terbutryn, terbutylazine, mecoprop, diazinon, carbendazim) The study catchment has an area of 25 km2 and is inhabited by about 12'000 people. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a wastewater treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. The results, based on more than 500 analyzed samples, revealed distinct concentration patterns for different compounds and sources. Agricultural pesticides exhibited a strong seasonality as expected based on the application periods. During the first one or two rain events after application the concentrations reached up to several thousand ng/l during peak flow (atrazine, isoproturon). The temporal patterns of urban biocides were more diverse. Some compounds obviously stem from permanent sources independent of rainfall because they were found mostly in the outlet of the wastewater

  15. Using 137Cs technique to quantify soil erosion and deposition rates in an agricultural catchment in the black soil region, Northeast China

    NASA Astrophysics Data System (ADS)

    Fang, Haiyan; Sun, Liying; Qi, Deli; Cai, Qiangguo

    2012-10-01

    Soil erosion significantly affects the productive black soil region in Northeast China. Quantification of the soil erosion is necessary for designing efficient degradation control strategies. 137Cs measurements undertaken on 61 sampling points collected within a 28.5 ha agricultural catchment in the black soil region of Northeast China were used to establish the magnitude and spatial pattern of soil redistribution rates as well as sediment budget within the catchment. Estimated soil redistribution rates using the Mass Balance Model 2 (MBM2) ranged from - 56.8 to 171.4 t ha- 1 yr- 1 for the sampling points that were verified by means of both runoff plot data and pedological investigation. Erosion generally occurred behind the shelterbelts, especially in the ephemeral gully susceptible areas, while deposition mainly occurred along the shelterbelts and at the catchment outlet. In the study catchment, 69% of the eroded sediments came from the slopes and 31% the ephemeral gullies. Sediments deposited along the shelterbelts at a rate of ca. 78 t yr- 1 and ca. 33 t yr- 1 at the catchment outlet. The gross soil loss rate for the catchment was - 4.4 t ha- 1 yr- 1 with a sediment delivery ratio of 53%. The mean rate of - 14.5 t ha- 1 yr- 1 in the erosion areas was much higher than the tolerable value, suggesting that effective soil conservation measures are urgently required to reduce the severe black soil loss for sustainable management of the soil resource.

  16. An Assessment of Readiness and Barriers towards ICT Programme Implementation: Perceptions of Agricultural Extension Officers in Indonesia

    ERIC Educational Resources Information Center

    Purnomo, Sutrisno Hadi; Lee, Yi-Hsuan

    2010-01-01

    This study investigates agricultural extension officers' perception of readiness and barriers towards implementation of ICT programme. Data were gathered from 312 extension officers affiliated with public organisations of the Ministry of Agriculture in four regencies of Indonesia. Descriptive statistics, exploratory and confirmatory factor…

  17. Hydrologic controls on the sources and dynamics of dissolved organic matter in an agricultural catchment in the Central Valley, California (U.S.A.)

    NASA Astrophysics Data System (ADS)

    Dyda, R. Y.; Hernes, P. J.; Spencer, R. G.; Pellerin, B. A.; Bergamaschi, B. A.

    2008-12-01

    The influence of agricultural practices on the dynamics of dissolved organic matter (DOM) cycling in river systems is poorly understood. We investigated molecular compositions of DOM at 14 sites in an agriculturally-impacted catchment (Willow Slough; 415 km2) under several different flow regimes over the course of two years in order to investigate the influence of sub-catchments on the biogeochemistry at the mouth of the catchment. The Willow Slough catchment area includes eastern foothills of the inner Coast Range to the alluvial plains and encompasses diverse land uses, including natural grasslands, orchards, viticulture and pasture, all draining toward the Sacramento River. Knowledge of the composition of DOM composition is crucial, as dissolved organic carbon (DOC) can form EPA-regulated carcinogenic compounds during the drinking water disinfection process and is therefore considered a drinking water constituent of concern. Willow Slough offers the opportunity to examine carbon source, cycling and transportation through multiple flowpaths and land uses that are common in Californian agricultural watersheds. As a constituent of DOM, lignin phenols provide information on the source, composition, quality and degradation state of DOM. Uniquely derived from vascular plants, lignin phenols can be used to distinguish between angiosperm and gymnosperm tissues and carbon-normalized yields can offer insight on the proportion of vascular plant-derived carbon versus in-situ production. Throughout the Willow Slough watershed, ratios of syringyl to vanillyl and cinnamyl to vanillyl lignin phenols show that the vascular plant component of DOM can be primarily attributed to non-woody angiosperm tissues. Lower lignin phenol concentrations and carbon-normalized yields were observed in the headwaters (0.1-0.6 mg/100mg OC and 2.6-33 μg/L) versus the mouth (0.7-2.0 mg/100mg OC and 25-72 μg/L), indicating that mid-catchment tributaries play important roles in determining the

  18. Solute transport dynamics in small, shallow groundwater-dominated agricultural catchments: insights from a high-frequency, multisolute 10 yr-long monitoring study

    NASA Astrophysics Data System (ADS)

    Aubert, A. H.; Gascuel-Odoux, C.; Gruau, G.; Akkal, N.; Faucheux, M.; Fauvel, Y.; Grimaldi, C.; Hamon, Y.; Jaffrézic, A.; Lecoz-Boutnik, M.; Molénat, J.; Petitjean, P.; Ruiz, L.; Merot, P.

    2013-04-01

    High-frequency, long-term and multisolute measurements are required to assess the impact of human pressures on water quality due to (i) the high temporal and spatial variability of climate and human activity and (ii) the fact that chemical solutes combine short- and long-term dynamics. Such data series are scarce. This study, based on an original and unpublished time series from the Kervidy-Naizin headwater catchment (Brittany, France), aims to determine solute transfer processes and dynamics that characterise this strongly human-impacted catchment. The Kervidy-Naizin catchment is a temperate, intensive agricultural catchment, hydrologically controlled by shallow groundwater. Over 10 yr, five solutes (nitrate, sulphate, chloride, and dissolved organic and inorganic carbon) were monitored daily at the catchment outlet and roughly every four months in the shallow groundwater. The concentrations of all five solutes showed seasonal variations but the patterns of the variations differed from one solute to another. Nitrate and chloride exhibit rather smooth variations. In contrast, sulphate as well as organic and inorganic carbon is dominated by flood flushes. The observed nitrate and chloride patterns are typical of an intensive agricultural catchment hydrologically controlled by shallow groundwater. Nitrate and chloride originating mainly from organic fertilisers accumulated over several years in the shallow groundwater. They are seasonally exported when upland groundwater connects with the stream during the wet season. Conversely, sulphate as well as organic and inorganic carbon patterns are not specific to agricultural catchments. These solutes do not come from fertilisers and do not accumulate in soil or shallow groundwater; instead, they are biogeochemically produced in the catchment. The results allowed development of a generic classification system based on the specific temporal patterns and source locations of each solute. It also considers the stocking period

  19. Atmospheric NH3 and NO2 concentration and nitrogen deposition in an agricultural catchment of Eastern China.

    PubMed

    Yang, Rong; Hayashi, Kentaro; Zhu, Bin; Li, Feiyue; Yan, Xiaoyuan

    2010-09-15

    To assess the atmospheric environmental impacts of anthropogenic reactive nitrogen in the fast-developing Eastern China region, we measured atmospheric concentrations of nitrogen dioxide (NO(2)) and ammonia (NH(3)) as well as the wet deposition of inorganic nitrogen (NO(3)(-) and NH(4)(+)) and dissolved organic nitrogen (DON) levels in a typical agricultural catchment in Jiangsu Province, China, from October 2007 to September 2008(.) The annual average gaseous concentrations of NO(2) and NH(3) were 42.2 microg m(-3) and 4.5 microg m(-3) (0 degree C, 760 mm Hg), respectively, whereas those of NO(3)(-), NH(4)(+), and DON in the rainwater within the study catchment were 1.3, 1.3, and 0.5 mg N L(-1), respectively. No clear difference in gaseous NO(2) concentrations and nitrogen concentrations in collected rainwater was found between the crop field and residential sites, but the average NH(3) concentration of 5.4 microg m(-3) in residential sites was significantly higher than that in field sites (4.1 microg m(-3)). Total depositions were 40 kg N ha(-1) yr(-1) for crop field sites and 30 kg N ha(-1) yr(-1) for residential sites, in which dry depositions (NO(2) and NH(3)) were 7.6 kg N ha(-1) yr(-1) for crop field sites and 1.9 kg N ha(-1) yr(-1) for residential sites. The DON in the rainwater accounted for 16% of the total wet nitrogen deposition. Oxidized N (NO(3)(-) in the precipitation and gaseous NO(2)) was the dominant form of nitrogen deposition in the studied region, indicating that reactive forms of nitrogen created from urban areas contribute greatly to N deposition in the rural area evaluated in this study. PMID:20624633

  20. HYDROGEOLOGIC CONTROLS ON NITRATE TRANSPORT IN A SMALL AGRICULTURAL CATCHMENT, IOWA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of subsurface lithology on nitrate loss in stream riparian zones are recognized but little attention has been focused on similar processes occurring in upland agricultural settings. In this paper, we evaluated hydrogeologic controls on nitrate transport processes occurring in a small 7.6 ha ...

  1. Optimization based trade-off analysis of biodiesel crop production for managing a German agricultural catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In agricultural production, the existence of multiple trade-offs among several conflicting objectives, such as food production, water quantity, water quality, biodiversity and ecosystem services, is well known. However, quantification of the trade-offs among objectives in bioenergy crop production i...

  2. Lacustrine wetland in an agricultural catchment: nitrogen removal and related biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Balestrini, R.; Arese, C.; Delconte, C.

    2007-09-01

    The role of specific catchment areas, such as the soil-river or lake interfaces, in removing or buffering the flux of N from terrestrial to aquatic ecosystems is globally recognized but the extreme variability of microbiological and hydrological processes make it difficult to predict the extent to which different wetlands function as buffer systems. In this paper we evaluate the degree to which biogeochemical processes in a lacustrine wetland are responsible for the nitrate removal from ground waters feeding Candia Lake (Northern Italy). A transect of 18 piezometers was installed perpendicular to the shoreline, in a sub-unit formed by 80 m of poplar plantation, close to a crop field and 30 m of reed swamp. The chemical analysis revealed a drastic NO3-N ground water depletion from the crop field to the lake, with concentrations decreasing from 15-18 mg N/l to the detection limit within the reeds. Patterns of Cl, SO4, O2, NO2-N, HCO3 and DOC suggest that the metabolic activity of bacterial communities, based on the differential use of electron donors and acceptors in redox reactions is the key function of this system. The significant inverse relationship found between NO3-N and HCO3 is a valuable indicator of the denitrification activity. The pluviometric regime, the temperature, the organic carbon availability and the hydrogeomorphic properties are the main environmental factors affecting the N transformations in the studied lacustrine ecosystem.

  3. Lacustrine wetland in an agricultural catchment: nitrogen removal and related biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Balestrini, R.; Arese, C.; Delconte, C.

    2008-03-01

    The role of specific catchment areas, such as the soil-river or lake interfaces, in removing or buffering the flux of N from terrestrial to aquatic ecosystems is globally recognized but the extreme variability of microbiological and hydrological processes make it difficult to predict the extent to which different wetlands function as buffer systems. In this paper we evaluate the degree to which biogeochemical processes in a lacustrine wetland are responsible for the nitrate removal from ground waters feeding Candia Lake (Northern Italy). A transect of 18 piezometers was installed perpendicular to the shoreline, in a sub-unit formed by 80 m of poplar plantation, close to a crop field and 30 m of reed swamp. The chemical analysis revealed a drastic NO3--N ground water depletion from the crop field to the lake, with concentrations decreasing from 15-18 mg N/l to the detection limit within the reeds. Patterns of Cl-, SO42-, O2, NO2--N, HCO3- and DOC suggest that the metabolic activity of bacterial communities, based on the differential use of electron donors and acceptors in redox reactions is the key function of this system. The significant inverse relationship found between NO3--N and HCO3- is a valuable indicator of the denitrification activity. The pluviometric regime, the temperature, the organic carbon availability and the hydrogeomorphic properties are the main environmental factors affecting the N transformations in the studied lacustrine ecosystem.

  4. Effectiveness of Conservation Measures in Reducing Runoff and Soil Loss Under Different Magnitude-Frequency Storms at Plot and Catchment Scales in the Semi-arid Agricultural Landscape.

    PubMed

    Zhu, T X

    2016-03-01

    In this study, multi-year stormflow data collected at both catchment and plot scales on an event basis were used to evaluate the efficiency of conservation. At the catchment scale, soil loss from YDG, an agricultural catchment with no conservation measures, was compared with that from CZG, an agricultural catchment with an implementation of a range of conservation measures. With an increase of storm recurrence intervals in the order of <1, 1-2, 2-5, 5-10, 10-20, and >20 years, the mean event sediment yield was 639, 1721, 5779, 15191, 19627, and 47924 t/km(2) in YDG, and was 244, 767, 3077, 4679, 8388, and 15868 t/km(2) in CZG, which represented a reduction effectiveness of 61.8, 55.4, 46.7, 69.2, 57.2, and 66.8 %, respectively. Storm events with recurrence intervals greater than 2 years contributed about two-thirds of the total runoff and sediment in both YDG and CZG catchments. At the plot scale, soil loss from one cultivated slopeland was compared with that from five conservation plots. The mean event soil loss was 1622 t/km(2) on the cultivated slopeland, in comparison to 27.7 t/km(2) on the woodland plot, 213 t/km(2) on the grassland plot, 467 t/km(2) on the alfalfa plot, 236 t/km(2) on the terraceland plot, and 642 t/km(2) on the earthbank plot. Soil loss per unit area from all the plots was significantly less than that from the catchments for storms of all categories of recurrence intervals. PMID:26645075

  5. Effectiveness of Conservation Measures in Reducing Runoff and Soil Loss Under Different Magnitude-Frequency Storms at Plot and Catchment Scales in the Semi-arid Agricultural Landscape

    NASA Astrophysics Data System (ADS)

    Zhu, T. X.

    2016-03-01

    In this study, multi-year stormflow data collected at both catchment and plot scales on an event basis were used to evaluate the efficiency of conservation. At the catchment scale, soil loss from YDG, an agricultural catchment with no conservation measures, was compared with that from CZG, an agricultural catchment with an implementation of a range of conservation measures. With an increase of storm recurrence intervals in the order of <1, 1-2, 2-5, 5-10, 10-20, and >20 years, the mean event sediment yield was 639, 1721, 5779, 15191, 19627, and 47924 t/km2 in YDG, and was 244, 767, 3077, 4679, 8388, and 15868 t/km2 in CZG, which represented a reduction effectiveness of 61.8, 55.4, 46.7, 69.2, 57.2, and 66.8 %, respectively. Storm events with recurrence intervals greater than 2 years contributed about two-thirds of the total runoff and sediment in both YDG and CZG catchments. At the plot scale, soil loss from one cultivated slopeland was compared with that from five conservation plots. The mean event soil loss was 1622 t/km2 on the cultivated slopeland, in comparison to 27.7 t/km2 on the woodland plot, 213 t/km2 on the grassland plot, 467 t/km2 on the alfalfa plot, 236 t/km2 on the terraceland plot, and 642 t/km2 on the earthbank plot. Soil loss per unit area from all the plots was significantly less than that from the catchments for storms of all categories of recurrence intervals.

  6. Modeling concentration patterns of agricultural and urban micropollutants in surface waters in catchment of mixed land use

    NASA Astrophysics Data System (ADS)

    Stamm, C.; Scheidegger, R.; Bader, H. P.

    2012-04-01

    Organic micropollutants detected in surface waters can originate from agricultural and urban sources. Depending on the use of the compounds, the temporal loss patterns vary substantially. Therefore models that simulate water quality in watersheds of mixed land use have to account for all relevant sources. We present here simulation results of a transport model that describes the dynamic of several biocidal compounds as well as the behaviour of human pharmaceuticals. The model consists of the sub-model Rexpo simulating the transfer of the compounds from the point of application to the stream in semi-lumped manner. The river sub-model, which is programmed in the Aquasim software, describes the fate of the compounds in the stream. Both sub-models are process-based. The Rexpo sub-model was calibrated at the scale of a small catchment of 25 km2, which is inhabited by about 12'000 people. Based on the resulting model parameters the loss dynamics of two herbicides (atrazine, isoproturon) and a compound of mixed urban and agricultural use (diuron) were predicted for two nested catchment of 212 and 1696 km2, respectively. The model output was compared to observed time-series of concentrations and loads obtained for the entire year 2009. Additionally, the fate of two pharmaceuticals with constant input (carbamazepine, diclofenac) was simulated for improving the understanding of possible degradation processes. The simulated loads and concentrations of the biocidal compounds differed by a factor of 2 to 3 from the observations. In general, the seasonal patterns were well captured by the model. However, a detailed analysis of the seasonality revealed substantial input uncertainty for the application of the compounds. The model results also demonstrated that for the dynamics of rain-driven losses of biocidal compounds the semi-lumped approach of the Rexpo sub-model was sufficient. Only for simulating the photolytic degradation of diclofenac in the stream the detailed

  7. Measuring fallout radionuclides to constrain the origin and the dynamics of suspended sediment in an agricultural drained catchment (Loire River basin, France)

    NASA Astrophysics Data System (ADS)

    Le Gall, Marion; Evrard, Olivier; Foucher, Anthony; Laceby, J. Patrick; Salvador-Blanes, Sébastien; Lefèvre, Irène; Cerdan, Olivier; Ayrault, Sophie

    2015-04-01

    Soil erosion reaches problematic levels in agricultural areas of Northwestern Europe where tile drains may accelerate sediment transfer to rivers. This supply of large quantities of fine sediment to the river network leads to the degradation of water quality by increasing water turbidity, filling reservoirs and transporting contaminants. Agricultural patterns and landscapes features have been largely modified by human activities during the last century. To investigate erosion and sediment transport in lowland drained areas, a small catchment, the Louroux (24 km²), located in the French Loire River basin was selected. In this catchment, channels have been reshaped and more than 220 tile drains outlets have been installed after World War II. As a result, soil erosion and sediment fluxes strongly increased. Sediment supply needs to be better understood by quantifying the contribution of sources and the residence times of particles within the catchment. To this end, a network of river monitoring stations was installed, and fallout radionuclides (Cs-137, excess Pb-210 and Be-7) were measured in rainwater (n=3), drain tile outlets (n=4), suspended sediment (n=15), soil surface (n=30) and channel bank samples (n=15) between January 2013 and February 2014. Cs-137 concentrations were used to quantify the contribution of surface vs. subsurface sources of sediment. Results show a clear dominance of particles originating from surface sources (99 ± 1%). Be-7 and excess Pb-210 concentrations and calculation of Be-7/excess Pb-210 ratios in rainfall and suspended sediment samples were used to estimate percentages of recently eroded sediment in rivers. The first erosive winter storm mainly exported sediment depleted in Be-7 that likely deposited on the riverbed during the previous months. Then, during the subsequent floods, sediment was directly eroded and exported to the catchment outlet. Our results show the added value of combining spatial and temporal tracers to characterize

  8. Spatio-temporal variability of the molecular fingerprint of soil dissolved organic matter in a headwater agricultural catchment

    NASA Astrophysics Data System (ADS)

    Jeanneau, Laurent; Pierson-Wickmann, Anne-Catherine; Jaffrezic, Anne; Lambert, Thibault; Gruau, Gérard

    2013-04-01

    Dissolved organic matter (DOM) is implied in (i) ecosystem services such as the support of biodiversity, (ii) the alteration of the drinkable water quality by formation of trihalomethane and (iii) the transfer of micropollutants from soils to rivers. Moreover, since DOM connects soils and oceans that are interacting with the atmosphere, understanding its biogeochemistry will help in investigating the carbon cycle and in creating strategies to mitigate climate change. DOM in headwater stream ecosystems is mainly inherited from allochtonous inputs with different reservoirs being mobilized during storm and interstorm events at the scale of an hydrological year. Those changes in DOM reservoirs, if accompanied by composition and reactivity changes, may impact DOM ecosystem services and drinking water production processes. Elucidating the compositional changes due to changes in the source of DOM in rivers has thus become a important axis of DOM research. The aim of this study is to test the ability of the molecular tools of the organic geochemistry and more specifically the combination of thermochemiolysis and gas chromatography - mass spectrometry (THM-GC-MS) to (i) link the variability of the river DOM composition to different DOM reservoirs in catchment soils and (ii) provide hypothesis on the nature and the mechanisms of formation (microbial growth, litter decomposition) of those reservoirs. This analytical method seems particularly adapted since it allows the differentiation between vegetal and microbial inputs and the determination of the extent of the biodegradation process of biomolecules such as lignin. To test this method, the molecular fingerprint of soil DOM has been investigated in the wetland area of a small (500 ha) agricultural catchment (the so-called Kervidy-Naizin catchment) located in Brittany, western France. The soil DOM was sampled fortnightly at three depths using zero-tension lysimeters during the hydrological year 2010-2011. The samples were

  9. Evaporation over a Heterogeneous Mixed Savanna-Agricultural Catchment using a Distributed Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Ceperley, N. C.; Mande, T.; Barrenetxea, G.; Vetterli, M.; Yacouba, H.; Repetti, A.; Parlange, M. B.

    2010-12-01

    Small scale rain fed agriculture is the primary livelihood for a large part of the population of Burkina Faso. Regional climate change means that this population is becoming increasingly vulnerable. Additionally, as natural savanna is converted for agriculture, hydrological systems are observed to become less stable as infiltration is decreased and rapid runoff is increased to the detriment of crop productivity, downstream populations and local water sources. The majority of the Singou River Basin, located in South East Burkina Faso is managed by hunting reserves, geared to maintaining high populations of wild game; however, residents surrounding the protected areas have been forced to intensify agriculture that has resulted in soil degradation as well as increases in the frequency and severity of flooding and droughts. Agroforestry, or planting trees in cultivated fields, has been proposed as a solution to help buffer these negative consequences, however the specific hydrologic behavior of the watershed land cover is unknown. We have installed a distributed sensor network of 17 Sensorscope wireless meteorological stations. These stations are dispersed across cultivated rice and millet fields, natural savanna, fallow fields, and around agroforestry fields. Sensorscope routes data through the network of stations to be delivered by a GPRS connection to a main server. This multi hop network allows data to be gathered over a large area and quickly adapts to changes in station performance. Data are available in real time via a website that can be accessed by a mobile phone. The stations are powered autonomously by small photovoltaic panels. This deployment is the first time that these meteorological stations have been used on the African continent. Initial calibration with measures from 2 eddy covariance stations allows us to calculate the energy balance at each of the Sensorscope stations. Thus, we can observe variation in evaporation over the various land cover in the

  10. Sulphate leaching from diffuse agricultural and forest sources in a large central European catchment during 1900-2010.

    PubMed

    Kopáček, Jiří; Hejzlar, Josef; Porcal, Petr; Posch, Maximilian

    2014-02-01

    Using dynamic, mass budget, and empirical models, we quantified sulphate-sulphur (SO4-S) leaching from soils in a large central European catchment (upper Vltava river, Czech Republic) over a 110-year period (1900-2010). SO4-S inputs to soils with synthetic fertilisers and atmospheric deposition increased in the 1950s-1980s, then rapidly decreased (~80%), and remained low since the middle 1990s. The proportion of drained agricultural land rapidly increased from 4 to 43% between the 1950s and 1990s; then the draining ability of the system slowly decreased due to its ageing. Sulphate concentrations in the Vltava exhibited similar trends as the external SO4-S inputs, suggesting that they could be explained by changes in atmospheric and fertiliser S inputs. The available data and modelling, however, showed that (i) internal SO4-S sources (mineralization of soil organic S in the drained agricultural land), (ii) a hysteresis in SO4-S leaching from forest soils (a net S retention at the high S inputs and then a net release at the lowered inputs), and (iii) hydrology must be taken into account. An empirical model was then employed, based on parameters representing hydrology (discharge), external SO4-S sources (inputs by synthetic fertilisers and atmospheric deposition), and internal SO4-S sources (mineralization related to soil drainage). The model explained 84% of the observed variability in annual SO4-S concentrations in the Vltava river during 1900-2010 and showed that forest soils were a net sink (105 kg ha(-1)) while agricultural land was a net source (55 kg ha(-1)) of SO4-S during 1960-2010. In the late 1980s, forest soils changed from a sink to a source of S, and the present release of SO4-S accumulated in forest soils thus delays recovery of surface waters from acidification, while S losses from agricultural soils increase the risk of future S deficiency in S-demanding crops. PMID:24176702

  11. Risk assessment of surface water and groundwater pollution through agricultural activity on the catchment area of the Shelek River

    NASA Astrophysics Data System (ADS)

    Zubairov, Bulat; Dautova, Assel

    2015-04-01

    Agricultural activity in rural areas of Kazakhstan can create a potential risk of surface and groundwater pollution. In our contribution, we will focus on the risk assessment of surface water and groundwater pollution in the catchment area of the Shelek River basin in southeast Kazakhstan. Since soviet time, in the research area an intensive cultivation of tobacco was performed which means to use a big amount of pesticides during the growing-process. Therefore, this research was conducted in order to receive reliable data for management decisions justification and for practical testing of approach which is recommended by WHO for drinking water supply based on risks mapping. For our study, the soil and water samples from tobacco fields, artesian spring, and surface water source were taken for analysis on pesticides content. The samples were investigated in laboratory of Centre of Sanitary and Epidemiological Expertise of Almaty city (CSEE) according to approved methods from the national standards which are accepted in Kazakhstan. For the first time, in artesian spring small amount of nitrate pollution was found whose groundwater is one of the drinking water supplies of the region.

  12. Evaluating the critical source area concept of phosphorus loss from soils to water-bodies in agricultural catchments.

    PubMed

    Shore, M; Jordan, P; Mellander, P-E; Kelly-Quinn, M; Wall, D P; Murphy, P N C; Melland, A R

    2014-08-15

    Using data collected from six basins located across two hydrologically contrasting agricultural catchments, this study investigated whether transport metrics alone provide better estimates of storm phosphorus (P) loss from basins than critical source area (CSA) metrics which combine source factors as well. Concentrations and loads of P in quickflow (QF) were measured at basin outlets during four storm events and were compared with dynamic (QF magnitude) and static (extent of highly-connected, poorly-drained soils) transport metrics and a CSA metric (extent of highly-connected, poorly-drained soils with excess plant-available P). Pairwise comparisons between basins with similar CSA risks but contrasting QF magnitudes showed that QF flow-weighted mean TRP (total molybdate-reactive P) concentrations and loads were frequently (at least 11 of 14 comparisons) more than 40% higher in basins with the highest QF magnitudes. Furthermore, static transport metrics reliably discerned relative QF magnitudes between these basins. However, particulate P (PP) concentrations were often (6 of 14 comparisons) higher in basins with the lowest QF magnitudes, most likely due to soil-management activities (e.g. ploughing), in these predominantly arable basins at these times. Pairwise comparisons between basins with contrasting CSA risks and similar QF magnitudes showed that TRP and PP concentrations and loads did not reflect trends in CSA risk or QF magnitude. Static transport metrics did not discern relative QF magnitudes between these basins. In basins with contrasting transport risks, storm TRP concentrations and loads were well differentiated by dynamic or static transport metrics alone, regardless of differences in soil P. In basins with similar transport risks, dynamic transport metrics and P source information additional to soil P may be required to predict relative storm TRP concentrations and loads. Regardless of differences in transport risk, information on land use and

  13. Mapping Zn, Cu and Cd contents at the small catchment level after dispersion of contaminants by agricultural practices

    NASA Astrophysics Data System (ADS)

    Vidal Vázquez, E.; Mirás-Avalos, J. M.; Paz-Ferreiro, J.

    2009-04-01

    Dispersion of trace metals into the rural environment through the use of sewage sludge, fertilizers and manure has been worldwide reported. In El Abelar (Coruña province, Spain), pig slurry was discharged during years intensively into an agricultural field by means of a device which constituted a point source of contamination. The application point was located near the head of an elementary basin, so that slurry was dispersed by runoff into neighboring grassland and maize fields. In addition, diffuse pollution was also present in the study area as a consequence of cattle grazing. Water quality was monitored during and after slurry application at the outlet of a small catchment (about 10.7 ha in surface) draining the study fields. High levels of nutrients, including heavy metals, were found in drainage water. The main objectives of this paper are to determine the spatial variability of Cu, Zn and Cd as extracted by NO3H, EDTA and Ca2Cl and to evaluate the risk of accumulation of these heavy metals at the small catchment level. A set of 55 soil samples were taken from the top soil layer (0-20 cm) of the studied catchment, following a random sampling scheme. Fe, Mn, Cu, Zn and Cd contents were determined i) after digestion by nitric acid in a microwave (USEPA-SW-846 3051) ii) after extraction with EDTA and iii) after extraction with Cl2Ca. Element contents in the extracts were determined by ICP-MS. Summary statistics indicate that variability in Cu, Zn and Cd contents over the study area was very high. For example, after NO3H digestion Zn contents ranged from 29.66 to 141.77 3 mg kg-1 and Cu contents varied from 10.45 to 72.7 3 mg kg-1. High Cu and Zn contents result from accumulation as a consequence of slurry discharge. Also, some hot spots with high levels of Cd (> 3 mg kg-1 after NO3H) with respect to background values were recorded. Geostatistics provides all necessary tools to analyze the spatial variability of soil properties over a landscape. The spatial

  14. Comparing three gap filling methods for eddy covariance crop evapotranspiration measurements within a hilly agricultural catchment

    NASA Astrophysics Data System (ADS)

    Boudhina, Nissaf; Prévot, Laurent; Zitouna Chebbi, Rim; Mekki, Insaf; Jacob, Frédéric; Ben Mechlia, Netij; Masmoudi, Moncef

    2015-04-01

    Hilly watersheds are widespread throughout coastal areas around the Mediterranean Basin. They experience agricultural intensification since hilly topographies allow water-harvesting techniques that compensate for rainfall storage, water being a strong limiting factor for crop production. Their fragility is likely to increase with climate change and human pressure. Within semi-arid hilly watershed conditions, evapotranspiration (ETR) is a major term of both land surface energy and water balances. Several methods allow determining ETR, based either on direct measurements, or on estimations and forecast from weather and soil moisture data using simulation models. Among these methods, eddy covariance technique is based on high-frequency measurements of fluctuations of wind speed and air temperature / humidity, to directly determine the convective fluxes between land surface and atmosphere. In spite of experimental and instrumental progresses, datasets of eddy covariance measurements often experience large portions of missing data. The latter results from energy power failure, experimental maintenance, instrumental troubles such as krypton hygrometer malfunctioning because of air humidity, or quality assessment based filtering in relation to spatial homogeneity and temporal stationarity of turbulence within surface boundary layer. This last item is all the more important as hilly topography, when combined with strong winds, tends to increase turbulence within surface boundary layer. The main objective of this study is to establish gap-filling procedures to provide complete chronicles of eddy-covariance measurements of crop evapotranspiration (ETR) within a hilly agricultural watershed. We focus on the specific conditions induced by the combination of hilly topography and wind direction, by discriminating between upslope and downslope winds. The experiment was set for three field configurations within hilly conditions: two flux measurement stations (A, B) were installed

  15. Water and Nutrient Balances in a Large Tile-Drained Agricultural Catchment: A Distributed Modeling Study

    SciTech Connect

    Li, Hongyi; Sivapalan, Murugesu; Tian, Fuqiang; Liu, Dengfeng

    2010-11-16

    This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

  16. A classification of drainage and macropore flow in an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Heppell, C. M.; Worrall, F.; Burt, T. P.; Williams, R. J.

    2002-01-01

    This paper uses a variety of multivariate statistical techniques in order to improve current understanding of the antecedent and rainfall controls on drainage characteristics for an agricultural underdrained clay site. Using the dataset obtained from a two-year hillslope study at Wytham (Oxfordshire, UK) a number of patterns in the nature and style of drainage events were explored. First, using principal components analysis, a distinction was drawn between drainflow controlled by antecedent conditions and drainflow controlled by rainfall characteristics. Dimensional analysis then distinguished between two further types of drainflow event: antecedent limited events (ALE) and non-antecedent limited events (NALE). These were drainflow events requiring a minimum antecedent hydraulic head to occur (ALE) and events that occurred in response to rainfall irrespective of the antecedent conditions, because the rainfall was either of high enough intensity or duration to prompt a response in drainflow (NALE). 2. The dataset also made possible a preliminary investigation into the controls on and types of macropore flow at the site. Principal components analysis identified that rainfall characteristics were more important than antecedent conditions in generating high proportions of macropore flow in drainflow. Of the rainfall characteristics studied, rainfall amount and intensity were the dominant controls on the amount of macropore flow, with duration as a secondary control. Two styles of macropore flow were identified: intensity-driven and duration-driven. Intensity-driven events are characterized by rainfall of high intensity and short duration. During such events the amount of macropore flow is proportional to the rainfall intensity and the interaction between macropore and matrix flow is kinetically limited. The second style of macropore flow is characterized by long-duration events. For these events the amount of macropore flow approaches a maximum value whatever the

  17. Comparative analyses of factors determining soil erosion rates based on network of Mediterranean monitored catchments for the innovative, adaptive and resilient agriculture of the future

    NASA Astrophysics Data System (ADS)

    Smetanová, Anna; Le Bissonnais, Yves; Raclot, Damien; Perdo Nunes, João; Licciardello, Feliciana; Mathys, Nicolle; Latron, Jérôme; Rodríguez Caballero, Emilio; Le Bouteiller, Caroline; Klotz, Sébastien; Mekki, Insaf; Gallart, Francesc; Solé Benet, Albert; Pérez Gallego, Nuria; Andrieux, Patrick; Jantzi, Hugo; Moussa, Roger; Planchon, Olivier; Marisa Santos, Juliana

    2015-04-01

    In order to project the soil erosion response to climate change in the fragile Mediterranean region it is inevitable to understand its existing patterns. Soil erosion monitoring on a catchment scale enables to analyse temporal and spatial variability of soil erosion and sediment delivery, while the integrating study of different catchments is often undertaken to depicther the general patterns. In this study, eight small catchments (with area up to 1,32 km2), representative for the western part of the Mediterranean region (according to climate, bedrock, soils and main type of land use) were compared. These catchments, grouped in the R-OS Med Network were situated in France (3), Spain (2), Portugal (1), Italy (1) and Tunisia (1). The average precipitation ranged between 236 to 1303 mm·a-1 and mean annual sediment yield varied 7.5 to 6900 Mg·km-2·a-1. The complex databes was based on more than 120 years of hydrological and sediment data, with series between 3 and 29 years long. The variability of sediment data was described on annual and monthly basis. The relationship between the sediment yield and more than 35 factors influencing the sediment yield including the characteristics of climate, topography, rainfall, runoff, land use, vegetation and soil cover, connectivity and dominant geomorphic processes, was studied. The preliminary results confirmed the differences in rainfall, runoff and sediment response, and revealed both the similarities and differences in soil erosion responses of the catchments. They are further dependent on the variability of factors themselves, with important contribution of the state of soil properties, vegetation cover and land use. Anna Smetanová has received the support of the European Union, in the framework of the Marie-Curie FP7 COFUND People Programme, through the award of an AgreenSkills' fellowship (under grant agreement n° 267196)

  18. Supervised Agricultural Experience Programmes (SAEP) and Work Linked Education (WLE): Panacea for Empowering Youths and Preventing Joblessness

    ERIC Educational Resources Information Center

    Famiwole, Remigius O.

    2015-01-01

    Youths from Nigerian schools and tertiary institutions are usually unemployable after schooling because they are not empowered with the required saleable skills to earn them a job or with which to establish as entrepreneurs. This paper examines the relevance of Supervised Agricultural Experience Programme (SAEP) and Work Linked Education (WLE) as…

  19. Student Perceptions of Agricultural Education Programme Processes at Selected High Schools in KwaZulu-Natal Province, South Africa

    ERIC Educational Resources Information Center

    Kidane, T. T.; Worth, S. H.

    2014-01-01

    Purpose: This study investigates student perceptions of different aspects of Agricultural Education and Training (AET) programme processes that have been offered in secondary schools by the formal educational sector in the province of KwaZulu-Natal, South Africa. The study seeks to identify the existing shortcomings in the implementation of the…

  20. Nitrate sinks and sources as controls of spatio-temporal water quality dynamics in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Gascuel-Odoux, Chantal; Durand, Patrick; Weiler, Markus

    2016-02-01

    Several controls are known to affect water quality of stream networks during flow recession periods, such as solute leaching processes, surface water-groundwater interactions as well as biogeochemical in-stream turnover processes. Throughout the stream network, combinations of specific water and solute export rates and local in-stream conditions overlay the biogeochemical signals from upstream sections. Therefore, upstream sections can be considered functional units which could be distinguished and ordered regarding their relative contribution to nutrient dynamics at the catchment outlet. Based on snapshot sampling of flow and nitrate concentrations along the stream in an agricultural headwater during the summer flow recession period, we determined spatial and temporal patterns of water quality for the whole stream. A data-driven, in-stream-mixing-and-removal model was developed and applied for analysing the spatio-temporal in-stream retention processes and their effect on the spatio-temporal fluxes of nitrate from subcatchments. Thereby, we have been able to distinguish quantitatively between nitrate sinks, sources per stream reaches, and subcatchments, and thus we could disentangle the overlay of nitrate sink and source signals. For nitrate sources, we determined their permanent and temporal impact on stream water quality and for nitrate sinks, we found increasing nitrate removal efficiencies from upstream to downstream. Our results highlight the importance of distinct nitrate source locations within the watershed for in-stream concentrations and in-stream removal processes, respectively. Thus, our findings contribute to the development of a more dynamic perception of water quality in streams and rivers concerning ecological and sustainable water resource management.

  1. Sulfonylurea herbicides in an agricultural catchment basin and its adjacent wetland in the St. Lawrence River basin.

    PubMed

    de Lafontaine, Yves; Beauvais, Conrad; Cessna, Allan J; Gagnon, Pierre; Hudon, Christiane; Poissant, Laurier

    2014-05-01

    The use of sulfonylurea herbicides (SU) has increased greater than 100 times over the past 30 years in both Europe and North America. Applied at low rates, their presence, persistence and potential impacts on aquatic ecosystems remain poorly studied. During late-spring to early fall in 2009-2011, concentrations of 9 SU were assessed in two agricultural streams and their receiving wetland, an enlargement of the St. Lawrence River (Canada). Six SU in concentrations >LOQ (10 ng L(-1)) were detected in 10% or less of surface water samples. Rimsulfuron was detected each year, sulfosulfuron and nicosulfuron in two years and the others in one year only, suggesting that application of specific herbicides varied locally between years. Detection frequency and concentrations of SU were not significantly associated with total precipitation which occurred 1 to 5d before sampling. Concentrations and fate of SU differed among sites due to differences in stream dynamics and water quality characteristics. The persistence of SU in catchment basin streams reflected the dissipation effects associated with stream discharge. Maximum concentrations of some SU (223 and 148 ng L(-1)) were occasionally above the baseline level (100 ng L(-1)) for aquatic plant toxicity, implying potential toxic stress to flora in the streams. Substantially lower concentrations (max 55 ng L(-1)) of SU were noted at the downstream wetland site, likely as a result from dilution and mixing with St. Lawrence River water, and represent less toxicological risk to the wetland flora. Sporadic occurrence of SU at low concentrations in air and rain samples indicated that atmospheric deposition was not an important source of herbicides to the study area. PMID:24534695

  2. Nitrous oxide and methane emission in an artificial wetland treating polluted runoff from an agricultural catchment

    NASA Astrophysics Data System (ADS)

    Mander, Ülo; Tournebize, Julien; Soosaar, Kaido; Chaumont, Cedric; Hansen, Raili; Muhel, Mart; Teemusk, Alar; Vincent, Bernard

    2015-04-01

    An artificial wetland built in 2010 to reduce water pollution in a drained agricultural watershed showed real potential for pesticide and nitrate removal. The 1.2 ha off-shore wetland with a depth of from 0.1 to 1 m intercepts drainage water from a 450 ha watershed located near the village of Rampillon (03°03'37.3'' E, 48°32'16.7'' N, 70 km south-east of Paris, France). A sluice gate installed at the inlet makes it possible to close the wetland during the winter months (December - March), when no pesticides are applied and rainfall events are more frequent. The flow entering the wetland fluctuates from 0 to 120 L/s. The wetland is partially covered by Carex spp., Phragmites australis, Juncus conglomeratus, Typha latifolia and philamentous algae. Since 2011, an automatic water quality monitoring system measures water discharge, temperature, dissolved O2, conductivity pH, NO3- and DOC in both inlet and outlet. In May 2014, an automatic weather station and Campbell Irgason system for the measurement of CO2 and H2O fluxes were installed in the middle of the wetland. In May and November 2014 one-week high frequency measurement campaigns were conducted to study N2O and CH4 fluxes using 6 manually operated opaque floating static chambers and 12 floating automatic dynamic chambers. The latter were operated via multiplexer and had an incubation time of 5 minutes, whereas the gas flow was continuously measured using the Aerodyne TILDAS quantum cascade laser system. During the campaign, the reduction of NO3- concentration was measured in nine reactor pipes. Also, water samples were collected for N2O and N2 isotope analysis, and sediments were collected for potential N2 emission measurements. In May, the hydraulic retention time (HRT) was 30 days, and the average NO3- concentration decreased from 24 in the inflow to 0 mg/L in the outflow. Methane flux was relatively high (average 1446, variation 0.2-113990 μg CH4-C m-2 h-1), while about 2/3 was emitted via ebullition

  3. Interactive Effects of Storms, Drought, and Weekly Land Cover Changes on Water Quality Patterns in an Agricultural-dominated Subtropical Catchment in New Zealand

    NASA Astrophysics Data System (ADS)

    Julian, J.; Owsley, B.; de Beurs, K.; Hughes, A.

    2013-12-01

    Rivers are the funnels of landscapes, with the quality of water at the catchment outlet reflecting interactions among geomorphic processes, vegetation characteristics, weather patterns, and anthropogenic land uses. The impacts of changing climate and land cover on water quality are not straightforward; but instead, are set by the interaction of numerous landscape components at multiple spatiotemporal scales. In agricultural-dominated subtropical landscapes such as the Hoteo River Catchment in northern North Island of New Zealand, the land surface can be very dynamic, responding quickly to storms, drought, forest clearings, and grazing practices. In order to capture these short-term fluctuations, we created an 8-day land disturbance index for the catchment using MODIS Nadir BRDF-adjusted reflectance (NBAR) data (500 meter resolution) from 2000 to 2013. We also fused this time-series with Landsat TM/ETM surface reflectance data (30 meter resolution) to more precisely capture the location and extent of these land disturbances. This high-resolution land disturbance time-series was then compared to daily rainfall, daily river discharge, and monthly water samples to assess the effects of changing weather and land cover on a suite of water quality variables including water clarity, turbidity, ammonium (NH4), nitrate (NO3), total nitrogen (TN), dissolved reactive phosphate (DRP), total phosphorus (TP), and fecal coliforms. Forest clearings in the early part of our study period created the most intense land disturbances, which led to elevated turbidity and DRP during subsequent storms. Pasture areas during drought were also characterized by high disturbance indices, particularly in 2013 - the worst drought on record for northern New Zealand. Seasonal effects on land disturbance and water quality were also detected, especially for water clarity and turbidity. From 2011 to 2013, river discharge and turbidity from three sub-catchments were measured at 5-minute intervals to

  4. Prediction of dissolved reactive phosphorus losses from small agricultural catchments: calibration and validation of a parsimonious model

    NASA Astrophysics Data System (ADS)

    Hahn, C.; Prasuhn, V.; Stamm, C.; Lazzarotto, P.; Evangelou, M. W. H.; Schulin, R.

    2013-01-01

    Eutrophication of surface waters due to diffuse phosphorus (P) losses continues to be a severe water quality problem world-wide, causing the loss of ecosystem functions of the respective water bodies. Phosphorus in runoff often originates from a small fraction of a catchment only. Targeting mitigation measures to these critical source areas (CSA) is expected to be most efficient and cost-effective, but requires suitable tools. Here we investigated the capability of the parsimonious Rainfall-Runoff-Phosphorus (RRP) model to identify CSA in grassland-dominated catchments based on readily available soil and topographic data. After simultaneous calibration on runoff data from four small hilly catchments on the Swiss Plateau, the model was validated on a different catchment in the same region without further calibration. The RRP model adequately simulated the discharge and dissolved reactive P (DRP) export from the validation catchment. Sensitivity analysis showed that the model predictions were robust with respect to the classification of soils into "poorly drained" and "well drained", based on the available soil map. Comparing spatial hydrological model predictions with field data from the validation catchment provided further evidence that the assumptions underlying the model are valid and that the model adequately accounts for the dominant P export processes in the target region. Thus, the parsimonious RRP model is a valuable tool that can be used to determine CSA. Despite the considerable predictive uncertainty regarding the spatial extent of CSAs the RRP can provide guidance for the implementation of mitigation measures. The model helps to identify those parts of a catchment where high DRP losses are expected or can be excluded with high confidence. Legacy P was predicted to be the dominant source for DRP losses and thus, in combination with hydrologic active areas, a high risk for water quality.

  5. Prediction of dissolved reactive phosphorus losses from small agricultural catchments: calibration and validation of a parsimonious model

    NASA Astrophysics Data System (ADS)

    Hahn, C.; Prasuhn, V.; Stamm, C.; Lazzarotto, P.; Evangelou, M. W. H.; Schulin, R.

    2013-10-01

    Eutrophication of surface waters due to diffuse phosphorus (P) losses continues to be a severe water quality problem worldwide, causing the loss of ecosystem functions of the respective water bodies. Phosphorus in runoff often originates from a small fraction of a catchment only. Targeting mitigation measures to these critical source areas (CSAs) is expected to be most efficient and cost-effective, but requires suitable tools. Here we investigated the capability of the parsimonious Rainfall-Runoff-Phosphorus (RRP) model to identify CSAs in grassland-dominated catchments based on readily available soil and topographic data. After simultaneous calibration on runoff data from four small hilly catchments on the Swiss Plateau, the model was validated on a different catchment in the same region without further calibration. The RRP model adequately simulated the discharge and dissolved reactive P (DRP) export from the validation catchment. Sensitivity analysis showed that the model predictions were robust with respect to the classification of soils into "poorly drained" and "well drained", based on the available soil map. Comparing spatial hydrological model predictions with field data from the validation catchment provided further evidence that the assumptions underlying the model are valid and that the model adequately accounts for the dominant P export processes in the target region. Thus, the parsimonious RRP model is a valuable tool that can be used to determine CSAs. Despite the considerable predictive uncertainty regarding the spatial extent of CSAs, the RRP can provide guidance for the implementation of mitigation measures. The model helps to identify those parts of a catchment where high DRP losses are expected or can be excluded with high confidence. Legacy P was predicted to be the dominant source for DRP losses and thus, in combination with hydrologic active areas, a high risk for water quality.

  6. Hydroclimatic Controls on the Seasonal and Inter-Annual Variability of Dissolved Phosphorus Concentration in a Lowland Agricultural Catchment

    NASA Astrophysics Data System (ADS)

    Dupas, R.; Gascuel-odoux, C.; Grimaldi, C.; Gruau, G.

    2014-12-01

    We investigated soluble reactive phosphorus (SRP) at the outlet of a lowland agricultural catchment (Kervidy-Naizin, France) to identify the hydroclimatic controls on the seasonal and inter-annual variability in concentrations. Six years of stream data have been used, including a regular 6-daily sampling and high-frequency monitoring of 52 floods. Both on an annual basis and during flood events, distinct export dynamics for SRP and particulate phosphorus (PP) revealed that SRP transport mechanism was independent from PP (Dupas et al., submitted). During most flood events, discharge-SRP hystereses were anticlockwise, which suggests that SRP was transferred to the stream via subsurface flow. Groundwater rise in wetland soils was likely the cause of this transfer, through the hydrological connectivity it created between the stream and P-rich soil horizons. SRP concentrations were highest in the beginning of the hydrological year (period A), when the stream started to flow again after the dry summer season and water table fluctuated in the wetland domain. Thus, wetland soils seemed to be a major source of SRP. Concentrations during period A were higher after a long summer period than after a short one, which suggest that a pool of labile P was constituted in soils during the dry summer period. During winter (period B), SRP concentration generally decreased compared to period A, both during floods and interflood. This could be due to depletion of a soil P pool in the wetland domain and/or dilution by deep groundwater with low P concentration from the upland domain. Concentration during period B barely decreased compared to A during wet years, probably due to increased connectivity with soils from the upland domain in wet conditions. During spring (period C), SRP concentration increased during baseflow periods. The possible mechanisms causing the release of SRP could involve reduction of Fe oxide-hydroxides in wetland soils or in-stream processes. At the same time, SRP

  7. Indirect nitrous oxide emissions from surface water bodies in a lowland arable catchment: a significant contribution to agricultural greenhouse gas budgets?

    PubMed

    Outram, Faye N; Hiscock, Kevin M

    2012-08-01

    In the UK agriculture is by far the largest source of nitrous oxide (N(2)O) emissions. Direct N(2)O emissions as a result of nitrogen (N) application to soils have been well documented in the UK, whereas indirect emissions produced in surface waters and groundwaters from leached N are much less understood with limited data to support IPCC emission factors. Indirect emissions were studied in surface waters in the Upper Thurne, a lowland drained arable catchment in eastern England. All surface waters were found to have dissolved N(2)O concentrations above that expected if in equilibrium with ambient concentrations, demonstrating all surface waters were acting as a source of N(2)O. The drainage channels represented 86% of the total indirect N(2)O flux, followed by wetland areas, 11%, and the river, 3%. The dense drainage network was found to have the highest dissolved N(2)O concentrations of all the water bodies studied with a combined N(2)O flux of 16 kg N(2)O-N per day in March 2007. Such indirect fluxes are comparable to direct fluxes per hectare and represent a significant proportion of the total N(2)O flux for this catchment. Separate emission factors were established for the three different surface water types within the same catchment, suggesting that the one emission factor used in the Intergovernmental Panel on Climate Change (IPCC) methodology for predicting all indirect N(2)O emissions is inappropriate. PMID:22789002

  8. REXPO: A catchment model designed to understand and simulate the loss dynamics of plant protection products and biocides from agricultural and urban areas

    NASA Astrophysics Data System (ADS)

    Wittmer, I. K.; Bader, H.-P.; Scheidegger, R.; Stamm, C.

    2016-02-01

    During rain events, biocides and plant protection products are transported from agricultural fields but also from urban sources to surface waters. Originally designed to be biologically active, these compounds may harm organisms in aquatic ecosystems. Although several models allow either urban or agricultural storm events to be predicted, only few combine these two sources, and none of them include biocide losses from building envelopes. This study therefore aims to develop a model designed to predict water and substance flows from urban and agricultural sources to surface waters. We developed a model based on physical principles for water percolation and substance flow including micro- (also called matrix-) and macropore-flows for the agricultural areas together with a model representing sources, sewer systems and a wastewater treatment plant for urban areas. In a second step, the combined model was applied to a catchment where an extensive field study had been conducted. The modelled and measured discharge and compound results corresponded reasonably well in terms of quantity and dynamics. The total cumulative discharge was only slightly lower than the total measured discharge (factor 0.94). The total modelled losses of the agriculturally used herbicide atrazine were slightly lower (∼25%) than the measured losses when the soil pore water distribution coefficient (describing the partition between soil particles and pore water) (Kd) was kept constant and slightly higher if it was increased with time. The modelled urban losses of diuron from facades were within a factor of three with respect to the measured values. The results highlighted the change in importance of the flow components during a rain event from urban sources during the most intensive rain period towards agricultural ones over a prolonged time period. Applications to two other catchments, one neighbouring and one on another continent showed that the model can be applied using site specific data for

  9. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  10. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  11. Dissolved and Particulate Organic Carbon Transport, Loads and Relationships from Catchments in the Dryland Agricultural Region of the Inland Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Boylan, R. D.; Brooks, E. S.

    2012-12-01

    It has long been understood that soil organic matter (SOM) plays important role in the chemistry of agricultural soils. Promoting both cation exchange capacity and water retention, SOM also has the ability to sequester atmospheric carbon adding to a soils organic carbon content. Increasing soil organic carbon in the dryland agricultural region of the Inland Pacific Northwest is not only good for soil health, but also has the potential to mitigate greenhouse gas emissions. Implementing strategies that minimizing the loss of soil carbon thus promoting carbon sequestration require a fundamental understanding of the dominant hydrologic flow paths and runoff generating processes in this landscape. Global fluxes of organic carbon from catchments range from 0.4-73,979 kg C km-2 year-1 for particulate organic carbon and 1.2-56,946 kg C km-2 year-1 for dissolved organic carbon (Alvarez-Cobelas, 2010). This small component of the global carbon cycle has been relatively well studied but there have yet to be any studies that focus on the dryland agricultural region of the Inland Pacific Northwest. In this study event based samples were taken at 5 sites across the Palouse Basin varying in land use and management type as well as catchment size, ranging from 1km2 to 7000 km2. Data collection includes streamflow, suspended sediment, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), particulate organic carbon (POC), dissolved organic nitrogen (TN), and nitrate concentrations as well as soil organic carbon (SOC) from distributed source areas. It is predicted that management type and streamflow will be the main drivers for DOC and POC concentrations. Relationships generated and historic data will then be used in conjunction with the Water Erosion Prediction Project (WEPP) to simulate field scale variability in the soil moisture, temperature, surface saturation, and soil erosion. Model assessment will be based on both surface runoff and sediment load measured at the

  12. Impacts of land use and climate variability on hydrology in an agricultural catchment on the Loess Plateau of China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land use and climate are the two major factors directly influencing catchment hydrology; however, it is difficult to separate the effects of the two. Using the SWAT (Soil and Water Assessment Tools) model, we assessed the impacts of land use change and climate variability on surface hydrology (runof...

  13. Urban and agricultural contribution of annual loads of glyphosate and AMPA towards surface waters at the Orge River catchment scale (France)

    NASA Astrophysics Data System (ADS)

    Botta, Fabrizio; Chevreuil, Marc; Blanchoud, Hélène

    2010-05-01

    The general use of pesticides in the Orge Basin, located in the southern part of the Paris suburb (France), is damaging surface water quality. Consequently, an increase in the water supply costs is registered by the water supply agencies that are situated downstream the Orge confluence with the Seine River. In this catchment, high uses of glyphosate are registered for fallow fields (upstream part) and for roadway weed control (downstream part). The proportion of glyphosate coming from these two zones was not well known, along with the double source of its metabolite AMPA originated from the degradation of some detergent phosphonates. The aim of this work was firstly to identify the potential sources of glyphosate and AMPA in urban sectors (such as sewerage system inputs) and in agricultural areas and to quantify the origins of urban pesticides pathways towards surface waters at the basin scale. The new approach of this project was to collect information at three different scales to establish a first step of modeling. At the basin scale, 1 year of surface water monitoring at the outlet of the Orge River was useful to establish the inputs towards the Seine River. At the urban catchment scale, the investigations have permitted to record glyphosate and AMPA loads transferred by storm waters and by wastewaters. Loads were estimated during and out of application calendar, in different hydrological conditions such as rainfall with high intensity or dry conditions. Impact of WWTP on surface water was also demonstrated. The third phase of this work was the interpretation of agricultural inputs from two different agricultural catchments of the Orge River. The results showed the impact of urban uses of glyphosate upon the Orge River contamination with annual loads from 100 times higher from the urban zone than from the agricultural one. Storm sewers were recognized to be the main way for glyphosate transfer towards surface waters. A budget of glyphosate and AMPA inputs and

  14. Impact of nitrogenous fertilizers on carbonate dissolution in small agricultural catchments: Implications for weathering CO 2 uptake at regional and global scales

    NASA Astrophysics Data System (ADS)

    Perrin, Anne-Sophie; Probst, Anne; Probst, Jean-Luc

    2008-07-01

    The goal of this study was to highlight the occurrence of an additional proton-promoted weathering pathway of carbonate rocks in agricultural areas where N-fertilizers are extensively spread, and to estimate its consequences on riverine alkalinity and uptake of CO 2 by weathering. We surveyed 25 small streams in the calcareous molassic Gascogne area located in the Garonne river basin (south-western France) that drain cultivated or forested catchments for their major element compositions during different hydrologic periods. Among these catchments, the Hay and the Montoussé, two experimental catchments, were monitored on a weekly basis. Studies in the literature from other small carbonate catchments in Europe were dissected in the same way. In areas of intensive agriculture, the molar ratio (Ca + Mg)/HCO 3 in surface waters is significantly higher (0.7 on average) than in areas of low anthropogenic pressure (0.5). This corresponds to a decrease in riverine alkalinity, which can reach 80% during storm events. This relative loss of alkalinity correlates well with the NO3- content in surface waters. In cultivated areas, the contribution of atmospheric/soil CO 2 to the total riverine alkalinity (CO 2 ATM-SOIL/HCO 3) is less than 50% (expected value for carbonate basins), and it decreases when the nitrate concentration increases. This loss of alkalinity can be attributed to the substitution of carbonic acid (natural weathering pathway) by protons produced by nitrification of N-fertilizers (anthropogenic weathering pathway) occurring in soils during carbonate dissolution. As a consequence of these processes, the alkalinity over the last 30 years shows a decreasing trend in the Save river (one of the main Garonne river tributaries, draining an agricultural catchment), while the nitrate and calcium plus magnesium contents are increasing. We estimated that the contribution of atmospheric/soil CO 2 to riverine alkalinity decreased by about 7-17% on average for all the studied

  15. Developments in the Curriculum for the Swedish MSc Programme in Agriculture.

    ERIC Educational Resources Information Center

    Malmfors, Birgitta; Nilsson, Kjell-Arne

    In Sweden, higher education in agriculture is provided exclusively by the Swedish University of Agricultural Sciences. The 130 students admitted to the Master of Science program in agriculture annually may choose to specialize in one of six specialty areas (plant science, animal science, food science, biotechnology, economics, and engineering),…

  16. Sediment sources in a small agricultural catchment: A composite fingerprinting approach based on the selection of potential sources

    NASA Astrophysics Data System (ADS)

    Zhou, Huiping; Chang, Weina; Zhang, Longjiang

    2016-08-01

    Fingerprinting techniques have been widely used as a reasonable and reliable means for investigating sediment sources, especially in relatively large catchments in which there are significant differences in surface materials. However, the discrimination power of fingerprint properties for small catchments, in which the surface materials are relatively homogeneous and human interference is marked, may be affected by fragmentary or confused source information. Using fingerprinting techniques can be difficult, and there is still a need for further studies to verify the effectiveness of such techniques in these small catchments. A composite fingerprinting approach was used in this study to investigate the main sources of sediment output, as well as their relative contributions, from a small catchment (30 km2) with high levels of farming and mining activities. The impact of the selection of different potential sediment sources on the derivation of composite fingerprints and its discrimination power were also investigated by comparing the results from different combinations of potential source types. The initial source types and several samples that could cause confusion were adjusted. These adjustments improved the discrimination power of the composite fingerprints. The results showed that the composite fingerprinting approach used in this study had a discriminatory efficiency of 89.2% for different sediment sources and that the model had a mean goodness of fit of 0.90. Cultivated lands were the main sediment source. The sediment contribution of the studied cultivated lands ranged from 39.9% to 87.8%, with a mean of 76.6%, for multiple deposited sediment samples. The mean contribution of woodlands was 21.7%. Overall, the sediment contribution from mining and road areas was relatively low. The selection of potential sources is an important factor in the application of fingerprinting techniques and warrants more attention in future studies, as is the case with other

  17. Daily nitrate losses: implication on long-term river quality in an intensive agricultural catchment of southwestern france.

    PubMed

    Boithias, Laurie; Srinivasan, Raghavan; Sauvage, Sabine; Macary, Francis; Sánchez-Pérez, José Miguel

    2014-01-01

    High nitrate concentrations in streams have become a widespread problem throughout Europe in recent decades, damaging surface water and groundwater quality. The European Nitrate Directive fixed a potability threshold of 50 mg L for European rivers. The performance of the Soil and Water Assessment Tool model was assessed in the 1110-km Save catchment in southwestern France for predicting water discharge and nitrate loads and concentrations at the catchment outlet, considering observed data set uncertainty. Simulated values were compared with intensive and extensive measurement data sets. Daily discharge fitted observations (Nash-Sutcliffe efficiency coefficient = 0.61, = 0.7, and PBIAS = -22%). Nitrate simulation (1998-2010) was within the observed range (PBIAS = 10-21%, considering observed data set uncertainty). Annual nitrate load at the catchment outlet was correlated to the annual water yield at the outlet ( = 0.63). Simulated annual catchment nitrate exportation ranged from 21 to 49 kg ha depending on annual hydrological conditions (average, 36 kg ha). Exportation rates ranged from 3 to 8% of nitrogen inputs. During floods, 34% of the nitrate load was exported, which represented 18% of the 1998-2010 period. Average daily nitrate concentration at the outlet was 29 mg L (1998-2010), ranging from 0 to 270 mg L. Nitrate concentration exceeded the European 50 mg L potability threshold during 244 d between 1998 and 2010. A 20% reduction of nitrogen input reduced crop yield by between 5 and 9% and reduced by 62% the days when the 50 mg L threshold was exceeded. PMID:25602539

  18. Changes in Children's Consumption of Tomatoes through a School Lunch Programme Developed by Agricultural High-School Students

    ERIC Educational Resources Information Center

    Ishikawa, Midori; Kubota, Nozomi; Kudo, Keita; Meadows, Martin; Umezawa, Atsuko; Ota, Toru

    2013-01-01

    Objective: The purpose of the study was to discover whether tomato consumption in elementary- and middle-school students could be increased through a school lunch programme developed by agricultural high-school students acting as peer educators. Design: The high-school lunch programme included the process of growing tomatoes and providing a…

  19. PSYCHIC A process-based model of phosphorus and sediment transfers within agricultural catchments. Part 2. A preliminary evaluation

    NASA Astrophysics Data System (ADS)

    Strömqvist, J.; Collins, A. L.; Davison, P. S.; Lord, E. I.

    2008-02-01

    SummaryThis paper describes the preliminary evaluation of the PSYCHIC catchment scale (Tier 1) model for predicting the mobilisation and delivery of phosphorus (P) and suspended sediment (SS) in the Hampshire Avon (1715 km 2) and Herefordshire Wye (4017 km 2) drainage basins, in the UK, using empirical data. Phosphorus and SS transfers to watercourses in the Wye were predicted to be greater than corresponding delivery in the Avon; SS, 249 vs 33 kg ha -1 yr -1; DP, 2.57 vs 1.26 kg ha -1 yr -1; PP, 2.20 vs 0.56 kg ha -1 yr -1. The spatial pattern of the predicted transfers was relatively uniform across the Wye drainage basin, whilst in the Avon, delivery to watercourses was largely confined to the river corridors and small areas of drained land. Statistical performance in relation to predicted exports of P and SS, using criteria for relative error (RE) and root mean square error (RMSE), reflected the potential shortcomings associated with using longer-term climate data for predicting shorter-term (2002-2004) catchment response and the need to refine calculations of point source contributions and to incorporate additional river basin processes such as channel bank erosion and in-stream geochemical processing. PSYCHIC is therefore best suited to characterising longer-term catchment response.

  20. Hydrologic controls on the export dynamics of dissolved and particulate phosphorus in a lowland, headwater agricultural catchment

    NASA Astrophysics Data System (ADS)

    Dupas, Rémi; Grimaldi, Catherine; Gruau, Gérard; Gascuel-Odoux, Chantal

    2014-05-01

    Phosphorus (P) availability controls eutrophication in freshwater ecosystems, since P is generally the limiting nutrient to algal development. The contribution of diffuse P emission to surface waters is significant in intensively livestock farmed catchments as a result of high application rates of P-rich animal waste and subsequent enrichment of soils. This study investigates the transport dynamics of particulate phosphorus (PP), suspended sediments (SS), and dissolved phosphorus (DP) with the aim of elucidating the relationship between PP and DP transport mechanisms and water dynamics in lowland, headwater catchments. The selected catchment (Kervidy-Naizin catchment, France) is particularly suitable for this purpose as it benefits of a 5 years, high-frequency monitoring of PP and DP concentrations at its outlet, including data recovered both during base flow and storm periods, with the monitoring of more than 50 storm flow events. The data analysis includes interpretation of concentration-discharge relationships at the annual time scale and on an event basis, seasonal analysis of flood characteristics and empirical modeling. Annual DP and PP concentration-discharge relationships of interflood samples display a hysteretic pattern, with higher concentrations during the autumn and spring periods, and progressive decrease during winter. No hysteretic pattern is visible for interflood SS concentration, which follows a classical C=a*Qb relationship. During floods, the dynamic of PP export is similar to that of SS during most of the events: the concentration peak occurs during the rising limb of the hydrogram (clockwise hysteresis), suggesting a source close to or within the stream. The amplitude and the hysteresis' loop size for SS and PP are a function of maximum discharge and rate of change in discharge. On the contrary, there is a strong decoupling between DP and SS (and thus PP) during most of the floods (no significant correlation), with DP concentration peaks

  1. Impacts of the post-fire erosion processes compared with the agricultural erosion rates for a mountain catchment in NW Iberia

    NASA Astrophysics Data System (ADS)

    Marisa Santos, Juliana; Nunes, João Pedro; Bernard-Jannin, Léonard; Gonzalez Pelayo, Oscar; Keizer, Jan Jacob

    2014-05-01

    Mediterranean ecosystems are very vulnerable to soil erosion by water due to particular characteristics of climate, lithology and land use history. Moreover, the foreseen climate changes might worsen land degradation and desertification, in which soil erosion has been classified as one of the most important driving forces. In this context, the frequent forest fires seen in some Mediterranean regions can case disturbances to vegetation cover and enhance soil erosion processes. This work addresses this issue for the Caramulo mountain range, NW Iberia. In the past century, large land use changes occurred due to massive afforestation. Changes from mixed natural forest cover and shrublands to Pine, the introduction of Eucalyptus plantations and, more recently, a trend for the substitution of pines by eucalypts, are the evidence of a large and rapid land use change in the last decades. Forest fires started to occur as afforestation proceeded, as a consequence of the disappearance of pasturage and accumulation of highly inflammable material; they became more frequent after the 1960's and became a determinant factor for land use changes in this region. Data collection focused on the Macieira de Alcoba catchment, a headwater agro-forested catchment (94 ha) located in this region. It has a wet Mediterranean climate, with an average annual rainfall of about 1300 mm (2002-2012), concentrated in autumn and winter, while spring and summer are dryer seasons. The mean annual temperature is 14°C and in summer it can reach 35°C. The land use is mixed, with forest and agriculture lands covering respectively 60 and 35% of the catchment area, 5% being built-up areas in the village of Macieira de Alcoba. In the last decades, this catchment suffered several forest fires (in 1969, 1986, 1991, and 2011). Erosion processes are related with periods of low vegetation cover in autumn in fields with a pasture-corn rotation, but also with forest plantations after clear-cutting and especially

  2. Seed Aid for Food Security? Some Lessons from Zimbabwe's Agricultural Recovery Programme

    ERIC Educational Resources Information Center

    Foti, Richard; Muringai, Violet; Mavunganidze, Zira

    2007-01-01

    Does agricultural input aid always lead to favourable food security outcomes? This paper describes Zimbabwe's agricultural recovery program for the 2003/2004 farming season and draws some lessons that can be used in the designing and implementation of future programs. Input aid was found to be most beneficial if it is packaged together with other…

  3. Learning Our Way into Communication: The Making of the Communication and Information Strategy "with" the National Agricultural Advisory Services Programme in Uganda

    ERIC Educational Resources Information Center

    Ramirez, Ricardo

    2005-01-01

    This paper reports on the making of the Communication and Information Strategy with the National Agricultural Advisory Services Programme (NAADS) in Uganda. The NAADS is a new organization in government responsible for the implementation of a demand-driven agricultural extension approach. The new extension approach calls for fundamental changes in…

  4. Analysing the role of abandoned agricultural terraces on flood generation in a set of small Mediterranean mountain research catchments (Vallcebre, NE Spain)

    NASA Astrophysics Data System (ADS)

    Gallart, Francesc; Llorens, Pilar; Pérez-Gallego, Nuria; Latron, Jérôme

    2016-04-01

    The Vallcebre research catchments are located in NE Spain, in a middle mountain area with a Mediterranean sub-humid climate. Most of the bedrock consists of continental red lutites that are easily weathered into loamy soils. This area was intensely used for agriculture in the past when most of the sunny gentle hillslopes were terraced. The land was progressively abandoned since the mid-20th Century and most of the fields were converted to meadows or were spontaneously forested. Early studies carried out in the terraced Cal Parisa catchment demonstrated the occurrence of two types of frequently saturated areas, ones situated in downslope locations with high topographic index values, and the others located in the inner parts of many terraces, where the shallow water table usually outcrops due to the topographical modifications linked to terrace construction. Both the increased extent of saturated areas and the role of a man-made elementary drainage system designed for depleting water from the terraces suggested that terraced areas would induce an enhanced hydrological response during rainfall events when compared with non-terraced hillslopes. The response of 3 sub-catchments, of increasing area and decreasing percentage of terraced area, during a set of major events collected during over 15 years has been analysed. The results show that storm runoff depths were roughly proportional to precipitations above 30 mm although the smallest catchment (Cal Parisa), with the highest percentage of terraces, was able to completely buffer rainfall events of 60 mm in one hour without any runoff when antecedent conditions were dry. Runoff coefficients depended on antecedent conditions and peak discharges were weakly linked to rainfall intensities. Peak lag times, peak runoff rates and recession coefficients were similar in the 3 catchments; the first variable values were in the range between Hortonian and saturation overland flow and the two last ones were in the range of

  5. Selected examples of needs for long term pilot areas in Mediterranean catchments: a mountain traditional agricultural system and a large and regulated hydrographic basin in Southern Spain

    NASA Astrophysics Data System (ADS)

    José Polo, María; Herrero, Javier; Millares, Agustín; José Pérez-Palazón, María; Pimentel, Rafael; Aguilar, Cristina; Jurado, Alicia; Contreras, Eva; Gómez-Beas, Raquel; Carpintero, Miriam; Gulliver, Zacarías

    2015-04-01

    Integrated River Basin Management (IRBM) aims at planning water, land and other natural resources for an equitable and sustainable management, also capable of preserving or restoring freshwater ecosystems. Long term series of significant variables at different scales and a sound knowledge of the river basin processes are needed to establish the current state and past&future evolution of the hydrological system, soil use and vegetation distribution, and their social impacts and feedbacks. This is particularly crucial if future scenario analyses are to be performed to assess decision-making processes and adaptive plans. This work highlights the need for an adequate design and development of process-oriented monitoring systems at the basin scale in a decision-making framework. First, the hydrologic monitoring network of the Guadalfeo River Basin, in the southern face of Sierra Nevada Range (Spain), is shown, in a pilot catchment of 1300 km2 in which snow processes in Mediterranean conditions have been studied over the last ten years with a holistic approach. The network development and the main features of the dataset are described together with their use for different scientific and environmental applications; their benefits for assessing social and economic impact in the rural environment are shown from a study case in which the sustainability of ancient channels fed by snowmelt, in use since the XIIIth century for traditional irrigated crops in the mountainous area, was assessed in a future scenarios analyses. Secondly, the standard flow and water quality monitoring networks in the Guadalquivir River Basin, a large (57400 km2) and highly regulated agricultural catchment in southern Spain, are shown, and their strengths and weaknessess for an IRBM framework are analysed. Sediments and selected pollutants are used to trace soil erosion and agricultural/urban exports throughout the catchment, and the final loads to the river estuary in the Atlantic Ocean are assessed

  6. The challenge of lots of data: different ways to synthesise and visualise high frequency catchment data

    NASA Astrophysics Data System (ADS)

    Jonczyk, Jennine; Barber, Nicholas; Benskin, Claire; Snell, Maria; Deasy, Clare; Reaney, Sim; Quinn, Paul; Owen, Gareth; EdenDTC Team

    2015-04-01

    System understanding is vital for future catchment management and to inform mitigation of both flooding and DWPA. High resolution data sets collected at catchment outlets are becoming more common. They have the potential to provide new insights into how land units process water and how this influences nutrient and ecological dynamics. However, the monitoring equipment is costly to install and operate. Also, the volume of data, both temporally and spatially, presents new challenges to catchment scientists on how best to synthesise these data into a form where they can be visualised and utilised in decision making. The Eden DTC project is part of a national project funded by the UK government to provide robust evidence on how diffuse pollution can be cost-effectively managed to improve and maintain water quality in rural river catchments. The impact of multiple water quality parameters on ecosystems and sustainable food production are being studied at the catchment scale. Three focus catchments (c. 10 km2) have been selected to represent the different farming practices and geophysical characteristics across the Eden catchment, Northern England. A field experimental programme has been designed to monitor the dynamics of agricultural diffuse pollution at multiple scales using state of the art in situ sensors, which provide continuous real-time data. Data generated through this project will be used to explore these challenges and look at different ways to synthesise and visualise these data, ultimately providing a powerful communication mechanism that potentially can be used as a conduit for real holistic catchment management.

  7. Groundwater flow path dynamics and nitrogen transport potential in the riparian zone of an agricultural headwater catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream riparian zones are often thought of as areas that provide natural remediation for groundwater contaminants, especially agricultural nitrogen (N). While denitrification and vegetative uptake tend to be efficient N removal processes in slow moving shallow groundwater, these mechanisms decrease ...

  8. River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England.

    PubMed

    Neal, Colin; Neal, Margaret; Hill, Linda; Wickham, Heather

    2006-05-01

    The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive. PMID:16253306

  9. Assessment of Professional Training Programmes in International Agricultural Research Institutions: The Case of ICRAF

    ERIC Educational Resources Information Center

    Wanjiku, Julliet; Mairura, Franklin; Place, Frank

    2010-01-01

    The following survey was undertaken in 2005 to assess the effectiveness of professional training activities in international agricultural research organizations that were undertaken between 1999 and 2002 at ICRAF (International Centre for Research in Agroforestry), now World Agroforestry Centre, Nairobi. Trainees were randomly selected from…

  10. Long-term, high-frequency water quality monitoring in an agricultural catchment: insights from spectral analysis

    NASA Astrophysics Data System (ADS)

    Aubert, Alice; Kirchner, James; Faucheux, Mikael; Merot, Philippe; Gascuel-Odoux, Chantal

    2013-04-01

    The choice of sampling frequency is a key issue in the design and operation of environmental observatories. The choice of sampling frequency creates a spectral window (or temporal filter) that highlights some timescales and processes, and de-emphasizes others (1). New online measurement technologies can monitor surface water quality almost continuously, allowing the creation of very rich time series. The question of how best to analyze such detailed temporal datasets is an important issue in environmental monitoring. In the present work, we studied water quality data from the AgrHys long-term hydrological observatory (located at Kervidy-Naizin, Western France) sampled at daily and 20-minute time scales. Manual sampling has provided 12 years of daily measurements of nitrate, dissolved organic carbon (DOC), chloride and sulfate (2), and 3 years of daily measurements of about 30 other solutes. In addition, a UV-spectrometry probe (Spectrolyser) provides one year of 20-minute measurements for nitrate and DOC. Spectral analysis of the daily water quality time series reveals that our intensively farmed catchment exhibits universal 1/f scaling (power spectrum slope of -1) for a large number of solutes, confirming and extending the earlier discovery of universal 1/f scaling in the relatively pristine Plynlimon catchment (3). 1/f time series confound conventional methods for assessing the statistical significance of trends. Indeed, conventional methods assume that there is a clear separation of scales between the signal (the trend line) and the noise (the scatter around the line). This is not true for 1/f noise, since it overestimates the occurrence of significant trends. Our results raise the possibility that 1/f scaling is widespread in water quality time series, thus posing fundamental challenges to water quality trend analysis. Power spectra of the 20-minute nitrate and DOC time series show 1/f scaling at frequencies below 1/day, consistent with the longer-term daily

  11. Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting

    NASA Astrophysics Data System (ADS)

    Foucher, Anthony; Laceby, Patrick J.; Salvador-Blanes, Sébastien; Evrard, Olivier; Le Gall, Marion; Lefèvre, Irène; Cerdan, Olivier; Rajkumar, Vignesh; Desmet, Marc

    2015-12-01

    suspended sediment loads on riverine systems in similar lowland drained agricultural catchments.

  12. Dynamics of nitrate and chloride during storm events in agricultural catchments with different subsurface drainage intensity (Indiana, USA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grids of perforated pipe buried beneath many poorly drained agricultural fields in the Midwestern U.S. are believed to “short circuit” pools of nitrate-laden soil water and shallow groundwater directly into streams that eventually discharge to the Mississippi River. Although much is known about the ...

  13. Trace Element Distribution in Stream Bed Sediments Within AN Agricultural Catchment of the Broadkill River Watershed, Delaware, USA

    NASA Astrophysics Data System (ADS)

    Oyewumi, O.; Schreiber, M. E.

    2011-12-01

    This project examined the impact of long-term litter application on the chemical signatures of trace metals (As, Cu, Zn,) and nutrient (P) in river sediments of the Broadkill River watershed within the Delmarva Peninsula, a region of intense poultry production. Twenty-seven (27) sediment samples were collected from Broadkill River drainage systems and analyzed for acid and soluble extractable elements as well as basic soil parameters such as particle size, organic matter and soluble salts. Results showed that concentrations of the trace elements in stream sediments are approximately log-normally distributed, with concentrations increasing from upstream headwaters to downstream reaches draining predominantly agricultural areas. Using GIS maps with overlays of hydrology and land use activity, correlations between the concentrations of As, Cu, Zn and P and agricultural activities within the watershed were examined. Results indicate positive correlation between the trace elements but the connection to specific regions of agricultural land use is not clearly defined. Trace elements were also positively correlated with percent of clay and silt particles, indicating partitioning of these elements to finer grain sizes. Calculations of element enrichment factors and the geoaccumulation index revealed that most of the sediment samples were not enriched in trace elements with respect to our reference samples. However, trace element concentrations in sediments increased downgradient, suggesting that they may be influenced by anthropogenic activities within the watershed.

  14. Indirect emissions and isotopologue signatures of N2O from agricultural drainage water of a Pleistocene lowland catchment in North-Eastern Germany

    NASA Astrophysics Data System (ADS)

    Weymann, D.; Well, R.; Kahle, P.; Tiemeyer, B.; Flessa, H.

    2011-12-01

    Artificial drainage of low- and wetlands is a common practice in many agricultural regions to facilitate crop production. Agricultural drainage water was shown to be supersaturated with nitrous oxide (N2O), a major greenhouse gas thought to contribute to global warming and to the destruction of stratospheric ozone. Therefore, drainage of agricultural land has potential for indirect N2O emissions which are a highly uncertain component of the global N2O budget. This case study focuses on these emissions and further tries to unravel the source processes of N2O as well as the impact of its hydrological controls by applying an isotopologue approach. The research area was an intensively tile drained agricultural catchment embedded in the Pleistocene lowland of the federal state Mecklenburg-Vorpommern (North-Eastern Germany). Water sampling was conducted during the consecutive hydrological winter periods 2007/2008 and 2008/2009 by sampling a collector drain outlet and an adjacent drainage ditch. Besides concentrations of dissolved N2O and NO3- we determined the isotopologue signatures of N2O by measuring δ15Nbulk and δ18O as well as the 15N 'site preference', which characterizes the intramolecular distribution of the N isotopes within the asymmetric N2O molecule and is a promising tool to distinguish between the main source processes of N2O, nitrification and denitrification. The investigated hydrological winter periods varied considerably concerning the weather and hydrological conditions. During the comparatively wet winter period 2007/2008, indirect N2O emissions accounted for 0.17 kg N2O-N ha-1 a-1 and were thus higher than during the colder and comparatively dry 2008/2009 period, where we found 0.12 kg N2O-N ha-1 a-1. The emission factors for both sampling periods were 0.23 % and 0.17 % of the N input, respectively, and therefore in good agreement with the current IPCC default value of 0.25 %. The isotopologue signatures of N2O reflected the different hydrological

  15. The impact of cattle access on ecological water quality in streams: Examples from agricultural catchments within Ireland.

    PubMed

    Conroy, E; Turner, J N; Rymszewicz, A; O'Sullivan, J J; Bruen, M; Lawler, D; Lally, H; Kelly-Quinn, M

    2016-03-15

    Unrestricted cattle access to rivers and streams represent a potentially significant localised pressure on freshwater systems. However there is no consensus in the literature on the occurrence and extent of impact and limited research has examined the effects on aquatic biota in the humid temperate environment examined in the present study. Furthermore, this is one of the first times that research consider the potential for cattle access impacts in streams of varying water quality in Northern Europe. We investigated the effects of cattle access on macroinvertebrate communities and deposited fine sediment levels, in four rivers of high/good and four rivers of moderate water quality status which drain, low gradient, calcareous grassland catchments in Ireland. We assessed the temporal variability in macroinvertebrates communities across two seasons, spring and autumn. Site specific impacts were evident which appeared to be influenced by water quality status and season. All four high/good water status rivers revealed significant downstream changes in community structure and at least two univariate metrics (total richness and EPT richness together with taxon, E and EPT abundance). Two of the four moderate water status rivers showed significant changes in community structure, abundance and richness metrics and functional feeding groups driven in the main by downstream increases in collectors/gatherers, shredders and burrowing taxa. These two moderate water status rivers had high or prolonged livestock activity. In view of these findings, the potential for some of these sites to achieve at least high/good water quality status, as set out in the EU Water Framework Directive, may be compromised. The results presented highlight the need for additional research to further define the site specific factors and livestock management practices, under different discharge conditions, that increase the risk of impact on aquatic ecology due to these cattle-river interactions. PMID

  16. Environmental Risk Assessment of Fluctuating Diazinon Concentrations in an Urban and Agricultural Catchment Using Toxicokinetic–Toxicodynamic Modeling

    PubMed Central

    2011-01-01

    Temporally resolved environmental risk assessment of fluctuating concentrations of micropollutants is presented. We separated the prediction of toxicity over time from the extrapolation from one to many species and from acute to sublethal effects. A toxicokinetic–toxicodynamic (TKTD) model predicted toxicity caused by fluctuating concentrations of diazinon, measured by time-resolved sampling over 108 days from three locations in a stream network, representing urban, agricultural and mixed land use. We calculated extrapolation factors to quantify variation in toxicity among species and effect types based on available toxicity data, while correcting for different test durations with the TKTD model. Sampling from the distribution of extrapolation factors and prediction of time-resolved toxicity with the TKTD model facilitated subsequent calculation of the risk of undesired toxic events. Approximately one-fifth of aquatic organisms were at risk and fluctuating concentrations were more toxic than their averages. Contribution of urban and agricultural sources of diazinon to the overall risk varied. Thus using fixed concentrations as water quality criteria appears overly simplistic because it ignores the temporal dimension of toxicity. However, the improved prediction of toxicity for fluctuating concentrations may be small compared to uncertainty due to limited diversity of toxicity data to base the extrapolation factors on. PMID:21958042

  17. Environmental risk assessment of fluctuating diazinon concentrations in an urban and agricultural catchment using toxicokinetic-toxicodynamic modeling.

    PubMed

    Ashauer, Roman; Wittmer, Irene; Stamm, Christian; Escher, Beate I

    2011-11-15

    Temporally resolved environmental risk assessment of fluctuating concentrations of micropollutants is presented. We separated the prediction of toxicity over time from the extrapolation from one to many species and from acute to sublethal effects. A toxicokinetic-toxicodynamic (TKTD) model predicted toxicity caused by fluctuating concentrations of diazinon, measured by time-resolved sampling over 108 days from three locations in a stream network, representing urban, agricultural and mixed land use. We calculated extrapolation factors to quantify variation in toxicity among species and effect types based on available toxicity data, while correcting for different test durations with the TKTD model. Sampling from the distribution of extrapolation factors and prediction of time-resolved toxicity with the TKTD model facilitated subsequent calculation of the risk of undesired toxic events. Approximately one-fifth of aquatic organisms were at risk and fluctuating concentrations were more toxic than their averages. Contribution of urban and agricultural sources of diazinon to the overall risk varied. Thus using fixed concentrations as water quality criteria appears overly simplistic because it ignores the temporal dimension of toxicity. However, the improved prediction of toxicity for fluctuating concentrations may be small compared to uncertainty due to limited diversity of toxicity data to base the extrapolation factors on. PMID:21958042

  18. The seasonal dynamics of the stream sources and input flow paths of water and nitrogen of an Austrian headwater agricultural catchment.

    PubMed

    Exner-Kittridge, Michael; Strauss, Peter; Blöschl, Günter; Eder, Alexander; Saracevic, Ernis; Zessner, Matthias

    2016-01-15

    Our study examines the source aquifers and stream inputs of the seasonal water and nitrogen dynamics of a headwater agricultural catchment to determine the dominant driving forces for the seasonal dynamics in the surface water nitrogen loads and concentrations. We found that the alternating aquifer contributions throughout the year of the deep and shallow aquifers were the main cause for the seasonality of the nitrate concentration. The deep aquifer water typically contributed 75% of the total outlet discharge in the summer and 50% in the winter when the shallow aquifer recharges due to low crop evapotranspiration. The shallow aquifer supplied the vast majority of the nitrogen load to the stream due to the significantly higher total nitrogen concentration (11 mg-N/l) compared to the deep aquifer (0.50 mg-N/l). The main stream input pathway for the shallow aquifer nitrogen load was from the perennial tile drainages providing 60% of the total load to the stream outlet, while only providing 26% of the total flow volume. The diffuse groundwater input to the stream was the largest input to the stream (39%), but only supplied 27% to the total nitrogen load as the diffuse water was mostly composed of deep aquifer water. PMID:26562340

  19. Baseflow and stormflow metal fluxes from two small agricultural catchments in the Coastal Plain of the Chesapeake Bay Basin, United States

    USGS Publications Warehouse

    Miller, C.V.; Foster, G.D.; Majedi, B.F.

    2003-01-01

    Annual yields (fluxes per unit area) of Al, Mn, Fe, Ni, Cd, Pb, Zn, Cu, Cr, Co, As and Se were estimated for two small non-tidal stream catchments on the Eastern Shore of the Chesapeake Bay, United States - a poorly drained dissected-upland watershed in the Nanticoke River Basin, and a well-drained feeder tributary in the lower reaches of the Chester River Basin. Both watersheds are dominated by agriculture. A hydrograph-separation technique was used to determine the baseflow and stormflow components of metal yields, thus providing important insights into the effects of hydrology and climate on the transport of metals. Concentrations of suspended-sediment were used as a less-costly proxy of metal concentrations which are generally associated with particles. Results were compared to other studies in Chesapeake Bay and to general trends in metal concentrations across the United States. The study documented a larger than background yield of Zn and Co from the upper Nanticoke River Basin and possibly enriched concentrations of As, Cd and Se from both the upper Nanticoke River and the Chesterville Branch (a tributary of the lower Chester River). The annual yield of total Zn from the Nanticoke River Basin in 1998 was 18,000 g/km2/a, and was two to three times higher than yields reported from comparable river basins in the region. Concentrations of Cd also were high in both basins when compared to crustal concentrations and to other national data, but were within reasonable agreement with other Chesapeake Bay studies. Thus, Cd may be enriched locally either in natural materials or from agriculture.

  20. Catchment controls on solute export

    NASA Astrophysics Data System (ADS)

    Musolff, Andreas; Schmidt, Christian; Selle, Benny; Fleckenstein, Jan H.

    2015-12-01

    Dynamics of solute export from catchments can be classified in terms of chemostatic and chemodynamic export regimes by an analysis of concentration-discharge relationships. Previous studies hypothesized that distinct export regimes emerge from the presence of solute mass stores within the catchment and their connectivity to the stream. However, so far a direct link of solute export to identifiable catchment characteristics is missing. Here we investigate long-term time series of stream water quality and quantity of nine neighboring catchments in Central Germany ranging from relatively pristine mountain catchments to agriculturally dominated lowland catchments, spanning large gradients in land use, geology, and climatic conditions. Given the strong collinearity of catchment characteristics we used partial least square regression analysis to quantify the predictive power of these characteristics for median concentrations and the metrics of export regime. We can show that median concentrations and metrics of the export regimes of major ions and nutrients can indeed be inferred from catchment characteristics. Strongest predictors for median concentrations were the share of arable land, discharge per area, runoff coefficient and available water capacity in the root zone of the catchments. The available water capacity in the root zone, the share of arable land being artificially drained and the topographic gradient were found to be the most relevant predictors for the metrics of export regime. These catchment characteristics can represent the size of solute mass store such as the fraction of arable land being a measure for the store of nitrate. On the other hand, catchment characteristics can be a measure for the connectivity of these solute stores to the stream such as the fraction of tile drained land in the catchments. This study demonstrates the potential of data-driven, top down analyses using simple metrics to classify and better understand dominant controls of

  1. The Influence of temporal sampling regime on the WFD classification of catchments within the Eden Demonstration Test Catchment Project

    NASA Astrophysics Data System (ADS)

    Jonczyk, Jennine; Haygarth, Phil; Quinn, Paul; Reaney, Sim

    2014-05-01

    A high temporal resolution data set from the Eden Demonstration Test Catchment (DTC) project is used to investigate the processes causing pollution and the influence of temporal sampling regime on the WFD classification of three catchments. This data highlights WFD standards may not be fit for purpose. The Eden DTC project is part of a UK government-funded project designed to provide robust evidence regarding how diffuse pollution can be cost-effectively controlled to improve and maintain water quality in rural river catchments. The impact of multiple water quality parameters on ecosystems and sustainable food production are being studied at the catchment scale. Three focus catchments approximately 10 km2 each, have been selected to represent the different farming practices and geophysical characteristics across the Eden catchment, Northern England. A field experimental programme has been designed to monitor the dynamics of agricultural diffuse pollution at multiple scales using state of the art sensors providing continuous real time data. The data set, which includes Total Phosphorus and Total Reactive Phosphorus, Nitrate, Ammonium, pH, Conductivity, Turbidity and Chlorophyll a reveals the frequency and duration of nutrient concentration target exceedance which arises from the prevalence of storm events of increasing magnitude. This data set is sub-sampled at different time intervals to explore how different sampling regimes affects our understanding of nutrient dynamics and the ramification of the different regimes to WFD chemical status. This presentation seeks to identify an optimum temporal resolution of data for effective catchment management and to question the usefulness of the WFD status metric for determining health of a system. Criteria based on high frequency short duration events needs to be accounted for.

  2. Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture within the United States is varied and produces a large value ($200 billion in 2002) of production across a wide range of plant and animal production systems. Because of this diversity, changes in climate will likely impact agriculture throughout the United States. Climate affects crop, ...

  3. Legacy Contaminantion in UK catchments since the mid-19th century

    NASA Astrophysics Data System (ADS)

    Howden, N. J. K.; Burt, T. P.; Worrall, F.; Noacco, V.; Wagener, T.

    2014-12-01

    We present data from UK catchments to characterise impacts of industrial and agricultural development of UK river catchments since the mid-19th century. We draw heavily on the world's longest continuous water quality monitoring programme in the Thames River Basin (1868-date) and discuss the implications of both agricultural development, social and industrial change, and the impact of legislation on coupled land and water resource systems. Our review draws on both data and model analysis over a 145-year period and explores how a multitude of inter-linked drivers affects process-function and practical water resource management decision-support. Our work uncovers key drivers, catchment responses and emergent challenges for process science and regulation, with particular emphasis on the technical challenge for catchment scientists to provide both insight and workable solutions to maintain food and water security in intensively management river basins. We discuss issues of appropriate methods for both data capture and subsequent analyses to support short- and long-term decision making, and particularly considers the importance of advanced techniques to clarify uncertainties in extrapolation of short-term observations to inform long-term goals. We speculate as to future trajectories of catchment responses to current pressures, and potential pitfalls to immediate concerns that may often be at odds with overall requirements for continued use of natural resources in the future.

  4. The European Union Food Distribution programme for the Most Deprived Persons of the community, 1987-2013: From agricultural policy to social inclusion policy?

    PubMed

    Caraher, Martin

    2015-07-01

    The European Union Food Distribution programme for the Most Deprived Persons (MDP) of the community ran from 1987 until 2013. It was funded from Common Agricultural Policy budgets. The programme initially made use of surplus foods from the food mountains resulting from intervention stocks. This food was then distributed through aid agencies within member states, coordinated at a national government level. Reform of the CAP and global rises in food prices resulted in an increase in budget from €300 to €500 million Euros in 2010 with the added power to buy food on the open market. This led to a formal challenge to the scheme on the basis that buying goods on the open market shifted the emphasis from an agricultural/financial basis to a social one. A court ruling found that because the program was no longer used for removing surpluses the link to agriculture policy has become tenuous and therefore had no basis in community law. As a result of this legal challenge a number of policy compromises ensured the MDP would continue until the end of 2013 with a reduced budget. The scheme has been superseded by a new scheme in March 2014 called the Fund for European Aid to the Most Deprived (FEAD). This is seen as a social programme. The way that policy and politics developed and changed the MDP programme are set out. The article tracks its move from being an agricultural policy to a social welfare one. The key policy players and actors in this move are set out as are the changing context and policy frameworks. The replacement of the MDP by FEAD is discussed as is how intensive lobbying in 2012/13 resulted in the development of a new Fund for European Aid to the Most Deprived (FEAD). PMID:26001298

  5. The use of GIS and multi-criteria evaluation (MCE) to identify agricultural land management practices which cause surface water pollution in drinking water supply catchments.

    PubMed

    Grayson, Richard; Kay, Paul; Foulger, Miles

    2008-01-01

    Diffuse pollution poses a threat to water quality and results in the need for treatment for potable water supplies which can prove costly. Within the Yorkshire region, UK, nitrates, pesticides and water colour present particular treatment problems. Catchment management techniques offer an alternative to 'end of pipe' solutions and allow resources to be targeted to the most polluting areas. This project has attempted to identify such areas using GIS based modelling approaches in catchments where water quality data were available. As no model exists to predict water colour a model was created using an MCE method which is capable of predicting colour concentrations at the catchment scale. CatchIS was used to predict pesticide and nitrate N concentrations and was found to be generally capable of reliably predicting nitrate N loads at the catchment scale. The pesticides results did not match the historic data possibly due to problems with the historic pesticide data and temporal and spatially variability in pesticide usage. The use of these models can be extended to predict water quality problems in catchments where water quality data are unavailable and highlight areas of concern. PMID:19029721

  6. PSYCHIC A process-based model of phosphorus and sediment mobilisation and delivery within agricultural catchments. Part 1: Model description and parameterisation

    NASA Astrophysics Data System (ADS)

    Davison, Paul S.; Withers, Paul J. A.; Lord, Eunice I.; Betson, Mark J.; Strömqvist, Johan

    2008-02-01

    SummaryPSYCHIC is a process-based model of phosphorus (P) and suspended sediment (SS) mobilisation in land runoff and subsequent delivery to watercourses. Modelled transfer pathways include release of desorbable soil P, detachment of SS and associated particulate P, incidental losses from manure and fertiliser applications, losses from hard standings, the transport of all the above to watercourses in underdrainage (where present) and via surface pathways, and losses of dissolved P from point sources. The model can operate at two spatial scales, although the scientific core is the same in both cases. At catchment scale, the model uses easily available national scale datasets to infer all necessary input data whilst at field scale, the user is required to supply all necessary data. The model is sensitive to a number of crop and animal husbandry decisions, as well as to environmental factors such as soil type and field slope angle. It is envisaged that the catchment-scale model would provide the first tier of a catchment characterisation study, and would be used as a screening tool to identify areas within the catchment which may be at elevated risk of P loss. This would enable targeted data collection, involving farm visits and stakeholder discussion, which would then be followed up with detailed field-scale modelling. Both tiers allow the effects of possible mitigation options at catchment scale (Tier 1) and field scale (Tier 2) to be explored. The PSYCHIC model framework therefore provides a methodology for identifying critical source areas of sediment and P transfer in catchments and assessing what management changes are required to achieve environmental goals.

  7. A bottom up approach to implementing multi-purpose mitigation measures for reducing flood risk and improving water quality in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Wilkinson, M. E.; Quinn, P. F.; Jonczyk, J.; Burke, S.; Nicholson, A.; Barber, N.; Owen, G.; Palmer, M.

    2012-04-01

    A number of studies have suggested that there is evidence that modern land-use management practices have increased surface runoff at the local scale. There is an urgent need for interventions to reduce the risk of flooding whilst also delivering multiple benefits (doing more for less). There are many settlements, which regularly suffer from flooding, which would benefit from upstream mitigation measures. Interventions at the source of runoff generation can have a positive impact on the flood hydrograph downstream. An integrated approach to managing runoff can also have multiple benefits on pollution and ecology, which could lead to beneficial impacts at the catchment scale. Belford, a small community in Northumberland, UK has suffered from an increased number of flood events over the past ten years. There is currently support within the English and Welsh Environment Agency for sustainable flood management solutions such as storage ponds, wetlands, beaver dams and willow riparian features which are being trialled at Belford. These runoff attenuation features (RAFs) also have benefits to water quality, capture sediment and create new ecological zones. Although the process by which numerous RAFs were deployed in Belford proved initially difficult to achieve within the existing regulatory framework, an efficient uptake process is now supported by local regulators including several branches of the Environment Agency. The Belford runoff management framework provides a step by step guide to implementing mitigation measures in the Belford burn catchment and could be easily applied to other catchments at a similar scale. The approach is based on implementing mitigation measures through engaging with catchment stakeholders and using solid field science and management protocols.

  8. Emergy measures of carrying capacity and sustainability of a target region for an ecological restoration programme: a case study in Loess Hilly Region, China.

    PubMed

    Dang, Xiaohu; Liu, Guobin

    2012-07-15

    Evaluating the sustainability of a target region for an ecological restoration programme is challenging because it involves different aspects of human society and environment as well as multiple disciplines. Carrying capacity provides a useful measure of the sustainability of a given region where an ecological restoration programme is implemented. In this article, the Yangou catchment, a geomorphic unit, was used as a case study in the Loess Hilly Region of China, where emergy synthesis was used to measure the environmental resources base. The specific standard of living in terms of emergy was employed to calculate carrying capacity over the period 1998-2005 and to assess the sustainability of the Yangou catchment where an ecological restoration programme was carried out. The results of the evaluation indicated that after implementing the ecological restoration programme, there was some improvement in the environmental aspects of the Yangou catchment during the study period, suggesting that the ecological restoration programme alleviated ecological degradation. However, several emergy-based indices and the support areas also illustrated that the ecological restoration programme was not successful enough in terms of preservation and utilisation of environmental resources to enhance sustainability. This indicates that further actions are necessary on conserving environmental resources, improving the emergy input structure for agricultural production and in lifestyle changes for the local people in living in the Yangou catchment. PMID:22425879

  9. The role of historical agricultural terraces in geo-hydrological risk reduction: a case study from the Bisagno Stream Catchment (Genoa, Italy)

    NASA Astrophysics Data System (ADS)

    Faccini, Francesco; Giostrella, Paola; Paliaga, Guido; Piana, Pietro; Sacchini, Alessandro

    2016-04-01

    Terraces, traditionally sustained by dry stonewalls, occupy about thirty percent of the territory of Liguria. If constantly maintained, they effectively contribute to slow down the natural slope erosion. When no longer managed, terraces are recognized as one of the reasons for increased geomorphological risk along the slopes and, consequently, at the bottom of the valley. This study concerns the terraced landscapes of the Bisagno Stream catchment, internationally known for the recent and recurring floods which affected the city of Genoa. The Bisagno Stream catchment is an example of historical evolution of the territory both in terms of land use change and geo-hydrological risk. The catchment, whose highest point is Mount Candelozzo (1034 m), has a total area of 95 km2. In its terminal stretch the stream flows across the eastern part of Genoa city centre. It is a typical valley of the Genoa metropolitan area, with steep slopes and short times of concentration. Here the signs of the tragic floods which have affected the area since 1970 are still visible. The most recent and tragic geo-hydrological event in Liguria took place in the Bisagno Valley in October 2014. The study was carried out with a multi-temporal comparison of the terraced areas using aerial photographs and regional cartographic information. A further step will involve the analysis and classification of the terraces based on their maintenance condition and hydrogeological effectiveness, using some representative areas of the valley as cases study. The comparison between the distribution of terraces in the Bisagno valley and applied geomorphological cartography suggests the need of measures to reduce the risk according to a suitable set of priorities, including the recovery of the terraced areas and connected structures aimed to limit the accumulation of solid material along the main waterway.

  10. Physical and human influences on fluvial water quality in the Tagus river catchment, Portugal

    NASA Astrophysics Data System (ADS)

    Nunes, A.

    2009-04-01

    Rivers are important resources of drinkable water, ecosystems with a high biologic potency and places of entertainment. Water quality at the catchment scale depends on climate, geology, geomorphology, soils and mainly of land use and land cover. Different activities such as agriculture, livestock, industrial and urban drains have promoted the deterioration of the fluvial water quality. The announced climate changes, the increase of food requirements, as well as the urban concentration of people pose new challenges for the assessment and sustainable management of water quality on the catchment scale. At present about 2/3 of portuguese population live near coast, in urban centers. Since the last three decades, the largest part of the marginal agricultural land has been abandoned whilst the most productive soils have experienced an intensification on its productivity. The Tagus river catchment, with an area of 24.850 km2 only in the Portuguese territory, shows very important contrasts in climate, geology, geomorphology, land use and population density. The main objectives of this work are to evaluate and compare the surface water quality in different sub catchments of Tagus river and to contribute to a better understanding of how physical and human factors (such as geology, precipitation, temperature, runoff, land use and land cover and population density) interfere in their spatial-temporal variability. In order to achieve this issue, twenty sub catchments were selected. The chosen catchments show different locations and areas, and a quite long data series of physical, chemical and biology properties of water, such as nitrates, phosphates, dissolved oxygen, total coliforms, etc. Making use of Geographic Information System (GIS) tools, a database was created for each sub-catchment containing all the physical and human characteristics. Afterwards, statistical analysis was carried out by using SPSS programme (11.0 for Windows. One-way analysis of variance and the Tukey

  11. Investigating catchment-scale hysteretic behaviour of nutrients at annual and individual storm time-resolutions.

    NASA Astrophysics Data System (ADS)

    Lloyd, Charlotte; Freer, Jim; Johnes, Penny; Collins, Adrian

    2013-04-01

    The European Water Framework Directive (WFD) requires that all water bodies should be maintained at, or raised to, good ecological status, driven by improved integrated catchment management. Therefore, it is necessary to implement cost-effective mitigation strategies to reduce pollution from nutrients and improve overall water quality. If successful mitigation strategies are to be designed then it is imperative that catchment scale responses to environmental and anthropogenic changes are better understood. Against this background, this presentation investigates changes in hysteretic behaviours of nutrients in response to different environmental drivers using high resolution monitoring techniques. Observations of hysteretic behaviour can provide insights into the dominant flow pathways of pollutants. Therefore, monitoring changes in nutrient hysteresis can provide a useful tool for detecting regime differences or changes within and between catchments. In the UK, the Demonstration Test Catchment (DTC) project has been set up to monitor evidence for improving water quality problems arising specifically from diffuse pollution from agriculture using targeted mitigation experiments and high resolution monitoring. This research platform provides an opportunity to compare storm-driven nutrient behaviour between catchments which have differing geologies, as well as how these behaviours evolve on a seasonal and annual basis. The monitoring to date has included a period of drought, directly followed by extreme wet conditions in the UK and therefore offers opportunities to assess the effect of differences in antecedent conditions on monitored nutrient response to rainfall events. The study compares the hysteretic behaviour of nutrients, including nitrogen and phosphorus species as well as sediment from a number of storm events of varying magnitudes throughout the 2011-2012 monitoring period in the Hampshire Avon catchment as part of the DTC programme. The investigation focuses

  12. Programmable Calculators and Minicomputers in Agriculture. A Symposium Exploring Computerized Decision-Making Aids and Their Extension to the Farm Level. Proceedings of a Symposium (Hot Springs, Arkansas, February 6-7, 1980)

    ERIC Educational Resources Information Center

    Bentley, Ernest, Ed.

    Ten papers presented at a symposium discuss the array of computerized decision-making aids currently available to farmers and ways to speed up the rate of adoption of computers by agriculturalists. Topics presented include the development of software for agricultural decision-making; the role of programmable calculators and minicomputers in…

  13. The influence of bedrock hydrogeology on catchment-scale nitrate fate and transport in fractured aquifers.

    PubMed

    Orr, Alison; Nitsche, Janka; Archbold, Marie; Deakin, Jenny; Ofterdinger, Ulrich; Flynn, Raymond

    2016-11-01

    Characterising catchment scale biogeochemical processes controlling nitrate fate in groundwater constitutes a fundamental consideration when applying programmes of measures to reduce risks posed by diffuse agricultural pollutants to water quality. Combining hydrochemical analyses with nitrate isotopic data and physical hydrogeological measurements permitted characterisation of biogeochemical processes influencing nitrogen fate and transport in the groundwater in two fractured bedrock aquifers with contrasting hydrogeology but comparable nutrient loads. Hydrochemical and isotopic analyses of groundwater samples collected from moderately fractured, diffusely karstified limestone indicated nitrification controlled dissolved nitrogen fate and delivery to aquatic receptors. By contrast nitrate concentrations in groundwater were considerably lower in a low transmissivity highly lithified sandstone and pyrite-bearing shale unit with patchy subsoil cover. Geophysical and hydrochemical investigations showed shallower intervals contained hydraulically active fractures where denitrification was reflected through lower nitrogen levels and an isotopic enrichment ratio of 1.7 between δ(15)N and δ(18)O. Study findings highlight the influence of bedrock hydrogeological conditions on aqueous nitrogen mobility. Investigation results demonstrate that bedrock conditions need to be considered when implementing catchment management plans to reduce the impact of agricultural practices on the quality of groundwater and baseflow in receiving rivers. Nitrate isotopic signatures in the groundwater of a freely draining catchment underlain by a karstified aquifer and a poorly draining aquifer with a low transmissivity aquifer. PMID:27432726

  14. New insight into pesticide partition coefficient Kd for modelling pesticide fluvial transport: application to an agricultural catchment in south-western France.

    PubMed

    Boithias, Laurie; Sauvage, Sabine; Merlina, Georges; Jean, Séverine; Probst, Jean-Luc; Sánchez Pérez, José Miguel

    2014-03-01

    Pesticides applied on crops are leached with rainfall to groundwater and surface water. They threat the aquatic environment and may render water unfit for human consumption. Pesticide partitioning is one of the pesticide fate processes in the environment that should be properly formalised in pesticide fate models. Based on the analysis of 7 pesticide molecules (alachlor, atrazine, atrazine's transformation product deethylatrazine or DEA, isoproturon, tebuconazole and trifluralin) sampled from July 2009 to October 2010 at the outlet of the river Save (south-western France), the objectives of this study were (1) to check which of the environmental factors (discharge, pH, concentrations of total suspended matter (TSM), dissolved organic carbon (DOC) and particulate organic carbon (POC) could control the pesticide sorption dynamic, and (2) to establish a relationship between environmental factors, the partition coefficient Kd and the octanol/water distribution coefficient Kow. The comparison of physico-chemical parameters values during low flow and high flow shows that discharge, TSM and POC are the factors most likely controlling the pesticide sorption processes in the Save river network, especially for lower values of TSM (below 13mgL(-1)). We therefore express Kd depending on the widely literature-related variable Kow and on the commonly simulated variable TSM concentration. The equation can be implemented in any model describing the fluvial transport and fate of pesticides in both dissolved and sorbed phases, thus, Kd becomes a variable in time and space. The Kd calculation method can be applied to a wide range of catchments and organic contaminants. PMID:24275149

  15. Assessing impact of climate and land use change on water quality in two contrasting meso-scale catchments in Poland

    NASA Astrophysics Data System (ADS)

    Marcinkowski, Pawel; Kardel, Ignacy; Ksiezniak, Marta; Berezowski, Tomasz; Okruszko, Tomasz; Mezghani, Abdelkader; Dobler, Andreas; Piniewski, Mikolaj

    2016-04-01

    The Upper Narew (4280 km2) and the Barycz (5520 km2) are two Polish, meso-scale, lowland catchments, contrasting in terms of land use, water management and water quality. Semi-distributed process-based SWAT model was applied in both catchments for assessment of climate change impact on selected water quality parameters. The model setup was developed based on high-resolution inputs, e.g. 5 km gridded precipitation and temperature dataset and 30 m Landsat8-based land cover map. Multi-site calibration and validation against observed discharge, sediment loads and nutrients loads (nitrogen and phosphorus compounds) gave predominantly satisfactory goodness-of-fit measures which enabled further model use for scenario analysis. Impact of land use on water quality can be assessed by comparing nutrients loads and concentrations simulated for the current conditions between two contrasting catchments. Both specific loads and concentrations of major nitrogen and phosphorous forms were on average 80-100% higher in the Barycz than in the Upper Narew catchment. This is a result of more intensive agricultural practices taking place in the Barycz, unlike the Upper Narew where agriculture is mostly extensive. Large parts of the Barycz catchment have been designed as the Nitrates Vulnerable Zones and since 2007 there are legal restrictions concerning agricultural practices in these areas. Nine GCM-RCM runs projected to the year 2100 for RCP 4.5 and 8.5 provided within the EURO-CORDEX experiment were first bias-corrected using quantile mapping method and then used as an ensemble of climate change scenarios in SWAT. Precipitation projections were largely consistent in showing an increasing precipitation trend, present particularly in winter and spring, in both catchments. This clearly affected the hydrological and biogeochemical cycle and resulted in higher projected water yield, increased erosion, and elevated nitrogen and phosphorus emission to water bodies. The rate of change caused

  16. Using high resolution water quality monitoring across three English catchments to capture a storm event during a transition from dry to wet conditions

    NASA Astrophysics Data System (ADS)

    Outram, F.; Lloyd, C.; Jonczyk, J.; Benskin, C.; Grant, F.

    2013-12-01

    The Demonstration Test Catchment (DTC) project is a UK government funded initiative to test the effectiveness of on-farm mitigation measures designed to reduce agricultural pollution without compromising farm productivity. Three distinct catchments in England have been chosen to test mitigation measures on working farms in small tributary catchments equipped with continuous water quality monitoring stations. The River Avon in the south is a chalk and sandstone catchment with livestock and arable farming, the River Wensum in the east is a lowland chalk catchment with predominantly arable farming and the River Eden in the North has a limestone and sandstone geology with predominantly livestock farming. One of the many strengths of the DTC as a national programme is that it provides the ability to investigate catchment hydrology and biogeochemical response across three different English landscapes. This is a collaborative paper involving members of all three DTC consortia, which aims to compare the responses of each of the catchments to a single storm event from April 2012, which was as a result of one of the first weather fronts to track across the country following a drought period affecting much of the UK, producing heavy rainfall in all three catchments. This was an unusual meteorological period, with subsequent hydrological implications when a rapid shift from drought to flood risk occurred across parts of the country. The effects of the weather front on discharge and water chemistry parameters, including N (NO3- and NH4), P (Total P (TP) and Total Reactive P (TRP)), dissolved oxygen (DO), chlorophyll and turbidity, measured at a half-hourly time step, are examined. When considered in the context of one hydrological year, flow and concentration duration curves reveal that the weather fronts resulted in extreme flow, nitrate and TP concentrations in all three catchments but with distinct differences in hydrograph and nutrient response. Hysteresis loops constructed

  17. Trapping runoff, sediment and nutrients at the edge-of-field: Using constructed wetlands to control runoff and improve water quality in agricultural catchments

    NASA Astrophysics Data System (ADS)

    Deasy, Clare; Quinton, John; Stoate, Chris

    2010-05-01

    Across Europe, many rivers and lakes are polluted. In the UK, the Biodiversity Action Plan estimates that over 70% of lakes are eutrophic. Diffuse pollution from agriculture is currently of extreme concern, but pollution and flood risk can be mitigated by management activities. The use of in-field mitigation options such as reduced tillage has been found to be effective at reducing runoff, sediment and nutrient loss in overland flow, but pollutants can still be lost from hillslopes unchecked via subsurface flow pathways, some of which may contribute very high loads of nutrients to streams. Edge-of-field mitigation approaches, which can tackle both surface and subsurface pathways at locations where they discharge into ditches and streams, therefore have greater potential as runoff control measures than in-field measures alone. In the UK, the implementation, effectiveness and functioning of seven new wetlands constructed at the edges of agricultural fields is currently being assessed. The constructed wetlands, of different designs, which are fed by different flow types and are located on different farm and soil types, are continuously monitored for discharge and turbidity at inlets and outlets, while storm sampling allows assessment of sediment and nutrient transfer into and out of the wetland at times when there is a high risk of pollutant transfer. Pond surveys and sediment sampling will take place annually, and tracer experiments will be carried out in the course of the project. The data will be used to generate information on sediment and nutrient load reductions or wetland effectiveness, wetland sediment and nutrient budgets, and water and sediment residence times. In this paper we present the initial results, including novel high-resolution data from the first monitored events. Early outputs suggest that constructed wetlands which receive surface runoff inputs can retain flood waters and may reduce flood peaks, wetlands built to take drain outfalls may be

  18. Phosphorus dynamics in lowland streams as a response to climatic, hydrological and agricultural land use gradients

    NASA Astrophysics Data System (ADS)

    Goyenola, G.; Meerhoff, M.; Teixeira-de Mello, F.; González-Bergonzoni, I.; Graeber, D.; Fosalba, C.; Vidal, N.; Mazzeo, N.; Ovesen, N. B.; Jeppesen, E.; Kronvang, B.

    2015-03-01

    Climate and hydrology are relevant control factors for determining the timing and amount of nutrient losses from agricultural fields to freshwaters. In this study, we evaluated the effect of agricultural intensification on the concentrations, dynamics and export of phosphorus (P) in streams in two contrasting climate and hydrological regimes (temperate Denmark and subtropical Uruguay). We applied two alternative nutrient sampling programmes (high frequency composite sampling and low frequency instantaneous-grab sampling) and three alternative methods to estimate exported P from the catchments. A source apportionment model was applied to evaluate the contribution derived from point and diffuse sources in all four catchments studied. Climatic and hydrological characteristics of catchments expressed as flow responsiveness (flashiness), exerted control on catchment and stream TP dynamics, having consequences that were more significant than the outcome of different TP monitoring and export estimation strategies. The impact of intensification of agriculture differed between the two contrasting climate zones. Intensification had a significant impact on subtropical climate with much higher total (as high as 4436 μg P L-1), particulate, dissolved and reactive soluble P concentrations and higher P export (as high as 5.20 kg P ha-1 year-1). However, we did not find an increased contribution of particulate P to total P as consequence of higher stream flashiness and intensification of agriculture. The high P concentrations at low flow and predominance of dissolved P in subtropical streams actually exacerbate the environmental and sanitary risks associated with eutrophication. In the other hand, temperate intensively farmed stream had lower TP than extensively farmed stream. Our results suggest that the lack of environmental regulations of agricultural production has more severe consequences on water quality, than climatic and hydrological differences between the analysed

  19. Catchment Restoration in the Tweed UNESCO-IHP HELP Basin - Eddleston Water

    NASA Astrophysics Data System (ADS)

    Spray, Christopher

    2013-04-01

    The EU Water Frame Work Directive (WFD) requires member states to work towards the achievement of 'good ecological status' for water bodies, through a 6 year cycle of river basin management plans (RBMPs). Within these RBMPs, states must develop and implement programmes of measures designed to improve the quality of individual water bodies at risk of failing to achieve this status. These RBMPS must not only be focussed on the key causes of failure, but increasingly look to deliver multiple benefits, such as flood risk reduction and improvement to biodiversity from such catchment interventions, and to involve communities and other stakeholders in restoration of their local environment. This paper reports on progress of a detailed study of the restoration of the Eddleston Water, a typical 'failing' water body in Scotland, the monitoring and governance arrangements behind this, and implications for rehabilitation of river systems elsewhere. Within UK rivers, the main causes of failure to achieve good ecological status are historical morphological changes to river courses, diffuse agricultural pollution and invasive non-native species. The Eddleston Water is a 70 sq kms sub-catchment of the Tweed, an UNESCO IHP-HELP basin in the Scottish : English borders, and is currently classified as 'bad' status, due largely to morphological changes to the course and structure of the river over the past 200 years. The main challenge therefor is physical restoration of the river to achieve functional connectivity with the flood plain. At the same time however, the two communities within the catchment suffer from flooding, so a second priority is to intervene within the catchment to reduce the risk of flooding through the use of "natural flood management" measures and, underlying both these two aspects a whole catchment approach to community participation and the achievement of a range of other ecosystem service benefits, including conservation of biodiversity. We report on the

  20. Nitrate concentrations and fluxes in the River Thames, London UK 1868 to 2008: catchment-scale modelling of diffuse agricultural sources and groundwater response using the world's longest water quality time series

    NASA Astrophysics Data System (ADS)

    Howden, N. J.; Burt, T. P.; Worrall, F.; Mathias, S.; Whelan, M.

    2011-12-01

    This paper presents analyses of the world's longest water quality record: 140 years of monthly-average nitrate concentrations (1868 to 2008) and fluxes (1883 to 2008) for the River Thames north of London. We show how short- and long- term patterns in these time series are influenced by both climatic and anthropogenic pressures, in the case of the latter, particularly land use and land management practices. Climate change does not play a significant role in controlling annual average concentrations or fluxes, rather large-scale land conversions from permanent grassland to arable farming have created sustained diffuse sources of nitrate that have caused (almost four-fold) increases in concentrations and fluxes that persist for many decades after the initial changes. Our analyses of this unique time series highlight four areas of particular interest: (1) Despite several layers of regulation and source control, fluvial concentrations and fluxes remain in- tractably high - no decrease has been observed since the early 1970s; (2) Catchment response to changing nitrogen inputs from land use and land management is subject to considerable lag: present conditions in the river reflect land practices from some years ago; (3) Following (2), we suggest that current changes to land use and land management practices will not be reflected in river water quality for some time to come; (4) Overall, the long-term view afforded by this record questions the derivation of "baseline conditions" that are formulated from records that do not reflect the massive changes in land use and land management in the mid-20th century. Overall, a better understanding of the links, and time delays, between cause (i.e. changing land use / land management) and fluvial response (i.e. concentration increase/decrease) will improve our ability both to predict changes in the coming decades, and inform management decision making now, to ensure the appropriate balance between agricultural development and

  1. Using high-resolution water quality monitoring to investigate hysteretic behaviour of nutrients at catchment scale

    NASA Astrophysics Data System (ADS)

    Lloyd, C.; Freer, J. E.; Johnes, P.; Collins, A.

    2013-12-01

    Changing climate and a growing population are increasing pressures on the world's water bodies. Maintaining food security has resulted in changes in agricultural practices, leading to adverse impacts on water quality. To address this problem robust evidence is needed to determine which on-farm mitigation strategies are likely to be most effective in reducing pollutant impacts. The introduction of in-situ quasi-continuous monitoring of water quality provides the means to improve the characterisation of pollutant behaviour and gain new understanding of hydrological and biogeochemical processes occurring within catchments. Here we use a suite of in-situ monitoring sensors to investigate changes in hysteretic patterns of nutrients in response to different environmental drivers. Observations of hysteretic behaviour can provide insights into the dominant transport pathways of pollutants. Therefore, monitoring changes in nutrient hysteresis can provide a useful tool for detecting catchment change. Such data also improves the quantification of pollutant loads and concentration dynamics. In the UK, the Demonstration Test Catchments (DTC) programme has been established to deliver evidence for improvements in water quality arising specifically from the deployment of measures to mitigate diffuse pollution from agriculture using high resolution in-situ monitoring. This research platform provides an opportunity to compare storm-driven nutrient behaviour between catchments which have differing geologies, and determine how these behaviours evolve on a seasonal and annual basis. The monitoring to date has included a period of drought in WY2011, directly followed by extreme wet conditions in the UK in WY2012 and therefore offers opportunities to assess the effect of differences in antecedent conditions on monitored nutrient response to rainfall events. The study compares the hysteretic behaviour of nutrients, including nitrogen and phosphorus species as well as turbidity from a

  2. Mechanisms for Enhancing Teachers' Effectiveness in the Implementation of Agricultural Science Programme in Secondary Schools in Afikpo Education Zone of Ebonyi State

    ERIC Educational Resources Information Center

    Ndem, Joseph Ukah

    2016-01-01

    Poor performance of students in agricultural science at the internal and external examinations has been attributed to ineffectiveness of the agricultural science teachers at the secondary schools in Afikpo education zone of Ebonyi State, therefore, this research determined the mechanisms for enhancing the teachers' effectiveness in the…

  3. Content of General Education in Programmes of Agricultural Technical and Vocational Institutions. Ukranian SSR. Studies in Technical and Vocational Education 26.

    ERIC Educational Resources Information Center

    Dorofeeva, N.; And Others

    Perhaps the main objective of vocational-technical education in the Ukrainian Soviet Socialist Republic today is to train middle-level managers and agricultural workers to take part in the republic's comprehensive program to accelerate its social and economic development. Secondary agricultural institutions called sovkhoz-technicums have played an…

  4. Nitrogen concentrations and losses from agricultural streams in the Nordic and Baltic countries

    NASA Astrophysics Data System (ADS)

    Stålnacke, Per; Bechmann, Marianne; Blicher-Mathiesen, Gitte; Iital, Arvo; Kyllmar, Katarina; Koskiaho, Jari; Lagzdins, Ainis; Povilaitis, Arvydas

    2015-04-01

    Assessment of long-term trends is one of the key objectives in most national water quality monitoring programmes. It is for example essential that we know how long it can take to detect the response in agricultural streams to changes in agriculture and implemented measures, because such information is needed to allow environmental authorities and decision and policy makers to establish realistic goals. Thus, long-term monitoring data is the key to cover future management needs and demands such as implementation of various EU-Directives (e.g., WFD, the Nitrates Directive). This paper in a uniform fashion examines the levels and temporal trends of nitrogen concentrations and losses in streams draining agricultural catchment areas in the Nordic and Baltic countries. 35 catchments (range 0.1-33km2) in Norway (9), Denmark (5), Sweden (8), Finland (4), Estonia (3), Latvia (3) and Lithuania (3) were selected for the study. Most of these catchments are part of national water quality monitoring programmes and initially selected to represent the major crops, soil types and climatic conditions in each country. The longest time series where 23 years (1988-2010) while the shortest one was 10 years (2002-2011). The reasons for these identified trends and no-trends will be discussed during the oral presentation in relation to land use, agricultural management and implementation of mitigation measures. Furthermore, the difference in mean level concentrations and losses will be discussed in relation to differences in climate, land use and agricultural management Overall the results show that agricultural catchments in the Nordic and Baltic countries exhibit different levels of nitrogen concentrations and losses, with a large interannual variability in all catchments. For example, the overall range in annual long-term mean TN losses was 6-102 kg N ha-1. Nearly one third of the investigated agricultural catchments showed statistically significant downward trends in nitrogen losses or

  5. Holocene sediments within lake catchments - testing sediment delivery

    NASA Astrophysics Data System (ADS)

    Dreibrodt, S.; Bork, H.-R.

    2009-04-01

    Results of detailed investigation of soils, colluvia and lake sediments in a lake catchment in northern Germany proves that the input of eroded soil (enabled by agricultural land use) is of a minor amount compared with the storage within colluvial layers. Pre-existing micro- and meso-topography and prehistorical land use patterns as well as precipitation intensity are probable to control the Holocene flux of sediments within the lake catchment area. Therefore we entertain some doubt if sediment delivery ratios- usually applied on larger spatial scales (e. g. river catchment areas)- are useful to produce reliable quantitative data of Holocene soil erosion in central Europe.

  6. Standardised survey method for identifying catchment risks to water quality.

    PubMed

    Baker, D L; Ferguson, C M; Chier, P; Warnecke, M; Watkinson, A

    2016-06-01

    This paper describes the development and application of a systematic methodology to identify and quantify risks in drinking water and recreational catchments. The methodology assesses microbial and chemical contaminants from both diffuse and point sources within a catchment using Escherichia coli, protozoan pathogens and chemicals (including fuel and pesticides) as index contaminants. Hazard source information is gathered by a defined sanitary survey process involving use of a software tool which groups hazards into six types: sewage infrastructure, on-site sewage systems, industrial, stormwater, agriculture and recreational sites. The survey estimates the likelihood of the site affecting catchment water quality, and the potential consequences, enabling the calculation of risk for individual sites. These risks are integrated to calculate a cumulative risk for each sub-catchment and the whole catchment. The cumulative risks process accounts for the proportion of potential input sources surveyed and for transfer of contaminants from upstream to downstream sub-catchments. The output risk matrices show the relative risk sources for each of the index contaminants, highlighting those with the greatest impact on water quality at a sub-catchment and catchment level. Verification of the sanitary survey assessments and prioritisation is achieved by comparison with water quality data and microbial source tracking. PMID:27280603

  7. Range-wide selection of catchments for Pacific salmon conservation.

    PubMed

    Pinsky, Malin L; Springmeyer, Dane B; Goslin, Matthew N; Augerot, Xanthippe

    2009-06-01

    Freshwater ecosystems are declining in quality globally, but a lack of data inhibits identification of areas valuable for conservation across national borders. We developed a biological measure of conservation value for six species of Pacific salmon (Oncorhynchus spp.) in catchments of the northern Pacific across Canada, China, Japan, Russia, and the United States. We based the measure on abundance and life-history richness and a model-based method that filled data gaps. Catchments with high conservation value ranged from California to northern Russia and included catchments in regions that are strongly affected by human development (e.g., Puget Sound). Catchments with high conservation value were less affected by agriculture and dams than other catchments, although only 1% were within biodiversity reserves. Our set of high-value areas was largely insensitive to simulated error, although classification remained uncertain for 3% of catchments. Although salmon face many threats, we propose they will be most likely to exhibit resilience into the future if a complementary mosaic of conservation strategies can be proactively adopted in catchments with healthy salmon populations. Our analysis provides an initial map of where these catchments are likely to be located. PMID:19220368

  8. How old is upland catchment water?

    NASA Astrophysics Data System (ADS)

    Hofmann, Harald; Cartwright, Ian; Morgenstern, Uwe; Gilfedder, Benjamin

    2014-05-01

    Understanding the dynamics of water supply catchments is an essential part of water management. Upland catchments provide a continuous, reliable source of high quality water not only for some of the world's biggest cities, but also for agriculture and industry. Headwater streams control river flow in lowland agricultural basins as the majority of river discharge emerges from upland catchments. Many rivers are perennial and flow throughout the year, even during droughts. However, it is still unclear how reliable and continuous upland catchment water resources really are. Despite many efforts in upland catchment research, there is still little known about where the water is stored and how long it takes to travel through upper catchments. Resolving these questions is crucial to ensure that this resource is protected from changing land use and to estimate potential impacts from a changing climate. Previous research in this important area has been limited by existing measurement techniques. Knowledge to date has relied heavily on the use of variation in stable isotope signals to estimate the age and origin of water from upland catchments. The problem with relying on these measures is that as the water residence time increases, the variation in the stable isotope signal decreases. After a maximum period of four years, no variation can be detected This means that to date, the residence time in upland catchments is likely to have been vastly underestimated. Consequently, the proportion of water flow out of upland river catchments to the total river flow is also underestimated. Tritium (3H) combines directly with water molecules and enters the flow paths with the infiltrating water. Its half-life (12.32 years) makes it ideal to describe residence times in upper catchment reservoirs as it can theoretically measure water up to about 150 years old. The bomb pulse peak in the southern hemisphere was several orders of magnitude lower than in the northern hemisphere. Hence the

  9. The anthropic catchment-ecosystem concept: an Irish example

    SciTech Connect

    Phillips-Howard, K.D.

    1985-06-01

    The catchment-ecosystem concept is adapted to investigate the nutrient-budget of the highly-modified Colebrooke drainage basin in Northern Ireland. Anthropogenic inputs, mainly manures and fertilizers, account for 86% of the nitrogen and 96% of the phosphorus added to the catchment. These inputs greatly exceed the streamflow outputs, thereby indicating that the flow of nutrients is dominated by agriculture. This is explained by the transformation of traditional mixed farming into more intensive livestock production and is linked to policies encouraging increased agricultural production, amalgamation of farms, afforestation, rural depopulation, and urbanization. Substantial increases in the N and P output of the catchment and further eutrophication of the recipient lake, Lough Erne, are predicted without the implementation of policies to reduce agricultural nutrient losses.

  10. Isotope methods as a tool to characterize nitrate origin and transport in Kocinka catchment (central Poland): preliminary results

    NASA Astrophysics Data System (ADS)

    Zurek, Anna; Wachniew, Przemyslaw; Witczak, Stanislaw; Rozanski, Kazimierz; Kania, Jaroslaw

    2014-05-01

    Kocinka catchment with 258 km2 of surface area is one of the Soils2Sea project (BONUS programme) case studies. One of the main scientific objectives of this project is to analyze how changes in land use and climate may affect the nutrient load to the Baltic Sea. Hydrogeological conditions in the Kocinka catchment are determined by Quaternary glacial till and glacifluvial sands and gravels underlain by karstic-fractured limestones which compose the Upper Jurassic Major Groundwater Basin (MGWB 326), one of four most important groundwater reservoirs in Poland. Pollution with nitrates is the most important threat to groundwater quality in this groundwater body. The concentration of nitrate in some wells, in the southern part of Kocinka catchment where outcrops of Jurassic limestones occur, exceeds the maximum permissible level of 50 mgNO3/L and constantly increases. A prerequisite for measures to reduce NO3 loads to the groundwater body is identification of sources of nitrate pollution. The working hypothesis links the high nitrate concentrations with the leaking sewage system in Czestochowa city and its surroundings but agricultural sources cannot be excluded as 66% of Kocinka catchment area is used agriculturally. A dedicated study employing environmental tracers was launched with the main aim of quantifying the pathways and dynamic of groundwater flow in the aquifer. Tritium was found throughout the system but its concentrations vary considerably. Decrease of tritium contents with depth in the aquifer was observed in one of wells. This points to active recharge and characteristic time scales of groundwater flow in order of years to several decades. To identify the origin of nitrate pollution nitrogen and oxygen isotope ratios of dissolved nitrate was analyzed in a number of wells with high nitrate concentrations. The isotopic composition of dissolved nitrates does not confirm the hypothesis on the decisive role of urban sewage in nitrate pollution. The isotope date

  11. Development of a New Zealand SedNet model for assessment of catchment-wide soil-conservation works

    NASA Astrophysics Data System (ADS)

    Dymond, John R.; Herzig, Alexander; Basher, Les; Betts, Harley D.; Marden, Mike; Phillips, Chris J.; Ausseil, Anne-Gaelle E.; Palmer, David J.; Clark, Maree; Roygard, Jon

    2016-03-01

    Much hill country in New Zealand has been converted from indigenous forest to pastoral agriculture, resulting in increased soil erosion. Following a severe storm that hit the Manawatu-Wanaganui region in 2004 and caused 62,000 landslides, the Horizons Regional Council have implemented the Sustainable Land Use Initiative (SLUI), a programme of widespread soil conservation. We have developed a New Zealand version (SedNetNZ) of the Australian SedNet model to evaluate the impact of the SLUI programme in the 5850 km2 Manawatu catchment. SedNetNZ spatially distributes budgets of fine sediment in the landscape. It incorporates landslide, gully, earthflow erosion, surficial erosion, bank erosion, and flood-plain deposition, the important forms of soil erosion in New Zealand. Modelled suspended sediment loads compared well with measured suspended sediment loads with an R2 value of 0.85 after log transformation. A sensitivity analysis gave the uncertainty of estimated suspended sediment loads to be approximately plus or minus 50% (at the 95% confidence level). It is expected that by 2040, suspended sediment loads in targeted water management zones will decrease by about 40%. The expected decrease for the whole catchment is 34%. The expected reduction is due to maturity of tree planting on land at risk to soil erosion. The 34% reduction represents an annual rate of return of 20% on 20 million NZ of investment on soil conservation works through avoided damage to property and infrastructure and avoided clean-up costs.

  12. Leaf breakdown in streams differing in catchment land use

    USGS Publications Warehouse

    Paul, M.J.; Meyer, J.L.; Couch, C.A.

    2006-01-01

    1. The impact of changes in land use on stream ecosystem function is poorly understood. We studied leaf breakdown, a fundamental process of stream ecosystems, in streams that represent a range of catchment land use in the Piedmont physiographic province of the south-eastern United States. 2. We placed bags of chalk maple (Acer barbatum) leaves in similar-sized streams in 12 catchments of differing dominant land use: four forested, three agricultural, two suburban and three urban catchments. We measured leaf mass, invertebrate abundance and fungal biomass in leaf bags over time. 3. Leaves decayed significantly faster in agricultural (0.0465 day-1) and urban (0.0474 day-1) streams than in suburban (0.0173 day-1) and forested (0.0100 day-1) streams. Additionally, breakdown rates in the agricultural and urban streams were among the fastest reported for deciduous leaves in any stream. Nutrient concentrations in agricultural streams were significantly higher than in any other land-use type. Fungal biomass associated with leaves was significantly lower in urban streams; while shredder abundance in leaf bags was significantly higher in forested and agricultural streams than in suburban and urban streams. Storm runoff was significantly higher in urban and suburban catchments that had higher impervious surface cover than forested or agricultural catchments. 4. We propose that processes accelerating leaf breakdown in agricultural and urban streams were not the same: faster breakdown in agricultural streams was due to increased biological activity as a result of nutrient enrichment, whereas faster breakdown in urban streams was a result of physical fragmentation resulting from higher storm runoff. ?? 2006 The Authors.

  13. Catchment management and the Great Barrier Reef.

    PubMed

    Brodie, J; Christie, C; Devlin, M; Haynes, D; Morris, S; Ramsay, M; Waterhouse, J; Yorkston, H

    2001-01-01

    Pollution of coastal regions of the Great Barrier Reef is dominated by runoff from the adjacent catchment. Catchment land-use is dominated by beef grazing and cropping, largely sugarcane cultivation, with relatively minor urban development. Runoff of sediment, nutrients and pesticides is increasing and for nitrogen is now four times the natural amount discharged 150 years ago. Significant effects and potential threats are now evident on inshore reefs, seagrasses and marine animals. There is no effective legislation or processes in place to manage agricultural pollution. The Great Barrier Reef Marine Park Act does not provide effective jurisdiction on the catchment. Queensland legislation relies on voluntary codes and there is no assessment of the effectiveness of the codes. Integrated catchment management strategies, also voluntary, provide some positive outcomes but are of limited success. Pollutant loads are predicted to continue to increase and it is unlikely that current management regimes will prevent this. New mechanisms to prevent continued degradation of inshore ecosystems of the Great Barrier Reef World Heritage Area are urgently needed. PMID:11419129

  14. Investigating dominant processes on small poorly gauged catchments: an inter-comparison approach for catchment similarity study

    NASA Astrophysics Data System (ADS)

    Crabit, Armand; Colin, François; Moussa, Roger; Lagacherie, Philippe

    2010-05-01

    Small catchment scales appear to be relevant to study and manage agricultural uses and their hydrological impacts. Mediterranean small catchment responses are characterised by short duration surface runoff due to intense rainfall events of short duration. Ephemeral streams are common fluvial systems: they are usually dry for most of the year and become particularly active during flood events. This considerably complicates hydrological analysis. Therefore, estimating and predicting runoff for small ungauged (or poorly gauged) catchments appears to be a significant challenge. It would allow to a better understanding of dominant processes in relation with catchment functions (partition, release, storage). According to many authors, classification and similarity concepts, which can be profitably used when the processes are not fully understood, could be conducted as an alternative to complex modelling. This study proposes a new methodology for small poorly gauged catchments to (i) estimate surface runoff and associated uncertainty and (ii) identify dominant functions governing hydrological responses. The work focuses on twelve small agricultural catchments, within the French Mediterranean region, with areas ranging between 0,3 and 1 km2. Water depth at the catchment's outlet and rainfall intensities have been collected at a one-minute data step, from September 2008 to September 2009. The analysis has been conducted on 120 flood events. The first step was to make an inter-catchment comparison based on limited hydrological data considering the associated uncertainty. Estimation of flow velocity for natural ephemeral channel is a difficult task. To assess catchment runoff, flow rate curves were established from water depth using Manning's equation. Innovative field and laboratory experiments have been carried out to estimate Manning's coefficient for typical Mediterranean non-aquatic vegetation types. 72 tests have been realised to analyse the effects of vegetation

  15. Human-Landscape interaction in cultivated lowland catchments (Louroux catchment, Loire Valley, France)

    NASA Astrophysics Data System (ADS)

    Cerdan, Olivier; Foucher, Anthony; Gay, Aurore; Salvador Blanes, Sébastien; Evrard, Olivier; Desmet, Marc

    2015-04-01

    Change of land use or agricultural practices are known to have high impacts on sediment transfer in catchments and rivers. Numerous studies have particularly illustrated these effects in sloping land in tropical areas undergoing deforestation. Much less attention has been paid to lowland humid areas, where permanent land uses have been plowed more recently. However recent studies reported significant erosion rates in these environments despite the gentle topography and the temperate climate. In order to quantify these changing fluxes of sediment, several instrumentation and historical database analyses were carried out in various catchments of the Loire Valley, France. More particularly, a multiparameter analysis was conducted on sedimentary deposits of a pond created in the 11th century in a catchment representative of cultivated and drained lowland environments where an intensification of agricultural practices has occurred during the last 60 years. The results showed that the initial land consolidation period (1954-1960) was characterized by a dominance of allochtonous material input to the pond. This input represents an erosion of 1900 to 2300 t.km-².yr-1 originating from the catchment. Then, between 1970-1990, terrigenous material flow decreased progressively and tended to stabilize, whereas eutrophication and associated primary production increased in the pond. In addition to these temporal changes, material input across the pond during the last 10 years corresponds to a loss of material in the catchment ranging between 90 and 102 t.km-2.yr-1. While a strong decrease is observed, it still represents a 60-fold increase of the sediment fluxes to the pond compared to the preintensification period. Subsequent research monitoring studies permitted to differentiate between the different sources of sediment and highlight the importance of surface erosion during flood events and of bank erosion during low flows. The increased export of the sediment is primarily due

  16. Accelerated export of sediment and carbon from a landscape under intensive agriculture.

    PubMed

    Glendell, M; Brazier, R E

    2014-04-01

    The export of total organic carbon (particulate and dissolved) from terrestrial to aquatic ecosystems has important implications for water quality and the global carbon cycle. However, most research to date has focused on DOC losses from either forested or peaty catchments, with only limited studies examining the controls and rates of total fluvial carbon losses from agricultural catchments, particularly during storm events. This study examined the controls and fluxes of total suspended sediment (SS), total particulate (TPC) and dissolved organic carbon (DOC) from two adjacent catchments with contrasting intensive agricultural and semi-natural land-use. Data from 35 individual storm events showed that the agricultural catchment exported significantly higher SS concentrations on a storm-by-storm basis than the semi-natural catchment, with peak discharge exerting a greater control over SS, TPC and DOC concentrations. Baseflow DOC concentrations in the agricultural catchment were significantly higher. DOC quality monitored during one simultaneous rainfall event differed between the two study catchments, with more humic, higher molecular weight compounds prevailing in the agricultural catchment and lower molecular weight compounds prevailing in the semi-natural catchment. During an eight month period for which a comparable continuous turbidity record was available, the estimated SS yields from the agricultural catchment were higher than from the semi-natural catchment. Further, the agricultural catchment exported proportionally more TPC and a comparable amount of DOC, despite a lower total soil carbon pool. These results suggest that altered hydrological and biogeochemical processes within the agricultural catchment, including accelerated soil erosion and soil organic matter turnover, contributed to an enhanced fluvial SS and carbon export. Thus, we argue that enhancing semi-natural vegetation within intensively farmed catchments could reduce sediment and carbon losses

  17. Multiple-method approaches for quantifying fine sediment dynamics in river catchments over contemporary timescales

    NASA Astrophysics Data System (ADS)

    Smith, Hugh

    2015-04-01

    Understanding the patterns and processes of contemporary fine sediment dynamics in river catchments constitutes a key research challenge for catchment scientists. Such knowledge has considerable value for the targeting of management resources to reduce excess fine sediment supply and its impacts on water resources and aquatic ecosystems. Many past studies tended to focus on a single compartment of the fine sediment cascade and utilised a limited range of research methods. For more holistic understanding, the use of multiple-method approaches is required to provide data on the sources, transfer, storage, and transit times of fine sediment in river catchments. Such approaches would allow scientists to better conceptualise catchment processes controlling the movement of fine sediment across a range of spatial scales. It may also enhance the scientific quality of catchment-scale studies through the acquisition of multiple lines of evidence concerning a particular research problem. The specific combination of fine sediment tracing and fingerprinting procedures with catchment sediment flux measurements and sediment budget modelling has considerable potential to enhance our knowledge of contemporary sediment dynamics. This combination of techniques offers complementary information and the opportunity to compare datasets, such as estimates of catchment sediment source contributions obtained using sediment tracers with direct measurements of sediment fluxes or catchment model outputs. This contribution explores the potential for such combinations of methods to yield distinctive insights not otherwise available from the use of only one of these techniques. It draws on published examples of multiple-method studies by the author from small agricultural and wildfire-affected forest catchments (1-2 km2) in south-east Australia and from larger agricultural river catchments (38-920 km2) in south-west England. It will also identify possible directions for catchment research based

  18. The application of GEOtop for catchment scale hydrology in Ireland

    NASA Astrophysics Data System (ADS)

    Lewis, C.; Xu, X.; Albertson, J.; Kiely, G.

    2009-04-01

    GEOtop represents the new generation of distributed hydrological model driven by geospatial data (e.g. topography, soils, vegetation, land cover). It estimates rainfall-runoff, evapotranspiration and provides spatially distributed outputs as well as routing water and sediment flows through stream and river networks. The original version of GEOtop designed in Italy, includes a rigorous treatment of the core hydrological processes (e.g. unsaturated and saturated flow and transport, surface energy balances, and streamflow generation/routing). Recently GEOtop was extended to include treatment of shallow landslides. The GEOtop model is built on an open-source programming framework, which makes it well suited for adaptation and extension. GEOtop has been run very successfully in a number of alpine catchments (such as Brenta) but has not been used on Irish catchments before. The cell size used for the spatially distributed inputs varies from catchment to catchment. In smaller catchments (less than 2000ha) 50 by 50m cells have been used and 200 by 200 for larger catchments. Smaller cell sizes have been found to significantly increase the computational time so a larger cell size is used providing it does not significantly affect the performance of the model. Digital elevation model, drainage direction, landuse and soil type maps are the minimum spatial requirements with precipitation, radiation, temperature, atmospheric pressure and wind speed been the minimum meteorological requirements for a successful run. The soil type maps must also contain information regarding texture and hydraulic conductivity. The first trial of GEOtop in Ireland was on a small 1524 ha catchment in the south of Ireland. The catchment ranges from 50 to just over 200m, the land use is predominately agricultural grassland and it receives on average 1400mm of rain per year. Within this catchment there is a meteorological tower which provides the meteorological inputs, soil moisture is also recorded at

  19. Modularised process-based modelling of phosphorus loss at farm and catchment scale

    NASA Astrophysics Data System (ADS)

    Hutchins, M. G.; Anthony, S. G.; Hodgkinson, R. A.; Withers, P. J. A.

    In recent years, a co-ordinated programme of data collection has resulted in the collation of sub-hourly time-series of hydrological, sediment and phosphorus loss data, together with soil analysis, cropping and management information for two small (< 200 ha) headwater agricultural catchments in the UK Midlands (Rosemaund, Herefordshire and Cliftonthorpe, Leicestershire). These data sets have allowed the dynamics of phosphorus loss to be characterised and the importance of both storm runoff and drainflow to be identified, together with incidental losses following manure and fertiliser additions in contributing to total annual loss. A modularised process-based model has been developed to represent current understanding of the dynamics of phosphorus loss. Modules describing runoff and sediment generation and associated phosphorus adsorption/desorption dynamics are described and tested. In the model, the effect of a growing crop on sediment detachment processes is represented and the stability of topsoil is considered so that, overall, the model is responsive to farm management factors. Importantly, using data sets available from national-scale survey programmes to estimate model parameters, a transferable approach is presented, requiring only sub-hourly rainfall data and field-specific landcover information for application of the model to new sites. Results from application of the model to the hydrological year 1998-99 are presented. Assessment of performance, which suggests that the timing of simulated responses is acceptable, has focused attention on quantifying landscape and in-stream retention and remobilisation processes.

  20. Modeling relationships between catchment attributes and river water quality in southern catchments of the Caspian Sea.

    PubMed

    Hasani Sangani, Mohammad; Jabbarian Amiri, Bahman; Alizadeh Shabani, Afshin; Sakieh, Yousef; Ashrafi, Sohrab

    2015-04-01

    Increasing land utilization through diverse forms of human activities, such as agriculture, forestry, urban growth, and industrial development, has led to negative impacts on the water quality of rivers. To find out how catchment attributes, such as land use, hydrologic soil groups, and lithology, can affect water quality variables (Ca(2+), Mg(2+), Na(+), Cl(-), HCO 3 (-) , pH, TDS, EC, SAR), a spatio-statistical approach was applied to 23 catchments in southern basins of the Caspian Sea. All input data layers (digital maps of land use, soil, and lithology) were prepared using geographic information system (GIS) and spatial analysis. Relationships between water quality variables and catchment attributes were then examined by Spearman rank correlation tests and multiple linear regression. Stepwise approach-based multiple linear regressions were developed to examine the relationship between catchment attributes and water quality variables. The areas (%) of marl, tuff, or diorite, as well as those of good-quality rangeland and bare land had negative effects on all water quality variables, while those of basalt, forest land cover were found to contribute to improved river water quality. Moreover, lithological variables showed the greatest most potential for predicting the mean concentration values of water quality variables, and noting that measure of EC and TDS have inversely associated with area (%) of urban land use. PMID:25395322

  1. A methodological comparison of catchment storages in mountainous catchments

    NASA Astrophysics Data System (ADS)

    Weiler, Markus; Staudinger, Maria; Stölzle, Michael; Seeger, Stefan; Seibert, Jan; Stahl, Kerstin

    2015-04-01

    One of the most important functions of catchments is the temporary storage of water, which directly influences runoff dynamics, rainfall-runoff transformation, partitioning of evaporation and runoff fluxes, and accessibility of water to plants. Generally, a large catchment storage is considered beneficial and in particular increases the transit times and hence the buffer functioning related to water quality. Many different methods have been developed to assess catchment storage, however, there are hardly any direct comparisons of several of these methods. One challenge is the definition of water storage, while some methods allow estimation of the entire water storage in a catchment, other methods quantify only the dynamic storage. In addition, most studies focused more on lowland catchments with rain-dominated runoff regimes and observed groundwater fluctuations. Furthermore, these studies often focus on one or two catchments, but do not consider the influence of different climates on the relevance of water storage in the catchment. We applied a range of different methods to assess catchment storage characteristics in 18 catchments in the Swiss Alps, ranging from 500 to 2000m of mean elevation and hence from rainfall- to snowmelt dominated runoff regimes. The first method use only discharge information during recession periods and with varying approaches to extract discharge and storage changes between high flow and low flow, the dynamic catchment storage can be derived. In the next methods the conceptual hydrological model HBV is calibrated to the runoff dynamics and the dynamic and total catchment storages of the different compartments are being evaluated. The last methods are based on stable water isotope data analysis. We use the model TRANSEP to derive the dynamic storage as well as the total water storage of the catchment based on the transit times using several years of fortnightly isotope data in streamflow. The results show that the derived catchment

  2. Water Catchment and Storage Monitoring

    NASA Astrophysics Data System (ADS)

    Bruenig, Michael; Dunbabin, Matt; Moore, Darren

    2010-05-01

    Sensors and Sensor Networks technologies provide the means for comprehensive understanding of natural processes in the environment by radically increasing the availability of empirical data about the natural world. This step change is achieved through a dramatic reduction in the cost of data acquisition and many orders of magnitude increase in the spatial and temporal granularity of measurements. Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) is undertaking a strategic research program developing wireless sensor network technology for environmental monitoring. As part of this research initiative, we are engaging with government agencies to densely monitor water catchments and storages, thereby enhancing understanding of the environmental processes that affect water quality. In the Gold Coast hinterland in Queensland, Australia, we are building sensor networks to monitor restoration of rainforest within the catchment, and to monitor methane flux release and water quality in the water storages. This poster will present our ongoing work in this region of eastern Australia. The Springbrook plateau in the Gold Coast hinterland lies within a World Heritage listed area, has uniquely high rainfall, hosts a wide range of environmental gradients, and forms part of the catchment for Gold Coast's water storages. Parts of the plateau are being restored from agricultural grassland to native rainforest vegetation. Since April 2008, we have had a 10-node, multi-hop sensor network deployed there to monitor microclimate variables. This network will be expanded to 50-nodes in February 2010, and to around 200-nodes and 1000 sensors by mid-2011, spread over an area of approximately 0.8 square kilometers. The extremely dense microclimate sensing will enhance knowledge of the environmental factors that enhance or inhibit the regeneration of native rainforest. The final network will also include nodes with acoustic and image sensing capability for

  3. Assessing factorial and convergent validity and reliability of a food behaviour checklist for Spanish-speaking participants in US Department of Agriculture nutrition education programmes

    PubMed Central

    Banna, Jinan C; Townsend, Marilyn S

    2015-01-01

    Objective To assess convergent validity, factorial validity, test–retest reliability and internal consistency of a diet quality food behaviour checklist (FBC) for low-literate, low-income Spanish speakers. Design Participants (n 90) completed three dietary recalls, the Spanish-language version of the US Department of Agriculture (USDA) Household Food Security Survey Module (HFSSM) and the Spanish-language FBC. Factor structure was examined using principal component analysis. Spearman correlation coefficients between FBC item responses and nutrient intakes from 24 h recalls were used to estimate convergent validity. Correlation coefficients were also calculated between FBC item responses at two time points in another group of participants (n 71) to examine test–retest reliability. Cronbach's α coefficient was determined for items within each sub-scale. Setting Non-profit community agencies serving low-income clients, migrant farm worker camps and low-income housing sites in four California counties. Subjects Spanish-speaking women (n 161) who met income eligibility for the SNAP-Ed (Supplemental Nutrition Assistance Program–Education). Results Factor analysis resulted in six sub-scales. Responses to nineteen food behaviour items were significantly correlated with hypothesized 24 h recall data (with a maximum correlation of 0·44 for drinking milk and calcium) or the USDA HFSSM (0·42 with the food security item). Coefficients for test–retest reliability ranged from 0·35 to 0·79. Cronbach's α ranged from 0·49 for the diet quality sub-scale to 0·80 for the fruit and vegetable sub-scale. Conclusions The twenty-two-item FBC and instruction guide will be used to evaluate USDA community nutrition education interventions with low-literate Spanish speakers. This research contributes to the body of knowledge about this at-risk population in California. PMID:21338552

  4. Kresoxim methyl deposition, drift and runoff in a vineyard catchment.

    PubMed

    Lefrancq, M; Imfeld, G; Payraudeau, S; Millet, M

    2013-01-01

    Surface runoff and spray drift represent a primary mode of pesticide mobilisation from agricultural land to ecosystem. Though pesticide drift has mainly been studied at small scale (<1 ha), pesticide transports by drift and runoff have rarely been compared in the same agricultural catchment. Here kresoxim methyl (KM) drift during foliar application was evaluated in a vineyard catchment (Rouffach, Alsace, France), and KM deposition on non-target surfaces was compared to KM runoff. KM was detected on 55% of the collectors and concentration reached 18% of the applied dose (i.e. 1.5 mg m(-2)). Our results indicated that KM soil deposition greatly varied in space and time. The total KM soil deposition in the vineyard plots was estimated by four different interpolation methods (arithmetic mean, Thiessen method, inverse weighting distance and ordinary kriging) and ranged between 53 g and 61 g (5.8 and 6.6% of the total mass applied). The amount of KM drifted on roads was 50 times larger than that in runoff water collected at the outlet of the catchment. Although KM application was carried out under regular operational and climatic conditions, its deposition on non-target surfaces may be significant and lead to pesticide runoff. These results can be anticipated as a starting point for assessing pesticide deposition during spray application and corresponding pesticide runoff in agricultural catchments. PMID:23201604

  5. Moments of catchment storm area

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.; Wang, Q.

    1985-01-01

    The portion of a catchment covered by a stationary rainstorm is modeled by the common area of two overlapping circles. Given that rain occurs within the catchment and conditioned by fixed storm and catchment sizes, the first two moments of the distribution of the common area are derived from purely geometrical considerations. The variance of the wetted fraction is shown to peak when the catchment size is equal to the size of the predominant storm. The conditioning on storm size is removed by assuming a probability distribution based upon the observed fractal behavior of cloud and rainstorm areas.

  6. Regional nitrogen dynamics in the TERENO Bode River catchment, Germany, as constrained by stable isotope patterns.

    PubMed

    Mueller, Christin; Krieg, Ronald; Merz, Ralf; Knöller, Kay

    2016-01-01

    Interactions between hydrological characteristics and microbial activities affect the isotopic composition of dissolved nitrate in surface water. Nitrogen and oxygen isotopic signatures of riverine nitrate in 133 sampling locations distributed over the Bode River catchment in the Harz Mountains, Germany, were used to identify nitrate sources and transformation processes. An annual monitoring programme consisting of seasonal sampling campaigns in spring, summer and autumn was conducted. δ(15)N and δ(18)O of nitrate and corresponding concentrations were measured as well as δ(2)H and δ(18)O of water to determine the deuterium excess. In addition, precipitation on 25 sampling stations was sampled and considered as a potential input factor. The Bode River catchment is strongly influenced by agricultural land use which is about 70 % of the overall size of the catchment. Different nitrogen sources such as ammonia (NH4) fertilizer, soil nitrogen, organic fertilizer or nitrate in precipitation show partly clear nitrate isotopic differences. Processes such as microbial denitrification result in fractionation and lead to an increase in δ(15)N of nitrate. We observed an evident regional and partly temporal variation of nitrate isotope signatures which are clearly different between main landscape types. Spring water sections within the high mountains contain nitrate in low concentrations with low δ(15)NNO3 values of -3 ‰ and high δ(18)ONO3 values up to 13 ‰. High mountain stream water sub-catchments dominated by nearly undisturbed forest and grassland contribute nitrate with δ(15)NNO3 and δ(18)ONO3 values of -1 and -3.5 ‰, respectively. In the further flow path, which is affected by an increasing agricultural land use and urban sewage, we recognized an increase in δ(15)NNO3 and δ(18)ONO3 up to 22 and 18 ‰, respectively, with high variations during the year. A correlation seems to exist between the percentage of agricultural land use area and the

  7. Hydrological Catchment Similarity Assessment in Geum River Catchments, Korea

    NASA Astrophysics Data System (ADS)

    Ko, Ara; Park, Kisoon; Lee, Hyosang

    2013-04-01

    Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is notclearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum river catchments, Korea. Three Catchment Characteristics, Area (A)-Annual precipitation (SAAR)-SCS Curve Number (CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve (ILow:Q275/Q185, IDrought:Q355/Q185, IFlood:Qmax/Q185, IAbundant:Q95/Q185, IFloodDuration:Q10/Q355 and IRiverRegime:Qmax/Qmin) are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups: H1 (Cheongseong, Gidae, Bukil, Oksan, Seockhwa, Habgang and Sangyeogyo), H2 (Cheongju, Guryong, Ugon, Boksu, Useong and Seokdong) and H3 (Muju, Yangganggyo and YongdamDam). The four catchments (Cheoncheon, Donghyang, DaecheongDam and Indong) are not grouped in this study. The clustering analysis of FDC provides four Groups; CFDC1 (Muju, YongdamDam, Yangganggyo, DaecheongDam, Cheongseong, Gidae, Seokhwa, Bukil, Habgang, Cheongju, Oksan, Yuseong and Guryong), CFDC2 (Cheoncheon, Donghyang, Boksu, Indong, Nonsan, Seokdong, Ugon, Simcheon, Useong and Sangyeogyo), CFDC3 (Songcheon) and CFDC4 (Tanbu). The six catchments (out of seven) of H1 are grouped in CFDC1, while Sangyeogyo is grouped in CFDC2. The four catchments (out of six) of H2 are also grouped in CFDC2, while Cheongju and Guryong are grouped in CFDC1. The catchments of H3 are categorized in CFDC1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (CFDC1 and CFDC2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by

  8. Carbon redistribution by erosion processes in an intensively disturbed catchment

    NASA Astrophysics Data System (ADS)

    Boix-Fayos, Carolina; Martínez-Mena, María; Pérez Cutillas, Pedro; de Vente, Joris; Barberá, Gonzalo G.; Mosch, Wouter; Navarro Cano, Jose Antonio; Gaspar, Leticia; Navas, Ana

    2016-04-01

    Understanding how organic carbon moves with sediments along the fluvial system is crucial to close catchment scale carbon budgets. Especially challenging is the analysis of organic carbon dynamics during fluvial transport in heterogeneous, fragile and disturbed environments with ephemeral and intense hydrological pulses, typical of Mediterranean conditions. This paper explores the catchment scale organic carbon redistribution by lateral flows in extreme Mediterranean environmental conditions from a geomorphological perspective. The study area is a catchment (Cárcavo) in SE Spain with a semiarid climate, erodible lithologies, shallow soils, and highly disturbed by agricultural terraces, land levelling, reforestations and construction of check-dams. To increase understanding of erosion induced catchment scale organic carbon redistribution, we studied the subcatchments of 8 check-dams distributed along the catchment main channel in detail. We determined 137Cs, physicochemical characteristics and organic carbon pools of soils and sediments deposited behind each check-dam, performed spatial analysis of properties of the catchment and buffer areas around check-dams, and carried out geomorphological analysis of the slope-channel connections. Soils showed very low Total Organic Carbon (TOC) values oscillating between 15.2 and 4.4 g Kg-1 for forest and agricultural soils, respectively. Sediments mobilized by erosion were poor in TOC compared to the eroded (forest) soils (6.6±0.7 g Kg-1), and the redistribution of organic carbon through the catchment, especially of the Mineral Associated Organic Carbon (MAC) pool, showed the same pattern as clay particles and 137Cs. The TOC erosion rates (0.031±0.03 Mg ha-1 y-1) were comparable to others reported for subhumid Mediterranean catchments and to those modelled worldwide for pasture land. Those lateral fluxes were equivalent to 10.4 % of the TOC stock from the topsoil at the moment of the check-dam construction and

  9. Guiding soil conservation strategy in headwater mediterranean catchments

    NASA Astrophysics Data System (ADS)

    Ben Slimane, Abir; Raclot, Damien; Evrard, Olivier; Sanaa, Mustapha; Lefèvre, Irène; Le Bissonnais, Yves

    2016-04-01

    Reservoir siltation due to water erosion is an important environmental issue in Mediterranean countries where storage of clear surface water is crucial for their economic and agricultural development. In order to reduce water erosion, this study aimed to design a methodology for guiding the implementation of efficient conservation strategies by identifying the dominant sediment sources in Mediterranean context. To this end, a fingerprinting method was combined with long-term field monitoring of catchment sediment yield in five headwater catchments (0.1-10 km2) equipped with a small reservoir between 1990 and 1995. The five catchments were chosen to cover the large diversity of environmental conditions found along the Tunisian Ridge and in the Cape Bon region. The fingerprinting techniques based on measurements of cesium-137 and Total Organic Carbon within the catchments and in reservoir sediment deposits successfully identified the contribution of rill/interrill and gully/channel erosion to sediment yield at the outlet of five small headwater catchments during the last 15-20 years. Results showed the very large variability of erosion processes among the selected catchments, with rill/interrill erosion contributions to sediment accumulated in outlet reservoirs ranging from 20 to 80%. Overall, rill/interrill erosion was the dominant process controlling reservoir siltation in three catchments whereas gully/channel erosion dominated in the other two catchments. This demonstrates that the dominant erosion process in the Mediterranean regions highly depends on the local environmental context. The lowest rill/interrill erosion contribution (2.2 Mg ha-1 yr-1) in the five catchments remained significantly higher than the tolerable soil loss indicating the severe levels reached by soil erosion along the Tunisian Ridge and in the Cape Bon region. This study also showed that although the implementation of improved topsoil management measures greatly reduced rill

  10. Programmable Pulser

    NASA Technical Reports Server (NTRS)

    Baumann, Eric; Merolla, Anthony

    1988-01-01

    User controls number of clock pulses to prevent burnout. New digital programmable pulser circuit in three formats; freely running, counted, and single pulse. Operates at frequencies up to 5 MHz, with no special consideration given to layout of components or to terminations. Pulser based on sequential circuit with four states and binary counter with appropriate decoding logic. Number of programmable pulses increased beyond 127 by addition of another counter and decoding logic. For very large pulse counts and/or very high frequencies, use synchronous counters to avoid errors caused by propagation delays. Invaluable tool for initial verification or diagnosis of digital or digitally controlled circuity.

  11. Programmable Pacemaker

    NASA Technical Reports Server (NTRS)

    1980-01-01

    St. Jude Medical's Cardiac Rhythm Management Division, formerly known as Pacesetter Systems, Inc., incorporated Apollo technology into the development of the programmable pacemaker system. This consists of the implantable pacemaker together with a physician's console containing the programmer and a data printer. Physician can communicate with patient's pacemaker by means of wireless telemetry signals transmitted through the communicating head held over the patient's chest. Where earlier pacemakers deliver a fixed type of stimulus once implanted, Programalith enables surgery free "fine tuning" of device to best suit the patient's changing needs.

  12. Changes in catchment hydrology in relation to vegetation recovery: a comparative modelling experiment

    NASA Astrophysics Data System (ADS)

    Lana-Renault, Noemí; Karssenberg, Derek; Latron, Jérôme; Serrano, Mā Pilar; Regüés, David; Bierkens, Marc F. P.

    2010-05-01

    Mediterranean mountains have been largely affected by land abandonment and subsequent vegetation recovery, with a general expansion of shrubs and forests. Such a large scale land-cover change has modified the hydrological behavior of these areas, with significant impact on runoff production. Forecasting the trend of water resources under future re-vegetation scenarios is of paramount importance in Mediterranean basins, where water management relies on runoff generated in these areas. With this purpose, a modelling experiment was designed based on the information collected in two neighbouring research catchments with a different history of land use in the central Spanish Pyrenees. One (2.84 km2) is an abandoned agricultural catchment subjected to plant colonization and at present mainly covered by shrubs. The other (0.92 km2) is a catchment covered by dense natural forest, representative of undisturbed environments. Here we present the results of the analysis of the hydrological differences between the two catchments, and a description of the approach and results of the modelling experiment. In a statistical analysis of the field data, significant differences were observed in the streamflow response of the two catchments. The forested catchment recorded fewer floods per year compared to the old agricultural catchment, and its hydrological response was characterised by a marked seasonality, with autumn and spring as the only high flow periods. Stormflow was generally higher in the old agricultural catchment, especially for low to intermediate size events; only for large events the stormflow in the forested catchment was sometimes greater. Under drier conditions, the relative differences in the stormflow between the two catchments tended to increase whereas under wet conditions they tended to be similar. The forested catchment always reacted more slowly to rainfall, with lower peakflows (generally one order of magnitude lower) and longer recession limbs. The modelling

  13. Characterizing Runoff and Water Yield from Headwater Catchments in the Southern Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Safeeq, M.; Hunsaker, C. T.

    2015-12-01

    In a mediterranean climate where much of the annual precipitation falls during winter, the snow-capped Sierra Nevada serves as the primary source of dry season runoff that supports agriculture, industries, urban, and other ecosystems. Increased warming has led to significant reductions in mountain snowpack accumulation and earlier snowmelt throughout the western United States where most of the snow accumulates at temperatures near the freezing point. As a result, declines in dry season runoff magnitude, earlier runoff timing, and altered flood risk have been reported across the region. An important question in this context is, how to best manage forested catchments for water and other ecosystem services? We depict the differences in hydrologic response of ten catchments in the Kings River Experimental Watersheds (KREW) research project using continuous precipitation, snow, and runoff data during 2004-2014. The size of these catchments ranges from 50 to 475 ha, and they span a 600-m elevation range in the rain snow transitional zone. In terms of soil, Shaver and Gerle-Cagwin dominate the lower elevation Providence catchments, and Cagwin soils dominate the higher elevation Bull catchments. The majority of these catchments have southwest aspect, moderate average slope (i.e. <25%), and a well-developed drainage network with drainage density ranging from 4.6 to 10.1 km/km2. Bull catchments, on average, have higher runoff than the Providence catchments across all hydrologic signatures extracted from daily hydrographs. Mean annual runoff ranges between 281 to 408 mm in Providence and 436 to 656 mm in Bull catchments despite no significant difference in precipitation among KREW's four meteorological stations. However, high elevation Bull catchments receive significantly more precipitation as snow than the low elevation Providence catchments. The average runoff ratio ranges from 18% to as high as 43% among different catchments, indicating that the catchment

  14. Successful reduction of diffuse nitrogen emissions at catchment scale: example from the pilot River Odense, Denmark.

    PubMed

    Windolf, J; Tornbjerg, H; Hoffmann, C C; Poulsen, J R; Blicher-Mathiesen, G; Kronvang, B

    2016-01-01

    Land-based total nitrogen (N) loadings to Danish coastal waters have been markedly reduced since 2000. This has been achieved by general measures reducing discharges from all point sources and N leaching from farmed land supplemented with more local and targeted mitigation measures such as restoration of wetlands to increase the catchment-specific N retention. In the catchment of River Odense, restoration of wetlands has been extensive. Thus, in the major gauged catchment (485 km(2)) eleven wetlands (860 ha) have been restored since 2000. A comparison of data on N concentrations and loss from a gauging station in the River Odense with data from a control catchment (772 km(2)), in which a significantly less intensive wetland restoration programme has been undertaken, showed an excess downward trend in N, amounting to 124 t N yr(-1), which can be ascribed to the intensive wetland restoration programme carried out in the River Odense catchment. In total, the N load in the River Odense has been reduced by 377 t N yr(-1) (39%) since 2000. The observed downward trend is supported by monitoring data from two wetlands restored in 2001 and 2004 in the River Odense catchment. PMID:27232393

  15. The catchment based approach using catchment system engineering

    NASA Astrophysics Data System (ADS)

    Jonczyk, Jennine; Quinn, Paul; Barber, Nicholas; Wilkinson, Mark

    2015-04-01

    The catchment based approach (CaBa) has been championed as a potential mechanism for delivery of environmental directives such as the Water Framework Directive in the UK. However, since its launch in 2013, there has been only limited progress towards achieving sustainable, holistic management, with only a few of examples of good practice ( e.g. from the Tyne Rivers trust). Common issues with developing catchment plans over a national scale include limited data and resources to identify issues and source of those issues, how to systematically identify suitable locations for measures or suites of measures that will have the biggest downstream impact and how to overcome barriers for implementing solutions. Catchment System Engineering (CSE) is an interventionist approach to altering the catchment scale runoff regime through the manipulation of hydrological flow pathways throughout the catchment. A significant component of the runoff generation can be managed by targeting hydrological flow pathways at source, such as overland flow, field drain and ditch function, greatly reducing erosive soil losses. Coupled with management of farm nutrients at source, many runoff attenuation features or measures can be co-located to achieve benefits for water quality and biodiversity. A catchment, community-led mitigation measures plan using the CSE approach will be presented from a catchment in Northumberland, Northern England that demonstrate a generic framework for identification of multi-purpose features that slow, store and filter runoff at strategic locations in the landscape. Measures include within-field barriers, edge of field traps and within-ditch measures. Progress on the implementation of measures will be reported alongside potential impacts on the runoff regime at both local and catchment scale and costs.

  16. Assessing the drivers of dissolved organic matter export from two contrasting lowland catchments, U.K.

    PubMed

    Yates, Christopher A; Johnes, Penny J; Spencer, Robert G M

    2016-11-01

    Two lowland catchments in the U.K. were sampled throughout 2010-11 to investigate the dominant controls on dissolved organic matter quantity and composition. The catchments had marked differences in terms of nutrient status, land cover and contrasting lithologies resulting in differences in the dominant flow pathways (groundwater vs. surface water dominated). The Upper Wylye is a chalk stream with a baseflow index of 0.98, draining a catchment dominated by intensive agricultural production. Millersford Brook is a lowland peat catchment with a baseflow index of 0.43, draining a semi-natural catchment with heather moorland and coniferous forest. Samples were collected weekly between October 2010 and September 2011 from eleven sampling locations. Samples were analysed to determine dissolved organic carbon, nitrogen and phosphorus fractions with DOM composition evaluated via the DOC:DON ratio, DOC:DOP ratio, specific UV absorption at 254nm, absorbance ratio (a250:a365) and the spectral slope parameter between 350 and 400nm (S350-400). Significant differences were observed in all determinands between the catchments, over time, and spatially along nutrient enrichment and geoclimatic gradients. Seasonal variation in preferential flow pathways mobilising groundwater-derived DOM were identified as likely controls on the delivery of DOM in the permeable chalk dominated catchment. Steeper S350-400 values and elevated a250:a365 ratios in this catchment suggest material of a lower bulk aromatic C content and molecular weight delivered during the winter months when compared to the summer. DOC:DON ratios were markedly lower in the chalk catchment than the peatland catchment, reflecting the paucity of organic matter within the mineral soils of the chalk landscape, and higher fertiliser application rates. This manuscript highlights that DOM composition varies according to catchment landscape character and hydrological function. PMID:27422728

  17. Describing Ecosystem Complexity through Integrated Catchment Modeling

    NASA Astrophysics Data System (ADS)

    Shope, C. L.; Tenhunen, J. D.; Peiffer, S.

    2011-12-01

    Land use and climate change have been implicated in reduced ecosystem services (ie: high quality water yield, biodiversity, and agricultural yield. The prediction of ecosystem services expected under future land use decisions and changing climate conditions has become increasingly important. Complex policy and management decisions require the integration of physical, economic, and social data over several scales to assess effects on water resources and ecology. Field-based meteorology, hydrology, soil physics, plant production, solute and sediment transport, economic, and social behavior data were measured in a South Korean catchment. A variety of models are being used to simulate plot and field scale experiments within the catchment. Results from each of the local-scale models provide identification of sensitive, local-scale parameters which are then used as inputs into a large-scale watershed model. We used the spatially distributed SWAT model to synthesize the experimental field data throughout the catchment. The approach of our study was that the range in local-scale model parameter results can be used to define the sensitivity and uncertainty in the large-scale watershed model. Further, this example shows how research can be structured for scientific results describing complex ecosystems and landscapes where cross-disciplinary linkages benefit the end result. The field-based and modeling framework described is being used to develop scenarios to examine spatial and temporal changes in land use practices and climatic effects on water quantity, water quality, and sediment transport. Development of accurate modeling scenarios requires understanding the social relationship between individual and policy driven land management practices and the value of sustainable resources to all shareholders.

  18. Programmable Oscillator

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Patawaran, Ferze D.; Nguyen, Danh H.; Lee, Clement G.; Nguyen, Huy

    2011-01-01

    A programmable oscillator is a frequency synthesizer with an output phase that tracks an arbitrary function. An offset, phase-locked loop circuit is used in combination with an error control feedback loop to precisely control the output phase of the oscillator. To down-convert the received signal, several stages of mixing may be employed with the compensation for the time-base distortion of the carrier occurring at any one of those stages. In the Goldstone Solar System Radar (GSSR), the compensation occurs in the mixing from an intermediate frequency (IF), whose value is dependent on the station and band, to a common IF used in the final stage of down-conversion to baseband. The programmable oscillator (PO) is used in the final stage of down-conversion to generate the IF, along with a time-varying phase component that matches the time-base distortion of the carrier, thus removing it from the final down-converted signal.

  19. Assessing water quality trends in catchments with contrasting hydrological regimes

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie C.; Shore, Mairead; Mellander, Per-Erik

    2016-04-01

    Environmental resources are under increasing pressure to simultaneously achieve social, economic and ecological aims. Increasing demand for food production, for example, has expanded and intensified agricultural systems globally. In turn, greater risks of diffuse pollutant delivery (suspended sediment (SS) and Phosphorus (P)) from land to water due to higher stocking densities, fertilisation rates and soil erodibility has been attributed to deterioration of chemical and ecological quality of aquatic ecosystems. Development of sustainable and resilient management strategies for agro-ecosystems must detect and consider the impact of land use disturbance on water quality over time. However, assessment of multiple monitoring sites over a region is challenged by hydro-climatic fluctuations and the propagation of events through catchments with contrasting hydrological regimes. Simple water quality metrics, for example, flow-weighted pollutant exports have potential to normalise the impact of catchment hydrology and better identify water quality fluctuations due to land use and short-term climate fluctuations. This paper assesses the utility of flow-weighted water quality metrics to evaluate periods and causes of critical pollutant transfer. Sub-hourly water quality (SS and P) and discharge data were collected from hydrometric monitoring stations at the outlets of five small (~10 km2) agricultural catchments in Ireland. Catchments possess contrasting land uses (predominantly grassland or arable) and soil drainage (poorly, moderately or well drained) characteristics. Flow-weighted water quality metrics were calculated and evaluated according to fluctuations in source pressure and rainfall. Flow-weighted water quality metrics successfully identified fluctuations in pollutant export which could be attributed to land use changes through the agricultural calendar, i.e., groundcover fluctuations. In particular, catchments with predominantly poor or moderate soil drainage

  20. Watershed scale spatial variability in dissolved and total organic and inorganic carbon in contrasting UK catchments

    NASA Astrophysics Data System (ADS)

    Cumberland, S.; Baker, A.; Hudson, N. J.

    2006-12-01

    Approximately 800 organic and inorganic carbon analyses have been undertaken from watershed scale and regional scale spatial surveys in various British catchments. These include (1) a small (<100 sq-km) urban catchment (Ouseburn, N England); (2) a headwater, lowland agricultural catchment (River Tern, C England) (3) a large UK catchment (River Tyne, ~3000 sq-km) and (4) a spatial survey of ~300 analyses from rivers from SW England (~1700 sq-km). Results demonstrate that: (1) the majority of organic and inorganic carbon is in the dissolved (DOC and DIC) fractions; (2) that with the exception of peat rich headwaters, DIC concentration is always greater than DOC; (3) In the rural River Tern, riverine DOC and DIC are shown to follow a simple end- member mixing between DIC (DOC) rich (poor) ground waters and DOC (DIC) rich (poor) riparian wetlands for all sample sites. (4) In the urbanized Ouseburn catchment, although many sample sites also show this same mixing trend, some tributaries follow a pollutant trend of simultaneous increases in both DOC and DIC. The Ouseburn is part of the larger Tyne catchment: this larger catchment follows the simple groundwater DIC- soil water DOC end member mixing model, with the exception of the urban catchments which exhibit an elevated DIC compared to rural sites. (5) Urbanization is demonstrated to increase DIC compared to equivalent rural catchments; this DIC has potential sources including diffuse source inputs from the dissolution of concrete, point sources such as trade effluents and landfill leachates, and bedrock derived carbonates relocated to the soil dissolution zone by urban development. (6) DIC in rural SW England demonstrates that spatial variability in DIC can be attributed to variations in geology; but that DIC concentrations in the SW England rivers dataset are typically lower than the urbanized Tyne catchments despite the presence of carbonate bedrock in many of the sample catchments in the SW England dataset. (7

  1. Agriculture Education. Agriculture Structures.

    ERIC Educational Resources Information Center

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary agricultural education students enrolled in one or two semester-long courses in agriculture structures. The guide presents units of study in the following areas: (1) shop safety, (2) identification and general use of hand tools, (3) power tools, (4) carpentry, (5) blueprint…

  2. Understanding fine sediment and phosphorous delivery in upland catchments

    NASA Astrophysics Data System (ADS)

    Perks, M. T.; Reaney, S. M.

    2013-12-01

    The uplands of UK are heavily impacted by land management including; farming and forestry operations, moorland burning, peat extraction, metal mining, artificial drainage and channelisation. It has been demonstrated that such land management activity may modify hillslope processes, resulting in enhanced runoff generation and changing the spatial distribution and magnitude of erosion. Resultantly, few upland river systems of the UK are operating in a natural state, with land management activity often resulting in increased fluxes of suspended sediment (< 2 mm) and associated pollutants (such as phosphorous). Most recent Environment Agency (EA) data reveals that 60% of monitored water bodies within upland areas of the UK are currently at risk of failing the Water Framework Directive (WFD) due to poor ecological status. In order to prevent the continual degradation of many upland catchments, riverine systems and their diverse ecosystems, a range of measures to control diffuse pollution will need to be implemented. Future mitigation options and measures in the UK may be tested and targeted through the EA's catchment pilot scheme; DEFRA's Demonstration Test Catchment (DTC) programmes and through the catchment restoration fund. However, restoring the physical and biological processes of past conditions in inherently sensitive upland environments is extremely challenging requiring the development of a solid evidence base to determine the effectiveness of resource allocation and to enable reliable and transparent decisions to be made about future catchment operations. Such evidence is rarely collected, with post-implementation assessments often neglected. This paper presents research conducted in the Morland sub-catchment of the River Eden within Cumbria; UK. 80% of this headwater catchment is in upland areas and is dominated by improved grassland and rough grazing. The catchment is heavily instrumented with a range of hydro-meteorological equipment. A high-tech monitoring

  3. Catchment systems science and management: from evidence to resilient landscapes

    NASA Astrophysics Data System (ADS)

    Quinn, Paul

    2014-05-01

    There is an urgent need to reassess both the scientific understanding and the policy making approaches taken to manage flooding, water scarcity and pollution in intensively utilised catchments. Many European catchments have been heavily modified and natural systems have largely disappeared. However, working with natural processes must still be at the core of any future management strategy. Many catchments have greatly reduced infiltration rates and buffering capacity and this process needs to be reversed. An interventionist and holistic approach to managing water quantity and quality at the catchment scale is urgently required through the active manipulation of natural flow processes. Both quantitative (field experiments and modelling) and qualitative evidence (local knowledge) is required to demonstrate that catchment have become 'unhealthy'. For example, dense networks of low cost instrumentation could provide this multiscale evidence and, coupled with stakeholder knowledge, build a comprehensive understanding of whole system function. Proactive Catchment System Management is an interventionist approach to altering the catchment scale runoff regime through the manipulation of landscape scale hydrological flow pathways. Many of the changes to hydrological processes cannot be detected at the catchment scale as the primary causes of flooding and pollution. Evidence shows it is the land cover and the soil that are paramount to any change. Local evidence shows us that intense agricultural practices reduce the infiltration capacity through soil degradation. The intrinsic buffering capacity has also been lost across the landscape. The emerging hydrological process is one in which the whole system responds too quickly (driven by near surface and overland flow processes). The bulk of the soil matrix is bypassed during storm events and there is little or no buffering capacity in the riparian areas or in headwater catchments. The prospect of lower intensity farming rates is

  4. Assessing catchment connectivity using hysteretic loops

    NASA Astrophysics Data System (ADS)

    Keesstra, Saskia; Masselink, Rens; Goni, Mikel; Campo, Miguel Angel; Gimenez, Rafael; Casali, Javier; Seeger, Manuel

    2015-04-01

    Sediment connectivity is a concept which can explain the origin, pathways and sinks of sediments within landscapes. This information is valuable for land managers to be able to take appropriate action at the correct place. Hysteresis between sediment and water discharge can give important information about the sources , pathways and conditions of sediment that arrives at the outlet of a catchment. "Hysteresis" happens when the sediment concentration associated with a certain flow rate is different depending on the direction in which the analysis is performed -towards the increase or towards the diminution of the flow. This phenomenon to some extent reflects the way in which the runoff generation processes are conjugated with those of the production and transport of sediments, hence the usefulness of hysteresis as a diagnostic hydrological parameter. However, the complexity of the phenomena and factors which determine hysteresis make its interpretation uncertain or, at the very least, problematic. Many types of hysteretic loops have been described as well as the cause for the shape of the loop, mainly describing the origin of the sediments. In this study, several measures to objectively classify hysteretic loops in an automated way were developed. These were consecutively used to classify several hundreds of loops from several agricultural catchments in Northern Spain. The data set for this study comes from four experimental watersheds in Navarre (Spain), owned and maintained by the Government of Navarre. These experimental watersheds have been monitored and studied since 1996 (La Tejería and Latxaga) and 2001 (Oskotz "principal", Op, and Oskotz "woodland", Ow). La Tejería and Latxaga watersheds, located in the Central Western part of Navarre, are roughly similar to each other regarding size (approximately 200 ha), geology (marls and sandstones), soils (fine texture topsoil), climate (humid sub Mediterranean) and land use (80-90% cultivated with winter grain crops

  5. Controls of catchments` sub-storage contributions to dynamic water quality patterns in the stream network

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Maike Hegenauer, Anja

    2016-04-01

    Water quality is usually observed either continuously at a few stations within a catchment or with few snapshot sampling campaigns throughout the whole stream network. Although we know that the depletion of catchment sub-storages can vary throughout the stream network according to their actual water content (spatial variability of actual storage conditions can be caused amongst others by unevenly distributed rainfall, storage size or spatial differences in soil characteristics and land use), we know little about the impact of this process on spatial water quality patterns. For summer low flow recession periods, when stream water composition can be crucial for aquatic ecosystem conditions and the exceedance of water quality thresholds, knowledge on the controls of the dynamic interplay of catchment storages and stream water composition might improve water quality management and the implementation of corresponding mitigation measures. We studied this process throughout the stream network of a first-order agricultural headwater catchment in south-western Germany during two summer low flow recession periods. The underlying geology of the study area is a deep layer of aeolian loess, whilst the dominating soil is a silty calcaric regosol with gleizations in the colluvium. The land use in the catchment is dominated by viniculture (63 %) and arable crops (18 %). Due to the dense drainpipe network within the catchment we could identify 12 sub-catchments contributing during summer low flow recession periods to total stream discharge. We continuously observed discharge, electrical conductivity and water temperatures for 8 of the sub-catchments and at the catchment outlet. This data set was accomplished by 10 snapshot campaigns where we sampled for water temperatures, electrical conductivity, major ions, pH and O2 throughout the stream network. Using either discharge concentration relationships or time dependent functions, we derived continuous export rates for all measures in

  6. Identifying hydrological responses of micro-catchments under contrasting land use in the Brazilian Cerrado

    NASA Astrophysics Data System (ADS)

    Nobrega, R. L. B.; Guzha, A. C.; Torres, G. N.; Kovacs, K.; Lamparter, G.; Amorim, R. S. S.; Couto, E.; Gerold, G.

    2015-09-01

    In recent decades, the Brazilian Cerrado biome has been affected by intense land-use change, particularly the conversion of natural forest to agricultural land. Understanding the environmental impacts of this land-use change on landscape hydrological dynamics is one of the main challenges in the Amazon agricultural frontier, where part of the Brazilian Cerrado biome is located and where most of the deforestation has occurred. This study uses empirical data from field measurements to characterize controls on hydrological processes from three first-order micro-catchments < 1 km2 in the Cerrado biome. These micro-catchments were selected on the basis of predominant land use including native cerrado vegetation, pasture grass with cattle ranching, and cash crop land. We continuously monitored precipitation, streamflow, soil moisture, and meteorological variables from October 2012 to September 2014. Additionally, we determined the physical and hydraulic properties of the soils, and conducted topographic surveys. We used these data to quantify the water balance components of the study catchments and to relate these water fluxes to land use, catchment physiographic parameters, and soil hydrophysical properties. The results of this study show that runoff coefficients were 0.27, 0.40, and 0.16 for the cerrado, pasture, and cropland catchments, respectively. Baseflow is shown to play a significant role in streamflow generation in the three study catchments, with baseflow index values of more than 0.95. The results also show that evapotranspiration was highest in the cerrado (986 mm yr-1) compared to the cropland (828 mm yr-1) and the pasture (532 mm yr-1). However, discharges in the cropland catchment were unexpectedly lower than that of the cerrado catchment. The normalized discharge was 55 % higher and 57 % lower in the pasture and cropland catchments, respectively, compared with the cerrado catchment. We attribute this finding to the differences in soil type and

  7. Understanding and improving mitigation strategies for reducing catchment scale nutrient loads using high resolution observations and uncertainty analysis approaches

    NASA Astrophysics Data System (ADS)

    Collins, A.; Lloyd, C.; Freer, J. E.; Johnes, P.; Stirling, M.

    2012-12-01

    One of the biggest challenges in catchment water quality management is tackling the problem of reducing water pollution from agriculture whilst ensuring food security nationally. Improvements to catchment management plans are needed if we are to enhance biodiversity and maintain good ecological status in freshwater ecosystems, while producing enough food to support a growing global population. In order to plan for a more sustainable and secure future, research needs to quantify the uncertainties and understand the complexities in the source-mobilisation-delivery-impact continuum of pollution and nutrients at all scales. In the UK the Demonstration Test Catchment (DTC) project has been set up to improve water quality specifically from diffuse pollution from agriculture by enhanced high resolution monitoring and targeted mitigation experiments. The DTC project aims to detect shifts in the baseline trend of the most ecologically-significant pollutants resulting from targeted on-farm measures at field to farm scales and assessing their effects on ecosystem function. The DTC programme involves three catchments across the UK that are indicative of three different typologies and land uses. This paper will focus on the Hampshire Avon DTC, where a total of 12 parameters are monitored by bank-side stations at two sampling sites, including flow, turbidity, phosphate and nitrate concentrations at 30 min resolution. This monitoring is supported by daily resolution sampling at 5 other sites and storm sampling at all locations. Part of the DTC project aims to understand how observations of water quality within river systems at different temporal resolutions and types of monitoring strategies enable us to understand and detect changes over and above the natural variability. Baseline monitoring is currently underway and early results show that high-resolution data is essential at this sub-catchment scale to understand important process dynamics. This is critical if we are to design

  8. Suspended sediment apportionment in a South-Korean mountain catchment

    NASA Astrophysics Data System (ADS)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  9. Modelling catchment non-stationarity - multi-scale modelling and data assimilation

    NASA Astrophysics Data System (ADS)

    Wheater, H. S.; Bulygina, N.; Ballard, C. E.; Jackson, B. M.; McIntyre, N.

    2012-12-01

    Modelling environmental change is in many senses a 'Grand Challenge' for hydrology, but poses major methodological challenges for hydrological models. Conceptual models represent complex processes in a simplified and spatially aggregated manner; typically parameters have no direct relationship to measurable physical properties. Calibration using observed data results in parameter equifinality, unless highly parsimonious model structures are employed. Use of such models to simulate effects of catchment non-stationarity is essentially speculative, unless attention is given to the analysis of parameter temporal variability in a non-stationary observation record. Black-box models are similarly constrained by the information content of the observational data. In contrast, distributed physics-based models provide a stronger theoretical basis for the prediction of change. However, while such models have parameters that are in principle measurable, in practice, for catchment-scale application, the measurement scale is inconsistent with the scale of model representation, the costs associated with such an exercise are high, and key properties are spatially variable, often strongly non-linear, and highly uncertain. In this paper we present a framework for modelling catchment non-stationarity that integrates information (with uncertainty) from multiple models and data sources. The context is the need to model the effects of agricultural land use change at multiple scales. A detailed UK multi-scale and multi-site experimental programme has provided data to support high resolution physics-based models of runoff processes that can, for example, represent the effects of soil structural change (due to grazing densities or trafficking), localised tree planting and drainage. Such models necessarily have high spatial resolution (1m in the horizontal plane, 1 cm in the vertical in this case), and hence can be applied at the scale of a field or hillslope element, but would be

  10. Effects of land cover change on evapotranspiration and streamflow of small catchments in the Upper Xingu River Basin, Central Brazi

    NASA Astrophysics Data System (ADS)

    Costa, M. H.; Dias, L. C. P.; Macedo, M.; Coe, M. T.; Neill, C.

    2015-12-01

    This study assess the influence of land cover changes on evapotranspiration and streamflow in small catchments in the Upper Xingu River Basin (Mato Grosso state, Brazil). Streamflow was measured in catchments with uniform land use for September 1, 2008 to August 31, 2010. We used models to simulate evapotranspiration and streamflow for the four most common land cover types found in the Upper Xingu: tropical forest, cerrado (savanna), pasture, and soybean croplands. We used INLAND to perform single point simulations considering tropical rainforest, cerrado and pasturelands, and AgroIBIS for croplands. Converting natural vegetation to agriculture substantially modifies evapotranspiration and streamflow in small catchments. Measured mean streamflow in soy catchments was about three times greater than that of forest catchments, while the mean annual amplitude of flow in soy catchments was more than twice that of forest catchments. Simulated mean annual evapotranspiration was 39% lower in agricultural ecosystems (pasture and soybean cropland) than in natural ecosystems (tropical rainforest and cerrado). Observed and simulated mean annual streamflows in agricultural ecosystems were more than 100% higher than in natural ecosystems. The accuracy of the simulations is improved by using field-measured soil hydraulic properties. The inclusion of local measurements of key soil parameters is likely to improve hydrological simulations in other tropical regions.

  11. Effects of land cover change on evapotranspiration and streamflow of small catchments in the Upper Xingu River Basin, Central Brazi

    NASA Astrophysics Data System (ADS)

    Costa, M. H.; Dias, L. C. P.; Macedo, M.; Coe, M. T.; Neill, C.

    2014-12-01

    This study assess the influence of land cover changes on evapotranspiration and streamflow in small catchments in the Upper Xingu River Basin (Mato Grosso state, Brazil). Streamflow was measured in catchments with uniform land use for September 1, 2008 to August 31, 2010. We used models to simulate evapotranspiration and streamflow for the four most common land cover types found in the Upper Xingu: tropical forest, cerrado (savanna), pasture, and soybean croplands. We used INLAND to perform single point simulations considering tropical rainforest, cerrado and pasturelands, and AgroIBIS for croplands. Converting natural vegetation to agriculture substantially modifies evapotranspiration and streamflow in small catchments. Measured mean streamflow in soy catchments was about three times greater than that of forest catchments, while the mean annual amplitude of flow in soy catchments was more than twice that of forest catchments. Simulated mean annual evapotranspiration was 39% lower in agricultural ecosystems (pasture and soybean cropland) than in natural ecosystems (tropical rainforest and cerrado). Observed and simulated mean annual streamflows in agricultural ecosystems were more than 100% higher than in natural ecosystems. The accuracy of the simulations is improved by using field-measured soil hydraulic properties. The inclusion of local measurements of key soil parameters is likely to improve hydrological simulations in other tropical regions.

  12. a Generic Framework for Water and Forest Management in Catchments Restoration in Latin America

    NASA Astrophysics Data System (ADS)

    Mintegui Aguirre, J. A.; Amezaga, J. M.; Robredo Sanchez, J. C.; Lopez Leiva, C.

    2007-05-01

    The document presents a generic framework for the analysis and development of a programme for catchment management and restoration that takes into account both the protection from the impact of extreme events and the sustainable use of land and water resources. The framework was originally developed for the restoration of mountain catchments in Europe between the end of the 19th century and the beginning of the 20th century and still provides the intellectual basis for the integrated assessment of hydraulic and land use factors in these countries. It is based on a thorough analysis of the behavior of a catchment in normal and extreme conditions. Recently, the authors have tested this generic framework in a number of catchments in Latin America, which present very different physical and socio-economic conditions. Fieldwork in Costa Rica, Ecuador, Chile and Argentina with particular catchments covering a whole range of climatological, geo-morphological and land used settings has provided new insights on the applicability of this generic framework. The paper discusses the role of vegetation, and in particular of forests, in catchment management taking a long-term view of cost and benefits under normal and extreme conditions. It also provides conclusions for the development of land use policies to optimize the practical use of vegetation of management purposes.

  13. Spatial and temporal changes in apportionments by using sediment fingerprinting in a Spanish Pyrenean river catchment.

    NASA Astrophysics Data System (ADS)

    Palazón, Leticia; Latorre, Borja; Gaspar, Leticia; Navas, Ana

    2016-04-01

    The Barasona reservoir has suffered from siltation since its construction, with the loss of over one third of its storage volume in around 30 years (period 1972-1996). Information on sediment contribution and transport dynamics from the contributing catchment to the reservoir is needed to develop management plans for maintaining reservoir sustainability. Large variability in sediment delivery was found in previous studies in the Barasona catchment (1509 km2, Central Spanish Pyrenees) and the major sediment sources identified included badlands developed in the middle part of the catchment and the agricultural fields in its lower part. In this study the < 63 μm sediment fraction from the channel bed sediment samples from the main rivers (Ésera and Isábena), their tributaries and surface reservoir sediments, the latter spanning two decades, are investigated following the fingerprinting procedure to assess how the land use sediment contributions change along the streams and on time to the reservoir. Subsoil source (badlands included) contributions to channel bed sediments of the main rivers are limited in the catchment headwater which turn to be greater than 70 % for river reaches closer to the reservoir. In the same way, the presence of the badlands and the greater percentage of bare soils in the southern part of the catchment are main source of sediments (> 50%) for the southern tributaries. Differences in source apportionments between the two time-spanning reservoir samples reveal that agricultural fields contributed more in the 90s. Study fine sediment characteristics and their contributions in river catchments provide unique and diverse information to address catchment management problems, improving the spatial and temporal knowledge of land use sediment source contributions along the catchment to the reservoir infill.

  14. Trend analysis of nutrient loadings in the South Saskatchewan River catchment

    NASA Astrophysics Data System (ADS)

    Morales-Marin, L. A.; Chun, K. P.; Wheater, H. S.; Lindenschmidt, K. E.

    2015-12-01

    Nutrient loadings in river catchments have increased in the past years as a consequence of rapid expansion of agricultural areas, new urban developments and industries, and population growth. Nutrient enrichment of water bodies has intensified eutrophication conditions that degrade water quality and ecosystem health. In large-scale catchments, the assessment of temporal and spatial variability of nutrient loads imply challenges due to climate, land use and geology heterogeneity, and to anthropogenic changes. In this study we carried out a trend analysis of total phosphorus and total nitrogen loads in the South Saskatchewan River (SSR) catchment. This catchment is located in the Canadian Prairie Provinces of Alberta and Saskatchewan. The eastern and central areas of the catchment consist mostly of croplands, pasture lands and livestock farms, whereas the western parts are located on the Rocky Mountains that are the source of most of the catchment's streamflows. The trend analysis was performed applying a novel approach to analyse nutrient time series recorded at long-term water quality stations along the main stems of the SSR river network. Since water quality is taken infrequently, in the proposed approach the time series were complemented using regression analysis methods based on streamflow data recorded at the nearest gauge stations. The time series were subsequently pre-whitened in order to remove the autocorrelation, and then subjected to non-parametric statistical test to detect trends. Seasonal analysis of trends at each of the water quality stations were performed in order to determine the relationships between annual flow regimes and nutrient loads in the catchment, in particular, the influence of the high spring runoff on nutrient export. Decadal analysis was also performed to determine the long-tern relationships of nutrients with anthropogenic changes in the catchment. In particular, the capacity of reservoirs to trap nutrients and the effects of the

  15. Microbial water pollution: a screening tool for initial catchment-scale assessment and source apportionment.

    PubMed

    Kay, D; Anthony, S; Crowther, J; Chambers, B J; Nicholson, F A; Chadwick, D; Stapleton, C M; Wyer, M D

    2010-11-01

    The European Union Water Framework Directive requires that Management Plans are developed for individual River Basin Districts. From the point of view of faecal indicator organisms (FIOs), there is a critical need for screening tools that can provide a rapid assessment of the likely FIO concentrations and fluxes within catchments under base- and high-flow conditions, and of the balance ('source apportionment') between agriculture- and sewage-derived sources. Accordingly, the present paper reports on: (1) the development of preliminary generic models, using water quality and land cover data from previous UK catchment studies for assessing FIO concentrations, fluxes and source apportionment within catchments during the summer bathing season; (2) the calibration of national land use data, against data previously used in the models; and (3) provisional FIO concentration and source-apportionment assessments for England and Wales. The models clearly highlighted the crucial importance of high-flow conditions for the flux of FIOs within catchments. At high flow, improved grassland (and associated livestock) was the key FIO source; FIO loadings derived from catchments with high proportions of improved grassland were shown to be as high as from urbanized catchments; and in many rural catchments, especially in NW and SW England and Wales, which are important areas of lowland livestock (especially dairy) farming, ≥ 40% of FIOs was assessed to be derived from agricultural sources. In contrast, under base-flow conditions, when there was little or no runoff from agricultural land, urban (i.e. sewerage-related) sources were assessed to dominate, and even in rural areas the majority of FIOs were attributed to urban sources. The results of the study demonstrate the potential of this type of approach, particularly in light of climate change and the likelihood of more high-flow events, in underpinning informed policy development and prioritization of investment. PMID:19717181

  16. Evaluating an ecosystem management approach for improving water quality in two contrasting study catchments in south-west England.

    NASA Astrophysics Data System (ADS)

    Glendell, Miriam; Brazier, Richard

    2014-05-01

    The European Water Framework Directive (WFD) 2000 established a new emphasis for the management of freshwaters by establishing ecologically-based water quality targets that are to be achieved through holistic, catchment-scale, ecosystem management approaches. However, significant knowledge gaps still exist in the understanding of the cumulative effectiveness of multiple mitigation measures on a number of pollutants at a catchment scale. This research furthers the understanding of the effectiveness of an ecosystem management approach to deliver catchment-scale water quality improvements in two contrasting study catchments in south-west England: the lowland agricultural Aller and the upland semi-natural Horner Water. Characterisation of the spatial variability of soil properties (bulk density, total carbon, nitrogen, C:N ratio, stable isotope δ15N, total, organic and inorganic phosphorus) in the two study catchments demonstrated extensive alteration of soil properties in the agricultural catchment, with likely long-term implications for the restoration of ecosystem functioning and water quality management (Glendell et al., 2014b). Further, the agricultural catchment supported a proportionally greater total fluvial carbon (dissolved and particulate) export than the semi-natural catchment. During an eight month period for which a comparable continuous turbidity record was available, the estimated SS yields from the agricultural catchment (25.5-116.2 t km-2) were higher than from the semi-natural catchment (21.7-57.8 t km-2). In addition, the agricultural catchment exported proportionally more TPC (0.51-2.59 kg mm-1) than the semi-natural catchment (0.36-0.97 kg mm-1) and a similar amount of DOC (0.26-0.52 kg mm-1 in the Aller and 0.24-0.32 kg mm-1 in Horner Water), when normalised by catchment area and total discharge, despite the lower total soil carbon pool, thus indicating an enhanced fluvial loss of sediment and carbon (Glendell and Brazier, in review). Whilst

  17. Defining the sources of low-flow phosphorus transfers in complex catchments.

    PubMed

    Arnscheidt, J; Jordan, P; Li, S; McCormick, S; McFaul, R; McGrogan, H J; Neal, M; Sims, J T

    2007-08-15

    Nutrient transfers from the land to rivers have the potential to cause persistent eutrophic impacts at low flows even though the transfers may constitute a minor percentage of total annual fluxes. In rural catchments, the contribution from agricultural soils during storm events can be particularly large and untangling the relative contributions from multiple sources that vary in time and space is especially problematic. In this study, the potential for domestic septic tank system pollution during low flows was investigated in 3 small catchments (3 to 5 km(2)) using an integrated series of methods. These included septic system surveys, continuous (10 min) total phosphorus (TP) monitoring at the outlet of each catchment, repeated low-flow water quality surveys in sub-catchments upstream of the catchment outlets and single day river-walk water quality surveys. A series of faecal matter and grey-water fingerprinting techniques were also employed. These included determining sterol ratios in stream sediments, monitoring the presence of proteins, E. coli and enterococci bacterial signatures and boron. The total density and density of poorly maintained septic systems mirrored the magnitude of frequent TP concentrations in the catchments although this relationship was less apparent in the nested sub-catchments. The exception was possibly related to the simple hydraulics in one particular catchment and indicated temporary effluent attenuation in the other catchments. Repeated low-flow and river-walk water quality surveys highlighted discrete areas and reaches where stepped changes in nutrient concentration occurred. Bio-chemical fingerprinting showed that between 7% and 27% of sediments were contaminated with human faecal material and correlation matrices indicated that, at least during low flows, P fractions were positively correlated with some markers of faecal and grey-water contamination. PMID:17512972

  18. Assessing metaldehyde concentrations in surface water catchments and implications for drinking water abstraction

    NASA Astrophysics Data System (ADS)

    Asfaw, Alemayehu; Shucksmith, James; Smith, Andrea; Cherry, Katherine

    2015-04-01

    Metaldehyde is an active ingredient in agricultural pesticides such as slug pellets, which are heavily applied to UK farmland during the autumn application season. There is current concern that existing drinking water treatment processes may be inadequate in reducing potentially high levels of metaldehyde in surface waters to below the UK drinking water quality regulation limit of 0.1 µg/l. In addition, current water quality monitoring methods can miss short term fluctuations in metaldehyde concentration caused by rainfall driven runoff, hampering prediction of the potential risk of exposure. Datasets describing levels, fate and transport of metaldehyde in river catchments are currently very scarce. This work presents results from an ongoing study to quantify the presence of metaldehyde in surface waters within a UK catchment used for drinking water abstraction. High resolution water quality data from auto-samplers installed in rivers are coupled with radar rainfall, catchment characteristics and land use data to i) understand which hydro-meteorological characteristics of the catchment trigger the peak migration of metaldehyde to surface waters; ii) assess the relationship between measured metaldehyde levels and catchment characteristics such as land use, topographic index, proximity to water bodies and runoff generation area; iii) describe the current risks to drinking water supply and discuss mitigation options based on modelling and real-time control of water abstraction. Identifying the correlation between catchment attributes and metaldehyde generation will help in the development of effective catchment management strategies, which can help to significantly reduce the amount of metaldehyde finding its way into river water. Furthermore, the effectiveness of current water quality monitoring strategy in accurately quantifying the generation of metaldehyde from the catchment and its ability to benefit the development of effective catchment management practices

  19. Determination of Curve Number for snowmelt-runoff floods in a small catchment

    NASA Astrophysics Data System (ADS)

    Hejduk, L.; Hejduk, A.; Banasik, K.

    2015-06-01

    One of the widely used methods for predicting flood runoff depth from ungauged catchments is the curve number (CN) method, developed by Soil Conservation Service (SCS) of US Department of Agriculture. The CN parameter can be computed directly from recorded rainfall depths and direct runoff volumes in case of existing data. In presented investigations, the CN parameter has been computed for snowmelt-runoff events based on snowmelt and rainfall measurements. All required data has been gathered for a small agricultural catchment (A = 23.4 km2) of Zagożdżonka river, located in Central Poland. The CN number received from 28 snowmelt-runoff events has been compared with CN computed from rainfall-runoff events for the same catchment. The CN parameter, estimated empirically varies from 64.0 to 94.8. The relation between CN and snowmelt depth was investigated in a similar procedure to relation between CN and rainfall depth.

  20. A Watershed Directory As A Basis For Integrated River Catchment Management of The Modau Catchment (germany)

    NASA Astrophysics Data System (ADS)

    Klawitter, A.; Ostrowski, M.

    A key element of the EU Water Framework Directive is the River Basin Management Plan providing the program of measures, which are aimed at protecting and meliorat- ing surface waters, groundwaters and other protected areas. A further important role in the River Basin Management Plan plays the monitoring of surface waters, as well as groundwaters and protected areas, which was the trigger for this investigation. The Modau catchment, situated East of the Rhine in South Hesse, is intensively used by agriculture and industry, and is furthermore densely populated. The river channel is severely impaired by urban settlements and water engineering works. Finally, the lower part of the Modau catchment is used for groundwater extraction. Due to these facts, an integrated water management is compulsory. The main purpose of the investigation was to establish a watershed directory com- bining all available information for watershed management and to evaluate this data basis towards its suitability for a River Basin Management Plan. A further purpose was to identify deficits as well as information gaps in this data basis. During the inves- tigation, a preliminary assessment of the monitoring and management strategies was carried out, to see whether current work with regard to river basin management meets the requirements of the Water Framework Directive.

  1. Integrated monitoring of nitrogen dynamics in contrasting catchments

    NASA Astrophysics Data System (ADS)

    Schwientek, M.; Fleischer, M.

    2012-04-01

    The research institute WESS (Water & Earth System Science) is monitoring three adjacent meso-scale catchments (72 - 140 km2) in southwest Germany with respect to water quantity and quality. Due to their spatial proximity, the studied catchments are similar regarding climatic conditions and water balance. Geology is characterized by sedimentary rocks which are partly karstified. The catchments contrast strongly in land use and show a range from predominantly agriculture to almost exclusively forestry. In this context, a special focus of our research is the distinction of matter coming from the catchment area versus substances stemming from urban point sources. One important compound representing inputs from the catchment area is nitrogen. Nitrogen is an essential nutrient governing plant growth. If available in excess it leads to eutrophication and is therefore one of the globally most widespread contaminants in aquatic ecosystems. Transport of human-derived nitrogen through landscapes including urban areas to the oceans predominantly occurs via river network systems. Hence, monitoring of nitrogen fluxes in streams and rivers reveals mechanisms and dynamics of its transport and gives also insight into hydrologic processes which influence the mobilization of nitrogen. Presently, the catchments are equipped with online probes enabling high resolution monitoring of nitrate concentrations and other parameters. We found that average nitrate concentrations in stream water perfectly reflect the portion of fertilized arable land. The dynamics of N transport, however, largely depends on the hydrologic system and is driven by the dominating runoff generation processes. The interplay between different hydrological storages, which eventually also act as N pools, turns out to be decisive for the temporal variability of N concentrations in stream discharge. Inversely, the study of N transport dynamics can be used to infer the hydrologic mechanisms responsible for N mobilization

  2. A 125 year long record of DOC flux from a major temperate catchment: land-use vs. climate control?

    NASA Astrophysics Data System (ADS)

    Clay, G.; Worrall, F.; Howden, N. K.; Burt, T. P.

    2010-12-01

    Our understanding of the controls upon carbon biogeochemistry has always been limited by lack of long term observational data at the same time as having long term monitoring of possible environmental drivers. For the River Thames catchment in the UK (9998 km2) records of DOM have been kept since 1868 and DOM flux since 1882. In addition to riverflow being monitored in the catchment there has also been monitoring of climate, land-use and population back to at least 1868. The Thames catchment is a mixed agricultural urban catchment dominated by mineral soils where groundwater plays a significant part in the catchments flow system. During the period of the record the catchment has undergone urbanisation, climate warming but has also undergone large-scale land use change associated with World War II and agricultural intensification in the 1960s. The importance of these combinations of pressures are explored in the time series through a range of time series techniques and the results show: i) That DOC flux in the catchment is now at historic low levels, with the maximum flux being 35 ktonnes C/yr (3.5 tonnes/km2/yr) in 1915 and the lowest flux being 2 ktonnes C/yr (0.2 tonnes/km2/yr) in 1997. ii) The trend in the DOC flux is explained by changes in flow, which appear associated with both with groundwater storage in the catchment and with changes in land-use. iii) The significant decline in the DOC flux appears to be due to the transition in the catchment from dominated from pasture to an arable land use. iv) The decline of DOC flux with temperature would suggest that DOC mineralisation reaction has a higher Q10 than the DOC production. v) Declining DOC flux from mineral soils catchments would offset increases in DOC flux from organic soils but would also represent a shift in carbon losses from fluvial to being direct to the atmosphere.

  3. Coevolution of volcanic catchments in Japan

    NASA Astrophysics Data System (ADS)

    Yoshida, Takeo; Troch, Peter A.

    2016-03-01

    Present-day landscapes have evolved over time through interactions between the prevailing climates and geological settings. Understanding the linkage between spatial patterns of landforms, soils, and vegetation in landscapes and their hydrological response is critical to make quantitative predictions in ungaged basins. Catchment coevolution is a theoretical framework that seeks to formulate hypotheses about the mechanisms and conditions that determine the historical development of catchments and how such evolution affects their hydrological response. In this study, we selected 14 volcanic catchments of different ages (from 0.225 to 82.2 Ma) in Japan. We derived indices of landscape properties (drainage density and slope-area relationship) as well as hydrological response (annual water balance, baseflow index, and flow-duration curves) and examined their relation with catchment age and climate (through the aridity index). We found a significant correlation between drainage density and baseflow index with age, but not with climate. The intra-annual flow variability was also significantly related to catchments age. Younger catchments tended to have lower peak flows and higher low flows, while older catchments exhibited more flashy runoff. The decrease in baseflow with catchment age is consistent with the existing hypothesis that in volcanic landscapes the major flow pathways change over time from deep groundwater flow to shallow subsurface flow. The drainage density of our catchments decreased with age, contrary to previous findings in a set of similar, but younger volcanic catchments in the Oregon Cascades, in which drainage density increased with age. In that case, older catchments were thought to show more landscape incision due to increasing near-surface lateral flow paths. Our results suggests two competing hypotheses on the evolution of drainage density in mature catchments. One is that as catchments continue to age, the hydrologically active channels retreat

  4. Restoring Landform Geodiversity in Modified Rivers and Catchments

    NASA Astrophysics Data System (ADS)

    Smith, Ben; Clifford, Nicholas

    2014-05-01

    Extensive human modification and exploitation has created degraded and simplified systems lacking many of the landforms which would characterise healthy, geodiverse rivers. As awareness of geodiversity grows we must look to ways not only to conserve geodiversity but to also restore or create landforms which contribute to geodiverse environments. River restoration, with lessons learned over the last 30 years and across multiple continents, has much to offer as an exemplar of how to understand, restore or create geodiversity. Although not mentioned explicitly, there is an implicit emphasis in the Water Framework Directive on the importance of landforms and geodiversity, with landform units and assemblages at the reach scale assumed to provide the physical template for a healthy aquatic ecosystem. The focus on hydromorphology has increased the importance of geomorphology within river restoration programmes. The dominant paradigm is to restore landforms in order to increase habitat heterogeneity and improve biodiversity within rivers. However, the process of landform restoration is also a goal in its own right in the context of geodiversity, and extensive compilations of restoration experiences allow an inventory and pattern of landform (re-) creation to be assembled, and an assessment of landform function as well as landform presence/absence to be made. Accordingly, this paper outlines three principal research questions: Which landforms are commonly reinstated in river restoration activities? How do these landforms function compared to natural equivalents and thus contribute to 'functional' geodiversity as compared to the 'aesthetic' geodiversity? How does landform diversity scale from reach to catchment and contribute to larger-scale geodiversity? Data from the UK National River Restoration Inventory and the RHS are combined to assess the frequency and spatial distribution of commonly created landforms in relation to catchment type and more local context. Analysis is

  5. Predicting nutrient responses to mitigation at catchment to national scale: the UK research platform (Invited)

    NASA Astrophysics Data System (ADS)

    Johnes, P.

    2013-12-01

    Nutrient enrichment of waters from land-based and atmospheric sources presents a significant management challenge, requiring effective stakeholder engagement and policy development, properly underpinned by robust scientific evidence. The challenge is complex, raising significant questions about the specific sources, apportionment and pathways that determine nutrient enrichment and the key priorities for effective management and policy intervention. This paper presents outputs from 4 major UK research programmes: the Defra Demonstration Test Catchments programme (DTC), the Environment Agency's Catchment Sensitive Farming monitoring and evaluation programme (CSF), Natural Resources Wales Welsh Catchment Initiative (WCI) and the NERC Environmental Virtual Observatory programme (EVOp). Funded to meet this challenge, they are delivering new understanding of the rates and sources of pollutant fluxes from land to water, their impacts on ecosystem goods and services, and likely trends under future climate and land use change from field to national scale. DTC, a 12m investment by the UK Government, has set up long-term, high resolution research platforms equipped with novel telemetered sensor networks to monitor stream ecosystem responses to on-farm mitigation measures at a representative scale for catchment management. Ecosystem structural and functional responses and bulk hydrochemistry are also being monitored using standard protocols. CSF has set up long-term, enhanced monitoring in 8 priority catchments, with monthly monitoring in a further 72 English catchments and 6 Welsh priority catchments, to identify shifts in pollutant flux to waters resulting from mitigation measures in priority areas and farming sectors. CSF and WCI have contributed to >50 million of targeted farm improvements to date, representing a significant shift in farming practice. Each programme has generated detailed evidence on stream ecosystem responses to targeted mitigation. However, to provide

  6. Fate of organic contaminants in a boreal forest catchment

    NASA Astrophysics Data System (ADS)

    Bergknut, Magnus; Meijer, Sandra; Halsall, Crispin; Ågren, Anneli; Laudon, Hjalmar; Köhler, Stephan; Jones, Kevin; Tysklind, Mats; Wiberg, Karin

    2010-05-01

    organic carbon and soil-water dissolved organic carbon (DOC) content. Significant differences in export of POPs were apparent between the forested and mire areas, and this could be linked to observed differences in hydrology, biogeochemistry and flux of DOC. Levels of POPs in surface water along the water path from the studied catchment to the Baltic Sea (the Gulf of Bothnia subbasin) were measured and the results showed that for this water system, atmospherically derived diffuse pollution has impact on the surface water quality in addition to downstream point sources. In conclusion, it is evident that a full understanding of the baseline contribution and the soil-to-water processes controlling the transport of priority substances at catchment scale is a prerequisite for assessing the variation of priority substances in water streams and river basins on a seasonal and regional scale. It is also clear that mobilization of headwater atmospherically derived diffuse pollution may have an impact on stream water quality in addition to downstream point sources. The above findings are applicable to a wide variety of north European catchments systems and provide an integrated and process-based understanding of base-line contamination of major catchments. The presented data highlight the findings from the PERSPEC project, which was possible under the umbrella of the European Commission's 6th Framework Programme project SNOWMAN (contract no ERAC-CT-2003-003219).

  7. Can the catchment scale SWAT model undertake management at field scale?

    NASA Astrophysics Data System (ADS)

    Lu, Shenglan; Trolle, Dennis; Blicher-Mathiesen, Gitte; Estrup Andersen, Hans

    2015-04-01

    Nitrate losses from agricultural areas to waterways remain a serious stressor for aquatic ecosystems in many developed countries, despite the fact that decades of water action plans have reduced these losses. More intelligent ways of further reducing nitrate losses are now sought for, particularly the ability to pinpoint the location of critical areas where the potential for nitrate losses are high. Here, mathematical models can play a key role, as they offer the ability to locate areas at various size-discretization, where losses could potentially be high. The Soil and Water Assessment Tool (SWAT) have been widely applied for quantifying nitrate losses from agricultural catchments, but the model have rarely be validated at field scale that are relevant for implementation of management measures, often due to lack of data from such scales. In this study, we calibrated the SWAT model for intensively monitored smaller Danish catchments based only on data from the catchment outlets. We then looked into smaller areas within these catchments and evaluated the SWAT models ability to reproduce observed tile drain dynamics and nitrogen budgets at the field scale, including fertilizer application, crop yields, leaching through the root zone and tile drainage. To evaluate the importance of the simulated tile drainage at larger scales, we applied the SWAT model to a large section of the River Odense catchment in Denmark and analysed the nitrogen sources and budgets.

  8. Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

    NASA Astrophysics Data System (ADS)

    Campbell, J. M.; Jordan, P.; Arnscheidt, J.

    2015-01-01

    This study reports the use of high-resolution water quality monitoring to assess the influence of changes in land use management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the issue of agricultural soil P management and subsequent diffuse transfers at high river flows over a 5-year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STSs) and mitigation efforts - a key concern for catchment management. Results showed an inconsistent response to soil P management over 5 years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STSs) and also to gauge their effectiveness.

  9. Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

    NASA Astrophysics Data System (ADS)

    Campbell, J. M.; Jordan, P.; Arnscheidt, J.

    2014-09-01

    This study reports the use of high resolution water quality monitoring to assess the influence of changes in landuse management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the "wicked problem" of agricultural soil P management and subsequent diffuse transfers at high river flows over a five year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STS) and mitigation efforts - here termed the "filthy issue" of rural catchment management. Results showed an inconsistent response to soil P management over five years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STS) and also to gauge their effectiveness.

  10. Disentangling the influence of hydroclimatic patterns and agricultural management on river nitrate dynamics from sub-hourly to decadal time scales.

    PubMed

    Dupas, Rémi; Jomaa, Seifeddine; Musolff, Andreas; Borchardt, Dietrich; Rode, Michael

    2016-11-15

    Despite extensive efforts to reduce nitrate transfer in agricultural areas, limited response is often observed in the nitrate concentration in rivers. To investigate the reasons for this limited response, nitrate dynamics in a 100km(2) agricultural catchment in eastern Germany was analysed from sub-hourly to decadal time-scales. Sub-hourly analysis of storm event dynamics during a typical hydrological year (2005-2006) was performed to identify periods of the year with high leaching risk and to link the latter to agricultural management practices in the catchment. Dynamic Harmonic Regression analysis of a 32-year (1982-2014) record of nitrate and discharge revealed that i) the long-term trend in nitrate concentration was closely related to that in discharge, suggesting that large-scale weather and climate patterns were masking the effect of improved nitrogen management on nitrate trends; ii) a persistent seasonal pattern with winter concentration maxima and summer minima could be observed, which was interpreted in terms of a dynamic nitrate concentration profile in the soil and subsoil; and iii) the catchment progressively changed from chemodynamic to more chemostatic behaviour over the three decades of study, which is a sign of long-term homogenisation of nitrate concentrations distribution over depth. This study shows that detailed physical understanding of nitrate dynamics across time scales can be obtained only through combined analysis of long-term records and high-resolution sensor data. Hence, a joint effort is advocated between environmental authorities, who usually perform long-term monitoring, and scientific programmes, which usually perform high-resolution monitoring. PMID:27422723

  11. A methodology to determine pesticides pollution sources in water catchments: study case (Belgium).

    PubMed

    Limbourg, Q; Noel, S; Huyghebaert, B; Capette, L; Hallet, V

    2009-01-01

    In the Walloon Region (Belgium), a Committee of Investigation was created in 2007 to investigate and determine the potential pesticides pollution sources in drinkable water catchments. This Committee, constituted by a multidisciplinary team of experts i.e agronomists, soil scientists, phyto-chemists, hydrogeologists, is coordinated by the Walloon Agricultural Research Centre (CRA-W) and funded by the Société Publique de Gestion des Eaux (SPGE). The diagnosis method is inspired of the AQUAPLAINE method (Arvalis, France), and is composed of four steps: 1/preparing the diagnosis using existing data, 2/diagnosis using data bank completed by field observations, 3/meeting and discussion with the pesticide users, 4/final diagnosis and remediation proposal. In a rural district of Walloon Region, a water producer who possesses two catchments ("Les marroniers" (P1) and "Puits N2" (P2)) has problems with pesticides. The pollution started in 1998 with atrazine and bromacile detected in the two catchments. In 2004, 2,6-dichlorobenzamide, metabolite of dichlobenil, was also detected in the catchments. At present, all these pesticides are still found in the catchment P1 and only the 2,6 dichlorobenzamide is found in the other catchment. These active ingredients are not used in agriculture expect atrazine. Indeed, the main user of these products is the public sector. An investigation was realised to locate the main sites which are treated with these pesticides in this commune. The conclusion of this study is that the local authority used dichlobenil, bromacile and atrazine to weed the public areas. In more, the filling and the cleaning areas of sprayer, used for the treatment, are located near the catchments. PMID:20218526

  12. Identifying critical source areas for phosphorus loss in Ireland using field and catchment scale ranking schemes

    NASA Astrophysics Data System (ADS)

    Hughes, K. J.; Magette, W. L.; Kurz, I.

    2005-03-01

    Phosphorus (P) in agricultural runoff is a major pollutant in many of Ireland's surface waters. Identification of areas that are at a high risk for P loss to surface waters is a critical component of river basin management. Two P ranking schemes (PRS's) were developed for Ireland, based on multi-criteria analysis approaches proposed in both the US and Europe, to predict the relative likelihood of P loss at both the field and catchment scales. The Field PRS was evaluated by comparing predicted rankings of potential P loss and transport against measured edge-of-field Dissolved Reactive P (DRP) loss for three fields with varying soil P levels. Qualitatively, results indicated that the Field PRS rankings corresponded to the magnitudes of measured P loss for the field sites, as well as to a reasoned evaluation of the relative likelihood that the fields would lose P that would subsequently make its way to surface water. The Catchment PRS was evaluated on a total of 31 catchments and sub-catchments by comparing predicted rankings of potential P loss and transport against measured in-stream median Molybdate Reactive P (MRP). Rankings of the relative likelihood of P loss and transport predicted by the Catchment PRS were positively correlated with median in-stream MRP ( r=0.51, P<0.05). Although the data available for these evaluations were limited, especially at field scale, and further research may identify the opportunity for modifications, both field and catchment scale P ranking schemes demonstrated a potential for identifying critical P source areas within catchments dominated by grass-based agricultural production systems, such as those in Ireland.

  13. A new method for separating tile drainage flow in a low land catchment using EMMA

    NASA Astrophysics Data System (ADS)

    Faber, Claas; Wu, Naicheng; Ulrich, Uta; Schmalz, Britta; Fohrer, Nicola

    2014-05-01

    Low land catchments are characterised by flat topography and low hydraulic gradients. Artificial drainages influence water and matter transport substantially in areas with agricultural usage. They shorten the soil passage and thus change the matter retention potential as well as runoff dynamics of the catchment. In such catchments, drainages and surface runoff constitute important entry pathways for nutrients into water bodies, especially after strong precipitation events. In order to be able to develop effective measures for the reduction of nutrient inflow, the main entry pathways for the important hydrological periods (low flow and rain events) haven to be known. The aim of the currently running, DFG funded project 'Separating surface runoff from tile drainage flow in agricultural lowland catchments based on diatoms to improve modeled runoff components and phosphorous transport' is to further investigate prevalent processes in this context in a 50 km2 low land catchment (Kielstau, Schleswig-Holstein, Germany) with the goal of improving existing models. The size and heterogeneity of the catchment do not allow a direct measurement of all flow components. Instead, naturally occurring chemical tracers are used to estimate the contribution of potential end members (surface runoff, drainage flow, soil water, ground water) to the total runoff (End Member Mixing Analysis). To this end, the end member are sampled regularly every 1-2 weeks and daily mixed samples as well as rain event based samples are taken at the catchment's outlet. In this project, diatoms are considered as biological tracers and are evaluated together with chemical tracers. Due to habitat preferences of certain species, indicator species for river- and drainage water could be determined. First results of the analyses are presented. Using the insights gained with this method, existing SWAT models for water quality and nutrient transport are further improved

  14. Catchment-scale herbicides transport: Theory and application

    NASA Astrophysics Data System (ADS)

    Bertuzzo, E.; Thomet, M.; Botter, G.; Rinaldo, A.

    2013-02-01

    This paper proposes and tests a model which couples the description of hydrologic flow and transport of herbicides at catchment scales. The model accounts for streamflow components' age to characterize short and long term fluctuations of herbicide flux concentrations in stream waters, whose peaks exceeding a toxic threshold are key to exposure risk of aquatic ecosystems. The model is based on a travel time formulation of transport embedding a source zone that describes near surface herbicide dynamics. To this aim we generalize a recently proposed scheme for the analytical derivation of travel time distributions to the case of solutes that can be partially taken up by transpiration and undergo chemical degradation. The framework developed is evaluated by comparing modeled hydrographs and atrazine chemographs with those measured in the Aabach agricultural catchment (Switzerland). The model proves reliable in defining complex transport features shaped by the interplay of long term processes, related to the persistence of solute components in soils, and short term dynamics related to storm inter-arrivals. The effects of stochasticity in rainfall patterns and application dates on concentrations and loads in runoff are assessed via Monte Carlo simulations, highlighting the crucial role played by the first rainfall event occurring after herbicide application. A probabilistic framework for critical determinants of exposure risk to aquatic communities is defined. Modeling of herbicides circulation at catchment scale thus emerges as essential tools for ecological risk assessment.

  15. A Catchment Systems Engineering (CSE) approach to managing intensively farmed land

    NASA Astrophysics Data System (ADS)

    Jonczyk, Jennine; Quinn, Paul; Barber, Nicholas; Wilkinson, Mark; ODonnell, Greg

    2014-05-01

    Rural land management practices can have a significant impact on the hydrological and nutrient dynamics within a catchment which can dramatically alter the way it processes water, exacerbating nutrient losses from the system. A collaborative and holistic approach for managing potential conflicts between land management activity for food production alongside the aspiration to achieve good water quality and the need to make space for water can ensure the long-term sustainability of our agricultural catchments. Catchment System Engineering (CSE) is an interventionist approach to altering the catchment scale runoff regime through the manipulation of hydrological flow pathways throughout the catchment. By targeting hydrological flow pathways at source, such as overland flow, field drain and ditch function, a significant component of the runoff generation can be managed, greatly reducing erosive soil losses. Coupled with management of farm nutrients at source many runoff attenuation features or measures can be co-located to achieve benefits for water quality. Examples of community-led mitigation measures using the CSE approach will be presented from two catchments in Northumberland, Northern England, that demonstrate the generic framework for identification of multipurpose features that slow, store and filter runoff at strategic locations in the landscape. Measures include within-field barriers, edge of field traps and within-field sediment filters and sediment traps which demonstrate how sediment can be trapped locally (including silt and clay fractions) and be recovered for use back on the land. Deliverables from this CSE approach includes the reduction of downstream flood risk and capturing of sediment and associated nutrients. The CSE approach allows for a more natural flood and nutrient management approach which helps to restore vital catchment functions to re-establish a healthy catchment system.

  16. The phosphorus content of fluvial suspended sediment in three lowland groundwater-dominated catchments

    NASA Astrophysics Data System (ADS)

    Ballantine, Deborah J.; Walling, Desmond E.; Collins, Adrian L.; Leeks, Graham J. L.

    2008-07-01

    SummaryThis paper reports an investigation of the phosphorus (P) content of fluvial suspended sediment samples collected from three lowland groundwater-dominated agricultural catchments in the UK. In-stream trap samplers were installed at a total of 21 locations in the catchments of the Rivers Frome and Piddle in Dorset and in the Upper Tern in Shropshire, UK. Time-integrated suspended sediment samples ( n = 187) were collected at regular intervals over a period of 22 months and analysed for total phosphorus (TP), inorganic phosphorus (IP), organic phosphorus (OP) and algal available phosphorus (AAP). TP concentrations varied between sampling sites in the Rivers Frome and Piddle, allowing key P inputs to be identified, while fractionation of P assisted in identifying the nature of these inputs. There was also significant variation in both the TP concentration and the concentration of individual fractions between the Frome and Piddle catchments and the Upper Tern. These contrasts were attributed to the differing underlying geologies, since the Frome and Piddle are underlain predominantly by chalk, whilst the Upper Tern is underlain by sandstone, and also to the different soil types present. The TP content of suspended sediment collected from the Frome catchment showed a statistically significant relationship with specific surface area, but this relationship was not found for the remaining catchments. Temporal variation in P concentrations at both the seasonal and event scale was also investigated. Seasonal variations were noted for TP concentrations and for the concentrations of IP, OP and AAP in all the study catchments, but no consistent seasonal patterns were discernible. Maximum and minimum concentrations of the individual fractions occurred during different months in each of the study catchments, suggesting that different controls operated in the individual catchments. Short-term temporal variations in TP concentrations were documented for two high flow events

  17. Projected Climate Change Impacts on a Mediterranean Catchment under Different Irrigation Scenarios

    NASA Astrophysics Data System (ADS)

    Gunten, D. V.; Wöhling, T.; Haslauer, C. P.; Cirpka, O. A.

    2014-12-01

    In semi-arid regions, irrigation is often needed for cultivation and greatly impacts the water cycle of agricultural catchments. It is important to investigate the effects of climate change in these settings under consideration of future agricultural management and irrigation needs. However, quantifying how irrigation influences climate-change effects is still a challenge. Understanding the differences in climate-change sensitivity between irrigated and non-irrigated catchments would allow refining regional-scale assessments of climate-change impacts. We investigated a catchment in north-east Spain which had not been irrigated prior to 2006 and where 54% of the land is now converted to irrigated agriculture. Data on hydraulic heads, discharge, and irrigation were used to simulate coupled surface-subsurface flow in the catchment, using the pde-based model HydroGeoSphere. The model performs well for both irrigated and non-irrigated periods. To predict future climate scenarios in the region, we use four regional climate models from the ENSEMBLE project (P.van der Linden and J.Mitchell, ENSEMBLES: Climate Change and its Impacts [...], Met Office Hadley Center, 2009) and three downscaling methods. We further investigated four irrigation scenarios, based on projected potential evapotranspiration. Preliminary results show a shift in the hydrological regime of the catchment under future climate scenarios. Under irrigation, the variability of low-flow discharge increases in future climate. On the contrary, peak flows increase and hydraulics heads decrease significantly in the non-irrigated scenarios. For example, annual maximum flow increases by about 15 % in the non-irrigated case but there is only little change in the corresponding irrigated scenarios. Sensitivity to projected precipitation changes is higher without irrigation, while potential evapotranspiration has more importance for irrigated catchments.

  18. Effects of climate and irrigation changes on the water balance of a Mediterranean catchment

    NASA Astrophysics Data System (ADS)

    von Gunten, Diane; Wöhling, Thomas; Haslauer, Claus; Cirpka, Olaf

    2015-04-01

    Climate change will strongly impact the water cycle of Mediterranean catchments as a result of the changes in precipitation patterns and increased temperature. However, effects of climate change are difficult to predict with precision and are often influenced by land-use or water management choices. In agricultural catchments, irrigation is of particular interest because of its importance for cultivation in semi-arid climate and because of its strong impacts on hydrological processes. Interactions between irrigation and climate change impacts are likely to be important and should be considered when studying the future of a catchment. However, they are still difficult to quantify. A better understanding of the differences in climate-change sensitivity between irrigated and non-irrigated catchments would allow a finer description of local climate change effects. In this study, we compared the impacts of climate change in various irrigation scenarios, including a scenario without irrigation. Our case study was a relatively small catchment (about 7.5km2) in north-east Spain, called the Lerma catchment. This catchment was not irrigated prior to 2006, but 54% of its surface is now used for irrigated agriculture. This transition to irrigated agriculture was closely monitored and data on hydraulic heads, discharge and daily irrigation volume are available. Based on these measurements, a coupled surface-subsurface model of the catchment was developed using the pde-based model HydroGeoSphere. The model performs well for both irrigated and non-irrigated periods. Future climate was predicted using four regional climate models from the ENSEMBLE project (P.van der Linden and J.Mitchell, ENSEMBLES: Climate Change and its Impacts [...], Met Office Hadley Center, 2009) and two downscaling methods, including one based on a weather generator. Four irrigation scenarios, based on projected potential evapotranspiration changes, were compared. Our results show a shift in the climate

  19. Nutrient water quality of the Wye catchment, UK: exploring patterns and fluxes using the Environment Agency data archives

    NASA Astrophysics Data System (ADS)

    Jarvie, H. P.; Neal, C.; Withers, P. J. A.; Robinson, A.; Salter, N.

    Water quality data, collected by the Environment Agency in England and Wales over 10 years (1991 - 2000) were used to examine the spatial distribution of nutrient pollution risk and for assessing broad-scale spatial and temporal variability in nutrient fluxes across the Wye catchment. Nutrient water quality across the upper and middle Wye catchment, and along the main River Wye, is generally very good. However, the main areas of concern lie in the small tributaries in the south and east of the catchment, which have lower dilution capacity and high agricultural and effluent inputs, and where mean Total Reactive Phosphorus (TRP) in some cases exceed 1 mg-P l-1. Indeed, mass load calculations have demonstrated that the lowland south and east portion of the catchment contributes more than 85% of the whole-catchment TRP and more than 78% of nitrate (NO3‾) loads. Ratios of NO3‾:Ca were used to fingerprint different water-types across the catchment, linked to weathering and agricultural activity. The Wye catchment has been subject to two major sets of perturbations during the study period: (i) climatic fluctuations, with a drought during 1995-6, followed by a subsequent drought-break in 1997/8, and extreme high river flows in the autumn/winter of 2000/2001, and (ii) introduction of tertiary P-treatment at major sewage treatment works in the catchment. The implications of these perturbations for the nutrient water quality of the Wye catchment are discussed. Recommendations are made for more targeted monitoring to directly assess diffuse source nutrient contributions.

  20. Storm-driven pesticide dynamics in a catchment system

    NASA Astrophysics Data System (ADS)

    Harrison, Rebecca; Freer, Jim; Michaelides, Katerina; Hurley, Steven; Howden, Nicholas; Bull, Ian

    2013-04-01

    Loss of pesticides from agricultural land in runoff and subsurface flow during rainfall events poses a significant concern for water quality, with adverse effects on drinking water and aquatic life. Pesticide mobilisation and transport is affected by runoff and erosion processes which leads to different flow pathways and pesticide residence times in a catchment. In the soil and sediment environment pesticides can be a significant component of surface water contamination because of their persistence in soil and sediment and that they have a tendency to desorb back into water over time. A lowland agricultural catchment upstream of a drinking-water supply reservoir in the South West of England is being used to investigate pesticide dynamics at the catchment scale during individual storm events. Pesticide concentration in water and suspended sediments were determined from samples taken at incremental changes in stream flow incorporating both rising and falling river levels. The study aims to determine the relative partitioning of pesticides transported in the dissolved phase or adsorbed to sediment. Analyses of soil, sediment and water from across the catchment aids understanding of the interaction between different media and can be used to determine the importance of dissolved and sediment-bound pesticide dynamics during individual storm events. Initial results imply that processes of transport and desorption are occurring in both soils and river and reservoir sediments which are likely to be an important factor for timing of pesticide movement. This suggests soil and sediment are acting as a sustained source of contamination to surface water. However; interactions between these different media are complex. Investigation of the molluscicide metaldehyde, showed this to be present in stream water at concentrations greater than 0.1 µg µl-1 nine months after application. Storm event analysis shows peak pesticide concentration in the stream to coincide with storm

  1. How tritium illuminates catchment structure

    NASA Astrophysics Data System (ADS)

    Stewart, M.; Morgenstern, U.; McDonnell, J.

    2012-04-01

    Streams contain water which has taken widely-varying times to pass through catchments, and the distribution of ages is likely to change with the flow. Part of the water has 'runoff' straight to the stream with little delay, other parts are more delayed and some has taken years (in some cases decades) to traverse the deeper regolith or bedrock of the catchment. This work aims to establish the significance of the last component, which is important because it can cause catchments to have long memories of contaminant inputs (e.g. nitrate). Results of tritium studies on streams world-wide were accessed from the scientific literature. Most of the studies assumed that there were just two age-components present in the streams (i.e. young and old). The mean ages and proportions of the components were found by fitting simulations to tritium data. It was found that the old component in streams was substantial (average was 50% of the annual runoff) and had considerable age (average mean age was 10 years) (Stewart et al., 2010). Use of oxygen-18 or chloride variations to estimate streamflow mean age usually does not reveal the age or size of this old component, because these methods cannot detect water older than about four years. Consequently, the use of tritium has shown that substantial parts of streamflow in headwater catchments are older than expected, and that deep groundwater plays an active and sometimes even a dominant role in runoff generation. Difficulties with interpretation of tritium in streams in recent years due to interference from tritium due to nuclear weapons testing are becoming less serious, because very accurate tritium measurements can be made and there is now little bomb-tritium remaining in the atmosphere. Mean ages can often be estimated from single tritium measurements in the Southern Hemisphere, because there was much less bomb-tritium in the atmosphere. This may also be possible for some locations in the Northern Hemisphere. Age determination on

  2. Hydrological variability and agricultural drainage ditch nutrient mitigation capacity: Inorganic nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The application of inorganic nitrogen fertilizers on agricultural landscapes has the potential to generate environmental degradation concerns at fine to coarse scales across the catchment and landscape. Inorganic nitrogen species (nitrate, nitrite, ammonia) are typically associated with subsurface f...

  3. A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

    NASA Astrophysics Data System (ADS)

    Maurer, T.; Schneider, A.; Gerke, H. H.

    2011-05-01

    Artificially-created hydrological catchments are characterized by sediment structures from technological construction processes that can potentially be important for modelling of flow and transport and for understanding initial soil and ecosystem development. The subsurface spatial structures of such catchments have not yet been sufficiently explored and described. Our objective was to develop a structure generator programme for modelling the 3-D spatial sediment distribution patterns depending on the technical earth-moving and deposition processes. For the development, the artificially-constructed hydrological catchment "Chicken Creek" located in Lower Lusatia, Germany, served as an example. The structure generator describes 3-D technological sediment distributions at two scales: (i) for a 2-D-vertical cross-section, texture and bulk density distributions are generated within individual spoil cones that result from mass dumping, particle segregation, and compaction and (ii) for the whole catchment area, the spoil cones are horizontally arranged along trajectories of mass dumping controlled by the belt stacker-machine relative to the catchment's clay layer topography. The generated 3-D texture and bulk density distributions are interpolated and visualized as a gridded 3-D-volume body using 3-D computer-aided design software. The generated subsurface sediment distribution for the Chicken Creek catchment was found to correspond to observed patterns although still without any calibration. Spatial aggregation and interpolation in the gridded volume body modified the generated distributions towards more uniform (unimodal) distributions and lower values of the standard deviations. After incorporating variations and pedotransfer approaches, generated sediment distributions can be used for deriving realizations of the 3-D hydraulic catchment structure.

  4. A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

    NASA Astrophysics Data System (ADS)

    Maurer, T.; Schneider, A.; Gerke, H. H.

    2011-12-01

    Artificially-created hydrological catchments are characterised by sediment structures from technological construction processes that can potentially be important for modelling of flow and transport and for understanding initial soil and ecosystem development. The subsurface spatial structures of such catchments have not yet been sufficiently explored and described. Our objective was to develop a structure generator programme for modelling the 3-D spatial distribution patterns of dumped sediments depending on the technical earth-moving and deposition processes. We are focussing in a first step on integrating sediment dumping, particle size, and bulk density modification processes on the catchment scale. For the model development, the artificially-constructed hydrological catchment "Chicken Creek" located in Lower Lusatia, Germany, served as an example. The structure generator describes 3-D technological sediment distributions at two scales: (i) for a 2-D-vertical cross-section, texture and bulk density distributions are generated within individual spoil cones that result from mass dumping, particle segregation, and compaction and (ii) for the whole catchment, the spoil cones are horizontally arranged along trajectories of mass dumping controlled by the belt stacker-machine relative to the catchment's clay layer topography. The generated 3-D texture and bulk density distributions are interpolated and visualised as a gridded 3-D-volume body using 3-D computer-aided design software. The generated subsurface sediment distribution for the Chicken Creek catchment was found to correspond to observed patterns already without calibration. Spatial aggregation and interpolation in the gridded volume body modified the generated distributions towards more uniform (unimodal) distributions and lower values of the standard deviations. The modelling approach is generally applicable to all situations where large masses of unconsolidated sediment are moved and dumped thereby allowing

  5. Upscaling Physics-based Models to Estimate Catchment Scale Effects of Localised Tree Planting

    NASA Astrophysics Data System (ADS)

    Ballard, C. E.; Bulygina, N.; McIntyre, N.; Wheater, H. S.

    2010-12-01

    Much of our knowledge about the changes in hydrology related to land use and land management is limited to the very small scale (e.g. changes in water retention properties, interception and runoff processes); however, we are generally most interested in the associated changes in flow regime at the catchment scale. A key methodological challenge is therefore how to upscale information about local scale changes. We present a model upscaling procedure that aims to quantify the changes in peak flows at multiple scales related to localised tree planting. The procedure divides the catchment into a number of hydrological response units, which are each classified based on soil types and land management. For each hydrological response unit, a physics-based model is developed, incorporating our understanding of hydrological processes and properties. The outputs from these physics-based models are used to train simpler “meta-models”, which are then incorporated into a semi-distributed catchment model. In this way, our understanding of local changes in physical properties can be incorporated into a more flexible and computationally efficient catchment scale conceptual model. This procedure previously performed well when supported by a multi-scale monitoring programme for a 12km2 catchment. The applicability of the procedure is now examined for a 260km2 catchment without supporting multi-scale monitoring. Without local data, physics-based models are developed a priori using information from the literature and qualitative field observations. We explore the significance of the uncertainties due to this lack of data and also uncertainties related to the upscaling procedure itself, particularly examining the identifiability of the predicted effects at multiple scales. Based on our findings we comment on the strengths and limitations of physics-based modelling and the upscaling procedure in terms of ability to predict catchment-scale impacts of local land management

  6. Comparing runoff on 11 poorly-gauged headwater catchments using a soft monitoring approach

    NASA Astrophysics Data System (ADS)

    Colin, F.; Crabit, A.; Moussa, R.

    2012-04-01

    Catchments in many parts of the world are either ungauged or poorly gauged, and the dominant processes governing their streamflow response are still poorly understood. The analysis of runoff coefficients provides essential insight into catchment response, particularly if both range of catchments and a range of events are compared. An original soft water level sensor is proposed to characterize rainfall and stream flows on agricultural catchments. This sensor works as a capacitor coupled with a capacitance to frequency converter and measures water level at an adjustable time step acquisition. It was designed to be handy, minimally invasive and optimised in terms of energy consumption and low-cost fabrication so as to multiply its use on several catchments under natural conditions. It was used as a stage recorder to measure water level dynamics in a channel during a runoff event and as a rain gauge to measure rainfall amount and intensity. Innovative work has been performed under controlled experimental conditions to estimate Manning's coefficient values for the different cover types observed in studied streams: non-aquatic vegetations (giant reed, bramble and thistle), grass and coarse granular deposits. The results show that estimates derived using roughness coefficients differ from those previously established for larger streams with aquatic vegetation. Based on these results, water discharge with a given uncertainty and hence runoff volume were estimated at the event and the annual scale. The sensor was tested under controlled conditions in the laboratory and under real conditions in the field. Comparisons of the sensor to reference devices (tipping bucket rain gauge, hydrostatic pressure transmitter limnimeter, Venturi channels, ...) showed accurate results: rainfall intensities and dynamic responses were accurately reproduced and discharges were estimated with an uncertainty usually acceptable in hydrology (Crabit et al., in Sensors 11, 2011). This device were

  7. A framework for managing runoff and pollution in the rural landscape using a Catchment Systems Engineering approach.

    PubMed

    Wilkinson, M E; Quinn, P F; Barber, N J; Jonczyk, J

    2014-01-15

    Intense farming plays a key role in increasing local scale runoff and erosion rates, resulting in water quality issues and flooding problems. There is potential for agricultural management to become a major part of improved strategies for controlling runoff. Here, a Catchment Systems Engineering (CSE) approach has been explored to solve the above problem. CSE is an interventionist approach to altering the catchment scale runoff regime through the manipulation of hydrological flow pathways throughout the catchment. By targeting hydrological flow pathways at source, such as overland flow, field drain and ditch function, a significant component of the runoff generation can be managed in turn reducing soil nutrient losses. The Belford catchment (5.7 km(2)) is a catchment scale study for which a CSE approach has been used to tackle a number of environmental issues. A variety of Runoff Attenuation Features (RAFs) have been implemented throughout the catchment to address diffuse pollution and flooding issues. The RAFs include bunds disconnecting flow pathways, diversion structures in ditches to spill and store high flows, large wood debris structure within the channel, and riparian zone management. Here a framework for applying a CSE approach to the catchment is shown in a step by step guide to implementing mitigation measures in the Belford Burn catchment. The framework is based around engagement with catchment stakeholders and uses evidence arising from field science. Using the framework, the flooding issue has been addressed at the catchment scale by altering the runoff regime. Initial findings suggest that RAFs have functioned as designed to reduce/attenuate runoff locally. However, evidence suggested that some RAFs needed modification and new RAFs be created to address diffuse pollution issues during storm events. Initial findings from these modified RAFs are showing improvements in sediment trapping capacities and reductions in phosphorus, nitrate and suspended

  8. Curricular Changes in Accredited Undergraduate Programmes in Argentina

    ERIC Educational Resources Information Center

    Coria, Maria Marta; Deluca, Monica; Martinez, Maria Eugenia

    2010-01-01

    This paper assesses the impact on the curricula of undergraduate programmes in Argentina of the quality assurance mechanism implemented by the National Commission for University Evaluation and Accreditation (CONEAU). The paper examines curricula changes in pharmacy, biochemistry and agriculture undergraduate programmes to show the major…

  9. Grassland agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture in grassland environments is facing multiple stresses from: shifting demographics, declining and fragmented agricultural landscapes, declining environmental quality, variable and changing climate, volatile and increasing energy costs, marginal economic returns, and globalization. Degrad...

  10. Agricultural Production.

    ERIC Educational Resources Information Center

    Lehigh County Area Vocational-Technical School, Schnecksville, PA.

    This brochure describes the philosophy and scope of a secondary-level course in agricultural production. Addressed in the individual units of the course are the following topics: careers in agriculture and agribusiness, animal science and livestock production, agronomy, agricultural mechanics, supervised occupational experience programs, and the…

  11. Catchment classification by means of hydrological models

    NASA Astrophysics Data System (ADS)

    Hellebrand, Hugo; Ley, Rita; Casper, Markus

    2013-04-01

    An important hydrological objective is catchment classification that will serve as a basis for the regionalisation of discharge parameters or model parameters. The main task of this study is the development and assessment of two classification approaches with respect to their efficiency in catchment classification. The study area in western Germany comprises about 80 catchments that range in size from 8 km2 up to 1500 km2, covering a wide range of geological substrata, soils, landscapes and mean annual precipitation. In a first approach Self Organising Maps (SOMs) use discharge characteristics or catchment characteristics to classify the catchments of the study area. Next, a reference hydrological model calibrates the catchments of the study area and tests the possibilities of parameter transfer. Compared to the transfer of parameters outside a class, for most catchments the model performance improves when parameters within a class are transferred. Thus, it should be possible to distinguish catchment classes by means of a hydrological model. The classification results of the SOM are compared to the classification results of the reference hydrological model in order to determine the latter validity. The second approach builds on the first approach in such a way that it uses the Superflex Modelling Framework instead of only one reference model. Within this framework multiple conceptual model structures can be calibrated and adapted. Input data for each calibration of a catchment are hourly time series of runoff, precipitation and evaporation for at least eight years. The calibration of multiple models for each catchment and their comparison allows for the assessment of the influence of different model structures on model performance. Learning loops analyse model performance and adapt model structures accordingly with a view to performance improvement. The result of the modelling exercise is a best performing model structure for each catchment that serves as a basis

  12. Assessing pesticide exposure of the aquatic environment in tropical catchments

    NASA Astrophysics Data System (ADS)

    Weiss, Frederik; Zurbrügg, Christian; Eggen, Rik; Castillo, Luisa; Ruepert, Clemens; Stamm, Christian

    2015-04-01

    Today, pesticides are intensively used in agriculture across the globe. Worldwide about 2.4×106 tons of pesticides are used annually on 1.6×109 ha of arable land. This yields a global average use of pesticides of 1.53 kg ha-1 year-1. Available data suggest that the use in the agricultural sector will continue to grow. Recently it was estimated that within the last decade, the world pesticide market increased by 93% and the Brazilian market alone by 190%. Though pesticides are intensively used in many low and middle income countries (LAMICs), scientifically sound data of amounts and types of pesticide use and the resulting impact on water quality are lacking in many of these countries. Therefore it is highly relevant to: i) identify risk areas where pesticides affect environmental health, ii) understand the environmental behavior of pesticides in vulnerable tropical ecosystems; and iii) develop possible mitigation options to reduce their exposure to ecosystems and humans. Here we present a project that will focus on assessing pesticide exposure of the aquatic environment and humans in tropical catchments of LAMICs. A catchment in the Zarcero province in Costa Rica will be the test case. Pesticide exposure will be assessed by passive sampling. In order to cover a broad range of compounds of possible use, two sampling devices will be used: SDB membranes for collecting polar compounds and silicon sheets for accumulating apolar pesticides. Extracts will be subsequently analysed by GC-MSMS and LC-HRMS.

  13. Agricultural drainage practices in Ireland

    NASA Astrophysics Data System (ADS)

    Ryan, T. D.

    1986-02-01

    Agricultural drainage practices are reviewed under two main headings: arterial drainage of river catch-ments by developing main channels, and field drainage of smaller parcels of land using pipes and open trenches. The use of cost/benefit analysis on the arterial drainage program is considered and the inherent errors are discussed. Conservation of the environment is described as it applies to land-scaping, fisheries, and wildlife, and the drainage authorities are shown to have an enlightened attitude to proper preservation of the world around us.

  14. Upscaling spatially heterogeneous parameterisations of soil compaction to investigate catchment scale flood risk.

    NASA Astrophysics Data System (ADS)

    Coates, Victoria; Pattison, Ian

    2016-04-01

    Upscaling land management signals observed at the point scale to the regional scale is challenging for three reasons. Individual catchments are unique and at the point scale land management signals are spatially and temporally variable, depending on topography, soil characteristics and on the individual characteristics of a rainfall event. However at larger scales land management effects diffuse and climatic or human induced signals have a larger impact. This does not mean that there is no influence on river flows, just that the effect is not discernible. Land management practices in different areas of the catchment vary spatially and temporally and their influence on the flood hydrograph will be different at different points within the catchment. Once the water enters the river, the land management effects are disturbed further by hydrodynamic and geomorphological dispersion. Pastoral agriculture is the dominant rural land cover in the UK (40% is classified as improved/ semi-natural grassland - Land Cover Map 2007). The intensification of agriculture has resulted in greater levels of soil compaction associated with higher stocking densities in fields. Natural flood management is the alteration, restoration or use of landscape features to reduce flood risk. Soil compaction has been shown to change the partitioning of rainfall into runoff. However the link between locally observed hydrological changes and catchment scale flood risk has not yet been proven. This paper presents the results of a hydrological modelling study on the impact of soil compaction on downstream flood risk. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK (area of 120km2) to determine soil characteristics and compaction levels under different types of land-use. We use this data to parameterise and validate the Distributed Physically-based Connectivity of Runoff model. A number of compaction scenarios have been tested that represent

  15. Hydropedological insights when considering catchment classification

    NASA Astrophysics Data System (ADS)

    Bouma, J.; Droogers, P.; Sonneveld, M. P. W.; Ritsema, C. J.; Hunink, J. E.; Immerzeel, W. W.; Kauffman, S.

    2011-06-01

    Soil classification systems are analysed to explore the potential of developing classification systems for catchments. Soil classifications are useful to create systematic order in the overwhelming quantity of different soils in the world and to extrapolate data available for a given soil type to soils elsewhere with identical classifications. This principle also applies to catchments. However, to be useful, soil classifications have to be based on permanent characteristics as formed by the soil forming factors over often very long periods of time. When defining permanent catchment characteristics, discharge data would therefore appear to be less suitable. But permanent soil characteristics do not necessarily match with characteristics and parameters needed for functional soil characterization focusing, for example, on catchment hydrology. Hydropedology has made contributions towards the required functional characterization of soils as is illustrated for three recent hydrological catchment studies. However, much still needs to be learned about the physical behaviour of anisotropic, heterogeneous soils with varying soil structures during the year and about spatial and temporal variability. The suggestion is made therefore to first focus on improving simulation of catchment hydrology, possibly incorporating hydropedological expertise, before embarking on a catchment classification effort which involves major input of time and involves the risk of distraction. In doing so, we suggest to also define other characteristics for catchment performance than the traditionally measured discharge rates. Such characteristics may well be derived from societal issues being studied, as is illustrated for the Green Water Credits program.

  16. Agricultural Waste.

    PubMed

    Xue, Ling; Zhang, Panpan; Shu, Huajie; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2016-10-01

    In recent years, the quantity of agricultural waste has been rising rapidly all over the world. As a result, the environmental problems and negative impacts of agricultural waste are drawn more and more attention. Therefore, there is a need to adopt proper approaches to reduce and reuse agricultural waste. This review presented about 200 literatures published in 2015 relating to the topic of agricultural waste. The review examined research on agricultural waste in 2015 from the following four aspects: the characterization, reuse, treatment, and management. Researchers highlighted the importance to reuse agricultural waste and investigated the potential to utilize it as biofertilizers, cultivation material, soil amendments, adsorbent, material, energy recycling, enzyme and catalyst etc. The treatment of agricultural waste included carbonization, biodegradation, composting hydrolysis and pyrolysis. Moreover, this review analyzed the differences of the research progress in 2015 from 2014. It may help to reveal the new findings and new trends in this field in 2015 comparing to 2014. PMID:27620093

  17. Transport of cyazofamid and kresoxim methyl in runoff at the plot and catchment scales

    NASA Astrophysics Data System (ADS)

    Lefrancq, Marie; Joaquín García Verdú, Antonio; Maillard, Elodie; Imfeld, Gwenaël; Payraudeau, Sylvain

    2013-04-01

    Surface runoff and erosion during the course of rainfall events represent major processes of pesticides transport from agricultural land to aquatic ecosystem. In general, field and catchment studies on pesticide transfer are carried out separately. A study at both scales may enable to improve the understanding of scale effects on processes involved in pesticides transport and to give clues on the source areas within an agricultural catchment. In this study, the transport in runoff of two widely used fungicides, i.e. kresoxim methyl (KM) and cyazofamid (CY) was assessed in a 43 ha vineyard catchment and the relative contribution of the total fungicides export from one representative plot was evaluated. During an entire period of fungicide application, from May to August 2011, the discharge and loads of dissolved and particle-laden KM and CY were monitored at the plot and catchment scales. The results showed larger export coefficient of KM and CY from catchment (0.064 and 0.041‰ for KM and CY respectively) than from the studied plot (0.009 and 0.023 ‰ for KM and CY respectively). It suggests that the plot margins especially the road network contributed as well to the fungicide loads. This result underlines the impact of fungicide drift on non-target areas. Furthermore, a larger rainfall threshold is necessary at the plot scale to trigger runoff and mobilise pesticides than on the road network. At the plot scale, a rapid dissipation of the both fungicides in the top soil was observed. It highlights that the risky period encompasses the first rainfall events triggering runoff after the applications. At both scales, KM and CY were not detected in suspended solids (i.e. > 0.7 µm). However their partitioning in runoff water differed. 64.1 and 91.8% of the KM load was detected in the dissolved phase (i.e. < 0.22 µm) at the plot and catchment scales respectively, whereas 98.7 and 100% of the CY load was detected in the particulate phase (i.e. between 0.22 and 0.7 µm

  18. Vocational Agriculture Education. Agricultural Mechanics.

    ERIC Educational Resources Information Center

    Smith, Eddie; And Others

    To assist teachers in agricultural mechanics in providing comprehensive instruction to their students, this curriculum guide treats both the mechanical skills and knowlege necessary for this specialized area. Six sections are included, as follow: orientation and safety; agricultural mechanics skills; agricultural power and machinery; agricultural…

  19. High-resolution monitoring of catchment nutrient response to the end of the 2011-2012 drought in England, captured by the demonstration test catchments

    NASA Astrophysics Data System (ADS)

    Outram, F. N.; Lloyd, C.; Jonczyk, J.; Benskin, C. McW. H.; Grant, F.; Dorling, S. R.; Steele, C. J.; Collins, A. L.; Freer, J.; Haygarth, P. M.; Hiscock, K. M.; Johnes, P. J.; Lovett, A. L.

    2013-12-01

    The Demonstration Test Catchments (DTC) project is a UK Government funded initiative to test the effectiveness of on-farm mitigation measures designed to reduce agricultural pollution without compromising farm productivity. Three distinct catchments in England have been chosen to test the efficacy of mitigation measures on working farms in small tributary sub-catchments equipped with continuous water quality monitoring stations. The Hampshire Avon in the south is a mixed livestock and arable farming catchment, the River Wensum in the east is a lowland catchment with predominantly arable farming and land use in the River Eden catchment in the north-west is predominantly livestock farming. One of the many strengths of the DTC as a national research platform is that it provides the ability to investigate catchment hydrology and biogeochemical response across different landscapes and geoclimatic characteristics, with a range of differing flow behaviours, geochemistries and nutrient chemistries. Although numerous authors present studies of individual catchment responses to storms, no studies exist of multiple catchment responses to the same rainfall event captured with in situ high-resolution nutrient monitoring at a national scale. This paper brings together findings from all three DTC research groups to compare the response of the catchments to a major storm event in April 2012. This was one of the first weather fronts to track across the country following a prolonged drought period affecting much of the UK through 2011-2012, marking an unusual meteorological transition when a rapid shift from drought to flood risk occurred. The effects of the weather front on discharge and water chemistry parameters, including nitrogen species (NO3-N and NH4-N) and phosphorus fractions (total P (TP) and total reactive P (TRP)), measured at a half-hourly time step are examined. When considered in the context of one hydrological year, flow and concentration duration curves reveal that

  20. Linking water quality trends with land use intensification in dairy farming catchments

    NASA Astrophysics Data System (ADS)

    Smith, Andrew P.; Western, Andrew W.; Hannah, Murray C.

    2013-01-01

    SummaryAgriculture, particularly pastoral based dairying, has intensified significantly in the past two decades. There are mounting concerns that this intensification could be linked to declining environmental quality. This paper analyses changes in water quality in three catchments in south-west Victoria, Australia, where the dominant land use has been dairying for the past 21 years and where the intensity of milk production has increased, driven by changes in farming systems and imports of nitrogen (N) and phosphorus (P) in various forms. We aimed to investigate if water quality has changed over that period and if such changes were related to the intensity of land use at the catchment scale. Three adjoining catchments were investigated which are different in terms of hydrology, biochemistry and land use proportions. Statistical analysis of continuous datasets showed that concentrations of N and P changed over the 21 year period. There were notable links between the intensification of milk production and increasing concentrations of N and P in streams from 1990 to 2000. The influence varied between catchments possibly due to hydrological differences that in turn influence biogeochemistry. From 2000 to 2011, there is some evidence this link may be starting to become decoupled due to various changes in farming systems, although it is difficult to specify which changes have had the greatest effect. The outcome of the close links between production intensification and water quality is that without fundamental changes to the farming systems, or without physical changes implemented in the catchment such as more effective riparian buffers or treatment wetlands, increases in agricultural intensity may lead to further degradation of water quality. Through this study the importance of investigating multiple water quality parameters and land use datasets to understand catchment functioning has been highlighted.

  1. Process type identification in torrential catchments

    NASA Astrophysics Data System (ADS)

    Heiser, Micha; Scheidl, Christian; Eisl, Julia; Spangl, Bernhard; Hübl, Johannes

    2015-04-01

    The classification of torrential processes takes place according to factors like sediment concentration and flow behavior and ranges from fluvial process types, including water floods and fluvial sediment transport processes, to fluvial mass movements such as debris flows. This study hypothises a context between basic geomorphological disposition parameters and potential dominant flow process types in steep headwater catchments. Thus, examined catchments were selected based on a historical event documentation of torrential events in the Austrian Alps. In total, 84 catchments could be analysed, and 11 different morphometric parameters were considered. To predict the dominant torrential process type within a catchment, a naive Bayes classifier, a decision tree model, and a multinomial regression model was trained against the compiled geomorphological disposition parameters. All models as well as their combination were compared, based on bootstrapping and complexity. The presented classification model with the lowest prediction error for our data might help to identify the most likely torrential process within a considered catchment.

  2. Tackling agricultural diffuse pollution: What might uptake of farmer-preferred measures deliver for emissions to water and air?

    PubMed

    Collins, A L; Zhang, Y S; Winter, M; Inman, A; Jones, J I; Johnes, P J; Cleasby, W; Vrain, E; Lovett, A; Noble, L

    2016-03-15

    Mitigation of agricultural diffuse pollution poses a significant policy challenge across Europe and particularly in the UK. Existing combined regulatory and voluntary approaches applied in the UK continue to fail to deliver the necessary environmental outcomes for a variety of reasons including failure to achieve high adoption rates. It is therefore logical to identify specific on-farm mitigation measures towards which farmers express positive attitudes for higher future uptake rates. Accordingly, a farmer attitudinal survey was undertaken during phase one of the Demonstration Test Catchment programme in England to understand those measures towards which surveyed farmers are most receptive to increasing implementation in the future. A total of 29 on-farm measures were shortlisted by this baseline farm survey. This shortlist comprised many low cost or cost-neutral measures suggesting that costs continue to represent a principal selection criterion for many farmers. The 29 measures were mapped onto relevant major farm types and input, assuming 95% uptake, to a national scale multi-pollutant modelling framework to predict the technically feasible impact on annual agricultural emissions to water and air, relative to business as usual. Simulated median emission reductions, relative to current practise, for water management catchments across England and Wales, were estimated to be in the order sediment (20%)>ammonia (16%)>total phosphorus (15%) ≫ nitrate/methane (11%)>nitrous oxide (7%). The corresponding median annual total cost of the modelled scenario to farmers was £3 ha(-1)yr(-1), with a corresponding range of -£84 ha(-1)yr(-1) (i.e. a net saving) to £33 ha(-1)yr(-1). The results suggest that those mitigation measures which surveyed farmers are most inclined to implement in the future would improve the environmental performance of agriculture in England and Wales at minimum to low cost per hectare. PMID:26789365

  3. Rainwater Harvesting in South India: Understanding Water Storage and Release Dynamics at Tank and Catchment Scales

    NASA Astrophysics Data System (ADS)

    Basu, N. B.; Van Meter, K. J.; Mclaughlin, D. L.; Steiff, M.

    2015-12-01

    Rainwater harvesting, the small-scale collection and storage of runoff for irrigated agriculture, is recognized as a sustainable strategy for ensuring food security, especially in monsoonal landscapes in the developing world. In south India, these strategies have been used for millennia to mitigate problems of water scarcity. However, in the past 100 years many traditional rainwater harvesting systems have fallen into disrepair due to increasing dependence on groundwater. With elevated declines in groundwater resources, there is increased effort at the state and national levels to revive older systems. Critical to the success of such efforts is an improved understanding of how these ancient water-provisioning systems function in contemporary landscapes with extensive groundwater pumping and shifted climatic regimes. Knowledge is especially lacking regarding the water-exchange dynamics of these rainwater harvesting "tanks" at tank and catchment scales, and how these exchanges regulate tank performance and catchment water balances. Here, we use fine-scale water level variations to quantify daily fluxes of groundwater, evapotranspiration, and sluice outflows in four tanks over the 2013 northeast monsoon season in a tank cascade that covers a catchment area of 28.2 km2. Our results indicate a distinct spatial pattern in groundwater-exchange dynamics, with the frequency and magnitude of groundwater inflow events (as opposed to outflow) increasing down the cascade of tanks. The presence of tanks in the landscape dramatically alters the catchment water balance, with catchment-scale runoff:rainfall ratios decreasing from 0.29 without tanks to 0.04 - 0.09 with tanks. Recharge:rainfall ratios increase in the presence of tanks, from ~0.17 in catchments without tanks to ~ 0.26 in catchments with tanks. Finally, our results demonstrate how more efficient management of sluice outflows can lead to the tanks meeting a higher fraction of crop water requirements.

  4. Impact of land-use on water pollution in a rapidly urbanizing catchment in China

    NASA Astrophysics Data System (ADS)

    Khu, Soon-Thiam; Qin, Huapeng

    2010-05-01

    Many catchments in developing countries are undergoing fast urbanization which is usually characterized by population increase, economic growth as well as drastic changes of land-use from natural/rural to urban area. During the urbanization process, some catchments experience water quality deterioration due to rapid increase of pollution loads. Nonpoint source pollution resulting from storm water runoff has been recognized as one of the major causes of pollutants in many cities in developing countries. The composition of land-use for a rapidly urbanizing catchment is usually heterogeneous, and this may result in significant spatial variations of storm runoff pollution and increase the difficulties of water quality management in the catchment. The Shiyan Reservoir catchment, a typical rapidly urbanizing area in China, is chosen as the study area, and temporary monitoring sites were set at the outlets of its 6 sub-catchments to synchronously measured rainfall, runoff and water quality during 4 storm events. Three indicators, event pollutant loads per unit area (EPL), event mean concentration (EMC) and pollutant loads transported by the first 50% of runoff volume (FF50), were used to describe the runoff pollution for different pollutants (such as COD, BOD, NH3-N, TN, TP and SS) in each sub-catchment during the storm events; and the correlations between runoff pollution spatial variations and land-use patterns were tested by Spearman's rank correlation analysis. The results indicated that similar spatial variation trends were found for different pollutants (EPL or EMC) in light storm events, which strongly correlate with the proportion of residential land-use; however, they have different trends in heavy storm events, which correlate with the different proportional combination of residential, industrial, agricultural and bare land-use. It is also shown that it is necessary to consider some pervious land-use types in runoff pollution monitoring or management for a

  5. Differentiating causes for erosion at the catchment scale: do soil conservation measures mitigate weather dynamics?

    NASA Astrophysics Data System (ADS)

    Barneveld, Robert; Greipsland, Inga

    2016-04-01

    The efficacy of most measures to control soil loss is well established at the field or plot scale. Less well documented are the changes in hydrological behaviour and sediment production at the scale of the (small) catchment. In Norway, incentives to reduce tillage have been in place for over decades. However, even long time (20 years) discharge monitoring of a series of small catchments does not show a clear effect of the application of conservation measures. This research hypothesizes that the effect of weather conditions for a 4.2 km2 catchment in southeastern Norway outweighs the effect of conservation measures in the time series on runoff and sediment load. To test this, it was assumed that trends and changes in soil loss E over time are the product of an agromic index C, precipitation P and rainfall erosivity R. The values of C were calculated based on extensive farm records, covering every tillage operation for every field in the catchment for the period of investigation. Runoff and sediment load records were used to parameterise and test different correlative models. In order to quantify the effect of topography on the degree to which conservations measures reduce soil loss at catchment level, a spatially distributed connectivity index was calculated and multiplied with C. Calculations were carried out for a 10 year period, in monthly time steps. The following statistical models proved the most promising to correlate sediment load to precipitation and agronomic practice. Et=a \\cdot Ptb \\cdot Pt-1c \\cdot Ctd Et=a \\cdot Rtb \\cdot Pt-1c \\cdot Ctd where Pt-1c, the precipition in the prior month, is a proxy indicator for antecedent moisture conditions. The results show that precipitation dynamics outweigh the effect of soil conservation measures for this typical agricultural catchment. It also shows that the inclusion of a hydrological connectivity index improves the quantification of the effect of soil conservation measures on the catchment scale.

  6. Collaborative knowledge in catchment research networks

    NASA Astrophysics Data System (ADS)

    Macleod, Christopher Kit

    2015-04-01

    There is a need to improve the production, sharing and use of collaborative knowledge of catchment systems through networks of researchers, policy makers and practitioners. This requires greater levels of systems based integrative research. In parallel to the growing realization that greater levels of collaborative knowledge in scientific research networks are required, a digital revolution has been taking place. This has been driven primarily by the emergence of distributed networks of computers and standards-based interoperability. The objective of this paper is to present the status and research needs for greater levels of systems based integrative research for the production, sharing and use of collaborative knowledge in catchment research networks. To enable increased levels of integrative research depends on development and application of digital technologies to improve collection, use and sharing of data and devise new knowledge infrastructures. This paper focuses on the requirements for catchment observatories that integrate existing and novel physical, social and digital networks of knowledge infrastructures. To support this focus, I present three leading international examples of collaborative networks of catchment researchers and their development of catchment observatories. In particular, the digital infrastructures they have developed to support collaborative knowledge in catchment research networks. These examples are from North America (NSF funded CUAHSI HIS) and from Europe (UK NERC funded EVOp and the German Helmholtz Association Centers funded TERENO/TEODOOR). These exemplars all supported advancing collaborative knowledge in catchment research networks through the development of catchment observatories. I will conclude by discussing the future research directions required for greater levels of production, sharing and use of collaborative knowledge in catchment research networks based on catchment systems science.

  7. Natural flood risk management in flashy headwater catchments: managing runoff peaks, timing, water quality and sediment regimes

    NASA Astrophysics Data System (ADS)

    Wilkinson, Mark; Addy, Steve; Ghimire, Sohan; Kenyon, Wendy; Nicholson, Alex; Quinn, Paul; Stutter, Marc; Watson, Helen

    2013-04-01

    Over the past decade many European catchments have experienced an unusually high number of flood events. A large number of these events are the result of intense rainfall in small headwater catchments which are dominated by surface runoff generation, resulting in flash flooding of local communities. Soil erosion and related water quality issues, among others, are typically associated with such rapid runoff generation. The hazard of flooding is increasing owing to impacts of changing climatic patterns (including more intense summer storms), intensification of agriculture within rural catchments and continued pressure to build on floodplains. Concurrently, the cost of constructing and maintaining traditional flood defences in small communities outweigh the potential benefits. Hence, there is a growing interest in more cost effective natural approaches that also have multipurpose benefits in terms of sediment, water quality, and habitat creation. Many catchments in Europe are intensively farmed and there is great potential for agriculture to be part of the solution to flood risk management. Natural flood management (NFM) is the alteration, restoration or use of landscape features with the aim of reducing flood risk by slowing down, storing (and filtering) rapid surface runoff. NFM includes measures such as temporarily storing water in ponds/wetlands, increasing soil infiltration, planting trees on floodplains and within catchments, re-meandering and wood placements in streams/ditches. In this presentation we highlight case studies from densely instrumented research sites across the UK (which could be typical of many European catchments) where NFM measures have been installed in small scale flashy catchments. The presentation will give an overview of the function of these measures in these catchments and how other multiple benefits are being accrued. Study catchments include the headwater catchments of the Bowmont (3 to 8 km2) and Belford Burn (6 km2) catchments. These

  8. Vulnerability of schools to floods in Nyando River catchment, Kenya.

    PubMed

    Ochola, Samuel O; Eitel, Bernhard; Olago, Daniel O

    2010-07-01

    This paper assesses the vulnerability of schools to floods in the Nyando River catchment (3,600 km(2)) in western Kenya and identifies measures needed to reduce this vulnerability. It surveys 130 schools in the lower reaches, where flooding is a recurrent phenomenon. Of the primary schools assessed, 40% were vulnerable, 48% were marginally vulnerable and 12% were not vulnerable. Of the secondary schools, 8% were vulnerable, 73% were marginally vulnerable and 19% were not vulnerable. Vulnerability to floods is due to a lack of funds, poor building standards, local topography, soil types and inadequate drainage. The Constituencies Development Fund (CDF), established in 2003, provides financial support to cover school construction and reconstruction costs; CDF Committees are expected to adopt school building standards. In an effort to promote safe and resilient construction and retrofitting to withstand floods, this paper presents vulnerability reduction strategies and recommendations for incorporating minimum standards in the on-going Primary School Infrastructure Programme Design. PMID:20298261

  9. Linking the field to the stream: soil erosion and sediment yield in a rural catchment, NW Spain

    NASA Astrophysics Data System (ADS)

    Rodriguez-Blanco, M. L.; Taboada-Castro, M. M.; Palleiro-Suarez, L.; Taboada-Castro, M. T.

    2009-04-01

    Quantifying the linkages between field erosion, fluvial response and catchment sediment yield remains problematic, among other reasons, because of the re-deposition of eroded sediment within the catchment, which is controlled by the spatial organization of the land use and the connectivity between sediment sources and the stream network. This paper presents the results of an integrated study that considered the relationship between erosion and stream sediment yield in an agroforestry catchment (16 km2) in NW Spain. The geology consists of basic metamorphic schist. The relieve of the area is steeper, the mean slope is approximately 19%. Main soil types are classified as Umbrisol and Cambisol. Soils are acidic and rich in organic matter. The soil texture is silt and silt-loam. Land cover consists of a mixture of forest (65%) and agricultural fields (mainly grassland, pasture and maize). The study combined measurements of soil erosion by concentrate flow and sediment deposition at field scale with sediment yield measured at the catchment outlet. The hydrological data and water samples were obtained at the catchment outlet. Stream water level was monitored continuously and converted to discharge using a rating curve. The sampling for suspended sediments was supplemented by an automatic sampler. Suspended sediment load was calculated from the suspended sediment concentrations and discharge data. Eroded volume was calculated from cross-sections (measured at specific points, where the section changed abruptly) and length of the channel segments. The total sediment delivered to stream was determined as the difference between all erosion features (rills and gullies) and the sediment volumes that were deposited on the fields. The results showed that in the catchment during the period winter 2007/08 soil erosion by concentrate flow, i.e. rills and ephemeral gullies, occurred on unprotected crop field. Erosion by concentrate flow was highly discontinuous within the catchment

  10. Predominant Runoff Components During Heavy Rainfall Events on Cultivated Catchment

    NASA Astrophysics Data System (ADS)

    Jeřábek, J.; Zumr, D.; Strouhal, L.

    2015-12-01

    The fact that flash floods initiated in arable catchments are often accompanied by massive sediment and nutrient loads often leads to the assumption that surface runoff is the principle pathway by which runoff reaches watercourses. But the hydrology of cultivated catchments has its specific features due to the temporary variable topsoil properties and a sharp divide between topsoil and compacted subsoil. Under various conditions the prevailing runoff mechanisms may vary from surface runoff to subsurface runoff or deep percolation. On the basis of an evaluation of several rainfall-runoff events in a representative agricultural catchment (Nucice, Czech Republic), we show that runoff from cultivated land may be generated in a way similar to that seen on forested slopes, where shallow subsurface runoff is the predominant pathway. To identify the predominant runoff pathway, we employed a combination of turbidity measurements and stream discharge data. Although we observed temporal variability of topsoil properties attributable to seasonal weather changes and agricultural activities, e.g. bulk density and porosity, runoff generation was mainly driven by precipitation characteristics and the initial catchment saturation. The concept of the runoff formation was also observed during plot scale experiments with rainfall simulator. Various initial soil moisture conditions, and vegetation stages delimited the simulations. Variable proportions of both monitored runoff components were observed in relation to rainfall intensity and duration, ranging from zero surface runoff to a distinct dominance of surface runoff. Even with the highest tested precipitation intensities, surface runoff always formed due to saturation excess of the topsoil, irrespective of the topsoil properties and crops. The experiments were numerically modelled and analysed to understand the effect of temporal variability in the macropores and intra-aggregate voids ratio within the topsoil. We used a

  11. A mediated modelling approach to promote collaborative learning in Andean rural micro-catchments in Colombia

    NASA Astrophysics Data System (ADS)

    Gowing, John; Dominguez, Isabel

    2013-04-01

    In rural catchments of developing countries water-related diseases, due to land use patterns (agriculture and livestock), microbial pollution, inadequate sanitation systems, access to water of poor quality, and lack of institutional support are common problems which disproportionally affect poor and vulnerable people. This research aims at developing a system dynamic model to improve the understanding of the macro and micro factors that influence human health and environmental health in rural micro-catchments in Valle del Cauca, Colombia. In this catchment livelihoods for most people depend on agriculture, particularly coffee. The research uses a mediated modeling approach, in which different stakeholders in modeling sessions, develop a STELLA model that allows them to identify relations between the economic, social and environmental factors and driving forces over the performance of their system. Stakeholders jointly develop the model structure in sessions facilitated by the researcher and the data required is gathered using secondary information from the different relevant institutions and primary information from field surveys that cover socioeconomic and environmental aspects that has not been previously collected by any institution or organization (i.e. household survey, stream water survey, and drinking water survey). Representation and understanding of their system will allow the stakeholders to test the effect of different management strategies in the micro-catchment and their associated socioeconomic, environmental and human health outcomes.

  12. Dominant controls on pesticide transport from tile to catchment scale: Lessons from a minimalist model

    NASA Astrophysics Data System (ADS)

    Zanardo, S.; Basu, N. B.; Botter, G.; Rinaldo, A.; Rao, P. S. C.

    2012-04-01

    This paper proposes a minimalist modeling approach for characterizing pesticide concentrations in runoff from agricultural catchments across spatial scales. The model proposed is of an intermediate level of complexity between traditional chromatographic separation models and the more complex dual-domain models. Parsimony in the model is achieved by assuming stationarity of catchment travel time distributions and by coupling a dual-domain source zone model that describes near-surface pesticide dynamics with the mass response function (MRF) approach, which describes catchment-scale solute transport. The model is evaluated by comparing predicted atrazine concentrations with measured values over a 5 yr period at two spatial scales (tile drain: 3-5 ha; river station: 69 km2) within an intensively managed agricultural catchment in Illinois, United States. Pesticide dynamics within the source zone provided the strongest control on leaching. Two parameters were calibrated at the tile scale, Γ, which describes partitioning in the dual-domain surficial source zone, and ke, which describes the mass transfer rate constant between the two domains. The initial peak of concentration was found to be sensitive to Γ, while the later peaks were sensitive to ke. The calibrated parameters at the tile stations were used to predict atrazine dynamics at the river station. Prediction errors are examined and related to the lack of detailed information about anthropogenic forcings across scales (e.g., land-use or soil/crop management practices).

  13. Effect of catchment characteristics on aquatic carbon export from a boreal catchment and its importance in regional carbon cycling.

    PubMed

    Huotari, Jussi; Nykänen, Hannu; Forsius, Martin; Arvola, Lauri

    2013-12-01

    Inland waters transport and emit into the atmosphere large amounts of carbon (C), which originates from terrestrial ecosystems. The effect of land cover and land-use practises on C export from terrestrial ecosystems to inland waters is not fully understood, especially in heterogeneous landscapes under human influence. We sampled for dissolved C species in five tributaries with well-determined subcatchments (total size 174.5 km(2)), as well as in various points of two of the subcatchments draining to a boreal lake in southern Finland over a full year. Our aim was to find out how land cover and land-use affect C export from the catchments, as well as CH4 and CO2 concentrations of the streams, and if the origin of C in stream water can be determined from proxies for quality of dissolved organic matter (DOM). We further estimated the gas evasion from stream surfaces and the role of aquatic fluxes in regional C cycling. The export rate of C from the terrestrial system through an aquatic conduit was 19.3 g C m(-2) (catchment) yr(-1), which corresponds to 19% of the estimated terrestrial net ecosystem exchange of the catchment. Most of the C load to the recipient lake consisted of dissolved organic carbon (DOC, 6.1 ± 1.0 g C m(-2) yr(-1)); the share of dissolved inorganic carbon (DIC) was much smaller (1.0 ± 0.2 g C m(-2) yr(-1)). CO2 and CH4 emissions from stream and ditch surfaces were 7.0 ± 2.4 g C m(-2) yr(-1) and 0.1 ± 0.04 g C m(-2) yr(-1), respectively, C emissions being thus equal with C load to the lake. The proportion of peatland in the catchment and the drainage density of peatland increased DOC in streams, whereas the proportion of agricultural land in the catchment decreased it. The opposite was true for DIC. Drained peatlands were an important CH4 source for streams. PMID:23893508

  14. Agriculture, summary

    NASA Technical Reports Server (NTRS)

    Baldwin, R.

    1975-01-01

    Applications of remotely sensed data in agriculture are enumerated. These include: predictions of forage for range animal consumption, forest management, soil mapping, and crop inventory and management.

  15. Doing hydrology backwards in tropical humid catchments

    NASA Astrophysics Data System (ADS)

    Real Rangel, R.; Brena-Naranjo, J. A.; Pedrozo-Acuña, A.

    2015-12-01

    Top-down approaches in hydrology offer the possibility to predict water fluxes at the catchment scale based on the interpretation of the observed hydrological response at the catchment itself. Doing hydrology backwards (inferring precipitation and evapotranspiration rates at the catchment scale from streamflow measurements, see Kirchner (2009)) can be a useful methodology for estimating water fluxes at the catchment and regional scales. Previous studies using this inverse modeling approach have been performed in regions (UK, Switzerland, France, Eastern US) where energy-limited (in winter and early spring) and water-limited conditions (in summer) prevail during a large period of the year. However, such approach has not been tested in regions characterized by a quasi-constant supply of water and energy (e.g. humid tropics). The objective of this work is to infer annual rates of precipitation and evapotranspiration over the last decade in 10 catchments located in Mexico's tropical humid regions. Hourly discharge measurements during recession periods were analyzed and parameters for the nonlinear storage-discharge relationship of each catchment were derived. Results showed large variability in both catchment-scale precipitation and evapotranspiration rates among the selected study sites. Finally, a comparison was done between such estimates and those obtained from remotely-sensed data (TRMM for precipitation and MOD16 for evapotranspiration).

  16. Catchment water storage: Models vs Measurements

    NASA Astrophysics Data System (ADS)

    McMillan, Hilary

    2016-04-01

    Recent years have seen a great deal of progress in development of hydrological models that can simulate both the dynamic streamflow response and the hydrochemical flux response of a catchment. In general terms, streamflow response is driven by water deficit in the catchment, whereas hydrochemical response is driven by water storage. Therefore, models that can simultaneously predict both responses must succeed in representing these two related, but different, quantities. This presentation will consider how much information we can gain from field studies to quantify the joint deficit/storage state of a catchment. In particular, examples from two New Zealand experimental catchments in lowland and high country locations will be used to link typical measurements available with the information required by hydrological - hydrochemical models. I will then use the example catchments to assess how well the structure of a typical hydrological-hydrochemical model is supported by field measurements. In particular, can we quantify catchment storage and link this to flow response? Can we incorporate our knowledge of plant water use into such a model, including timing and depth of water withdrawn by the plant? What can field measurements tell us about spatial variability in hydrological-hydrochemical response and can this be represented in the model? I will conclude by discussing what we can learn from field data about the major challenges ahead in catchment storage modelling.

  17. Impact of land use in catchment and human activities on water, sediment and vegetation of Mediterranean temporary pools.

    PubMed

    Rhazi, L; Grillas, P; Toure, A M; Ham, L T

    2001-02-01

    The vegetation and physical and chemical characteristics of the water and sediment in ten temporary pools submitted to various anthropogenic disturbance were studied in Morocco over two hydrological cycles (1997-1998 and 1998-1999). Results of multivariate and parametric analyses show that disturbance has a significant impact on water and sediment. Agriculture in the catchment resulted in higher levels of N and the use of detergent to higher levels of phosphorus in both water and sediment. Mineral extraction resulted in higher depth and longer duration of flooding. Vegetation characteristics were better correlated to hydrology (water depth, duration of flooding) than to nutrient variables. These results suggest that although agriculture in the catchment contribute in modifying the sediment characteristics, the impact on vegetation and its conservation value is limited. However, care should be taken of the long-term effects of agriculture through cumulative effects and of the possible consequences of changing the agricultural practices. PMID:11280049

  18. Transport of particle-associated elements in two agriculture-dominated boreal river systems.

    PubMed

    Marttila, Hannu; Saarinen, Tuomas; Celebi, Ahmet; Kløve, Bjørn

    2013-09-01

    Transport of particulate pollutants in fluvial systems can contribute greatly to total loads. Understanding transport mechanics under different hydrological conditions is key in successful load estimation. This study analysed trace elements and physico-chemical parameters in time-integrated suspended sediment samples, together with dissolved and total concentrations of pollutants, along two agriculture- and peatland-dominated boreal river systems. The samples were taken in a spatially and temporally comprehensive sampling programme during the ice-free seasons of 2010 and 2011. The hydrochemistry and transport of particle-bound elements in the rivers were strongly linked to intense land use and acid sulphate soils in the catchment area, with arable, pasture and peat areas in particular being main diffuse sources. There were significant seasonal and temporal variations in dissolved and particulate fluxes, but spatial variations were small. Continuous measurements of EC, turbidity and discharge proved to be an accurate indicator of dissolved and particulate fluxes. Overall, the results show that transport of particle-bound elements makes a major contribution to total transport fluxes in agriculture-dominated boreal rivers. PMID:23770550

  19. Agricultural Wastes.

    ERIC Educational Resources Information Center

    Jewell, W. J.; Switzenbaum, M. S.

    1978-01-01

    Presents a literature review of agricultural wastes, covering publications of 1976-77. Some of the areas covered are: (1) water characteristics and impacts; (2) waste treatment; (3) reuse of agricultural wastes; and (4) nonpoint pollution sources. A list of 150 references is also presented. (HM)

  20. VOCATIONAL AGRICULTURE.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Research Coordinating Unit.

    TO ASSIST THOSE WHO MAKE DECISIONS RELATING TO EDUCATIONAL PROGRAMS IN AGRICULTURE, RECENT RESEARCH IN VOCATIONAL AGRICULTURE IS SUMMARIZED. A 1963 STUDY TREATS THE RELATIONSHIP BETWEEN WORK EXPERIENCE AND STUDENT CHARACTERISTICS, PLANS, AND ASPIRATIONS. STUDIES ON POST-SECONDARY EDUCATION CONCERN GUIDELINES FOR TECHNICIAN PROGRAMS, JUSTIFICATION…

  1. Pseudo Paired Catchments Analysis to Assess the Impact of Urbanization on Catchment Hydrology

    NASA Astrophysics Data System (ADS)

    Salavati, B.; Oudin, L.; Furusho, C.; Ribstein, P.

    2014-12-01

    Paired catchments analysis provides a robust approach to assess the impact of land use changes on catchment's hydrological response. This approach is limited by the availability of data for two neighbor catchments with and without land use changes under similar climate conditions. Thus, hydrological modelling approaches are also very popular since they do not depend on data of a reference catchment. In the present study, 70 urbanized and non-urbanized paired catchments were selected in the United States. Unit housing density maps over the 1940-2010 time period were used to reconstruct historic impervious area extents with aproximatly the same resolution as the National Land Cover Database (NLCD) maps. Two approaches were compared to assess the impact of urbanization on catchment-scale hydrology: the classical paired catchments approach using observed flow time series and an alternative paired catchments approach involving hydrological modeling that allows to simulate a virtual control catchment. To this aim, the GR4J model, a conceptual daily 4-parameter hydrological model, was used. The parameters of the model calibrated on the pre urbanization period were used to predict the streamflow that would have occurred in the urban catchment if the urbanization had not taken place. Then, classical statistical methods involving ANCOVA were used to detect the significance and to quantify the change on the hydrological responses due to land use changes. Results show that the two approaches lead to similar conclusions on the impact of urbanization on catchment hydrology. Thus, the modelling approach provides a relevant alternative for case studies where data of reference catchments are not available.

  2. Collaborative Catchment-Scale Water Quality Management using Integrated Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Zia, Huma; Harris, Nick; Merrett, Geoff

    2013-04-01

    Electronics and Computer Science, University of Southampton, United Kingdom Summary The challenge of improving water quality (WQ) is a growing global concern [1]. Poor WQ is mainly attributed to poor water management and outdated agricultural activities. We propose that collaborative sensor networks spread across an entire catchment can allow cooperation among individual activities for integrated WQ monitoring and management. We show that sharing information on critical parameters among networks of water bodies and farms can enable identification and quantification of the contaminant sources, enabling better decision making for agricultural practices and thereby reducing contaminants fluxes. Motivation and results Nutrient losses from land to water have accelerated due to agricultural and urban pursuits [2]. In many cases, the application of fertiliser can be reduced by 30-50% without any loss of yield [3]. Thus information about nutrient levels and trends around the farm can improve agricultural practices and thereby reduce water contamination. The use of sensor networks for monitoring WQ in a catchment is in its infancy, but more applications are being tested [4]. However, these are focussed on local requirements and are mostly limited to water bodies. They have yet to explore the use of this technology for catchment-scale monitoring and management decisions, in an autonomous and dynamic manner. For effective and integrated WQ management, we propose a system that utilises local monitoring networks across a catchment, with provision for collaborative information sharing. This system of networks shares information about critical events, such as rain or flooding. Higher-level applications make use of this information to inform decisions about nutrient management, improving the quality of monitoring through the provision of richer datasets of catchment information to local networks. In the full paper, we present example scenarios and analyse how the benefits of

  3. Spatially distributed lateral nitrate transport at the catchment scale

    NASA Astrophysics Data System (ADS)

    Rode, M.; Franko, U.; Hesser, F.

    2010-12-01

    In river catchments, nitrogen transformation and storage processes during lateral transport are important in controlling nitrogen loads of surface waters. There is a lack of approaches which capture lateral flows and associated nitrogen transformation in a spatially distributed way. The aim of this paper is to develop a new conceptual nitrogen transport and transformation model which simulates the lateral nitrate transport in subsurface flow from the source area to the receiving water body. The developed tool is based on the Object Modelling System (OMS) framework and consists of the analytical spatially distributed hydrological model J2000, the nitrate recharge model Meta Candy and a new groundwater nitrogen routing component. The nitrogen subsurface transport component uses a variable number of sub storage layers for each hydrological response unit. Nitrate degradation in groundwater is calculated stoichiometrically according to a predefined amount on oxidizable substrate (pyrite and sedimentary organic matter) depending on the rock type. The decrease of subsurface nitrate reduction capacity can be simulated both spatially and over time. The new modelling approach was tested in a small agricultural lower mountain range catchment of Thuringia, Germany. The calibration of the nitrogen model using a four year period showed reasonable results for nitrate load calculations with a Nash and Sutcliff coefficient of 0.78. The three year validation period produced NS values of 0.75. There was a clear relationship of the goodness-of-fit between the hydrological simulations and the nitrate concentration calculations. Due to short residence times of the interflow nitrate degradation was restricted to slow base flow components. The new approach can be used to target nitrogen source areas within a catchment and assess the impact of these source areas on the nitrogen load of surface waters in a spatially distributed manner.

  4. Combining caesium-137 measurements and suspended sediment load data to investigate the sediment response of a small catchment in southern Italy

    NASA Astrophysics Data System (ADS)

    Porto, P.; Walling, D. E.; La Spada, C.; Mallimo, N.

    2015-03-01

    A long-term measurement programme was operated in southern Italy during the 1960s and 1970s, to provide information on the suspended sediment yields from the main river basins. Information obtained for the rivers of Calabria suggests that suspended sediment yields in this area are relatively low. However, there is evidence that the intensity of land degradation within the upstream catchments is substantially higher than suggested by the values of specific sediment yield and there is a need to explore the relationship between on-site soil loss and downstream sediment yield more closely. Monitoring time-integrated erosion rates over large areas has traditionally required extensive long-term measurement programmes employing experimental plots. The fallout radionuclide caesium-137 (137Cs) offers an alternative means of documenting medium-term rates of soil loss. This paper describes the use of 137Cs measurements and the available sediment load data to explore the links between soil erosion, sediment redistribution and storage, and sediment output for a medium-scale (41.3 km2) catchment in Calabria. Data available from a sediment load monitoring programme undertaken at the catchment outlet during 1962-1977 have been used to estimate the longer-term catchment sediment yield. This estimate has been combined with information provided by the 137Cs measurements, to establish a medium-term sediment budget for the catchment. The results provided by the 137Cs measurements indicate that the catchment is subject to much higher rates of soil loss and land degradation than suggested by its specific sediment yield. These findings are consistent with the results obtained for other catchments in Calabria for which both 137Cs derived erosion rates and measured sediment yields are available.

  5. Nutrient Losses from Row Crop Agriculture in Indiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient losses from agriculture in the Midwestern United States have been identified as contributing to water quality problems such as hypoxia in the Gulf of Mexico, and eutrophication in the great lakes. Fields and catchments in the Cedar Creek sub-watershed of the St. Joseph River basin were mon...

  6. Nutrient Losses from Row Crop Agriculture in Indiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Topic: USDA CEAP: Research Results and Recommendations Nutrient losses from row crop agriculture are known to contribute to water quality problems such as eutrophication and the zone of hypoxia in the Gulf of Mexico. Fields and catchments in the Cedar Creek sub-watershed of the St. Joseph River ba...

  7. Spectral Analysis in Catchment Hydrology and Geochemistry

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.; Feng, X.; Renshaw, C. E.; Neal, C.

    2001-12-01

    Spectral analysis of chemical tracer time series can be used to probe the internal workings of catchments. It has recently been shown that catchments act as fractal filters for inert chemical tracers like chloride, converting "white noise" rainfall chemistry inputs into fractal "1/f noise" runoff chemistry time series (Kirchner et al., 2000). This implies that catchments have long-tailed travel time distributions, and thus retain soluble contaminants for unexpectedly long timespans. Long-term monitoring data from North America, Britain, and Scandinavia show that this fractal behavior characterizes a wide array of catchments. How can this fractal scaling arise in such diverse settings? One can show that advection and dispersion of spatially distributed rainfall tracer inputs will generate fractal tracer time series, as long as the flow system is highly dispersive (Kirchner et al., in press). This implies that subsurface flow in small catchments is dominated by large conductivity contrasts, such as arise from macropores, fracture networks, and similar large-scale heterogeneities in subsurface conductivity. One can also use spectral methods to analyze long-term time series of water fluxes in rainfall and streamflow. Spectral analysis of hydrologic time series measures the downslope propagation of the hydraulic potential waves that mobilize runoff, whereas spectral analysis of tracer time series clocks the propagation of water itself through the catchment. Water fluxes in streamflow exhibit non-fractal scaling, instead of the fractal 1/f scaling shown by chemical tracers. These observations imply that hydrologic signals are transmitted downslope more rapidly, and with much less dispersion, than chemical tracer signals are. Thus small upland catchments transmit hydraulic potentials (which drive runoff) much less dispersively than they transport water itself. These observations provide important constraints for theoretical models of subsurface flow and transport in

  8. Land use/land cover change and implications for ecosystems services in the Likangala River Catchment, Malawi

    NASA Astrophysics Data System (ADS)

    Pullanikkatil, Deepa; Palamuleni, Lobina G.; Ruhiiga, Tabukeli M.

    2016-06-01

    Likangala River catchment in Zomba District of Southern Malawi is important for water resources, agriculture and provides many ecosystem services. Provisioning ecosystem services accrued by the populations within the catchment include water, fish, medicinal plants and timber among others. In spite of its importance, the River catchment is under threat from anthropogenic activities and land use change. This paper studies land uses and land cover change in the catchment and how the changes have impacted on the ecosystem services. Landsat 5 and 8 images (1984, 1994, 2005 and 2013) were used to map land cover change and subsequent inventorying of provisioning ecosystem services. Participatory Geographic Information Systems and Focus group discussions were conducted to identify provisioning ecosystems services that communities benefit from the catchment and indicate these on the map. Post classification comparisons indicate that since 1984, there has been a decline in woodlands from 135.3 km2 in 1984 to 15.5 km2 in 2013 while urban areas increased from 9.8 km2 to 23.8 km2 in 2013. Communities indicated that provisioning ecosystems services such as forest products, wild animals and fruits and medicinal plants have been declining over the years. In addition, evidence of catchment degradation through waste disposal, illegal sand mining, deforestation and farming on marginal lands were observed. Population growth, urbanization and demand for agricultural lands have contributed to this land use and land cover change. The study suggests addressing catchment degradation through integrated method where an ecosystems approach is used. Thus, both the proximate and underlying driving factors of land-use and land cover change need to be addressed in order to sustainably reduce ecosystem degradation.

  9. A differential equation for specific catchment area

    NASA Astrophysics Data System (ADS)

    Gallant, John C.; Hutchinson, Michael F.

    2011-05-01

    Analysis of the behavior of specific catchment area in a stream tube leads to a simple nonlinear differential equation describing the rate of change of specific catchment area along a flow path. The differential equation can be integrated numerically along a flow path to calculate specific catchment area at any point on a digital elevation model without requiring the usual estimates of catchment area and width. The method is more computationally intensive than most grid-based methods for calculating specific catchment area, so its main application is as a reference against which conventional methods can be tested. This is the first method that provides a benchmark for more approximate methods in complex terrain with both convergent and divergent areas, not just on simple surfaces for which analytical solutions are known. Preliminary evaluation of the D8, M8, digital elevation model networks (DEMON), and D∞ methods indicate that the D∞ method is the best of those methods for estimating specific catchment area, but all methods overestimate in divergent terrain.

  10. Topic: Catchment system dynamics: Processes and feedbacks

    NASA Astrophysics Data System (ADS)

    Keesstra, Saskia

    2015-04-01

    In this meeting we can talk about my main expertise: the focus of my research ocus revolves around understanding catchment system dynamics in a holistic way by incorporating both processes on hillslopes as well as in the river channel. Process knowledge enables explanation of the impact of natural and human drivers on the catchment systems and which consequences these drivers have for water and sediment connectivity. Improved understanding of the catchment sediment and water dynamics will empower sustainable land and river management and mitigate soil threats like erosion and off-side water and sediment accumulation with the help of nature's forces. To be able to understand the system dynamics of a catchment, you need to study the catchment system in a holistic way. In many studies only the hillslopes or even plots are studied; or only the channel. However, these systems are connected and should be evaluated together. When studying a catchment system any intervention to the system will create both on- as well as off sites effects, which should especially be taken into account when transferring science into policy regulations or management decisions.

  11. Identifying dominant controls on hydrologic parameter transfer from gauged to ungauged catchments - A comparative hydrology approach

    NASA Astrophysics Data System (ADS)

    Singh, R.; Archfield, S. A.; Wagener, T.

    2014-09-01

    Daily streamflow information is critical for solving various hydrologic problems, though observations of continuous streamflow for model calibration are available at only a small fraction of the world's rivers. One approach to estimate daily streamflow at an ungauged location is to transfer rainfall-runoff model parameters calibrated at a gauged (donor) catchment to an ungauged (receiver) catchment of interest. Central to this approach is the selection of a hydrologically similar donor. No single metric or set of metrics of hydrologic similarity have been demonstrated to consistently select a suitable donor catchment. We design an experiment to diagnose the dominant controls on successful hydrologic model parameter transfer. We calibrate a lumped rainfall-runoff model to 83 stream gauges across the United States. All locations are USGS reference gauges with minimal human influence. Parameter sets from the calibrated models are then transferred to each of the other catchments and the performance of the transferred parameters is assessed. This transfer experiment is carried out both at the scale of the entire US and then for six geographic regions. We use classification and regression tree (CART) analysis to determine the relationship between catchment similarity and performance of transferred parameters. Similarity is defined using physical/climatic catchment characteristics, as well as streamflow response characteristics (signatures such as baseflow index and runoff ratio). Across the entire US, successful parameter transfer is governed by similarity in elevation and climate, and high similarity in streamflow signatures. Controls vary for different geographic regions though. Geology followed by drainage, topography and climate constitute the dominant similarity metrics in forested eastern mountains and plateaus, whereas agricultural land use relates most strongly with successful parameter transfer in the humid plains.

  12. Identifying dominant controls on hydrologic parameter transfer from gauged to ungauged catchments: a comparative hydrology approach

    USGS Publications Warehouse

    Singh, R.; Archfield, S.A.; Wagener, T.

    2014-01-01

    Daily streamflow information is critical for solving various hydrologic problems, though observations of continuous streamflow for model calibration are available at only a small fraction of the world’s rivers. One approach to estimate daily streamflow at an ungauged location is to transfer rainfall–runoff model parameters calibrated at a gauged (donor) catchment to an ungauged (receiver) catchment of interest. Central to this approach is the selection of a hydrologically similar donor. No single metric or set of metrics of hydrologic similarity have been demonstrated to consistently select a suitable donor catchment. We design an experiment to diagnose the dominant controls on successful hydrologic model parameter transfer. We calibrate a lumped rainfall–runoff model to 83 stream gauges across the United States. All locations are USGS reference gauges with minimal human influence. Parameter sets from the calibrated models are then transferred to each of the other catchments and the performance of the transferred parameters is assessed. This transfer experiment is carried out both at the scale of the entire US and then for six geographic regions. We use classification and regression tree (CART) analysis to determine the relationship between catchment similarity and performance of transferred parameters. Similarity is defined using physical/climatic catchment characteristics, as well as streamflow response characteristics (signatures such as baseflow index and runoff ratio). Across the entire US, successful parameter transfer is governed by similarity in elevation and climate, and high similarity in streamflow signatures. Controls vary for different geographic regions though. Geology followed by drainage, topography and climate constitute the dominant similarity metrics in forested eastern mountains and plateaus, whereas agricultural land use relates most strongly with successful parameter transfer in the humid plains.

  13. Erosion studies at Lake Pyhäjärvi catchment (SW Finland)

    NASA Astrophysics Data System (ADS)

    Kirkkala, Teija; Ventelä, Anne-Mari; Tarvainen, Marjo; Jolma, Ari

    2014-05-01

    Lake Säkylän Pyhäjärvi is a large and shallow lake located in the centre of an intensive agricultural area in southwest Finland and it suffering from eutrophication. The nutrient load to Pyhäjärvi comes from diffuse agricultural sources in the catchment. The dominant land cover in the catchment area (22%) is made by cultivated fields, the rest comprising forests, peat lands and built-up areas. The soils of the Pyhäjärvi catchment are erosion sensitive clay, silt, till and peat. The suspended solid and nutrient transport of the main rivers flowing to the lake has been monitored since 1980's. Most part (over 70 %) of phosphorus load is particulate and erosion originated. In recent years the climate change has changed runoff patterns. In winter, mean air temperature is about -2.1 ºC and the catchment is also normally covered by snow in winter. However, in recent years there have been many years with higher winter time temperature and precipitation. In winter the fields are usually without vegetation cover and rainfalls increase erosion. There are already clear long term changes observed in runoff patterns and suspended solid load patterns. The erosion risk invention has been made to Yläneenjoki catchment in order to allocate erosion preventing measures. Sedimentation ponds, wetlands, buffer zones and filters have been used to catch the suspended solids from runoff but these methods are inadequate. In order to efficiently reduce nutrient load to the lake, the focus of the restoration measures should be in the soil, especially erosion preventing. Therefore more deep understanding and studying of erosion processes are needed. Runoff and erosion amounts and patterns should be measured in different types of fields should be done and combined to GIS-analysis.

  14. Agricultural Microbiology.

    ERIC Educational Resources Information Center

    Brill, Winston J.

    1981-01-01

    Elucidates strategies for applying microbiological techniques to traditional agricultural practices. Discusses the manipulation of microorganisms that live with plants and also the problems involved in the introduction of new genes into crop plants by recombinant DNA methods. (CS)

  15. Agricultural Geophysics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The four geophysical methods predominantly used for agricultural purposes are resistivity, electromagnetic induction, ground penetrating radar (GPR), and time domain reflectometry (TDR). Resistivity and electromagnetic induction methods are typically employed to map lateral variations of apparent so...

  16. Model for quantifying the synergies between farmland biodiversity conservation and water protection at catchment scale.

    PubMed

    Helin, Janne; Hyytiäinen, Kari; Korpela, Eeva-Liisa; Kuussaari, Mikko

    2013-12-15

    This paper studies joint provision of two environmental non-market commodities related to agriculture: biodiversity conservation and water protection. We provide an optimising tool for analysing spatial dependencies of multifunctional agriculture at catchment scale. We show that efficiency gains can be achieved by spatial allocation and choice of the type of vegetation. In particular, inclusion of meadow nectar plants in the founding grass seed mixture of set-asides was found out to be an economically efficient measure to promote biodiversity and water protection on warm, steep slopes. PMID:24201218

  17. Agricultural Waste.

    PubMed

    Shu, Huajie; Zhang, Panpan; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2015-10-01

    The management and disposal of agricultural waste are drawn more and more attention because of the increasing yields and negative effects on the environment. However, proper treatments such as converting abundant biomass wastes into biogas through anaerobic digestion technology, can not only avoid the negative impacts, but also convert waste into available resources. This review summarizes the studies of nearly two hundred scholars from the following four aspects: the characterization, reuse, treatment, and management of agricultural waste. PMID:26420088

  18. Impacts of climate and land use changes on the hydrological and erosion processes of two contrasting Mediterranean catchments.

    PubMed

    Serpa, D; Nunes, J P; Santos, J; Sampaio, E; Jacinto, R; Veiga, S; Lima, J C; Moreira, M; Corte-Real, J; Keizer, J J; Abrantes, N

    2015-12-15

    The impacts of climate and land use changes on streamflow and sediment export were evaluated for a humid (São Lourenço) and a dry (Guadalupe) Mediterranean catchment, using the SWAT model. SWAT was able to produce viable streamflow and sediment export simulations for both catchments, which provided a baseline for investigating climate and land use changes under the A1B and B1 emission scenarios for 2071-2100. Compared to the baseline scenario (1971-2000), climate change scenarios showed a decrease in annual rainfall for both catchments (humid: -12%; dry: -8%), together with strong increases in rainfall during winter. Land use changes were derived from a socio-economic storyline in which traditional agriculture is replaced by more profitable land uses (i.e. corn and commercial forestry at the humid site; sunflower at the dry site). Climate change projections showed a decrease in streamflow for both catchments, whereas sediment export decreased only for the São Lourenço catchment. Land use changes resulted in an increase in streamflow, but the erosive response differed between catchments. The combination of climate and land use change scenarios led to a reduction in streamflow for both catchments, suggesting a domain of the climatic response. As for sediments, contrasting results were observed for the humid (A1B: -29%; B1: -22%) and dry catchment (A1B: +222%; B1: +5%), which is mainly due to differences in the present-day and forecasted vegetation types. The results highlight the importance of climate-induced land-use change impacts, which could be similar to or more severe than the direct impacts of climate change alone. PMID:26298249

  19. Catchments network on badlands around Mediterranean area (RESOBAM)

    NASA Astrophysics Data System (ADS)

    Copard, Yoann; Lebouteiller, Caroline; Regues-Munoz, David; Latron, Jerome; Solé-Benet, Albert; Canton, Yolanda; Nadal-Romero, Estela; Della Seta, Marta; Rossi, Mauro; Capolongo, Domenico; Maquaire, Olivier; Forey, Estelle; Di-Giovanni, Christian; Gallart, Francesc; Delmonte, Maurizio; Vergari, Francesca; Massei, Nicolas; Torri, Dino

    2016-04-01

    Between 2013 and 2014, a network funded by MISTRALS-ENVIMED institution, was born around some instrumented catchments developing a badland-type morphology. This network has grouped 3 countries (France, Spain and Italy) with 12 scientific labs. RESOBAM has concerned two sites in France (Draix-Bléone and Vaches Noires), three in Spain (Vallcebre, Araguas and El Cautivo) and some sites in Italy (Tuscany, Basilicata). Main goal of this network was to federate the research around badlands at the European scale, by proposing some scientific topics as: sediment and water transports / budget, (bio)geochemical cycles, agricultural (farming), education, restoration, cultural heritage, soil conservation / biodiversity, climatic change etc. Other main interests were also to propose some common scientific projects and the development of students exchanges. This communication presents the synthesis of our four meetings held at Draix, Zaragoza, Almeriá and Rouen and some perspectives to continue this network.

  20. Catchment scale molecular composition of hydrologically mobilized dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Raeke, Julia; Lechtenfeld, Oliver J.; Oosterwoud, Marieke R.; Bornmann, Katrin; Tittel, Jörg; Reemtsma, Thorsten

    2016-04-01

    Increasing concentrations of dissolved organic matter (DOM) in rivers of temperate catchments in Europe and North Amerika impose new technical challenges for drinking water production. The driving factors for this decadal increase in DOM concentration are not conclusive and changes in annual temperatures, precipitation and atmospheric deposition are intensely discussed. It is known that the majority of DOM is released by few but large hydrologic events, mobilizing DOM from riparian wetlands for export by rivers and streams. The mechanisms of this mobilization and the resulting molecular composition of the released DOM may be used to infer long-term changes in the biogeochemistry of the respective catchment. Event-based samples collected over two years from streams in three temperate catchments in the German mid-range mountains were analyzed after solid-phase extraction of DOM for their molecular composition by ultra-high resolution mass spectrometry (FT-ICR MS). Hydrologic conditions, land use and water chemistry parameters were used to complement the molecular analysis. The molecular composition of the riverine DOM was strongly dependent on the magnitude of the hydrologic events, with unsaturated, oxygen-enriched compounds being preferentially mobilized by large events. This pattern is consistent with an increase in dissolved iron and aluminum concentrations. In contrast, the relative proportions of nitrogen and sulfur bearing compounds increased with an increased agricultural land use but were less affected by the mobilization events. Co-precipitation experiments with colloidal aluminum showed that unsaturated and oxygen-rich compounds are preferentially removed from the dissolved phase. The precipitated compounds thus had similar chemical characteristics as compared to the mobilized DOM from heavy rain events. Radiocarbon analyses also indicated that this precipitated fraction of DOM was of comparably young radiocarbon age. DOM radiocarbon from field samples

  1. Combination of geochemical and hydrobiological tracers for the analysis of runoff generating processes in a lowland catchment

    NASA Astrophysics Data System (ADS)

    Faber, Claas; Wu, Naicheng; Ulrich, Uta; Fohrer, Nicola

    2015-04-01

    Since lowlands are characterised by flat topography and low hydraulic gradients, groundwater inflow has a large influence to streamflow generation in such catchments. In catchments with intense agricultural land use, artificial drainages are often another major contributor to streamflow. They shorten the soil passage and thus change the matter retention potential as well as runoff dynamics of a catchment. Contribution of surface runoff to streamflow is usually less important in volume. However, due to high concentrations of agrochemicals, surface runoff can constitute an important entry pathway into water bodies, especially if strong precipitation events coincide with fertilizer or pesticide application. The DFG funded project "Separating surface runoff from tile drainage flow in agricultural lowland catchments based on diatoms to improve modelled runoff components and phosphorous transport" investigates prevalent processes in this context in a 50 km² lowland catchment (Kielstau, Schleswig-Holstein, Germany) with the goal of improving existing models. End Member Mixing Analysis (EMMA) is used in the project to determine the relative importance of groundwater, tile drainage and surface runoff to streamflow at daily time steps. It became apparent that geochemical tracers are suitable for distinguishing surface runoff, but are weak for the separation of tile drainage and groundwater influence. We attribute this to the strong and complex interaction between soil water and shallow groundwater tables in the catchment. Recent studies (e.g. Pfister et al. 2011, Tauro et al. 2013) show the potential of diatoms as indicators for hydrological processes. Since we found diatoms to be suitable for the separation of tile drainage and stream samples (Wu et al., unpublished data) in our catchment, we are able to include diatom derived indices (e.g. density, species moisture indices, diversity indices) as traces in EMMA. Our results show that the inclusion of diatom data in the

  2. Sensitivity maps for impacts of land management on an extreme flood in the Hodder catchment, UK

    NASA Astrophysics Data System (ADS)

    O'Donnell, G.; Ewen, J.; O'Connell, P. E.

    It is increasingly recognised that the management of land and the management of water are strongly interdependent, and that integrated management approaches are needed. There is evidence that modern land management practices have an effect on runoff generation in rural upland areas, so there is the potential to use land management control as a tool in flood risk mitigation programmes. Flooding from historical extreme rainfall events must be considered when designing mitigation programmes, especially if the designs have to take into account the possibility that such events will become more frequent in the future. The largest 90 min rainfall ever recorded in the UK was 117 mm, recorded in 1967 in the Dunsop tributary (25 km 2) of the Hodder catchment, northwest England. Extensive land management changes have recently been made in the catchment, including peat restoration, tree planting and reductions in sheep stocking density, and the analysis of the flooding in 1967 has been undertaken as part of a wider study on the potential impact of the recent changes. A method is demonstrated in which maps of sensitivity are plotted which show how peak flows for extreme events are affected by spatial patterns of changes in runoff generation. This method uses a gridded model for runoff generation containing an embedded hydraulic model of the river network which can calculate sensitivities efficiently and accurately using reverse algorithmic differentiation. The modelling examines the sensitivity of the hydrograph peak at the catchment outlet to changes in flashy runoff generation, which can be affected by land management practices including the blocking of open drainage channels in peat moorland. It is concluded that, as a result of hydraulic and geomorphologic dispersion in the network, changes in land management that affect the flashiness of runoff generation at small scales would probably have had only a relatively minor effect on the flow peaks at the outlet from the

  3. Programmable Logic Controllers.

    ERIC Educational Resources Information Center

    Insolia, Gerard; Anderson, Kathleen

    This document contains a 40-hour course in programmable logic controllers (PLC), developed for a business-industry technology resource center for firms in eastern Pennsylvania by Northampton Community College. The 10 units of the course cover the following: (1) introduction to programmable logic controllers; (2) DOS primer; (3) prerequisite…

  4. Towards catchment classification by means of environmental tracers and landscape analysis: The Attert catchment in Luxembourg

    NASA Astrophysics Data System (ADS)

    Wrede, S.; Pfister, L.; Krein, A.; Fenicia, F.; Bogaard, T. A.; Uhlenbrook, S.; Savenije, H. H. G.

    2010-05-01

    Until recently hydrological research has been mainly focusing on detailed investigations at small spatial scales, resulting in a set of more and more complex physically-based and spatially distributed hydrologic models. While much of the research effort today is targeted to advance these hydrological model predictions at the catchment scale, shortcomings remain to adequately capture the dominating hydrological processes across a range of scales that translate into the rainfall-runoff response of a catchment. Thus, studies addressing the fundamental relations between catchment structure and function are urgently needed, as they help catchment classification by advancing our knowledge about suitable catchment signatures and controls at different spatial and temporal scales. In our study in the nested Attert catchment in the Grand-Duchy of Luxembourg (Europe) we investigate how environmental tracer dynamics, hydrological response behavior and landscape analysis can help to identify such dominating controls on runoff generation across multiple scales. Techniques to characterize landscape structure and hydrological processes are complementary applied to identify scales in which shifts of the dominant hydrological processes occur. These dominating controls in turn provide a more integrated perspective of catchment structure and functioning that can be used for catchment classification based on functional response.

  5. A new emission-based approach for regulation of N losses from agricultural areas to surface waters

    NASA Astrophysics Data System (ADS)

    Rosenstand Poulsen, Jane; Kronvang, Brian; Bering Ovesen, Niels; Piil, Kristoffer; Kolind Hvid, Søren

    2015-04-01

    Demands for a reduction and hence regulation of nitrogen (N) emissions to streams, lakes and coastal areas are a central part of many river basin management plans under the EU Water Framework Directive. Therefore, large focus has been placed on exploring different mitigation options that can assist in reducing the N emission from agricultural areas. However, the spatial variability in landscape, geology and hydrology entails significant differences in the vulnerability of catchments to intense agricultural activities. Hence, if rigid regulations of N emissions are applied without considering this variability, it will not necessarily lead to an optimum balance between applied fertilisers, yields and loss of excess N to the surrounding surface waters. Therefore, the overall purpose of this pilot study is to develop a concept for regulation of nutrient emissions to surface waters based on a comprehensive stream monitoring design in order to measure the temporal and spatial transport of N at sub-catchment scale. The purpose of such a monitoring design is twofold: i) quantification of the actual N emissions from a given agricultural sub-catchment or even individual farms; ii) quantification at sub-catchment scale of nitrate retention that may ultimately lead to a more precise regulation of N emissions from agricultural areas to surface waters. In order to investigate down to which scale it is feasible to quantify N emissions to surface waters and to develop the best monitoring concept, three catchments subdivided into several sub-catchments in Denmark will be studied during the period 2014-2017. The catchments represent different landscapes and geological settings as well as three different hydrological regimes. In the three catchments, hydrometric stations have been established at the outlet of the drainage networks where continuous measurements are made of water stage. In addition daily water samples and weekly grab samples of water are taken and weekly discharge

  6. Connectivity influences on nutrient and sediment migration in the Wartburg catchment, KwaZulu-Natal Province, South Africa

    NASA Astrophysics Data System (ADS)

    Kollongei, Kipkemboi J.; Lorentz, Simon A.

    Non-point-source (NPS) pollution of surface and groundwater by sediment and nutrient loads emanating from agricultural catchments is a prominent environmental issue, with major consequences on water supply and aquatic ecosystem quality. The concept of connectivity has proved invaluable in understanding migration of NPS pollutants in catchments. Observations of sediments or suspended solids (SS), nitrate (NO3) and phosphorous (P) fluxes alongside stable water isotope sampling were made on a nested basis at field and catchment (41 km2) scales for a series of events in the Wartburg catchment, South Africa. The nested catchment scale sampling was focused on control features in the stream network, including road crossings, farm dams and wetland zones. The analyzed stable water (δ18O and δ2H) isotopes results were used to interpret the connectivity of the contributing land forms and the stream network. The results reveal the dominant influences of farm dams and wetlands in limiting the downstream migration of sediment and nutrients for all but the most intense events. Certain events resulted in mixing in the dams and larger resultant outflow than inflow loads. These occurrences appear to be as a result of combinations of reservoir status, catchment antecedent conditions and rainfall depth and intensity. The nutrients loads between Bridge 1 and Bridge 2 stations reflect the bedrock control, where contributions from sugar cane hillslopes between these stations are not retained, even in the short wetland upstream of Bridge 2. Isotope analyses reveal that the headwaters, comprising 70% of the catchment area, contribute as little as 29% of the total catchment discharge, due to impoundments in this area. However, this contribution varies significantly for different events, reaching a maximum of 78% of the catchment discharge. It can therefore be concluded that nutrients and sediment migration in the Wartburg catchment is greatly influenced by connectivity. The δ18O and δ2H

  7. Modelling of catchment nitrogen concentrations response to observed varying fertilizer application intensities

    NASA Astrophysics Data System (ADS)

    Jomaa, Seifeddine; Jiang, Sanyuan; Yang, Xiaoqiang; Rode, Michael

    2016-04-01

    Eutrophication is a serious environmental problem. Despite numerous experimental and modelling efforts, understanding of the effect of land use and agriculture practices on in-stream nitrogen fluxes is still not fully achieved. This study combined intensive field monitoring and numerical modelling using 30 years of surface water quality data of a drinking water reservoir catchment in central Germany. The Weida catchment (99.5 km2) is part of the Elbe river basin and has a share of 67% of agricultural land use with significant changes in agricultural practices within the investigation period. The geology of the Weida catchment is characterized by clay schists and eruptive rocks, where rocks have low permeability. The semi-distributed hydrological water quality HYPE (Hydrological Predictions for the Environment) model was used to reproduce the measured data. First, the model was calibrated for discharge and nitrate-N concentrations (NO3-N) during the period 1997-2000. Then, the HYPE model was validated successfully for three different periods 1983-1987, 1989-1996 and 2000-2003, which are charaterized by different fertilizer application rates (with lowest discharge prediction performance of NSE = 0.78 and PBIAS = 3.74%, considering calibration and validation periods). Results showed that the measured as well as simulated in-stream nitrate-N concentration respond quickly to fertilizer application changes (increase/decrease). This rapid response can be explained with short residence times of interflow and baseflow runoff components due to the hardrock geological properties of the catchment. Results revealed that the surface runoff and interflow are the most dominant runoff components. HYPE model could reproduce reasonably well the NO3-N daily loads for varying fertilizer application, when detailed input data in terms of crop management (field-specific survey) are considered.

  8. "Upstream Thinking": the catchment management approach of a water provider

    NASA Astrophysics Data System (ADS)

    Grand-Clement, E.; Ross, M.; Smith, D.; Anderson, K.; Luscombe, D.; Le Feuvre, N.; Brazier, R. E.

    2012-04-01

    Human activities have large impacts on water quality and provision. Water companies throughout the UK are faced with the consequences of poor land management and need to find appropriate solutions to decreasing water quality. This is particularly true in the South West of England, where 93% of the drinking water is sourced from rivers and reservoirs: large areas of drained peatlands (i.e. Exmoor and Dartmoor National Parks) are responsible for a significant input of dissolved organic carbon (DOC) discolouring the water, whilst poorly managed farming activities can lead to diffuse pollution. Alongside the direct environmental implications, poor water quality is partly increasing water treatment costs and will drive significant future investment in additional water treatment, with further repercussions on customers. This highlights the need for water companies throughout the UK, and further afield, to be more involved in catchment management. "Upstream Thinking" is South West Water's (SWW) approach to catchment management, where working with stakeholders to improve water quality upstream aims to avoid increasingly costly solutions downstream. This approach has led the company to invest in two major areas of work: (1) The Farmland programme where problematic farm management practices and potential solutions are identified, typically 40% of the required investment is then offered in exchange for a legal undertaking to maintain the new farm assets in good condition for 25 years; (2) The Mires programme which involves heavy investment in peatland restoration through the blocking of open ditches in order to improve water storage and quality in the long term. From these two projects, it has been clear that stakeholder involvement of groups such as local farmers, the Westcountry Rivers Trust, the Exmoor National Park Authority, the Environment Agency, Natural England and the Exmoor Society is essential, first because it draws in catchment improvement expertise which is not

  9. The River EdenDTC Project: A National Demonstration Test Catchment

    NASA Astrophysics Data System (ADS)

    Benskin, C.; Surridge, B.; Deasy, C.; Woods, C.; Rimmer, D.; Lees, E.; Owens, G.; Jonczyk, J.; Quinton, J.; Wilkinson, M.; Perks, M.; Quinn, P.; Barker, P.; Haygarth, P.; Burke, S.; Reaney, S.; Watson, N.

    2012-04-01

    Our environment is a complex system of interactions between natural process and anthropogenic activities that disrupt them. It is crucial to manage the balance for continued food production whilst maintaining the quality of the environment. The challenges we face include managing the impact of agricultural land use on aquatic quality and biodiversity as an integral system, rather than as separate issues. In order to do this, it is critical to understand how the different components are linked - how does land use affect our water courses and ground water, and their associated ecosystems, and how can the impact of agricultural land use on these systems be minimised? Regulating farm nutrient management through measures that minimise sources, their exposure to mobilisation, and reduce drainage pathways to water courses are all fundamental to the UK's approach to meeting the Water Framework Directive objective of achieving 'good ecological status' in all surface and groundwater bodies by 2015. The EdenDTC project is part of a 5-year national Demonstration Test Catchments (DTC) environmental scheme, aiming to understand the above issues through combining scientific research with local knowledge and experience from multiple stakeholders. The DTC project is a 5-year initiative by Defra, Welsh Assembly Government and the Environment Agency, which encompasses a research platform covering three distinct river catchments: the Eden in Cumbria; the Wensum in Norfolk; and the Avon in Hampshire. Within the EdenDTC, the impact and effects of multiple diffuse pollutants on ecosystems and sustainable food production are being studied on a river catchment scale. Three 10 km2 focus catchments, selected to represent the different farming practices and geologies observed across the Eden, have been instrumented to record the dynamics of agricultural diffuse pollution at multiple scales. Within each focus catchment, two sub-catchments were selected: one control and one mitigation, in which

  10. Non-linearities in hydrological connectivity and microbiological flux in nested catchments - implications of environmental change

    NASA Astrophysics Data System (ADS)

    Tetzlaff, D.; Soulsby, C.; Birkel, C.; Capell, R.; Speed, M.

    2009-12-01

    The non-linearities of catchment hydrological behaviour are strongly influenced by the connectivity of hillslopes and channel networks, particularly where overland flow is an important runoff mechanism. Such surface connectivity also controls the flux of microbiological pollutants (coliform bacteria) from areas of live stock grazing which can have serious health implications for potable water supplies. We report a nested catchment study where hydrological and tracer monitoring over a two year period has been coupled with regular sampling for faecal indicator organisms (FIOs). The study has been based in catchments with mixed landuse where FIOs are derived from livestock (sheep and cows) in agricultural land and wild animals (red deer) on moorlands. At all scales (3-1800km2), high levels of FIO were transient and episodic and strongly correlated with periods of high hydrological connectivity. We show how this non-linearity in connectivity can be captured within a dynamic hydrological model. The model was used, along with climate change predictions, to assess possible scenarios of change in connectivity and microbiological contamination in catchments with different land use.

  11. Interactions between upland catchment and lowland rivers: an applied Australian case study

    NASA Astrophysics Data System (ADS)

    Brizga, S. O.; Finlayson, B. L.

    1994-05-01

    Persistent allegations have been made, mainly by Victorian farmers, that channel and floodplain aggradation are occuring on the floodplain of the Snowy River in Victoris as a consequence of a accelaerated erosion of degraded agricultural land in parts of the New South Wales upland catchment. These claims prompted the Victorian Department of Water Resources to initiate geomorphological investigations involving reviews of historical evidence, including the squential aerial photographs, and a study of sediment sources based on environmental tracers. A qualitative approach set within a sediment budget framework was adopted for data integration, a detailed quantitative analysis being precluded by financial, temporal and practical constrainsts. No compelling evidence was found to support claims of recent channel aggradation in the downstream Snowy River. Transfer of sediment eroded from catchment slopes in NSW to the lowland floodplain in Victoria is indirect, with some sediments stored temporarily in fans and floodplains within tributary catchments and in the Snowy valley for long delay times. Storage and interbasin transfer of water as part of the Snowy Mountains Scheme have affected sediment delivery. The catchment upstream of Lake Jindabyne is effectively isolated by this large impoundment, and sediment transport rates as far downstream as the Delegate River junction appear to have significantly decreased as the result of the considerable reduction in discharge.

  12. Heavy metal distribution and controlling factors within coastal plain sediments, Bells Creek catchment, southeast Queensland, Australia.

    PubMed

    Liaghati, Tania; Preda, Micaela; Cox, Malcolm

    2004-01-01

    Bells Creek catchment in southeast Queensland (Australia) is a non-industrialised coastal plain limited to small settlements and agricultural land. A study was initiated to examine elevated metal concentrations and to assess horizontal and vertical distribution of those elements. Ninety-nine samples were analysed for Cr, V, Ni, Cu, Zn, Pb, As, Fe, Mn and Al. Total organic carbon, sulfur content and mineralogy of samples along with land-use practices across the catchment were used to identify processes which influence metal distribution. A comparison between metal concentration within the study area and mean heavy metal content of standard sandstone showed that except for Mn, all other metals showed elevated levels throughout the catchment. When metal concentrations were compared to parent bedrock, however, it was concluded that elevated levels are likely to be natural. A normalisation procedure was applied to the data set and this analysis validated that elevated trace metal concentrations in most samples are not due to artificial contamination. While surficial estuarine sediments were only enriched in V, soils were dominantly enriched in Cr, Zn and V. Overall, geochemistry and mineralogy of the samples show the effect of both natural and anthropogenic inputs to the catchment, however, natural processes are more dominant than anthropogenic inputs in concentrating metals. PMID:14592571

  13. Anthropogenic nitrogen sources and exports in a village-scale catchment in Southeast China.

    PubMed

    Cao, Wenzhi; Hong, Huasheng; Zhang, Yuzhen; Chen, Nengwang; Zeng, Yue; Wang, Weiping

    2006-01-01

    An experimental village-scale catchment was selected for investigation of nitrogen (N) sources and exports. The mean N application rate over the catchment was 350.2 kg N ha(-1), but this rate varied spatially and temporally. The N leaching loss rate varied from 8.1 to 52.7 kg N ha(-1) under different land use regimes. The average N leaching loss rate was 13.4 kg N ha(-1) over the whole catchment, representing about 3.8% of the total N inputs. The N export rate through stormflows was 28.8 kg N ha(-1), about 8.2% of the total N inputs. Seasonal patterns showed that 95% of N exports through stormflows occurred during July to September in 2002. Overall, the maximum riverine N exports were 12.1% of total N inputs and 15.5% of the inorganic fertilizer N applied. Understanding N sources and exports in a village-scale catchment can provide a knowledge base for amelioration of diffuse agricultural pollution. PMID:16528595

  14. Extended principle component analysis - a useful tool to understand processes governing water quality at catchment scales

    NASA Astrophysics Data System (ADS)

    Selle, B.; Schwientek, M.

    2012-04-01

    Water quality of ground and surface waters in catchments is typically driven by many complex and interacting processes. While small scale processes are often studied in great detail, their relevance and interplay at catchment scales remain often poorly understood. For many catchments, extensive monitoring data on water quality have been collected for different purposes. These heterogeneous data sets contain valuable information on catchment scale processes but are rarely analysed using integrated methods. Principle component analysis (PCA) has previously been applied to this kind of data sets. However, a detailed analysis of scores, which are an important result of a PCA, is often missing. Mathematically, PCA expresses measured variables on water quality, e.g. nitrate concentrations, as linear combination of independent, not directly observable key processes. These computed key processes are represented by principle components. Their scores are interpretable as process intensities which vary in space and time. Subsequently, scores can be correlated with other key variables and catchment characteristics, such as water travel times and land use that were not considered in PCA. This detailed analysis of scores represents an extension of the commonly applied PCA which could considerably improve the understanding of processes governing water quality at catchment scales. In this study, we investigated the 170 km2 Ammer catchment in SW Germany which is characterised by an above average proportion of agricultural (71%) and urban (17%) areas. The Ammer River is mainly fed by karstic springs. For PCA, we separately analysed concentrations from (a) surface waters of the Ammer River and its tributaries, (b) spring waters from the main aquifers and (c) deep groundwater from production wells. This analysis was extended by a detailed analysis of scores. We analysed measured concentrations on major ions and selected organic micropollutants. Additionally, redox-sensitive variables

  15. Stakeholder discourse and water management in a catchment in northern Italy

    NASA Astrophysics Data System (ADS)

    Lupo Stanghellini, P. S.; Collentine, D.

    2007-06-01

    The Water Framework Directive (WFD; directive 2000/60/EC) was created to ensure the sustainable use of water resources in the European Union. A central guideline included throughout the directive is a call for the participation of stakeholders in the management of these resources. Involving stakeholders is an important step to ensure that catchment management plans take into consideration local experience in the development of these plans and the impact of the plans on local interests. This paper describes and analyses the results of a series of workshops to facilitate implementation of the WFD at a catchment level based on the stakeholder participation model, CATCH. To test the usefulness of the stakeholder participation model CATCH for water management in a catchment area, a sub-catchment in an alpine valley in the north-east of Italy, the Alta Valsugana in the Province of Trento, was chosen as the setting for a series of workshops. In this valley water is fundamental for activities associated with agriculture, domestic use, energy production, sports and recreation. In the recent past the valley has had serious problems related to water quality and quantity. Implementation of water management plans under the WFD may lead to conflicts within the catchment between different stakeholder interest groups. Including stakeholders in the development of management plans not only follows the guidelines of the WFD but also could result in a more locally adapted and acceptable plan for the catchment. A new stakeholder analysis methodology was developed and implemented in order to identify the relevant stakeholders of the area and then two sets of workshops involving the key stakeholders identified were conducted in Spring 2006. The CATCH meetings were a new experience for the participants, who had to deal with both the principles of the WFD in general and the participation requirement in particular. During the meetings, the CATCH model played a very important role in

  16. From natural to human-dominated floodplains - A Holocene perspective for the Dijle catchment, Belgium

    NASA Astrophysics Data System (ADS)

    Broothaerts, Nils; Verstraeten, Gert; Kasse, Cornelis; Bohncke, Sjoerd; Notebaert, Bastiaan; Vandenberghe, Jef

    2015-04-01

    Floodplain systems underwent important changes in many West and Central European catchments through the late Holocene. To better understand the relation between these landscape changes and human disturbances, geomorphic fieldwork needs to be complemented by quantitative measures of human impact in the landscape. In this study, we provide an holistic discussion in which we combine detailed data on floodplain changes with detailed data on human impact for the Dijle catchment (758 km²), Belgium. Human impact in the catchment was quantified based on statistical analysis of pollen data of six alluvial study sites. The results show that during the Neolithic Period, human impact was nearly absent and floodplains consisted of a strongly vegetated marshy environment where organic material accumulated, which is considered as the natural state of the floodplain. From the Bronze Age onwards, human impact increased and caused an increase in soil erosion and hillslope-floodplain connectivity. Consequently, sediment input in the floodplain system increased and floodplain geoecology changed towards an open floodplain dominated by clastic overbank deposits, mainly as the indirect result of an intensification of agricultural activities. Based on these data, a generalized model of floodplain development is presented: At the scale of the entire Dijle catchment, the gradual changes in floodplain morphology coincided with the gradually increasing human impact in the catchment, which suggests a linearity between the external forcing (human impact) and geomorphic response (floodplain change). However, at the narrow floodplains in the headwaters, the gradual increase in human impact contrasts with the abrupt change in floodplain geoecology, only triggered when human impact reached a threshold. Observed differences at catchment scale in time-lags and in the process-response model are attributed to differences in hillslope-floodplain connectivity, the location within the catchment and to

  17. Establishment of a hydrological monitoring network in a tropical African catchment: An integrated participatory approach

    NASA Astrophysics Data System (ADS)

    Gomani, M. C.; Dietrich, O.; Lischeid, G.; Mahoo, H.; Mahay, F.; Mbilinyi, B.; Sarmett, J.

    Sound decision making for water resources management has to be based on good knowledge of the dominant hydrological processes of a catchment. This information can only be obtained through establishing suitable hydrological monitoring networks. Research catchments are typically established without involving the key stakeholders, which results in instruments being installed at inappropriate places as well as at high risk of theft and vandalism. This paper presents an integrated participatory approach for establishing a hydrological monitoring network. We propose a framework with six steps beginning with (i) inception of idea; (ii) stakeholder identification; (iii) defining the scope of the network; (iv) installation; (v) monitoring; and (vi) feedback mechanism integrated within the participatory framework. The approach is illustrated using an example of the Ngerengere catchment in Tanzania. In applying the approach, the concept of establishing the Ngerengere catchment monitoring network was initiated in 2008 within the Resilient Agro-landscapes to Climate Change in Tanzania (ReACCT) research program. The main stakeholders included: local communities; Sokoine University of Agriculture; Wami Ruvu Basin Water Office and the ReACCT Research team. The scope of the network was based on expert experience in similar projects and lessons learnt from literature review of similar projects from elsewhere integrated with local expert knowledge. The installations involved reconnaissance surveys, detailed surveys, and expert consultations to identify best sites. First, a Digital Elevation Model, land use, and soil maps were used to identify potential monitoring sites. Local and expert knowledge was collected on flow regimes, indicators of shallow groundwater plant species, precipitation pattern, vegetation, and soil types. This information was integrated and used to select sites for installation of an automatic weather station, automatic rain gauges, river flow gauging stations

  18. What makes catchment management groups "tick"?

    PubMed

    Oliver, P

    2001-01-01

    The work of catchment management groups throughout Australia represents a significant economic and social investment in natural resource management. Institutional structures and policies, the role of on-ground coordinators, facilitation processes, citizen participation and social capital are critical factors influencing the success of catchment management groups. From a participant-researcher viewpoint, this paper signposts research directions and themes that are being pursued from the participant/coordinator, catchment group, and lead government/non-government agency perspective on the influence of these factors on the success of a catchment management group in the Pumicestone Region of Southeast Queensland, Australia. Research directions, themes and discussion/reflection points for practitioners include--the importance of understanding milieu; motivation; success; having fun; "networking networks"; involvement of "nontraditional" stakeholders; development of stakeholder/participant partnerships; learning from other practitioners; methods of stakeholder/participant representation; evaluation; the need for guiding principles or philosophy; the equivalence of planning, implementation, evaluation, and resourcing; catchments as fundamental units of Nature; continuity of support for groups; recognising a new role for government; working with existing networks; and the need for an eclectic approach to natural resource management. PMID:11424936

  19. Hydropedological insights when considering catchment classification

    NASA Astrophysics Data System (ADS)

    Bouma, J.; Droogers, P.; Sonneveld, M. P. W.; Ritsema, C. J.; Hunink, J. E.; Immerzeel, W. W.; Kauffman, S.

    2011-02-01

    Soil classification systems are analysed in relation to the functioning and characterisation of catchments. Soil classifications are useful to create systematic order in the overwhelming quantity of different soils in the world and to extrapolate data available for a given soil type to soils elsewhere with identical classifications. However, such classifications are based on permanent characteristics as formed by the soil forming factors over often very long periods of time and this does not necessarily match with characteristics and parameters needed for functional soil characterization focusing, for example, on catchment hydrology. Hydropedology has made contributions towards functional characterization of soils as is illustrated for recent hydrological catchment studies. However, much still needs to be learned about the physical behaviour of anisotropic, heterogeneous field soils with varying soil structures during the year and the suggestion is made to first focus on improving simulation of catchment hydrology, incorporating hydropedological expertise, before embarking on a classification effort which involves major input of time and involves the risk of distraction. In doing so, we advise to also define other characteristics for catchment performance than the traditionally measured discharge rates.

  20. Influence of urbanization pattern on stream flow of a peri-urban catchment under Mediterranean climate

    NASA Astrophysics Data System (ADS)

    Ferreira, Carla S. S.; Walsh, Rory P. D.; Ferreira, António J. D.; Steenhuis, Tammo S.; Coelho, Celeste A. O.

    2015-04-01

    The demand for better life quality and lower living costs created a great pressure on peri-urban areas, leading to significant land-use changes. The complexity of mixed land-use patterns, however, presents a challenge to understand the hydrological pathways and streamflow response involved in such changes. This study assesses the impact of a actively changing Portuguese peri-urban area on catchment hydrology. It focuses on quantifying streamflow delivery from contributing areas, of different land-use arrangement and the seasonal influence of the Mediterranean climate on stream discharge. The study focuses on Ribeira dos Covões a small (6 km2) peri-urban catchment on the outskirts of Coimbra, one of the main cities in central Portugal. Between 1958 and 2012 the urban area of the catchment expanded from 8% to 40%, mostly at the expense of agriculture (down from 48% to 4%), with woodland now accounting for the remaining 56% of the catchment area. The urban area comprises contrasting urban settings, associated with older discontinuous arrangement of buildings and urban structures and low population density (<25 inhabitants/km), and recent well-defined urban cores dominated by apartment blocks and high population density (9900 inhabitants/km). The hydrological response of the catchment has been monitored since 2007 by a flume installed at the outlet. In 2009, five rainfall gauges and eight additional water level recorders were installed upstream, to assess the hydrological response of different sub-catchments, characterized by distinct urban patterns and either limestone or sandstone lithologies. Annual runoff coefficients range between 14% and 22%. Changes in annual baseflow index (36-39% of annual rainfall) have been small with urbanization (from 34% to 40%) during the monitoring period itself. Annual runoff coefficients were lowest (14-7%) on catchments >80% woodland and highest (29% on sandstone; 18% on limestone) in the most urbanized (49-53% urban) sub-catchments

  1. Space research programme

    NASA Astrophysics Data System (ADS)

    Magnusson, Per; Englund, Jan; Norberg, Olle

    2001-08-01

    A major highlight of the Swedish national programme was the launch of the Odin Orbital Observatory in February 2001. The atmospheric profiles measured by Odin will be calibrated with rocket and balloon validation flights during the second half of 2001. A continuation of the satellite programme after Odin depends on the outcome of an ongoing assessment and an additional budget. The future ESA microgravity programme will be of high importance for European and Swedish science and applications using weightless conditions, and for the utilisation of the International Space Station (ISS). It should also make sure that the European independent capability for launching efficient sounding rockets is preserved and developed.

  2. Agricultural chemical export dynamics in a watershed

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-06-01

    chemicals filter through a catchment is important for managing water quality. Using a concept of the catchment as a physicochemical filter, Guan et al. examined nitrate, phosphate, and atrazine loads in the Little Vermillion River watershed, a tile-drained watershed in Illinois. They analyzed a 10-year data set using mathematical signal processing to investigate spatial and temporal patterns in chemical concentrations and discharge rate. They found that export of these chemicals had a linear relationship with streamflow at annual scales—the higher the streamflow, the more these chemicals were exported from the watershed. The researchers' approach helps identify the roles of different hydrological flow paths in controlling chemical export at different spatial and temporal scales and reveals that chemical inputs overwhelm normal biogeochemical processing in these agricultural systems, leading to high long-term average rates of export. (Water Resources Research, doi:10.1029/ 2010WR009997, 2011)

  3. Designing Schemes to Mitigate Non-Point Source Water Pollution from Agriculture: The Value of High-Resolution Hydrochemical and Hydrophysical Data

    NASA Astrophysics Data System (ADS)

    Barber, N.; Reaney, S. M.

    2014-12-01

    To effectively mitigate non-point source water pollution from agriculture, first it is vital to have an awareness of a watershed's hydrological and contaminant regime. Understanding the magnitude and timing of pollutant export, as well as the pathways by which different constituents are delivered to a water course, is paramount. One approach to gaining this type of knowledge is to observe pollutant fluxes at the watershed outlet. The River Eden Demonstration Test Catchments programme uses in-situ monitoring equipment to provide high-resolution (30 minute) data for three mixed-agriculture watersheds (ca. 10km2) in north western England. Determinands measured include turbidity, phosphorus, nitrate, chlorophyll-a, dissolved oxygen, conductivity, pH and temperature, along with river discharge and rainfall. Provided with these data, and an awareness of significant agricultural activities carried out in the watershed on an annual basis, this study demonstrates how it is possible to identify different pollutant transfer pathways, along with their spatio-temporal nature, and their relative importance. This information is then used to inform appropriate mitigation design. In relation to this purpose, the pros and cons of the different hydrochemical and hydrophysical data are described, and recommendations made for other determinands that should be considered for measurement in future similar studies.

  4. Before and After Integrated Catchment Management in a Headwater Catchment: Changes in Water Quality

    NASA Astrophysics Data System (ADS)

    Hughes, Andrew O.; Quinn, John M.

    2014-12-01

    Few studies have comprehensively measured the effect on water quality of catchment rehabilitation measures in comparison with baseline conditions. Here we have analyzed water clarity and nutrient concentrations and loads for a 13-year period in a headwater catchment within the western Waikato region, New Zealand. For the first 6 years, the entire catchment was used for hill-country cattle and sheep grazing. An integrated catchment management plan was implemented whereby cattle were excluded from riparian areas, the most degraded land was planted in Pinus radiata, channel banks were planted with poplar trees and the beef cattle enterprise was modified. The removal of cattle from riparian areas without additional riparian planting had a positive and rapid effect on stream water clarity. In contrast, the water clarity decreased in those sub-catchments where livestock was excluded but riparian areas were planted with trees and shrubs. We attribute the decrease in water clarity to a reduction in groundcover vegetation that armors stream banks against preparatory erosion processes. Increases in concentrations of forms of P and N were recorded. These increases were attributed to: (i) the reduction of instream nutrient uptake by macrophytes and periphyton due to increased riparian shading; (ii) uncontrolled growth of a nitrogen fixing weed (gorse) in some parts of the catchment, and (iii) the reduction in the nutrient attenuation capacity of seepage wetlands due to the decrease in their areal coverage in response to afforestation. Our findings highlight the complex nature of the water quality response to catchment rehabilitation measures.

  5. Catchment scale multi-objective flood management

    NASA Astrophysics Data System (ADS)

    Rose, Steve; Worrall, Peter; Rosolova, Zdenka; Hammond, Gene

    2010-05-01

    Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the Environment Agency, are managing an innovative project on the Holnicote Estate in south west England to demonstrate the benefits of using good rural land management practices to reduce flood risk at the both the catchment and sub-catchment scales. The Holnicote Estate is owned by the National Trust and comprises about 5,000 hectares of land, from the uplands of Exmoor to the sea, incorporating most of the catchments of the river Horner and Aller Water. There are nearly 100 houses across three villages that are at risk from flooding which could potentially benefit from changes in land management practices in the surrounding catchment providing a more sustainable flood attenuation function. In addition to the contribution being made to flood risk management there are a range of other ecosystems services that will be enhanced through these targeted land management changes. Alterations in land management will create new opportunities for wildlife and habitats and help to improve the local surface water quality. Such improvements will not only create additional wildlife resources locally but also serve the landscape response to climate change effects by creating and enhancing wildlife networks within the region. Land management changes will also restore and sustain landscape heritage resources and provide opportunities for amenity, recreation and tourism. The project delivery team is working with the National Trust from source to sea across the entire Holnicote Estate, to identify and subsequently implement suitable land management techniques to manage local flood risk within the catchments. These

  6. Flood-related contamination in catchments affected by historical metal mining: an unexpected and emerging hazard of climate change.

    PubMed

    Foulds, S A; Brewer, P A; Macklin, M G; Haresign, W; Betson, R E; Rassner, S M E

    2014-04-01

    Floods in catchments affected by historical metal mining result in the remobilisation of large quantities of contaminated sediment from floodplain soils and old mine workings. This poses a significant threat to agricultural production and is preventing many European river catchments achieving a 'good chemical and ecological status', as demanded by the Water Framework Directive. Analysis of overbank sediment following widespread flooding in west Wales in June 2012 showed that flood sediments were contaminated above guideline pollution thresholds, in some samples by a factor of 82. Most significantly, silage produced from flood affected fields was found to contain up to 1900 mg kg(-1) of sediment associated Pb, which caused cattle poisoning and mortality. As a consequence of climate related increases in flooding this problem is likely to continue and intensify. Management of contaminated catchments requires a geomorphological approach to understand the spatial and temporal cycling of metals through the fluvial system. PMID:24463253

  7. Natural and human influence on loess gully catchment evolution: A case study from Lublin Upland, E Poland

    NASA Astrophysics Data System (ADS)

    Superson, Józef; Rodzik, Jan; Reder, Jan

    2014-05-01

    This paper presents the functioning of a gully system catchment in the loess area of the Lublin Upland (eastern Poland) based on investigations of soil and sediment sequences filling the valley floors and correlative sediments on the alluvial fan at the valley outlet. Stages of the catchment's evolution are proposed, from the Meso-Holocene (8400-5100 BP) followed by prehistorical and historical stages of human activity to modern times (gully erosion). Varying erosional processes have been identified over a period of about 2800 years BP: washing and sediment deposition on the alluvial fan at early stages followed by multi branched gully system development. Later on, land use change of deforestation and agriculture led to dissection of gully edges by a system of badlands. This study demonstrates the roll of the human factor as a shifting agent between dominant geomorphic processes in the same catchment area over a long period of time.

  8. Large-scale pesticide monitoring across Great Barrier Reef catchments--Paddock to Reef Integrated Monitoring, Modelling and Reporting Program.

    PubMed

    Smith, Rachael; Middlebrook, Rachael; Turner, Ryan; Huggins, Rae; Vardy, Suzanne; Warne, Michael

    2012-01-01

    The transport and potential toxicity of pesticides in Queensland (QLD) catchments from agricultural areas is a key concern for the Great Barrier Reef (GBR). In 2009, a pesticide monitoring program was established as part of the Australian and QLD Governments' Reef Plan (2009). Samples were collected at eight End of System sites (above the tidal zone) and three sub-catchment sites. At least two pesticides were detected at every site including insecticides, fungicides, herbicides, and the Reef Plan's (2009) five priority photosystem II (PSII) herbicides (diuron, atrazine, hexazinone, tebuthiuron and ametryn). Diuron, atrazine and metolachlor exceeded Australian and New Zealand water quality guideline trigger values (TVs) at eight sites. Accounting for PSII herbicide mixtures increased the estimated toxicity and led to larger exceedances of the TVs at more sites. This study demonstrates the widespread contamination of pesticides, particularly PSII herbicides, across the GBR catchment area which discharges to the GBR. PMID:21920563

  9. Agricultural Biodiversity.

    ERIC Educational Resources Information Center

    Postance, Jim

    1998-01-01

    The extinction of farm animals and crops is rarely brought up during discussions of endangered species and biodiversity; however, the loss of diversity in crops and livestock threatens the sustainability of agriculture. Presents three activities: (1) "The Colors of Diversity"; (2) "Biodiversity among Animals"; and (3) "Heirloom Plants." Discusses…

  10. AGRICULTURAL EXTENSION.

    ERIC Educational Resources Information Center

    FARQUHAR, R.N.

    AUSTRALIAN AGRICULTURAL EXTENSION HAS LONG EMPHASIZED TECHNICAL ADVISORY SERVICE AT THE EXPENSE OF THE SOCIOECONOMIC ASPECTS OF FARM PRODUCTION AND FARM LIFE. ONLY IN TASMANIA HAS FARM MANAGEMENT BEEN STRESSED. DEMANDS FOR THE WHOLE-FARM APPROACH HAVE PRODUCED A TREND TOWARD GENERALISM FOR DISTRICT OFFICERS IN MOST STATES. THE FEDERAL GOVERNMENT,…

  11. AGRICULTURAL EDUCATION.

    ERIC Educational Resources Information Center

    DEALTON, ERNEST L.

    TODAY'S SUCCESSFUL FARMER MUST POSSESS THE SKILLS OF A BUSINESSMAN, SCIENTIST, AND MECHANIC TO SURVIVE COMPETITION IN AGRICULTURE, THE LARGEST INDUSTRY IN THE UNITED STATES. THIS COMPETITION HAS CAUSED AN INCREASE IN THE SIZE OF FARMS AND RANCHES IN AN ATTEMPT TO CURTAIL OPERATIONAL EXPENSES AND TO INCREASE PRODUCTION. WITH THE SCIENTIFIC…

  12. Validation of Pacific Northwest hydrologic landscapes at the catchment scale

    EPA Science Inventory

    The interaction between the physical properties of a catchment (form) and climatic forcing of precipitation and energy control how water is partitioned, stored, and conveyed through a catchment (function). Hydrologic Landscapes (HLs) were previously developed across Oregon and de...

  13. SOTANCP3 Scientific Programme

    NASA Astrophysics Data System (ADS)

    2014-12-01

    The programme for the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics" which was held at the KGU (Kanto Gakuin University) Kannai Media Center (8th floor of Yokohoma Media Business Center (YMBC))

  14. WORLD WATER ASSESSMENT PROGRAMME

    EPA Science Inventory

    The overall objective of the World Water Assessment Programme is to support the building of global security - food, environment, economic, social and political security -- through an integrated comprehensive freshwater assessment.The specific objectives within the assessment pr...

  15. Effects of land use on greenhouse gas fluxes and soil properties of wetland catchments in the Prairie Pothole Region of North America

    USGS Publications Warehouse

    Tangen, Brian A.; Finocchiaro, Raymond G.; Gleason, Robert A.

    2015-01-01

    Results suggest that soil organic carbon is lost when relatively undisturbed catchments are converted for agriculture, and that when non-drained cropland catchments are restored, CH4 fluxes generally are not different than the pre-restoration baseline. Conversely, when drained cropland catchments are restored, CH4 fluxes are noticeably higher. Consequently, it is important to consider the type of wetland restoration (drained, non-drained) when assessing restoration benefits. Results also suggest that elevated N2O fluxes from cropland catchments likely would be reduced through restoration. The overall variability demonstrated by this study was consistent with findings of other wetland investigations and underscores the difficulty in quantifying the GHG balance of wetland systems.

  16. Characterizing streamflow generation in Alpine catchments

    NASA Astrophysics Data System (ADS)

    Chiogna, Gabriele; Cano Paoli, Karina; Bellin, Alberto

    2016-04-01

    Developing effective hydrological models for streamflow generation in Alpine catchments is challenging due to the inherent complexity of the intertwined processes controlling water transfer from hillslopes to streams and along the river network. With water discharge as the sole observational variable it is impossible to differentiate between different streamflow sources, and modelling activity is often limited to simplified phenomenological rainfall-runoff models. This study focuses on quantifying streamflow sources at different temporal scales and the associated uncertainty by using natural tracer data (electrical conductivity, oxygen and hydrogen stable isotopes ratios) as observational variables supplementing streamflow measurements. We determine the spatial and temporal hydrological behavior and the mean residence time of water in the Vermigliana catchment, North-Eastern Italy and we separate contributions to streamflow originating from Presena and Presanella glaciers, both exerting a strong control on the hydrologic budget of the study site. Furthermore, we identify a seasonal control on the effect of storm events. The catchment responded rapidly to precipitation events in early autumn, it was unaffected by precipitation events in early spring, while runoff generation was enhanced by snow melting in late autumn. Air temperature is identified as the main controlling parameter, in addition to precipitation. Two-component mixing analysis showed that the relative contribution of new water, which can contribute up to 75% of total streamflow, is very rapid. Only two hours time-lag was observed between the beginning of the precipitation event and the emergence of a significant contribution of new water. These results evidence the relevance of mixing between pre-event and event water in the Vermigliana catchment, and in similar high elevation Alpine catchments. This study provides new insights on the dynamics of streamflow generation in Alpine catchments and a

  17. Programmable Logic Application Notes

    NASA Technical Reports Server (NTRS)

    Katz, Richard

    1998-01-01

    This column will be provided each quarter as a source for reliability, radiation results, NASA capabilities, and other information on programmable logic devices and related applications. This quarter's column will include some announcements and some recent radiation test results and evaluations of interest. Specifically, the following topics will be covered: the Military and Aerospace Applications of Programmable Devices and Technologies Conference to be held at GSFC in September, 1998, proton test results, heavy ion test results, and some total dose results.

  18. Programmable Logic Application Notes

    NASA Technical Reports Server (NTRS)

    Katz, Richard

    1998-01-01

    This column will be provided each quarter as a source for reliability, radiation results, NASA capabilities, and other information on programmable logic devices and related applications. This quarter's column will include some announcements and some recent radiation test results and evaluations of interest. Specifically, the following topics will be covered: the Military and Aerospace Applications of Programmable Devices and Technologies Conference to be held at GSFC in September, 1998, proton test results, and some total dose results.

  19. Identification of internal flow dynamics in two experimental catchments

    USGS Publications Warehouse

    Hansen, D.P.; Jakeman, A.J.; Kendall, C.; Weizu, G.

    1997-01-01

    Identification of the internal flow dynamics in catchments is difficult because of the lack of information in precipitation -stream discharge time series alone. Two experimental catchments, Hydrohill and Nandadish, near Nanjing in China, have been set up to monitor internal flows reaching the catchment stream at various depths, from the surface runoff to the bedrock. With analysis of the precipitation against these internal discharges, it is possible to quantify the time constants and volumes associated with various flowpaths in both catchments.

  20. Picturing and modelling catchments by representative hillslopes

    NASA Astrophysics Data System (ADS)

    Loritz, Ralf; Hassler, Sibylle; Jackisch, Conrad; Zehe, Erwin

    2016-04-01

    Hydrological modelling studies often start with a qualitative sketch of the hydrological processes of a catchment. These so-called perceptual models are often pictured as hillslopes and are generalizations displaying only the dominant and relevant processes of a catchment or hillslope. The problem with these models is that they are prone to become too much predetermined by the designer's background and experience. Moreover it is difficult to know if that picture is correct and contains enough complexity to represent the system under study. Nevertheless, because of their qualitative form, perceptual models are easy to understand and can be an excellent tool for multidisciplinary exchange between researchers with different backgrounds, helping to identify the dominant structures and processes in a catchment. In our study we explore whether a perceptual model built upon an intensive field campaign may serve as a blueprint for setting up representative hillslopes in a hydrological model to reproduce the functioning of two distinctly different catchments. We use a physically-based 2D hillslope model which has proven capable to be driven by measured soil-hydrological parameters. A key asset of our approach is that the model structure itself remains a picture of the perceptual model, which is benchmarked against a) geo-physical images of the subsurface and b) observed dynamics of discharge, distributed state variables and fluxes (soil moisture, matric potential and sap flow). Within this approach we are able to set up two behavioral model structures which allow the simulation of the most important hydrological fluxes and state variables in good accordance with available observations within the 19.4 km2 large Colpach catchment and the 4.5 km2 large Wollefsbach catchment in Luxembourg without the necessity of calibration. This corroborates, contrary to the widespread opinion, that a) lower mesoscale catchments may be modelled by representative hillslopes and b) physically

  1. Controls on suspended sediment, particulate and dissolved organic carbon export from two adjacent catchments with contrasting land-uses, Exmoor UK.

    NASA Astrophysics Data System (ADS)

    Glendell, M.; Brazier, R. E.

    2012-04-01

    The fluvial export of total organic carbon (particulate and dissolved) plays an important role in the transportation of organic carbon from terrestrial to aquatic ecosystems, with implications for the understanding of the global carbon cycle and calculations of regional carbon budgets. The terrestrial biosphere contains large amounts of stored carbon in the soil and vegetation, thus a small change in the terrestrial carbon pool may have significant implications for atmospheric CO2 concentrations. Since the onset of agriculture, human activities have accelerated soil erosion rates 10- to 100- fold above all estimated natural background levels, especially in the uplands and at lower latitudes, whilst increasing DOC concentrations over the past decades have been reported in rivers across Western Europe and North America, raising concerns about potential destabilisation of the terrestrial soil carbon pool. The increased input of fine sediment and organic carbon into aquatic environments is also an important factor in stream water quality, being responsible for direct ecological effects as well as transport of a range of contaminants. Many factors, such as topography, hydrological regime and vegetation are known to influence the fluvial export of carbon from catchments. However, most work to date has focused on DOC losses from either forested or peaty catchments, with only limited studies examining the controls and rates of TOC (dissolved and particulate) fluxes from agricultural catchments, particularly during flood events. This research aims to: • Quantify the fluxes of total suspended sediment, total dissolved and total particulate carbon in two adjacent catchments with contrasting land-uses and • Examine the controlling factors of total fluvial carbon fluxes in a semi-natural and agricultural catchment in order to assess the impact of agricultural land-use on fluvial carbon export. The two contrasting study catchments (the Aller and Horner), in south

  2. The hydrological response of a small catchment after the abandonment of terrace cultivation. A study case in northwestern Spain

    NASA Astrophysics Data System (ADS)

    Llorente-Adán, Jose A.; Lana-Renault, Noemí; Galilea, Ianire; Ruiz-Flaño, Purificacion

    2015-04-01

    Terrace construction for cultivation results in a complete transformation of the hillslopes to a series of flat sectors and almost vertical steps. This strategy, which involves a redistribution of soils and a re-organization of the drainage network, provides fertile soil over steep slopes, improves infiltration and controls overland flow under conditions of intense rainstorms. In Camero Viejo (north-western Iberian ranges) most of the hillslopes are occupied by terraced fields. During the XXth century, rural population declined and agricultural practices were abandoned. In this area, a small catchment (1.9 km2) was monitored in 2012 for studying how the abandonment of agricultural terraces affect water and sediment transfer from the hillslopes to the channels. Terraces occupy 40% of the catchment and are covered by sparse grass and shrubs. The equipment installed in the catchment registers continuously meteorological data, discharge and water table fluctuations. Data on suspended sediment transport is obtained by means of a rising-stage sampler. Here we present the hydrological results corresponding to the years 2012-13 and 2013-14. The hydrological response of the catchment was moderate (annual runoff coefficient < 0.20), which could be in part explained by the high evapotranspiration rates reported in the area. Lows flows were recorded in summer and autumn, when the water reserves of the catchment were dry, and high flows occurred from January, when the catchment became wetter. The shape of the hydrographs, with slow response times, moderate peakflows and long recession limbs suggested a large contribution of subsurface flow, probably favored by deep and well structured soils in the bench terraces. Soil saturation areas were not observed during the study period, suggesting that soil infiltration processes and subsurface flow are important, and that the drainage system of the terraces is probably well maintained. No suspended sediment has been collected so far

  3. Modeling daily streamflow at ungauged catchments: What information is necessary?

    NASA Astrophysics Data System (ADS)

    Patil, S.; Stieglitz, M.

    2011-12-01

    Streamflow modeling at ungauged catchments involves transfer of information (viz., model structure and parameters) from gauged to ungauged catchments that are judged to be hydrologically similar. In this study, we focus on identifying: (1) what constitutes the critical information that needs to be transferred among hydrologically similar catchments to achieve good predictability using models at ungauged sites, and (2) which is the best approach for transferring this information from gauged to ungauged catchments. We develop a simple hydrologic model with minimal calibration requirement and implement it over 756 catchments located across the continental United States. The model computes water balance at a daily time-step and conceptualizes subsurface runoff through a storage-dependent exponential decline in saturated hydraulic conductivity. Snow accumulation and melt are modeled using the thermal degree-day concept. The calibrated model performs better in humid runoff-dominated regions than in the drier evapotranspiration-dominated regions. Results show that within a region, transfer of hydrograph recession information alone is sufficient for reliable streamflow predictions at ungauged catchments. Information transfer from spatially proximate gauged catchments provides better streamflow predictability at ungauged catchments than transfer from catchments identified as physically similar. When considering spatially proximate catchments, information transfer from multiple donor catchments is preferable to transfer from a single donor catchment.

  4. Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA

    USGS Publications Warehouse

    Shanley, J.B.; Kendall, C.; Smith, T.E.; Wolock, D.M.; McDonnell, Jeffery J.

    2002-01-01

    Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1 topographically controlled increase in surface-saturated area with increasing catchment size; 2 direct runoff over frozen ground; 3 low infiltration in agriculturally compacted soils; 4 differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales. Copyright ?? 2002 John Wiley and Sons, Ltd.

  5. Modeling Runoff from Partially Glacierized Catchments in the Tropical Andes with Different Glacier Coverage and Land Cover Conditions

    NASA Astrophysics Data System (ADS)

    Kinouchi, T.; Mendoza, J.; Luna, J.; Asaoka, Y.

    2014-12-01

    In Bolivian Andes, retreats of tropical glaciers are rapid, thus water resources currently available from glacierized catchments for drinking, agriculture, industry and hydropower would be changed in its volume and variations due to changing climate. Water resources in La Paz and El Alto, the capital city areas of Bolivia, strongly depend on the runoff from partially glacierized catchments located in the Cordillera Real, which is a combined contribution of surface and subsurface flow from glacierized and non-glacierized areas due to rainfall, snow melt and glacier melt. To predict the long-term availability of water resources for the capital city areas, we developed a semi-distributed conceptual glacio-hydrological model that considers various runoff pathways from partially glacierized high-altitudinal catchments located in the outer tropics. In the model, the retarding effect of lakes and wetlands was considered, based on the observed hydraulic functions and distribution of wetlands. The model was applied to three sub-catchments of the Tuni Lake watershed (98km2), from which the water resources for La Paz and El Alto are supplied. With calibrated parameters, the model reproduced well the observed seasonal variations of daily runoff during recent two years. Simulated results of water balance suggested that for the catchment with a larger glacier cover, more than 40% of the annual total runoff is contributed from glacierized areas due to glacier melt and snowmelt. The contribution from glacierized areas in other two sub-catchments, with relatively smaller areas covered by glacier ice, was calculated to be between 10-15%. We found that the role of wetlands and lakes are essential in retarding and regulating the runoff from partially glacierized high-mountain catchments.

  6. Modelling long-term diffuse nitrate pollution at the catchment-scale: Data, parameter and epistemic uncertainty

    NASA Astrophysics Data System (ADS)

    Howden, N. J. K.; Burt, T. P.; Mathias, S. A.; Worrall, F.; Whelan, M. J.

    2011-06-01

    SummaryA model of catchment-scale nitrate transport is presented for a small, rural headwater basin (Alton Pancras: <10 km 2) in Dorset, UK, for the period 1930-2007. Estimates of annual nitrogen (N) loading were based on parish land-use data, held in the UK's National Archives, and previously reported figures of typical UK N loadings from livestock, fertiliser, ploughing of permanent pasture, atmospheric deposition, biological fixation and crop uptake. Loading calculations were performed within an uncertainty framework to allow for the reliance on literature data sources. Loading calculations show that all significant sources must be included not just fertiliser application which, at most, contributes 50% of N input in any given year. A simple algorithm was used to transform estimated catchment N loading (1930-2007) into a river nitrate response (observed data: 1980-2004). This assumed N-loads were delayed by some catchment mean travel time (MTT), t a, attenuated according to a Peclet number, P e, converted into solute concentrations by a factor, α, to increase some initial baseline river concentration, C b. Simple graphical translation of estimated catchment N loading to the river concentration data suggested a MTT of around 37 years. As P e → ∞, the transport model simplified to a linear relationship between catchment N load and river nitrate concentration response lagged by the MTT. Hence, the model results suggest that, in this catchment, advection is the dominant mechanism for transport of diffuse pollution from land to river: there is little or no dispersion present. The MTT ( t a) was then reconsidered using an estimated distribution of unsaturated zone depths in the Alton Pancras catchment. Conclusions suggest that, in modelling of long-term nutrient transport, a detailed source term is of much greater importance than a complex hydrogeological model. Implications of epistemic uncertainty, long-term prediction and management of diffuse agricultural

  7. Importance of including small-scale drain discharge data in the calibration of a catchment scale nitrate model

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Refsgaard, J.; Christensen, B. S.; Jensen, K. H.

    2011-12-01

    Nitrate leaching from agricultural areas and the resulting pollution of groundwater and surface waters is one of the largest challenges in water resources management in Denmark. Nitrate can however be naturally degraded under anaerobic conditions and several studies have shown that degradation in the saturated zone removes more than 50% of the nitrate leaching in Danish catchments. For degradation of nitrate to occur in the saturated zone, nitrate must be transported under the redox interface and a correct simulation of the small-scale flow patterns within a catchment is therefore important in nitrate models. The general findings in Danish nitrate modeling studies are that the models perform well at catchment scale, but the predictability of the models decreases at smaller scale. Thus the model predictions are highly uncertain at small scale and the models cannot at present predict areas within a catchment, where the majority of the nitrate is brought under the interface and thus degraded, and areas, where nitrate is transported directly to streams and lakes without any significant reduction. The objective of this study is to test if the small scale performance of a catchment scale nitrate model can be improved by including small scale observation data in the calibration procedure. The study area is the clayey catchment to Lillebæk stream (4.7 km2), located on the island of Funen in Denmark. Due to the presence of clayey top soils subsurface drains are installed and in consequence the stream discharge is highly dominated by drain flow. An integrated transient hydrological model based on the MIKE SHE code has been developed for the study area. The model has been calibrated against hydraulic head measurements and stream discharge measurements from two stations, one covering most of the catchment and the other station approximately half, using the parameter estimator code PEST. Acceptable model performance has been achieved at catchment scale calibrating the model

  8. Anomaly in the rainfall-runoff behaviour of the Meuse catchment. Climate, land-use, or land-use management?

    NASA Astrophysics Data System (ADS)

    Fenicia, F.; Savenije, H. H. G.; Avdeeva, Y.

    2009-09-01

    The objective of this paper is to investigate the time variability of catchment characteristics in the Meuse basin through its effect on catchment response. The approach uses a conceptual model to represent rainfall-runoff behaviour of this catchment, and evaluates possible time-dependence of model parameters. The main hypothesis is that conceptual model parameters, although not measurable quantities, are representative of specific catchment attributes (e.g. geology, land-use, land management, topography). Hence, we assume that eventual trends in model parameters are representative of catchment attributes that may have changed over time. The available hydrological record involves ninety years of data, starting in 1911. During this period the Meuse catchment has undergone significant modifications. The catchment structural modifications, although documented, are not available as "hard-data". Hence, our results should be considered as "plausible hypotheses". The main motivation of this work is the "anomaly" found in the rainfall runoff behaviour of the Meuse basin, where ninety years of rainfall-runoff simulations show a consistent overestimation of the runoff in the period between 1930 and 1965. Different authors have debated possible causes for the "anomaly", including climatic variability, land-use change and data errors. None of the authors considered the way in which the land is used by for instance agricultural and forestry practises. This aspect influenced the model design, which has been configured to account for different evaporation demand of growing forest. As a result of our analysis, we conclude that the lag time of the catchment has decreased significantly over time, which we attribute to more intensive drainage and river training works. Furthermore, we hypothesise that forest rotation has had a significant impact on the evaporation of the catchment. These results contrast with previous studies, where the effect of land-use change on the hydrological

  9. Mapping of geomorphic processes on abandoned fields and cultivated land in small catchments in semi-arid Spain

    NASA Astrophysics Data System (ADS)

    Geißler, C.; Ries, J. B.; Marzolff, I.

    2009-04-01

    In semi-arid landscapes vegetation succession on abandoned agricultural land is a long lasting process due to the water deficit for the best time of the year. During this phase of succession, geomorphic processes like the formation and development of rills, gullies and other geomorphic processes lead to a more or less constant deterioration of the abandoned land. But also on currently cultivated land and under quasi-natural vegetation the processes of soil degradation by flowing water take place. Regarding small catchments like gully catchments, the topography and the land cover (abandoned land, cultivated land, quasi-natural vegetation) are highly important factors in gully formation and soil degradation. Another important point is the distribution of different land cover units and therefore the connectivity of the catchment as described by Bracken & Croke (2007). In this study, 11 catchments of single gullies have been mapped geomorphologically and compared to the rate of gully development derived from small-format aerial photography. It could be shown that there is a high variability of processes due to differences in topography and the way the land is or has been cultivated. On abandoned land, geomorphic processes are highly active and enhance or even predestinate the direction of headcut movement. Another result is that geomorphological mapping of these gully catchments revealed interactions and dependencies of linear erosion features like the connection to the main drainage line, e.g. the gully. In the larger of the observed catchments (>5 ha) it became clear that some catchments have morphological features that tend to enhance connectivity (long rills, shallow drainage lines) and some catchments have features which tend to restrict connectivity (terraces, dense vegetation). In "more connected" catchments the retreat rate of the headcut is generally higher. By the method of geomorphological mapping, valuable information about the soil degrading processes

  10. Role of river bank erosion in sediment budgets of catchments within the Loire river basin (France)

    NASA Astrophysics Data System (ADS)

    Gay, Aurore; Cerdan, Olivier; Poisvert, Cecile; Landemaine, Valentin

    2014-05-01

    Quantifying volumes of sediments produced on hillslopes or in channels and transported or stored within river systems is necessary to establish sediment budgets. If research efforts on hillslope erosion processes have led to a relatively good understanding and quantification of local sources, in-channel processes remain poorly understood and quasi inexistent in global budgets. However, profound landuse changes and agricultural practices have altered river functioning, caused river bank instability and stream incision. During the past decades in France, river channelization has been perfomed extensively to allow for new agricultural practices to take place. Starting from a recent study on the quantification of sediment fluxes for catchments within the Loire river basin (Gay et al. 2013), our aim is to complete sediment budgets by taking into account various sources and sinks both on hillslope and within channel. The emphasis of this study is on river bank erosion and how bank erosion contributes to global budgets. A model of bank retreat is developed for the entire Loire river basin. In general, our results show that bank retreat is on average quite low with approximately 1 cm.yr-1. However, a strong variability exists within the study area with channels displaying values of bank retreat up to ~10 cm.yr-1. Our results corroborate those found by Landemaine et al. in 2013 on a small agricultural catchment. From this first step, quantification of volumes of sediment eroded from banks and available for transport should be calculated and integrated in sediment budgets to allow for a better understanding of basin functioning. Gay A., Cerdan O., Delmas M., Desmet M., Variability of sediment yields in the Loire river basin (France): the role of small scale catchments (under review). Landemaine V., Gay A., Cerdan O., Salvador-Blanes S., Rodriguez S. Recent morphological evolution of a headwater stream in agricultural context after channelization in the Ligoire river (France

  11. Global investigation of vegetation impact on mean annual catchment evapotranspiration

    NASA Astrophysics Data System (ADS)

    Peel, Murray C.; McMahon, Thomas A.; Finlayson, Brian L.

    2010-05-01

    Historically, relationships between catchment vegetation type, evapotranspiration and runoff have been assessed primarily through paired catchment studies. The literature contains results from over 200 of these studies from around the world but two factors limit the applicability of the results to the wider domain. Firstly, catchment areas are generally small (<10 km2). Secondly, the range of climate types is narrow, with temperate (Köppen C) and cold (Köppen D) climate types in the majority. Here we present results from a global assessment of the impact of vegetation type on mean annual catchment evapotranspiration for a large, spatially and climatically diverse dataset of 699 catchments. This assessment is based on analysis of areal precipitation, temperature, runoff, and land cover information from each catchment, which differs from the paired catchment methodology where streamflow responses to a controlled land cover change are assessed. When catchments are grouped by vegetation type, any evidence of differing vegetation impact on actual evapotranspiration will be observed through differences in mean annual actual evapotranspiration, defined as precipitation minus runoff. Stratifying catchments by climate type was observed to be important when assessing the vegetation impact on evapotranspiration. Tropical and temperate forested catchments had significantly higher median evapotranspiration (~170mm and ~130mm, respectively) than non-forested catchments. Cold forested catchments unexpectedly had significantly lower median evapotranspiration (~90mm) than non-forested catchments. No significant difference in median evapotranspiration was found between temperate evergreen and deciduous forested catchments, though sample sizes were small. Temperate evergreen needleleaf forested catchments had significantly higher median evapotranspiration than evergreen broadleaf forested catchments, though again sample sizes were small. The significant difference in median

  12. Identification of weathered structures and aquifers from resistivity observations in the Strengbach catchment (Vosges, France).

    NASA Astrophysics Data System (ADS)

    Gance, Julien; Sailhac, Pascal; Malet, Jean-Philippe; Viville, Daniel; Pierret, Marie-Claire

    2015-04-01

    In low mountain regions, natural water resources used for agriculture or drinking water generally come from natural sources. Management of these water resources is complex for some catchments where most of the water flows is exfiltrating from bedrock aquifers characterized by important spatial heterogeneity and different connectivity levels in space and time. The Strengbach catchment (Vosges, North East France) is a hydro-geochemical observatory monitored for more than 25 years. The numerous geochemical studies have highlighted the existence of different lithological and structural units in the catchment constituted by different weathered granitic aquifers. Their spatial extension has been determined through the measurement of the soil electrical resistivity using 20 Electrical Resistivity Tomography (ERT) profiles. The profiles have been inverted separately with the BERT software in 2D and compared to 2.5 D inversions, where the inversion accounts for the profile crossings. The comparison between 2D and 2.5D inversion results allows validating the 2-D assumption. The 20 profiles are distributed over the complete catchment and cover more densely the water source area of the Strengbach stream. The shallow resistivities (5-10 m) measured highlight several weathered zones possibly characterized by different porosity. A combined analysis with soil water conductivity measurements in boreholes allows proposing a map of the spatial extension of these units. The resistivity data are also used to assess the depth of the main reservoir at the scale of the catchment. The hypothesis of the existence of a deeper reservoir is brought out by Audio-Magneto Telluric (AMT) and Very Low Frequency (VLF) measurements.

  13. Patterns and Pathways of Evolving Catchment Response in NE Italy on a Millennium Scale

    NASA Astrophysics Data System (ADS)

    van Beek, L. P. H. Rens; Feiken, H. Rik

    2015-04-01

    The meso-scale landscape dynamics model, CALEROS, has been developed to simulate the interactions between climate, soil production and erosion, vegetation and land use on geomorphological to human time scales. Starting from an initial landscape consisting of a DTM, soil distribution and underlying lithology, the landscape is free to develop in response to the imposed climate variability and seismicity. In addition to changes in soil distribution and bedrock lowering, this includes the establishment of vegetation as conditioned by a selection of plant functional types and, optionally, population and land use dynamics as conditioned by land use scenarios specifying technological and dietary constraints for different periods. As such CALEROS is well-suited to investigate the relative impacts of climate, land cover and human activities on the hydrological catchment response and the associated sediment fluxes due to soil erosion and mass movements. Here we use CALEROS to investigate the redistribution of water and sediment across a medium-sized catchment in NE Italy. Starting from the same initial conditions, the catchment is subjected respectively to conditions corresponding to the present-day sub-alpine and montane climates of NE Italy, with and without the introduction of agriculture around 5000 BC. For these two catchments, we establish patterns of co-evolution in soil properties and vegetation under pristine and anthropogenically impacted conditions on a millennium-scale. Using summary statistics to describe the emergent properties, we then delineate areas of uniform morphology and describe the various pathways of development. This information allows us to identify elements of consistent hydrological response and the associated transfer of material across different scales. It also provides essential information on feedbacks and the resulting convergence or divergence in landscape development under the impact of climatic events or human intervention. Although the

  14. Geostatistical and Fractal Characteristics of Soil Moisture Patterns from Plot to Catchment Scale Datasets

    NASA Astrophysics Data System (ADS)

    Korres, Wolfgang; Reichenau, Tim G.; Fiener, Peter; Koyama, Christian N.; Bogena, Heye R.; Cornelissen, Thomas; Baatz, Roland; Herbst, Michael; Diekkrüger, Bernd; Vereecken, Harry; Schneider, Karl

    2016-04-01

    Soil moisture and its spatio-temporal pattern is a key variable in hydrology, meteorology and agriculture. The aim of the current study is to analyze spatio-temporal soil moisture patterns of 9 datasets from the Rur catchment (Western Germany) with a total area of 2364 km², consisting of a low mountain range (forest and grassland) and a loess plain dominated by arable land. Data was acquired across a variety of land use types, on different spatial scales (plot to mesoscale catchment) and with different methods (field measurements, remote sensing, and modelling). All datasets were analyzed using the same methodology. In a geostatistical analysis sill and range of the theoretical variogram were inferred. Based on this analysis, three groups of datasets with similar characteristics in the autocorrelation structure were identified: (i) modelled and measured datasets from a forest sub-catchment (influenced by soil properties and topography), (ii) remotely sensed datasets from the cropped part of the total catchment (influenced by the land-use structure of the cropped area), and (iii) modelled datasets from the cropped part of the Rur catchment (influenced by large scale variability of soil properties). A fractal analysis revealed that soil moisture patterns of all datasets show a multi-fractal behavior (varying fractal dimensions, patterns are only self-similar over certain ranges of scales), with at least one scale break and generally high fractal dimensions (high spatial variability). Corresponding scale breaks were found in various datasets and the factors explaining these scale breaks are consistent with the findings of the geostatistical analysis. The joined analysis of the different datasets showed that small differences in soil moisture dynamics, especially at maximum porosity and wilting point in the soils, can have a large influence on the soil moisture patterns and their autocorrelation structure.

  15. Water and sediment dynamics in a small Mediterranean cultivated catchment under cracking soils

    NASA Astrophysics Data System (ADS)

    Inoubli, Nesrine; Raclot, Damien; Moussa, Roger; Habaieb, Hamadi; Le Bissonnais, Yves

    2016-04-01

    Shrink-swell soils, such as those in a Mediterranean climate regime, can cause changes in terms of hydrological and erosive responses due to the changing soil water storage conditions. Only a limited number of long-term studies have focused on the impacts on both hydrological and erosive responses and their interactions in an agricultural environment. In this context, this study aims to document the dynamics of cracks, runoff and soil erosion within a small Mediterranean cultivated catchment and to quantify the influence of crack processes on the water and sediment supplied to a reservoir located at the catchment outlet. Detailed monitoring of the presence of topsoil cracks was conducted within the Kamech catchment (ORE OMERE, Tunisia), and runoff and suspended sediment loads were continuously measured over a long period of time (2005-2012) at the outlets of a field (1.32 ha) and a catchment (263 ha). Analysis of the data showed that topsoil cracks were open approximately half of the year and that the rainfall regime and water table level conditions locally control the seasonal cracking dynamics. Topsoil cracks appeared to seriously affect the generation of runoff and sediment concentrations and, consequently, sediment yields, with similar dynamics observed at the field and catchment outlets. A similar time lag in the seasonality between water and sediment delivery was observed at these two scales: although the runoff rates were globally low during the presence of topsoil cracks, most sediment transport occurred during this period associated with very high sediment concentrations. This study underlines the importance of a good prediction of runoff during the presence of cracks for reservoir siltation considerations. In this context, the prediction of cracking effects on runoff and soil erosion is a key factor for the development of effective soil and water management strategies and downstream reservoir preservation.

  16. Characterization and cartography of topsoil hydraulic properties in a French mountainous peri-urban catchment

    NASA Astrophysics Data System (ADS)

    Gonzalez-Sosa, E.; Braud, I.; Gonzalez-Sosa, E.; Dehotin, J.; Branger, F.; Lagouy, M.

    2009-04-01

    Due to the increase of urbanization and modification of agricultural practices, peri-urban areas experiment a quick change in land use. The impact of such change on the catchment hydrological cycle must be quantified. To achieve this goal, distributed hydrological models offer the ability to take into account land use change, and more specifically its effect on surface infiltration capacity. A distributed assessment of infiltration properties and their variability at the catchment scale is thus of great importance if accurate simulation of the water balance are expected on such catchments. This paper presents a field campaign conducted in a 7 km2 peri-urban catchment, located in the "Mont du Lyonnais" area, close to the city of Lyon (France) in order to document the topsoil hydraulic properties. The sampling strategy was set up in order to sample the largest number of soil/land use combinations. The locations were chosen from a GIS analysis based on the overlapping of the pedology and land use maps, and accessibility consideration. At each location, two types of infiltration tests were performed: infiltration tests under suction using mini-disk infiltrometers and single ring infiltration tests under positive head. Three replicates were performed for each method. Particle size data and organic matter analysis were also conducted at each location. Results will be discussed in terms of soil hydraulic properties and particle size data statistics. Relationship with external factors such as pedological unit, land use, slope, texture will be explored. Preliminary results show that forest and pasture soils exhibit the highest hydraulic conductivity and sorptivity. In order to provide models with values at the modelling unit scale (field and/or sub-catchment scale), existing pedotransfer function will be assessed and if necessary calibrated using the local measurements. Finally a methodology for the cartography of the soil hydraulic properties will be proposed.

  17. Spatiotemporal dynamics of suspended sediment within an actively urbanizing peri-urban catchment in Portugal

    NASA Astrophysics Data System (ADS)

    Walsh, Rory; Ferreira, Carla; Ferreira, Antonio

    2016-04-01

    Suspended sediment levels tend to be enhanced in urban catchments, but vary considerably with (amongst many other factors) the degree of active urban development or redevelopment within the catchment and 'urbanization style'. Relatively little, however, is known about the relationship between suspended solids and urbanization style in peri-urban Mediterranean environments. This paper focuses on spatiotemporal suspended sediment dynamics within a typical Portuguese peri-urban catchment, Ribeira dos Covoes, that is undergoing rapid urbanization. The catchment currently has a 40% urban cover, with 17% impervious surfaces, dispersed between woodland (56%) and agricultural areas (4%). The study uses suspended sediment concentration measurements made at the catchment outlet (ESAC) and in three upstream tributaries: (i) Espírito Santo, with a largest urban area (49%); (ii) Porto Bordalo, 39% urbanized; and (iii) Quinta, 22% urbanized, most of which (18%) being an enterprise park under construction. Water sampling was carried out manually during 10 storm hydrographs between October 2011 and March 2013. Suspended sediment concentrations (SSC) were derived by laboratory analysis of the filtered samples using the gravimetric method. In addition total dissolved solids concentrations (TDS) were estimated using conductivity readings. Greatest SSCs were recorded in the Quinta sub-catchment and at the catchment outlet at ESAC (113-4320 mg L-1 and 200-1656 mg L-1, respectively) than in the Espírito Santo and Porto Bordalo sub-catchments (183-852 mg L-1 and 47-598 mg L-1 respectively, despite their greater impervious cover. The greatest SSCs for Quinta result from it containing the construction site, but it showed lower TDS (56-4010 mg L-1), perhaps due to the coarse sandy nature of the construction site. Higher TDS concentrations, however, were displayed in Porto Bordalo (27-5400 mg L-1), possibly due to the loamy soil. Espírito Santo, comprising sandy-loam soils, displayed 27

  18. Hydrology and sediment yield calibration for the Barasona reservoir catchment (Spain) using SWAT

    NASA Astrophysics Data System (ADS)

    Palazón, Leticia; Navas, Ana

    2013-04-01

    Hydrological and soil erosion models, as Soil and Water Assessment Tool (SWAT), have become very useful tools and increasingly serve as vital components of integrated environmental assessments that provide information outside of direct field experiments and causal observation. The purpose of this study was to improve the calibration of SWAT model to use it in an alpine catchment as a simulator of processes related to water quality and soil erosion. SWAT is spatially semi-distributed, agro-hydrological model that operates on a daily time step (as a minimum) at basin scale. It is designed to predict the impact of management on water, sediment and agricultural chemical yields in ungaged catchments. SWAT provides physically based algorithms as an option to define many of the important components of the hydrologic cycle. The input requirements of the model are used to describe the climate, soil properties, topography, vegetation, and land management practices. SWAT analyzes small or large catchments by discretising into sub-basins, which are then further subdivided into hydrological response units (HRUs) with homogeneous land use, soil type and slope. SWAT model (SWAT2009) coupled with a GIS interface (ArcSWAT), was applied to the Barasona reservoir catchment located in the central Spanish Pyrenees. The 1509 km2 agro-forestry catchment presents a mountain type climate, an altitudinal range close to 3000 meters and a precipitation variation close to 1000 mm/km. The mountainous characteristics of the catchment, in addition to the scarcity of climate data in the region, require specific calibration for some processes. Snowfall and snowmelt are significant processes in the hydrologic regime of the area and were calibrated in a previous work. In this work some of the challenges of the catchment to model with SWAT which affected the hydrology and the sediment yield simulation were performed as improvement of the previous calibration. Two reservoirs, a karst system which

  19. Towards a better understanding of the nature and contribution of the interflow pathway to catchment dynamics

    NASA Astrophysics Data System (ADS)

    Deakin, J.; Misstear, B.; Archbold, M.; Flynn, R.

    2012-04-01

    A detailed understanding of flow and contaminant transfer along each of the key hydrological pathways within a catchment is critical for designing and implementing cost effective Programmes of Measures under the Water Framework Directive. The Contaminant Movement along Pathways Project ('The Pathways Project') is an Irish, EPA STRIVE funded, large multi-disciplinary project which is focussed on understanding and modelling flow and attenuation along each of these pathways for the purposes of developing a catchment management tool. The tool will be used by EPA and RBD catchment managers to assess and manage the impacts of diffuse contamination on stream aquatic ecology. Four main contaminants of interest — nitrogen, phosphorus, sediment and pathogens — are being investigated in four instrumented test catchments. In addition to the usual hydrological and water chemistry/quality parameters typically captured in catchment studies, field measurements at the test catchments include ecological sampling, sediment dynamics, soil moisture dynamics, and groundwater levels and chemistry/quality, both during and between significant rainfall events. Spatial and temporal sampling of waters directly from the pathways of interest is also being carried out. Sixty-five percent of Ireland is underlain by poorly productive aquifers. In these hydrogeological settings, the main pathways delivering flow to streams are overland flow, interflow and shallow bedrock flow. Little is known about the interflow pathway and its relative importance in delivery of flow and contaminants to the streams. Interflow can occur in both the topsoil and subsoil, and may include unsaturated matrix flow, bypass or macropore flow, saturated flow in locally perched water tables and artificial field drainage. Results to date from the test catchment experiments show that artificial field drains play an important role in the delivery of interflow to these streams, during and between rainfall events when

  20. Future Proofing Water Policy and Catchment Management for a Changing Climate: A Case Study of Competing Demands and Water Scarcity in the River Thames and Catchment

    NASA Astrophysics Data System (ADS)

    Whitehead, P. G.; Crossman, J.; Jin, L.

    2011-12-01

    The River Thames Catchment is the major water supply system in Southern England and supplies all of London's water supply from either the River Lee (a tributary of the Thames) or the main river abstraction site at Teddington (see Figure 1) or from groundwater sources in London. There has been a measurable change in rainfall patterns over the past 250 years with reducing summer rainfall and, hence flows, over the past 40 years. In 1976, following 3 dry winters, the London Reservoirs were more or less empty and the river flow direction was reversed to ensure a supply of water for London. Recent climate change studies in the Thames catchments suggest an increasing threat to water supply and also damage to river water quality and ecology. In addition to a changing climate, population levels in London have risen in recent years and the catchment is increasingly vulnerable to land use change. Since the 1920s changes in land use have increased the levels of nitrogen and phosphorus in the catchment and this trend is predicted to be exacerbated as climate change reduces freshwater dilution. Also land use is predicted to change as agriculture becomes more intensive as farmers react to higher grain and food prices. At the same time rising water temperatures has exposed the river to the potential for toxic algal blooms, such as cyanobacteria. This doom and gloom story is being managed however using a range of policy instruments, led by central government and public and private organisations such as Thames Water and the Environment Agency. Measures such as new reservoirs, a water transfer scheme from Wales and water metering to reduce demand are all being actively pursued, as are land management measures to control diffuse pollution. In order to assess the effects of climate change on the Thames catchment a major modelling study has been undertaken. The Integrated Catchment Model (INCA) has been set up for the Thames to model flow, nitrogen, phosphorus and ecology. Climate

  1. Co-evolution of volcanic catchments in Japan

    NASA Astrophysics Data System (ADS)

    Yoshida, T.; Troch, P. A.

    2015-09-01

    Present day landscapes have evolved over time through interactions between the prevailing climates and geological settings. Understanding the linkage between spatial patterns of landforms, soils, and vegetation in landscapes and their hydrological response is critical to make quantitative predictions in ungaged basins. Catchment co-evolution is a theoretical framework that seeks to formulate hypotheses about the mechanisms and conditions that determine the historical development of catchments and how such evolution affects their hydrological response. In this study, we selected 14 volcanic catchments of different ages (from 0.225 to 82.2 Ma) in Japan. We derived indices of landscape properties (drainage density) as well as hydrological response (annual water balance, baseflow index, and flow duration curves) and examined their relation with catchment age and climate (through the aridity index). We found significant correlation between drainage density and baseflow index with age, but not with climate. The age of the catchments was also significantly related to intra-annual flow variability. Younger catchments tend to have lower peak flows and higher low flows, while older catchments exhibit more flashy runoff. The decrease of baseflow with catchment age confirms previous studies that hypothesized that in volcanic landscapes the major flow pathways have changed over time, from deep groundwater flow to shallow subsurface flow. The drainage density of our catchments decreased with age, contrary to previous findings in similar volcanic catchments but of significant younger age than the ones explored here. In these younger catchments, an increase in drainage density with age was observed, and it was hypothesized that this was because of more landscape incision due to increasing near-surface lateral flow paths in more mature catchments. Our results suggests two hypotheses on the evolution of drainage density in matured catchments. One is that as catchments further evolve

  2. CRA-W's committee of intervention: analyse of catchments polluted with pesticides.

    PubMed

    Noel, S; Bah, B B; Collinet, G; Buffet, D; Sorel, A; Hallet, V

    2008-01-01

    In the Walloon Region of Belgium, a committee of intervention has been created to investigate problems of pesticide contamination of various catchments use for drinking water production. This committee involves the Agricultural Research centre--Wallonia (CRA-W, project coordinator) and some University experts. It is funded by the Société Publique de Gestion des Eaux (SPGE). The diagnosis method, base on the AQUAPLAINE method (Arvatis-France), consists of 4 steps. The first step is the preparation of diagnosis (at the office) that takes into account the paper risk of active ingredients. and their uses, the identification of the agricultural parcels, the collection of cartographic and numeric data, the description of the hydrogeological and pedological contexts and the study of the meteorological data in relation with the period of pollution. The second step consists of making a plot diagnosis (on the field) to identify the way of transfer inside the plot and collecting data. At the third step, the people who can apply PPP treatment close to the catchment are met (farmers and city services). Information are collected on treatments applied and on the state of parcels. Based on the hypothesis of pollution cause, the committee proposes solution to solve the problem. One of the catchment that has been investigated by the committee is located at Biesmerée, (Namur province, in Belgium). A temporally contamination was caused by 4 pesticides : chlortoluron, isoproturon, trifluralin and diflufenican. After investigations, it seems that the pollution was probably due to the hydrogeological context. As the river is locally perched over the aquifer, the presence of Poly-aromatic hydrocarbons (PAHs) could be due to the infiltration of surface water inside the catchment or/and to the presence of a sinkhole temporally activated during river flood period. Infiltration rate has to be assessed and river bank impermeabilization is recommended. PMID:19226832

  3. Runoff Variability in Field-scale Catchments and the Implications for Rainffall-Runoff Modeling

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Shuster, W.

    2004-12-01

    In this study long-term rainfall runoff records for two agricultural catchments (ca. 0.5 ha) in the USDA - Agricultural Research Service North Appalachian Experimental Watershed (Coshocton, OH) network were used to address the inter-event and inter-catchment variability of field-scale runoff processes. Through analyses of flood frequency and flow duration, the adjacent fallowed watersheds (WS106 and WS121) were found to be similar in terms of annual flood peaks, but less so in terms of the distribution of their discharge rates. Further investigation was focused on event-scale variations of runoff response and whether these variations can be effectively captured by rainfall-runoff models, which included: a) TR-20 (a lumped model); b) EPA-SWMM (a semi-distributed model); and c) GSSHA (a grid-based, fully distributed model). Each model was used to simulate 41 selected runoff episodes recorded in each of the two catchments, and subsequently calibrated to yield parameter values that maximize the correlation between the simulated and observed runoff peaks. Our results indicate that, despite calibration, the hydrographs derived from all models deviated considerably from actual observations, and on the basis of inter-event fluctuations, which furthermore lacked a conspicuous dependence on the magnitude of runoff peaks. Our findings suggest that, in the absence of information on rainfall distribution and soil moisture, distributed models may not be superior to lumped ones in forecasting runoff responses of field scale catchments; and the correspondence between runoff mechanisms and model representations needs to be better understood and accounted for in order to limit the uncertainties of model predictions.

  4. Investigating the impact of data uncertainty on the estimation of catchment nutrient fluxes.

    NASA Astrophysics Data System (ADS)

    Lloyd, Charlotte; Freer, Jim; Collins, Adrian; Johnes, Penny; Coxon, Gemma

    2014-05-01

    Changing climate and a growing population are increasing pressures on the world's water bodies. Maintaining food security has resulted in changes in agricultural practices, leading to adverse impacts on water quality. To address this problem robust evidence is needed to determine which on-farm mitigation strategies are likely to be most effective in reducing pollutant impacts. The introduction of in-situ quasi-continuous monitoring of water quality provides the means to improve the characterisation of pollutant behaviour and gain new and more robust understanding of hydrological and biogeochemical flux behaviours in catchments. Here we analyse a suite of high temporal resolution data sets generated from in-situ sensor networks within an uncertainty framework to provide robust estimates of nutrient fluxes from catchments impacted by intensive agricultural production practices. Previous research into nutrient flux estimation has focused on assessing the uncertainty associated with the use of different load models to interpolate or extrapolate nutrient data where daily or sub-daily discharge data are generally available and used with lower resolution nutrient concentrations. In such studies examples of datasets where paired discharge and nutrient concentrations are available are used as a benchmark of 'truth' against which the other data models or sample resolutions are tested. This work illustrates that even given high temporal-resolution paired datasets, where no load model is necessary, there will still be significant uncertainties and therefore demonstrates the importance of analysing such data within an uncertainty framework to obtain robust estimates of catchment nutrient loads. This study uses 15-minute resolution paired velocity and stage height data, in order to calculate river discharge, along with high temporal resolution (15 or 30 minute) nutrient data from four field sites collected as part of the Hampshire Avon Demonstration Test Catchment project

  5. Future runoff from glacierized catchments in the Central Andes could substantially decrease

    NASA Astrophysics Data System (ADS)

    Kronenberg, Marlene; Schauwecker, Simone; Huggel, Christian; Salzmann, Nadine; Drenkhan, Fabian; Frey, Holger; Giráldez, Claudia; Gurgiser, Wolfgang; Kaser, Georg; Suarez, Wilson; García Hernández, Javier; Fluixá-Sanmartín, Javier; Ayros, Edwin; Rohrer, Mario

    2016-04-01

    In Peru, about 50% of the energy is produced from hydropower plants. An important amount of this energy is produced with water from glaciated catchments. In these catchments river streamflow is furthermore needed for other socio-economic activities such as agriculture. However, the amount and seasonality of water from glacial melt is expected to undergo strong changes. As glaciers are projected to further decline with continued warming, runoff will become more and more sensitive to possible changes in precipitation patterns. Moreover, as stated by a recent study (Neukom et al., 2015), wet season precipitation sums in the Central Andes could decrease up to 19-33 % by the end of the 21st century compared to present-day conditions. Here, we investigate future runoff availability for selected glacierized catchments in the Peruvian Andes. In a first step, we apply a simplified energy balance and runoff model (ITGG-2.0-R) for current conditions. Thereafter, we model future runoff for different climate scenarios, including the possibility of strongly reduced precipitation. Preliminary findings indicate (i) changes in the seasonal distribution of runoff and (ii) significant reductions of the annual runoff in future for the mentioned scenario with significant precipitation decreases. During early phases of glacier recession, melt leads to increased runoff - respectively compensates for the precipitation reduction in the corresponding scenario - depending on the fraction of catchment glaciation. Glaciers are acting as natural water reservoirs and may buffer the decreasing precipitation in glacierized catchments for a limited period. However, strongly reduced precipitation will have noticeable consequences on runoff, particularly when glacier melt contribution gets smaller and finally is completely missing. This will have consequences on the water availability for hydropower production, agriculture, mining and other water uses. Critical conditions may emerge in particular

  6. A catchment-scale palaeolimnological investigation into multiple forcings of algal community change

    NASA Astrophysics Data System (ADS)

    Moorhouse, H. L.; McGowan, S.; Jones, M.; Brayshaw, S.; Barker, P.; Leavitt, P.

    2013-12-01

    A catchment-scale palaeolimnological investigation of sedimentary algal pigments spanning the past ~200 years was undertaken on lakes which drain into Windermere, England's largest and longest lake. We aimed to determine the relative influence of past regional (climatic, atmospheric deposition) and local (land-use, hydrological modification, point-source pollution) drivers of algal community change by comparing three fertile lowland lakes (Blelham Tarn, Esthwaite Water and Rydal Water) and two upland tarns (Stickle and Easedale Tarns) to better inform a catchment-wide management strategy for Windermere. Drivers of change at the upland sites included atmospheric acid deposition, climatic change and structural modifications caused by dam installation, whereas the influence of agriculture and point-source pollution is greater in the lakes in the lowland parts of the catchment. As a result, contrasting algal responses were noted in the lakes. For example, the cyanobacterial pigment zeaxanthin and the cryptophte pigment alloxanthin increased at Stickle Tarn (359% and 321% respectively) corresponding with the establishment of a dam at the outflow of the tarn in 1838. However, post-1900's the concentration of these pigments declined both at Stickle and at Easedale Tarn coincident with increased storm events and in the later decades of the century (~1980s onwards) decreases in acid deposition. In the lowland sites the cyanobacterial pigment aphanizophyll increased by 400-7000% and the indicator of total algal production β-carotene increased as much as six-fold indicating a substantial degradation in water quality and the onset of cyanobacterial blooms since the 1950's. In the lowland sites, degradation of water quality was closely linked to sewage installations and treatment work upgrades during the 1950's-70's and intensification of agricultural practices most notably increases in sheep stocking densities, which expanded in the 1950's. In lowland lakes with a higher

  7. Ecosystem Services Derived from Headwater Catchments

    EPA Science Inventory

    We used data from the USEPA’s wadeable streams assessment (WSA), US Forest Service’s forest inventory and analysis (FIA), and select USFS experimental forests (EF) to investigate potential ecosystems services derived from headwater catchments. C, N, and P inputs to these catchmen...

  8. Geomorphic histories for river and catchment management.

    PubMed

    Wasson, R J

    2012-05-13

    River and catchment management usually proceeds from the identification of an undesirable state (e.g. pollution, sedimentation, excessive water extraction, dams, invasion by exotic species) to a strategy for reaching a desirable state described as a target. Desirable states are usually determined from community values, economic assessments and ecosystem functions, or a combination of these. Where a catchment is highly disturbed, the target is usually not a natural state, as that cannot be achieved while maintaining human uses, and a history is needed to document the disturbance, understand its cause and define the 'existence space', that is, the range of natural states that have occurred in the past. Where a catchment is less disturbed, a former natural state could provide a target for management. But which of the many natural (equilibrium) states that have occurred in the past should be the target? The paper reviews what is known of the quantitative difference between pre- and post-disturbance states, searches for the presence or otherwise of equilibrium and comments on the utility of this information for catchment management. The focus is on erosion and sediment transport. PMID:22474683

  9. Measuring winter precipitation in a mountain catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring winter precipitation (principally snowfall) in a mountain catchment is difficult. The magnitude of gauge under catch is affected by variable density during deposition, wind speed and direction, and site conditions such as vegetation and topography. Though numerous studies have been condu...

  10. Simulating land use changes in the Upper Narew catchment using the RegCM model

    NASA Astrophysics Data System (ADS)

    Liszewska, Malgorzata; Osuch, Marzena; Romanowicz, Renata

    2010-05-01

    dataset and the Corine Land Cover programme (http://dataservice.eea.europa.eu/, GIOS, Poland). Simulations taking into account land use modifications in the catchment are compared with the reference simulations under no change in land use in the region. In the second part of the paper we discuss the application of the RegCM3 model in two climate change scenarios (SRES A2 and B1). The study is a contribution to the LUWR programme (http://luwr.igf.edu.pl).

  11. Catchments as Reactors: How do landscapes process diffuse pollution? (Invited)

    NASA Astrophysics Data System (ADS)

    Grathwohl, P.; Cirpka, O. A.

    2013-12-01

    Anthropogenic organic and inorganic compounds nowadays occur ubiquitous in soils, surface waters and groundwater. Emission of many pollutants is ongoing (through wastewater, agriculture, traffic, households, industry) but still the long-term fate of many compounds in the environment is unclear. Some are degraded by microorganisms, others accumulate in soils or biota, enter the food chain or are transported into groundwater systems and finally may occur in drinking water. Although much progress was made during the last 20 years concerning the identification and parameterization of many processes in laboratory experiments their interplay and efficiency at field scale in not clear. Very slow, but essential processes may have been overlooked - biodegradation may be very different in the lab compared to the field. Solute turnover often happens along steep biogeochemical gradients (locally small diffusion/dispersion coefficients) which are not well known under field conditions and which may dynamically shift their location depending on hydrology causing corresponding changes in concentrations. New field monitoring and analytical methods (sensors, time integrating passive samplers, non-target analysis, etc.) along with new tracer techniques are available meanwhile to record high frequency changes of major chemical parameters and to get an comprehensive inventory of compound classes at catchment scale. Fluxes of pollutants in contrasting catchments can be related to land use or degree of urbanization. Modeling of such systems is essential for exploration of future water quality scenarios for instance as a function of land use or climatic conditions. Spatially explicit reactive models based on coupled partial differential equations are hardly to handle on the scales requested. Conceptual models, however, cannot account for non-linear reactions. Therefore it remains a challenge to combine field observations and theories/models.

  12. Catchment scale afforestation for mitigating flooding

    NASA Astrophysics Data System (ADS)

    Barnes, Mhari; Quinn, Paul; Bathurst, James; Birkinshaw, Stephen

    2016-04-01

    After the 2013-14 floods in the UK there were calls to 'forest the uplands' as a solution to reducing flood risk across the nation. At present, 1 in 6 homes in Britain are at risk of flooding and current EU legislation demands a sustainable, 'nature-based solution'. However, the role of forests as a natural flood management technique remains highly controversial, due to a distinct lack of robust evidence into its effectiveness in reducing flood risk during extreme events. SHETRAN, physically-based spatially-distributed hydrological models of the Irthing catchment and Wark forest sub-catchments (northern England) have been developed in order to test the hypothesis of the effect trees have on flood magnitude. The advanced physically-based models have been designed to model scale-related responses from 1, through 10, to 100km2, a first study of the extent to which afforestation and woody debris runoff attenuation features (RAFs) may help to mitigate floods at the full catchment scale (100-1000 km2) and on a national basis. Furthermore, there is a need to analyse the extent to which land management practices, and the installation of nature-based RAFs, such as woody debris dams, in headwater catchments can attenuate flood-wave movement, and potentially reduce downstream flood risk. The impacts of riparian planting and the benefits of adding large woody debris of several designs and on differing sizes of channels has also been simulated using advanced hydrodynamic (HiPIMS) and hydrological modelling (SHETRAN). With the aim of determining the effect forestry may have on flood frequency, 1000 years of generated rainfall data representative of current conditions has been used to determine the difference between current land-cover, different distributions of forest cover and the defining scenarios - complete forest removal and complete afforestation of the catchment. The simulations show the percentage of forestry required to have a significant impact on mitigating

  13. Can spatial study of hydrological connectivity explain some behaviors of catchments?

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent

    2015-04-01

    Erosion is a major threat to European soil. Consequences can be very important both on-site and off-site. Belgian loamy soils are highly vulnerable to this threat because of their natural sensitivity to erosion on the one hand, and because the land is mainly used for intensive agricultural practices on the other hand. Over the last few decades, rising erosion has even been observed in our regions. This shows the importance of a deeper understanding of the coupled phenomena of runoff and erosion in order to manage soils at catchment scale. Plenty of research have already studied this but all agree to say that it seems to have a non-linear relationship between rainfall and discharge, as well as between rainfall and erosion. For that reason, a new concept has been developed a few years ago: the hydrological connectivity. Several research have focused on connectivity but up to now, each there are as much definition as papers. In this thesis, it will be important firstly to resume all these definitions to clarify this concept. Secondly, a methodology using various transects on the watershed and some pertinent field measurements will be used. These measurements include spatial distribution of particle size, surface states and soil moisture. A new approach of photogrammetry using an UAV will be used to observe erosion and deposition zones on the watershed. In this framework, several time scales will be studied from the event scale to the annual scale passing by monthly and seasonal scales. All this will serve to progress toward a better understanding of the concept of hydrological connectivity in order to study erosion at catchment scale. The final goal of this study is to describe hydrologically each different part of the catchment and to generalize these behaviors to other catchments with similar properties if possible. Afterwards, this research will be integrated in an existing (or not) model to improve the modelling of discharge and erosion in the catchment. Thanks to

  14. Spatialised fate factors for nitrate in catchments: modelling approach and implication for LCA results.

    PubMed

    Basset-Mens, Claudine; Anibar, Lamiaa; Durand, Patrick; van der Werf, Hayo M G

    2006-08-15

    The challenge for environmental assessment tools, such as Life Cycle Assessment (LCA) is to provide a holistic picture of the environmental impacts of a given system, while being relevant both at a global scale, i.e., for global impact categories such as climate change, and at a smaller scale, i.e., for regional impact categories such as aquatic eutrophication. To this end, the environmental mechanisms between emission and impact should be taken into account. For eutrophication in particular, which is one of the main impacts of farming systems, the fate factor of eutrophying pollutants in catchments, and particularly of nitrate, reflects one of these important and complex environmental mechanisms. We define this fate factor as: the ratio of the amount of nitrate at the outlet of the catchment over the nitrate emitted from the catchment's soils. In LCA, this fate factor is most often assumed equal to 1, while the observed fate factor is generally less than 1. A generic approach for estimating the range of variation of nitrate fate factors in a region of intensive agriculture was proposed. This approach was based on the analysis of different catchment scenarios combining different catchment types and different effective rainfalls. The evolution over time of the nitrate fate factor as well as the steady state fate factor for each catchment scenario was obtained using the INCA simulation model. In line with the general LCA model, the implications of the steady state fate factors for nitrate were investigated for the eutrophication impact result in the framework of an LCA of pig production. A sensitivity analysis to the fraction of nitrate lost as N(2)O was presented for the climate change impact category. This study highlighted the difference between the observed fate factor at a given time, which aggregates both storage and transformation processes and a "steady state fate factor", specific to the system considered. The range of steady state fate factors obtained for

  15. Inferring the effect of catchment complexity on mesoscale hydrologic response

    NASA Astrophysics Data System (ADS)

    FröHlich, Holger L.; Breuer, Lutz; Vaché, Kellie B.; Frede, Hans-Georg

    2008-09-01

    The effect of catchment complexity on hydrologic and hydrochemical catchment response was characterized in the mesoscale Dill catchment (692 km2), Germany. This analysis was developed using multivariate daily stream concentration and discharge data at the basin outlet, in connection with less frequently sampled catchment-wide end-member chemistries. The link between catchment-wide runoff sources and basin output was observed through a combination of concentration-discharge (C-Q) analysis and multivariate end-member projection. Subsurface stormflow, various groundwater and wastewater sources, as well as urban surface runoff emerged in catchment output chemistry. Despite the identification of multiple sources, several runoff sources observed within the catchment failed to display consistent links with the output chemistry. This failure to associate known source chemistry with outlet chemistry may have resulted from a lack of hydraulic connectivity between sources and basin outlet, from different arrival times of subbasin-scale runoff contributions, and also from an overlap of source chemistries that subsumed discrete runoff sources in catchment output. This combination of catchment heterogeneity and complexity simply suggests that the internal spatial organization of the catchment impeded the application of lumped mixing calculations at the 692 km2 outlet. Given these challenges, we suggest that in mesoscale catchment research, the potential effects of spatial organization should be included in any interpretation of highly integrated response signals, or when using those signals to evaluate numerical rainfall-runoff models.

  16. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    NASA Astrophysics Data System (ADS)

    Heinz, I.

    2007-06-01

    This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD) and the reform of the Common Agricultural Policy (CAP) require new approaches in water management. As many case studies have shown, co-operative agreements (CAs) between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i) water companies are ready to advise and financially support farmers in changing production methods; ii) changes of farming practices are tailored to the site-specific requirements; iii) farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv) voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it can be assumed