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1

Impacts of Urbanization on Groundwater Quality and Recharge in a Semi-arid Alluvial Basin  

Technology Transfer Automated Retrieval System (TEKTRAN)

The management of groundwater resources is paramount in semi-arid regions experiencing urban development. In the southwestern United States, enhancing recharge of urban storm runoff has been identified as a strategy for augmenting groundwater resources. An understanding of how urbanization may impac...

2

Geomorphology-based index for detecting minimal flood stages in arid alluvial streams  

NASA Astrophysics Data System (ADS)

Identification of a geomorphic index to represent lower thresholds for minor flows in ephemeral, alluvial streams in arid environments is an essential step as a precursor for reliable flash flood hazard estimations and establishing flood warning systems. An index, termed Alluvial wadi Flood Incipient Geomorphologic Index (AFIG), is presented. Analysis of data from an extensive field survey in the arid ephemeral streams in southern and eastern Israel was conducted to investigate the AFIG and the control over its value across the region. During the survey we identified distinguishable flow marks in the lower parts of streams' banks, such as niches, vegetation line, and change in bank material, which are indicative of low flows. The cross-sectional characteristics of the AFIG were studied in relationship with contributing drainage basin characteristics such as lithology, topography, and precipitation. Drainage area and hardness of the exposed lithology (presented as a basin-wide index) are the preferred descriptors to be used in estimating a specific AFIG in unsurveyed sites. Analyses of discharge records from seven hydrometric stations indicate that the recurrence interval of the determined AFIG is equal to or more frequent than 0.5 yr.

Shamir, E.; Ben-Moshe, L.; Ronen, A.; Grodek, T.; Enzel, Y.; Georgakakos, K. P.; Morin, E.

2013-03-01

3

Geomorphology-based index for detecting minimal flood stages in arid alluvial streams  

NASA Astrophysics Data System (ADS)

Identification of a geomorphic index to represent lower thresholds for minor flows in ephemeral, alluvial streams in arid environments is an essential step in reliable flash flood hazard estimations and establishing flood warning systems. An index, termed Alluvial wadi Flood Incipient Geomorphologic Index (AFIG), is presented. Analysis of data from an extensive field survey in the arid ephemeral streams in Southern and Eastern Israel was conducted to investigate the AFIG and the control over its value across the region. During the survey we identified distinguishable flow marks in the lower parts of streams' banks, such as niches, vegetation line, and change in bank material, which are indicative of low flows. The cross-sectional characteristics of the AFIG were studied in relationship with contributing drainage basin characteristics such as lithology, topography, and precipitation. Drainage area and hardness of the exposed lithology (presented as a basin-wide index) are the preferred descriptors to be used in estimating a specific AFIG in un-surveyed sites. Analyses of discharge records from seven hydrometric stations indicate that the recurrence interval of the determined AFIG is equal to or more frequent than 0.5 yr.

Shamir, E.; Ben-Moshe, L.; Ronen, A.; Grodek, T.; Enzel, Y.; Georgakakos, K.; Morin, E.

2012-11-01

4

Characterizing arid region alluvial fan surface roughness with airborne laser swath mapping digital topographic data  

Microsoft Academic Search

Range-front alluvial fan deposition in arid environments is episodic and results in multiple fan surfaces and ages. These distinct landforms are often defined by descriptions of their surface morphology, desert varnish accumulation, clast rubification, desert pavement formation, soil development, and stratigraphy. Although quantifying surface roughness differences between alluvial fan units has proven to be difficult in the past, high-resolution airborne

Kurt L. Frankel; James F. Dolan

2007-01-01

5

Late Quaternary landscape evolution in the Kunlun Mountains and Qaidam Basin, Northern Tibet: A framework for examining the links between glaciation, lake level changes and alluvial fan formation  

Microsoft Academic Search

The Qaidam Basin in Northern Tibet is one of the largest hyper-arid intermontane basins on Earth. Alluvial fans, pediment surfaces, shorelines and a thick succession of sediments within the basin, coupled with moraines and associated landforms in the adjacent high mountain catchments of the Kunlun Mountains, record a complex history of Late Quaternary paleoenvironmental change and landscape evolution. The region

Lewis A. Owen; Robert C. Finkel; M. Haizhou; Patrick L. Barnard

2006-01-01

6

Characterizing arid region alluvial fan surface roughness with airborne laser swath mapping digital topographic data  

NASA Astrophysics Data System (ADS)

Range-front alluvial fan deposition in arid environments is episodic and results in multiple fan surfaces and ages. These distinct landforms are often defined by descriptions of their surface morphology, desert varnish accumulation, clast rubification, desert pavement formation, soil development, and stratigraphy. Although quantifying surface roughness differences between alluvial fan units has proven to be difficult in the past, high-resolution airborne laser swath mapping (ALSM) digital topographic data are now providing researchers with an opportunity to study topography in unprecedented detail. Here we use ALSM data to calculate surface roughness on two alluvial fans in northern Death Valley, California. We define surface roughness as the standard deviation of slope in a 5-m by 5-m moving window. Comparison of surface roughness values between mapped fan surfaces shows that each unit is statistically unique at the 99% confidence level. Furthermore, there is an obvious smoothing trend from the presently active channel to a deposit with cosmogenic 10Be and 36Cl surface exposure ages of ˜70 ka. Beyond 70 ka, alluvial landforms become progressively rougher with age. These data suggest that alluvial fans in arid regions smooth out with time until a threshold is crossed where roughness increases at greater wavelength with age as a result of surface runoff and headward tributary incision into the oldest surfaces.

Frankel, Kurt L.; Dolan, James F.

2007-06-01

7

Extraction of fluvial networks from SPOT panchromatic data in a low relief, arid basin  

Microsoft Academic Search

Euclidean distance classification of SPOT panchromatic data was used to delineate ephemeral, fluvial networks on low-relief, alluvial fan surfaces in an arid basin in the southwestern United States. The SPOT classified channel network was registered to a Universal Transverse Mercator (UTM) projection and compared to areas of channelized flow and a Strahler-ordered channel network extracted from U.S. Geological Survey 7½ minute

THOMAS W. GARDNER; KATHRYN F. CONNORS; Haiyan Hu

1989-01-01

8

Interaction of climate and tectonics upon alluvial architecture: Late Carboniferous-Early Permian sequences at the southern margin of the Pennine Basin, UK  

Microsoft Academic Search

Late Carboniferous (mid to late Westphalian D) to Early Permian strata of south Staffordshire, English Midlands were deposited on the margins of a foreland basin (Pennine Basin) during a period of increasing climatic aridity. Approximately 300–500 m of grey and red-bed alluvial sediments contain five vertically stacked facies associations, each with characteristic stratal architecture and palaeosols.The succession exhibits three orders

Brian W. Glover; John H. Powell

1996-01-01

9

Precambrian alluvial fan and braidplain sedimentation patterns: Example from the Mesoproterozoic Rjukan Rift Basin, southern Norway  

Microsoft Academic Search

An integrated approach of facies analysis, geochemistry and paleohydrology provides new insight into the sedimentology and paleogeography of alluvial sediments in the Precambrian. Here, alluvial fan and braidplain sedimentation patterns are documented in a Mesoproterozoic rift basin, called (known as) the Rjukan Rift Basin in southern Norway. The studied formation (Heddersvatnet Formation) consists of volcanoclastic breccias and conglomerates, cross-bedded sandstones

Juha Köykkä

2011-01-01

10

Water availability and use pilot; methods development for a regional assessment of groundwater availability, southwest alluvial basins, Arizona  

USGS Publications Warehouse

Executive Summary: Arizona is located in an arid to semiarid region in the southwestern United States and is one of the fastest growing States in the country. Population in Arizona surpassed 6.5 million people in 2008, an increase of 140 percent since 1980, when the last regional U.S. Geological Survey (USGS) groundwater study was done as part of the Regional Aquifer System Analysis (RASA) program. The alluvial basins of Arizona are part of the Basin and Range Physiographic Province and cover more than 73,000 mi2, 65 percent of the State's total land area. More than 85 percent of the State's population resides within this area, accounting for more than 95 percent of the State's groundwater use. Groundwater supplies in the area are expected to undergo further stress as an increasing population vies with the State's important agricultural sector for access to these limited resources. To provide updated information to stakeholders addressing issues surrounding limited groundwater supplies and projected increases in groundwater use, the USGS Groundwater Resources Program instituted the Southwest Alluvial Basins Groundwater Availability and Use Pilot Program to evaluate the availability of groundwater resources in the alluvial basins of Arizona. The principal products of this evaluation of groundwater resources are updated groundwater budget information for the study area and a proof-of-concept groundwater-flow model incorporating several interconnected groundwater basins. This effort builds on previous research on the assessment and mapping of groundwater conditions in the alluvial basins of Arizona, also supported by the USGS Groundwater Resources Program. Regional Groundwater Budget: The Southwest Alluvial Basins-Regional Aquifer System Analysis (SWAB-RASA) study produced semiquantitative groundwater budgets for each of the alluvial basins in the SWAB-RASA study area. The pilot program documented in this report developed new quantitative estimates of groundwater budget components using recent (2000-2007) data and methods of data analysis. Estimates of inflow components, including mountain-front recharge, incidental recharge from irrigation of agriculture, managed recharge from recharge facilities, interbasin underflow from upgradient basins, and streamflow losses, are quantified for recent time periods. Mountain-front recharge is the greatest inflow component to the groundwater system and was estimated using two methods: a basin characteristic model and new precipitation information used in a previously developed regression equation. Annual mountain-front recharge for the study area for 1940-2007 estimated by the two methods is 730,000 acre-ft for the basin characteristic model and 643,000 acre-ft for the regression equation, representing 1.5 percent and 1.3 percent of precipitation, respectively. Outflow components, including groundwater withdrawals, evapotranspiration, and interbasin flow to downgradient basins, are also presented for recent time periods. Groundwater withdrawals accounted for the largest share of the water budget, with nearly 2.4 million acre-ft per year withdrawn from the study area in recent years. Evapotranspiration from groundwater was estimated at nearly 1.3 million acre-ft per year for the study area using a newly developed method incorporating vegetation indices from satellite images and land cover information. For water-budget components with temporal variation that could be assessed from available data, estimates for intervening time periods since before development were also developed. An estimate of aquifer storage change, representing both gains to and losses from the groundwater system since before development, was derived for the most developed basins in the study area using available estimates of groundwater-level changes and storage coefficients. An overall storage loss of 74.5 million acre-ft was estimated for these basins within the study area. Demonstration

Tillman, Fred D; Cordova, Jeffrey T.; Leake, Stanley A.; Thomas, Blakemore E.; Callegary, James B.

2011-01-01

11

Late Quaternary alluvial fans and paleosols of the Kangra basin, NW Himalaya: Tectonic and paleoclimatic implications  

Microsoft Academic Search

The paper describes Late Quaternary pedosedimentary sequences of the alluvial fans from the Kangra basin of NW Himalayas for tectonic and paleoclimatic implications. In the proximal part of the Kangra basin three coalescing alluvial fans, namely Rait-Rihlu fans (~65 km2), Kangra fans (~200 km2), and Palampur fans (~170 km2) from west to east evolved due to reactivation of longitudinal and transverse faults and

P. Srivastava; M. K. Rajak; L. P. Singh

2009-01-01

12

Alluvial sedimentology of the Upper Pleistocene Hinuera formation, Hamilton Basin, New Zealand  

Microsoft Academic Search

The Upper Pleistocene HinueraFormation is an unconsolidated alluvial deposit, up to 90 m thick, underlying some 2000 km of the plains of the Hamilton Basin and the southern half of the Hauraki Lowland. The sediments have been studied in detail at 19 widely-spaced sections in Hamilton Basin. The most striking lithological features are their coarseness, acid volcanic composition, and abundant

Terry M. Hume; Alan M. Sherwood; Campbell S. Nelson

1975-01-01

13

Variation in sedimentology and architecture of Eocene alluvial strata, Wind River and Washakie basins, Wyoming  

SciTech Connect

Eocene continental, alluvial strata of the Wind River Formation (Wind River Basin) and the Cathedral Bluffs Member of the Wasatch Formation (Washakie basin) provide two examples of Laramide intermontane basin aggradation. These alluvial sediments primarily represent overbank flood deposits marginal to channel complexes. Their sedimentology and architecture, although grossly similar, appear to vary somewhat with proximity to Laramide uplifts. In both cases, repetitive sedimentation on the floodplain produced a succession of depositional couplets, each composed of a light-gray sand overlain by a red clay-rich silt or sand. The lower sands are tabular bodies that, near their distal margins, taper discernibly. They commonly display planar and ripple-drift laminations. Upper clay-rich layers, which are laminated, are also generally tabular. Those floodplain strata depositional proximal to Laramide uplifts show little evidence of scouring prior to deposition of the next, overlying couplet. Most of these sedimentary layers, therefore, are laterally continuous (up to 2 km). This alluvial architecture results in relatively uniform porosity laterally within depositional units but variable porosity stratigraphically through the sequence. In contrast, alluvial sediments deposited farther from the Laramide uplifts have undergone sporadic incision (either during rising flood stage or subsequently) followed by aggradation. As a result, many of these floodplain couplets are discontinuous laterally and, hence, exhibit large-scale lateral variability in porosity. Both alluvial sequences have undergone similar types and extents of burial diagenesis.

Patterson, P.E.; Larson, E.E. (Univ. of Colorado, Boulder (United States))

1991-03-01

14

A sustainable agricultural paradigm of mountain-basin systems in the northwestern arid zone of China  

NASA Astrophysics Data System (ADS)

The Mountain-Basin System(MBS) in the northwestern arid zone of China consists of mountain vegetation vertical belt system and concentric circular vegetation (geologic and geomorphic) system of desert basin. The MBS contains three "circles": mountain, pedimont fan and alluvial plain, including nine belts, they are alpine belt, montane forest-grassland belt, low-montane desert belt, gravel gobi desert belt, agricultural oasis, marginal belt of diluvial fan, alluvial desert plain, sandy desert belt, and lake. The above-mentioned zonation is the most essential existence and functional pattern of those precious natural resources. It is the presentation of an irresistible rule of the nature and, also, the guidance system of ecological conservation and land use. Basing on this foundation, a "mountain-oasis-ecotone-desert eco-productive paradigm"is proposed. The MBS is it"s basic frame. It"s driving forces are biogeochemical circulation, biogeophysic process, and biogeosocial interaction, which run through the whole system. Thus, the establishment of a sustainable agricultural system and an optimized land use and land cover structure and pattern, which aimed at ecological conservation may be possible.

Zhang, Xinshi

2003-07-01

15

Alluvial dolines in the central Ebro basin, Spain: a spatial and developmental hazard analysis  

Microsoft Academic Search

Alluvial dolines are abundant in Quaternary terraces and pediments overlying Neogene gypsum in the Zaragoza area (central Ebro basin). Spatial analysis and experimental simulation show that sulphate content in the groundwater, grain size of the detrital cover, topography of the Tertiary\\/Quaternary boundary, annual variation of the water table and thickness of the detrital cover are the main factors controlling their

María Asuncíon Soriano; JoséLuis Simón

1995-01-01

16

Ground-water quality in alluvial basins that have minimal urban development, south-central Arizona  

USGS Publications Warehouse

Ground-water quality data (1917-96) from 772 wells in 16 alluvial basins that have minimal urban development were used to determine the effect of nonurban factors on ground-water quality in south- central Arizona. Characterization of the spatial variability of ground-water quality within and among alluvial basins that have minimal urban development will provide a baseline to which water- quality problems associated with urbanization can be compared. Four water-type categories--calcium carbonate, calcium mixed anion, sodium carbonate, and sodium chloride--were used to classify the 13 alluvial basins for which adequate data were available. Ground-water quality was compared to U.S. Environmental Protaection Agency maximum contaminant levels for drinking water, depth of well, and depth to top of perforated interval for five alluvial basins that represented the four water-type categories. Exceedances of maximum contaminant levels for fluoride and nitrate occurred in three and four basins, respectively, of the five selected basins. Specific-conductance values for ground water in the five selected basins tend to increase in a northwesterly direction toward the central part of Arizona as the extent of evaporite deposits increases. The results of this study, which are part of the U.S. Geological Survey's National Water-Quality Assessment Program, can be used to determine the effects of urban land-use activities on ground-water quality in similar hydrogeologic conditions and may be the best indicator available for nonurban ground-water quality in the region.

Gellenbeck, Dorinda J.; Coes, Alissa L.

1999-01-01

17

Avulsion Clusters in Alluvial Systems: An Example of Large-Scale Self-Organization in Ancient and Experimental Basins  

Microsoft Academic Search

The stratigraphic record of at least some alluvial basins exhibits a spatial structure that may reflect long time- scale (103-105 yr in natural basins) autogenic organization of river avulsions. Current models of avulsion-dominated alluvial sequences emphasize the spatial and temporal distribution of coarse-grained channel-belt deposits amid fine-grained floodplain materials. These models typically assume that individual avulsions move, either randomly or

E. Hajek; P. Heller; S. Huzurbazar; B. Sheets; C. Paola

2006-01-01

18

Crop-tree interactions in alley cropping systems on alluvial soils of the Upper Amazon Basin  

Microsoft Academic Search

A crop\\/hedgerow interface design was used to test three leguminous species,Inga edulis, Leucaena leucocephala andErythrina sp., for their potential use for alley cropping on alluvial soils in the upper Amazon Basin. Prunings were applied as mulch at three rates 0, 3.3 and 6.7 Mg dry matter\\/ha\\/crop. Competition, crop yields, nutrient budgets, and weed control were monitored for three consecutive crops

A. Salazar; L. T. Szott; C. A. Palm

1993-01-01

19

Hydrogeochemical Indicators of Groundwater Flow Systems in the Yangwu River Alluvial Fan, Xinzhou Basin, Shanxi, China  

Microsoft Academic Search

Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow\\u000a systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater ?2H and ?18O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate

Dongmei Han; Xing Liang; Menggui Jin; Matthew J. Currell; Ying Han; Xianfang Song

2009-01-01

20

Hydrogeochemical indicators of groundwater flow systems in the Yangwu River alluvial fan, Xinzhou Basin, Shanxi, China.  

PubMed

Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater delta(2)H and delta(18)O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate during recharge in the area. Major ion chemistry, including rCa/rMg and rNa/rCl ratios, show that groundwater salinization is probably dominated by water-rock interaction (e.g., silicate mineral weathering, dissolution of calcite and dolomite and cation exchange) in the Yangwu River alluvial fan, and locally by intensive evapotranspiration in the Hutuo River valley. Cl and Sr concentrations follow an increasing trend in shallow groundwater affected by evaporation, and a decreasing trend in deep groundwater. (87)Sr/(86)Sr ratios reflect the variety of lithologies encountered during throughflow. The groundwater flow systems (GFS) of the Yangwu River alluvial fan include local and intermediate flow systems. Hydrogeochemical modeling results, simulated using PHREEQC, reveal water-rock interaction processes along different flow paths. This modeling method is more effective for characterizing flow paths in the intermediate system than in the local system. Artificial exploitation on groundwater in the alluvial fan enhances mixing between different groundwater flow systems. PMID:19548025

Han, Dongmei; Liang, Xing; Jin, Menggui; Currell, Matthew J; Han, Ying; Song, Xianfang

2009-06-23

21

Geologic Characterization of Young Alluvial Basin-Fill Deposits from Drill Hole Data in Yucca Flat, Nye County, Nevada.  

SciTech Connect

Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada, that has been the site of numerous underground nuclear tests; many of these tests occurred within the young alluvial basin-fill deposits. The migration of radionuclides to the Paleozoic carbonate aquifer involves passage through this thick, heterogeneous section of Tertiary and Quaternary rock. An understanding of the lateral and vertical changes in the material properties of young alluvial basin-fill deposits will aid in the further development of the hydrogeologic framework and the delineation of hydrostratigraphic units and hydraulic properties required for simulating ground-water flow in the Yucca Flat area. This report by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, presents data and interpretation regarding the three-dimensional variability of the shallow alluvial aquifers in areas of testing at Yucca Flat, data that are potentially useful in the understanding of the subsurface flow system. This report includes a summary and interpretation of alluvial basin-fill stratigraphy in the Yucca Flat area based on drill hole data from 285 selected drill holes. Spatial variations in lithology and grain size of the Neogene basin-fill sediments can be established when data from numerous drill holes are considered together. Lithologic variations are related to different depositional environments within the basin including alluvial fan, channel, basin axis, and playa deposits.

Donald S. Sweetkind; Ronald M. Drake II

2007-01-22

22

Overlapping of pedogenesis and meteoric diagenesis in distal alluvial and shallow lacustrine deposits in the Madrid Miocene Basin, Spain  

NASA Astrophysics Data System (ADS)

The Miocene distal alluvial fan and palustrine deposits of the Madrid Basin (Paracuellos de Jarama area) were examined to establish the sequence of its pedogenic diagenetic processes and the main factors controlling them. In this area the diagenetic processes operated not only on carbonates, as commonly studied, but also in high magnesium clays and opaline cherts. This paper provides a dynamic model for saline alkaline lake margins that complements the existing freshwater palustrine model. Three sections (BER, PEL and UPC) containing limestones, sepiolite, dolostones and opaline cherts were examined; these represent the entire transition from alluvial fan deposit to lake environment. The alluvial fan deposits (PEL section) show the most complex sequence of processes. After a weak edaphic imprint, the primary mudstone and siltstones are affected by silicification (opaline levels formed mainly by selective replacement of sepiolites) and later dolomitization. Several types of dolomite are present, rounded crystals, spherules and globular bodies being the most characteristic. In the ponds situated at the foot of the alluvial fans or in interfan areas, sepiolite precipitated within free water bodies (BER section) and an intense pedogenesis led to the formation of palustrine sepiolite deposits. Later, the intense silicification of the sepiolite produced lenticular opaline levels that were locally transformed to quartz by aging. In the shallow lakes (UPC section), palustrine limestones and sepiolite were deposited. The carbonates are partially affected by silicification, the sepiolite becoming completely silicified. The opaline levels clearly preserve the structure of the limestones and sepiolite host rocks. All the opaline levels show local aging processes. The silicification processes were different in the three settings due to the interplay of groundwater with sedimentary environments and facies. In the distal alluvial fan sediments of the PEL section, the initial host rock affected by silicification is not preserved due to the later dolomitization that erased both it and its textures. The silicification environment was therefore not easy to determine. In the BER and UPC section, the main silicification took place in groundwater-influenced environments but evidence was seen of cements and silicifications in vadose environments. In all study settings, the overlapping of pedogenic, vadose and groundwater processes was controlled by changes in the position of the water table. Four stages were concluded to explain the transformation from the primary deposits to the later dolomitization process and the formation of vadose cements. The majority of the silicifications seen occurred as responses to changes in the water table position linked to the aggradation of this closed basin. In all the studied environments, the sepiolite deposits were preferentially silicified; their fibrous structure and high absorption capacity helping to retain interstitial fluids. Moreover sepiolite and opal are stable under relatively similar geochemical conditions in arid environments. The dissolution of the sepiolite caused an increase in silica in the interstitial fluids, favouring silicification and ruling out the need of a biogenic source. The replacement of limestones by silica is usually driven by variations in pH and salinity, which are very common in surface environments such as shallow lakes and soils.

Bustillo, M. A.; Alonso-Zarza, A. M.

2007-06-01

23

Abo Formation alluvial facies and Associated Basin Fill, Sacramento Mountains, New Mexico  

SciTech Connect

Outcrops of the Abo Formation (Wolfcampian to early Leonardian age) in the Sacramento Mountains of south-central New Mexico record the evolution of a dry alluvial fan system as it was deposited off the pedernal uplift into the Orogrande basin. The location and orientation of present-day outcrops allow us to observe an inferred east-to-west transverse facies tract consisting of: (1) proximal alluvial fans (lower Abo), which are contiguous in places with underlying Laborcita Formation fan-deltaic sediments; (2) medial anastomosed streams (middle Abo); and (3) distal low-gradient mud-dominated flood basins characterized by either distributary streams (upper Abo) or clastic tidal flats (Lee Ranch Tongue of the Abo) with associated marine carbonates (Pendejo Tongue of the Hueco Formation). Tectonism in the Pedernal highlands, which climaxed during the Late Pennsylvanian, apparently continued well into the Wolfcampian in this region, as evidenced by a major basal Abo unconformity and distinct stacked megasequences of lower Abo alluvial fan lithofacies. However, by the middle Abo, tectonic activity had quiesced and the uplift began eroding and retreating to the north and east. By the late Abo, a pediment surface had formed that was subsequently onlapped by upper Abo and eventually Yeso Formation sediments.

Speer, S.W.

1986-03-01

24

Chronology and Archeology of Holocene Alluvial Archives in the Wadi Sbeïtla Basin, Central Tunisia  

NASA Astrophysics Data System (ADS)

A multidisciplinary study of Holocene alluvial archives in the Wadi Sbeïtla Basin revealed several phases of increased geomorphic activity, each followed by a stable environment and a soil formation phase. The alternate dynamic and stable phases are due to the past climatic fluctuations, superimposed by human activities. Using radiocarbon dating and archaeological study, we established a detailed chronostratigraphy of the Holocene alluvial records in the study area. Four important phases of deposition were dated: an early-Holocene phase (10-7 ka cal BP), a mid-Holocene phase (6-4 ka cal BP), a late Roman phase (1.6-1.4 ka cal BP) and a recent medieval phase (1-0.5 ka cal BP). A peak of fluvial activity took place during the Pleistocene-Holocene transition and in the late Roman crisis (around 1.6 ka cal BP). Two long periods of soil forming process were dated around the Capsian epoch (7 ka cal BP) and in the second half of the mid-Holocene (5-4 ka cal BP). Finally, immature alluvial soils were developed around 1.1 ka cal BP.

Zerai, K.

2009-04-01

25

Spatial and temporal characteristics of aridity conditions in Tarim Basin, China  

NASA Astrophysics Data System (ADS)

Arid ecosystems are very sensitive to a variety of physical, chemical and biological degradation processes. Tarim Basin, the biggest endorheic basin in the Central Asia continent, is considered as one of the least water-endowed regions in the world and arid and semi-arid environmental conditions are dominant. For the purposes of the convention, arid, semi-arid and dry sub-humid areas were defined as "areas, other than polar and sub-polar regions, in which the ratio of annual precipitation to potential evapotranspiration falls within the range from 0.05 to 0.65." In this study, the Aridity Index (AI), the ratio of precipitation and land surface temperature, was also adopted as the base method for determining dry land types and thereby delineating boundaries and showing changes of aridity conditions in Tarim Basin. Here, precipitation is from TRMM/PR, and land surface temperature is from Modis LST. To analyze the spatial and temporal variations of arid environmental conditions in Tarim basin, we calculated the yearly aridity index (the ratio of total yearly rainfall to yearly mean Land Surface Temperature) based on the accumulated monthly precipitation and the monthly Land Surface Temperature in growing season for the period 2000-2009. The results indicated it is possible to work out an aridity index map with more detailed spatial patterns, which is valuable for identifying human impacts by associated with vegetation and soil moisture characters.

Sun, Zhandong; Chang, Ni-Bin; Opp, Christian; Hennig, Thomas

2010-10-01

26

Source area and tectonic control on alluvial-fan development in the Miocene Fohnsdorf intramontane basin, Austria  

Microsoft Academic Search

Middle Miocene alluvial fans in the intramontane Fohnsdorf Basin of the Eastern Alps originated along normal faults and linked strike-slip faults in a continental half-graben setting. The fans display considerable facies differences. Debris flows of the Rachau fan are characterized by a sandy matrix and large boulders, whereas debris flows of the Apfelberg fan are characterized by higher silt and

MICHAEL WAGREICH; PHILIPP E. STRAUSS

2005-01-01

27

Relations between climatic variability and hydrologic time series from four alluvial basins across the southwestern United States  

Microsoft Academic Search

Hydrologic time series of groundwater levels, streamflow, precipitation, and tree-ring indices from four alluvial basins in the southwestern United States were spectrally analyzed, and then frequency components were reconstructed to isolate variability due to climatic variations on four time scales. Reconstructed components (RCs), from each time series, were compared to climatic indices like the Pacific Decadal Oscillation (PDO), North American

R. T. Hanson; M. D. Dettinger; M. W. Newhouse

2006-01-01

28

Impact and consequences of evapotranspiration changes on water resources availability in the arid Zhangye Basin, China  

Microsoft Academic Search

Evapotranspiration (ET) plays an important role in the hydrological cycle and it is essential to estimate ET accurately for the evaluation of available water resources. This is most important in arid and semi?arid regions. In this paper, the long?term changes in daily ET in the semi?arid Zhangye Basin in northwest China and its impact factors were studied. The spatial distribution

Xiaomei Jin; M. E. Schaepman; J. G. P. W. Clevers; Z. Bob Su

2009-01-01

29

Modern sediment yield compared to geologic rates of sediment production in a semi-arid basin, New Mexico: Assessing the human impact  

USGS Publications Warehouse

In the semi-arid Arroyo Chavez basin of New Mexico, a 2.28 km2 sub-basin of the Rio Puerco, we contrasted short-term rates (3 years) of sediment yield measured with sediment traps and dams with long-term, geologic rates (???10 000 years) of sediment production measured using 10Be. Examination of erosion rates at different time-scales provides the opportunity to contrast the human impact on erosion with background or geologic rates of sediment production. Arroyo Chavez is grazed and we were interested in whether differences in erosion rates observed at the two time-scales are due to grazing. The geologic rate of sediment production, 0-27 kg m-2 a -1 is similar to the modern sediment yields measured for geomorphic surfaces including colluvial slopes, gently sloping hillslopes, and the mesa top which ranged from 0.12 to 1.03 kg m -2 a-1. The differences between modern sediment yield and geologic rates of sediment production were most noticeable for the alluvial valley floor, which had modern sediment yields as high as 3.35 kg m-2 a-1. The hydraulic state of the arroyo determines whether the alluvial valley floor is aggrading or degrading. Arroyo Chavez is incised and the alluvial valley floor is gullied and piped and is a source of sediment. The alluvial valley floor is also the portion of the basin most modified by human disturbance including grazing and gas pipeline activity, both of which serve to increase erosion rates. ?? 2004 John Wiley and Sons, Ltd.

Gellis, A. C.; Pavich, M. J.; Bierman, P. R.; Clapp, E. M.; Ellevein, A.; Aby, S.

2004-01-01

30

Non-parametric trend analysis of the aridity index for three large arid and semi-arid basins in Iran  

NASA Astrophysics Data System (ADS)

Currently, an important scientific challenge that researchers are facing is to gain a better understanding of climate change at the regional scale, which can be especially challenging in an area with low and highly variable precipitation amounts such as Iran. Trend analysis of the medium-term change using ground station observations of meteorological variables can enhance our knowledge of the dominant processes in an area and contribute to the analysis of future climate projections. Generally, studies focus on the long-term variability of temperature and precipitation and to a lesser extent on other important parameters such as moisture indices. In this study the recent 50-year trends (1955-2005) of precipitation (P), potential evapotranspiration (PET), and aridity index (AI) in monthly time scale were studied over 14 synoptic stations in three large Iran basins using the Mann-Kendall non-parametric test. Additionally, an analysis of the monthly, seasonal and annual trend of each parameter was performed. Results showed no significant trends in the monthly time series. However, PET showed significant, mostly decreasing trends, for the seasonal values, which resulted in a significant negative trend in annual PET at five stations. Significant negative trends in seasonal P values were only found at a number of stations in spring and summer and no station showed significant negative trends in annual P. Due to the varied positive and negative trends in annual P and to a lesser extent PET, almost as many stations with negative as positive trends in annual AI were found, indicating that both drying and wetting trends occurred in Iran. Overall, the northern part of the study area showed an increasing trend in annual AI which meant that the region became wetter, while the south showed decreasing trends in AI.

Ahani, Hossien; Kherad, Mehrzad; Kousari, Mohammad Reza; van Roosmalen, Lieke; Aryanfar, Ramin; Hosseini, Seyyed Mashaallah

2013-05-01

31

Groundwater recharge and agricultural contamination in alluvial fan of Eastern Kofu basin, JAPAN  

NASA Astrophysics Data System (ADS)

Agriculture has significant effects on the rate and composition of groundwater recharge. The chemical loading into groundwater have been dominated by the constituents derived directly or indirectly from agricultural practices and additives. The contamination of groundwater with nitrate is a major public health and environmental concern around the world. The inorganic constituents like, K+, Ca2+, Mg2+, SO42-, Cl- and variety of other minor elements of groundwater are often used as agricultural additives; and the natural occurrence of these elements are dominated by the agricultural sources. A recent study has reported that Kofu basin groundwater aquifer is contaminated by nitrate from agricultural areas because of the fertilizer application for the orchard (Kazama and Yoneyama, 2002; Sakamoto et al., 1997, Nakamura et al., 2007). The water-oxygen and hydrogen stable isotope (?18O and ?D) and nitrate-nitrogen stable isotope (?15N) of groundwater, river water and precipitation samples were investigated to identify the source of groundwater and nitrate nitrogen contamination in groundwater in the Fuefukigawa and Hikawa_Kanegawa alluvial fans in Kofu basin. The plot of ?D versus ?18O values of groundwater, river water and precipitation samples suggest that the groundwater is a mixture of precipitation and river water. And nitrate-nitrogen isotope values have suggested the nitrate contamination of groundwater is from agricultural area. The study revealed positive correlation between groundwater ?18O values and NO3-, Cl-, SO42-, Ca2+, Mg2+ concentration, which shows the agricultural contamination is carried by the recharge of groundwater from precipitation in alluvial fan. Whereas, NO3-, Cl-, SO42-, Ca2+, Mg2+ are diluted by the river water recharges. This study showed the quality of groundwater is resulted from the mixing of water from the different source during the groundwater recharge in the study area. References Kazama F, Yoneyama M (2002) Nitrogen generation in the Yamanashi prefecture and its effects on the groundwater pollution. Int. Envir. Science Vol. 15:293-298. (in Japanese) Sakamoto Y, Nakamura F, Kazama F (1990) Spatial Distribution of Nitrate Concentration in Groundwater-Derived Potable. Reports of the Faculty of Engineering Yamanashi University Vol.41:139-144. (in Japanese) Nakamura T, Satake H, Kazama F (2007) Effects of groundwater recharge on nitrate-nitrogen loadings. Journal of Water and Environment Technology Vol.5:87-93.

Nakamura, T.

2009-12-01

32

Palaeohydrological and palaeoecological studies on South Cameroonian alluvial sedimentary basins - New evidence on the palaeoenvironmental evolution of western Central Africa since the Late Pleistocene  

NASA Astrophysics Data System (ADS)

A new valuable and innovative contribution will be presented to ascertain the timing and extension of climatic and ecological changes in western equatorial Africa. Main focus is laid on the dynamics of climate, fluvial systems and the high sensitive tropical ecosystems (dense evergreen and semi-deciduous rain forest and savanna-rain forest margin) since the Late Pleistocene (~50 kyrs. BP). For this purpose extended fieldworks were carried out in South Cameroon (2004-2008) by the ReSaKo-Project (sub-project of DFG-Project 510) with abundant investigations on alluvial sedimentary basins of equatorial tropical fluvial systems. Suitable alluvial sediment-archives for palaeoenvironmental research were uncovered along selected braiding, meandering and anabranching/anastomosing reaches of major southwestern, into the Gulf of Guinea (Ntem, Nyong and Sanaga) and southeastern, into the Congo basin (Boumba, Dja and Ngoko) draining rivers (RUNGE et al. 2006, SANGEN 2008). Among geomorphological investigations and cross section discussions, 150 corings (Edelman, 20 cm layers) reaching maximum depths of 550 cm were carried out on river benches, levees, cut-off and periodical branches, islands and terraces as well as in seasonal inundated floodplains and backswamps. Corresponding sedimentary profiles and catenae recovered multilayered, sandy to clayey alluvia containing sedimentary form-units and palaeosurfaces which contribute to the reconstruction of palaeoenvironmental conditions in western equatorial Africa. Several (59) radiocarbon (AMS) dated samples (Erlangen and Lecce) from fossil organic layers and macro-rests embedded in these units yielded Late Pleistocene to recent ages (14C-ages around 48 to 0.2 kyrs. BP), spanning also the Last Glacial Maximum (LGM) and Holocene record. Abrupt grain-size modifications and alternating form-units (sandy and clayey layers, palaeosurfaces) in the stratigraphic records display fluctuations in the fluvial-morphological response of the fluvial systems to climatic variability and other extrinsic and intrinsic impacts. Although the sedimentary record varies among the studied river reaches, fossil organic sediment layers (palaeosurfaces) containing valuable proxy data were found in almost all alluvia basins of examined southern Cameroonian rivers. Around 56 ^13C-values corresponding to the dated samples (-31.4 to -18.0 ) evidence that despite major disturbances of the African rain forest over geological times (MALEY 2001) mainly rain forest ecosystems have prevailed during the corresponding time periods, presumably as gallery forests, which were able to persist in this fluvial habitat ("fluvial refuge"), even during arid periods (e.g. LGM). The results are consistent with earlier findings from lacustrine (SERVANT & SERVANT-VILDARY 2000), marine (WELDEAB et al. 2007) and additional sediment archives (GASSE et al. 2008) and will add additional insights and information to the unravelling of the complex respond of the African monsoon, the Central African ecosystems and fluvial systems to Late Quaternary climatic and environmental fluctuations within a globally teleconnected system. References: GASSE, F., CHALIé, F., VINCENS, A., WILLIAMS, M.A.J. & WILLIAMSON, D. (2008): Climatic patterns in equatorial and southern Africa from 30,000 to 10,000 years ago reconstructed from terrestrial and near-shore proxy data. Quaternary Science Reviews, 27 (25-26), 2316-2340. MALEY, J. (2001): The impact of arid phases on the African rain forest through geological history. In: WEBER, W., WHITE, L., VEDDER, A., NAUGHTON-TREVES, L. (Eds.): African rain forest ecology and conservation - An interdisciplinary perspective. Yale University Press, New Haven, 68-87. RUNGE, J., EISENBERG, J., SANGEN, M. (2006): Geomorphic evolution of the Ntem alluvial basin and physiogeographic evidence for Holocene environmental changes in the rain forest of SW Cameroon (Central Africa) - preliminary results. Z. Geomorph. N.F., Suppl. Bd. 145, 63-79. SERVANT, M. & SERVANT-VILDARY, S. (2000): Dynamique à long terme des

Sangen, M.

2009-04-01

33

Hydrogeology and simulation of flow between the alluvial and bedrock aquifers in the upper Black Squirrel Creek basin, El Paso County, Colorado  

USGS Publications Warehouse

Anticipated increases in pumping from the bedrock aquifers in El Paso County potentially could affect the direction and rate of flow between the alluvial and bedrock aquifers and lower water levels in the overlying alluvial aquifer. The alluvial aquifer underlies about 90 square miles in the upper Black Squirrel Creek Basin of eastern El Paso County. The alluvial aquifer consists of unconsolidated alluvial deposits that unconformably overlie siltstones, sandstones, and conglomerate (bedrock aquifers) and claystone, shale, and coal (bedrock confining units) of the Denver Basin. The bedrock aquifers (Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers) are separated by confining units (upper and lower Denver and the Laramie confining units) and overlie a relatively thick and impermeable Pierre confining unit. The Pierre confining unit is assumed to be a no-flow boundary at the base of the alluvial/ bedrock aquifer system. During 1949-90, substantial water-level declines, as large as 50 feet, in the alluvial aquifer resulted from withdrawals from the alluvial aquifer for irrigation and municipal supplies. Average recharge to the alluvial aquifer from infiltration of precipitation and surface water was an estimated 11.97 cubic feet per second and from the underlying bedrock aquifers was an estimated 0.87 cubic foot per second. Water-level data from eight bedrock observation wells and eight nearby alluvial wells indicate that, locally, the alluvial and bedrock aquifers probably are hydraulically connected and that the alluvial aquifer in the upper Black Squirrel Creek Basin receives recharge from the Denver and Arapahoe aquifers but-locally recharges the Laramie-Fox Hills aquifer. Subsurface-temperature profiles were evaluated as a means of estimating specific discharge across the bedrock surface (the base of the alluvial aquifer). However, assumptions of the analytical method were not met by field conditions and, thus, analyses of subsurface-temperature profiles did not reliably estimate specific discharge across the bedrock surface. The vertical hydraulic diffusivity of a siltstone and sandstone in the lower Denver confining unit was estimated, by an aquifer test, to be about 8 x 10'4 square foot per day. Physical and chemical characteristics of water from the bedrock aquifers in the study area generally differ from the physical and chemical characteristics of water from the alluvial aquifer, except for the physical and chemical characteristics of water from one bedrock well, which is completed in the Laramie-Fox Hills aquifer. In the southern part of the study area, physical and chemical characteristics of ground water indicate downward flow of water from the alluvial aquifer to the Laramie-Fox Hills aquifer. A three-dimensional numerical model was used to evaluate flow of water between the alluvial aquifer and underlying bedrock. Simulation of steady-state conditions indicates that flow from the bedrock aquifers to the alluvial aquifer was about 7 percent of recharge to the alluvial aquifer, about 0.87 cubic foot per second. The potential effects of withdrawal from the alluvial and bedrock aquifers at estimated (October 1989 to September 1990) rates and from the bedrock aquifers at two larger hypothetical rates were simulated for a 50-year projection period. The model simulations indicate that water levels in the alluvial aquifer will decline an average of 8.6 feet after 50 years of pumping at estimated October 1989 to September 1990 rates. Increases in withdrawals from the bedrock aquifers in El Paso County were simulated to: (1) Capture flow that currently discharges from the bedrock aquifers to springs and streams in upland areas and to the alluvial aquifer, (2) induce flow downward from the alluvial aquifer, and (3) accelerate the rate of waterlevel decline in the alluvial aquifer.

Watts, K. R.

1995-01-01

34

Avulsion Clusters in Alluvial Systems: An Example of Large-Scale Self-Organization in Ancient and Experimental Basins  

NASA Astrophysics Data System (ADS)

The stratigraphic record of at least some alluvial basins exhibits a spatial structure that may reflect long time- scale (103-105 yr in natural basins) autogenic organization of river avulsions. Current models of avulsion-dominated alluvial sequences emphasize the spatial and temporal distribution of coarse-grained channel-belt deposits amid fine-grained floodplain materials. These models typically assume that individual avulsions move, either randomly or deterministically, to low spots distributed throughout the model space. However, our observations of ancient deposits and experimental stratigraphy indicate a previously unrecognized pattern of channel-belt organization, where clusters of closely-spaced channel-belt deposits are separated from each other by extensive intervals of overbank deposits. We explore potential causes of and controls on avulsion clustering with outcrop and subsurface data from Late Cretaceous/Early Paleogene fluvial deposits in the Rocky Mountains (including the Ferris, Lance, and Fort Union formations of Wyoming) and results of physical stratigraphy experiments from the St. Anthony Falls Lab, University of Minnesota. We use Ripley's K-function to determine the degree and scales of clustering in these basins with results that show moderate statistical clustering in experimental deposits and strong clustering in the Ferris Formation (Hanna Basin, Wyoming). External controls (base level, subsidence rate, and sediment/water supplies) were not varied during the experiment, and therefore not factors in cluster formation. Likewise, the stratigraphic context of the ancient system (including the absence of incised valleys and lack of faulting) suggests that obvious extrinsic controls, such as base level change and local tectonics, were not major influences on the development of clusters. We propose that avulsion clusters, as seen in this study, reflect a scale of self-organization in alluvial basins that is not usually recognized in stratigraphy. However cursory examination of other ancient systems suggests that such structure may be common in the rock record. Understanding mechanisms driving avulsion clustering will shed light on the dominant processes in alluvial basins over long time scales. Furthermore, characterizing autogenic avulsion clusters will be an important factor to consider when interpreting allogenic signals in ancient basin fills.

Hajek, E.; Heller, P.; Huzurbazar, S.; Sheets, B.; Paola, C.

2006-12-01

35

Hydrogeologic features of the alluvial deposits in the Greybull River valley, Bighorn Basin, Wyoming  

USGS Publications Warehouse

The alluvial aquifer along the Greybull River in Wyoming, consists principally of the Greybull terrace doposits and flood-plain alluvium but also includes Burlington terrace deposits east of Burlington, the McKinnie terrace, and the younger, generally undissected alluvial-fan deposits. Well-log data and 18 surface-resistivity measurements at four localities indicate that the thickness of the alluvial aquifer is as much as 60 feet thick only near Burlington and Otto. The most favorable area for development of ground water from the alluvial aquifer is near Burlington and Otto where relatively large amounts of water can be obtained from the Greybull terrace deposits and the flood-plain alluvium. Elsewhere, the deposits of the alluvial aquifer yield only small amounts of water to wells. (Woodard-USGS)

Cooley, M. E.; Head, W. J.

1979-01-01

36

The rate of iron oxide enrichment in arid zone alluvial fan soils, Tunisian southern atlas, measured by mineral magnetic techniques  

Microsoft Academic Search

Rates of iron oxide enrichment of soils on a segmented alluvial fan in southern Tunisia are examined. Mineral magnetic and chemical characteristics of soils developed on two dated relict segments and on contemporary alluvium suggest that the rate of Fe-oxide enrichment was more rapid in the Holocene (2.6 × 10?8 g g?1 yr?1 over the last 5000 years) than in

Kevin White; John Walden

1997-01-01

37

RESERVOIR ARCHITECTURE IN A TERMINAL ALLUVIAL PLAIN: AN OUTCROP ANALOGUE STUDY (UPPER TRIASSIC, SOUTHERN GERMANY) PART II: CYCLICITY, CONTROLS AND MODELS  

Microsoft Academic Search

This outcrop analogue study investigates Triassic fluvial sandstones of the Stubensandstein Formation which were deposited on a terminal alluvial plain under semi- arid to sub-humid climatic conditions in the land-locked South German Keuper Basin. The Stubensandstein may serve as an analogue for reservoir units in comparable continental basins. Data came from studies of 13 large sandpits, together with a subsurface

J. Hornung; T. Aigner

2002-01-01

38

High-resolution magnetic stratigraphy across the Oligocene-Miocene boundary in an alluvial-lacustrine succession (Ebro Basin, northeast Spain)  

Microsoft Academic Search

The study of a late Oligocene-early Miocene, 300 m thick section of alluvial and shallow lacustrine sediments in the Ebro Basin, has allowed a high-resolution magnetic polarity stratigraphy for the Oligocene-Miocene boundary to be established. The samples studied include alluvial sandstones and mudstones as well as shallow lacustrine and paludine, micritic and microsparitic limestones. Two-hundred-and-fifty specimens were stepwise thermally or

X. Barberà; J. M. Parés; L. Cabrera; P. Anadón

1994-01-01

39

Sediment redistribution due to a dense reservoir network in a large semi-arid Brazilian basin  

Microsoft Academic Search

This paper investigates for a 25-year period the sediment distribution in a semi-arid Brazilian basin (2 × 10 km) with a network containing more than 4000 surface reservoirs. The methodology is based on rating curves and fitted parameters derived from field data. The results showed that suspended load corresponded to 70% of the total sediment yield (148 t km year).

Mário Cesar Wiegand; José Carlos de Araújo

2011-01-01

40

Hydrogeologic features of the alluvial deposits in the Owl Creek Valley, Bighorn Basin, Wyoming  

USGS Publications Warehouse

The alluvial acquifer principally of the flood-plain alluvium and part of the Arapahoe Ranch terrace deposits and consists subordinately of alluvial-fan deposits. Thickness of the alluvial aquifer is generally 20 to 40 feet. Dissolved-solids concentration of water in the alluvial aquifer ranges from about 500 to more than 3,000 milligrams per liter. The most favorable areas for groundwater development are the flood-plain alluvium and part of the Arapahoe Ranch terrace deposits; however, in much of these units, the water contains more than 2,000 milligrams per liter of dissolved solids. Measurements of specific conductance of the flow of Owl Creek indicate a progressive increase in the down stream direction and range between 15 and 355 micromhos per centimeter at 25C per mile. The increases are due to return flow of irrigation water, inflow from tributaries, and inflow from groundwater. Conspicuous terraces in Owl Creek Valley included an unnamed terrace at 500 feet above Owl Creek, the Embar Ranch terrace 160 to 120 feet above the creek, and the Arapahoe Ranch terrace 50 to 20 feet above the creek. (USGS)

Cooley, M. E.; Head, W. J.

1982-01-01

41

Estimation of groundwater pumping as closure to the water balance of a semi-arid, irrigated agricultural basin  

Microsoft Academic Search

Groundwater pumping is frequently the least measured water balance component in semi-arid basins with significant agricultural production. In this article, we develop a GIS-based water balance model for estimating basin-scale monthly and annual groundwater pumping and apply it to a 2300 km2 semi-arid, irrigated agricultural area in the southern San Joaquin Valley, California. Both, annual groundwater storage changes and pumping

Nels Ruud; Thomas Harter; Alec Naugle

2004-01-01

42

Drainage Basin Influences on Alluvial Fan Processes in the Lost River Range, Idaho  

Microsoft Academic Search

by many large (radius > 5 km) low angle (2-3 degree) alluvial fans developed across and beyond the ~140 km active Lost River normal fault (Crone et al., 1987). Stratigraphic exposures of fan sediments reveal these large fans are sheetflood-dominated (Patterson, 2006). Preliminary field observations indicate ~20-30 cm thick couplets of alternating ~5-15 cm and ~2-5 cm sub-angular, imbricated limestone-dominated

Michael Poulos

2009-01-01

43

Distribution of bedrock and alluvial channels in forested mountain drainage basins  

Microsoft Academic Search

MOUNTAIN river networks often consist of both bedrock and alluvial channels1-5, the spatial distribution of which controls several fundamental geomorphological and ecological processes6,7. The nature of river channels can influence the rates of river incision and landscape evolution1,2, as well as the stream habitat characteristics affecting species abundance and aquatic ecosystem structure8-11. Studies of the factors controlling the distribution of

David R. Montgomery; Tim B. Abbe; John M. Buffington; N. Phil Peterson; Kevin M. Schmidt; Jonathan D. Stock

1996-01-01

44

Space time distribution of ancient and active alluvial karst subsidence: examples from the central Ebro Basin, Spain  

NASA Astrophysics Data System (ADS)

Space and time variations of alluvial karst subsidence in the central Ebro Basin are analysed in trenches (paleodolines), aerial photographs (historical dolines) and field surveys (present-day active dolines). The measured subsidence rates, as well as a comparison between densities of paleodolines computed in randomly selected scan-lines and density of active dolines computed in maps, suggest that present-day subsidence in favourable areas is more intense than that of Pleistocene times. According to diachronic maps drawn from (a) different aerial photographs taken after 1946 and (b) field surveys on deformations in urbanized areas, subsidence behaved as a nearly steady process while the whole area was used for agriculture. In contrast, rapid changes (through periods of several tens of years) have occurred in urbanized areas, in which dolines expand their boundaries through small marginal collapses, shifting sharply their sinking centres to neighbouring sites. These rapid changes do not have an equivalent in observed paleodolines.

Simón, J. L.; Soriano, M. A.; Arlegui, L. E.; Gracia, J.; Liesa, C. L.; Pocoví, A.

2008-01-01

45

Tectonic significance of Upper Cretaceous alluvial-fan deposits in the Peninsular Ranges forearc basin complex, Baja California (Mexico)  

SciTech Connect

Recent evidence suggests that forearc basins, previously depicted as broad downwarps, may experience syndepositional faulting and/or folding. The upper Campanian El Gallo Formation, which was deposited along the northern margin of the Rosario embayment of the peninsula Ranges forearc basin complex, records tilting of the underlying arc massif basement contemporaneous with dissection of the arc source terrane. The La Escarpa member at the base of the El Gallo Formation consists of a 100-180-m thick upward-fining sequence, interpreted as a retrogradational proximal to distal alluvial-fan deposit. Overlying the La Escarpa member is the 1,000-m thick El Disecado member, which lies at the top of the El Gallo Formation and consists of sandy fluvial deposits. Conglomerate clast counts from the La Escarpa member and point-count data from sandstones throughout the El Gallo Formation show an upsection increase in granitic and metasedimentary rock fragments relative to volcanic/metavolcanic rock fragments, reflecting unroofing and progressive headward erosion of the source terranes in the Peninsular Ranges. Paleocurrent data from the La Escarpa and El Disecado members suggest a rotation of approximately 110{degree} with time, from west-northwesterly to southerly, reflecting tilting of the basin floor. This may have been accomplished by downdropping along an east-west-trending fault that divided the Rosario embayment into separate subbasins during the Cretaceous.

Fulford, M.; Busby-Spera, C. (Univ. of California, Santa Barbara (USA))

1990-05-01

46

Late Quaternary arid\\/humid cycles in the Mojave Desert and western Great Basin of North America  

Microsoft Academic Search

This paper discusses the late Quaternary environmental changes that occurred in the drylands of western North America, with particular emphasis on the aeolian\\/lacustrine record from the Mojave Desert. The Basin and Range Province (which includes the Great Basin and the Mojave, Sonoran and Chihuahuan deserts), the primary physiographic region within the North American arid zone, is characterized by a wide

V. P Tchakerian; N Lancaster

2002-01-01

47

Revisiting a classification scheme for U.S.-Mexico alluvial basin-fill aquifers.  

PubMed

Intermontane basins in the Trans-Pecos region of westernmost Texas and northern Chihuahua, Mexico, are target areas for disposal of interstate municipal sludge and have been identified as possible disposal sites for low-level radioactive waste. Understanding ground water movement within and between these basins is needed to assess potential contaminant fate and movement. Four associated basin aquifers are evaluated and classified; the Red Light Draw Aquifer, the Northwest Eagle Flat Aquifer, the Southeast Eagle Flat Aquifer, and the El Cuervo Aquifer. Encompassed on all but one side by mountains and local divides, the Red Light Draw Aquifer has the Rio Grande as an outlet for both surface drainage and ground water discharge. The river juxtaposed against its southern edge, the basin is classified as a topographically open, through-flowing basin. The Northwest Eagle Flat Aquifer is classified as a topographically closed and drained basin because surface drainage is to the interior of the basin and ground water discharge occurs by interbasin ground water flow. Mountains and ground water divides encompass this basin aquifer on all sides; yet, depth to ground water in the interior of the basin is commonly >500 feet. Negligible ground water discharge within the basin indicates that ground water discharges from the basin by vertical flow and underflow to a surrounding basin or basins. The most likely mode of discharge is by vertical, cross-formational flow to underlying Permian rocks that are more porous and permeable and subsequent flow along regional flowpaths beneath local ground water divides. The Southeast Eagle Flat Aquifer is classified as a topographically open and drained basin because surface drainage and ground water discharge are to the adjacent Wildhorse Flat area. Opposite the Eagle Flat and Red Light Draw aquifers is the El Cuervo Aquifer of northern Chihuahua, Mexico. The El Cuervo Aquifer has interior drainage to Laguna El Cuervo, which is a phreatic playa that also serves as a focal point of ground water discharge. Our evidence suggests that El Cuervo Aquifer may lose a smaller portion of its discharge by interbasin ground water flow to Indian Hot Springs, near the Rio Grande. Thus, El Cuervo Aquifer is a topographically closed basin that is either partially drained if a component of its ground water discharge reaches Indian Hot Springs or undrained if all its natural ground water discharge is to Laguna El Cuervo. PMID:16149972

Hibbs, Barry J; Darling, Bruce K

48

Hydraulic processes on alluvial fans  

SciTech Connect

Alluvial fans are among the most prominent landscape features in the American Southwest and throughout the semi-arid and arid regions of the world. The importance of developing a qualitative and quantitative understanding of the hydraulic processes which formed, and which continue to modify, these features derives from their rapid and significant development over the past four decades. As unplanned urban sprawl moved from valley floors onto alluvial fans, the serious damage incurred from infrequent flow events has dramatically increased. This book presents a discussion of our current and rapidly expanding knowledge of hydraulic processes on alluvial fans. It addresses the subject from a multidisciplinary viewpoint, acquainting the reader with geological principles pertinent to the analysis of hydraulic processes on alluvial fans.

French, R.H.

1987-01-01

49

Alluvial fan susceptibility to thermoerosion in a small arctic basin,Pangnirtung, NU  

NASA Astrophysics Data System (ADS)

An exceptional rainstorm, high air temperature, thick snow cover and low soil permeability due to high permafrost table in early summer are some of the main causes that led to an extreme peak discharge of the Duval River, in Pangnirtung, Nunavut, on June 8, 2008. The 95 km2 catchment is located on mountainous terrain and the river flows in a steep channel down to a large Holocene alluvial fan on which the community is partially built. In a matter of several hours, an estimated volume of 91 000 m3 of sediments were eroded by the combined mechanical and thermal action of flowing water (thermoerosion). The bouldery main channel of the river was overdeepened by nearly 10 m while the permafrost river banks were undercut up to ~ 80 m laterally. The weight of the undercut bank eventually exceeded the strength of the permafrost and they collapsed, permanently damaging two bridges. As the Duval River flows through the community, the damage to the bridges resulted in limited access to some vital services such as distribution of drinking water and sewage transport. This event shows how climate change and, more specifically, the potential increase in the recurrence of extreme climatic events can trigger landscape hazards, raising safety concerns and infrastructure issues in northern communities. In order to help develop a more resilient community, this study focuses on understanding the process of thermal erosion and on assessing the potential risk of reoccurrence of a high magnitude fluvial event in Pangnirtung. The susceptibility to thermoerosion of the alluvial fan on which the river flows was determined by measuring the main characteristics of the permafrost (grain size, temperature profile, water and ice content) and of the Duval River (water temperature, discharge, channel slope). The unconsolidated sediments (silty-sand matrix till), the low ice-content and the relatively high permafrost temperature at the 12 m depth (-2.8 °C) are all factors promoting thermal erosion. However, the bouldery pavement of the river bed and at the foot of the river banks limits contact between water and permafrost and therefore inhibits heat transfer. The size of the boulders (over a meter in diameter) indicates that a particularly strong discharge is necessary to move them in order to expose permafrost to water. As the river is not gauged and precipitation data are sparse, estimates of the flow regime at the time of the thermal erosion event were derived from the assessment of the convective heat transport coefficient based on the size and rate of cutting of the thermal erosion notch as observed and photographed by community members.

Gosselin, P.; Allard, M.; Falardeau-Marcoux, C.

2011-12-01

50

Potential incremental seepage losses in an alluvial channel in the Rio Grande Basin, New Mexico  

USGS Publications Warehouse

A two-dimensional, digital, cross-sectional model was used to simulate seepage of water from an alluvial channel, which had the general characteristic of the Rio Grande channel, into the underlying alluvium within the reach from Cochiti Dam to Elephant Butte Reservoir. Seepage rates were determined for losing and gaining reaches, and reaches affected by pumping of ground water. The seepage rates were computed for stream surcharges (height of additional water applied on top of base flow) ranging from 0.5 foot to 3 feet and for application periods ranging from 1 to 100 days. The net seepage rates, which were nearly identical for each type of reach, ranged from 0.0 cubic foot per second per mile of channel length for a 0.5 foot surcharge applied for 1 day to 0.37 cubic foot per second per mile of channel length for a 3 feet surcharge applied for 100 days, followed by a 180 day seepage return flow from the aquifer. (USGS)

Gold, R. L.

1985-01-01

51

Ground water in the alluvial deposits of Cottonwood Creek Basin, Oklahoma  

USGS Publications Warehouse

Cottonwood Creek basin is a 377 square mile area in central Oklahoma. The rim of the basin has altitudes as high as 1,300 feet, and the mouth is at an altitude of 910. Deposits of Quaternary age consist of alluvium along the stream courses and high terrace deposits along the southern rim of the basin. The alluvium contains a high percentage of clay and silt, ranges in thickness from a few inches to 40 feet, and underlies about 36 square miles of the basin. Sandstone, siltstone, and shale of Permian age, which form the bedrock, consist of the Garber sandstone along the eastern edge, the Hennessey shale through the central part, and Flowerpot shale along the western edge. Replenishment of water in the alluvium is from precipitation, lateral seepage and runoff from adjoining areas, and infiltration from the stream channels during high flows. The major use of ground water in the alluvium is transpiration by cottonwood and willow trees. Virtually no water is withdrawn from the alluvium by wells. (available as photostat copy only)

Stacy, B. L.

1960-01-01

52

Sustainability of Water Resources in Arid Ecosystems: A View from Hei River Basin, China (Invited)  

NASA Astrophysics Data System (ADS)

The northwest of China is characterized by an arid climate and fragile ecosystems. With irrigated agriculture, the region is a prolific producer of cotton, wheat, and maize with some of the highest output per acre in the country. The region is also rich in ore deposits, with the reserves of numerous minerals ranked at or near the top in the country. However, the sustainability of irrigated agriculture and economic development in the region is threaten by severe eco-environmental problems resulting from both global changes and human activities, such as desertification, salinization, groundwater depletion, and dust storms. All these problems are a direct consequence of water scarcity. As global warming accelerates and rapid economic growth continues, the water shortage crisis is expected to worsen. To improve the bleak outlook for the health of ecosystem and environment in northwest China, the Chinese government has invested heavily in ecosystem restoration and watershed management in recent years. However, the effectiveness of such measures and actions depends on scientific understanding of the complex interplays among ecological, hydrological and socioeconomic factors. This presentation is intended to provide an overview of a major new research initiative supported by the National Natural Science Foundation of China to study the integration of ecological principles, hydrological processes and socioeconomic considerations toward more sustainable exploitation of surface water and groundwater resources in the Hei River Basin in northwest China. The Hei River Basin is an inland watershed located at the center of the arid region in East Asia, stretching from Qilianshan Mountains in the south to the desert in the north bordering China’s Inner Mongolia Autonomous Region and Mongolia. The total area of Hei River Basin is approximately 130,000 km2. The research initiative builds on existing research infrastructure and ecohydrological data and seeks to reveal complex interactions and feedbacks between ecosystem functioning and water resources in an arid inland watershed. The findings will provide scientific basis for sustainable water resource management that maximizes the economic benefits without irreparably damaging the ecosystem.

Zheng, C.; Cheng, G.; Xiao, H.; Ma, R.

2009-12-01

53

Monitoring and modeling of two alluvial aquifers in lower Nestos river basin, Northern Greece.  

PubMed

A groundwater monitoring and modeling program in two aquifers within the lower Nestos river basin in Northern Greece is presented. A monitoring network of 54 wells was developed in the two study areas, and groundwater level measurements and water quality sample analyses were conducted for a period of 2.5 years, from March 2007 to October 2009. The field data were used for the calibration and verification of the mathematical model MODFLOW in the two aquifers. The validated model was used to examine ten alternative management scenarios regarding groundwater abstraction in the two aquifers. The study showed that MODFLOW, if properly validated, is a useful and flexible tool in groundwater resources management. PMID:22755533

Boskidis, Ioannis; Pisinaras, Vassilios; Petalas, Christos; Tsihrintzis, Vassilios A

2012-01-01

54

Stratigraphic architecture of alluvial–aeolian systems developed on active karst terrains: An Early Pleistocene example from the Ebro Basin (NE Spain)  

NASA Astrophysics Data System (ADS)

During the Early Pleistocene, fluvial, alluvial and aeolian depositional systems interacted in the central Ebro Basin, Spain, constructing wide alluvial plains over a Neogene evaporite substratum. Fluvial sediments, mainly longitudinal gravel bars and channels, are interdigitated with gravel mass flow and distal mudflat deposits. Aeolian sedimentation is registered as aeolian dunes and sand sheets. Episodes of fluvial deposition alternated with periods of alluvial fan progradation and aeolian deposition. These changes are related to climate-driven water availability. Stratigraphic units and deformation structures show synsedimentary karstification of the evaporite substratum that, although karst was not restricted to any particular climate scenario, was probably favoured during periods of high water availability. Karstification conditioned the development of local sedimentary depocentres which, in turn, influenced the distribution of sedimentary subenvironments as well as the accumulation and preservation of aeolian dunes and lacustrine–palustrine deposits. Stratigraphic architecture shows that thickening of the series due to karst subsidence did not occur homogeneously, but was controlled by diachronous subsidence resulting in numerous angular unconformities. In subsiding karst areas transport capacity was reduced and sediment preservation increased.

Gil, H.; Luzón, A.; Soriano, M. A.; Casado, I.; Pérez, A.; Yuste, A.; Pueyo, E.; Pocoví, A.

2013-10-01

55

Facies architecture and depositional evolution of alluvial fan to fan-delta complexes in the tectonically active Miocene Köprüçay Basin, Isparta Angle, Turkey  

NASA Astrophysics Data System (ADS)

This paper provides the first general account of the facies associations that fill a Miocene fault bounded basin located in the central part of the Isparta Angle (Turkey), in order to define process-controlled sedimentary units reflecting environmental changes in a general tectonic and stratigraphic framework. The northern and western parts of the Köprüçay Basin are occupied by extensive conglomeratic successions belonging to three distinct alluvial fan fan delta systems (AFD), which pass laterally into pelagic mudstones in the deeper part of the basin. In spite of syn- and post-sedimentary tectonics, most of the sedimentary units still display their original relationships. This allows definition and interpretation of the conspicuous facies changes in the clastic successions according to their position along complete sections across the basin. The bulk of the paper is thus devoted to the description of 11 sub-facies types that have been identified in the three AFDs, and their environmental interpretation. As a result, the origin and sedimentary infill of the Köprüçay Basin appears primarily controlled from Langhian to Tortonian by the N S trending Kirkkavak Fault. After uplift and erosion of the western part of the basin, the final closure of the Isparta Angle resulted in a westward displacement of the Anatolian block during Upper Tortonian.

Deynoux, Max; Çiner, Attila; Monod, Olivier; Karab?y?koglu, Mustafa; Manatschal, Gianretto; Tuzcu, Sevim

2005-01-01

56

Geohydrology, water quality, and preliminary simulations of ground-water flow of the alluvial aquifer in the Upper Black Squirrel Creek basin, El Paso County, Colorado  

USGS Publications Warehouse

The upper Black Squirrel Creek basin in eastern El Paso County, Colorado, is underlain by an alluvial aquifer and four bedrock aquifers. Groundwater pumpage from the alluvial aquifer has increased since the mid-1950's, and water level declines have been substantial; the bedrock aquifers virtually are undeveloped. Groundwater pumpage for domestic, stock, agricultural, and municipal uses have exceeded recharge for the past 25 years. The present extent of the effect of pumpage on the alluvial aquifer was evaluated, and a groundwater flow model was used to simulate the future effect of continued pumpage on the aquifer. Measured water level declines from 1974 through 1984 were as much as 30 ft in an area north of Ellicott, Colorado. On the basis of the simulations, water level declines from October 1984 to April 1999 north of Ellicott might be as much as 20 to 30 ft and as much as 1 to 10 ft in most of the aquifer. The groundwater flow models provided a means of evaluating the importance of groundwater evapotranspiration at various stages of aquifer development. Simulated groundwater evapotranspiration was about 43% of the outflow from the aquifer during predevelopment stages but was less than 3% of the outflow from the aquifer during late-development stages. Analyses of 36 groundwater samples collected during 1984 indicated that concentrations of dissolved nitrite plus nitrate as nitrogen generally were large. Samples from 5 of the 36 wells had concentrations of dissolved nitrite plus nitrate as nitrogen that exceeded drinking water standards. Water from the alluvial aquifer generally is of suitable quality for most uses. (USGS)

Buckles, D. R.; Watts, K. R.

1988-01-01

57

The content of chemical elements in alluvial soils and bottom sediments of the Urkan River (the Amur River basin)  

NASA Astrophysics Data System (ADS)

The distribution patterns of the chemical elements in the bottom sediments and alluvial soils of the Urkan River valley (one of the largest tributaries of the Zeya River, a tributary of the Amur River) have been examined. It is shown that the concentrations of the chemical elements in the bottom sediments generally correspond to those in the bedrocks composing the river catchment and in the upper part of the continental earth's crust, though the accumulation of most of the elements in the bottom sediments is somewhat lower. The composition of the microelements in the alluvial soils is mainly determined by the composition of the microelements in the bottom sediments. The alluvial soils are somewhat enriched in Mn, Zn, Co, and Cu, which is related to the biological accumulation of these elements entering the trophic chains.

Sorokina, O. A.; Zarubina, N. V.

2013-06-01

58

Interaction of water components in the semi-arid Huasco and Limarí river basins, North Central Chile  

Microsoft Academic Search

For sustainable water resource management in semi-arid regions, sound information is required about interactions between the different components of the water system: rain\\/snow precipitation, surface\\/subsurface run-off, groundwater recharge. Exemplarily, the Huasco and Limarí river basins as water stressed river catchments have been studied by isotope and hydrochemical methods for (i) the origin of water, (ii) water quality, (iii) relations of

G. Strauch; R. Oyarzún; F. Reinstorf; J. Oyarzún; M. Schirmer; K. Knöller

2009-01-01

59

Simulated Ground-Water Flow in the Hueco Bolson, an Alluvial-Basin Aquifer System Near El Paso, Texas.  

National Technical Information Service (NTIS)

The neighboring cities of El Paso, Texas, and Ciudad Juarez, Chihuahua, Mexico, have historically relied on ground-water withdrawals from the Hueco Bolson, an alluvial-aquifer system, to supply water to their growing populations. By 1996, ground-water dra...

C. E. Heywood R. M. Yager

2003-01-01

60

The Italian Project S2 - Task 4:Near-fault earthquake ground motion simulation in the Sulmona alluvial basin  

NASA Astrophysics Data System (ADS)

Recently the Italian Department of Civil Protection (DPC), in cooperation with Istituto Nazionale di Geofisica e Vulcanologia (INGV) has promoted the 'S2' research project (http://nuovoprogettoesse2.stru.polimi.it/) aimed at the design, testing and application of an open-source code for seismic hazard assessment (SHA). The tool envisaged will likely differ in several important respects from an existing international initiative (Open SHA, Field et al., 2003). In particular, while "the OpenSHA collaboration model envisions scientists developing their own attenuation relationships and earthquake rupture forecasts, which they will deploy and maintain in their own systems", the main purpose of S2 project is to provide a flexible computational tool for SHA, primarily suited for the needs of DPC, which not necessarily are scientific needs. Within S2, a crucial issue is to make alternative approaches available to quantify the ground motion, with emphasis on the near field region. The SHA architecture envisaged will allow for the use of ground motion descriptions other than those yielded by empirical attenuation equations, for instance user generated motions provided by deterministic source and wave propagation simulations. In this contribution, after a brief presentation of Project S2, we intend to illustrate some preliminary 3D scenario simulations performed in the alluvial basin of Sulmona (Central Italy), as an example of the type of descriptions that can be handled in the future SHA architecture. In detail, we selected some seismogenic sources (from the DISS database), believed to be responsible for a number of destructive historical earthquakes, and derive from them a family of simplified geometrical and mechanical source models spanning across a reasonable range of parameters, so that the extent of the main uncertainties can be covered. Then, purely deterministic (for frequencies < 2Hz) and hybrid deterministic- stochastic source and propagation simulations are carried out for different fault rupture scenarios (but including important features such as the dominant near-surface geology), and the results in terms of representative ground motion parameters appropriately enveloped. The fully 3D problem is solved using the Spectral Element (SE) method, extensively published by Faccioli and his co-workers, and Quarteroni and co- workers, starting from 1996, and the computational code GeoELSE (Stupazzini et al., 2009; http://GeoELSE.stru.polimi.it/). Finally, numerical results are compared with available data and attenuation relationships of peak values of ground motion in the near-fault regions elsewhere. Based on the results of this work, the unfavorable interaction between fault rupture, radiation mechanism and complex geological conditions may give rise to large values of peak ground velocity (exceeding 1 m/s) even in low-to-moderate seismicity areas, and therefore increase considerably the level of seismic risk, especially in highly populated and industrially active regions, such as the Central Italy. Faccioli E., Maggio F., Paolucci R. and Quarteroni A. (1997),2D and 3D elastic wave propagation by a pseudo-spectral domain decomposition method, Journal of Seismology, 1, 237-251. Field, E.H., T.H. Jordan, and C.A. Cornell (2003), OpenSHA: A Developing Community-Modeling Environment for Seismic Hazard Analysis, Seism. Res. Lett. 74, 406-419. Stupazzini M., R. Paolucci, H. Igel (2009), Near-fault earthquake ground motion simulation in the Grenoble Valley by a high-performance spectral element code, accepted for publication in Bull. of the Seism. Soc. of America.

Stupazzini, M.; Smerzini, C.; Cauzzi, C.; Faccioli, E.; Galadini, F.; Gori, S.

2009-04-01

61

Well-log signatures of alluvial-lacustrine reservoirs and source rocks, Lagoa-Feia Formations, Lower Cretaceous, Campos Basin, offshore Brazil  

SciTech Connect

The Campos basin is situated in offshore southeastern Brazil. The Lagoa Feia is the basal formation in the stratigraphic sequence of the basin, and was deposited during rifting in an evolving complex of lakes of different sizes and chemical characteristics, overlying and closely associated with rift volcanism. The stratigraphic sequence is dominated by lacustrine limestones and shales (some of them organic-rich), and volcaniclastic conglomerates deposited on alluvial fans. The sequence is capped by marine evaporites. In the Lagoa Feia Formation, complex lithologies make reservoirs and source rocks unsuitable for conventional well-log interpretation. To solve this problem, cores were studied and the observed characteristics related to log responses. The results have been extended through the entire basin for other wells where those facies were not cored. The reservoir facies in the Lagoa Feia Formation are restricted to levels of pure pelecypod shells (''coquinas''). Resistivity, sonic, neutron, density, and gamma-ray logs were used in this work to show how petrophysical properties are derived for the unconventional reservoirs existing in this formation. The same suite of logs was used to develop methods to define geochemical characteristics where source rock data are sparse in the organic-rich lacustrine shales of the Lagoa Feia Formation. These shales are the main source rocks for all the oil discovered to date in the Campos basin.

Abrahao, D.; Warme, J.E.

1988-01-01

62

Geophysical and hydrogeologic investigations of two primary alluvial aquifers embedded in the southern San Andreas fault system: San Bernardino basin and upper Coachella Valley  

NASA Astrophysics Data System (ADS)

This study of alluvial aquifer basins in southern California is centered on observations of differential surface displacement and the search for the mechanisms of deformation. The San Bernardino basin and the Upper Coachella Valley aquifers are bound by range fronts and fault segments of the southern San Andreas fault system. I have worked to quantify long-term compaction in these groundwater dependent population centers with a unique synthesis of data and methodologies using Interferometric Synthetic Aperture Radar (InSAR) and groundwater data. My dissertation contributes to the understanding of alluvial aquifer heterogeneity and partitioning. I model hydrogeologic and tectonic interpretations of deformation where decades of overdraft conditions and ongoing aquifer development contribute to extreme rapid subsidence. I develop the Hydrogeologic InSAR Integration (HII) method for the characterization of surface deformation in aquifer basins. The method allows for the separation of superimposed hydraulic and/or tectonic processes in operation. This formalization of InSAR and groundwater level integration provides opportunities for application in other aquifer basins where overdraft conditions may be causing permanent loss of aquifer storage capacity through compaction. Sixteen years of SAR data for the Upper Coachella Valley exhibit rapid vertical surface displacement (? 48mm/a) in sharply bound areas of the western basin margin. Using well driller logs, I categorize a generalized facies analysis of the western basin margin, describing heterogeneity of the aquifer. This allowed for assessment of the relationships between observed surface deformation and sub-surface material properties. Providing the setting and context for the hydrogeologic evolution of California's primary aquifers, the mature San Andreas transform fault is studied extensively by a broad range of geoscientists. I present a compilation of observations of creep, line integrals across the Pacific-North America Plate Boundary, and strain tensor volumes for comparison to the Working Group 2007 (UCERF 2) seismicity-based deformation model. I find that the moment accumulation across the plate boundary is consistent with the deformation model, suggesting fault displacement observations within the plate boundary zone accurately capture the strain across the plate boundary. This dissertation includes co-authored materials previously published, and also includes unpublished work currently under revisions for submission to a technical journal.

Wisely, Beth Ann

63

Land use indicators of a watershed in arid region, western Rajasthan using Remote Sensing and GIS  

Microsoft Academic Search

The vegetation dynamics and land use\\/land cover types of Birantiya Kalan watershed located in the arid tracts of western Rajasthan\\u000a have been characterized and evaluated using Remote Sensing and Geographical Information System (GIS). The watershed under\\u000a study falls in the transitional plain of Luni Basin and is characterized by Aravali ranges in the eastern half and vast alluvial\\u000a plains in

Debashis Chakraborty; Dibyendu Dutta; H Chandrasekharan

2001-01-01

64

The organic and mineral matter contents in deposits infilling floodplain basins: Holocene alluviation record from the K?odnica and Osob?oga river valleys, southern Poland  

NASA Astrophysics Data System (ADS)

The work examines the timing and environmental conditions of floodplain sedimentation in the valleys of the upland K?odnica and piedmont Osob?oga rivers in the Upper Odra River basin. A distribution of 52 14C-ages shows relatively high floodplain sedimentation at the Late Glacial-Holocene transition, more stable floodplain environments since the Early (in the K?odnica Valley) and Middle Holocene (in the Osob?oga Valley) and a gradual increase in floodplain deposition in the Late Holocene (since < 3.4 kyr BP). Organic matter [OM] and mineral matter [MM] fluctuations were correlated with variables responsible for the activation of erosion (i.e. vegetation changes, human impact and hydrological events) as well as factors affecting the local record of sedimentation (i.e. valley morphology, hydrologic conditions and episodes of local erosion). A clear relationship is shown between an increase in alluviation and climate- or human-induced extension of unforested areas. The deposition of mineral-rich sediments increases rapidly during periods characterized by non-arboreal pollen values exceeding approximately 8% in pollen diagrams. On the other hand, the results obtained do not confirm significant interactions between Holocene changes in forest composition and alluviation. Despite the settlement of agrarian groups, the sedimentary record of human activity in the Osob?oga catchment is very poor during the Neolithic and early Bronze Age. A large-scale alluviation of the Osob?oga and K?odnica valleys was initiated during the settlement of people of the Lusatian culture from the middle Bronze Age and escalated in the early Middle Ages and Modern Times. The deposition of products of soil erosion was limited to between ca. 1.9-1.2 kyr BP, probably due to demographic regression during the Migration Period. Comparison of OM/MM fluctuations with phases of increased fluvial activity does not show a relationship between Holocene wetter phases and catchment sediment yield. Sedimentary episodes in the Upper Odra basin also show a low degree of correlation with the probability density curve of the 14C-ages. The results obtained in the K?odnica and Osob?oga valleys indicate a strong to moderate correlation between the spatial distribution of the study sites and the origin of MM-rich deposits, but a weak correlation between the spatial distribution of the study sites and TOC content. Such a pattern suggests that OM/MM fluctuations relate predominantly to the changes in sediment yield, although morphological conditions have a significant impact on the capture potential of sedimentary basins during phases of alluviation. Additionally, high OM content is not a simple function of an increase in wetness of the sedimentary environment. On the other hand, hydrologically-conditioned hiatuses as well as erosion episodes impoverish the sedimentary record, complicating the consideration on the geochronology of deposits and making it difficult to calculate reliable accumulation rates. However, they do not reduce the value of OM/MM fluctuations as an indicator of alluviation events for a preserved series of sediments.

Wójcicki, K. J.; Marynowski, L.

2012-07-01

65

GIS analysis of depositional slope change at alluvial-fan toes in Japan and the American Southwest  

Microsoft Academic Search

Slope change at alluvial-fan toes provides a clue to understanding differences between alluvial fans and other depositional landforms. This paper analyses topographic data for 430 alluvial fans and their adjacent lowlands in Japan and the American Southwest (ASW), typical humid and arid regions with abundant alluvial fans. Arcs showing fan toes were identified and representative areas above and below each

Akiko Hashimoto; Takashi Oguchi; Yuichi Hayakawa; Zhou Lin; Kyoji Saito; Thad A. Wasklewicz

2008-01-01

66

Water Availability and Use Pilot: Methods Development for a Regional Assessment of Groundwater Availability, Southwest Alluvial Basins, Arizona.  

National Technical Information Service (NTIS)

Arizona is located in an arid to semiarid region in the southwestern United States and is one of the fastest growing States in the country. Population in Arizona surpassed 6.5 million people in 2008, an increase of 140 percent since 1980 (U.S. Census Bure...

B. E. Thomas F. D. Tillman J. B. Callegary J. T. Cordova S. A. Leake

2011-01-01

67

Stable Water Isotope Tracing and Model Evaluation in Large Basins: the `` Special Case'' of Semi-Arid Catchments  

NASA Astrophysics Data System (ADS)

The use of stable water isotopes in hydro-climate monitoring and modelling offers a new means of measuring and parameterizing critical processes. Here we review these specifically for the case of semi-arid basins where water resources are essential for potable supply and agriculture around the world. The verity and performance of existing models is examined using observations and simulations of stable water isotopes in rivers, aquifers and their precedent precipitations. Here we report on the Murray-Darling basin in Australia as one example of the `` special case'' of semi-arid catchments and use these data and results to examine evaluation and refinement of models and predictions on three time-scales: (i) minutes to months, (ii) years to decades and (iii) tens to thousands of years. We find that modelled isotopic depletions become increasingly sensitive to parameterized characteristics as the time period is decreased and/or a significant atmospheric circulation disturbance occurs. Minute to monthly isotope fluxes simulated by land surface schemes and river hydrology models allow comparison of the partition of precipitation between transpiration, run-off and open-water evaporation with isotope observations from 2002 and 2003. A range of atmospheric global circulation models (GCMs) simulations of key hydrological parameters over years to decades reveals poor results for the majority (13 in 20). We show that between 1979 and 1996 modelled groundwater is apparently being `tapped' in many of these GCMs at rates required to allow evaporation to greatly exceed precipitation (Ev>>Pr). Analysis of the `` good"'' versus the `` poor'' hydro-climate models reveals that unwitting application of `` poor'' models to current and future hydrological issues in semi-arid basins generates errors of over 100% in predictions. Isotopes demonstrate that in warm semi-arid regions, in contrast to the behaviour in cool temperate zones, groundwater recharge occurs only when rainfall intensities exceed a threshold suggesting a need to, and a method of, improving aquifer replenishment prediction of tens to thousands of years. Overall, these isotopic results clearly offer novel additions to the traditional tools used in evaluating and improving hydro-climate models and their sub- and super- components. The greatest benefits seem likely to be delivered in semi-arid catchments where subtle isotope tracing and measurement should be combined urgently with gross water flux monitoring to enhance simulation and management schemes.

Henderson-Sellers, A.; Airey, P.; McGuffie, K.; Bradd, J.; Stone, D.

2004-05-01

68

Lower Eocene alluvial paleosols (Willwood Formation, Northwest Wyoming, U.S.A.) and their significance for paleoecology, paleoclimatology, and basin analysis  

USGS Publications Warehouse

The lower Eocene Willwood Formation of northwest Wyoming is a 700 m thick accumulation of alluvial floodplain and channel mudstones and sandstones, nearly all of which show paleopedogenic modifications. Pedogenesis of Willwood sandstones is indicated by taproot and vertebrate and invertebrate bioturbation, early local cementation by calcium carbonate, and thin illuviation cutans on clastic grains. Pedogenesis in Willwood mudstones is indicated by plant bioturbation, insect and other invertebrate burrow casts and lebensspuren; free iron, aluminum, and manganese mobilization, including hydromorphic gleying; sesquioxide and calcareous glaebule formation in lower parts of the solum; presence of clay-rich and organic carbon-rich zones; and well differentiated epipedons and albic and spodic horizons. Probable A horizons are also locally well developed. Occurrence of variegated paleosol units in thick floodplain mudstone deposits and their association with thin, lenticular, and unconnected fluvial sandstones in the Willwood Formation of the central and southeast Bighorn Basin suggest that these soils formed during times of rapid sediment accumulation. The tabular geometry and lateral persistence of soil units as well as the absence of catenization indicate that Willwood floodplains were broad and essentially featureless. All Willwood paleosols were developed on alluvial parent materials and are complex in that B horizons of younger paleosols were commonly superimposed upon and mask properties of suspected A and B horizons of the next older paleosols. The soils appear to be wet varieties of the Spodosol and Entisol groups (aquods and ferrods, and aquents, respectively), though thick, superposed and less mottled red, purple, and yellow paleosols resemble some ultisols. Most Willwood paleosols resemble warm temperate to subtropical alluvial soils that form today under alternating wet and dry conditions and (or) fluctuating water tables. The up-section decrease in frequency of gley mottles, increase in numerical proportion and thickness of red versus orange coloration, and increase in abundance of calcrete glaebules indicate better drained soils and probably drier climate in late Willwood time. This drying is believed to be related to creation of rain shadows and spacing of rainfall (but not necessarily decrease in absolute rainfall) due to progressive tectonic structural elevation of the mountainous margins of the Bighorn Basin. ?? 1981.

Bown, T. M.; Kraus, M. J.

1981-01-01

69

Issues associated with the distinction between climatic and tectonic controls on Permian alluvial fan deposits from the Kotzen and Barnim Basins (North German Basin)  

Microsoft Academic Search

Facies analysis focussing on coarse-grained sediments has been carried out on more than 2500m of drill cores from seven wells from southern margins of the North German Basin (NGB). The NGB forms a central element of the Southern Permian Basin (SPB). The wells exposed conglomerates and sandstones of the Rotliegend Grüneberg and Parchim Formations deposited in the Kotzen Basin and

Enrico Kallmeier; Christoph Breitkreuz; Hubert Kiersnowski; Marion Geißler

2010-01-01

70

Volcaniclastic-alluvial sedimentation interaction in the Tordillo Fm., Upper Jurassic, Neuquén Basin (Argentina): An approach for paleogeographic and tectonic development.  

NASA Astrophysics Data System (ADS)

The Neuquén Basin is a Mesozoic back-arc basin located in central-western Argentina and eastern Chile and today incorporated into the Andean retro-arc foreland basin. The Upper Jurassic Tordillo Formation at the northern Neuquén Basin, Argentina, was developed during a generalized subsidence with still clear fault influence that followed a Late Triassic-Early Jurassic rifting phase. Although this formation comprises a multi-stage suit of predominantely alluvial sediments that is heterolithic in nature, aeolian and volcaniclastic sediments are also present. Volcaniclastic sediments are mainly andesitic in composition where subaerial pyroclastic flows and fallout deposits (and their remobilised sediments) are common. They are interbedded with fluvial braided and meandering sediments showing a clear interdependence. Sediment supply in the Neuquén Basin was markedly influenced by the uplift and later subsidence controlled by the magmatic activity. Explosive volcanic eruptions coupled with sporadic high rainfall events led to transportation and accumulation of large quantities of coarse volcaniclastic debris, including dm-scale blocks. Defined volcaniclastic facies include pyroclastic and epiclastic deposits of both primary and secondary origin. Pyroclastic deposits include flow and fall deposits, this latter with bombs and lapilli deposits. They are massive or show sequences. These latter normally show erosive base and are represented by 0.4 to 0.8m in thickness of reverse, normal and normal-reverse grading in which traction structures as lamination and cross-bedding appear. Associated flame, load and scour structures are also common at the top of the sequences. All of these deposits are related to a range that varies from subaerial to shallow water in origin. Some of those of shallow water may have resulted from the accumulation of decelerating turbulent suspensions of low density currents. Available detailed information from the evolution of the Neuquén Basin during the episodes without marine deposition is still scarce, particularly for the late Jurassic. This determines great limitations for reconstructing that evolution within a paleogeographic, magmatic and tectonic context. This study gives some clues for a better understanding of these aspects.

López-Gómez, José; Martín-Chivelet, Javier; Lago, Marceliano; Palma, Ricardo; Kietzmann, Diego

2010-05-01

71

Development and Application of Grid-GA Model in a Semi-Humid and Semi-Arid Basin  

NASA Astrophysics Data System (ADS)

Modeling the hydrologic processes in semi-arid and semi-humid basins is specially challenging due to the specific characteristics of these basins. In this paper, combining with GIS technology and DEM, the Grid- and Green-Ampt infiltration approach-based distributed hydrologic model of the runoff-production in excess infiltration is developed (Grid-GA model). In Grid-GA model, the Green-Ampt infiltration approach has improved in three parts: (1) the effective hydraulic conductivity of the wetting front at saturation, is power function decaying with the depth of the wetting front; (2) F, the cumulative infiltration, is modified at the end of every time step; (3) the moisture content rate of the soil, is redistribution during the infiltration process. In flow concentration formation, there are kinematic wave approach for un-channel grid and Muskingum approach for channel grid. The model described that includes vegetation and root interception, evapotranspiration, and runoff generation via the excess infiltration mechanism, as well as subsurface via the Darcian approach used by TOPMODEL, runoff concentration, and flow routing. The water exchange among grids within the watershed and the runoff routing along the river drainage networks are taken into consideration in the model. The Grid-GA model is applied to Gaoli basin in Yi River, a tributary of the Yishusi Watershed, with an area of 552 km2 for flood simulation. The results show that the model performs well in the simulation and can be used for flood forecasting in the semi-humid and semi-arid region.

Wang, L.; Li, Z.; Bao, H.; Yu, Z.

2009-12-01

72

History and Variability of aridity in the Tarim Basin since Late Miocene and its links to Tibetan Growth and global ice-volume change  

NASA Astrophysics Data System (ADS)

Modern climate environmental system in China is composed of monsoon region in the south-east where the annual precipitation is more than 400mm,, arid region in the north-west where the annual precipitation is less than 200mm, and the transitional zone between them. Results of numerical simulation show that the monsoon-arid environmental system of China has been influenced greatly by the growth of the Tibetan Plateau since Miocene (An et al., 2006). Numerous climate information, including the precipitation and temperature changes, has been obtained in the eastern monsoon-effected region, but that are very scarce in the western arid region. As the classical representative of the arid region, the Tarim Basin is very important to understand the coupling mechanisms among Tibet uplift, monsoon-arid environmental evolution, and global climate change. Lop Nor is located in the east part of the Tarim Basin, an ideal location to monitor drying of Asian inland. In year 2004, the LS2 core (39°46.65'N, 88°23.3'E, 1050.60m long) in the Lop Village was retrieved under the support of the project of Continental Environmental Scientific Drilling of China. Magnetostratigraphic result indicates that the age of the bottom of LS2 core is around 7.2Ma. Multiple proxies such as magnetic susceptibility, grain size, total organic carbon, total nitrogen, ?13Corg, and carbonate content as well as ?13C and ?18O of carbonate were generated to reconstruct the history and variability of aridity in the Tarim basin since 7.2Ma. The results reveal a remarkable drying in the Tarim basin around 5.5-5.3 Ma, possibly related to the growth of the Tibetan Plateau. Significant humid-dry variability under gradual drying trend is closely linked to global ice- volume change represented by marine ?18O records during the Plio-Pleistocene.

Chang, H.; Liu, W.; An, Z.; Sun, Y.; Song, C.; Wang, N.; Song, Y.; Fu, C.

2008-12-01

73

Dry Weather Water Quality Loadings in Arid, Urban Watersheds of the Los Angeles Basin, California, USA  

Microsoft Academic Search

Dry weather runoff in arid, urban watersheds may consist entirely of treated wastewater effluent and ?or urban nonpoint source runoff, which can be a source of bacteria, nutrients, and metals to receiving waters. Most studies of urban runoff focus on stormwater, and few have evaluated the relative contribution and sources of dry weather pollutant loading for a range of constituents

Eric D. Stein; Drew Ackerman

2007-01-01

74

Rainfall–interception–evaporation–runoff relationships in a semi-arid catchment, northern Limpopo basin, Zimbabwe  

Microsoft Academic Search

Characterizing the response of a catchment to rainfall, in terms of the production of runoff vs the interception, transpiration and evaporation of water, is the first important step in understanding water resource availability in a catchment. This is particularly important in small semi-arid catchments, where a few intense rainfall events may generate much of the season's runoff. The ephemeral Zhulube

David Love; Stefan Uhlenbrook; Gerald Corzo-Perez; Steve Twomlow; Pieter van der Zaag

2010-01-01

75

Sensitivity of a semi-arid tropical lake basin to environmental changes (Lake Ihotry basin, South-West of Madagascar)  

Microsoft Academic Search

The objective of the study is to analyse the sensitivity of water ressources in a large semi-arid catchment, based on few hydro-meteorological and satellite images analysis. The site is located in the south-west of Madagascar. The catchment, which surface is 3000 km^2, is limited in its eastern side by a North-south relief up to 1000m high. The most important part

C. Vallet-Coulomb; A. Maurin; F. Gasse; L. Ferry; L. Robison

2003-01-01

76

Isotopes and groundwater management strategies under semi-arid area: case of the Souss upstream basin (Morocco).  

PubMed

This study concerns the Souss upstream basin. The objective is to investigate the characteristics of surface water and groundwater, to assess the impact of artificial recharge as reinforcement of the natural replenishment and assess the renewal of groundwater under semi-arid area. Two major water types are observed: (i) surface waters and upstream springs (least mineralized) and (ii) all groundwater samples (prevailing calcium and magnesium bicarbonate water type). Water isotopes show a low evaporation of precipitations during infiltration. Impoverishment in heavy isotopes is the characteristic of mountain rainfalls, or of a climate colder and wetter than present. Carbon-14 activities (34-94 pmc) indicate a long residence time. The artificial recharge is low compared to the reservoir volume, due to which the renewal rate is also low. PMID:21377885

Bouragba, L; Mudry, J; Bouchaou, L; Hsissou, Y; Krimissa, M; Tagma, T; Michelot, J L

2011-02-23

77

Redbeds from the Middle Muschelkalk (Middle Triassic) of the SW Germanic Basin: arid environments from Pangea's interior  

NASA Astrophysics Data System (ADS)

The facies of a redbed succession from the lower Middle Muschelkalk of the SW Germanic Basin allows reconstruction of the depositional environment and inference with regard to the climate in a little studied part of Pangea's interior. The redbeds are dominated by fine-grained terrigenous deposits, with both intercalated thin sandstone and carbonate beds. The clastics were derived from the nearby hinterland, and their facies suggest episodic deposition on a playa mud flat or flood plain. The occurrence in the lower part of the succession of sand-patch breccias, ooids, and dolomicrite beds suggests an origin in saline pans and playa lakes. These diverse facies, and phreatic dolomites, reflect an arid climate during deposition.

Vecsei, A.; Mandau, T.

78

Soil water conservation and rainwater harvesting strategies in the semi-arid Mzingwane Catchment, Limpopo Basin, Zimbabwe  

NASA Astrophysics Data System (ADS)

Various soil water management practices have been developed and promoted for the semi arid areas of Zimbabwe. These include a variety of infield crop management practices that range from primary and seconday tillage approaches for crop establishment and weed management through to land forming practices such as tied ridges and land fallowing. Tillage methods evaluated in this study include deep winter ploughing, no till tied ridges, modified tied ridges, clean and mulch ripping, and planting basins. Data collected from the various trials since the 1990s show that mulch ripping and other minimum tillage practices consistently increased soil water content and crop yields compared to traditional spring ploughing. Trial results also showed higher soil loss from conventionally ploughed plots compared to plots under different minimum tillage practices.

Mupangwa, Walter; Love, David; Twomlow, Steve

79

High-resolution sequence stratigraphy of an alluvial fan–fan delta environment: stratigraphic and geodynamic implications – An example from the Keuper Chaunoy Sandstones, Paris Basin  

Microsoft Academic Search

Facies analysis of the Chaunoy Formation, conducted as the first stage of this study, reveals that the corresponding fluvial system essentially involved bedload deposition, 2-D and 3-D megaripple migration, and debris-flow deposition. Such processes are characteristic of alluvial fan depositional environments. These alluvial fan deposits pass laterally eastward into a shallow lacustrine environment. In stage 2 of the study, electrofacies

Sylvie Bourquin; Christophe Rigollet; Philippe Bourges

1998-01-01

80

Hydrologic behavior and flood probability for selected arid basins in Makkah area, western Saudi Arabia  

Microsoft Academic Search

In arid regions, flash floods often occur as a consequence of excessive rainfall. Occasionally causing major loss of property\\u000a and life, floods are large events of relatively short duration. Makkah area in western Saudi Arabia is characterized by high\\u000a rainfall intensity that leads to flash floods. This study quantifies the hydrological characteristics and flood probability\\u000a of some major wadis in

Ali M. Subyani

2011-01-01

81

Late Eocene arid climate in Asia inferred from multi-proxy sclerochronology using oyster shells from the Tarim Basin  

NASA Astrophysics Data System (ADS)

The Asian climate is characterized by a strong duality between monsoon dominant climate in southeastern Asia and arid climate in central Asia. Based on climate modelling, this pattern has been explained by two main driving mechanisms associated to the Indo-Asia collision: uplift of Tibetan Plateau and/or retreat of an epicontinental sea formerly covering Asia. However, climate proxies are lacking to test these hypotheses and understand how and when this climate pattern was established. The aim of this study is to develop a new method to understand the Late Eocene climate in central Asia, when the Paratethys was still covering the continent. A crucial task to this end is to reconstruct the climate seasonality in central Asia: when and how the climate changed from a probably temperate climate, due to the sea presence, to an arid climate? Did this climate change have an impact on the monsoon intensification in southestern Asia? Here we use bivalve sclerochronology to assess the Eocene climate variability on seosonal time scales in Central Asia. Well preserved oyster shells (Sokolowia buhsii, Grewingk) were sampled in marine sediments from Lutetian to Bartonian age in southwestern Tarim Basin, Xinjiang, China (Aertashi and Kezi sections). The Paratethys sea was shallow and partially closed, thus the challenge is to distinguish temperature from salinity effects on the biomineralization. Here, we present a new method using multi-proxy approach. The fossils were cut perpendicularly to the maximum growth axis to expose incremental yearly growth lines of the shell to be analysed. We first obtained Mg/Ca record using LA ICP-MS indicative of the temperature variations. We then recovered an isotopic sclerogeochemistry (?18Oc) record using micromilling extraction to assess the ?18Ow (and thereby the salinity) of the sea. Results show that seasonal temperature variability was considerable. Furthemore salinity increase during summers indicating a negative water balance. Thus, we infer that central Asian climate was already very arid during the Late Eocene, although the Paratethys sea was still covering the Asian continent. This is an apparent contradiction with the first assumption of a temperate climate before sea retreat but is in agreement with coeval palynological data from the Tarim Basin and with recent climate models of Eocene Asian monsoons.

Bougeois, Laurie; de Rafélis, Marc; Reichart, Gert-Jan; de Nooijer, Lennart J.; Nicollin, Florence; Dupont-Nivet, Guillaume

2013-04-01

82

Sahra integrated modeling approach to address water resources management in semi-arid river basins  

Microsoft Academic Search

Water resources decisions in the 21Sf Century that will affect allocation of water for economic and environmental will rely on simulations from integrated models of river basins. These models will not only couple natural systems such as surface and ground waters, but will include economic components that can assist in model assessments of river basins and bring the social dimension

E. P. Springer; Hoshin V. Gupta; David S. Brookshire; Y. Liu

2004-01-01

83

Why conceptual groundwater flow models matter: a trans-boundary example from the arid Great Basin, western USA  

NASA Astrophysics Data System (ADS)

Spring and Snake valleys, western USA, are scheduled for development and groundwater export to Las Vegas, Nevada (USA). New work, compared to published studies, illustrates the critical role of conceptual models to underpin water withdrawals in arid regions. Interbasin flow studies suggest that 30-55 % of recharge to Snake Valley arrives from adjacent Spring Valley. This study, however, suggest little or no interbasin flow; rather, Spring and Snake valleys comprise separate systems. Contrary to expectation, ?D and ?18O contours are perpendicular to proposed interbasin flow paths. 14C age gradients up to 10 ka along interbasin flow paths indicate that old waters are not displaced by such fluxes. 14C and 3H patterns indicate local recharge occurs in adjacent mountain ranges and is transferred to basin-fill by losing streams, mountain front recharge, and upward leakage from carbonate bedrock beneath basins. The choice of conceptual models is critical for groundwater development. Simple analyses of water withdrawals indicate that monitoring discharges at desert springs is an inadequate protective measure. Once flows decline, recovery is lengthy even if pumping is stopped. The conceptual framework behind quantitative evaluations of sustainable yield is critical to determine the ability of a groundwater system to deliver sustained withdrawals.

Gillespie, J.; Nelson, S. T.; Mayo, A. L.; Tingey, D. G.

2012-09-01

84

Northwest Arid Lands : an introduction to the Columbia Basin shrub-steppe  

SciTech Connect

This book explores the rich variety of life in shrub-steppe lands of the Columbia River Basin. It describes, for a non-technical audience, the flora, fauna, and geology of the lower Columbia Basin in and around the Tri-Cities, Washington. Features include color photos and maps of shrub-steppe plants and animals; lists and illustration of common plants, mammals, reptiles, amphibians, birds, fish, and species of conservation concern; tips on places to see wildflowers and wildlife; geological travel logs from the Tri-Cities to Seattle and Spokane; and a comprehensive bibliography and definition of ecological terms.

O'Connor, Georganne P. (BATTELLE (PACIFIC NW LAB)); Wieda, Karen J. (BATTELLE (PACIFIC NW LAB))

2001-04-15

85

A Basin-Averaged Water Balance Approach to Estimate Catchment-Scale Groundwater Flow in a Semi-arid Mountainous Catchment  

NASA Astrophysics Data System (ADS)

Quantification of the contribution of groundwater flow from highland areas of mountainous watersheds to semi-arid and arid valley bottom unconsolidated aquifers is increasingly needed for the assessment of water resources in many populated areas. In mountainous environments, however, data for Darcy equation parameters are limited, leading to uncertainty in estimates of groundwater flow of up to two or more orders of magnitude. An alternative method for estimating regional groundwater flow from highland to valley bottom areas was developed for the semi-arid Okanagan Basin, British Columbia, Canada. The method involved a basin-averaged water balance approach, using mean annual surface water run-off (RO) data for 9 gauged tributaries with spatially distributed estimates of mean annual precipitation (P) and actual evapotranspiration (AET), to develop basin-averaged relationships for prediction of recharge-driven groundwater flow through the bedrock highland areas. Groundwater flow from highland bedrock areas to unconsolidated valley bottom aquifers was subsequently accounted for through a calibration exercise using a spreadsheet tool developed for the project. Average annual AET was the most difficult parameter to quantify at the tributary catchment scale. Spatially distributed AET estimates were developed using temperature and precipitation data, with consideration of expected AET ranges established based on available data for the region. Results for the bedrock areas in the Okanagan Basin indicated basin-averaged partitioning of mean annual precipitation as 68% AET, 19% to surface water run-off (in streams), and 13% to net recharge (groundwater flow). The influence of AET and surface water run-off parameter uncertainty on regional bedrock groundwater flow calculations was a factor of 2 (AET range of 60-70% catchment precipitation) and 1.2 (RO range of 14 to 26%), respectively. This approach allows for preliminary estimates of water budget constrained recharge- driven groundwater flow at the catchment or basin scale.

Neilson-Welch, L. A.; Allard, R.; Geller, D.; Allen, D. M.

2008-12-01

86

Riparian vegetation of two semi-arid Mediterranean rivers: Basin-scale responses of woody and herbaceous plants to environmental gradients  

Microsoft Academic Search

Mediterranean fluvial ecosystems are subjected to ever-increasing water demands and to a wide variety of other human impacts\\u000a with potential negative effects on riparian vegetation. Nevertheless, few studies have compared the importance of human versus\\u000a natural factors in structuring riparian vegetation in this region, particularly in semi-arid areas. We examined basin-scale\\u000a responses of riparian vegetation to the main environmental gradient

M. Jacoba Salinas; J. Jesús Casas

2007-01-01

87

MODELING THE UNIQUE ATTRIBUTES OF ARID ECOSYSTEMS: LESSONS FROM THE JORNADA BASIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Jornada Basin is typical of aridland ecosystems of the southwestern United States and many other regions of the globe: it is water-limited with low annual net primary production (ANPP) and low-standing crop (Szarek 1979; Ludwig 1987). Yet, paradoxically, aridland ecosystems are structurally and ...

88

Geomorphic controls on hydrology and vegetation in an arid basin: Turkana district, northern Kenya  

SciTech Connect

As part of a broad ecological study of Kenyan pastoralist adaptation to periodic drought, a study was done to determine how arid region geomorphology affects hydrology and subsequently vegetative patterns. In this study area, 100 kilometers south of Lake Turkana, it appears that irregular precipitation is stored in bajada sediments and is available to deeply rooted vegetation over long periods of time. This vegetation provides a relatively constant food source for people's herds of browsers, the camels and goats, whereas cattle, which graze mainly on grasses, are significant producers only during wet seasons. Field observations suggest that the mountain and abutting pediment soils are too shallow to store appreciable water. However, greater quantities of water are stored in the deeper bajada sediments adjacent to the pediment where pastoralists dig temporary wells in ephemeral channels during wet seasons. Density of tree growth is greater along channels, and highest canopy cover values are found about the pediment-bajada interface. Geohydrologic processes in this area provide the basis for continuous occupation by the desert people, in contrast to recurring famines in adjacent areas, by enhancing the growth of woody vegetation.

Coppinger, K.D.; Doehring, D.O.; Schimel, D.S.

1985-01-01

89

Sensitivity of a semi-arid tropical lake basin to environmental changes (Lake Ihotry basin, South-West of Madagascar)  

NASA Astrophysics Data System (ADS)

The objective of the study is to analyse the sensitivity of water ressources in a large semi-arid catchment, based on few hydro-meteorological and satellite images analysis. The site is located in the south-west of Madagascar. The catchment, which surface is 3000 km^2, is limited in its eastern side by a North-south relief up to 1000m high. The most important part of the catchment is made of a sandy plain, with a very poorly structured hydrographic network. The average annual precipitation varies in the catchment from 600 mm in the plain to 1000 mm in the mountains, with an an average temperature of 25^oC and an annual potential evapotranspiration rate of almost 2000mm. In the plain, surface and subsurface water circulation converges to Lake Ihotry, which has no surface outlet. The lake, very shallow, usually undergoes hudge seasonnal and inter-annual variations in water surface (from 60 to 120 km^2) and in water conductivity (from 7 to 23 mS/cm). In the catchment, no river flow data are available, partly because of the great instability of the hydrographic network. A dynamic model of lake water and salinity balances is used to establish the lake water balance and the temporal variations of water inflows, based on the daily data of precipitation, lake level and pan evaporation obtained during a 3 years field measurement campain. These results provide indirect data for validating a catchment hydrological model. We present the first results of the application of a semi-distributed hydrological modelling approach based on the determination of hydrological response units (HRU). The analysis of four stereoscopic couples of panchromatic SPOT scenes (10m resolution), allows to elaborate a digital elevation model and a vegetation map. The cultivated areas represent more than 20% of the total surface of the catchment, that is more than half of the plain. The delineation of the HRU’s is mainly based on the vegetation map, which seems to be a good integrator of the combined effects of pedology, geology, and topography on hydrological caracteristics. The hydrologic connectivity between the different HRU’s is established using available geological and geomorphological data. The catchment model will be used to study the sensitivity of the hydrological system to environmental changes in the different types of HRU. Special attention will be paid to the impact of irrigated cultivation on water availability and water salinity.

Vallet-Coulomb, C.; Maurin, A.; Gasse, F.; Ferry, L.; Robison, L.

2003-04-01

90

Causality analysis of groundwater dynamics based on a Vector Autoregressive model in the semi-arid basin of Gundal (South India)  

NASA Astrophysics Data System (ADS)

Causal relationships existing between observed levels of groundwater in a semi-arid sub-basin of the Kabini River basin (Karnataka state, India) are investigated in this study. A Vector Auto Regressive model is used for this purpose. Its structure is built on an upstream/downstream interaction network based on observed hydro-physical properties. Exogenous climatic forcing is used as an input based on cumulated rainfall departure. Optimal models are obtained thanks to a trial approach and are used as a proxy of the dynamics to derive causal networks. It appears to be an interesting tool for analysing the causal relationships existing inside the basin. The causal network reveals 3 main regions: the Northeastern part of the Gundal basin is closely coupled to the outlet dynamics. The Northwestern part is mainly controlled by the climatic forcing and only marginally linked to the outlet dynamic. Finally, the upper part of the basin plays as a forcing rather than a coupling with the lower part of the basin allowing for a separate analysis of this local behaviour. The analysis also reveals differential time scales at work inside the basin when comparing upstream oriented with downstream oriented causalities. In the upper part of the basin, time delays are close to 2 months in the upward direction and lower than 1 month in the downward direction. These time scales are likely to be good indicators of the hydraulic response time of the basin which is a parameter usually difficult to estimate practically. This suggests that, at the sub-basin scale, intra-annual time scales would be more relevant scales for analysing or modelling tropical basin dynamics in hard rock (granitic and gneissic) aquifers ubiquitous in south India.

Mangiarotti, S.; Sekhar, M.; Berthon, L.; Javeed, Y.; Mazzega, P.

2012-08-01

91

Groundwater quality and management in arid and semi-arid regions: Case study, Central Eastern Desert of Egypt  

NASA Astrophysics Data System (ADS)

This study presents a model budget for groundwater in the Central Eastern Desert of Egypt. The stable isotopic composition and hydrochemistry of groundwater samples collected from different aquifers were determined to identify recharge sources and water quality. Stable isotopic values suggest that shallow alluvial and fracture zone aquifers are recharged from seasonal precipitation, while groundwater in deeper sedimentary sub-basins is paleowater that was recharged during periods of less arid regional climate. Hydrochemical analysis indicates elevated salinity in each aquifer type, which is attributed to leaching and dissolution of terrestrial salts and to mixing with marine water. Groundwater from sedimentary sub-basin aquifers can be treated and used for drinking and domestic purposes. Groundwater from shallow alluvial and fracture zone wells is suitable for animal husbandry and mineral ore dressing. A model water budget shows that approximately 4.8 × 109 m3 of recoverable groundwater is stored in sedimentary sub-basin aquifers, or approximately 550 years of water at present utilization rates.

Amer, Reda; Ripperdan, Robert; Wang, Tao; Encarnación, John

2012-07-01

92

PLS regression-based pan evaporation and minimum-maximum temperature projections for an arid lake basin in India  

NASA Astrophysics Data System (ADS)

Climate change information required for impact studies is of a much finer scale than that provided by Global circulation models (GCMs). This paper presents an application of partial least squares (PLS) regression for downscaling GCMs output. Statistical downscaling models were developed using PLS regression for simultaneous downscaling of mean monthly maximum and minimum temperatures ( T max and T min) as well as pan evaporation to lake-basin scale in an arid region in India. The data used for evaluation were extracted from the NCEP/NCAR reanalysis dataset for the period 1948-2000 and the simulations from the third-generation Canadian Coupled Global Climate Model (CGCM3) for emission scenarios A1B, A2, B1, and COMMIT for the period 2001-2100. A simple multiplicative shift was used for correcting predictand values. The results demonstrated that the downscaling method was able to capture the relationship between the premises and the response. The analysis of downscaling models reveals that (1) the correlation coefficient for downscaled versus observed mean maximum temperature, mean minimum temperature, and pan evaporation was 0.94, 0.96, and 0.89, respectively; (2) an increasing trend is observed for T max and T min for A1B, A2, and B1 scenarios, whereas no trend is discerned with the COMMIT scenario; and (3) there was no trend observed in pan evaporation. In COMMIT scenario, atmospheric CO2 concentrations are held at year 2000 levels. Furthermore, a comparison with neural network technique shows the efficiency of PLS regression method.

Goyal, Manish Kumar; Ojha, C. S. P.

2011-10-01

93

Remote sensing indices for monitoring land degradation in a semiarid to arid basin in Jordan  

NASA Astrophysics Data System (ADS)

Spectral reflectance for soils and vegetation of the Yarmouk basin were correlated with surficial soil properties and vegetation biomass and cover. The overall aim of the study was to identify bands suitable for assessing soil and vegetation as indices for land degradation and desertification. Results showed that vegetation was well separated from soils in the shortwave infrared wavelength at 1480 nm. For most sites, the differences in the bandwidths (in the range of 8.5 nm to 90 nm) did not improve the differentiation of vegetation types. For all wavelengths, stronger correlation values (maximum R2 = 0.85) were obtained for vegetation cover when compared with biomass (maximum R2 = 0.54). Soil spectral reflectance tended to increase with salinity, with maximum correlations obtained in the blue wavelengths (470±10 nm, 485±90 nm), followed by green and the NIR bands, where R2 values were around 0.60. Comparing results from radiometer measurements with results obtained from ASTER image bands showed that correlations tended to decrease with decreased spatial resolution for the investigated soil properties. For all wavelengths, spectral reflectance of degraded soils was higher than that for natural vegetation and irrigated crops with partial surface cover. Results of the study showed that the use of remote sensing indices related to vegetation cover and soil salinity would be recommended to map the extent of land degradation in the study area and similar environments. However, spectral unmixing should be applied to improve the correlations between satellite remote sensing data and surficial soil properties.

Al-Bakri, Jawad; Saoub, Hani; Nickling, William; Suleiman, Ayman; Salahat, Mohammad; Khresat, Saeb; Kandakji, Tareq

2012-10-01

94

Isotopic evidence for climatic influence on alluvial-fan development in Death Valley, California  

Microsoft Academic Search

At least three semiarid to arid cycles are recorded by ..delta..¹³C values of organic matter in layers of rock varnishes on surfaces of Hanaupah Canyon and Johnson Canyon alluvial fans, Death Valley, California. These isotopic paleoenvironmental signals are interpreted as indicating major periods of fan aggradation during relatively more humid periods and fan entrenchment during subsequent lengthy arid periods.

Ronald I. Dorn; M. J. DeNiro; H. O. Ajie

1987-01-01

95

Alluvial Fan Flooding.  

National Technical Information Service (NTIS)

This report addresses a wide range of issues related to alluvial fan flooding. Chapter 1 presents an introduction to why identification of alluvial fan flooding hazards is controversial and the problems of definitions. Chapter 2 looks in more depth at fan...

1996-01-01

96

Large to intermediate-scale aquifer heterogeneity in fine-grain dominated alluvial fans (Cenozoic As Pontes Basin, northwestern Spain): insight based on three-dimensional geostatistical reconstruction  

NASA Astrophysics Data System (ADS)

Facies reconstructions are used in hydrogeology to improve the interpretation of aquifer permeability distribution. In the absence of sufficient data to define the heterogeneity due to geological processes, uncertainties in the distribution of aquifer hydrofacies and characteristics may appear. Geometric and geostatistical methods are used to understand and model aquifer hydrofacies distribution, providing models to improve comprehension and development of aquifers. However, these models require some input statistical parameters that can be difficult to infer from the study site. A three-dimensional reconstruction of a kilometer scale fine-grain dominated Cenozoic alluvial fan derived from more than 200 continuously cored, closely spaced, and regularly distributed wells is presented. The facies distributions were reconstructed using a genetic stratigraphic subdivision and a deterministic geostatistical algorithm. The reconstruction is only slightly affected by variations in the geostatistical input parameters because of the high-density data set. Analysis of the reconstruction allowed identification in the proximal to medial alluvial fan zones of several laterally extensive sand bodies with relatively higher permeability; these sand bodies were quantified in terms of volume, mean thickness, maximum area, and maximum equivalent diameter. These quantifications provide trends and geological scenarios for input statistical parameters to model aquifer systems in similar alluvial fan depositional settings.

Falivene, O.; Cabrera, L.; Sáez, A.

2007-08-01

97

[Influence of soil salinization on soil animal community in an arid oasis of middle Heihe River basin].  

PubMed

An investigation was conducted on the status of soil salinization and the structure of soil animal community across six land use/cover types in an arid oasis of middle Heihe River basin, and the methods of redundancy analysis, regression analysis, and path analysis were adopted to analyze the responses of the soil animal community under different land use/cover types and different management modes to the various status of soil salinization. The six land use/cover types were 21-year old shrub land without irrigation and fertilization, 28-year old poplar and 33-year-old pine plantations with irrigation, 27- and 100-year-old farmlands with irrigation and fertilization, and natural grassland, from which all the other five land use/cover types were converted. The results demonstrated that land cover change in the absence of management practices did not lead to a significant change in the abundance and group richness of the soil animal community, while land cover change in the presence of management practices resulted in a significant change in the soil animal community. The evolvement of the soil animal community structure was co-affected by soil pH, soluble salt content, and Na+, Cl, HCO3-, and Mg2+ concentrations, among which, soil soluble salt and Na had the greatest contribution, being the key affecting factors. The abundance and group richness of the soil animal community had significant negative exponential correlations with soil soluble salt content and Na+ concentration, and significant quadratic correlations with soil Mg2+ and HCO3- concentrations. The calculated ecological threshold values of soil Mg2+ and HCO3- concentrations for the abundance and group richness of the soil animal community were 38.7-39.4 mg x kg(-1) and 324.9-335.3 mg x kg(-1), at which, the abundance and group richness reached their peaks 40-43 individuals x m(-2) and 13-14 families x m(-2), respectively. When the Mg2+ and HCO3- concentrations increased further, the abundance and group richness decreased. PMID:22937643

Liu, Ji-Liang; Li, Feng-Rui; Niu, Rui-Xue; Liu, Chang-An; Liu, Qi-Jun

2012-06-01

98

Using a physically-based model, tRIBS-Erosion, for investigating the effects of climate change in semi-arid headwater basins.  

NASA Astrophysics Data System (ADS)

Soil erosion due to rainfall detachment and flow entrainment of soil particles is a physical process responsible for a continuous evolution of landscapes. The rate and spatial distribution of this phenomenon depend on several factors such as climate, hydrologic regime, geomorphic characteristics, and vegetation of a basin. Many studies have demonstrated that climate-erosion linkage in particular influences basin sediment yield and landscape morphology. Although soil erosion rates are expected to change in response to climate, these changes can be highly non-linear and thus require mechanistic understanding of underlying causes. In this study, an integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of semi-arid headwater basins to climate change. Downscaled outputs of global circulation models are used to inform a stochastic weather generator that produces an ensemble of climate scenarios for an area in the Southwest U.S. The ensemble is used as input to the integrated model that is applied to different headwater basins of the Walnut Gulch Experimental Watershed to understand basin response to climate change in terms of runoff and sediment yield. Through a model application to multiple catchments, a scaling relationship between specific sediment yield and drainage basin area is also addressed and probabilistic inferences on future changes in catchment runoff and yield are drawn. Geomorphological differences among catchments do not influence specific changes in runoff and sediment transport that are mostly determined by precipitation changes. Despite a large uncertainty dictated by climate change projections and stochastic variability, sediment transport is predicted to decrease despite a non-negligible possibility of larger runoff rates.

Francipane, Antonio; Fatichi, Simone; Ivanov, Valeriy Y.; Noto, Leonardo V.

2013-04-01

99

Well-log signatures of alluvial-lacustrine reservoirs and source rocks, Lagoa-Feia Formations, Lower Cretaceous, Campos Basin, offshore Brazil  

Microsoft Academic Search

The Campos basin is situated in offshore southeastern Brazil. The Lagoa Feia is the basal formation in the stratigraphic sequence of the basin, and was deposited during rifting in an evolving complex of lakes of different sizes and chemical characteristics, overlying and closely associated with rift volcanism. The stratigraphic sequence is dominated by lacustrine limestones and shales (some of them

D. Abrahao; J. E. Warme

1988-01-01

100

Soil–water conservation and rainwater harvesting strategies in the semi-arid Mzingwane Catchment, Limpopo Basin, Zimbabwe  

Microsoft Academic Search

Various soil water management practices have been developed and promoted for the semi arid areas of Zimbabwe. These include a variety of infield crop management practices that range from primary and seconday tillage approaches for crop establishment and weed management through to land forming practices such as tied ridges and land fallowing. Tillage methods evaluated in this study include deep

Walter Mupangwa; David Love; Steve Twomlow

2006-01-01

101

Paired Catchment Modeling Study for a Monsoon Flood Event in Neighboring Semi-Arid Basins, New Mexico  

Microsoft Academic Search

Flooding in ephemeral stream networks can significantly impact channel geomorphology, sediment transport, biogeochemical cycles, and water availability for consumptive and recreational use. In order to better understand the spatial patterns of flooding, distributed models may provide an opportunity for further investigation of rainfall-runoff dynamics in headwater semi-arid catchments including flood generation in ungauged portions of a watershed. For example, the

R. L. Wyckoff; E. R. Vivoni

2005-01-01

102

Regional potentiometric-surface map of the Great Basin carbonate and alluvial aquifer system in Snake Valley and surrounding areas, Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada  

USGS Publications Warehouse

Water-level measurements from 190 wells were used to develop a potentiometric-surface map of the east-central portion of the regional Great Basin carbonate and alluvial aquifer system in and around Snake Valley, eastern Nevada and western Utah. The map area covers approximately 9,000 square miles in Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada. Recent (2007-2010) drilling by the Utah Geological Survey and U.S. Geological Survey has provided new data for areas where water-level measurements were previously unavailable. New water-level data were used to refine mapping of the pathways of intrabasin and interbasin groundwater flow. At 20 of these locations, nested observation wells provide vertical hydraulic gradient data and information related to the degree of connection between basin-fill aquifers and consolidated-rock aquifers. Multiple-year water-level hydrographs are also presented for 32 wells to illustrate the aquifer system's response to interannual climate variations and well withdrawals.

Gardner, Philip M.; Masbruch, Melissa D.; Plume, Russell W.; Buto, Susan G.

2011-01-01

103

The effect of vegetation and beaver dams on geomorphic recovery rates of incised streams in the semi-arid regions of the Columbia River basin, USA.  

NASA Astrophysics Data System (ADS)

Channel incision is a common occurrence in semi-arid regions of the Columbia River basin and throughout the world, where a fragile balance between climate, vegetation and geology makes channels susceptible to changes in hillslope erosion, stream discharge and sediment yield. Incision is defined as a rapid downcutting and lowering of the stream bed such that it reduces the frequency and duration of flooding onto the adjacent floodplain. We are studying the feasibility of restoring incised streams throughout the interior Columbia River basin. We hypothesize that under proper land use management, it is possible for them to aggrade such that they reconnect to their former floodplains within relatively short time frames. Theoretical and empirical evidence suggests that over decadal time scales, changes to land management that excludes grazing and allows riparian vegetation to become established can cause significant fill within the incised valleys. Preliminary modeling suggests that factors most affecting the length of time for an incised valley to completely aggrade and reconnect to its pre-incision floodplain are the depth of the incision, sediment production in the watershed, the amount and type of riparian vegetation, and the extent of beaver dam construction. While most natural resource and fisheries managers are aware of widespread incision throughout the Columbia River basin, the extent of incision within the range of the Pacific salmon is largely undocumented. However, we do know many incised streams that historically supported salmon no longer do so, and that habitat conditions are severely degraded in these incised streams. The historical record shows that numerous salmon-bearing streams in the semi-arid region of the interior Columbia River basin once contained narrow and deep, slowly meandering channels lined with cottonwoods, willows and/or sedges, contained numerous beaver dams, contained abundant and easily accessible off-channel habitat on the floodplain and had good flow and cool temperatures throughout most of the year. Today most of these streams are incised and contain little or no riparian vegetation or beaver dams. Stream temperatures are high and flow is ephemeral. Incision is thought to have lowered stream-adjacent water tables, causing both the loss of riparian vegetation and the increase in stream temperature. Many of these streams no longer support fish populations. We hypothesize that if incised streams were restored by creating conditions such that they could aggrade and reconnect to their former floodplains, that habitat conditions would be sufficient to again support salmon populations, and that this would greatly expand their range throughout much of the Columbia River basin.

Pollock, M.; Beechie, T.; Jordan, C.

2005-05-01

104

Enhanced sediment delivery in a changing climate in semi-arid mountain basins: Implications for water resource management and aquatic habitat in the northern Rocky Mountains  

NASA Astrophysics Data System (ADS)

The delivery and transport of sediment through mountain rivers affects aquatic habitat and water resource infrastructure. While climate change is widely expected to produce significant changes in hydrology and stream temperature, the effects of climate change on sediment yield have received less attention. In the northern Rocky Mountains, we expect climate change to increase sediment yield primarily through changes in temperature and hydrology that promote vegetation disturbances (i.e., wildfire, insect/pathogen outbreak, drought-related die off). Here, we synthesize existing data from central Idaho to explore (1) how sediment yields are likely to respond to climate change in semi-arid basins influenced by wildfire, (2) the potential consequences for aquatic habitat and water resource infrastructure, and (3) prospects for mitigating sediment yields in forest basins. Recent climate-driven increases in the severity and extent of wildfire suggest that basin-scale sediment yields within the next few years to decades could be greater than the long-term average rate of 146 T km - 2 year - 1 observed for central Idaho. These elevated sediment yields will likely impact downstream reservoirs, which were designed under conditions of historically lower sediment yield. Episodic erosional events (massive debris flows) that dominate post-fire sediment yields are impractical to mitigate, leaving road restoration as the most viable management opportunity for offsetting climate-related increases in sediment yield. However, short-term sediment yields from experimental basins with roads are three orders of magnitude smaller than those from individual fire-related events (on the order of 10 1 T km - 2 year - 1 compared to 10 4 T km - 2 year - 1 , respectively, for similar contributing areas), suggesting that road restoration would provide a relatively minor reduction in sediment loads at the basin-scale. Nevertheless, the ecologically damaging effects of fine sediment (material < 6 mm) chronically produced from roads will require continued management efforts.

Goode, Jaime R.; Luce, Charles H.; Buffington, John M.

2012-02-01

105

Alluvial Fan in Icaria Planum, Mars  

NASA Astrophysics Data System (ADS)

The Mars Express HRSC data were used to study fluvial history of southern Claritas on Mars (1, 2). Volatiles, transported downslope to the basin, breached through a saddle valley and formed a channel towards Icaria Planum in the west. Along the channel, sapping provided additional water. The channel broke into a 30-km impact crater and formed a temporary lake. The crater rim has terraces and the floor has smooth deposits. A delta was formed in a standing water. After breaching the crater rim through a neck which is higher than the crater floor, water deposited onto Icaria Planum an alluvial fan. This fan was studied using the HRSC colour data by mapping deposit units of the Icaria lowlands in front of the channel. The flood deposits were made visible by the multichannel HRSC data classification. The alluvial structures reflect topography and regional slopes as well as the amount of available water. The hi-resolution HRSC image provides an additional view into the alluvial structures, erosion and sedimentation in the channel formation. These remote sensing approaches facilitate the mapping of characteristic phases in the fluvial development of the area studied. References. (1) Raitala et al., 2005. LPS XXXVI, #1307. (2) Korteniemi, J., Raitala, J., Aittola, M., Kostama V.-P., Hauber E., Kronberg P., Neukum G. and the HRSC Co-I Team, 2005. Fluvial channel resulted in alluvial fan formation in Icaria Planum, Mars. Submitted to 42nd Vernadsky-Brown Microsymposium, Moscow 9-12. 10. 2005.

Korteniemi, J.; Raitala, J.; Aittola, M.; Kostama, V.; Hauber, E.; Kronberg, P.; Neukum, G.; HRSC Co-I Team

2005-12-01

106

Geomorphological evolution of the Tilcara alluvial fan (Jujuy Province, NW Argentina): Tectonic implications and palaeoenvironmental considerations  

Microsoft Academic Search

The development and evolution of the Tilcara alluvial fan, in the Quebrada de Humahuaca (Andean Eastern Cordillera, NW Argentina), has been analysed by using geomorphological mapping techniques, sedimentological characterisation of the deposits and OSL chronological methods. It is a complex segmented alluvial fan made up of five evolutionary stages (units Qf1, Qf2, Qf3, Qf4 and Qf5) developed under arid climatic

Carlos Sancho; José Luis Peña; Felipe Rivelli; Ed Rhodes; Arsenio Muñoz

2008-01-01

107

The problems of overexploitation of aquifers in semi-arid areas: the Murcia Region and the Segura Basin (South-east Spain) case  

NASA Astrophysics Data System (ADS)

A general analysis of the problems arising from aquifer exploitation in semi-arid areas such as the Autonomous Region of Murcia, which belongs to the Segura Basin is presented, with particular reference to the Ascoy-Sopalmo aquifer, which is the most overexploited aquifer in Spain. It has suffered intense overabstraction over the last forty years, given renewable water resources of 2 Mm3 yr-1 and abstractions amounting to as much as 55 Mm3 yr-1. This has resulted in the drying of springs, continuous drawdown of water levels (5 m yr-1); piezometric drops (over 30 m in one year, as a consequence of it being a karstic aquifer); increase in pumping costs (elevating water from more than 320 m depth); abandoning of wells (45 reduced to 20), diminishing groundwater reserves, and deteriorating water quality (progressing from a mixed sodium bicarbonate-chloride facies to a sodium chloride one). This is a prime example of poor management with disastrous consequences. In this sense, a series of internal measures is proposed to alleviate the overexploitation of this aquifer and of the Segura Basin, with the aim of contributing to a sustainable future.

Rodríguez-Estrella, T.

2012-05-01

108

Responses of surface runoff to climate change and human activities in the arid region of central Asia: a case study in the Tarim River basin, China.  

PubMed

Based on hydrological and climatic data and land use/cover change data covering the period from 1957 to 2009, this paper investigates the hydrological responses to climate change and to human activities in the arid Tarim River basin (TRB). The results show that the surface runoff of three headstreams (Aksu River, Yarkant River and Hotan River) of the Tarim River exhibited a significant increasing trend since 1960s and entered an even higher-runoff stage in 1994. In the contrary, the surface runoff of Tarim mainstream displayed a persistent decreasing trend since 1960s. The increasing trend of surface runoff in the headstreams can be attributed to the combined effects of both temperature and precipitation changes during the past five decades. But, the decreasing trend of surface runoff in the mainstream and the observed alterations of the temporal and spatial distribution patterns were mainly due to the adverse impacts of human activities. Specifically, increasingly intensified water consumption for irrigation and the associated massive constructions of water conservancy projects were responsible for the decreasing trend of runoff in the mainstream. And, the decreasing trend has been severely jeopardizing the ecological security in the lower reaches. It is now unequivocally clear that water-use conflicts among different sectors and water-use competitions between upper and lower reaches are approaching to dangerous levels in TRB that is thus crying for implementing an integrated river basin management scheme. PMID:23377191

Xu, Changchun; Chen, Yaning; Chen, Yapeng; Zhao, Ruifeng; Ding, Hui

2013-02-03

109

Large wood dynamics and biophysical consequences for riparian forests: A comparison of an unconfined alluvial river in a temperate rainforest and a bedrock confined river in a semi-arid South African savanna.  

NASA Astrophysics Data System (ADS)

Large wood shapes the geomorphology and ecology of rivers. We determined the origin, distribution, and fate of large wood in two rivers from contrasting environments. The Queets is an unstable temperate, rainforest river running from the Olympic Mountains (USA) through a glacial valley with colossal trees. In most years, the channel erodes a variety of forested landforms which forms jams that sculpt habitats. Many are displaced in a few years. Remaining jams initiate landform development and forest renewal. Thus, wood is stockpiled in the floodplain where it may become buried. Channel movements recapture most logs within 50 years. In contrast, the Sabie is a perennial river running through a confined bedrock channel in a fire-prone semi-arid South African savanna. Riparian trees are relatively small and many sink in water. A recent flood (February 2000) devastated the riparian forest, introducing wood to the channel. Jams formed on toppled trees, transported logs, and bedrock outcrops. Many trees survived and resprouted. Jams facilitated the establishment of woody plant seedlings and the intrusion of fire into riparian areas. Sunken wood formed unique depositional features. The Queets and Sabie rivers are strikingly different systems. However, large wood appears to promote the renewal and development of complex riparian forests in both rivers.

Latterell, J. J.; Pettit, N. E.; Naiman, R. J.

2005-05-01

110

(Plio-)Pleistocene alluvial-lacustrine basin infill evolution in a strike-slip active zone (Northern Andes, Western-Central Cordilleras, Colombia)  

Microsoft Academic Search

The (Plio)-Pleistocene Zarzal Formation was deposited in the Cauca Depression and Quindío-Risaralda Basin between the Western and Central Cordilleras (Northern Andes). This area is structurally located on the transcur- rent Romeral Fault System (RFS). Because of the interaction between the Nazca plate and the Chocó-Panamá block (an active indenter), the RFS strike-slip component changes direction around the study zone (dextral

F. SUTER R. NEUWERTH; G. GORIN; C. GUZMÁN

2008-01-01

111

Nuclear-waste isolation in the unsaturated zone of arid regions  

SciTech Connect

The vadose zone in arid regions is considered as a possible environment for geologic isolation of nuclear waste. There are several topographic and lithologic combinations in the vadose zone of arid regions that may lend themselves to waste isolation considerations. In some cases, topographic highs such as mesas and interbasin ranges - comprised of several rock types, may contain essentially dry or partially saturated conditions favorable for isolation. The adjacent basins, especially in the far western and southwestern US, may have no surface or subsurface hydrologic connections with systems ultimately leading to the ocean. Some rock types may have the favorable characteristics of very low permeability and contain appropriate minerals for the strong chemical retardation of radionuclides. Environments exhibiting these hydrologic and geochemical attributes are the areas underlain by tuffaceous rocks, relatively common in the Basin and Range geomorphic province. Adjacent valley areas, where tuffaceous debris makes up a significant component of valley fill alluvium, may also contain thick zones of unsaturated material, and as such also lend themselves to strong consideration as respository environments. This paper summarizes the aspects of nuclear waste isolation in unsaturated regimes in alluvial-filled valleys and tuffaceous rocks of the Basin and Range province.

Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

1982-05-01

112

Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front  

Microsoft Academic Search

Controversy exists over whether alluvial-fan sedimentation along tectonically active mountain fronts is driven by climatic changes or tectonics. Knowing the age of sedimentation is the key to understanding the relationship between sedimentation and its cause. Alluvial-fan deposits in Death Valley and throughout the arid southwestern United States have long been the subjects of study, but their ages have generally eluded

M. F. Sohn; S. A. Mahan; J. R. Knott; D. D. Bowman

2007-01-01

113

Using cosmogenic nuclides to contrast rates of erosion and sediment yield in a semi-arid, arroyo-dominated landscape, Rio Puerco Basin, New Mexico  

USGS Publications Warehouse

Analysis of in-situ-produced 10Be and 26Al in 52 fluvial sediment samples shows that millennial-scale rates of erosion vary widely (7 to 366 m Ma-1) through the lithologically and topographically complex Rio Puerco Basin of northern New Mexico. Using isotopic analysis of both headwater and downstream samples, we determined that the semi-arid, Rio Puerco Basin is eroding, on average, about 100 m Ma-1. This rapid rate of erosion is consistent with estimates made using other techniques and is likely to result from a combination of easily eroded lithologies, sparse vegetation, and monsoon-dominated rainfall. Data from 331 stream water samples collected by the US Geological Survey between 1960 and 1995 are consistent with basin-wide, average chemical denudation rates of only about 1??4 m Ma-1; thus, the erosion rates we calculate may be considered rates of sediment generation because physical weathering accounts for almost 99 per cent of mass loss. The isotopic data reveal that sediment is generally well mixed downstream with the area-weighted average sediment generation rate for 16 headwater samples (234 ton km-2 a-1 for basin area 170 to 1169 km2) matching well that estimated from a single sample collected far downstream (238 ton km-2 a-1, basin area = 14 225 km2). A series of 15 samples, collected from an arroyo wall and representing deposition through the late Holocene, indicates that 10Be concentration in sediment delivered by the fluvial system has not changed appreciably over the last 1200 years despite at least two cycles of arroyo cutting and filling. Other samples (n = 21) were collected along the drainage network. Rio Puerco erosion rates scale directly with a variety of metrics describing vegetation, precipitation, and rock erodibility. Using the headwater basins for calibration, the erosion rates for both the downstream samples and also the data set as a whole, are best modelled by considering a combination of relief and vegetation metrics, both of which co-vary with precipitation and erodibility as inferred from lithology. On average, contemporary sediment yields, determined by monitoring suspended-sediment discharge, exceed cosmogenically determined millennial-scale erosion rates by nearly a factor of two. This discrepancy, between short-term rates of sediment yield and long-term rates of erosion, suggests that more sediment is currently being exported from the basin than is being produced. Because the failure of incised channel walls and the head cutting of arroyo complexes appear to be the main sources of channel sediment today, this incongruence between rates of sediment supply and sediment yield is likely to be transitory, reflecting the current states of the arroyo cycle and perhaps the influence of current or past land-use patterns. Copyright ?? 2005 John Wiley & Sons, Ltd.

Bierman, P. R.; Reuter, J. M.; Pavich, M.; Gellis, A. C.; Caffee, M. W.; Larsen, J.

2005-01-01

114

An ostracod-inferred large Middle Pleistocene freshwater lake in the presently hyper-arid Qaidam Basin (NW China)  

Microsoft Academic Search

Exposed sediments of 50m thickness were investigated in the 120,000km2 Qaidam Basin at the northern margin of the Tibetan Plateau. Fine-grained silty sediments constitute most of the section and were accumulated in a lake. Intercalated beds of aeolian sand, and of fluvial or littoral origin, show that the lake experienced periods of desiccation and shallow water levels at the section

Steffen Mischke; Zhencheng Sun; Ulrike Herzschuh; Zizhen Qiao; Naida Sun

2010-01-01

115

Stable isotopes of lake and fluid inclusion brines, Dabusun Lake, Qaidam Basin, western China: Hydrology and paleoclimatology in arid environments  

Microsoft Academic Search

The Qaidam Basin, underlain by salt, is the largest (120,000 km2) on the Qinghai-Tibet Plateau, western China. Numerous shallow to ephemeral saline lakes and dry saline pans are present on the Qarhan Salt Plain. Dabusun Lake, the largest (about 200 km2), contains high salinity Na?Mg?Cl brines. Whereas it precipitates halite, it is fringed by a potash salt flat.The dominant inflow

Wenbo Yang; Ronald J. Spencer; H. Roy Krouse; Tim K. Lowenstein; E. Casas

1995-01-01

116

A debris flow deposit in alluvial, coal-bearing facies, Bighorn Basin, Wyoming, USA: Evidence for catastrophic termination of a mire  

USGS Publications Warehouse

Coal and clastic facies investigations of a Paleocene coal-bearing succession in the Grass Creek coal mine, southwestern Bighorn Basin, Wyoming, USA, suggest that disruption of peat accumulation in recurrent mires was caused by the repetitive progradation of crevasse splays and, ultimately, by a catastrophic mass movement. The mass movement, represented by deposits of debris flow, marked the termination of significant peat accumulation in the Grass Creek coal mine area. Megascopic and microscopic analyses of coal beds exposed along the mine highwalls suggest that these deposits developed in low-lying mires, as evidenced primarily by their ash yields and maceral composition. Disruption of peat accumulation in successive mires was caused by incursions of sediment into the mire environments. Termination by crevasse splay progradation is represented by coarsening-upward successions of mudrock and tabular, rooted sandstone, which overlie coal beds in the lower part of the coal-bearing interval. A more rapid process of mire termination by mass movement is exemplified by a debris flow deposit of diamictite, which overlies the uppermost coal bed at the top of the coal-bearing interval. The diamictite consists of a poorly sorted, unstratified mixture of quartzite cobbles and pebbles embedded in a claystone-rich or sandy mudstone matrix. Deposition of the diamictite may have taken place over a matter of weeks, days, or perhaps even hours, by catastrophic flood, thus reflecting an instantaneous process of mire termination. Coarse clastics and mud were transported from the southwest some 20-40 km as a viscous debris flow along stream courses from the ancestral Washakie Range to the Grass Creek area, where the flow overrode a low-lying mire and effectively terminated peat accumulation. ?? 1994.

Roberts, S. B.; Stanton, R. W.; Flores, R. M.

1994-01-01

117

Phosphorous concentration, solubility and species in the groundwater in a semi-arid basin, southern Malayer, western Iran  

NASA Astrophysics Data System (ADS)

In areas of intensive crop production, continual phosphorous (P) applications as P fertilizer and farmyard manure have been made at levels exceeding crop requirement. As a result, surface soil accumulations of P have occurred to such an extent that loss of P in surface runoff and a high risk for P transfer into groundwater in concentrations exceeding the groundwater quality standard has become a priority management concern. Phosphorous content of groundwater was determined in order to examine dissolved P concentration and species in the groundwater and mineral solubilitiy in a semi-arid region of southern Malayer, western Iran. The speciation for P in groundwater was calculated using geochemical speciation model PHREEQC. The concentration of total P in the groundwater (0.01-2.56 mg P l-1) and estimated concentrations of HPO4 2- (49.5-89%), H2PO4 - (1.5-17.3%), CaHPO4 + (5.7-36.1%), and CaPO4 - (1.4-12.2%) varied considerably amongst the groundwater. Results suggest that the concentration of P in the groundwater could be primarily controlled by the solubility of octacalcium phosphate and ?-tricalcium phosphate. Large amounts of P fertilizer, inadequate management of P fertilization, and low irrigation efficiency, coupled with sandy soils in some parts of the study area could be mainly responsible for the greater P in the groundwater. In general, the greater the dissolved P concentration in the groundwater, the closer the solution was to equilibrium with respect to the more soluble Ca-phosphate minerals. The groundwater P content could be potentially used to identify areas where management approaches, such as P applied and crop type planted, could be adjusted to different types of soils, geology and topography.

Jalali, Mohsen

2009-05-01

118

Combining SAR with LANDSAT for Change Detection of Riparian Buffer Zone in a Semi-arid River Basin  

NASA Astrophysics Data System (ADS)

A combination of RADARSAT-1 and Landsat 5 TM satellite images linking the soil moisture variation with Normalized Difference Vegetation Index (NDVI) measurements were used to accomplish remotely sensed change detection of riparian buffer zone in the Choke Canyon Reservoir Watershed (CCRW), South Texas. The CCRW was selected as the study area contributing to the reservoir, which is mostly agricultural and range land in a semi-arid coastal environment. This makes the study significant due to the interception capability of non-point source impact within the riparian buffer zone and the maintenance of ecosystem integrity region wide. First of all, an estimation of soil moisture using RADARSAT-1 Synthetic Aperture Radar (SAR) satellite imagery was conducted. With its all-weather capability, the RADARSAT-1 is a promising tool for measuring the surface soil moisture over seasons. The time constraint is almost negligible since the RADARSAT-1 is able to capture surface soil moisture over a large area in a matter of seconds, if the area is within its swath. RADARSAT-1 images presented at here were captured in two acquisitions, including April and September 2004. With the aid of five corner reflectors deployed by Alaska Satellite Facility (ASF), essential radiometric and geometric calibrations were performed to improve the accuracy of the SAR imagery. The horizontal errors were reduced from initially 560 meter down to less than 5 meter at the best try. Then two Landsat 5 TM satellite images were summarized based on its NDVI. The combination of and NDVI and SAR data obviously show that soil moisture and vegetation biomass wholly varies in space and time in the CCRW leading to identify the riparian buffer zone evolution over seasons. It is found that the seasonal soil moisture variation is highly tied with the NDVI values and the change detection of buffer zone is technically feasible. It will contribute to develop more effective management strategies for non-point source pollution control, bird habitat monitoring, and grazing and live stock handlings in the future. Future research focuses on comparison of soil moisture variability within RADARSAT-1 footprints and NDVI variations against interferometric SAR for studying riparian ecosystem functioning on a seasonal basis.

Chang, N.

2006-12-01

119

Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai-Tibetan Plateau  

NASA Astrophysics Data System (ADS)

Permafrost on the Qinghai-Tibetan Plateau (QTP) has degraded over the last few decades. Its ecological effects have attracted great concern. Previous studies focused mostly at plot scale, and hypothesized that degradation of permafrost would cause lowering of the water table and drying of shallow soil and then degradation of alpine grassland. However, none has been done to test the hypothesis at basin scale. In this study, for the first time, we investigated the relationships between land surface temperature (LST) and fractional vegetation cover (FVC) in different types of permafrost zone to infer the limiting condition (water or energy) of grassland growth on the source region of Shule River Basin, which is located in the north-eastern edge of the QTP. LST was obtained from MODIS Aqua products at 1 km resolution, while FVC was upscaled from quadrat (50 cm) to the same resolution as LST, using 30 m resolution NDVI data of the Chinese HJ satellite. FVC at quadrat scale was estimated by analyzing pictures taken with a multi-spectral camera. Results showed that (1) retrieval of FVC at quadrat scale using a multi-spectral camera was both more accurate and more efficient than conventional methods and (2) the limiting factor of vegetation growth transitioned from energy in the extreme stable permafrost zone to water in the seasonal frost zone. Our study suggested that alpine grassland would respond differently to permafrost degradation in different types of permafrost zone. Future studies should consider overall effects of permafrost degradation, and avoid the shortcomings of existing studies, which focus too much on the adverse effects.

Yi, Shuhua; Zhou, Zhaoye; Ren, Shilong; Xu, Ming; Qin, Yu; Chen, Shengyun; Ye, Baisheng

2011-10-01

120

A Basin-Averaged Water Balance Approach to Estimate Catchment-Scale Groundwater Flow in a Semi-arid Mountainous Catchment  

Microsoft Academic Search

Quantification of the contribution of groundwater flow from highland areas of mountainous watersheds to semi-arid and arid valley bottom unconsolidated aquifers is increasingly needed for the assessment of water resources in many populated areas. In mountainous environments, however, data for Darcy equation parameters are limited, leading to uncertainty in estimates of groundwater flow of up to two or more orders

L. A. Neilson-Welch; R. Allard; D. Geller; D. M. Allen

2008-01-01

121

Climatic and Tectonic Controls on Alluvial Fan Evolution: The Lost River Range, Idaho  

NASA Astrophysics Data System (ADS)

In the northern Basin &Range, alluvial fans developed along the Lost River range-front consist of several distinct inset fan segments with concave-up radial profiles. Multiple large radius (>5 km), shallow (2- 3°), alluvial fans extend across and beyond the active, ~140-km-long, normal Lost River fault. These large fans are relict features, formed by major sheetfloods that occurred intermittently between ~15-180 ka. More recent deposition has been dominated by debris-flows that form small-radius (<2 km), steep (8- 17°), fans closely confined to the mountain front [1,2]. In order to determine the timing of fan surface stabilization, we have undertaken precise mass spectrometric 230Th/U dating of pedogenic carbonate from calcic soils that mantle fan surfaces on the Arco fault segment. Careful selection of mg-size samples of dense soil carbonate pebble coats, from within a trench that cuts through gravelly fan deposits, indicates that the fan soils are geochemically suitable for uranium-series dating (median U=7ppm, 232Th=0.09ppm, 232Th/230Th=154). 230Th/U analysis of these calcic soils can thus provide precise temporal constraints on intervals of surface stability and subsequent soil formation. The oldest fan surface (Qfo1, 178+/-8 ka), exposed within the footwall of the trench, suggests an interval of surface stability, indicating that the fan was likely abandoned due to incision early in MIS 6. Incision may have resulted from surface faulting along the Arco segment of the Lost River fault, but could relate to changes in stream power or sediment supply associated with climatic change or with auto-cyclic variations within the drainage basin. A younger incised and faulted fan surface (Qfo2, 69+/-6 ka), likely represents active alluviation at the beginning of MIS 4 and, since it formed as hanging-wall alluvial gravel, provides age limits on an episode of fault displacement between Qfo1 and Qfo2. In situ pedogenic carbonate coats on sub-angular gravels within the colluvial fault wedge date at 68+/-2 ka, suggesting that either faulting occurred soon after Qfo2 stabilized or that soil carbonate coats were recycled into the colluvial wedge from the faulted surface. Further studies in the Lost River Range will assess the timing of fan deposition, surface stabilization and fault activity since the late Pleistocene using coupled application of Optically Stimulated Thermoluminescence (OSL) dating of loess and fine-sands, and 230Th/U-dating of pedogenic carbonate formed within well- exposed fan stratigraphy. Defining intervals of erosion, deposition and stability within the context of regional records of Quaternary climate change will yield new insights into the interplay between faulting, climate change and alluvial fan deposition and incision in semi-arid environments. [1] Pierce, K.L., Scott, W.E., 1982. Idaho Mines &Geol. Bull. 26. [2] Patterson, S.J., 2006. M.S. Thesis, Montana State University

Phillips, R. J.; Pierce, J. L.; Sharp, W. D.; Pierce, K. L.

2006-12-01

122

The Tabernas alluvial fan and lake system, southeast Spain: applications of mineral magnetic and pedogenic iron oxide analyses towards clarifying the Quaternary sediment sequences  

Microsoft Academic Search

Mineral magnetic and soil iron oxide data are applied to questions of relative age correlation of alluvial fans and lake sediments in the Tabernas basin, southeast Spain, within a context of interaction between tectonics and climatic change. Within the Tabernas basin, the sediment sequences and morphological evolution of late Quaternary alluvial fans suggest climatic change as the primary control. The

Adrian M Harvey; Gez Foster; Jack Hannam; Anne E Mather

2003-01-01

123

Point sources of emerging contaminants along the Colorado River Basin: source water for the arid Southwestern United States.  

PubMed

Emerging contaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the United States. The objective of this study was to evaluate point sources of ECs along the Colorado River, from the headwaters in Colorado to the Gulf of California. At selected locations in the Colorado River Basin (sites in Colorado, Utah, Nevada, Arizona, and California), waste stream tributaries and receiving surface waters were sampled using either grab sampling or polar organic chemical integrative samplers (POCIS). The grab samples were extracted using solid-phase cartridge extraction (SPE), and the POCIS sorbents were transferred into empty SPEs and eluted with methanol. All extracts were prepared for, and analyzed by, liquid chromatography-electrospray-ion trap mass spectrometry (LC-ESI-ITMS). Log D(OW) values were calculated for all ECs in the study and compared to the empirical data collected. POCIS extracts were screened for the presence of estrogenic chemicals using the yeast estrogen screen (YES) assay. Extracts from the 2008 POCIS deployment in the Las Vegas Wash showed the second highest estrogenicity response. In the grab samples, azithromycin (an antibiotic) was detected in all but one urban waste stream, with concentrations ranging from 30ng/L to 2800ng/L. Concentration levels of azithromycin, methamphetamine and pseudoephedrine showed temporal variation from the Tucson WWTP. Those ECs that were detected in the main surface water channels (those that are diverted for urban use and irrigation along the Colorado River) were in the region of the limit-of-detection (e.g., 10ng/L), but most were below detection limits. PMID:22684090

Jones-Lepp, Tammy L; Sanchez, Charles; Alvarez, David A; Wilson, Doyle C; Taniguchi-Fu, Randi-Laurant

2012-06-08

124

Large alluvial fans on Mars  

Microsoft Academic Search

Several dozen distinct alluvial fans, 10 to ?40 km long downslope, have been observed in highlands craters. Within a search region between 0° and 30°S, alluvial fan-containing craters were found only between 18° and 29°S, and they all occur at around ±1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form

Jeffrey M. Moore; Alan D. Howard

2005-01-01

125

Alluvial Fans as Recorders of Landscape Development: Potential for Determining Depositional Chronologies Using Luminescence Dating  

NASA Astrophysics Data System (ADS)

Alluvial fans in both arid and humid environments provide a record of depositional events at the transition between mountain and lowland environments. Though complex in the detail of their depositional and erosional characteristics, they undoubtedly provide a valuable record of the highest erosion rate events in their upland catchments. Alluvial fans often also record tectonic activity; their mountain-front location is ideal to intersect bounding faults, and their characteristic geometry renders offsets easily recognisable. Dating of Quaternary alluvial fans can be accomplished using a number of techniques. These include radiocarbon dating where suitable organic materials are preserved; uranium series methods may be applied to provide a minimum age by dating carbonate inter-clast cements in some arid or semi-arid environments; terrestrial cosmogenic nuclide (TCN) methods work well in many dryland contexts though issues of inheritance in some catchments are significant. Optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) rely on light sensitive charge populations trapped at meta-stable centers associated with impurities in quartz and feldspar grains. When grains are exposed to light, charge is evicted from these traps, and is slowly re-tapped by interaction with environmental ionizing radiaton. These signals have the potential to date a range of Quaternary sediments including alluvial fans on timescales of one year to several hundred thousand years. The specific issues relating to alluvial fans are problems of incomplete signal zeroing caused by rapid deposition, as well as low sensitivity and poor signal characteristics for quartz OSL. In this presentation, we explore the relative importance of these issues in determining luminescence chronologies for alluvial fans in different locations, and the ways in which these chronologies may be used to help inform models of landscape evolution, both numerical and conceptual.

Lawson, M. J.; Rhodes, E. J.; Roder, B. J.; Antinao, J.; McDonald, E.

2011-12-01

126

Climatic and Tectonic Controls on Alluvial Fan Evolution: The Lost River Range, Idaho  

Microsoft Academic Search

In the northern Basin &Range, alluvial fans developed along the Lost River range-front consist of several distinct inset fan segments with concave-up radial profiles. Multiple large radius (>5 km), shallow (2- 3°), alluvial fans extend across and beyond the active, ~140-km-long, normal Lost River fault. These large fans are relict features, formed by major sheetfloods that occurred intermittently between ~15-180

R. J. Phillips; J. L. Pierce; W. D. Sharp; K. L. Pierce

2006-01-01

127

Monti Martani (umbria, Italy) Alluvial Fans: Hazards Sites and Occurrence  

Microsoft Academic Search

In this paper we proposed modeling and simulation approaches for testing the debris flows occurrence hypothesis. The approach is an empirically and process based, and use multiple physically-based simulations to evaluate hazard down-slope from initiation sites in alluvial fans of the Terni basin-northern area (Umbria, Italy). The northern part of the area is bounded by the M. Martani normal fault

A. Taramelli; L. Melelli

2002-01-01

128

Large Alluvial Fans in the Araba Valley (Jordan) as a Record of Tectonic Deformation of the Southern Dead Sea Fault and Regional Paleoclimates  

NASA Astrophysics Data System (ADS)

The Dead Sea fault is the 1000 km-long strike-slip fault that accommodates northward motion of Arabia relative to Sinai at a rate of about 5 mm/yr. This study focuses on the southern segment of this fault, the Wadi Araba fault. From the Dead Sea basin to the Gulf of Aqaba, the fault runs along an axial valley, about 20 km wide and 150 km long, bounded to the east by the Jordanian Plateau, reaching 1500 m in elevation and to the west by the Negev Plateau, lower in elevation (500-700 m). The Araba valley is floored with Plio-Quaternary deposits and in particular with large alluvial fans that are cut by the fault and offset relative to their feeding channel. We mapped the valley floor in details and dated some of these fans first to assess their lateral offset and further constrain the slip rate on the fault, and secondly to try to correlate alluvial fan aggradation periods in this arid/semi-arid environment to paleoclimatic variations at the regional and global scales. To identify the possible sources of the large alluvial fans, we analyzed the drainage network and the catchment basins on the valley rims based on SRTM3 topography. Previous study suggested that these fans were Pliocene and underwent offsets of 15 to 30 km. Ages as young as 50 to 350 kyr derived from 10Be exposure dating of 33 samples from the surface of some of these fans indicate that such offsets are very unlikely. Actual offsets have to be smaller. Preliminary reconstructions suggest offsets of 700-1300 m and 1600-2000 m for fans dated at 160 +/- 20 kyr and 330 +/- 22 kyr respectively, and offsets of 2.5-3.5 and 4.4-5.4 km for older fans that have not been dated yet. Consistent ages at different sites suggest simultaneous fan emplacement controlled by some external controlling factor such as climate variations. The correlation between these aggradation episodes and paleoclimatic variations would allow us to draw hypotheses on the age of these older surfaces. These preliminary results provide new constraints on the slip rate of the fault of 4-9 mm/yr since the Middle to Late Pleistocene.

Le Beon, M.; Klinger, Y.; Al-Qaryouti, M.; Meriaux, A.; Finkel, R. C.; Mayyas, O.; Ryerson, F. J.; Tapponnier, P.

2007-12-01

129

Sedimentology of Holocene debris flow-dominated alluvial fans, northwest Wyoming: Contributions to alluvial fan facies models  

SciTech Connect

Facies models for debris flow-dominated alluvial fans are based exclusively upon studies of relatively few fans in the arid American southwest. Detailed geomorphic, stratigraphic, and sedimentologic analyses of several highly-active, debris flow-dominated alluvial fans in northern Yellowstone National Park, WY (temperature, semi-arid) serve to diversify and increase the usefulness of alluvial fan facies models. These fans display an intricate distributary pattern of incised active (0--6 m deep; 700--900 m long) and abandoned channels (1--4 m deep; 400 m long) with levees/levee complexes (<3 m high; <20 m wide; <750 m long) and lobes constructed by pseudoplastic to plastic debris flows. The complex pattern of debris flow deposits is due to repeated channel back filling and overtopping by debris flows behind in-channel obstructions which subsequently lead to channel abandonment. Debris-flow deposition is dominant due to: (1) small, steep (up to 35 degrees) source area catchments, (2) extensive mud rock outcrops in the source area, and (3) episodic summer rainfall events. Proximal to distal fan surfaces exhibit sheetflood deposits several cm thick and up to 70 m in lateral extent. Vertical lithofacies profiles reveal: (1) massive, matrix- and clast-supported gravel units (1--2 m thick) deposited by clast-poor and clast-rich debris flows respectively, with reworked; scoured tops overlain by thin (<0.25 m) trough cross-bedded gravel and ripple cross-laminated sand intervals, and (2) volumetrically less significant 1--2 m thick intervals comprising fining-upward sequences of interbedded cm-scale trough cross-bedded pebbly gravel, massive sand, horizontally stratified sand, and mud rock deposited by hyperconcentrated flow and stream flow during decelerating sheetflood events. Organic rich layers record periods of non-deposition. Channelized stream flow is restricted to minor reworking of in-channel debris flow and hyperconcentrated flow deposits.

Cechovic, M.T.; Schmitt, J.G. (Montana State Univ., Bozeman, MT (United States). Dept. of Earth Sciences)

1993-04-01

130

Experimental study of alluvial fans  

NASA Astrophysics Data System (ADS)

The role of geomorphic thresholds in the short term operation and long term evolution of alluvial fans was examined. A theoretical, cyclic pattern of alluvial fan evolution, involving apex sedimentation, followed by channel incision and a longer period of lateral channel migration and backfilling, was confirmed. The regularity and predictability of cyclic changes in spatial sedimentation patterns increased as mudflows became more important. When mudflows were the primary agent, apex slopes were steep and unstable under intervening streamflow conditions. It is suggested that the alluvial fans of an area will display a myriad of contrasting morphologic forms, even if they were not subject to a change in external conditions. Incongruous morphologic responses of fans in Idaho imply differing levels of landform stability existed at the last major change in conditions. Changes in external variables may affect the stability of alluvial fans by either physically altering the landform relative to an unchanging threshold value or by modifying the threshold value of one of the variables which controls fan response. Instead of controlling landform behavior, external stimuli act within the cyclic framework of landform development to merely hasten or delay the conclusion of one cycle and the initiation of the next.

Weaver, W. E.

131

Aridity Modulates N Availability in Arid and Semiarid Mediterranean Grasslands  

PubMed Central

While much is known about the factors that control each component of the terrestrial nitrogen (N) cycle, it is less clear how these factors affect total N availability, the sum of organic and inorganic forms potentially available to microorganisms and plants. This is particularly true for N-poor ecosystems such as drylands, which are highly sensitive to climate change and desertification processes that can lead to the loss of soil nutrients such as N. We evaluated how different climatic, abiotic, plant and nutrient related factors correlate with N availability in semiarid Stipa tenacissima grasslands along a broad aridity gradient from Spain to Tunisia. Aridity had the strongest relationship with N availability, suggesting the importance of abiotic controls on the N cycle in drylands. Aridity appeared to modulate the effects of pH, plant cover and organic C (OC) on N availability. Our results suggest that N transformation rates, which are largely driven by variations in soil moisture, are not the direct drivers of N availability in the studied grasslands. Rather, the strong relationship between aridity and N availability could be driven by indirect effects that operate over long time scales (decades to millennia), including both biotic (e.g. plant cover) and abiotic (e.g. soil OC and pH). If these factors are in fact more important than short-term effects of precipitation on N transformation rates, then we might expect to observe a lagged decrease in N availability in response to increasing aridity. Nevertheless, our results suggest that the increase in aridity predicted with ongoing climate change will reduce N availability in the Mediterranean basin, impacting plant nutrient uptake and net primary production in semiarid grasslands throughout this region.

Delgado-Baquerizo, Manuel; Maestre, Fernando T.; Gallardo, Antonio; Quero, Jose L.; Ochoa, Victoria; Garcia-Gomez, Miguel; Escolar, Cristina; Garcia-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Gozalo, Beatriz; Noumi, Zouhaier; Derak, Mchich; Wallenstein, Matthew D.

2013-01-01

132

Response of alluvial fan systems to the late Pleistocene to Holocene climatic transition: contrasts between the margins of pluvial Lakes Lahontan and Mojave, Nevada and California, USA  

Microsoft Academic Search

Dated shorelines of late Pleistocene pluvial Lakes Lahontan (Great Basin Desert, northwest Nevada) and Mojave (Mojave Desert, eastern California) provide timelines for the assessment of alluvial fan sedimentation at the lake margins during the late Pleistocene to early Holocene. Two sets of alluvial fan systems have been mapped: the Stillwater fans, feeding Lake Lahontan; and the Zzyzx fans, feeding Lake

Adrian M. Harvey; Peter E. Wigand; Stephen G. Wells

1999-01-01

133

Water sources accessed by arid zone riparian trees in highly saline environments, Australia  

Microsoft Academic Search

The flow regimes of arid zone rivers are often highly variable, and shallow groundwater in the alluvial aquifers can be very\\u000a saline, thus constraining the availability and quality of the major water sources available to riparian trees—soil water,\\u000a shallow groundwater and stream water. We have identified water sources and strategies used by riparian trees in more highly\\u000a saline and arid

Justin F. Costelloe; Emily Payne; Ian E. Woodrow; Elizabeth C. Irvine; Fred W. Leaney

2008-01-01

134

Fluoride hazard and assessment of groundwater quality in the semi-arid Upper Panda River basin, Sonbhadra district, Uttar Pradesh, India  

Microsoft Academic Search

Around 9000 inhabitants in the Panda River basin, Sonbhadhra District, Uttar Pradesh, India, are vulnerable to a “silent” dental and skeletal fluorosis from groundwater consumption. The fluoride source and seasonal groundwater quality variation were studied by collecting 65 groundwater samples in the Upper Panda River basin. Major rock types are phyllites and granite gneissic rocks. Fluoride concentrations are in the

N. Janardhana Raju; Sangita Dey; Wolfgang Gossel; Peter Wycisk

2012-01-01

135

Differential features of alluvial fans controlled by tectonic or eustatic accommodation space. Examples from the Betic Cordillera, Spain  

Microsoft Academic Search

The creation of accommodation space in subaerial sedimentary environments is closely linked to uplift the source area (along basin–margin faults) or to a rise in base level. Depending (amongst others) on the relative importance of these two factors, the margins of terrestrial sedimentary basins (where alluvial fans develop) produce aggradational, progradational or retrogradational stratigraphic architecture.We studied a total of 43

César Viseras; Mar??a L Calvache; Jesús M Soria; Juan Fernández

2003-01-01

136

Climatic controls on late Pleistocene alluvial fans, Cyprus  

NASA Astrophysics Data System (ADS)

Alluvial fans are commonly associated with tectonically active mountain ranges and tectonism is frequently held responsible for abrupt coarsening and cyclical sedimentation of alluvial fan sequences. Whilst it is accepted that tectonism provides the opportunity for alluvial fan development through the creation of topography, increasing gradients of fluvial systems supplying sediments, and creating accommodation for the storage of sediment flux, the role of climate in fan development is frequently neglected. The hypothesis that climatically controlled events can produce recognisable sedimentary signatures in alluvial fan deposits is tested in the active supra-subduction zone setting of the late Pleistocene of southern Cyprus. This study demonstrates through architectural analysis and the reconstruction of palaeoflood hydrology a recorded pattern of increasing and decreasing palaeoflow dynamics, with switches from a wetter to drier mode, clearly exhibited by changes in the sedimentology of the fan. At the present day Cyprus has a semi-arid climate and is influenced by a strongly seasonal rainfall pattern, largely restricted to the winter months (plus rare occurrences of summer cyclones). However at precession minima increased activity of western Mediterranean depressions produces wetter summers. Using inference we propose that longer-term increases in rainfall increased river discharge as recorded in the fan palaeoflood hydrology and occurred at minima in the precession. These periods correlate with the deposition of conglomeratic channels and open framework gravels. Drier periods are exhibited by sandier braided fluvial deposits. Shorter term or seasonal change is recorded in the form of 2nd and 3rd low order bounding surfaces. This increased activity of Mediterranean summer depressions increased precipitation to the wider Levantine area and was coincident with increased intensity of the north African and Indian Ocean (SW) monsoons. The resultant increase in river discharges at precession minima from both the Nile (and the wider Levant) resulted in the formation of sapropels in the eastern Mediterranean and is recorded as wet periods in speleothem deposits in the Soreq and Peqiin Caves of Israel. The predominant control of sedimentation on the late Pleistocene alluvial fans of southern Cyprus was climate.

Waters, J. V.; Jones, S. J.; Armstrong, H. A.

2010-03-01

137

Radiogenic 3He/4He Estimates and Their Effect on Calculating Plio-Pleistocene Cosmogenic 3He Ages of Alluvial-Fan Terraces in the Lower Colorado River Basin, USA  

NASA Astrophysics Data System (ADS)

Several alluvial-fan terraces near Topock, AZ were created by successive entrenchment of Pliocene and Pleistocene alluvial-fan gravels shed from the adjacent Black Mountains along the lower Colorado River corridor below Hoover Dam. These fans interfinger with and overlie main-stem Colorado River sands and gravels and grade to terrace levels that correspond with pre-existing elevations of the Colorado River. Absolute dates for the ages of Quaternary deposits on the lower Colorado River are rare and cosmogenic 3He age estimates of these surfaces would help constrain the timing of aggradation and incision in the lower Colorado River corridor. We analyzed individual basalt boulders from several terrace surfaces for total 3He/4He concentrations to calculate cosmogenic 3He ages of each fan terrace; 3He/4He values, expressed as R/Ra where Ra is the 3He/4He of air, range from 0.29 to 590. Black Mountain volcanic rocks have reported K-Ar ages between 15 and 30 Ma and basalt samples from adjacent alluvial fans contain 0.42 to 47× 1012 at/g of 4He, which has likely accumulated due to nuclear processes. The amount of radiogenic 3He/4He can be significant in old rocks with young exposure ages and can complicate determination of cosmogenic 3 He content. Alpha-decay of U, Th, and their daughter isotopes produces large amounts of 4He, whereas significant amounts of radiogenic 3He are only produced through the neutron bombardment of Li and subsequent beta-decay of tritium. We measured Li, U, Th, major and rare-earth element concentrations in whole-rock basalts and mineral separates. These concentrations are used to estimate the ratio of radiogenic helium contributed to the total helium system in our samples. Li concentrations typically range from 6 to 17 ppm, with one outlier of 62 ppm. U contents range from <0.1 to 2.7 ppm and Th contents range from 0.4 to 15.3 ppm. Based on these values, our calculations predict that the average radiogenic helium (R/Ra) contributed to the total helium in Black Mountain basalt samples is 0.011. Other noble gas studies have shown that radiogenic 3He/4He is independent of the U content, nearly independent of the Th content, and strongly influenced by the Li content of a rock; we find the same results. It is assumed that mantle gases are released when the sample is crushed into a fine powder before melting in a furnace under vacuum. To correct for the possible presence of mantle gases in our age-calculations, we crushed two samples under vacuum to measure the R/Ra value (7.9 and 16.03) of mantle helium trapped in fluid inclusions in olivines and pyroxenes. Based on our 3He corrections and calculations, boulders on these alluvial fans range in age from 10 ka to 2.7 Ma.

Fenton, C.; Pelletier, J.

2005-12-01

138

Geochemical signature and properties of sediment sources and alluvial sediments within the Lago Paranoá catchment, Brasilia DF: a study on anthropogenic introduced chemical elements in an urban river basin.  

PubMed

One of the largest urban agglomerations in Brazil is the capital Brasilia and its surrounding area. Due to fast urban sprawl and accelerated land use changes, available water supplies are near their limits. The water supply depends largely on surface water collected in reservoirs. There are increasing concerns regarding water shortages due to sediment aggradations, and of water quality due to geochemical modification of sediments from human activities. The concentration of 18 chemical elements and five sediment properties was analyzed from different potential land-based sediment sources and deposited alluvial sediment within the Lago Paranoà catchment. The goal of this study was to assess the distribution of chemical elements and geochemical/physical properties of potential sediment sources in the Lago Paranoá catchment. Principal component analysis and hierarchical cluster analysis were used to investigate the influence of different land use types on the geochemistry of sediments. Geochemical fingerprints of anthropogenic activities were developed based on the results of the cluster analysis grouping. The anthropogenic input of land use specific geochemical elements was examined and quantified by the calculation of enrichment factors using the local geological background as reference. Through comparison of the geochemical signature of potential sediment sources and alluvial sediments of the Lago Paranoá and sub-catchments, the relative contribution of land use specific sediment sources to the sediment deposition of the main water reservoir were estimated. The existing findings suggest a strong relationship between land use and quantifiable features of sediment geochemistry and indicate that urban land use had the greatest responsibility for recent silting in the Lago Paranoá. This assessment helps to characterize the role of human activities in mixed-used watersheds on sediment properties, and provides essential information to guide management responses towards more effective source-reduction strategies. PMID:23542435

Franz, C; Makeschin, F; Weiß, H; Lorz, C

2013-03-27

139

Groundwater vulnerability map for the Ebro alluvial aquifer between Jalón and Ginel tributaries (Spain)  

Microsoft Academic Search

The Quaternary deposits of the Ebro Basin in the surroundings of Zaragoza (Spain) form an unconfined alluvial aquifer with a high degree of permeability and low thickness of unsaturated materials. This fact causes a high degree of vulnerability to contamination, which implies consequences for land-use decisions and the risk management of existing industrial facilities. In addition, in the last decades

M. T. Lamelas; O. Marinoni; A. Hoppe; J. de La Riva

2007-01-01

140

Facies analysis of tertiary alluvial fan deposits in the Jundiaí region, São Paulo, southeastern Brazil  

Microsoft Academic Search

This article presents an analysis of facies of sedimentary sequences that occur as discontinuous bodies in the Jundiaí region, west of the main Tertiary continental basins of the southeastern Brazil continental rift. Nine identified sedimentary facies, grouped into four associations, suggest the existence of an ancient alluvial fan system whose source area was the Japi mountain range (Serra do Japi).

M. A. Neves; N. Morales; A. R. Saad

2005-01-01

141

INFLUENCE OF SEDIMENT SUPPLY, LITHOLOGY, AND WOOD DEBRIS ON THE DISTRIBUTION OF BEDROCK AND ALLUVIAL CHANNELS  

EPA Science Inventory

Field surveys in the Willapa River basin, Washington State, indicate that the drainage area?channel slope threshold describing the distribution of bedrock and alluvial channels is influenced by the underlying lithology and that local variations in sediment supply can overwhelm ba...

142

Holocene dust deposition rates in Australia’s Murray-Darling Basin record the interplay between aridity and the position of the mid-latitude westerlies  

NASA Astrophysics Data System (ADS)

Millennial scale variability in the strength/position of the mid-latitude westerlies, as interpreted from rates of dust deposition in an alpine mire south-eastern Australia, is demonstrated to be a major driver of climate variability during the mid to late Holocene. Dust deposition rates were calculated with a trace element provenance model. This approach is capable of distinguishing between sedimentation of local alluvium and genuine deposition of aeolian dust into the studied mire. Low dust deposition from 6500 to 5500 cal. BP occurred during a period of enhanced south-westerly winds which advected moisture into south-eastern Australia resulting in wet conditions. A subsequent dust pulse at 5500-4000 cal. BP is interpreted as a relaxation in south-westerlies resulting in a more arid phase and possibly enhanced climate variability. Reduced dust deposition between 4000 and 2000 cal. BP indicates a return to increased precipitation/moisture in the lower MDB associated with increased south-westerly geostrophic flow. The onset of more arid conditions after 2000 cal. BP implies a reduction in the frequency of precipitation bearing south-westerly winds. A final further significant finding from this study is the identification of a major dust deposition/wind erosion episode coinciding with the onset of European land clearing and agriculture in Australia.

Marx, Samuel K.; Kamber, Balz S.; McGowan, Hamish A.; Denholm, John

2011-11-01

143

Ground-Water Recharge in the Arid and Semiarid Southwestern United States  

USGS Publications Warehouse

Ground-water recharge in the arid and semiarid southwestern United States results from the complex interplay of climate, geology, and vegetation across widely ranging spatial and temporal scales. Present-day recharge tends to be narrowly focused in time and space. Widespread water-table declines accompanied agricultural development during the twentieth century, demonstrating that sustainable ground-water supplies are not guaranteed when part of the extracted resource represents paleorecharge. Climatic controls on ground-water recharge range from seasonal cycles of summer monsoonal and winter frontal storms to multimillennial cycles of glacial and interglacial periods. Precipitation patterns reflect global-scale interactions among the oceans, atmosphere, and continents. Large-scale climatic influences associated with El Ni?o and Pacific Decadal Oscillations strongly, but irregularly, control weather in the study area, so that year-to-year variations in precipitation and ground-water recharge are large and difficult to predict. Proxy data indicate geologically recent periods of naturally occurring multidecadal droughts unlike any in the modern instrumental record. Any anthropogenically induced climate change will likely reduce ground-water recharge through diminished snowpack at higher elevations. Future changes in El Ni?o and monsoonal patterns, both crucial to precipitation in the study area, are highly uncertain in current models. Current land-use modifications influence ground-water recharge through vegetation, irrigation, and impermeable area. High mountain ranges bounding the study area?the San Bernadino Mountains and Sierra Nevada to the west, and the Wasatch and southern Colorado Rocky Mountains to the east?provide external geologic controls on ground-water recharge. Internal geologic controls stem from tectonic processes that led to numerous, variably connected alluvial-filled basins, exposure of extensive Paleozoic aquifers in mountainous recharge areas, and distinct modes of recharge in the Colorado Plateau and Basin and Range subregions. The chapters in this professional paper present (first) an overview of climatic and hydrogeologic framework (chapter A), followed by a regional analysis of ground-water recharge across the entire study area (chapter B). These are followed by an overview of site-specific case studies representing different subareas of the geographically diverse arid and semiarid southwestern United States (chapter C); the case studies themselves follow in chapters D?K. The regional analysis includes detailed hydrologic modeling within the framework of a high-resolution geographic-information system (GIS). Results from the regional analysis are used to explore both the distribution of ground-water recharge for mean climatic conditions as well as the influence of two climatic patterns?the El Ni?o-Southern Oscillation and Pacific Decadal Oscillation?that impart a high degree of variability to the hydrologic cycle. Individual case studies employ a variety of geophysical and geochemical techniques to investigate recharge processes and relate the processes to local geologic and climatic conditions. All of the case studies made use of naturally occurring tracers to quantify recharge. Thermal and geophysical techniques that were developed in the course of the studies are presented in appendices. The quantification of ground-water recharge in arid settings is inherently difficult due to the generally low amount of recharge, its spatially and temporally spotty nature, and the absence of techniques for directly measuring fluxes entering the saturated zone from the unsaturated zone. Deep water tables in arid alluvial basins correspond to thick unsaturated zones that produce up to millennial time lags between changes in hydrologic conditions at the land surface and subsequent changes in recharge to underlying ground water. Recent advances in physical, chemical, isotopic, and modeling techniques have foster

Edited by Stonestrom, David A.; Constantz, Jim; Ferre, Ty P.A.; Leake, Stanley A.

2007-01-01

144

Reestablishing a Keystone Species in an Arid Coastal Environment: Saltbush (Salsola nollothensis) in Namibia  

Microsoft Academic Search

Beach hummocks are important ecological components of coastal ecosystems. Although hummocks are naturally adapted to harsh conditions, reestablishing them in arid areas poses great challenges. During a collaborative project, researchers from Namdeb Diamond Corporation and the Millennium Seed Bank Partnership investigated practical methods to reestablish saltbush (Salsola nollothensis) beach hummocks to restore areas disturbed by alluvial diamond mining. With focus

David Boyce; Herta Kolberg; Isabelle Brunner; Rosemary Newton; Antje Burke

2011-01-01

145

A Semiarid Long-Term Hydrologic Observatory at the Continental Scale: The Upper Río Grande Basin  

NASA Astrophysics Data System (ADS)

Water availability is critical in arid and semiarid regions, which comprise 35 percent of the land area of the globe. In the Southwestern US, climate variability and landscape heterogeneity lead to strong gradients in hydrological processes, which in turn impact land-atmosphere interactions, ecological dynamics, biogeochemical cycles and geomorphic change. This complexity presents a fundamental challenge to our understanding of hydrology, one that is best addressed through long-term, systematic field and remote-sensing observations and numerical-model investigations. In this poster, we will present our plans to study the interaction of climate-landscape-vegetation and water using a nested set of instrumented sites within the Upper Río Grande, a continental-scale semiarid watershed. This complex watershed extends from the snow-dominated headwater basins in San Juan Mountains of southern Colorado, through the Chihuahuan Desert in New Mexico, Texas and Mexico, to the desert valley alluvial basins southeast of El Paso, Texas. As part of the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) plan for a network of Long-Term Hydrologic Observatories (LTHOs), the Upper Río Grande would represent the combination of mountain landscapes, semiarid to arid alluvial basin aquifers and riparian corridors that are characteristic of the Western United States. We will describe existing hydrologic, ecologic and atmospheric measurement infrastructure in the watershed and discuss plans for integrating these into a coherent network that provides a core set of scientific data products for the hydrologic community. Data products generated by the Upper Río Grande LTHO will also aid in the testing of coupled numerical models of the atmosphere-surface-groundwater system applied at high resolution over the region. The Upper Río Grande presents unique opportunities to test hydrologic hypotheses concerning surface water-groundwater interactions and their control on runoff response, solute transport and reactivity, and riparian ecological communities

Hogan, J. F.; Vivoni, E. R.; Bowman, R. S.; Coonrod, J.; Thomson, B. M.; Samani, Z.; Ferre, P. T.; Phillips, F. M.; Rango, A.; Rasmussen, R.; Springer, E. P.; Small, E. E.

2004-12-01

146

Gravity and seismic reflection imaging of a deep aquifer in an arid region: Case history from the Jeffara basin, southeastern Tunisia  

NASA Astrophysics Data System (ADS)

A detailed mapping of the lateral and the vertical extension of the Upper Cretaceous units which contains aquifer bearing lithologies and may be part of the Complexe Terminal aquifer in the Jeffara basin of southeastern Tunisia using land and satellite Bouguer gravity anomaly data, eight seismic reflection profiles and two deep wells was performed. Borehole data indicated that the Upper Cretaceous unit is thickest within the Jeffara basin and thins considerably in the Dahar High. Bouguer gravity data in general confirms this result but lacks the resolution to accurately determine the thickness of the Upper Cretaceous units. Eight seismic reflection profiles constrained by borehole data indicated that the Upper Cretaceous aquifer may be present at depths greater than 500 m and is up to 400 m thick. The seismic reflection analysis showed that the Upper Cretaceous units contain two distinct zones. Within the northeastern portions of the Jeffara basin, the Upper Cretaceous units are influenced by horsts, grabens and tilted blocks where the Upper Cretaceous units are deeper and thicker units occur within the grabens. A second zone exits toward the basin's southwestern section where the Upper Cretaceous units are shallower and gradually thin against the Dahar High. Structural contour maps of the top and the base of the Upper Cretaceous aquifer constructed from the seismic reflection profiles reveal the presence of fractured depressions in the northeastern part of the Jeffara basin that are favourable to the hydrogeological exploitation.

Gabtni, Hakim; Alyahyaoui, Sofien; Jallouli, Chokri; Hasni, Walid; Mickus, Kevin Lee

2012-05-01

147

Nitrate in Arid Basin Groundwater: How Historical Trends in Water Quality, Pumping Practices, and Land Use Inform our Understanding of Flow in these Systems  

NASA Astrophysics Data System (ADS)

During the past 60 years, an overall increase in nitrate (NO3-) concentration has been observed in basinal groundwaters of the Trans-Pecos region of West Texas. In wells where data from multiple decades are available (n = 60), 75% had an increase in NO3- concentration of greater than 1mg/L that appears largely independent of changes in salinity; some wells experienced an increase in NO3- and TDS while others experienced an increase in NO3- with no change or a decrease in TDS. These changes in water quality are rapid in comparison to previously estimated rates of recharge to these basins (~10,000 yrs). We infer that changes in land use and pumping practices over the past 6 decades are partially responsible for the observed changes in water quality and water level in the basin aquifers. In the summer of 2011, we collected water quality information (including NO3 and TDS) from approximately 80 wells in five basins located in the Trans-Pecos Region of West Texas; Red Light Draw, Lobo and Ryan Flats, Eagle Flats, Wild Horse and Michigan Flats, and the Northern Salt Basin. We have combined these data with past water quality data, water level monitoring, pumping records, and historical land use data (including historical aerial photographs and historical land cover data sets) to examine how anthropogenic effects have altered recharge, flow systems, and water quality in these basins over the past 60 years. We observe that the largest historical users of water in the region have water with some of the highest NO3- concentrations and the largest increases in NO3- during the period of examination; this indicates a potential anthropogenic source for (at least some of) the NO3- in the basin aquifers. Water tables have rebounded and salinity has decreased in areas of some basins where irrigated agriculture has been curtailed, though the trends in NO3- concentrations are less clear. These observations point to flow systems that are more preferentially permeable and more complex than is reflected in current groundwater models.

Robertson, W. M.; Sharp, J. M., Jr.

2011-12-01

148

Using cosmogenic nuclides to contrast rates of erosion and sediment yield in a semi-arid, arroyo-dominated landscape, Rio Puerco Basin, New Mexico  

Microsoft Academic Search

Analysis of in-situ-produced 10 Be and 26 Al in 52 fluvial sediment samples shows that millennial- scale rates of erosion vary widely (7 to 366 m Ma ? ? ? ? ?1 ) through the lithologically and topo- graphically complex Rio Puerco Basin of northern New Mexico. Using isotopic analysis of both headwater and downstream samples, we determined that the

Paul R. Bierman; Joanna M. Reuter; Milan Pavich; Allen C. Gellis; Marc W. Caffee; Jennifer Larsen

2005-01-01

149

Observations on Alluvial Fans with Relevance to Recent Sediment Transport  

NASA Astrophysics Data System (ADS)

Steep (slope > 0.01) alluvial fans are widely written about, but there are almost no quantitative field studies of the fluvial channels moving water and sediment across them. For this reason, it is difficult to apply existing mechanistic models of fan evolution (e.g., Parker et al., 1998). It follows that we have little ability to quantitatively predict the effects of regional changes in water flux, sediment supply, or vegetation from ongoing anthropogenic and climatic changes on fans, particularly in arid lands. We have begun a field program to quantify fluvial sediment transport across alluvial fans by measuring the hydraulic geometry and bed texture of channels. The goal of the measurements is to parameterize sediment transport in a way that predicts the observed pattern of slope reduction, often from ~0.07 at fan heads to ~0.02 at downfan margins. In the Mojave Desert of California, we find that alluvial fan channel bankfull depths are largely 0.4-1.0 m at fan heads, decreasing to 0.1-0.2 m at distal fan margins. Contrary to many previous studies, we find that median gravel diameter does not change systematically along the upper 60-80% of active fan channels, and thus downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, surface sand cover increases systematically downfan from values of <20% above fan heads to distal fan values in excess of 70%. Plots of reach gradient versus sand content from these channels agree with experimental flume data from Ikeda and Iseya (1988) with similar hydraulic geometries, suggesting a general relation where similar loads can be transported at lower slopes because of the role that increased fines play in reducing the threshold for sediment transport. However, our attempts to model this role using reduced nondimensional critical shear stress values at higher sand concentrations (Wilcock & Crowe, 2003) with conventional excess shear stress sediment transport formulas result in underpredictions of the observed downfan slope decline. Although the relation between reach slope and sand cover suggests a strong role for sand cover in reducing fan slope, calculations indicate a strong component of bedload deposition is also necessary to match observed slope patterns. These uncertainties about the relative roles of sediment load and grainsize illustrate that much remains to be understood about alluvial fans before we can predict even first-order responses to climatic or anthropogenic change.

Stock, J. D.; Schmidt, K. M.; Miller, D. M.

2004-12-01

150

Mid late Holocene hydrological changes in the Mahi River, arid western India  

NASA Astrophysics Data System (ADS)

This paper attempts to quantify contemporary and palaeo-discharges and changes in the hydrologic regime through the mid late Holocene in the alluvial reach of the arid Mahi River basin in western India. The occurrence of terraces and pointbars high above active river levels and change in the width/depth ratio can be regarded as geomorphic responses to changes in discharge. Discharge estimates are made based on the channel dimensions and established empirical relations for the three types of channels: mid late Holocene, historic (the channel that deposited extensive pointbars above the present-day average flow level) and the present ones. The bankfull discharge of the mid late Holocene channel was ˜ 55 000 m3 s- 1 and that of the historic channel was ˜ 9500 m3 s- 1, some ˜ 25 times and ˜ 5 times greater than that of the present river (2000 m3 s- 1), respectively. Since the mid late Holocene, the channel form has changed from wide, large-amplitude meanders to smaller meanders, and decreases in the width/depth ratio, unit stream power and the bed shear stresses have occurred. It can be inferred that there has been a trend of decreasing precipitation since the mid late Holocene.

Sridhar, Alpa

2007-08-01

151

Modern and ancient alluvial fan deposits  

SciTech Connect

Understanding the structure and depositional processes of alluvial fans (river outwash deposits) has a special interest for those involved with the exploration of petroleum and many minerals. This collection of facsimile reprints of significant and classical research papers sheds new light on the subject. This reference covers the stratigraphy, sedimentology, and depositional processes of modern and ancient alluvial fans. Geographical areas considered include Arctic Canada, the American Southwest, Australia, Wyoming, Norway, and Spain. It includes a state-of-the-art introduction by the editor along with commentaries on all the papers included, a master author citation index and a subject index, and a chronological listing of early studies of alluvial fans.

Nilsen, T.H.

1985-01-01

152

Characterization of alluvial sources in the Owens Valley of eastern California using Fourier shape analysis  

SciTech Connect

Two-dimensional quartz grain shape was used to characterize sand grains from different source areas in the Owens Valley of eastern California. Combining a mathematical description of the grain outline and multivariate discriminant analysis, we have shown that quartz from clastic source rocks has a distinctive imprint when compared to samples from granitic, volcanic, or mixed fluvial source areas. Alternatively, quartz provided by a granitic source could equally well have been interpreted as if it were derived from any of the other sources considered. This study provides a standard of comparison for further analysis of sediment deposited in arid alluvial environments.

Wagoner, J.L.; Younker, J.L.

1982-03-01

153

Geoenvironmental and structural studies for developing new water resources in arid and semi-arid regions using remote sensing and GIS  

NASA Astrophysics Data System (ADS)

Water crises are rising with increasing world population and decreasing of freshwater resources. This problem is magnified in the arid and semi-arid regions because surface water resources are very limited and highly unreliable and therefore groundwater is the primary source of water supply in these regions. This study presents an integrated approach for the identification of groundwater occurrences using remote sensing, geological, and geophysical data, and establishing sustainable paths to groundwater management. The Central Eastern Desert (CED) of Egypt was selected as a test site for this study because its climate is arid and there is an urgent need to identify potential areas for groundwater accumulations. Field investigations indicated that the CED has three types of aquifers; shallow alluvial (SA), and fracture zone (FZ) aquifers in the valley depressions, and deep aquifers in the sedimentary succession that range in age from Late Cretaceous to Recent in the marginal extensional sub-basins (ESB) along the Red Sea coast. I developed three models: (1) a Geographic Information System (GIS) model for groundwater potential in the SA and FZ shallow aquifers; (2) a kinematic model for the development of the ESB; and (3) a groundwater budget model for the ESB aquifers. The GIS model is based on the analysis of remote sensing data of the Phased Array L-band Synthetic Aperture Radar, the Landsat Enhanced Thematic Mapper Plus, and the Advanced Spaceborne Thermal Emission and Reflection Radiometer digital elevation model. The model was evaluated and proven successful against the existing shallow water wells, and by geophysical surveys using Ground Penetrating Radar and Geoelectric methods. The kinematic model indicated that the ESB were formed in the orthogonal rifting phase in the late Oligocene that is followed by oblique rifting phase during the early Miocene which resulted to the en-echelon pattern of the inland ESB and nucleation of the rift depression into segments separated by oblique-slip accommodation zones. The groundwater budget model shows that the ESB aquifers have considerable amounts of paleowater that can be purified and used for drinking. The renewable groundwater of SA and FZ aquifers can be used for herding, irrigation, and ore dressing in the mining zones.

Amer, Reda Mohammed

154

Avulsion processes at the terminus of low-gradient semi-arid fluvial systems: Lessons from the Río Colorado, Altiplano endorheic basin, Bolivia  

NASA Astrophysics Data System (ADS)

The Río Colorado dryland river system in the southeast of the endorheic Altiplano Basin (Bolivia) terminates on a very flat coastal plain at the edge of the Salar de Uyuni, the world's largest salt pan with an area of ca. 12,500 km2. Since the Pleistocene the basin has experienced several lake expansion and contraction cycles in response to wetter and drier climate periods, respectively. At present the basin is in a dry climate period which results in a lake level lowstand and progradation of fluvial systems such as the Río Colorado onto the former lake bottom. The present field study of the terminus of the Río Colorado shows that the river experiences a gradual downstream decrease of bankfull width and depth. This bankfull decrease is caused by the combined effects of: (1) extremely low gradient of the lake bottom and, hence, loss of flow energy, and (2) downstream transmission losses due to high evaporation potential and river water percolation through the channel floor. Peak water discharge in seasonal, short-duration rain periods causes massive overbank flooding and floodplain inundation. On satellite images the morphology of the river terminus has a divergent pattern and resembles a network of coeval sinuous distributary channels. However, field observations show that only one channel is active at low flow stage, and at high-flow stage an abandoned, partially infilled channel may be active as well. The active channel at its termination splits into narrow and shallow anastomosing streams before its demise on the lacustrine coastal plain. The rest of the channels which form the divergent network are older sediment-filled abandoned sinuous river courses with multiple random avulsion points. These channel deposits, together with extensive amalgamated crevasse-splay deposits, form an intricate network of fluvial sand deposits. Successive stages of progressively deeper crevasse-channel incision into the floodplain are the result of waning-stage return flow of floodwaters towards the main channel. This results in increased crevasse-channel width, depth and length, and redeposition of eroded lacustrine coastal-plain sediment at the junction of the crevasse channel with the present-day river. A sedimentary model is proposed in which deep river bank incision by return flow in crevasse-channels creates the preferential locus for river avulsion. In a Lowstand Systems Tract with little vertical accommodation increase, the recurring avulsed-river paths result in a thin but laterally extensive network of amalgamated channel-fill, point-bar, crevasse-channel and crevasse-splay deposits. The resulting sedimentary architecture could easily be mistaken as produced by a distributary system of simultaneously active fluvial channels.

Donselaar, M. E.; Cuevas Gozalo, M. C.; Moyano, S.

2013-01-01

155

Dependable water supplies from valley alluvium in arid regions.  

PubMed

Reliable sources of high-quality water for domestic use are much needed in arid regions. Valley alluvium, coarse sand and gravel deposited by streams and rivers, provides an ideal storage medium for water in many regions of the world. However, river sediments will not accumulate in a valley without a natural or artificial barrier to slow the water. Sediments will deposit upstream of a barrier dam and form an alluvial deposit of relatively well-sorted material. The alluvium then acts as both an underground water-supply reservoir and a water filter, yielding a constant flow of high-quality water. Trap dams that store water in alluvial sediments and slowly release the filtered water represent an appropriate and inexpensive technology for combating desertification and mitigating the effects of drought at the community level. Small trap dams may be built as a community project using local materials and local labor. PMID:15641388

Van Haveren, Bruce P

2004-12-01

156

Hydrogeologic Behavior of an Alluvial Aquifer, Salta Province, Argentina: Simulations of Hydraulic Conductivity Field, Groundwater Flow, and Chloride Migration  

Microsoft Academic Search

This work was designed to analyze the hydrogeological behavior of an alluvial aquifer in the River Mojotoro basin site in the Province of Salta, Argentina. The study area presents coarse-grained sediments with high infiltration capacity. The hydraulic conductivity field is affected by the physical heterogeneity of the medium and a geostatistical method, kriging, was used to construct this field from

Jacqueline Köhn; Eduardo E. Kruse; Juan E. Santos

2002-01-01

157

Alluvial Fan in Icaria Planum, Mars: a MEX HRSC Study  

NASA Astrophysics Data System (ADS)

Numerous channels of the Claritas-Thaumasia area, such as Warrego Valles, indicate previous water flow activities. At some point, the wide basin (Raitala et al., 2005) of southern Claritas Fossae was filled by water transported from the uplands. After the paleolake reached the level of the lowest barrier valley floor it broke through this western saddle valley and formed a channel from the paleolake into the direction of Icaria Planum. The paleolake and adjoining formations were studied using the Mars Express HRSC data sets. Additional sapping channels connected into the channel from the direction of an old impact crater on the northern side of the saddle valley. In the west, close to Icaria Planum, the channel reached an impact crater and the water broke into it. This temporary crater lake has a delta at the channel mouth. The flow continued further through the western crater rim. The crater floor is lower than the channel neck out of the crater and indicates a paleolake phase. Water was led out from the impact crater into the lowlands of Icaria Planum where it formed an alluvial fan. The flow structures and the alluvial fan units in Icaria Planum are visible in the Mars Express HRSC color data. Reference: Raitala, J., Aittola, M., Korteniemi, J., Kostama, V.-P., Hauber, E., Kronberg, P., Neukum, G. and the HRSC Co-Investigator Team, 2005. Claritas paleolake studied from the MEX MEX HRSC data. LPS XXXVI, #1307.

Korteniemi, J.; Raitala, J.; Aittola, M.; Kostama, V.-P.; Hauber, E.; Kronberg, P.; Neukum, G.; HRSC Co-Investigator Team

2005-08-01

158

Geometry and evolution of a syntectonic alluvial fan, Southern Pyrenees  

SciTech Connect

Syntectonic alluvial fans formed on the northern margin of the Ebro Foreland Basin along the South Pyrenean thrust front during late orogenic thrust movements in the late Oligocene/early Miocene. The present-day geometry, structural relations and sedimentology of one of these fans, the Aguero fan in the province of Huesca, Spain, were studied. Field observations of the architecture of depositional facies and the geometries of syn-tectonic folds and unconformities indicate that the Aguero fan formed as the result of several phases of sedimentation which were primarily controlled by periods of tectonic activity and quiescence. The syntectonic unconformities and growth folds in the fan deposits provide a detailed record of the evolution of a fan adjacent to an active thrust front. Using a computer program to simulate sedimentation and deformation of an alluvial fan it is possible to constrain rates of both sedimentary and tectonic processes by modeling the evolution of the fan body. A facies model for the fan phases indicates that the facies change from proximal (coarse-grained, amalgamated) to distal (finger grained, stacked fining up cycles) in less than 1 km across a fan of radius estimated to be about 2 km.

Arminio, J.F. (Maraven S.A., Caracas (Venezuela)); Nichols, G.J. (Univ. of London, Egham, Surrey (United Kingdom))

1993-02-01

159

Improving assessment of groundwater-resource sustainability with deterministic modelling: a case study of the semi-arid Musi sub-basin, South India  

NASA Astrophysics Data System (ADS)

Since the 1990s, Indian farmers, supported by the government, have partially shifted from surface-water to groundwater irrigation in response to the uncertainty in surface-water availability. Water-management authorities only slowly began to consider sustainable use of groundwater resources as a prime concern. Now, a reliable integration of groundwater resources for water-allocation planning is needed to prevent aquifer overexploitation. Within the 11,000-km2 Musi River sub-basin (South India), human interventions have dramatically impacted the hard-rock aquifers, with a water-table drop of 0.18 m/a over the period 1989-2004. A fully distributed numerical groundwater model was successfully implemented at catchment scale. The model allowed two distinct conceptualizations of groundwater availability to be quantified: one that was linked to easily quantified fluxes, and one that was more expressive of long-term sustainability by taking account of all sources and sinks. Simulations showed that the latter implied 13 % less available groundwater for exploitation than did the former. In turn, this has major implications for the existing water-allocation modelling framework used to guide decision makers and water-resources managers worldwide.

Massuel, S.; George, B. A.; Venot, J.-P.; Bharati, L.; Acharya, S.

2013-08-01

160

Land Degradation in the Heihe River Basin in Relation to Plant Growth Conditions  

Microsoft Academic Search

Land degradation is a crucial issue in semi-arid and arid areas. The Heihe River basin is the second largest inland river basin in the arid regions of Northwest China. Land degradation is a serious passive problem for the socioeconomic development in this region. In this paper, we develop a land degradation model. Land Degradation Index (LDI), which integrates the main

Fengming Hui; Yongyuan Yin; Jiaoguo Qi; Peng Gong

2005-01-01

161

Groundwater vulnerability map for the Ebro alluvial aquifer between Jalón and Ginel tributaries (Spain)  

Microsoft Academic Search

The Quaternary deposits of the Ebro Basin in the surroundings of Zaragoza (Spain) form an unconfined alluvial aquifer with\\u000a a high degree of permeability and low thickness of unsaturated materials. This fact causes a high degree of vulnerability\\u000a to contamination, which implies consequences for land-use decisions and the risk management of existing industrial facilities.\\u000a In addition, in the last decades

M. T. Lamelas; O. Marinoni; A. Hoppe; J. de la Riva

2007-01-01

162

Early Devonian synorogenic alluvial-fan deposits of the Maccullochs Range, western New South Wales  

Microsoft Academic Search

The Early Devonian, Maccullochs Range beds (new) of the Winduck Interval largely comprise non-marine fine-grained sheet-flood-deposited sandstones which lie in the southeast sector of the Darling Basin Conjugate Fault System. Deposition of the >2.5 km-thick sequence occurred on the Wilcannia, Towers and Coolabah Bore alluvial fans, that were sourced largely from lightly indurated sandstone caps overlying a large basement high lying

G. Neef

2007-01-01

163

Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding  

Microsoft Academic Search

One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast\\u000a of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and\\u000a the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary

M. E. Young; R. G. M. de Bruijn; A. Salim Al-Ismaily

1998-01-01

164

Late Quaternary evolution of alluvial fans in the Playa, El Fresnal region, northern Chihuahua desert, Mexico: Palaeoclimatic implications  

Microsoft Academic Search

The Playa El Fresnal area is a tilted terrane characteristic of an extensional basin. It is a half graben\\/tilted-block system with a playa-lake on the basin floor flanked by piedmonts covered by alluvial fans. Structural heterogeneities within normal fault zones influenced the geomorphic expression of the uplifted footwall blocks of associated volcanism, and the downdropped hanging wall. The footwall area

J. Ortega-Ramírez; J. M. Maillol; W. Bandy; A. Valiente-Banuet; J. Urrutia Fucugauchi; J. Medina-Sánchez; G. J. Chacón-Cruz

2004-01-01

165

Impacts of hydroelectric dams on alluvial riparian plant communities in Eastern Brazilian Amazonian.  

PubMed

The major rivers of the Amazon River basin and their biota are threatened by the planned construction of large hydroelectric dams that are expected to have strong impacts on floodplain plant communities. The present study presents forest inventories from three floodplain sites colonized by alluvial riparian vegetation in the Tapajós, Xingu and Tocantins River basins in eastern Amazonian. Results indicate that tree species of the highly specialized alluvial riparian vegetation are clearly distinct among the three river basins, although they are not very distinct from each other and environmental constraints are very similar. With only 6 of 74 species occurring in all three inventories, most tree and shrub species are restricted to only one of the rivers, indicating a high degree of local distribution. Different species occupy similar environmental niches, making these fragile riparian formations highly valuable. Conservation plans must consider species complementarily when decisions are made on where to place floodplain forest conservation units to avoid the irreversible loss of unique alluvial riparian vegetation biodiversity. PMID:24068089

Ferreira, Leandro Valle; Cunha, Denise A; Chaves, Priscilla P; Matos, Darley C L; Parolin, Pia

2013-09-01

166

Facies architecture of basin-margin units in time and space: Lower to Middle Miocene Sivas Basin, Turkey  

NASA Astrophysics Data System (ADS)

The Miocene Sivas Basin is located within a collision zone, forming one of the largest basins in Central Turkey that developed unconformably on a foundered Paleozoic-Mesozoic basement and Eocene-Oligocene deposits. The time and space relationships of sedimentary environments and depositional evolution of Lower to Middle Miocene rocks exposed between Zara and Hafik towns is studied. A 4 km thick continuous section is subdivided into the Agilkaya and Egribucak Formations. Each formation shows an overall fining upward trend and contains three members. Although a complete section is present at the western part (near Hafik) of the basin, to the east the uppermost two members (near Zara) are absent. The lower members of both formations are composed of fluvial sheet-sandstone and red mudstone that migrate laterally on a flood basin within a semi-arid fan system. In the Agilkaya Formation that crops out near Zara, alluvial fans composed of red-pink volcanic pebbles are also present. The middle members are composed of bedded to massive gypsum and red-green mudstone of a coastal and/or continental sabkha environment. While the massive gypsum beds reach several 10’s of m in Hafik area, near Zara, they are only few m thick and alternate with green mudstones. In Hafik, bedded gypsums are intercalated with lagoonal dolomitic limestone and bituminous shale in the Agilkaya Formation and with fluvial red-pink sandstone-red mudstone in the Egribucak Formation. The upper members are made up of fossiliferous mudstone and discontinuous sandy limestone beds with gutter casts, HCS, and 3-D ripples. They indicate storm-induced sedimentation in a shallow marine setting. The disorganized accumulations of ostreid and cerithiid shells, interpreted as coquina bars, are the products of storm generated reworking processes in brackish environments. Rapid vertical and horizontal facies changes and the facies associations in both formations reflect the locally subsiding nature of this molassic basin.

Çiner, A.; Kosun, E.

2003-04-01

167

Erosion surfaces and Neogene landscape evolution in the NE Duero Basin (north-central Spain)  

NASA Astrophysics Data System (ADS)

We present a chronological model of erosion surface development in the Iberian and Cantabrian Ranges of north-central Spain. We map four erosion surfaces and interpret these to be related to Duero basin continental sediments and tectonic activity from Upper Oligocene to Plio-Pleistocene. The oldest erosion surface, SE1, formed across Upper Oligocene Lower Miocene synorogenic deposits; while surface SE2 was contemporaneous with the Middle Miocene alluvial systems, ending with an uplift stage in the Astaracian. The two most recent erosion surfaces, SE3 and SE4, developed during extensional tectonic episodes and are associated with the deposition of Upper Páramo sedimentary units at the end of the Miocene (Upper Turolian) and alluvial fan deposits, known as rañas (Plio-Pleistocene). With the exception of SE1, which seems to be associated with a relatively wet climate, the surfaces formed during periods of marked aridity and generally warm temperatures. Through geostatistical reconstruction of the best preserved surface (SE2), applying ordinary kriging method to the topography (DEM) of the erosion surface and its correlating sedimentary plains, we identify the deformation processes which occurred on this surface after its formation.

Benito-Calvo, Alfonso; Pérez-González, Alfredo

2007-08-01

168

Application of the groundwater-balance equation to indicate interbasin and vertical flow in two semi-arid drainage basins, Mexico  

NASA Astrophysics Data System (ADS)

An analysis of horizontal inflow and outflow in the groundwater-budget equation and the significance for interbasin flow are presented. Two field cases in Mexico, one in the Baja California peninsula and another in central Mexico, highlight the influence of interbasin flow. A significant proportion (approximately 70%) of the ed (thermal) groundwater probably originates outside the drainage basin. A conclusion is that a groundwater-balance study is an unsatisfactory method for determining some parameters, such as storativity (S). Specifically, the groundwater-balance approach provides unreliable results when vertical inflow is ignored or cannot be adequately defined. Vertical flow is indicated by the presence of groundwater temperatures as much as 23 °C higher than ambient temperature. Regional faults could be the pathways for upward flow. When vertical inflow is ignored, uncertainty in the estimation of the storativity through regional groundwater-balance calculation results. On the basis of the groundwater-balance equation, a value of S=0.19 appears to represent the confined condition of the developed part of the aquifer; this result is several orders of magnitude higher than would be reasonable according to the geological conditions. Findings are useful in evaluating whether a groundwater resource is being "overexploited". Conclusions are instructive in the application of transient-flow computer models, in which vertical flow of less dense water from beneath is not included. Résumé. L'article présente une analyse des entrées et des sorties horizontales dans l'équation du bilan d'une nappe et leur signification dans les écoulements entre bassins. Deux exemples provenant du Mexique, l'un dans la péninsule de Basse Californie, l'autre dans le centre du Mexique, mettent en lumière l'influence de l'écoulement entre bassins, où une proportion significative (environ 70%) de l'eau souterraine extraite, thermale, a probablement son origine hors du bassin. Une conclusion est qu'une étude par bilan de la nappe est une méthode qui n'est pas satisfaisante pour déterminer certains paramètres comme le coefficient d'emmagasinement. En particulier, l'approche par le bilan de la nappe donne des résultats qui ne sont pas fiables lorsque l'on ignore la drainance verticale ou que l'on ne peut pas la définir correctement. L'existence d'une drainance verticale est prouvée par des températures de l'eau souterraine pouvant être supérieures de 23 °C à la température ambiante. Des failles régionales peuvent permettre ces écoulements vers le haut. Lorsque l'on ignore la drainance verticale, on introduit une incertitude sur l'estimation de l'emmagasinement à partir des calculs du bilan régional de la nappe. Sur la base de l'équation du bilan de la nappe, une valeur de S=0,19 semble représenter les conditions captives de la partie développée de l'aquifère ce résultat est plus élevé, de plusieurs ordres de grandeur, que celui que l'on peut raisonnablement attendre des conditions géologiques. Ces résultats sont utiles pour évaluer si une ressource en eau souterraine est "surexploitée". Ces conclusions sont intéressantes lorsque l'on applique des modèles d'écoulement transitoire dans lesquels on ne prend pas en compte la drainance verticale d'une eau plus légère remontant. Resumen. En este trabajo, se investigan las entradas y salidas de flujo horizontal en la ecuación de balance de agua subterránea, así como el papel que desempeñan en el flujo entre cuencas. Se analizan dos ejemplos de México, uno en la Península de Baja California y otro en la parte central del país. En ambos, destaca la influencia del flujo entre cuencas, ya que se estima que una parte importante (aproximadamente el 70%) del agua termal extraída procede de una cuenca superficial externa. Se concluye que el método basado en cálculos de balance de agua subterránea no es satisfactorio para determinar algunos parámetros, como, por ejemplo, el coeficiente de almacenamiento (S). En particular, la ecuación de ba

Carrillo-Rivera, J. J.

2000-09-01

169

Riparian ecosytems of semi-arid North America: Diversity and human impacts  

Microsoft Academic Search

Riparian ecosystems in the semi-arid West of North America are diverse but have many similarities. The mountainous landscape\\u000a with wide range of latitude, longitude, and elevation offers diverse opportunities for streamside vegetation. All riparian\\u000a ecosystems in the region are dependent on supplemental water, usually from the shallow, valley alluvial aquifer. Western riparian\\u000a ecosystems provide several ecological services. They stabilize streambanks,

Duncan T. Patten

1998-01-01

170

The paradox of large alluvial rivers (Invited)  

NASA Astrophysics Data System (ADS)

Large alluvial rivers exhibit large floodplains, very gentle slopes, a good selection of bed materials (generally sand), low specific stream power, and could represent the ultimate examples of “dynamic equilibrium” in fluvial systems. However, equilibrium can be discussed at different temporal scales. Base level changes by tectonic or climatic effects, modifications in sediment and water supply or different kinds of human impacts are the traditional causes that could trigger “disequilibrium” and changes in the longitudinal profile. Simultaneously, adjustments of longitudinal profiles were thought to be evolving from downstream to upstream by several processes, being the most common receding erosion. Some authors,have demonstrated that when changes in base level happen, a variety of adjustments can be reached in the lower course in function of the available sediment and water discharge, slopes articulations between the fluvial reach and the continental shelve, among others, and that the adjustments can be transferred upstream significantly in small rivers but not far upstream along large fluvial systems. When analyzing the Quaternary fluvial belts of large rivers in the millennium scale, paleohydrological changes and modifications in floodplain constructional processes or erosion, are associated normally to late Quaternary climatic changes. The study of several of the largest rivers demonstrates that climatic changes and fluvial responses are not always working totally in phase and those direct cause-consequences relations are not a rule. This paper describes floodplain evolution and the lagged geomorphic responses of some large river system to recent climatic changes. Information from some of the largest rivers of the world such as the Amazon, Parana, several tributaries of the Amazon (Negro, Xingú, Tapajos) as well as some large Siberian Rivers was used. Since the last deglaciation, these large fluvial systems have not had enough time to reach equilibrium conditions along whole the river and present several stages of “incomplete floodplains”. Furthermore, minor climatic changes during the Holocene have possibly also affected their fluvial style, producing additional and partial adjustments. A main concept presented here is that large rivers achieved equilibrium conditions mainly from upstream to downstream by partially filling up their valleys and local sedimentary basins/sediment sinks (e.g. wide valleys, flood basins and permanent water saturated floodplains, tectonic sunken blocks, among others) with a variety of morpho-sedimentological processes, and transferring equilibrium conditions from upstream to downstream. When the “available space” (sedimentary sink) becomes as full of sediments as possible, the rivers adjust on a more efficient corridor of channels in quasi-equilibrium conditions. Valley infilling processes progress downstream as a prograding system on areas of the channel-floodplain system that have not yet reached quasi-equilibrium conditions Because most results in the literature are focused on small to medium size rivers, these results intend to open a new discussion about floodplain mechanisms of construction, demystifying some traditional concepts relating floodplains and equilibrium, and climatic changes and river responses in large rivers.

Latrubesse, E. M.

2010-12-01

171

Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front  

USGS Publications Warehouse

Controversy exists over whether alluvial-fan sedimentation along tectonically active mountain fronts is driven by climatic changes or tectonics. Knowing the age of sedimentation is the key to understanding the relationship between sedimentation and its cause. Alluvial-fan deposits in Death Valley and throughout the arid southwestern United States have long been the subjects of study, but their ages have generally eluded researchers until recently. Most mapping efforts have recognized at least four major relative-age groupings (Q1 (oldest), Q2, Q3, and Q4 (youngest)), using observed changes in surface soils and morphology, relation to the drainage net, and development of desert pavement. Obtaining numerical age determinations for these morphologic stages has proven challenging. We report the first optically stimulated luminescence (OSL) ages for three of these four stages deposited within alluvial-fans along the tectonically active Black Mountains of Death Valley. Deposits showing distinct, remnant bar and swale topography (Q3b) have OSL ages from 7 to 4 ka., whereas those with moderate to poorly developed desert pavement and located farther above the active channel (Q3a) have OSL ages from 17 to 11 ka. Geomorphically older deposits with well-developed desert pavement (Q2d) have OSL ages ???25 ka. Using this OSL-based chronology, we note that alluvial-fan deposition along this tectonically active mountain front corresponds to both wet-to-dry and dry-to-wet climate changes recorded globally and regionally. These findings underscore the influence of climate change on alluvial fan deposition in arid and semi-arid regions. ?? 2007 Elsevier Ltd and INQUA.

Sohn, M. F.; Mahan, S. A.; Knott, J. R.; Bowman, D. D.

2007-01-01

172

Anabranching in mixed bedrock-alluvial rivers: the example of the Orange River above Augrabies Falls, Northern Cape Province, South Africa  

Microsoft Academic Search

Anabranching is characteristic of a number of rivers in diverse environmental settings worldwide, but has only infrequently been described from bedrock-influenced rivers. A prime example of a mixed bedrock-alluvial anabranching river is provided by a ?150-km long reach of the Orange River above Augrabies Falls, Northern Cape Province, South Africa. Here, the perennial Orange flows through arid terrain consisting mainly

S. Tooth; T. S McCarthy

2004-01-01

173

Design of canals in alluvial soils  

Microsoft Academic Search

Conclusions 1.The morphometric method of estimating the geometry of stable canal channels, as based on a deeper physical nature and using the fluvial process theory principle, has become most popular in solving the problem of designing canals in alluvial soil. It can be considered that sufficiently reliable relations have presently been obtained which can be used in practice with consideration

E. K. Rabkova

1991-01-01

174

Appraisal of Nuclear Waste Isolation in the Vadose Zone in Arid and Semi-Arid Regions: Emphasis on the Nevada Test Site.  

National Technical Information Service (NTIS)

An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population de...

H. A. Wollenberg J. S. Y. Wang G. Korbin

1983-01-01

175

Fluvial and lacustrine facies in the middle to late Devonian Pertnjara Group, Amadeus Basin, Northern Territory, and their relationship to tectonic events and climate  

NASA Astrophysics Data System (ADS)

The distribution, grainsize and facies variations in the Middle to Late Devonian Pertnjara Group, Amadeus Basin, can be directly related to tectonic events which formed and deformed the basin during sedimentation. The Pertnjara Group consists of a series of lacustrine, braided and meandering fluviatile and alluvial fan deposits which accumulated as a southward thinning wedge in the Amadeus Basin during successive pulses of the Alice Springs Orogeny. Sedimentation of the group started during a pluvial quiescent period following the Late Ordovician Rodingan Movement and deposition of the aeolian Mereenie Sandstone. An uplift event (Pertnjara Movement) in the late Givetian or early Frasnian produced the first wedge of fluviatile sandstone which accumulated in the rapidly subsiding north-central Amadeus Basin (Carmichael Sub-basin). At the same time, thinner sequences of fluvial and aeolian sandstone were accumulating in the eastern part of the Amadeus Basin. The following quiescent phase was characterized by the deposition of playa-lake siltstone in the center of the Amadeus Basin under semi-arid or arid conditions. Gentle uplift north of the basin during the Frasnian Henbury Movement resulted in widespreas deposition of the fluviatile, lower Hermannsburg Sandstone. The rate of uplift increased rapidly during the succeeding late Frasnian to early Famennian Brewer Movement and was probably concentrated along the Redbank Deformed Zone close to the present northern margin of the basin. A thick wedge of Brewer Conglomerate accumulated contemporaneously in the rapidly downwarping Missionary Plain Trough and Carmichael Sub-basin and records a return to plubial conditions with abundant organic matter being preserved. Growth structures within the basin record movement during some of these tectonic events and help to define the areas affected at each stage. Rank studies on organic material confirm the sedimentological data and also indicate that at least 1 to 2 km of younger strata must have been removed from the northern part of the basin. These deposits probably reflect the Carboniferous and possibly Early Permian uplift events in the Arunta Block indicated by radiometric and fission track studies. The main folding of the Pertnjara sequence occurred during one of these later pulses of the Alice Springs Orogeny.

Jones, B. G.

176

Spatiotemporal trends of aridity index in arid and semi-arid regions of Iran  

NASA Astrophysics Data System (ADS)

The spatiotemporal trends of aridity index in the arid and semi-arid regions of Iran in 1966-2005 were investigated using the Mann-Kendall test and Theil-Sen's slope estimator. The results of the analysis showed negative trends in annual aridity index at 55 % of the stations, while just one site had a statistically significant ( ? = 0.1) negative trend. Furthermore, the positive trends in the annual aridity index series were significant at the 95 % confidence level at Bushehr and Isfahan stations. The significant negative trend in the annual aridity index was obtained over Mashhad at the rate of -0.004. In the seasonal series, the negative trends in the spring and winter aridity index were larger compared with those in the other seasonal series. A noticeable decrease in the winter aridity index series was observed mostly in the southeast of the study area. In the summer and autumn aridity index, two significant positive trends were found.

Shifteh Some'e, B.; Ezani, Azadeh; Tabari, Hossein

2013-01-01

177

Dissolution et precipitation des carbonates dans des Sols (Calcrètes) en zone aride, bassin de Ksabi, moyenne moulouya, maroc: Consequence sur la desertification  

Microsoft Academic Search

Dissolution and Precipitation of Carbonates in Arid Soils (Calcretes), Ksabi Basin, Morocco; Consequences on the Desertification.In an arid region of North?Eastern Morocco (Ksabi basin, central Moulouya), formation and conditions of carbonate accumulation in coarse alluvium were studied. All levels of pleistocene terraces were affected by those accumulations, among them the ones of pedological origin (calcretes) were caracterized. Three categories were

M. Kaemmerer; J. C. Revel; J. Berrier; A. Braund; D. Lefevre

1991-01-01

178

Simplified process modeling of river avulsion and alluvial architecture: Connecting models and field data  

NASA Astrophysics Data System (ADS)

Modeling is an invaluable tool for studying sedimentary basin filling and for understanding depositional processes with long recurrence intervals, including channel avulsion. Simplified modeling approaches, such as cellular models and process-analogue experiments, are particularly useful for efficiently exploring alternative hypotheses and evaluating first-order controls on river avulsion and alluvial architecture. Here we review the history and current state of the art in simplified avulsion and alluvial architecture models, with a particular focus on how results and insights from these models can be incorporated into field and subsurface studies, and vice versa. Simplified avulsion and alluvial architecture models have proliferated in the past decade, providing a wide variety of models to serve as a basis for future coupled field-modeling studies. We compare features of leading models and discuss avenues for effectively pairing model capabilities with hypotheses and field data. Outstanding questions highlighted by recent modeling efforts include 1) What thresholds control avulsion initiation in different systems? 2) How do floodplain processes and topography influence avulsion dynamics and alluvial architecture? 3) What factors determine where avulsion channels stabilize? Answering these questions will require targeted modeling efforts coupled to data from ancient systems. Hence our model comparison emphasizes features that can be used to choose or design fit-for-purpose models, and we outline how quantitative data useful for model selection and validation can be obtained from modern systems and ancient deposits. Matching model goals with targeted questions, and model parameters and predictions with quantitative field data, will help tighten communication between field- and model-oriented sedimentary geologists, facilitating advances in our understanding of river avulsion and alluvial architecture.

Hajek, Elizabeth A.; Wolinsky, Matthew A.

2012-06-01

179

Channel form and processes in bedrock and alluvial reaches of the Raritan River, New Jersey  

NASA Astrophysics Data System (ADS)

Fluvial geomorphologists have generally considered alluvial and bedrock channels to be fundamentally different in character, alluvial channels being shaped by sediment-transport processes and bedrock channels being shaped by structural and lithologic controls. This study examines a 12-km bedrock-floored reach of the Raritan River that separates two gravel-bed reaches, above and below. The bedrock channel has a patchy veneer of sandy gravel that covers the bed in areas of low slope but elsewhere consists of lateral bars and discrete, two-dimensional gravel bed forms perched on bedrock. Mean B-axes of the 25 largest clasts on the crests of these bed forms range from 10.4 to 13.8 cm. Shear stresses estimated from measured velocity profiles and depth-slope calculations indicate that most clasts on the bed forms are entrained by the bankfull discharge (290 m/s) which is equaled or exceeded about 1%of the time. The thalweg of the 80-m-wide channel is incised about 0.5 to 0.7 m, and it meanders with a wavelength of about 750 m, or approximately 10 times channel width. This thalweg meander wavelength is consistent with reference to drainage area when compared to channel meander wavelengths in other locations within the basin and is similar to that in other rivers of comparable dimensions and discharge. The bedrock-alluvial reach is similar to alluvial channels with reference to meander geometry and sediment distribution. It occupies an intermediate position on a continuum of channels-of varying sediment supply in relation to transport capacity, ranging from alluvial channels to those completely formed in bedrock.

Ashley, Gail M.; Renwick, William H.; Haag, Gary H.

1988-05-01

180

Experimental Drainage Basins in Israel  

Microsoft Academic Search

Within the hyper-arid to semiarid areas of Israel are three experimental drainage basins. They are the Nahal (stream in Hebrew) Yael, subdivided into five sub-basins, Rahaf-Qanna'im (main and tributary, respectively) and Eshtemoa. These basins vary in drainage area and climate, and in monitoring duration and type. All are drained by gravel-bed channels. As the size of monitored drainage area is

J. B. Laronne; J. Lekach; H. Cohen; J. Gray

2002-01-01

181

Sedimentary facies and depositional environments of early Mesozoic Newark Supergroup basins, eastern North America  

USGS Publications Warehouse

The early Mesozoic Newark Supergroup consists of continental sedimentary rocks and basalt flows that occupy a NE-trending belt of elongate basins exposed in eastern North America. The basins were filled over a period of 30-40 m.y. spanning the Late Triassic to Early Jurassic, prior to the opening of the north Atlantic Ocean. The sedimentary rocks are here divided into four principal lithofacies. The alluvial-fan facies includes deposits dominated by: (1) debris flows; (2) shallow braided streams; (3) deeper braided streams (with trough crossbeds); or (4) intense bioturbation or hyperconcentrated flows (tabular, unstratified muddy sandstone). The fluvial facies include deposits of: (1) shallow, ephemeral braided streams; (2) deeper, flashflooding, braided streams (with poor sorting and crossbeds); (3) perennial braided rivers; (4) meandering rivers; (5) meandering streams (with high suspended loads); (6) overbank areas or local flood-plain lakes; or (7) local streams and/or colluvium. The lacustrine facies includes deposits of: (1) deep perennial lakes; (2) shallow perennial lakes; (3) shallow ephemeral lakes; (4) playa dry mudflats; (5) salt-encrusted saline mudflats; or (6) vegetated mudflats. The lake margin clastic facies includes deposits of: (1) birdfoot deltas; (2) stacked Gilbert-type deltas; (3) sheet deltas; (4) wave-reworked alluvial fans; or (5) wave-sorted sand sheets. Coal deposits are present in the lake margin clastic and the lacustrine facies of Carnian age (Late Triassic) only in basins of south-central Virginia and North and South Carolina. Eolian deposits are known only from the basins in Nova Scotia and Connecticut. Evaporites (and their pseudomorphs) occur mainly in the northern basins as deposits of saline soils and less commonly of saline lakes, and some evaporite and alkaline minerals present in the Mesozoic rocks may be a result of later diagenesis. These relationships suggest climatic variations across paleolatitudes, more humid to the south where coal beds are preserved, and more arid in the north where evaporites and eolian deposits are common. Fluctuations in paleoclimate that caused lake levels to rise and fall in hydrologically closed basins are preserved as lacustrine cycles of various scales, including major shifts in the Late Triassic from a wet Carnian to an arid Norian. In contrast, fluvial deposits were mainly formed in response to the tectonic evolution of the basins, but to some extent also reflect climatic changes. The Newark Supergroup illustrates the complexity of rift-basin sedimentation and the problems that may arise from using a single modern analog for sedimentary deposition spanning millions of years. It also shows that a tremendous wealth of depositional, climatic, and tectonic information is preserved in ancient rift-basin deposits which can be recovered if the depositional processes of modern rift-basin deposits are understood. ?? 1991.

Smoot, J. P.

1991-01-01

182

Can complementary methods reliably estimate evapotranspiration in semi-arid regions?  

Microsoft Academic Search

In semi-arid regions, the largest portion of rainfall is lost as evapotranspiration (ET). Therefore, the uncertainty in estimating ET can lead to the inaccurate prediction of water balance and water resources needs. Furthermore, rural river basins are characterized by scarcity of data and resources, adding additional challenges in estimating water resources needs in the basin. This research aims at estimating

F. M. Anayah; J. J. Kaluarachchi

2010-01-01

183

UNESCO's G-WADI Program - Developing and Delivering Tools for Improved Water Management in Semi-arid and Arid Lands  

NASA Astrophysics Data System (ADS)

UNESCO's Water and Development Information for Arid Lands - A Global Network (G-WADI) aims to strengthen the capacity to manage the water resources of arid and semi-arid areas around the globe through a network of international and regional cooperation. Six centers, including SAHRA headquartered at the University of Arizona and CHRS at UC-Irvine, are cooperating to improve water resource management by sharing knowledge and tools. Specific objectives include: improved understanding of the special characteristics of hydrological systems and water management needs in arid areas, through shared data and experiences; capacity building of individuals and institutions; raising awareness of advanced technologies for data provision, data assimilation, and system analysis; and promoting integrated basin management and the use of appropriate decision support tools. SAHRA coordinates G-WADI's information dissemination via G-WADI's web site and publications. Web-based resources include Global Water News Watch and the subscription service, Water News Tracker, plus access to remotely sensed precipitation data from HyDIS. Information on use of isotopes and chemical tracers is also featured. Materials and outcomes from various workshops and short courses on modeling, water harvesting, and impacts of climate change also are provided. While the intent is to benefit water resource managers in semi- arid and arid developing countries, the collaboration among international water centers, and perspectives and traditional knowledge gained from users, has benefitted U.S. researchers in many ways.

Woodard, G. C.; Imam, B.; Sorooshian, S.

2007-12-01

184

Short-term sediment accumulation rates determined from Eocene alluvial paleosols  

NASA Astrophysics Data System (ADS)

A new method uses alluvial paleosols to calculate sediment accumulation rates for thin (25 m) stratigraphic intervals and allows the reliable interpolation of ages for stratigraphic levels within a thick stratigraphic interval bounded by established dates. Sediment accumulation rates calculated for a 650 m composite section in the Eocene Willwood Formation of Wyoming span time intervals ranging from only 0.05 to 0.25 m.y. Important sedimentologic changes coincide with changes in accumulation rate and indicate close and direct relations between the history of basin subsidence and depositional patterns.

Kraus, Mary J.; Bown, Thomas M.

1993-08-01

185

Late Quaternary eolian and alluvial response to paleoclimate, Canyonlands, southeastern Utah  

USGS Publications Warehouse

In upland areas of Canyonlands National Park, Utah, thin deposits and paleosols show late Quaternary episodes of eolian sedimentation, pedogenesis, and climate change. Interpretation of the stratigraphy and optically stimulated luminescence ages of eolian and nearby alluvial deposits, their pollen, and intercalated paleosols yields the following history: (1) Eolian deposition at ca. 46 ka, followed by several episodes of alluviation from some time before ca. 40 ka until after 16 ka (calibrated). (2) Eolian deposition from ca. 17 ka to 12 ka, interrupted by periods of pedogenesis, coinciding with late Pleistocene alluviation as local climate became warmer and wetter. (3) A wetter period from 12 to 8.5 ka corresponding to the peak of summer monsoon influence, during which soils formed relatively quickly by infiltration of eolian silt and clay, and trees and grasses were more abundant. (4) A drier period between ca. 8.5 and 6 ka during which sheetwash deposits accumulated and more desertlike vegetation was dominant; some dunes were reactivated at ca. 8 ka. (5) Episodic eolian and fluvial deposition during a wetter, cooler period that began at ca. 6 ka and ended by ca. 3-2 ka, followed by a shift to drier modern conditions; localized mobilization of dune sand has persisted to the present. These interpretations are similar to those of studies at the Chaco dune field, New Mexico, and the Tusayan dune field, Arizona, and are consistent with paleoclimate interpretations of pollen and packrat middens in the region. A period of rapid deposition and infiltration of eolian dust derived from distant igneous source terranes occurred between ca. 12 and 8 ka. Before ca. 17 ka, and apparently back to at least 45 ka, paleosols contain little or no such infiltrated dust. After ca. 8 ka, either the supply of dust was reduced or the more arid climate inhibited translocation of dust into the soils. ?? 2005 Geological Society of America.

Reheis, M. C.; Reynolds, R. L.; Goldstein, H.; Roberts, H. M.; Yount, J. C.; Axford, Y.; Cummings, L. S.; Shearin, N.

2005-01-01

186

High resolution sequence stratigraphy and reservoir architecture of proximal alluvial deposits: The Buntsandstein facies of central Spain  

SciTech Connect

The Buntsandstein facies outcrops along a 12 km long, 150 m thick cuesta near Ayllon (Central Spain). The outcrop study is based on vertical sedimentological sections and continuous photo paneling, and demonstrates the presence of two depositional systems: an alluvial fan system in the lower half of the outcrop, and a straight and braided river system in the upper part of the outcrop. This overall evolution is probably related to base-level fall to base-level rise cycle, in which the reservoir architecture is linked to genetic units stacking pattern: during the base-level fall, the alluvial fan is prograding over sand flat and sandy alluvial plain deposits. Coarse and pebbly proximal sandsheets are interbedded with finer reddish distal deposits. Reservoirs units are laterally continuous, but silty alluvial plain deposits constitute vertical permeability barriers, during base-level stillstand, erosive channels and sandsheets are vertically amalgamated. Reservoirs units are laterally continuous and vertically connected, during the base-level rise, alluvial fan deposits are overlapped by straight river deposits. Reservoirs units are laterally connected but silty argillaceous alluvial plain horizons are preserved, at the end of the base-level rise, braided and straight river deposits are amalgamated. Fully connected, these reservoirs units have a very large lateral extension. A lithofacies database is compiled on this outcrop, and variograms, horizontal and vertical proportion curves are completed. Each stage of the base-level cycle is then quantitatively characterized by a specific heterogeneity pattern. The outcrop study will improve the prediction of reservoir extension and architecture in subsurface gas storage of the Paris basin.

Oliver, L.; Desaubliaux, G. [Institut Francais du Petrole, Rueil-Malmaison (France); Verdier, F. [Gaz de France, Denis (France)] [and others

1995-08-01

187

Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)  

SciTech Connect

An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100{sup 0}C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites.

Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

1983-05-01

188

Joint clay-heavy-light mineral analysis: a tool to investigate the hydrographic-hydraulic regime of Late Cenozoic deltaic inland fans under changing climatic conditions (Cuvelai-Etosha Basin, Namibia)  

NASA Astrophysics Data System (ADS)

An interdisciplinary study (major and minor elements, C and O isotopes, heavy and light minerals, phyllosilicates, wireline logs) in northern Namibia unraveled the hydrographic and hydraulic evolution of alluvial-fluvial sediments of the Kunene and Cubango megafans (Etosha-Cuvelai Basin). Three principal aquatic regimes were operative within the megafan complex: (1) the hydrographic regime, (2) the proximal hydraulic regime, (3) the distal hydraulic regime. The allogenic mineral assemblages mirror the hydrographic variation or drainage system and the lithological evolution of the fan sediments (alluvial-fluvial fan, lacustrine environment with evaporites, fan delta progradation). Authigenic heavy minerals are markers of the physical-chemical condition (Eh and pH values) of the hydraulic regime within the proximal fan at the basin margin. Authigenic heavy, light and clay minerals equally contribute to the determination of the fluid chemistry and temperature, as well as the source of chemical constituents of the former pore fluids percolating through the distal fan. Carbonatization was the most pronounced event in the distal hydraulic system and controlled by the presence of biogenic as well as atmospheric carbon. The isotope-based determination of the temperatures, albeit strongly fluctuating, do not exceed 40 °C. The overall pH values determined for the hydraulic regime within the distal fan range from slightly acidic to alkaline. The presence of zeolites attests to some short-lasting but strong deviations from the pH range, mainly towards more alkaline conditions. Heavy, light and clay mineral analyses proved to be a useful tool to determine the (paleo)hydrology of alluvial-fluvial fan systems in tropical arid to semiarid climates.

Dill, Harald G.; Kaufhold, S.; Lindenmaier, F.; Dohrmann, R.; Ludwig, R.; Botz, R.

2013-01-01

189

Turkana Grits - a Cretaceous braided alluvial system in northern Kenya  

SciTech Connect

Rather spotty but excellent exposures of the Cretaceous-age Turkana Grits occur near the western shore of Lake Turkana, northern Kenya. These very coarse to pebbly arkosic sandstones and sandy conglomerates were derived from and rest unconformably upon Precambrian metamorphic basement; they are overlain by late Tertiary basaltic flows that comprise much of the volcanics in the East African Rift Zone. The formation ranges up to 2000 ft thick in the Laburr Range. Several outcrops contain sauropod, crocodile, and tortoise remains as well as abundant trunks of petrified wood (Dryoxylon). Five major facies make up the Turkana Grits and record a major episode of continental fluvial deposition in basins flanked by Precambrian basement. Facies 1 is crudely stratified, cobble and boulder conglomerate (clast-supported); Facies 2 is crudely stratified pebble-cobble conglomerate and pebbly sandstone; Facies 3 is trough cross-bedded, very coarse sandstones containing fossils wood and vertebrate remains; Facies 4 is crudely stratified to massive sandstones with ironstone nodules; and Facies 5 is red, purple, and gray mudstone and mud shale with carbonate nodules. Facies 1 through 3 record deposition in proximal to medial braided-stream channel, longitudinal bar and dune complexes. Facies 4 is a lowland, hydromorphic paleosol, and Facies 5 represents overbank and abandoned channel-fill sedimentation in an alluvial plain.

Handford, C.R.

1987-05-01

190

Sedimentology and palaeontology of the Upper Jurassic Puesto Almada Member (Cañadón Asfalto Formation, Fossati sub-basin), Patagonia Argentina: Palaeoenvironmental and climatic significance  

NASA Astrophysics Data System (ADS)

Six facies associations are described for the Puesto Almada Member at the Cerro Bandera locality (Fossati sub-basin). They correspond to lacustrine, palustrine, and pedogenic deposits (limestones); and subordinated alluvial fan, fluvial, aeolian, and pyroclastic deposits. The lacustrine–palustrine depositional setting consisted of carbonate alkaline shallow lakes surrounded by flooded areas in a low-lying topography. The facies associations constitute four shallowing upward successions defined by local exposure surfaces: 1) a Lacustrine–Palustrine-pedogenic facies association with a 'conchostracan'–ostracod association; 2) a Palustrine facies association representing a wetland subenvironment, and yielding 'conchostracans', body remains of insects, fish scales, ichnofossils, and palynomorphs (cheirolepidiacean species and ferns growing around water bodies, and other gymnosperms in more elevated areas); 3) an Alluvial fan facies association indicating the source of sediment supply; and 4) a Lacustrine facies association representing a second wetland episode, and yielding 'conchostracans', insect ichnofossils, and a palynoflora mainly consisting of planktonic green algae associated with hygrophile elements. The invertebrate fossil assemblage found contains the first record of fossil insect bodies (Insecta-Hemiptera and Coleoptera) for the Cañadón Asfalto Formation. The succession reflects a mainly climatic control over sedimentation. The sedimentary features of the Puesto Almada Member are in accordance with an arid climatic scenario across the Upper Jurassic, and they reflect a strong seasonality with periods of higher humidity represented by wetlands and lacustrine sediments.

Cabaleri, Nora G.; Benavente, Cecilia A.; Monferran, Mateo D.; Narváez, Paula L.; Volkheimer, Wolfgang; Gallego, Oscar F.; Do Campo, Margarita D.

2013-10-01

191

Modelling the response of an alluvial aquifer to anthropogenic and recharge stresses in the United States Southern Great Plains  

NASA Astrophysics Data System (ADS)

This paper uses Visual MODFLOW to simulate potential impacts of anthropogenic pumping and recharge variability on an alluvial aquifer in semi-arid northwestern Oklahoma. Groundwater withdrawal from the aquifer is projected to increase by more than 50% (relative to 1990) by the year 2050. In contrast, climate projections indicate declining regional precipitation over the next several decades, creating a potential problem of demand and supply. The following scenarios were simulated: (1) projected groundwater withdrawal, (2) a severe drought, (3) a prolonged wet period, and (4) a human adjustment scenario, which assumes future improvements in water conservation measures. Results indicate that the combined impacts of anthropogenic pumping and droughts would create drawdown of greater than 12 m in the aquifer. Spatially, however, areas of severe drawdown will be localized around large-capacity well clusters. The worst impacts of both pumping and droughts will be on stream-aquifer interaction. For example, the projected aquifer pumpage would lead to a total streamflow loss of 40%, creating losing stream system regionally. Similarly, a severe drought would lead to a total streamflow loss of >80%. A post-audit of the model was also carried out to evaluate model performance. By simulating various stress scenarios on the alluvial aquifer, this study provides important information for evaluating management options for alluvial aquifers.

Zume, Joseph T.; Tarhule, Aondover A.

2011-08-01

192

Fire, climate, and alluvial system dynamics: A Holocene record from Yellowstone National Park  

SciTech Connect

Many large debris-flow, hyperconcentrated-flow, and flood-streamflow sediment transport events have been produced in steep basins that were burned in the 1988 fires in northeaster Yellowstone National Park. The charcoal- and fines-rich character of fire-related debris-flow deposits and the abundance of similar facies in Holocene fan sections have allowed them to construct a [sup 14]C-dated chronology of fire-related sedimentation in the Soda Butte and Slough Creek drainages for the last 3500 years. Major periods of fire-related alluvial fan aggradation are interpreted as drought-dominated with the support of local paleoenvironmental data and statistical analyses of historical climate-fire relations; however, some fire-related events may occur due to high climatic variability and severe short-term drought within generally moist intervals. The last major episode of fire-related debris-flow activity encompasses the Medieval Warm Period of 900--1300 AD and peaks ca. 1150 AD; a prior episode culminates ca. 350--100 BC. Wetter periods contain minimal fire-related fan sedimentation; however, floodplain broadening and aggradation occurs along axial streams. Higher average snowmelt runoff discharges are probably involved, such that the dominant alluvial activity shifts to removal of sediment from alluvial fan storage and transport to downstream floodplains. The Little Ice Age (ca. 1300--1900 AD) contains minimal fire-related debris0flow activity and is associated with floodplain aggradation of the T4 terrace, and independent evidence suggests substantially wetter conditions during T3 aggradation ca. 350--650 AD. Thus, small-scale climate changes of the late Holocene effectively control the dominant mode of alluvial activity.

Meyer, G.A. (Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Geology); Wells, S.G. (Univ. of California, Riverside, CA (United States). Dept. of Earth Sciences); Jull, A.J. (Univ. of Arizona, Tucson, AZ (United States). NSF-Arizona Accelerator Facility For Isotope Dating)

1992-01-01

193

CHANNEL EVOLUTION IN MODIFIED ALLUVIAL STREAMS.  

USGS Publications Warehouse

This study (a) assesses the channel changes and network trends of bed level response after modifications between 1959 and 1972 of alluvial channels in western Tennessee and (b) develops a conceptual model of bank slope development to qualitatively assess bank stability and potential channel widening. A six-step, semiquantitative model of channel evolution in disturbed channels was developed by quantifying bed level trends and recognizing qualitative stages of bank slope development. Development of the bank profile is defined in terms of three dynamic and observable surfaces: (a) vertical face (70 to 90 degrees), (b) upper bank (25 to 50 degrees), and (c) slough line (20 to 25 degrees).

Simon, Andrew; Hupp, Cliff, R.

1987-01-01

194

Controls on alluvial fan long-profiles  

USGS Publications Warehouse

Water and debris flows exiting confined valleys have a tendency to deposit sediment on steep fans. On alluvial fans where water transport of gravel predominates, channel slopes tend to decrease downfan from ???0.10-0.04 to ???0.01 across wide ranges of climate and tectonism. Some have argued that this pattern reflects grain-size fining downfan such that higher threshold slopes are required just to entrain coarser particles in the waters of the upper fan, whereas lower slopes are required to entrain finer grains downfan (threshold hypothesis). An older hypothesis is that slope is adjusted to transport the supplied sediment load, which decreases downfan as deposition occurs (transport hypothesis). We have begun to test these hypotheses for alluvial fan long-profiles using detailed hydraulic and particle-size data in sediment transport models. On four alluvial fans in the western U.S., we find that channel hydraulic radiiare largely 0.5-0.9 m at fan heads, decreasing to 0.1-0.2 m at distal margins. We find that median gravel diameter does not change systematically along the upper 60%-80% of active fan channels as slope declines, so downstream gravel fining cannot explain most of the observed channel slope reduction. However, as slope declines, channel-bed sand cover increases systematically downfan from areal fractions of <20% above fan heads to distal fan values in excess of 70%. As a result, entrainment thresholds for bed material might decrease systematically downfan, leading to lower slopes. However, current models of this effect alone tend to underpredict downfan slope changes. This is likely due to off-channel gravel deposition. Calculations that match observed fan long-profiles require an exponential decline in gravel transport rate, so that on some fans approximately half of the load must be deposited off channel every -0.20-1.4 km downfan. This leads us to hypothesize that some alluvial fan long-proffies are statements about the rate of overbank deposition of coarse particles downfan, a process for which there is currently no mechanistic theory. ?? 2007 Geological Society of America.

Stock, J. D.; Schmidt, K. M.; Miller, D. M.

2008-01-01

195

Late Cretaceous to Mid-Tertiary Basin Evolution in the Central Tibetan Plateau: Changing Environments in Response to Tectonic Partitioning, Aridification, and Regional Elevation Gain  

NASA Astrophysics Data System (ADS)

Located in the Bangong-Nujiang suture (BNS) between the Lhasa and Qiangtang terranes of central Tibet, the Nima basin records Cretaceous through Late Miocene sediment accumulation during a period of drastically changing paleogeography, paleoclimate, and paleoelevation. The BNS formed during Latest Jurassic-Early Cretaceous time as the Lhasa terrane collided with the Qiangtang terrane. During Early to mid-Cretaceous time the region was located at or below sea level. By Aptian time (115 Ma), Nima basin was above sea level and strongly influenced by local volcanic activity and crustal shortening in the reactivated BNS zone. In the southern Nima basin, a roughly 50 Myr (Late Cretaceous through Paleocene) depositional hiatus correlates with significant crustal shortening and ensuing voluminous ignimbrite eruptions in the Lhasa terrane. In the northern Nima basin, deposition continued during latest Cretaceous time, recording arid paleoclimate in evaporitic lacustrine and eolian dunefield deposits. By Oligocene time the Nima basin comprised two depocenters accumulating coarse-grained alluvial, fluvial, lacustrine (evaporitic) and fan-delta deposits in close association with reactivated thrusts in the BNS zone. Stable carbon and oxygen isotopic data indicate that climate was arid and regional paleoelevation during the Late Oligocene was about 4.7 km, as it is today. Overall the Nima basin depositional record, combined with structural and geochronological studies, demonstrates that the BNS was reactivated during mid-Cretaceous and mid-Tertiary time, that the intervening 50 Myr interval was a time of regional upper crustal shortening in the Lhasa terrane followed by widespread ignimbrite eruptions, and that arid paleoclimate and high paleoelevation were established by Late Cretaceous and Late Oligocene time, respectively. Within the context of other data sets from the Lhasa terrane, the Nima record is consistent with low-angle subduction of Neotethyan oceanic lithosphere during Early Cretaceous time, followed by shortening within the Gangdese retroarc and northern Lhasa terrane thrust belts during mid- Cretaceous to early Tertiary time (105 to 50 Ma), accompanied, but also outlasted, by lithospheric delamination/dripping and regional magmatic flare-up during latest Cretaceous through Eocene time, followed by underthrusting of Indian lower crust and lithosphere as far north as the BNS during Late Oligocene time.

Decelles, P. G.; Kapp, P.

2006-12-01

196

Quantifying relative and absolute sediment yields from petrographic data: the Dora Baltea basin (Western Alps)  

Microsoft Academic Search

The Dora Baltea River, sourced in the Mt. Blanc massif, cuts transversally across all Alpine tectonic domains. The drainage basin covers an area of 3930 km^2, with (<=) 20% in the Piedmont alluvial-plain. The Dora Baltea mountain basin was divided in 20 sub-basins (one for each of the 16 major tributaries, and 4 tracts of the trunk river). Topographic and

G. Vezzoli

2003-01-01

197

Monti Martani (umbria, Italy) Alluvial Fans: Hazards Sites and Occurrence  

NASA Astrophysics Data System (ADS)

In this paper we proposed modeling and simulation approaches for testing the debris flows occurrence hypothesis. The approach is an empirically and process based, and use multiple physically-based simulations to evaluate hazard down-slope from initiation sites in alluvial fans of the Terni basin-northern area (Umbria, Italy). The northern part of the area is bounded by the M. Martani normal fault that controls the drainage network where produces a large debris piedimont deposition. The main fault scarp is cut by narrow streams that represents the dominant constructional process by three alluvial fans generations. Field-based and remote sensing observations from the area will be used to provide a sound empirical evaluation of the new landslide occurrence hypothesis. In humid, soil-mantled environments in particular, debris flow always originate in fine-scale valleys in steep, rhythmically dissected terrain. Concave planform contours define topographic swales, referred to as "hollows" in the nomenclature, that typically contain colluvial soils significantly thicker than those found on adjacent slope. Areas underlain by massive, resistant bedrock, show that the majority of debris flows originated in colluvium-filled hollows. Hollows consequently define a mappable debris flow hazard. The association of debris flow with hollows is governed by relations between sediment transport, hillslope hydrology and slope stability. Consequently, colluvial deposits in hollows are particularly susceptible to landsliding. Furthermore topographic converge also focuses subsurface runoff into hollows, so high intensity rainfall cells indicate that a lack of historic landsliding from specific hollow is by no means an indicator of future stability. The strong likelihood that the 25m resolution DEM can be used in this project means that we will have the topographic control to do more detailed modeling of hill slope hydrology to account for spatial and temporal variability in groundwater saturation on hillslopes, and the consequences for slope failure. We will use a software tools for multiflow routing of runoff given a precipitation model, a DEM, and a probabilistic model of finding pockets of colluvium on hillslopes which is demonstrated for the synthetic hillslope.

Taramelli, A.; Melelli, L.

198

Fertilizers mobilization in alluvial aquifer: laboratory experiments  

NASA Astrophysics Data System (ADS)

In alluvial plains, intensive farming with conspicuous use of agrochemicals, can cause land pollution and groundwater contamination. In central Po River plain, paleo-channels are important links between arable lands and the underlaying aquifer, since the latter is often confined by clay sediments that act as a barrier against contaminants migration. Therefore, paleo-channels are recharge zones of particular interest that have to be protected from pollution as they are commonly used for water supply. This paper focuses on fertilizer mobilization next to a sand pit excavated in a paleo-channel near Ferrara (Italy). The problem is approached via batch test leaking and columns elution of alluvial sediments. Results from batch experiments showed fast increase in all major cations and anions, suggesting equilibrium control of dissolution reactions, limited availability of solid phases and geochemical homogeneity of samples. In column experiments, early elution and tailing of all ions breakthrough was recorded due to preferential flow paths. For sediments investigated in this study, dispersion, dilution and chemical reactions can reduce fertilizers at concentration below drinking standards in a reasonable time frame, provided fertilizer loading is halted or, at least, reduced. Thus, the definition of a corridor along paleo-channels is recommended to preserve groundwater quality.

Mastrocicco, M.; Colombani, N.; Palpacelli, S.

2009-02-01

199

Influences of Alluvial Fans on Upland Watersheds in Central Nevada  

Microsoft Academic Search

Geomorphic, hydrologic, and vegetation processes of upland watersheds in central Nevada are influenced by side-valley alluvial fans. Discontinuous longitudinal stream profiles and spatial variation in stream channel incision are often associated with the alluvial fans. In many cases, groundwater flow is restricted immediately upstream of side-valley fans resulting in elevated water tables and the occurrence of springs and seeps. Riparian

John L. Korfmacher; Jeanne C. Chambers

200

Detectability of minerals on desert alluvial fans using reflectance spectra  

Microsoft Academic Search

The visible and near-infrared reflectance spectra of soil samples collected from desert alluvial and colluvial surfaces in the Cuprite mining district, Nevada, were analyzed. These surfaces are downslope from hydrothermally altered volcanic rocks that contain spectrally characteristic minerals such as alunite and kaolinite. Coarse fractions of the soils on the alluvial fans are mineralogically variable and express the upslope lithologies;

Hugh Shipman; John B. Adams

1987-01-01

201

Movement of water infiltrated from a recharge basin to wells.  

PubMed

Local surface water and stormflow were infiltrated intermittently from a 40-ha basin between September 2003 and September 2007 to determine the feasibility of recharging alluvial aquifers pumped for public supply, near Stockton, California. Infiltration of water produced a pressure response that propagated through unconsolidated alluvial-fan deposits to 125 m below land surface (bls) in 5 d and through deeper, more consolidated alluvial deposits to 194 m bls in 25 d, resulting in increased water levels in nearby monitoring wells. The top of the saturated zone near the basin fluctuates seasonally from depths of about 15 to 20 m. Since the start of recharge, water infiltrated from the basin has reached depths as great as 165 m bls. On the basis of sulfur hexafluoride tracer test data, basin water moved downward through the saturated alluvial deposits until reaching more permeable zones about 110 m bls. Once reaching these permeable zones, water moved rapidly to nearby pumping wells at rates as high as 13 m/d. Flow to wells through highly permeable material was confirmed on the basis of flowmeter logging, and simulated numerically using a two-dimensional radial groundwater flow model. Arsenic concentrations increased slightly as a result of recharge from 2 to 6 µg/L immediately below the basin. Although few water-quality issues were identified during sample collection, high groundwater velocities and short travel times to nearby wells may have implications for groundwater management at this and at other sites in heterogeneous alluvial aquifers. PMID:21740423

O'Leary, David R; Izbicki, John A; Moran, Jean E; Meeth, Tanya; Nakagawa, Brandon; Metzger, Loren; Bonds, Chris; Singleton, Michael J

2011-07-08

202

Variability in alluvial rocks, determined from TM analysis, and its tectonic significance  

NASA Astrophysics Data System (ADS)

This study demonstrates that images generated from Thematic Mapper data are valuable for sedimentologic analysis of a depositional basin. A ratio composite color image was used to identify and regionally map large-scale lithologic packages in the alluvial Willwood Formation. The facies were further distinguished using field sedimentologic criteria. The spatial distribution of facies demonstrates that east-west trending lineaments extend from the Bighorn Mountains westward into the Bighorn Basin, Wyoming and were active faults during early Eocene time. The lithologic heterogeneity is attributed to differential crustal subsidence on either side of the lineaments. This caused topographic gradients and variability in local moisture regimes, which influenced the location of major stream channels and the types of paleosols that formed. Temporal changes in lithology record a regional change to increase dryness followed by a return to moister conditions, culminating in the development of lacustrine deposits.

Kraus, Mary J.

203

Influence of salts on the microbial activities in arid and semi-humid soils.  

PubMed

The influence of salt mixtures consisting of Ca(H2PO4)2, trace elements, CaSO4, CaCO3, Na2CO3, NaCl and K2SO4 in different combinations on the nitrifying power, evolution of carbon dioxide and the total number of bacteria was studied in arid soils (sandy and alluvial) and semi-humid ones (chernozem and rendzina). Salt mixtures comprising of either mono-calcium phosphate or sodium chloride showed highly inhibiting action on the studied microbial activities in sandy, alluvial and chernozem soils, whilst mono-calcium phosphate stimulated the heterotrophs of rendzina. Trace elements stimulated the autotrophs of the clay soils. The other different salts mixtures acted according to the salt combination and nature of the microbial activity. PMID:1189993

El-Shinnawi, M M

1975-01-01

204

Influence of salts on the microbial activity in arid and simi-humid soils.  

PubMed

The influence of salt mixtures consisting of Ca (H2PO4)2, trace elements, CaSO4, CaCO3, Na2CO3, NaCl, and K2SO4 in different combinations on the nitrifying power, evolution of carbon dioxide, and the total number of bacteria was studied in arid soils (sandy and alluvial) and semi-humid ones (chernozem and rendzina). Salt mixtures comprising either monocalcium phosphate or sodium chloride showed highly inhibiting action on the studied microbial activities in sandy, alluvial, and chernozem soils, while monocalcium phosphate stimulated the heterotrophs of rendzina. Trace elements favoured the autotrophs of the caly soils. The other different salt mixtures acted according to the salt combination and nature of the microbial activity. PMID:910575

El-Shinnawi, M M; Seifert, J

1977-01-01

205

Sand-flat/playa mud-flat-lacustrine cycles in Fundy rift basin (Triassic-Jurassic), Nova Scotia: implications for climatic and tectonic controls  

SciTech Connect

Blomidon Formation red beds comprise over 200 m-scale cycles of (1) sand-flat sandstone (distal alluvial-fan deposits) and (2) playa sandy mudstone and/or lacustrine claystones. Rift basin subsidence and local sagging along the Glooscap fault system generated sand-flat/playa mud-flat cycles by shifting loci of active fan sedimentation toward and away from the playa surface as fan lobes migrated toward topographic lows. Episodes of intense aridity are recorded in the sand-flat and playa mud-flat deposits where amalgamated sheetflood packages are characterized by pervasive evaporite mineralization (principally gypsum) controlled by subsurface evolution of a Ca-SO/sub 4/-Na-Cl brine. Aridity is further evidenced by significant disruption of sedimentary fabrics beneath evaporite crusts, deep mud cracks, eolian sandstone layers and patches, and precipitation of authigenic calcium and magnesium-rich illite/smectite and analcime. Carbon isotopic data from early formed, low-magnesium calcite cements (pre-gypsum) reflect slightly to moderately elevated subsurface salinities that accompanied initial brine evolution. During relatively wetter periods, lacustrine platy claystones accumulated in shallow, oxidizing lakes that lapped onto the sand flats. Claystone units lack evaporite minerals and textures, and many units are partially burrowed. Carbon isotopic data from calcite cements are consistently lighter than sand-flat/playa mud-flat calcites and were in equilibrium with relatively fresh subsurface pore waters.

Mertz, K.A. Jr.; Hubert, J.F.

1989-03-01

206

Flood susceptibility assessment in a highly urbanized alluvial fan: the case study of Sala Consilina (southern Italy)  

NASA Astrophysics Data System (ADS)

This paper deals with the risk assessment to alluvial fan flooding at the piedmont zone of carbonate massifs of the southern Apennines chain (southern Italy). These areas are prime spots for urban development and are generally considered to be safer than the valley floors. As a result, villages and towns have been built on alluvial fans which, during intense storms, may be affected by flooding and/or debris flow processes. The study area is located at the foothills of the Maddalena mountains, an elongated NW-SE trending ridge which bounds to the east the wide intermontane basin of Vallo di Diano. The area comprises a wide detrital talus (bajada) made up by coalescent alluvial fans, ranging in age from the Middle Pleistocene to the Holocene. Historical analysis was carried out to ascertain the state of activity of the fans and to identify and map the zones most hit by past flooding. According to the information gathered, the Sala Consilina fans would appear prone to debris flows; in the past these processes have produced extensive damage and loss of life in the urban area. The watershed basins feeding the fans have very low response times and may produce debris flow events with high magnitudes. Taking into account the historical damage, the fan surface morphology, and the present urban development (street orientation and hydraulic network), the piedmont area was zoned and various susceptibility classes were detected. These results may represent a useful tool for studies aiming at territorial hazard mapping and civil protection interventions.

Santangelo, N.; Santo, A.; di Crescenzo, G.; Foscari, G.; Liuzza, V.; Sciarrotta, S.; Scorpio, V.

2011-10-01

207

ARTICLE A brief history of Great Basin pikas  

Microsoft Academic Search

Aim Within the past few decades, seven of the 25 historically described populations of American pikas (Ochotona princeps) in the Great Basin of arid western North America appear to have become extinct. In this paper, the prehistoric record for pikas in the Great Basin is used to place these losses in deeper historical context. Location The Great Basin, or area

Donald K. Grayson

208

Chloride mass-balance method for estimating ground water recharge in arid areas: Examples from western Saudi Arabia  

USGS Publications Warehouse

The chloride mass-balance method, which integrates time and aerial distribution of ground water recharge, was applied to small alluvial aquifers in the wadi systems of the Asir and Hijaz mountains in western Saudi Arabia. This application is an extension of the method shown to be suitable for estimating recharge in regional aquifers in semi-arid areas. Because the method integrates recharge in time and space it appears to be, with certain assumptions, particularly well suited for and areas with large temporal and spatial variation in recharge. In general, recharge was found to be between 3 to 4% of precipitation - a range consistent with recharge rates found in other arid and semi-arid areas of the earth.

Bazuhair, A. S.; Wood, W. W.

1996-01-01

209

Alluvial Bars of the Obed Wild and Scenic River, Tennessee  

USGS Publications Warehouse

In 2004, the U.S. Geological Survey (USGS) and the National Park Service (NPS) initiated a reconnaissance study of alluvial bars along the Obed Wild and Scenic River (Obed WSR), in Cumberland and Morgan Counties, Tennessee. The study was partly driven by concern that trapping of sand by upstream impoundments might threaten rare, threatened, or endangered plant habitat by reducing the supply of sediment to the alluvial bars. The objectives of the study were to: (1) develop a preliminary understanding of the distribution, morphology, composition, stability, and vegetation structure of alluvial bars along the Obed WSR, and (2) determine whether evidence of human alteration of sediment dynamics in the Obed WSR warrants further, more detailed examination. This report presents the results of the reconnaissance study of alluvial bars along the Obed River, Clear Creek, and Daddys Creek in the Obed WSR. The report is based on: (1) field-reconnaissance visits by boat to 56 alluvial bars along selected reaches of the Obed River and Clear Creek; (2) analysis of aerial photographs, topographic and geologic maps, and other geographic data to assess the distribution of alluvial bars in the Obed WSR; (3) surveys of topography, surface particle size, vegetation structure, and ground cover on three selected alluvial bars; and (4) analysis of hydrologic records.

Wolfe, W. J.; Fitch, K. C.; Ladd, D. E.

2007-01-01

210

An overview of experiences of basin artificial recharge of ground water in Japan  

NASA Astrophysics Data System (ADS)

In this paper, the author reviews the present situation of basin artificial recharge of ground water (MAR: managed aquifer recharge) as of 2007 in Japan. Most of the artificial recharge of basin method is carried out using alluvial fans. The enhancing groundwater resources in the Rokugo alluvial aquifer has resulted in sustainability for the groundwater environment, especially in the distal fan. As a general judgment, the basin artificial recharge contributes to sustainable aquifer management in alluvium. As a result of this review, the basin artificial recharge will be utilized more in the future, not only in Japan, but in monsoon Asian countries as well.

Hida, Noboru

211

Design of flood protection for transportation alignments on alluvial fans  

SciTech Connect

The method of floodplain delineation on alluvial fans developed for the national flood insurance program is modified to provide estimates of peak flood flows at transportation alignments crossing an alluvial fan. The modified methodology divides the total alignment length into drainage design segments and estimates the peak flows that drainage structures would be required to convey as a function of the length of the drainage design segment, the return period of the event, and the location of the alignment on the alluvial fan. An example of the application of the methodology is provided. 16 refs., 5 figs.

French, R.H.

1991-01-01

212

ROLES OF NATURAL LEVEES ON THE ARA RIVER ALLUVIAL FAN  

NASA Astrophysics Data System (ADS)

For the comprehensive flood control measures for alluvial fans, it is required to understand the effects of natural levees and micro-topography on reducing flood damages. We investigate the role of natural levees in the flood control measures for the alluvial fan of the Ara River by mapping historical community development and using the hazard maps.As a result, it is clarified that many communities have been developed on natural levees, and that natural levees are resistant to spreading of flood waters. The above indicates the significance of researches on natural levees and micro-topography as control measures on alluvial fans.

Saito, Shigeru; Fukuoka, Shoji

213

Mass balance from alluvial fan isopachs: a case study from the Chinese Tian Shan  

NASA Astrophysics Data System (ADS)

Continental surfaces are incessantly reworked through erosion and sedimentation. Markers of erosion within drainage areas are often scarce and temporary, but at the outlet of mountain belts, more continuous and perennial records of deposition can be found in alluvial fans. These fans are constructed by the deposition through time of the coarse part of sediments transported by rivers. Volume of sediments trapped in alluvial fans can then be used in order to reconstruct sediment fluxes coming out from their catchment areas and the associated erosion rates. Quantifying such erosion rates is of great interest for the study of mass transfer. It is also necessary to understand relief dynamics, as well as the influence of tectonic and climate on this dynamics. We propose here a complete method to estimate erosion fluxes from alluvial fans in a specific area, the northern piedmont of the Tian Shan in China. Along the piedmont of this range, series of fans of different ages are clearly identified. In particular, abandoned fans (which were active before 10 000 years ago) are well preserved in the landscape, and easily identifiable on satellite images. These fans have been deeply incised during the last deglaciation (about 10 000 years ago), and therefore, their basal surface can be observed. In this specific area, it is then possible to obtain field constraints on the real fan thickness. First, we draw a morpho-sedimentary map of the fans and their drainage basins. Then, we went on the field to estimate the fan thickness wherever it is possible. Finally, based on this data set, and on geometrical considerations, we built isopach maps of the fans and calculate their volumes. These 3D reconstructions can then be compared to the geometrical relationships classically used to assess alluvial fan volumes from their upper surface only. Erosion rates of ten drainage basins can be derived from these volumes, allowing a sink to source investigation, for the period of fan activity. In north Tian Shan, these erosion rates can be compared with other values calculated from bedload measurements and cosmogenic data, providing thus an opportunity to discuss results coming from different methods

Guerit, Laure; Barrier, Laurie; Métivier, François; Jolivet, Marc; Fu, Bihong

2013-04-01

214

Causes of farmland salinization and remedial measures in the Aral Sea basin—Research on water management to prevent secondary salinization in rice-based cropping system in arid land  

Microsoft Academic Search

In the Lower Syr Darya region of the Aral Sea basin, secondary salinization of irrigated lands has been a crucial problem. To clarify the mechanism of secondary salinization, studies on water and salt behavior were conducted in an irrigation block where a rice-based cropping system has been practiced. Results of on-site studies are summarized as follows: (1) since the performance

Yoshinobu Kitamura; Tomohisa Yano; Toshimasa Honna; Sadahiro Yamamoto; Koji Inosako

2006-01-01

215

Annual plants in arid and semi-arid desert regions  

Microsoft Academic Search

Annual plants are the main vegetation in arid and semi-arid desert regions. Because of their unique traits, they are the optimal\\u000a experimental subjects for ecological studies. In this article, we summarize annual plants’ seed germination strategies, seedling\\u000a adaptability mechanism to environments, seed dispersal, and soil seed banks. We also discuss the biotic and abiotic factors\\u000a affecting the composition and dynamics

Xuehua Li; Xiaolan Li; Deming Jiang; Zhimin Liu; Qinghe Yu

2008-01-01

216

Microbial communities of alluvial soils in the Volga River delta  

NASA Astrophysics Data System (ADS)

The number and biomass of the microbial community in the upper humus horizon (0-20 cm) were determined in the main types of alluvial soils (mucky gley, desertified soddy calcareous, hydrometamorphic dark-humus soils) in the Volga River delta. Fungal mycelium and alga cells predominate in the biomass of the microorganisms (35-50% and 30-47%, respectively). The proportion of prokaryotes in the microbial biomass of the alluvial soils amounts to 2-6%. No significant seasonal dynamics in the number and biomass of microorganisms were revealed in the alluvial soils. The share of carbon of the microbial biomass in the total carbon content of the soil organic matter is 1.4-2.3% in the spring. High coefficients of microbial mineralization and oligotrophy characterize the processes of organic matter decomposition in the alluvial soils of the mucky gley, desertified soddy calcareous, and hydrometamorphic dark humus soil types.

Sal'Nikova, N. A.; Polyanskaya, L. M.; Tyugai, Z. N.; Sal'Nikov, A. N.; Egorov, M. A.

2009-01-01

217

Late alluvial fan formation in southern Margaritifer Terra, Mars  

Microsoft Academic Search

Crater statistics show alluvial fans are much younger than previously thoughtFans formed in the Amazonian to near the Hesperian-Amazonian boundaryFan distribution requires a late period of regional water-driven degradation

John A. Grant; Sharon A. Wilson

2011-01-01

218

Environmental impacts on the hydrology of ephemeral streams and alluvial aquifers  

NASA Astrophysics Data System (ADS)

In arid and semi-arid regions alluvial groundwater resources of ephemeral streams are highly important for water supplies and ecosystems. Recent projects have studied processes of indirect recharge in situ and in detail (Dahan et al., 2008; Klaus et al., 2008). Still, little is known about the vulnerability of these aquifers to environmental impacts like surface dam constructions, land-use changes and climatic conditions as well as the time and type of response to such external impacts. With a catchment size of about 30.000 km² the Swakop River in Namibia is the largest of the country's twelve major ephemeral streams draining westwards into the Atlantic Ocean. The alluvial groundwater resources have been affected by the construction of two major surface water dams in the upper catchment as well as by abstractions for rural water supply, farming and mining downstream of the constructed dams (referred to as lower catchment). The determination of environmental impacts in the Swakop River catchment is difficult due to scarce hydrometric and water quality data. In order to obtain a better understanding of the hydrological system under changing environmental conditions a spatially distributed environmental tracer approach was applied. A longitudinal profile of groundwater samples was taken within a field study along the alluvial aquifer of the Swakop River. The samples were analysed for stable isotopes (18O, 2H), major ions and trace elements as well as for the residence time indicators CFC and SF6. The combined application of groundwater residence time analysis, stable isotope measurements and hydrochemical characterisation was used in order to associate a time scale with groundwater quality data. This method provides dated information on recharge and water quality before and after dam construction and can be used to detect environmental impacts on the hydrological system. CFC-12 analysis resulted in recharge years ranging from 1950 (0.01 pmol/l) to 1992 (1.4 pmol/l). Seven of 14 groundwater samples represent mainly groundwater recharged before or between the construction of surface water dams (1970 and 1978), the remaining samples represent groundwater recharge after dam construction. The groundwater residence time is generally short (recharge mainly after 1980) in the upper catchment and much higher (recharge mainly before 1980 and before dam construction) in the lower part of the catchment. Combining the age and isotope information shows how the surface water dams modified the pattern of groundwater recharge. The lower catchment has been partly cut off from the upper part in terms of indirect groundwater recharge by floods which means that most large floods originating in the headwaters of the Swakop River do not reach the lower alluvial aquifer anymore. The relationship between groundwater age and groundwater constituents helped to define baselines of hydrological properties (origin of water, recharge altitude) and of hydrochemical composition prior to the construction of dams (and other anthropogenic impacts). The well defined relationship between groundwater age and altitude of the river further helps to assess how fast different segments will be affected by these environmental impacts. References Dahan, O., Tatarsky, B., Enzel, Y., Kuells, C., Seely, M., Benito, G. (2008) Dynamics of Flood Water Infiltration and Ground Water Recharge in Hyperarid Desert. Ground Water, Vol. 46, 3. (6-2008), pp. 450-461. Klaus, J., Kuells, C., Dahan, O. (2008): Evaluating the recharge mechanism of the Lower Kuiseb Dune Area using mixing cell modeling and residence time data. Journal of Hydrology, v. 358, p. 304-316.

Kuells, C.; Marx, V.; Bittner, A.; Ellmies, R.; Seely, M.

2009-04-01

219

The Role of Climatic Change in Alluvial Fan Development  

Microsoft Academic Search

Alluvial fans develop at the base of drainages where feeder channels release their solid load (Blair and McPherson, 2009;\\u000a Leeder et al., 1998; Harvey et al., 2005). A classic fan-shape forms where there is a well-defined topographic apex. Multiple\\u000a feeder channels, however, often blur the fan-shape resulting in a merged bajada. Alluvial fans can be found in almost all\\u000a terrestrial

Ronald I. Dorn

220

The "alluvial mesovoid shallow substratum", a new subterranean habitat.  

PubMed

In this paper we describe a new type of subterranean habitat associated with dry watercourses in the Eastern Iberian Peninsula, the "Alluvial Mesovoid Shallow Substratum" (alluvial MSS). Historical observations and data from field sampling specially designed to study MSS fauna in the streambeds of temporary watercourses support the description of this new habitat. To conduct the sampling, 16 subterranean sampling devices were placed in a region of Eastern Spain. The traps were operated for 12 months and temperature and relative humidity data were recorded to characterise the habitat. A large number of species was captured, many of which belonged to the arthropod group, with marked hygrophilous, geophilic, lucifugous and mesothermal habits. In addition, there was also a substantial number of species showing markedly ripicolous traits. The results confirm that the network of spaces which forms in alluvial deposits of temporary watercourses merits the category of habitat, and here we propose the name of "alluvial MSS". The "alluvial MSS" may be covered or not by a layer of soil, is extremely damp, provides a buffer against above ground temperatures and is aphotic. In addition, compared to other types of MSS, it is a very unstable habitat. It is possible that the "alluvial MSS" may be found in other areas of the world with strongly seasonal climatic regimes, and could play an important role as a biogeographic corridor and as a refuge from climatic changes. PMID:24124544

Ortuño, Vicente M; Gilgado, José D; Jiménez-Valverde, Alberto; Sendra, Alberto; Pérez-Suárez, Gonzalo; Herrero-Borgoñón, Juan J

2013-10-04

221

The "Alluvial Mesovoid Shallow Substratum", a New Subterranean Habitat  

PubMed Central

In this paper we describe a new type of subterranean habitat associated with dry watercourses in the Eastern Iberian Peninsula, the “Alluvial Mesovoid Shallow Substratum” (alluvial MSS). Historical observations and data from field sampling specially designed to study MSS fauna in the streambeds of temporary watercourses support the description of this new habitat. To conduct the sampling, 16 subterranean sampling devices were placed in a region of Eastern Spain. The traps were operated for 12 months and temperature and relative humidity data were recorded to characterise the habitat. A large number of species was captured, many of which belonged to the arthropod group, with marked hygrophilous, geophilic, lucifugous and mesothermal habits. In addition, there was also a substantial number of species showing markedly ripicolous traits. The results confirm that the network of spaces which forms in alluvial deposits of temporary watercourses merits the category of habitat, and here we propose the name of “alluvial MSS”. The “alluvial MSS” may be covered or not by a layer of soil, is extremely damp, provides a buffer against above ground temperatures and is aphotic. In addition, compared to other types of MSS, it is a very unstable habitat. It is possible that the “alluvial MSS” may be found in other areas of the world with strongly seasonal climatic regimes, and could play an important role as a biogeographic corridor and as a refuge from climatic changes.

Ortuno, Vicente M.; Gilgado, Jose D.; Jimenez-Valverde, Alberto; Sendra, Alberto; Perez-Suarez, Gonzalo; Herrero-Borgonon, Juan J.

2013-01-01

222

Water sources accessed by arid zone riparian trees in highly saline environments, Australia.  

PubMed

The flow regimes of arid zone rivers are often highly variable, and shallow groundwater in the alluvial aquifers can be very saline, thus constraining the availability and quality of the major water sources available to riparian trees-soil water, shallow groundwater and stream water. We have identified water sources and strategies used by riparian trees in more highly saline and arid conditions than previously studied for riparian trees of arid zone rivers. Our research focused on the riparian species Eucalyptus coolabah, one of the major riparian trees of ephemeral arid zone rivers in Australia. The water sources available to this riparian tree were examined using delta(18)O isotope data from xylem, soil water, groundwater and surface water. Additionally, soil chloride and matric potential data were used to infer zones of water availability for root uptake. Despite the saline conditions, the trees used a mixture of soil water and groundwater sources, but they did not use surface water directly. The study identified three strategies used to cope with typically high groundwater and soil water salinities. Firstly, the trees preferentially grow in zones of most frequent flushing by infiltrating streamflow, such as the bank-tops of channels. Secondly, the trees limit water use by having low transpiration rates. Thirdly, the trees are able to extract water at very low osmotic potentials, with water uptake continuing at chloride concentrations of at least 20,000-30,000 mg L(-1). PMID:18270743

Costelloe, Justin F; Payne, Emily; Woodrow, Ian E; Irvine, Elizabeth C; Western, Andrew W; Leaney, Fred W

2008-02-13

223

Quaternary climate change and hillslope processes: What can we learn from alluvial fans?  

NASA Astrophysics Data System (ADS)

Examining the timing of sediment deposition on alluvial fans may clarify relationships among Quaternary changes in climate, sediment production, and sediment removal from uplifted mountain blocks. Deposition on fans indicates that (1) ample sediment is available for transport within contributing basins and (2) that stream power is adequate to move that sediment to the fan environment. Dating alluvial fan deposition clarifies relationships among climatically controlled factors (e.g. precipitation, vegetation, temperature), and hydrologic and geomorphic responses (e.g. weathering rates, frost action, glaciation, stream power) that influence landscape evolution. Numerous 2-5 km radius, low gradient alluvial fans head along the western side of the Lost River Range (LRR) in east-central Idaho. Timing of deposition on these fans is based on optically stimulated luminescence dating (OSL). In addition we described general deposit characteristics and mapped different aged fan surfaces to explore how fan deposition has changed over time. OSL results indicate that evacuation of sediment from contributing basins and deposition on fans was enhanced ~10-14 ka and ~40-50 ka. The younger episode is more robust in this record, with deposition recorded on all five studied fans despite differences in Quaternary glacial extent in contributing basins that varied from ~0-80%. Glacial chronologies from the nearby Sawtooth Range (Thackray, 2008) and Yellowstone-Teton region (Licciardi and Pierce, 2008; Gosse et al, 1995) suggest that this time period may have coincided with and followed the last glacial maxima in the northern Rocky Mountains. Deposition during the ~40-50 ka episode is recorded on the two largest studied fans, both with <10% glaciation in basin areas, as well as a ~40 m terrace of the East Fork Big Lost River that drains the Pioneer Range west of the LRR. A ~60-65 ka moraine in the northern LRR dated by U-series on pedogenic carbonate, an extensive glacio-fluvial terrace in the Wind River Basin (~200 km east of the LRR) dated to >55 ± 8.6 ka (Sharp et al, 2003), and substantial loess accumulation near the Teton Range at ~46-54 ka (Pierce et al, personal comm.) suggest that this episode of fan deposition was late- to post-glacial with respect to the MIS 4 glaciation and associated climatic conditions. Deposition on alluvial fans generally results from (1) increases in the sediment supply and/or (2) changes in stream power that alter the relative balance between sediment supply and stream power. In this region, sediment supply could increase following glacial conditions if reduced effective moisture decreases hillslope vegetation cover, freeing accumulated regolith for transport to fans, or greater temperature fluctuations increase the effectiveness of frost weathering. Stream power following a glacial maxima may have decreased in response to effectively drier climate, but may still have been adequate to transport sediment to fans. It’s also possible that stream power increased following glacial maxima with greater frequency of stochastic events such as rain on snow.

Kenworthy, M.; Pierce, J. L.; Rittenour, T. M.; Sharp, W. D.; Pierce, K. L.

2009-12-01

224

Mt. Chambers Creek alluvial fan - a recorder for Late Quaternary flow regime changes along the eastern Flinders Ranges (South Australia)  

NASA Astrophysics Data System (ADS)

Climate is a primary control on Late Quaternary alluvial fan evolution and past hydrological changes should be sensitively recorded in alluvial fan stratigraphy. The Flinders Ranges (S Australia) are situated between tropical and extra-tropical (e.g. westerlies) elements of the atmospheric circulation. Numerous alluvial fans constitute the transition between the Flinders Ranges and the large salt lake system of Lake Frome to the east. Along the arid eastern margin of the Flinders Ranges, geomorphology and stratigraphy were investigated at Mt. Chambers Creek alluvial fan (31°S). The fan is connected to a ~380 km2 catchment via the Mt. Chambers gorge, which has incised into the uplifted range front. Upstream of the gorge, manifold exposures along valley fills provide evidence for a generally fining-upward sequence of fluvial gravels and (eolian?) silts, which are topped by thick layers of tufa that have subsequently incised. Downstream of the apex, the alluvial fan surface is characterized by relatively low slopes (~0.5° - 1.5°) and a complex pattern of desert pavements, overlain by several inactive feeder channels and/or floodouts. The modern channel drains into an active floodout approximately 13 km downstream of the fan apex, showing that significant quantities of coarse-grained sediment load do not currently reach the baselevel at Lake Frome. Mt. Chambers Creek has incised several meters into the fan body, exposing extensive outcrops of alluvial fan sediments and paleosols. Generally, the fan stratigraphy can be divided into six different units, each of them bounded by laterally continuous and mostly carbonaceous paleosol horizons. The lowermost four units are dominated by matrix- and clast supported gravels, indicating high-energy events such as hyperconcentrated and debris flows. Along the distal fan, the thickness of these units and grain size generally decreases, locally exposing a sequence of well-developed and buried desert pavements. In combination, these observations imply environmental conditions favourable of increased frequency and/or magnitude during the deposition of units 1-4 under wetter climatic conditions. In contrast, unit 5 consists of silts and carbonatic gravel deposits, containing numerous fragments of well-rounded carbonate nodules, likely indicating the onset of upstream erosion leading to reworking of paleosols and tufa deposits. The uppermost unit 6 is composed of mainly fluvial sands and pebbles and seems to be limited to the distal fan, where it corresponds to the currently observed floodout dynamics. In combination with new radiocarbon and OSL dates (currently in progress), the correlation of downstream alluvial fan stratigraphy and upstream catchment dynamics provides the base for a much more reliable reconstruction of alluvial fan history and flow regime changes over the Late Quaternary. Thereby, our results will provide an important link between existing regional paleoclimatic records from Lake Frome (lake level variations) and the Flinders Ranges (loessic valley fills), eventually helping to decipher the relative roles of the southern westerlies vs. tropical moisture sources over the Late Quaternary.

May, Jan-Hendrik; Larsen, Joshua; Cohen, Timothy; Nanson, Gerald

2010-05-01

225

Quantifying macropore recharge: Examples from a semi-arid area  

USGS Publications Warehouse

The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered to be the difference between total recharge through floors of topographically dosed basins and interstitial recharge through the same area. On the regional scale, macropore recharge was considered to be the difference between regional average annual recharge and interstitial recharge measured in the unsaturated zone. Stable isotopic composition of ground water and precipitation was used us an independent estimate of macropore recharge on the regional scale. Results of this analysis suggest that in the Southern High Plains recharge flux through macropores is between 60 and 80 percent of the total 11 mm/y. Between 15 and 35 percent of the recharge occurs by interstitial recharge through the basin floors. Approximately 5 percent of the total recharge occurs as either interstitial or matrix recharge between the basin floors, representing approximately 95 percent of the area. The approach is applicable to other arid and semi-arid areas that focus rainfall into depressions or valleys.The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in arid and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered to be the difference between total recharge through floors of topographically closed basins and interstitial recharge through the same area. On the regional scale, macropore recharge was considered to be the difference between regional average annual recharge and interstitial recharge measured in the unsaturated zone. Stable isotopic composition of ground water and precipitation was used as an independent estimate of macropore recharge on the regional scale. Results of this analysis suggest that in the Southern High Plains recharge flux through macropores is between 60 and 80 percent of the total 11 mm/y. Between 15 and 35 percent of the recharge occurs by interstitial recharge through the basin floors. Approximately 5 percent of the total recharge occurs as either interstitial or matrix recharge between the basin floors, representing approximately 95 percent of the area. The approach is applicable to other arid and semi-arid areas that focus rainfall into depressions or valleys.

Wood, W. W.; Rainwater, K. A.; Thompson, D. B.

1997-01-01

226

Effects of the Biofuels Initiative on Water Quality and Quantity in the Mississippi Alluvial Plain  

NASA Astrophysics Data System (ADS)

In the search for renewable fuel alternatives, biofuels have gained strong political momentum. In the last decade, extensive mandates, policies, and subsidies have been adopted to foster the development of a biofuels industry in the United States. The manifestation of the Biofuels Initiative in the Mississippi Delta was a 47-percent decrease in cotton acreage with a concurrent 288 percent increase in corn acreage in 2007. Because corn uses 80 percent more water for irrigation than cotton, and more nitrogen fertilizer is recommended for corn cultivation, this crop type change has implications for water quantity and quality in the Delta. Increased water use for corn is accelerating water-level declines in the Mississippi River Valley alluvial aquifer at a time when conservation is being encouraged due to concerns about sustainability. A mathematical model calibrated to existing conditions in the Delta shows that increased fertilizer applications on corn will increase the extent of nitrate movement into the alluvial aquifer. Estimates based on surface-water modeling results indicate that higher application rates of nitrogen from increased corn production increases the amount of nitrogen exported from the Yazoo River basin to the Gulf of Mexico by about 7 percent; increasing the Delta’s contribution to hypoxic conditions in the Gulf of Mexico.

Welch, H. L.; Green, C. T.; Coupe, R. H.

2010-12-01

227

Long term trend in groundwater levels and watershed condition in the Kurobe River alluvial fan in Japan  

Microsoft Academic Search

The Kurobe River alluvial fan is one of the most popular alluvial fans in Japan. The difference in elevation from Aimoto where is the top of the alluvial fan to seashore is approximately 130m, and the slope of the alluvial fan is approximately 10 degrees. The Kurobe River alluvial fan is consisted of conglomerate layers and has had many flowing

T. Tebakari

2010-01-01

228

Alluvial-fan and lacustrine fan-delta sedimentation in west-central California during the Middle Tertiary transition from subduction to transform tectonics  

Microsoft Academic Search

The Plush Ranch (PR) Formation was deposited in one of several sedimentary basins in west-central California. The PR consists of more than 1,800 m of nonmarine sedimentary rocks and interbedded basaltic volcanic rocks that together record a complicated history of synsedimentary faulting, volcanism, and deposition in alluvial-fan, fan-delta, and lacustrine depositional settings. The sedimentological analysis indicates that both the northern

R. B. Cole; R. G. Stanley

1992-01-01

229

Facies analysis of the old Red Sandstone of Spitsbergen (Wood Bay Formation): Reconstruction of the depositional environments and implications of basin development  

Microsoft Academic Search

Summary  The object of this paper is to provide a facies guide that helps subsequent workers recognizing different facies and palaeoenvironments\\u000a of the terrestrial old Red Sandstone exposed in central N Spitsbergen. Sediments of the Early Devonian Wood Bay Formation\\u000a represent continental molasse deposition under arid to semi-arid climatic conditions in three main depositional environments\\u000a (rivers, alluvial plains, perennial lakes) represented

Dierk Blomeier; Max Wisshak; Winfried Dallmann; Eden Volohonsky; André Freiwald

2003-01-01

230

Groundwater Recharge Evaluation in Semi-Arid Northeast Mexico in Response to Projected Climate Change  

Microsoft Academic Search

This research evaluates the effects of projected climate change on mountain recharge in the semi-arid Cuatrocinegas Basin (CCB) of northeast Mexico. The CCB UNESCO Biosphere Reserve is located in Coahuila, Mexico (~27° N, ~102° W) and includes > 500 springs that discharge from a regional flow system to wetlands with > 70 endemic species and to an irrigation network. This

B. D. Wolaver

2007-01-01

231

U- and Th-Series Transport in a Sandy Aquifer in an Arid Climate  

Microsoft Academic Search

We investigated the transport of U-Th series nuclides of an aquifer in an arid region with low flow velocities, the Ojo Alamo Aquifer of the San Juan Basin, which has 14C water ages up to 25 kyr (Phillips et al. 1989; Stute et al. 1995). The study aims to test a theoretical transport model by Tricca et al. (2000) with

B. C. Reynolds; G. J. Wasserburg

2001-01-01

232

Preservation of daily tidal cycles and stacked alluvial swamp deposits: Depositional response to early compaction of buried peat bodies  

SciTech Connect

The character of the clastic depositional environments represented in the lower Mary Lee coal zone of the Pennsylvanian Pottsville Formation in the Warrior basin Alabama (tidally influenced mud flats and alluvial swamps) was controlled by the compaction of buried peat bodies. The lowest mineable coal in the Mary Lee coal zone, the Jagger, is overlain by laminated shale and sandstone exhibiting pronounced cycle bedding. This bedding records daily tidal cyclicity in the form of sand-mud couplets. These correspond to flood-current deposition of the coarser fraction followed by fallout of the finer grained fraction during ensuing slack-water periods. These couplets are cyclically bundled-sandier bundles corresponding to spring tides and muddier bundles to neap tides (lamination counts suggest a 24-30-day cycle). The clastic sequence above the overlying Blue Creek coal is characterized by a series of stacked alluvial swamp horizons. These can be identified by autochthonous fossil plants and pedological features indicative of gleyed paleosols. Catastrophic flooding buried and preserved these horizons. The rapid, early compaction of the buried Jagger and Blue Creek peat bodies created accommodation space that allowed both the preservation of tidalites in the Jagger coal to Blue Creek coal interval and the stacking of alluvial swamp paleosols above the Blue Creek seam. Carboniferous peats were comprised of highly compressible plant parts and hence, were sensitive to sediment loading. Once the peat bodies had compressed to a certain extent, stability of the overlying sediment surface created conditions amenable to resumption of peat accumulation.

Demko, T.M.; Gastaldo, R.A. (Auburn Univ., AL (USA))

1990-05-01

233

Tectonic controls on the geomorphic evolution of alluvial fans in the Piedmont Zone of Ganga Plain, Uttarakhand, India  

NASA Astrophysics Data System (ADS)

The Piedmont Zone is the least studied part of the Ganga Plain. The northern limit of the Piedmont Zone is defined by the Himalayan Frontal Thrust (HFT) along which the Himalaya is being thrust over the alluvium of the Ganga Plain. Interpretation of satellite imagery, Digital Terrain Models (DTMs) and field data has helped in the identification and mapping of various morphotectonic features in the densely forested and cultivated Piedmont Zone in the Kumaun region of the Uttarakhand state of India. The Piedmont Zone has formed as a result of coalescing alluvial fans, alluvial aprons and talus deposits. The fans have differential morphologies and aggradation processes within a common climatic zone and similar litho-tectonic setting of the catchment area. Morphotectonic analysis reveals that the fan morphologies and aggradation processes in the area are mainly controlled by the ongoing tectonic activities. Such activities along the HFT and transverse faults have controlled the accommodation space by causing differential subsidence of the basin, and aggradation processes by causing channel migration, channel incision and shifting of depocentres. The active tectonic movements have further modified the landscape of the area in the form of tilted alluvial fan, gravel ridges, terraces and uplifted gravels.

Goswami, Pradeep K.; Pant, Charu C.; Pandey, Shefali

2009-06-01

234

Digital-model simulation of the Toppenish alluvial aquifer, Yakima Indian Reservation, Washington  

USGS Publications Warehouse

Increasing demands for irrigating additional lands and proposals to divert water from the Yakima River by water users downstream from the Yakima Indian Reservation have made an accounting of water availability important for present-day water management in the Toppenish Creek basin. A digital model was constructed and calibrated for the Toppenish alluvial aquifer to help fulfill this need. The average difference between observed and model-calculated aquifer heads was about 4 feet. Results of model analysis show that the net gain from the Yakima River to the aquifer is 90 cubic feet per second, and the net loss from the aquifer to Toppenish Creek is 137 cubic feet per second. Water-level declines of about 5 feet were calculated for an area near Toppenish in response to a hypothetical tenfold increase in 1974 pumping rates. (USGS)

Bolke, E. L.; Skrivan, James A.

1981-01-01

235

Discharge estimation from planform characters of the Shedhi River, Gujarat alluvial plain: Present and past  

NASA Astrophysics Data System (ADS)

In the absence of long-term hydrologic and streamflow records an understanding of river morphology (present and past) can help delineate changes in magnitudes of water and sediment discharges. The relict drainage system of Gujarat alluvial plain provides an opportunity to reconstruct the palaeochannel morphology-related discharge estimations. In this paper, based on the geomorphological evidence and channel geometry, an attempt has been made to reconstruct the palaeohydrological condition in the Shedhi River during the Holocene. A comparison of the present day channel of the Shedhi River with that of its palaeo counterpart reveals that the former was carrying much higher bankfull discharge (˜5500m3 s-1) as compared to the present (˜200m3 s-1). This is attributed to a larger drainage area and enhanced precipitation in the Shedhi River basin.

Sridhar, Alpa

2007-08-01

236

Loess is the accumulation of dust, not evidence for aridity  

NASA Astrophysics Data System (ADS)

Loess-paleosol sequences (LPS) are valuable terrestrial archives for Quaternary climate and environmental changes. The famous sections on the Chinese Loess Plateau, for example, document the alternation of warm and humid interglacials (paleosols) and cold and more arid glacials (loess). This, at least partly, reflects the weakening of the monsoonal circulation during glacials and has led to the notion that loess in general documents more arid conditions. Paleosols, on the other hand, are often interpreted to document more humid conditions. We studied the LPS Crvenka in the Carpathian Basin, southeast Europe, which spans the full last glacial cycle, and obtained results that do not fit the above concept: (i) The analysis of plant-derived long-chain n-alkanes indicates the presence of deciduous trees and shrubs during glacials, i.e. sufficient precipitation for tree growth, whereas tree-less grass steppes seem to have prevailed during the Eemian, the last interglacial. (ii) Compound-specific deuterium analyses on the alkanes show only little changes on glacial-interglacial timescale. When compared with the isotopic enrichment of the Mediterranean Sea during the last glacial, this likely documents a combination of increased rainfall, reduced evapo-transpiration and reduced temperatures. (iii) Novel lipid biomarkers derived from soil bacteria (GDGTs, glycerol dialkyl glycerol tetraethers) also indicate humid glacials (BIT index close to 1) and more arid interglacials (BIT<0.8). Our results are in good agreement with modelling studies suggesting a southward shift of the westerlies during glacials, and aridization in the Mediterranean area in response to man-made global warming. More importantly, they remind us of an important fact: Loess is the accumulation of dust, but not (necessarily) evidence for aridity. Pedogenesis may simply not have been able to keep pace with high glacial dust accumulation rates related to intense glacial, periglacial and fluvial activity. Proxies independent of accumulation rates should be further developed and applied in LPS.

Zech, Roland

2013-04-01

237

Caribbean basin framework, 3: Southern Central America and Colombian basin  

SciTech Connect

The authors recognize three basin-forming periods in southern Central America (Panama, Costa Rica, southern Nicaragua) that they attempt to correlate with events in the Colombian basin (Bowland, 1984): (1) Early-Late Cretaceous island arc formation and growth of the Central American island arc and Late Cretaceous formation of the Colombian basin oceanic plateau. During latest Cretaceous time, pelagic carbonate sediments blanketed the Central American island arc in Panama and Costa Rica and elevated blocks on the Colombian basin oceanic plateau; (2) middle Eocene-middle Miocene island arc uplift and erosion. During this interval, influx of distal terrigenous turbidites in most areas of Panama, Costa Rica, and the Colombian basin marks the uplift and erosion of the Central American island arc. In the Colombian basin, turbidites fill in basement relief and accumulate to thicknesses up to 2 km in the deepest part of the basin. In Costa Rica, sedimentation was concentrated in fore-arc (Terraba) and back-arc (El Limon) basins; (3) late Miocene-Recent accelerated uplift and erosion of segments of the Central American arc. Influx of proximal terrigenous turbidites and alluvial fans in most areas of Panama, Costa Rica, and the Colombian basin marks collision of the Panama arc with the South American continent (late Miocene early Pliocene) and collision of the Cocos Ridge with the Costa Rican arc (late Pleistocene). The Cocos Ridge collision inverted the Terraba and El Limon basins. The Panama arc collision produced northeast-striking left-lateral strike-slip faults and fault-related basins throughout Panama as Panama moved northwest over the Colombian basin.

Kolarsky, R.A.; Mann, P. (Univ. of Texas, Austin (United States))

1991-03-01

238

Understanding Hydrologic Processes in Semi-Arid Cold Climates  

NASA Astrophysics Data System (ADS)

Water shortages destabilize economies and ecosystems. These shortages are caused by complex interactions between climate variability, ecosystem processes, and increased demand from human activities. In the semi-arid region of the northwestern U.S., water availability during drought periods has already reached crisis levels and the problems are expected to intensify as the effects of global climate change and population growth continue to alter the supply and demand patterns. Many of the problems are critical to this region because hydropower, agriculture, navigation, fish and wildlife survival, water supply, tourism, environmental protection, and water-based recreation are vital to state economies and our way of life. In order to assess the spatial and temporal nature of hydrologic responses, consistent and comprehensive long-term data sets are needed. In response to these needs, we would like to propose the Spokane River drainage basin as a long-term hydrologic observatory. The Spokane River basin is located in eastern Washington and northern Idaho and is a tributary of the Columbia River. The watershed consists of several major surface water tributaries as well as natural and man-made lakes and reservoirs. With headwaters beginning in the Rocky Mountains, the drainage area is approximately 6,640 mi2. In addition to providing an excellent study area for examining many conventional water resource problems, the Spokane River watershed also presents a unique opportunity for investigating many of the hydrologic processes found in semi-arid cold climates. Snowfall in the watershed varies spatially between 35 inches near the mouth of the basin to over 112 inches at the headwaters. These varied hydrologic uses provide a unique opportunity to address many common challenges faced by water resource professionals. This broad array of issues encompasses science, engineering, agriculture, social sciences, economics, fisheries, and a host of other disciplines. In addition, because precipitation patterns in this semi-arid region tend to be temporally distributed, storage and global climate change issues are significant.

Barber, M. E.; Beutel, M.; Lamb, B.; Watts, R.

2004-12-01

239

Biodiversity in arid regions: values and perceptions  

Microsoft Academic Search

With their modest rainfall, arid regions are characterized by relatively fewer species than the better-watered biomes. But this makes it all the more important that the biodiversity that is present in arid environments be given even higher priority; for each species lost from an arid region, the percentage of loss for the region's biodiversity is much higher than in more

J. A. McNeely

2003-01-01

240

Hydrological Responses to Climate Change and to LUCC in Asian Arid Zone  

NASA Astrophysics Data System (ADS)

The arid Asian zone is one of the most sensitive areas to the global climate change. For instance, the temperature has been rising at a rate of 0.39K/10yrs in the arid northwestern China during the past an half of century, being 2.78 times of the global average. In the arid Asian zone, water resource is a key factor restricting the socio-economic development and threatening the ecological security. Under the global warming conditions, water resource systems of the arid Asian zone are most likely becoming increasingly vulnerable, especially under the projected increasing population and expanding economy in arid Asian zone. Hydrological data from glacier-supplied rivers in the Tian Shan Mountains for example show that the runoff has been increasing primarily as a result of rising temperature that caused increases in ice melting. But, the decreasing trend of surface runoff in low-elevation basins is undeniable and the decreasing trend is attributable to the increasingly intensified human activities. Specifically, increasingly intensified water consumption for irrigation and the associated massive constructions of water conservancy projects were responsible for the decreasing trend of runoff. And, the decreasing trend has been severely jeopardizing the ecological security in the lower reaches of the arid river basins. In arid northwestern China, about 85% of the water resources are formed in high elevations and the glacier-melting contribution to runoff has been doubled since 1980's. Approaching to the turning point of glacier-melting supplies to runoff will pose a great threat to socio-economic sustainability and to ecological security. The turning point refers to the transition from increasing runoff to decreasing runoff within glacier-melting supplied watersheds under warming climate.

Feng, Zhaodong

2013-04-01

241

BIOGEOCHEMICAL FLUXES ACROSS PIEDMONT SLOPES OF THE JORNADA BASIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter is an overview of recent studies of the movement of water, sediment, and nutrients across a principle piedmont slope, or bajada, of the Jornada Basin. Bajadas are extensive, gently sloping surfaces formed by the coalescence of alluvial fans and are a major landscape component of the bas...

242

Hydrological Response of Semi-arid Degraded Catchments in Tigray, Northern Ethiopia  

NASA Astrophysics Data System (ADS)

To address water scarcity in the arid and semi-arid part of developing countries, accurate estimation of surface runoff is an essential task. In semi-arid catchments runoff data are scarce and therefore runoff estimation using hydrological models becomes an alternative. This research was initiated in order to characterize runoff response of semi-arid catchments in Tigray, North Ethiopia to evaluate SCS-CN for various catchments. Ten sub-catchments were selected in different river basins and rainfall and runoff were measured with automatic hydro-monitoring equipments for 2-3 years. The Curve Number was estimated for each Hydrological Response Unit (HRU) in the sub-catchments and runoff was modeled using the SCS-CN method at ? = 0.05 and ? = 0.20. The result showed a significant difference between the two abstraction ratios (P =0.05, df = 1, n= 132) and reasonable good result was obtained for predicted runoff at ? = 0.05 (NSE = -0.69; PBIAS = 18.1%). When using the CN values from literature runoff was overestimated compared to the measured value (e= -11.53). This research showed the importance of using measured runoff data to characterize semi-arid catchments and accurately estimate the scarce water resource. Key words: Hydrological response, rainfall-runoff, degraded environments, semi-arid, Ethiopia, Tigray

Teka, Daniel; Van Wesemael, Bas; Vanacker, Veerle; Hallet, Vincent

2013-04-01

243

An investigation into variable recharge behaviors among eight alluvial observation wells in Pajarito Canyon, Los Alamos, New Mexico  

NASA Astrophysics Data System (ADS)

Pajarito Canyon in Los Alamos, New Mexico trends west to east through the Pajarito Plateau from the headwaters in the Jemez Mountains, thirteen miles to the Rio Grande. In summer 2008, Los Alamos National Laboratory installed eight shallow wells, numbered PCAO-5, 6, 7a, 7b1, 7b2, 7c, 8 and 9, in the middle four miles of this canyon. Among these wells, five distinct recharge behaviors have been observed. PCAO-5 demonstrates seasonal recharge in response to annual snowmelt. PCAO-6, while just 400 feet further downstream, is considerably flashier and the well is often dry for months at a time. In PCAO-7a, 7b2 and 7c, another two miles downstream, the water level declined steadily since installation, with no recharge until spring 2010. PCAO-7b1 has not contained water since drilling. Downstream a further two miles, PCAO-8 and PCAO-9 were dry for the majority of 2009 and their hydrographs are more attenuated. This investigation was undertaken to explain the recharge behaviors of the wells, with the goal of improving site selection and design of alluvial wells to provide better representation of the alluvial aquifer. Water level data collected since July 2008 were used to compare the water columns of each well. Well construction diagrams were utilized to construct stratigraphic maps in order to compare well construction and lithology. Results indicate that PCAO-5 consistently contains water due to its location above a flood retention structure (FRS) and the placement of its screened interval immediately above the tuff layer, forcing water to travel through the screened interval. PCAO-6’s flashy, intermittent hydrograph is due to its location downstream of the FRS, and because the bottom of the screened interval rests 2.5 feet above the alluvium-tuff interface, providing a conduit below the screen of the well. The similar behaviors of PCAO-7a, 7b2 and 7c result from their near-identical construction, lithology and location. The general decline of water level until spring 2010 was due to near-drought conditions in 2009. PCAO-7a retained more water more consistently through 2009 because its screened interval rests on the alluvium-tuff interface, whereas PCAO-7b2 and 7c are both screened similarly to PCAO-6. PCAO-7b1, which has not contained water since drilling, has its screened interval within the tuff later, preventing alluvial groundwater from reaching the screen. The attenuated hydrographs of PCAO-8 and 9 are possibly due to their downstream location; in the semi-arid study area, much of the alluvial groundwater sourced in the mountains may already have infiltrated towards the deeper aquifers before reaching the lower portion of the canyon. These results indicate that shallow wells in areas with a lithology similar to the study area should be constructed with a screened interval that rests directly on the alluvium-tuff interface, thereby forcing flow through the screen. Additionally, deep barriers such as the FRS will greatly inhibit consistent flow of alluvial groundwater into shallow wells built immediately downstream of the barrier. Finally, shallow wells in the lower portions of semi-arid canyons may not consistently contain water because source water from the mountains may infiltrate too deep before reaching the wells.

Schmeer, S. R.

2010-12-01

244

WATER AND ENERGY BALANCES WITHIN THE JORNADA BASIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter describes general characteristics and components of the energy and water balances in arid regions, with specific examples from the Jornada Basin. Various research efforts to characterize the energy and water balances and resultant carbon dioxide fluxes in the Jornada Basin are detailed....

245

A summary of methods for the collection and analysis of basic hydrologic data for arid regions  

USGS Publications Warehouse

This report summarizes and discusses current methods of collecting and analyzing the data required for a study of the basic hydrology of arid regions. The fundamental principles behind these methods are no different than those that apply to studies of humid regions, but in arid regions the infrequent occurrence of precipitation, the great variability of the many hydrologic elements, and the inaccessibility of most basins usually make it economically infeasible to use conventional levels of instrumentation. Because of these economic considerations hydrologic studies in arid regions have been commonly of the reconnaissance type; the more costly detailed studies are generally restricted to experimental basins and to those basins that now have major economic significance. A thorough search of the literature and personal communication with workers in the field of arid-land hydrology provided the basis for this summary of methods used in both reconnaissance and detailed hydrologic studies. The conclusions reached from a consideration of previously reported methods are interspersed in this report where appropriate.

Rantz, S. E.; Eakin, T. E.

1971-01-01

246

Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)  

Microsoft Academic Search

An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction.

H. A. Wollenberg; J. S. Y. Wang; G. Korbin

1983-01-01

247

Alluvial aquifers in the Mzingwane catchment: Their distribution, properties, current usage and potential expansion  

Microsoft Academic Search

The Mzingwane River is a sand filled channel, with extensive alluvial aquifers distributed along its banks and bed in the lower catchment. LandSat TM imagery was used to identify alluvial deposits for potential groundwater resources for irrigation development. On the false colour composite band 3, band 4 and band 5 (FCC 345) the alluvial deposits stand out as white and

William Moyce; Pride Mangeya; Richard Owen; David Love

2006-01-01

248

Geology, Water, and Wind in the Lower Helmand Basin, Southern Afghanistan.  

National Technical Information Service (NTIS)

This report presents an overview of the geology, hydrology, and climate of the lower Helmand Basin, a large, closed, arid basin in southern Afghanistan. The basin is drained by the Helmand River, the only perennial desert stream between the Indus and Tigr...

J. W. Whitney

2006-01-01

249

A noncalibrated rainfall-runoff model for large, arid catchments  

NASA Astrophysics Data System (ADS)

A distributed, field-based rainfall-runoff model was developed for the 1400-km2 arid catchment of Nahal Zin, Israel. No calibration with measured flow data was performed. The model used rainfall radar input applied over a catchment that was spatially disaggregated into different terrain types according to hydrologically relevant surface characteristics. Hortonian overland flow generation on each type was parameterized independently using values of initial loss and temporal decay of infiltration determined from existing field experiments. Delimited by topography, this catchment wide pattern of rainfall excess was distributed over 850 tributary catchments (model elements). Runoff delivery from the model elements to the adjoining channel segments was timed by applying a mean response function determined in an environmentally similar experimental catchment. Inside the channel network the MVPMC3 method of the Muskingum-Cunge technique was used for streamflow routing, accounting for channel dimensions and roughness. For each channel segment a constant infiltration rate was applied to account for transmission losses and discontinued when the wetting front reached the bottom of the available alluvial storage. Within two model tests, one separate for the routing component (October 1979) and one for the complete model (October 1991), observed hydrographs and reconstructed peak discharges were successfully simulated. The spatially distributed model output showed that during the October 1991 test, tributaries produced preceding peaks that wetted the channel alluvium before the main flood had arrived and transmission losses lost their significance downstream. Total maximum model uncertainty was estimated including the uncertainty ranges of each model parameter. In general, this study shows that field-based data on generation and losses of runoff may be incorporated into a distributed hydrologic model to overcome calibration with the poor data records of arid high-magnitude events.

Lange, J.; Leibundgut, C.; Greenbaum, N.; Schick, A. P.

1999-07-01

250

HYDRAULIC ANALYSIS OF BASEFLOW AND BANK STORAGE IN ALLUVIAL STREAMS  

EPA Science Inventory

This paper presents analytical solutions, which describe the effect of time-variable net recharge (net accretion to water table) and bank storage in alluvial aquifers on the sustenance of stream flows during storm and inter-storm events. The solutions relate the stream discharge,...

251

Flooding and flow path selection on alluvial fans and deltas  

Microsoft Academic Search

The surfaces of alluvial fans and river deltas (collectively fans) are often dissected by a small number of channels radiating from the fan apex. On long timescales, channels migrate via avulsion, the process of channel bed deposition and abandonment that often results in catastrophic flooding and loss of life on densely populated fans. We present results of an experimental fan

Meredith D. Reitz; Douglas J. Jerolmack; John B. Swenson

2010-01-01

252

MAP OF ECOREGIONS OF THE MISSISSIPPI ALLUVIAL PLAIN  

EPA Science Inventory

The ecoregions of The Mississippi Alluvial Plain (73) have been identified, mapped, and described and provide a geographic structure for environmental resources research, assessment, monitoring, and management. This project is part of a larger effort by the U.S. EPA to create a ...

253

Catalogue of large alluvial fans in martian impact craters  

Microsoft Academic Search

We conducted a systematic, global survey using Thermal Emission Imaging System Infrared (THEMIS IR) coverage (?100 m\\/pixel) to search for large alluvial fans in impact craters on Mars. Our survey has focused on large fans (apron areas greater than ?40 km2, usually located in craters greater than 20 km in diameter) due to the resolution of the THEMIS images and

Erin R. Kraal; Erik Asphaug; Jeffery M. Moore; Alan Howard; Adam Bredt

2008-01-01

254

Microbial contamination of alluvial gravel aquifers by septic tank effluent  

Microsoft Academic Search

The effects of two methods of septic tank effluent disposal on the microbial quality of alluvial gravel aquifers were investigated at an experimental site in the Canterbury Plains, New Zealand. The movement of faecal coliform bacteria 9 m from a 5.5 m deep soakage pit into an unconfined aquifer, and 42 m from an 18 m deep injection bore into

L. W. Sinton

1986-01-01

255

Calcrete ‘fossilisation’ of alluvial fans in SE Spain: The roles of groundwater, pedogenic processes and fan dynamics in calcrete development  

NASA Astrophysics Data System (ADS)

Dryland alluvial fans developed along the northern flanks of the Sierra Lisbona in the north-western Vera basin (Almería region, southeast Spain) display negligible amounts of incision despite distal base-level lowering of > 30 m by the modern drainage network. The fans are of early-middle Quaternary age and are graded to a coeval river terrace, now isolated from the modern drainage network. The negligible incision is due to the encasement and ‘fossilisation’ of the alluvial fans by calcrete. This paper explores the reasons for such fossilisation and assesses the relative importance of pedogenic and groundwater mechanisms for calcrete formation within an alluvial fan setting. A single fan was selected for detailed examination. The geomorphological and sedimentological features of the fan, its catchment area and their relationship to the distal river terrace were documented. Qualitative and semi-quantitative petrographic and scanning electron microscope analyses of calcrete samples collected from transects across the fan surface, and within its distal top river terrace surface, enabled the style, pattern and relative timing of calcrete development to be assessed. Calcrete fabrics comprised initial micritic grain-coating cements, pellets and glaebular carbonate nodules, with interstitial spaces infilled by equant sparite and microsparite mosaics. It is proposed that the early phases of calcrete development were dominated by pedogenic processes with increasing groundwater calcretisation over time. Point count data indicated increased quantities of interstitial sparite and microsparite cement within near-surface proximal fan calcretes and at depth across the fan, suggesting that groundwater processes played a more important role in calcrete formation in these locations. The contribution of groundwater to calcrete development can be best explained by the intrinsic funnelling of groundwater from the catchment through the proximal fan head area, a zone where the fan gravels are thinnest. Calcrete ‘fossilisation’ appears to have followed a reduction in the fan catchment area as a result of rockfalls and watershed stream capture, which reduced water and sediment supply to the fan and enabled surface stabilization and calcrete development to take place. The reduced sediment/water supply, combined with calcrete fossilisation, appears to have protected the alluvial fans from regional base-level lowering. The implications of these results for existing pedostratigraphic models of calcrete development in alluvial fans are subsequently explored.

Stokes, Martin; Nash, David J.; Harvey, Adrian M.

2007-03-01

256

Modeling ground water flow in alluvial mountainous catchments on a watershed scale.  

PubMed

In large mountainous catchments, shallow unconfined alluvial aquifers play an important role in conveying subsurface runoff to the foreland. Their relatively small extent poses a serious problem for ground water flow models on the river basin scale. River basin scale models describing the entire water cycle are necessary in integrated water resources management and to study the impact of global climate change on ground water resources. Integrated regional-scale models must use a coarse, fixed discretization to keep computational demands low and to facilitate model coupling. This can lead to discrepancies between model discretization and the geometrical properties of natural systems. Here, an approach to overcome this discrepancy is discussed using the example of the German-Austrian Upper Danube catchment, where a coarse ground water flow model was developed using MODFLOW. The method developed uses a modified concept from a hydrological catchment drainage analysis in order to adapt the aquifer geometry such that it respects the numerical requirements of the chosen discretization, that is, the width and the thickness of cells as well as gradients and connectivity of the catchment. In order to show the efficiency of the developed method, it was tested and compared to a finely discretized ground water model of the Ammer subcatchment. The results of the analysis prove the applicability of the new approach and contribute to the idea of using physically based ground water models in large catchments. PMID:18459959

Wolf, Jens; Barthel, Roland; Braun, Jürgen

2008-05-02

257

Delineation of regional arid karstic aquifers: an integrative data approach.  

PubMed

This research integrates data procedures for the delineation of regional ground water flow systems in arid karstic basins with sparse hydrogeologic data using surface topography data, geologic mapping, permeability data, chloride concentrations of ground water and precipitation, and measured discharge data. This integrative data analysis framework can be applied to evaluate arid karstic aquifer systems globally. The accurate delineation of ground water recharge areas in developing aquifer systems with sparse hydrogeologic data is essential for their effective long-term development and management. We illustrate the use of this approach in the Cuatrociénegas Basin (CCB) of Mexico. Aquifers are characterized using geographic information systems for ground water catchment delineation, an analytical model for interbasin flow evaluation, a chloride balance approach for recharge estimation, and a water budget for mapping contributing catchments over a large region. The test study area includes the CCB of Coahuila, Mexico, a UNESCO World Biosphere Reserve containing more than 500 springs that support ground water-dependent ecosystems with more than 70 endemic organisms and irrigated agriculture. We define recharge areas that contribute local and regional ground water discharge to springs and the regional flow system. Results show that the regional aquifer system follows a topographic gradient that during past pluvial periods may have linked the Río Nazas and the Río Aguanaval of the Sierra Madre Occidental to the Río Grande via the CCB and other large, currently dry, upgradient lakes. PMID:18194323

Wolaver, Brad D; Sharp, John M; Rodriguez, Juan M; Flores, Juan Carlos Ibarra

2008-01-09

258

Occurrence of oil and gas fields and source rock transformation in the west Siberian basin and Barents Sea platform  

Microsoft Academic Search

The West Siberian and Barents Sea basins contain the largest demonstrated reserves of gas in the world (more than 33 trilion m[sup 3]) and very large recoverable reserves of oil (about 19 billion tons). The main productive reservoirs are of the Jurassic and Cretaceous and are composed of marine and alluvial sandstones. Major gas fields of the West Siberian basin

1993-01-01

259

Evolution of Devonian alluvial systems in an oblique-slip mobile zone—an example from the Broken River Province, northeastern Australia  

NASA Astrophysics Data System (ADS)

The lower 1500 m of the Late Devonian Bulgeri Formation was deposited in a tectonically active foreland basin in response to a major Late Devonian orogeny in the Broken River Province, northeastern Australia. The basin was bounded to the east by an uplifted belt of Palaeozoic sedimentary and volcanic rocks that was deformed east of an active thrust zone (Gray Creek Fault). To the south, the basin was bounded by igneous and metamorphic basement rocks, uplifted along a major oblique-slip fault zone (Clarke River Fault). Facies analysis and mapping of alluvial stratigraphy has resulted in the recognition of compositionally distinct, coalescing, axial and transverse alluvial drainage systems.The axial drainage system flowed to the northeast, approximately parallel to the Gray Creek Fault and away from the Clarke River Fault. The system drained the cratonic basement to the south and west, and accumulated mainly feldspathic and quartzose sediments. A lower, fine-grained succession, and an upper coarse-grained succession are recognised. The lower succession (‘Rockfields’ alluvial system) was deposited in broad, sandy, low-sinuosity channels and semi-permanent floodplain lakes. These rivers drained ultimately northward into a retreating coastal plain and shallow sea that lay over the Georgetown Province. The upper succession (‘Bulgeri’ alluvial system) was deposited in gravelly and sandy braided rivers emanating from south of the Clarke River Fault. The transverse distributary system (‘Stopem Blockem’ alluvial system), accumulated mainly lithic, coarse-grained sediments deposited in gravelly braided rivers sourced from the uplifted orogenic belt to the east. These rivers flowed towards the northwest before coalescing with the axial drainage system where they changed to a northerly orientation. Uplifted fault blocks of Devonian limestone within the basin locally contributed limestone gravel to these rivers. Between the coalescing axial and transverse river systems lay extensive floodplains, which received a slow, but compositionally mixed supply of mainly fine-grained sediments. Long periods of weathering resulted in the development of reddened palaeosols, with well developed calcrete horizons. The palaeogeography and fluvial style of the lower Bulgeri Formation is compared to the Gulf of Carpentaria in northeastern Australia.Analysis of the architecture of these alluvial systems has led to recognition of at least three, subsidence-driven, tectonic cyclothems and this is supported by simple quantitative modelling. The lower part of each cycle begins with a thin conglomeratic succession above an unconformity, and is overlain by thick, relatively fine-grained, syn-tectonic alluvial facies deposited during maximum subsidence. The upper part of each cycle is marked by increasingly coarse-grained, post-tectonic alluvial facies. These were deposited by gravel progradation following cessation of uplift or thrusting in the source areas and concomitant slowing of subsidence rates.

Lang, Simon C.

1993-05-01

260

Late Quaternary alluviation and offset along the eastern Big Pine fault, southern California  

NASA Astrophysics Data System (ADS)

Determining late Quaternary offset rates on specific faults within active mountain belts is not only a key component of seismic hazard analysis, but sheds light on regional tectonic development over geologic timescales. Here we report an estimate of dip slip rate on the eastern Big Pine oblique-reverse fault in the upper Cuyama Valley within the western Transverse Ranges of southern California, and its relation to local landscape development. Optically stimulated luminescence (OSL) dating of sandy beds within coarse-grained alluvial deposits indicates that deposition of alluvium shed from the Pine Mountain massif occurred near the southern margin of the Cuyama structural basin at the elevation of the Cuyama River between 25 and 14 ka. This alluvial deposit has been offset ˜ 10 m vertically by the eastern Big Pine fault, providing a latest Quaternary dip slip rate estimate of ˜ 0.9 m/ky based on a 50° fault dip. Incision of the adjacent Cuyama River has exposed a section of older Cuyama River sediments beneath the Pine Mountain alluvium that accumulated between 45 and 30 ka on the down-thrown footwall block of the eastern Big Pine fault. Corroborative evidence for Holocene reverse-slip on the eastern Big Pine fault is ˜ 1 m of incised bedrock that is characteristically exposed beneath 2 3.5 ka fill terraces in tributaries south of the fault. The eastern Big Pine fault in the Cuyama Valley area has no confirmed record of historic rupture; however, based on our results, we suggest the likelihood of multiple reverse-slip rupture events since 14 ka.

Delong, Stephen B.; Minor, Scott A.; Arnold, Lee J.

2007-10-01

261

Regional variation of As concentration in alluvial plain: An insight obtained from Mankyeong River plain, Korea  

NASA Astrophysics Data System (ADS)

The arsenic (As) concentrations in the groundwater of alluvial plains generally show high spatial variability. We geochemically explored the regional variation of As concentration from Mankyeong River floodplain. Even though its watershed is very small, it shows a close similarity to the Ganger-Megna-Bramaputra Plain of Bengal Basin in the occurrence of As-rich groundwater. Therefore, a precise investigation of the study area can provide important clues for the mechanisms causing the spatial variation of As concentrations in Bangladesh. We collected 163 groundwater samples from 122 shallow wells placed into the alluvial aquifer and analyzed for pH, Eh, alkalinity, DOC, As, Fe, Mn, Cl, SO4, NO3, NH4, PO4-P. 42 wells out of the investigated wells show As concentrations exceeding the drinking water limit (10 ug/L) and they are mostly distributed as a zone apart from the coast likely to those in Bangladesh. The As-rich groundwaters show high alkalinity, Fe, Mn, PO4, NH4, and DOC levels and very low NO3 and SO4 levels, indicating that the reductive dissolution of iron oxide is the main mechanism mobilizing As. In contrast, groundwater generally shows very low As and Fe concentrations in the coastal zone even though the waters are under much stronger reducing condition. Our results show that the limited supply of SO4 caused the high As concentration in the inland. But As concentrations were low in the coastal zone due to SO4 supplied by seawater intrusion. Very high alkalinity was observed in the coastal zone due to sulfate reduction, and which also plays a role decreasing As concentration by precipitating carbonate minerals such as siderite and rhodocrosite.

Kim, K.; Kim, S.; Kim, B.; Zhu, W.; Lee, E.; Ko, K.; Lee, K.

2010-12-01

262

Geostatistical simulations of alluvial sandbodies in the Triassic series of the Chaunoy field, France  

SciTech Connect

Chaunoy field, the largest oil field of the Paris basin, is exploiting heterogeneous reservoirs deposited during the Triassic in a large alluvial fan/lacustrine complex. The construction of a realistic reservoir model is difficult in such a setting because of the highly complex architecture of single reservoir units. Geostatistical simulations therefore have been performed to take into account the reservoir heterogeneities in the fluid flow modeling. A first layering has been determined from sedimentological and sequence stratigraphic analysis. The series was deposited in an alluvial outer fan environment. A lower siliciclastic member shows four heterogeneous sand sheets (7 m thick), which have been correlated across the field. Each of them is made up of stacked single channel sequences. The sand sheets are separated by extensive lacustrine and flood plain mudstone layers acting as permeability barriers. An upper siliciclastic/dolomitic member has been divided into two units with porous conglomeratic channels interfingered with cemented lagoonal dolomites. Proportional curves in lithofacies have confirmed this layering, showing the continuity of the permeability barriers, and the variogram analysis has shown that the well spacing is larger than the channel width. Simulations in lithofacies have been performed with the Heresim software using three different variogram ranges (small, medium, and large values). Because a good correlation exists between the lithofacies and the petrophysical attributes, a transcription of the lithofacies simulations into petrophysical attributes therefore was easy and realistic. Scaling-up techniques have given fluid-flow models corresponding to the three correlation ranges. Comparison of the global results of the fluid flow simulations with the observed production history enabled us to choose the more relevant case. The the model using the selected correlation range helped determine optimum well spacing.

Eschard, R.; Desaubliaux, G.; Eemouzy, P. (Institut Francais du Petrole, Rueil Malmaison (France)); Bacchiana, C.; Parpant, J.; Chautru, J.M.

1993-09-01

263

Landform map of the Kaiparowits Coal-Basin area, Utah  

SciTech Connect

A 1:125,000 scale map of the Kaiparowits Coal-Basin area of Utah is presented. The map portrays the shape and erosional resistance of and features, and it is intended to be a modified slope-analysis map for use by planners in their identification of areas suitable for transportation routes and construction sites. Depositional landforms such as alluvial flats, stream courses, dune fields, and alluviated pediments are shown, and a stratigraphic section of the rocks in the area is provided. (JMT)

Sargent, K.A.; Hansen, D.E.

1980-01-01

264

Lessons from Australian Water Reform for the Colorado River Basin (Invited)  

Microsoft Academic Search

The Murray Darling Basin in Australia (MDB) and the Colorado River Basin (CRB) share many geographical, climatic, and legal similarities. Both are predominantly arid, approximately the same size, occupy similar latitudes, have major snowmelt tributaries as well as very arid tributaries, were allocated by interstate agreements early in the 20th century, have multi-year carryover storage, are threatened by mid-latitude climate

B. Udall

2010-01-01

265

Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia  

NASA Astrophysics Data System (ADS)

The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr-1 rainfall), such as parts of Australia's Murray-Darling Basin (MDB). In this unique study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8-1.2 m depth under perennial vegetation and at 2.0-2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91-229 t ha-1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ?10 m depth that is not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m-1 at 21 to 37 m depth (N = 5), whereas deeper groundwater was less saline (290 mS m-1) with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM) software package predicted deep drainage of 3.3-9.5 mm yr-1 (0.7-2.1% rainfall) based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total), and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditionsafter changes in land use and a thick clay dominated vadose zone. This is in contrast to regional groundwater modelling that assumes annual recharge of 0.5% of rainfall. Importantly, it was found that leaching from episodic deep drainage could not cause discharge of saline groundwater in the area, since the water table was several meters below the incised river bed.

Timms, W. A.; Young, R. R.; Huth, N.

2011-11-01

266

Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia  

NASA Astrophysics Data System (ADS)

The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr-1 rainfall, potential evapotranspiration >2000 mm yr-1) such as parts of Australia's Murray-Darling Basin (MDB). In this rare study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8-1.2 m depth under perennial vegetation and at 2.0-2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91-229 t ha-1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ? 10 m depth that was not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m-1 at 21 to 37 m depth (N = 5), whereas deeper groundwater was less saline (290 mS m-1) with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM) software package predicted deep drainage of 3.3-9.5 mm yr-1 (0.7-2.1% rainfall) based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent soil water content, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total), and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge appears to be negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditions after changes in land use and a thick clay dominated vadose zone. This is in contrast to regional groundwater modelling that assumes annual recharge of 0.5% of rainfall. Importantly, it was found that leaching from episodic deep drainage could not cause discharge of saline groundwater in the area, since the water table was several meters below the incised river bed.

Timms, W. A.; Young, R. R.; Huth, N.

2012-04-01

267

The role of hydraulic lift on seedling establishment under a nurse plant species in a semi-arid environment  

Microsoft Academic Search

Hydraulic lift (HL) has been shown to improve performance of species occurring next to a plant engaged in HL, but whether this process plays an important role in seedling survival and growth in arid environments remains largely unknown. Here, we tested the influence of HL on the interaction between Retama sphaerocarpa, a nurse lifter shrub from western Mediterranean basin, and

Iván Prieto; Francisco M. Padilla; Cristina Armas; Francisco I. Pugnaire

2011-01-01

268

Stratigraphy of Pennsylvanian detrital reservoirs, Permian basin  

SciTech Connect

Significant oil reserves have been found to date in stratigraphic traps in Pennsylvanian detrital reservoirs on the Central Basin platform and Reagan uplift of the Permian basin. The 32 MMBOEG Arenoso field area, discovered in 1966, is the largest producing field. Along a 75 mi northwest-southeast trend, 23 other smaller fields will produce an average 850 MBOEG each, for a total estimated ultimate recovery to date in the trend of 52 MMBOEG. These stratigraphic traps are elusive and complex. However, reservoir quality is excellent, and because of the poorly understood trap types, significant reserves remain to be found in the trend. The Pennsylvanian detrital consists of chert cobble conglomerates, coarse sands, red shales, and gray limestones deposited in an environment that grades seaward from alluvial fan to braided stream to shallow marine. The chert cobble conglomerates of the alluvial fan facies and the coarse sands of the braided stream facies are the highest quality pay zones. Porosities range from 5 to 20%, with permeability ranging up to 26 d. The total unit is seldom more than 400 ft thick; reservoir rock thicknesses within the unit range up to 100 ft. Because of the complex nature of the alluvial fan and braided stream deposits, dry development wells can be expected within fields. These Strawn deposits are located adjacent to and overlying the eroded lower Paleozoic uplifts of the southern Central Basin platform. The major source of the chert cobbles is erosion of the Devonian tripolitic chert. Renewed structural uplift combined with sea level drop in the middle Wolfcampian locally truncated some Pennsylvanian detrital alluvial fan deposits, and complicated or destroyed a potential trap by depositing Wolfcamp chert conglomerates on top of the Pennsylvanian conglomerates.

Van Der Loop, M. (Arco Oil and Gas Co., Midland, TX (United States))

1992-04-01

269

Integrating hydrologic modeling and land use projections for evaluation of hydrologic response and regional water supply impacts in semi-arid environments  

Microsoft Academic Search

Semi-arid environments are generally more sensitive to urbanization than humid regions in terms of both hydrologic modifications\\u000a and water resources sustainability. The current study integrates hydrologic modeling and land use projections to predict long-term\\u000a impacts of urbanization on hydrologic behavior and water supply in semi-arid regions. The study focuses on the Upper Santa\\u000a Clara River basin in northern Los Angeles

Minxue HeTerri; Terri S. Hogue

270

Assessment of reference evapotranspiration methods in semi-arid regions: Can weather forecast data be used as alternate of ground meteorological parameters?  

Microsoft Academic Search

In this study, the performance of three empirical methods for estimating reference evapotranspiration (ET0): Makkink (Mak) and Priestley–Taylor (PT) (radiation-based) and Hargreaves–Samani (HARG) (temperature-based) were assessed in semi-arid regions. The values of ET0 derived using these three methods were compared to those estimated using the reference FAO Penman–Monteith (FAO-PM) method under semi-arid conditions of the Tensift basin (central of Morocco)

S. Er-Raki; A. Chehbouni; S. Khabba; V. Simonneaux; L. Jarlan; A. Ouldbba; J. C. Rodriguez; R. Allen

2010-01-01

271

Use of Thermal Infrared Multispectral Scanner (TIMS) imagery to investigate upslope particle size controls on arid piedmont morphology  

NASA Astrophysics Data System (ADS)

Geomorphic differences between slopes backing two distinct desert piedmont types provide a proxy indicator for the kind of landform developed at the corresponding mountain base. Here, the term 'bedrock pediment' describes subaerial bedrock platforms that emanate from a mountain base while 'alluvial slope' describes suballuvial bedrock platforms that extend from the mountain. Mountain slopes backing bedrock pediments have been demonstrated to be mantled by larger clast sizes than corresponding slopes backing alluvial slopes in the Phoenix region, Arizona, USA. The present research focuses on using the disparate particle sizes between slopes backing bedrock pediments and alluvial slopes as an indicator for the piedmont form developed at the mountain base, and uses high-resolution remotely sensed digital data as a medium for quantitative landform assessments. A gravel + bedrock versus soil index developed from airborne midinfrared multispectral imagery acquired by the Thermal Infrared Multispectral Scanner (TIMS) indicates the presence of slopes mantled with larger particle sizes versus slopes mantled with smaller particle sizes and greater soil coverage. Two test areas confirm the applicability of this method and further demonstrate the usefulness of high-resolution midinfrared multispectral imagery as a geomorphic tool in arid regions.

Applegarth, Michael T.; Stefanov, William L.

2006-12-01

272

Efficient upscaling of hydraulic conductivity in heterogeneous alluvial aquifers  

Microsoft Academic Search

An efficient method to upscale hydraulic conductivity (K) from detailed three-dimensional geostatistical models of hydrofacies heterogeneity to a coarser model grid is presented.\\u000a Geologic heterogeneity of an alluvial fan system was characterized using transition-probability-based geostatistical simulations\\u000a of hydrofacies distributions. For comparison of different hydrofacies architecture, two alternative models with different\\u000a hydrofacies structures and geometries and a multi-Gaussian model, all with

Jan H. Fleckenstein; Graham E. Fogg

2008-01-01

273

Near-decadal changes in nitrate and pesticide concentrations in the South Platte River alluvial aquifer, 1993-2004.  

PubMed

The lower South Platte River basin of Colorado and Nebraska is an area of intense agriculture supported by surface-water diversions from the river and ground-water pumping from a valley-fill alluvial aquifer. Two well networks consisting of 45 wells installed in the South Platte alluvial aquifer were sampled in the early 1990s and again in the early 2000s to examine near-decadal ground-water quality changes in irrigated agricultural areas. Ground-water age generally increases and dissolved-oxygen content decreases with distance along flow paths and with depth below the water table, and denitrification is an important natural mitigation mechanism for nitrate in downgradient areas. Ground-water travel time from upland areas to the river ranges from 12 to 31 yr on the basis of apparent ground-water ages. Ground-water nitrate concentrations for agricultural land-use wells increased significantly for oxidized samples over the decade, and nitrogen isotope ratios for oxidized samples indicate synthetic fertilizer as the predominant nitrate source. Ground-water concentrations of atrazine, DEA, and prometon decreased significantly. The decrease in pesticide concentrations and a significant increase in the ratio of DEA to atrazine suggest decreases in pesticide concentrations are likely caused by local decreases in application rates and/or degradation processes and that atrazine degradation is promoted by oxidizing conditions. The difference between results for oxidizing and nitrate-reducing conditions indicates redox state is an important variable to consider when evaluating ground-water quality trends for redox-sensitive constituents such as nitrate and pesticides in the South Platte alluvial aquifer. PMID:18765774

Paschke, Suzanne S; Schaffrath, Keelin R; Mashburn, Shana L

274

Sedimentation and chemical quality of surface waters in the Wind River basin, Wyoming  

USGS Publications Warehouse

This report gives results of an investigation by the U. S. Geological Survey of chemical quality of surface waters and sedimentation in the Wind River Basin, Wyo. The sedimentation study was begun in 1946 to determine the quantity of sediment that is transported by the streams in the basin; the probable sources of the sediment; the effect of large irrigation projects on sediment yield, particularly along Fivemile Creek; and the probable specific weight of the sediment when initially deposited in a reservoir. The study of the chemical quality of the water was begun in 1945 to obtain information on the sources, nature, and amounts of dissolved material that is transported by streams and on the suitability of the waters for different uses. Phases of geology and hydrology pertinent to the sedimentation and chemical quality were studied. Results of the investigation through September 30, 1952, and some special studies that were made during the 1953 and 1954 water years are reported. The rocks in the Wind River Basin are granite, schist, and gneiss of Precambrian age and a thick series of sedimentary strata that range in age from Cambrian to Recent. Rocks of Precambrian and Paleozoic age are confined to the mountains, rocks of Mesozoic age crop out along the flank of the Wind River and Owl Creek Mountains and in denuded anticlines in the floor of the basin, and rocks of Tertiary age cover the greater part of the floor of the basin. Deposits of debris from glaciers are in the mountains, and remnants of gravel-capped terraces of Pleistocene age are on the floor of the basin. The lateral extent and depth of alluvial deposits of Recent age along all the streams are highly variable. The climate of the floor of the basin is arid. The foothills probably receive a greater amount of intense rainfall than the areas at lower altitudes. Most precipitation in the Wind River Mountains falls as snow. The foothill sections, in general, are transitional zones between the cold, humid climate of the high mountains and the warmer, drier climate of the basin floor. Average annual runoff in the basin is about 3.6 inches on the basis of adjusted streamflow records for the Bighorn River near Thermopolis. Runoff from the mountains is high and is mostly from melting of snow and from spring and early summer rains. It does not vary greatly from year to year because annual water losses are small in comparison to annual precipitation. In the areas on the floor of the basin, where runoff is low, the runoff is mostly the result of storms in late spring and early summer. The annual water losses nearly equal the annual precipitation; therefore, runoff is extremely variable, in terms of percentage changes, from year to year and from point to point during any 1 year.

Colby, B. R.; Hembree, C. H.; Rainwater, F. H.

1956-01-01

275

Convex bar formation in an alluvial-bedrock stream channel  

NASA Astrophysics Data System (ADS)

Bar formation in the Guadalupe River occurs at a variety of spatial and temporal scales. The Guadalupe River is a mixed alluvial-bedrock river in central Texas which is characterized by the presence of an alluvial macro channel and a bedrock active channel that is shallowly incised. The flow regime in the Guadalupe and other rivers in the Balcones Escarpment region are punctuated by frequent high-magnitude flooding. The combination of low infiltration capacity upland soils, steep highly dissected watersheds, and dryland vegetation, creates conditions for rapid runoff and large volume sediment loads during floods. The processes controlling bar formation in the Guadalupe River are unlike those in alluvial rivers and is dominated by the process of convex bar formation. Convex bar formation has been documented in a large width to depth ratio river in eastern Wyoming where large volumes of sediment were deposited during floods and then re-worked by the active channel scale longitudinal processes at lower flows. This poster illustrates convex bar formation in the Guadalupe River at the macro and active channel scales as part of the hierarchical classification of channel boundary type in mixed rivers.

Keen-Zebert, A.; Curran, J. C.

2006-12-01

276

Alluvial plains and earthquake recurrence at the Coalinga anticline  

SciTech Connect

Having approached 0.5 m during the May 2 earthquake, the uplift of Quaternary deposits on the Coalinga anticline may provide evidence of the average repeat time of similar earthquakes during the recent geologic past. Stein and King (1984) estimated the average late Quaternary repeat time to be 500 to 1,500 yr from the degree of folding in the upper Pliocene and Pleistocene Tulare Formation; in addition, they estimated the average Holocene repeat time to be at least 200 to 600 yr on the basis of an alluvial-plain profile near Los Gatos Creek, whose arroyo extends across the Coalinga anticline from the synclinal Pleasant Valley into the synclinal San Joaquin Valley. In this chapter, the authors estimate an average repeat time from the stratigraphy of Holocene alluvium exposed in the walls of that arroyo. Largely deposited overbank, this alluvium reveals the approximate configuration of former alluvial plains whose present configuration over the anticline should reflect the rate of anticlinal growth. Resulting constraints on the Holocene uplift rate, though made uncertain by possible differences in the initial configuration of the alluvial plains, suggest an average repeat time of at least 200 to 1,000 yr for major (M = 6-7) Coalinga-area earthquakes during the late Holocene.

Tucker, A.B. (San Jose State Univ., CA (USA)); Donahue, D.J.; Jull, A.J.T (Univ. of Arizona, Tucson (USA)); Payen, L.A. (Univ. of California, Riverside (USA)); Atwater, B.F.; Trumm, D.A.; Tinsley, J.C. III; Stein, R.S.

1990-01-01

277

Petrology of the Middle Run Formation (Precambrian), East Continent Rift Basin, western Ohio and north-central Kentucky  

SciTech Connect

Non-marine sandstones and shales of the Middle Run Formation comprise the known sedimentary fill of the East Continent Rift Basin (ECRB) in the subsurface of western Ohio, Kentucky, and Indiana. The Middle Run Formation is unconformably overlain by the Cambrian Mt. Simon Sandstone, and in two wells is directly overlain by Proterozoic mafic volcanics. Middle Run clastics were examined to determine depositional setting, framework grain composition, provenance, and the basin's hydrocarbon reservoir and source potential. Middle Run sandstones are red to gray, fine to medium-grained, and thickly bedded. The Middle Run Formation is sandstone-dominated, with shales and siltstones forming less than 10% of the unit. Sandstones were deposited in an arid continental setting, in a distal alluvial fan environment. Framework grain compositions of 21 Middle Run sandstones were determined by point counting, and most are immature lithic arenites. Lithics are composed primarily of felsic volcanic rock fragments, with minor mafic volcanics, intraclasts, and metamorphic rock fragments. Provenance is interpreted to consist of both plutonic and extrusive igneous terranes, with some intrabasinal volcanics represented. The adjacent Granite-Rhyolite Province contains rocks of suitable composition to have been a source for Middle Run clastics. Middle Run sandstones are compositionally and diagenetically distinct from the overlying Mt. Simon Sandstone. A complex history of cementation and compaction occluded all primary porosity before deposition of the Mt. Simon. Grain replacement is common, but secondary porosity development is insignificant and no intervals with porosity suitable for hydrocarbon accumulation have been encountered. Potential hydrocarbon source rocks have not been penetrated in wells drilled to date.

Harris, D.C. (Univ. of Kentucky, Lexington, KY (United States))

1992-01-01

278

A conjunctive use hydrologic model for a semi-arid region with irrigated agriculture  

Microsoft Academic Search

A GIS-based sub-basin scale conjunctive use (CU) model is developed for a semi-arid agricultural area in the southern San Joaquin Valley, California. The study area is 2230 square kilometers, and consists of 9114 individual landuse units and 26 water service districts. The CU model consists of three sub-models: 1) a surface water supply (SWS) model, 2) an unsaturated zone water

N. C. Ruud; T. Harter

2003-01-01

279

Late Eocene sea retreat from the Tarim Basin (West China) linked to Asian aridification and Mediterranean Tethys  

NASA Astrophysics Data System (ADS)

The Paleogene sediments of the southwest Tarim Basin along the West Kunlun Shan in western China include the latest remnants of the easternmost extent of an epicontinental sea. It has been suggested that this sea used to extend across the Paleogene Eurasian continent and may have been linked to the Mediterranean Tethys before it separated as the Paratethys. However, the cause and paleoenvironmental impacts of this sea retreat remain elusive because of its still loosely constrained age. The regression has been associated to regional tectonics of the Indo-Asia collision or to global eustatic lowering during the initiation of Antarctic glaciation at the Eocene-Oligocene transition (EOT) 34 million years ago. Also, paleoenvironmental data is lacking to test climate model suggesting that the contribution of the sea retreat to aridification of Asian continental interiors and monsoon intensification is potentially as important as Tibetan plateau uplift. In this study, bio- and magnetostratigraphic results from two sections recording the final marine regression out of the Tarim Basin are presented, providing a framework to reconstruct the role of the sea retreat with respect to global and regional climate. The regression is expressed by a transition from marine greenish clastic limestones to continental alluvial red beds. A rich biostratigraphic assemblage is recovered from the marine sediments including calcareous nannofossils, bivalves, dinoflagellate cysts, benthic foraminifera and ostracods. The microfossil associations indicate a shallow, saline, eutrophic and proximal depositional environment near a strongly arid continental catchment area. The last marine sediments are not younger than mid-Priabonian, whereas polarity pattern recognition in the directly overlying continental red-beds indicate a late Priabonian to Rupelian correlation. Chronostratigraphic synthesis of the bio- and magnetostratigraphic results thus reveal a major hiatus and indicate the long-term eustatic sea-level fall of the late Eocene led to the final retreat of the sea. As suggested by climate models, a late Eocene sea retreat may be linked to coeval aridification of the Asian interior expressed by other regional paleoenvironental records. Additionally, the strong correspondence of the dinoflagellate cysts recovered from the Paleogene sections of the Tarim Basin with records from the Western Tethys shows well-established connections existed between the Mediterranean Tethys and the basins of the Eurasian platform, which confirms the sea that covered the Tarim Basin during the Paleogene did belong to the Tethyan realm and the Paratethys had not yet separated in late Eocene time.

Bosboom, Roderic; Houben, Sander; Dupont-Nivet, Guillaume; Brinkhuis, Henk; Villa, Giuliana; Mandic, Oleg; Stoica, Marius; Krijgsman, Wout; Zhaojie, Guo; Chuanxin, Li

2010-05-01

280

Precipitation and nitrogen interactions in arid ecosystems  

Technology Transfer Automated Retrieval System (TEKTRAN)

Arid and semi-arid ecosystems are among the most impoverished terrestrial systems in terms of water and nitrogen (N) availability. Productivity (NPP) is generally low, soil N pools are small and N loss through percolation is assumed to be negligible. Increased water availability can stimulate both N...

281

Competing Interests and Concerns in the Rio Grande Basin: Mountain Hydrology, Desert Ecology, Climate Change, and Population Growth  

Microsoft Academic Search

In the mountainous American Southwest, the Rio Grande basin is a prime example of how conflicts, misconceptions, and competition regarding water can arise in arid and semi-arid catchments. Much of the Rio Grande runoff originates from snow fields in the San Juan Mountains of southern Colorado and the Sangre De Cristo Mountains of northern New Mexico, far from population centers.

A. Rango

2004-01-01

282

COMPETING INTERESTS AND CONCERNS IN THE RIO GRANDE BASIN: MOUNTAIN HYDROLOGY, DESERT ECOLOGY, CLIMATE CHANGE, AND POPULATION GROWTH  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the mountainous American Southwest, the Rio Grande basin is a prime example of how conflicts, misconceptions, and competition regarding water can arise in arid and semi-arid catchments. Much of the Rio Grande runoff originates from snow fields in the San Juan Mountains of southern Colorado and th...

283

Fire, Holocene Climate Change, and Geomorphic Response Recorded in Alluvial Fan Sediments  

Microsoft Academic Search

Alluvial fan stratigraphic sequences record fire history in charcoal-rich deposits and buried burned soil surfaces. Deposit characteristics provide information about the magnitude of fire-related sedimentation events and severity of associated fires, and radiocarbon-dating of charcoal establishes the timing of fires. Unlike lakes, alluvial fans are ubiquitous in mountain environments. Although alluvial-fan fire records lack the annual resolution of tree-ring records,

J. L. Pierce; G. A. Meyer

2004-01-01

284

Using major ions and ?15N-NO3(-) to identify nitrate sources and fate in an alluvial aquifer of the Baiyangdian lake watershed, North China Plain.  

PubMed

In semi-arid regions, most human activities occur in alluvial fan areas; however, NO3(-) pollution has greatly threatened the shallow groundwater quality. In this paper, ?(15)N-NO3(-) and multi-tracers were used to identify the origin and fate of NO3(-) in groundwater of the Baiyangdian lake watershed, North China Plain. The investigation was conducted in two typical regions: one is the agricultural area located in the upstream of the watershed and another is the region influenced by urban wastewater in the downstream of the watershed. Results indicate that the high NO3(-) concentrations of the upstream shallow groundwater were sourced from fertilizer and manure or sewage leakage, whilst the mixture and denitrification caused the decrease in the NO3(-) concentration along the flow path of the groundwater. In the downstream, industrial and domestic effluent has a great impact on groundwater quality. The contaminated rivers contributed from 45% to 76% of the total recharge to the groundwater within a distance of 40 m from the river. The mixture fraction of the wastewater declined with the increasing distance away from the river. However, groundwater with NO3(-) concentrations larger than 20 mg l(-1) was only distributed in areas near to the polluted river or the sewage irrigation area. It is revealed that the frontier and depression regions of an alluvial fan in a lake watershed with abundant organics, silt and clay sediments have suitable conditions for denitrification in the downstream. PMID:23743546

Wang, Shiqin; Tang, Changyuan; Song, Xianfang; Yuan, Ruiqiang; Wang, Qinxue; Zhang, Yinghua

2013-06-07

285

Attributes of an alluvial river and their relation to water policy and management  

PubMed Central

Rivers around the world are being regulated by dams to accommodate the needs of a rapidly growing global population. These regulatory efforts usually oppose the natural tendency of rivers to flood, move sediment, and migrate. Although an economic benefit, river regulation has come at unforeseen and unevaluated cumulative ecological costs. Historic and contemporary approaches to remedy environmental losses have largely ignored hydrologic, geomorphic, and biotic processes that form and maintain healthy alluvial river ecosystems. Several commonly known concepts that govern how alluvial channels work have been compiled into a set of “attributes” for alluvial river integrity. These attributes provide a minimum checklist of critical geomorphic and ecological processes derived from field observation and experimentation, a set of hypotheses to chart and evaluate strategies for restoring and preserving alluvial river ecosystems. They can guide how to (i) restore alluvial processes below an existing dam without necessarily resorting to extreme measures such as demolishing one, and (ii) preserve alluvial river integrity below proposed dams. Once altered by dam construction, a regulated alluvial river will never function as before. But a scaled-down morphology could retain much of a river's original integrity if key processes addressed in the attributes are explicitly provided. Although such a restoration strategy is an experiment, it may be the most practical solution for recovering regulated alluvial river ecosystems and the species that inhabit them. Preservation or restoration of the alluvial river attributes is a logical policy direction for river management in the future.

Trush, William J.; McBain, Scott M.; Leopold, Luna B.

2000-01-01

286

OSL dating without sand lenses: Late Pleistocene alluvial fan aggradation in the Lost River Range, Idaho  

NASA Astrophysics Data System (ADS)

Along the western front of the Lost River Range (LRR) in Idaho, USA, numerous sheetflood-dominated alluvial fans extend 2-6 km from the mountain front. Despite their geomorphic significance within the basin, these fans are largely inactive under modern conditions and are hypothesized to be remnants of glacial climate (e.g. Pierce and Scott, 1982). To investigate climate and glaciation as potential drivers of fan aggradation, the first goal of this study was determining how best to apply optically stimulated luminescence (OSL) dating as deposits lacked sand lenses and were predominately clast-supported sheetflood gravels with a sandy matrix. The second goal of the study was to investigate the Quaternary climate conditions that promote alluvial fan aggradation, including the importance of glacial activity vs. general glacial climate conditions as drivers of sedimentation. Five fans that represent the variation in late Pleistocene glaciation within contributing basins (0-80% of basin area) were selected for dating and geomorphic mapping. Samples for OSL dating were largely collected by excavating material from under light-safe tarps or at night, with samples for equivalent dose estimates sieved to retain the <2mm portion. Sediment chemistry for dose rate (DR) estimation was analyzed for numerous grain sizes. Sand grain size fractions (<2 mm and 0.15-2.0 mm) produced the highest DR estimates, pebbles (>5 mm) the lowest, with results from bulk samples generally in between. Bulk sample DR estimates were preferred, likely providing the best estimate of the average dose from the sediment. Partial bleaching is not suggested by equivalent dose distributions, but overdispersion values of >20% for some samples may result from the heterogeneity in the sediment DR. Despite potential DR problems, resulting ages are consistent with fan morphology and multiple ages from single surfaces show good agreement. Ages from 31 OSL samples ranged from ~4-60 ka and with mapped fan surfaces suggest aggradation during four distinct intervals: 0-10 ka, 10-20 ka, 20-35 ka and 35-60 ka. Surprisingly, the timing of deposition is similar for all fans, regardless of past glacial extent within contributing basins. The majority of fan aggradation occurred during the late Pleistocene, with deposition during the Holocene limited to ~10% of total fan surface area. The greater extent of late Pleistocene surfaces, steeper slopes and dominance of coarser sheetflood facies suggests greater transport capacity of streams and sediment delivery to fans between 10-60 ka. Regional climate records indicate generally cold climate in the LRR throughout 10-60 ka, but more variable moisture delivery. Cold conditions may have increased transport capacity with greater effective moisture and higher spring discharges in response to increased winter snowpacks . Concurrently, sediment delivery may have increased by mobilization of stored hillslope sediment, decreased vegetation cover or increased sediment production by glaciation, enhanced weathering rates and more effective frost weathering. Overall, this research shows that glacial climate conditions, not necessarily glaciation, enhance hillslope sediment supply and fan aggradation in the LRR of Idaho.

Kenworthy, M.; Rittenour, T. M.; Pierce, J. L.

2011-12-01

287

Provenance and basin evolution, Zhada basin, southwestern Tibet  

NASA Astrophysics Data System (ADS)

The Zhada basin is a late Miocene - Pliocene intermontane basin situated at high elevations in the Himalayan hinterland. The fluvial and lacustrine sediments of the Zhada formation are undeformed and sit in angular unconformity above the deformed Tethyan Sedimentary Sequence (TSS). The basin sits just south of the Indus suture in a structural position occupied elsewhere in the Himalayan orogen by some of the highest mountains on earth, including Everest. The occurrence of a basin at this location demands explanation. Currently, the Sutlej River flows parallel to the structural grain of the Himalaya, westward through the basin, towards the Leo Pargil (Qusum) range. Near the range front it takes a sharp southward turn, cuts across the structural grain of the Himalaya and out into the Gangetic foreland. Palaeocurrent indicators in the lower part of the Zhada formation show that the basin originated as a northwest flowing axial river. Palaeocurrent indicators are consistently northwest oriented, even to within to within 10 km of the Leo Pargil range front in the north-western end of the basin. This implies that at the onset of sedimentation in Zhada basin the Leo Pargil range was not a barrier as it is today. In the upper part of the Zhada formation, palaeocurrent indicators are generally directed towards the centre of the basin. In the central and southern portions of the basin this indicates a transition from an axial, northwest flowing river to prograding fluvial and alluvial fans. However, in the north-western part of the basin the change between lower and upper Zhada formation involves a complete drainage reversal. This change in palaeocurrent orientation is also reflected in the detrital zircon signal from basin sediments. Low in the Zhada formation the detrital zircon signal is dominated by zircons from the Kailash (Gangdese) batholith (or associated extrusives, see below). However, higher in the sections, a local source, either from the TSS or the core of the Leo Pargil range dominates the detrital zircon signal. Finally, there is a shift in the sandstone composition from unmetamorphosed sedimentary lithic fragments and extrusive felsic volcanic fragments in the lower part of the Zhada formation to metasedimentary and metaigneous fragments in the upper part of the Zhada formation. This is likely linked either to unroofing of the source terrain or a change to another source terrain. Based on the palaeocurrent and detrital zircon data, a change to another source terrain is favoured. This combination of evidence suggests that the Zhada basin evolved from a through-going fluvial plain to a dammed lake primarily due to uplift of the Leo Pargil range. This uplift would have dammed and ponded the river, and exposed higher grade metamorphic rocks at the surface for incorporation into Zhada formation sandstones. It also would have introduced a new source for detrital zircons. Uplift of the Leo Pargil range along a low angle normal fault would also have evacuated portions of the mid-crust, providing a mechanism for subsidence in the Zhada region. Lacustrine sedimentation would have coincided with progradation of marginal alluvial fans and would have continued until the basin was filled in to the level of a new spill point. At this time incision and re- establishment of the Sutlej River would have occurred.

Saylor, J.; Decelles, P.; Gehrels, G.; Kapp, P.

2007-12-01

288

Groundwater vulnerability map for the Ebro alluvial aquifer between Jalón and Ginel tributaries (Spain)  

NASA Astrophysics Data System (ADS)

The Quaternary deposits of the Ebro Basin in the surroundings of Zaragoza (Spain) form an unconfined alluvial aquifer with a high degree of permeability and low thickness of unsaturated materials. This fact causes a high degree of vulnerability to contamination, which implies consequences for land-use decisions and the risk management of existing industrial facilities. In addition, in the last decades the intense irrigation and the use of pesticides is threatening the quality of the groundwater and as a consequence the amount of usable groundwater at a low cost. Thus, the development of groundwater vulnerability maps has great importance in a regional planning process. Consequently, groundwater vulnerability maps have been developed following a method proposed by the German State Geological Surveys. In this paper the methodology developed within ArcGIS and Gocad, a two- and three-dimensional software, respectively, is presented. Although the results obtained within GIS (Geographical Information System) are acceptable it is to say that the 3D-model improves considerably the final product.

Lamelas, M. T.; Marinoni, O.; Hoppe, A.; de La Riva, J.

2007-12-01

289

Elevated Mercury Concentrations in Alluvial Deposits of the Humid Tropics of South America: Natural vs. Anthropogenic Sources  

NASA Astrophysics Data System (ADS)

Mercury (Hg) amalgamation is extensively used throughout the humid tropics of South America for the extraction of fine-gold particles from secondary ore deposits. Early studies of water, sediments and fish generally concluded that these gold mining operations have extensively contaminated the aquatic environment. However, investigations along a 900-km reach of the Maderia River, Brazil suggest that while Hg values in sediments and water are above global averages, the high mercury levels are largely due to natural sources. Of primary significance is the inability to distinguish between Hg concentrations in upland soils (oxisols) and modern channel and floodplain deposits. Spatial trends in the data suggest that the impact of anthropogenically released Hg from mine sites is relatively localized. This conclusion is supported by other, independent studies in the Rio Negro basin where elevated Hg values were found in terrace deposits in spite of the fact that no modern mining activities are known to occur within the watershed. Moreover, Roulet and his colleagues have demonstrated using mass balance calculations that within the Tapajos River basin as much as 97 percent of Hg in the alluvial deposits is derived from Hg enriched oxisols eroded during deforestation. In a regional examination of Hg levels within alluvial deposits of Essequibo and Mazaruni Rivers of Guyana, we again found that Hg levels were above both regional background values (10 to 80 ppb) and global averages. However, deforestation within these watersheds is limited, reducing the influx of Hg from eroded upland soils. In addition, the spatial trends in Hg concentrations suggest a closer link between mining activities and Hg values than is found in Maderia River of Brazil. It is unclear at this time, however, whether the primary Hg source in Guyana is the direct input of Hg to the river during amalgamation, or to the influx of Hg enriched soils eroded during the dredging of channel bed sediments and hydraulic mining of floodplain materials.

Miller, J. R.; Lechler, P. J.

2001-12-01

290

Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China  

NASA Astrophysics Data System (ADS)

Increasing water scarcity places considerable importance on the quantification of water footprint (WF) at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB), a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr-1 in the HRB over 2004-2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production). The remaining 4% was for the industrial and domestic sectors. The "blue" component of WF was 811 million m3 yr-1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than green WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.

Zeng, Z.; Liu, J.; Koeneman, P. H.; Zarate, E.; Hoekstra, A. Y.

2012-05-01

291

Remote sensing classification of the arid watersheds of Iran  

NASA Astrophysics Data System (ADS)

Iran's most obvious hydroclimatic problems are compounded of the disadvantages of scanty and highly seasonal precipitation and a surface configuration which tends to concentrate moisture on the periphery of the country, leaving its vast heart an area of irreconcilable sterility. Most of the central Iran has arid conditions with dry and hot summer months, when streams with and the land is parched. Nowhere in Iran is there an annual surplus of water, and significant seasonal surpluses occur in only the wishbone of high mountains that encloses the central plateau on the north and west. In most parts (about 80 percent of the total of country) the nature of human activity depends upon the availability of surface water that can be tapped by wells and qantas. Runoff is episodic and occurs only because the precipitation, meagre as it is momentarily exceeds the infiltration capability of the surface. Such precipitation is not of course capricious in terms of quantity, location and distribution in time. For more accurate investigation, remote sensing data was used to overcome the large area. Finally for arid basins, combined data from remote sensing (Cosmos and Aerial photographs) data and topography maps provided significant results.

Solaimani, Karim; Habibnejad-Roshan, Mahmud

2002-01-01

292

Alluvial Diamond Resource Potential and Production Capacity Assessment of Ghana  

USGS Publications Warehouse

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by both diamond-producing and diamond-importing countries. Over 70 countries were included as members at the end of 2007. To prevent trade in 'conflict' diamonds while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was to assess the alluvial diamond resource endowment and current production capacity of the alluvial diamond-mining sector in Ghana. A modified volume and grade methodology was used to estimate the remaining diamond reserves within the Birim and Bonsa diamond fields. The production capacity of the sector was estimated using a formulaic expression of the number of workers reported in the sector, their productivity, and the average grade of deposits mined. This study estimates that there are approximately 91,600,000 carats of alluvial diamonds remaining in both the Birim and Bonsa diamond fields: 89,000,000 carats in the Birim and 2,600,000 carats in the Bonsa. Production capacity is calculated to be 765,000 carats per year, based on the formula used and available data on the number of workers and worker productivity. Annual production is highly dependent on the international diamond market and prices, the numbers of seasonal workers actively mining in the sector, and environmental conditions, which influence seasonal farming.

Chirico, Peter G.; Malpeli, Katherine C.; Anum, Solomon; Phillips, Emily C.

2010-01-01

293

Lignin Degradation and Humus Formation in Alluvial Soils and Sediments  

PubMed Central

The contribution of lignin to the formation of humic compounds was examined in different environments of the terrestrial-aquatic interface in the Garonne River valley in southwestern France. Alluvial soils and submerged or nonsubmerged river and pond sediments containing alder, poplar, or willow [14C-lignin]ligno-celluloses were incubated. After a 49-day incubation period, 10 to 15% of labeled lignins in alluvial soils was recovered as evolved 14CO2. In nonsubmerged sediments, 10% of the applied activity was released as 14CO2, and in submerged sediments, only 5% was released after 60 days of incubation. In the different alluvial soils and sediments, the bulk of residual activity (70 to 85%) remained in the two coarsest-grain fractions (2,000 to 100 and 100 to 50 ?m). Only 2 to 6% of the residual activity of these two coarse fractions was recovered as humic and fulvic acids, except in the case of alder [14C-lignin]lignocellulose, which had decomposed in a soil collected beneath alders. In this one 55% of the residual activity was extracted as humic substances from the 2,000- to 100-?m fraction. Humic and fulvic acids represented from 6 to 50% of the residual activity in the finest-grain fractions (50 to 20 and 20 to 0 ?m). The highest percentages were obtained in soil collected beneath alders and in submerged pond sediment. The contribution of different groups of microorganisms, as well as nutrients and clay content, may influence humic-substance formation in such environments. Physical stability also may be an important factor for complex microbial activity involved in this process.

Fustec, Eliane; Chauvet, Eric; Gas, Gilbert

1989-01-01

294

The migration, dissolution, and fate of chlorinated solvents in the urbanized alluvial valleys of the southwestern USA  

NASA Astrophysics Data System (ADS)

The migration, dissolution, and subsequent fate of spilled chlorinated solvents in the urban alluvial valleys of the southwestern U.S. appear to be governed by a unique set of hydrogeologic and geochemical processes occurring within terrigeneous clastic depositional systems. The alluvial and lacustrine fill of the basins, the trapping of solvents in fine-grained sediments beneath the urbanized valley centers, the oxic conditions typical of the deeper alluvium, and the contaminant-transport patterns produced by large-scale basin pumping combine to produce long aqueous-phase plumes derived from the dissolution of trapped chlorinated solvents. Although of limited aqueous solubility, these dense solvents are sufficiently mobile and soluble in the southwestern alluvial valleys to have produced aqueous plumes that have migrated several kilometers through the deeper alluvium and have contaminated valuable water-supply well fields in California, Arizona, and New Mexico. The typical length of these plumes and the presence of oxic groundwater indicate that it is unlikely that natural attenuation will be a practical remedial option in the southwestern alluvial valleys or in other alluvial systems in which similar hydrogeologic and geochemical conditions exist. Résumé La migration, la dissolution et l'évolution consécutive des rejets de solvants chlorés dans les vallées alluviales du sud-ouest des États-Unis paraissent déterminées par un même ensemble de processus hydrogéologiques et géochimiques intervenant dans des formations de dépôts clastiques terrigènes. Les remplissages alluviaux et lacustres des bassins, le piégeage des solvants par des sédiments fins sous les centres des vallées urbanisées, les conditions oxiques typiques des alluvions plus profondes et les types de transport de contaminants provoqués par le pompage à l'échelle du bassin se combinent pour produire des panaches, étendus dans la phase aqueuse, provenant de la dissolution de solvants chlorés piégés. Malgré leur faible solubilité dans l'eau, ces solvants denses sont suffisamment mobiles et solubles pour avoir produit, dans le sud-ouest des vallées alluviales, des panaches aqueux qui ont migré de plusieurs kilomètres dans les alluvions plus profondes et ont contaminé des champs captants pour l'eau potable en Californie, en Arizona et au Nouveau-Mexique. La longueur de ces panaches et la présence d'eau souterraine en conditions oxiques indiquent qu'il est peu probable que la décroissance naturelle soit un recours pratique de décontamination dans les vallées alluviales du sud-ouest ou dans d'autres systèmes alluviaux dans lesquels existent des conditions hydrogéologiques et géochimiques semblables. Resumen La migración, disolución y transporte de compuestos clorados en valles aluviales urbanos del sudoeste de los Estados Unidos de América parecen estar gobernados por un conjunto único de procesos hidrogeológicos y geoquímicos que tienen lugar en los depósitos clásticos. El relleno aluvial y lacustre de las cuencas, la inmovilización de los solutos en sedimentos de grano fino bajo las zonas urbanizadas, los condiciones óxicas típicas del aluvial profundo y las direcciones de transporte regidas por los fuertes bombeos en las cuencas se combinan para producir grandes penachos en fase acuosa procedentes de la disolución de los compuestos clorados atrapados en el medio. Aunque la solubilidad de estos compuestos clorados densos es pequeña, es suficiente para producir penachos que en algunos casos se han desplazado varios kilómetros a través del aluvial profundo y han llegado a contaminar zonas de extracción muy productivas en California, Arizona y Nuevo México. La longitud de estos penachos y la presencia de agua subterránea oxidante indican que es improbable que la degradación natural sea un buen método de limpieza de estos acuíferos o de otros sistemas aluviales que presenten características hidrogeológicas y geoquímicas semejantes.

Jackson, R. E.

295

Tectonics of west central New Mexico and adjacent Arizona: a remote sensing and field study in arid and semi-arid areas  

SciTech Connect

Large-scale fault zones in west-central New Mexico and eastern Arizona were mapped using conventional fieldwork aided by Landsat and Seasat images and high altitude air photos. These faults, which are of post-early Miocene age, trend NE-SW and N-S and extend over 200 km. The fault zones bound very large horst and graben blocks which, although located on the physiographic Colorado Plateau, are characteristic of Basin and Range deformation. Their intersection has been the locus of extensive Cenozoic volcanism. The procedure developed in this project permitted investigation of an area of about 1.8 x 10/sup 5/ km/sup 2/ of arid and semi-arid land whose structures previously were poorly defined.

Baldridge, W.S.; Bartov, Y.; Kron, A.

1981-01-01

296

Are North Slope surface alluvial fans pre-Holocene relicts?  

USGS Publications Warehouse

The surface morphology of the northern slope of the Brooks Range (North Slope) from the Canning River, Alaska, eastward is dominated by a series of large alluvial fans and braided streams floored by coarse alluvium. On the basis of our studies, we conclude that the fans are not prograding now nor have they been prograding at any time during the Holocene. During the latest transgression and the following sea-level highstand, the North Slope depositional environment and climate probably differed greatly from the present ones.

Reimnitz, Erk; Wolf, Stephen C.

1998-01-01

297

Water and the arid lands of the western United States  

SciTech Connect

The United States is water-rich, but conflicts over water development and use are increasing. Today, economic scarcity - not absolute physical scarcity - is the key issue in many places. In the arid American West, traditionally over 90 percent of the water consumed has been used to irrigate agriculture. But as cities grow and the states's economies diversify, municipal, commercial, and industrial uses exert more pressure. At the same time, groundwater mining and water quality degradation are becoming commonplace. The challenge is to increase productivity while equitably distributing the costs and benefits of water use. This book includes three case studies that cover primarily agricultural areas (the Central Valley of California, the High Plains of Texas, and the upper Colorado River basin) and three on the problems of metropolitan areas (Denver, Tucson, and the southern California megalopolis). The authors also identify policies that could help the West sustain economic growth without destroying or undervaluing its natural resources.

El-Ashry, M.T.; Gibbons, D.C.

1988-01-01

298

Rivers turned to rock: Late Quaternary alluvial induration influencing the behaviour and morphology of an anabranching river in the Australian monsoon tropics  

NASA Astrophysics Data System (ADS)

Late Quaternary alluvial induration has greatly influenced contemporary channel morphology on the anabranching Gilbert River in the monsoon tropics of the Gulf of Carpentaria. The Gilbert, one of a number of rivers in this region, has contributed to an extensive system of coalescing low-gradient and partly indurated riverine plains. Extensive channel sands were deposited by enhanced flow conditions during marine oxygen isotope (OI) Stage 5. Subsequent flow declined, probably associated with increased aridity, however, enhanced runoff recurred again in OI Stages 4 3 (˜65 50 ka). Aridity then capped these plains with 4 7 m of mud. A widespread network of sandy distributary channels was incised into this muddy surface from sometime after the Last Glacial Maximum (LGM) to the mid Holocene during a fluvial episode more active than the present but less so than those of OI Stages 5 and 3. This network is still partly active but with channel avulsion and abandonment now occurring largely proximal to the main Gilbert flow path. A tropical climate and reactive catchment lithology have enhanced chemical weathering and lithification of alluvium along the river resulting in the formation of small rapids, waterfalls and inset gorges, features characteristic more of bedrock than alluvial systems. Thermoluminescence (TL) and comparative optically stimulated luminescence (OSL) ages of the sediments are presented along with U/Th ages of pedogenic calcrete and Fe/Mn oxyhydroxide/ oxide accumulations. They show that calcrete precipitated during the Late Quaternary at times similar to those that favoured ferricrete formation, possibly because of an alternating wet dry climate. Intense chemical alteration of the alluvium leading to induration appears to have prevailed for much of the Late Quaternary but, probably due to exceptional dryness, not during the LGM. The result has been restricted channel migration and a reduced capacity for the channel to adjust and accommodate sudden changes in bedload. Consequent avulsions have caused local stream powers to increase by an order of magnitude, inducing knickpoint erosion, local incision and the sudden influx of additional bedload that has triggered further avulsions. The Gilbert River, while less energetic than its Pleistocene ancestors, is clearly an avulsive system, and emphasizes the importance in some tropical rivers of alluvial induration for reinforcing the banks, generating nickpoints, reworking sediment and thereby developing and maintaining an indurated and anabranching river style.

Nanson, Gerald C.; Jones, Brian G.; Price, David M.; Pietsch, Timothy J.

2005-09-01

299

Astronomical forcing of sedimentary cycles in the middle to late Miocene continental Calatayud Basin (NE Spain)  

Microsoft Academic Search

A high-resolution cyclostratigraphic and magnetostratigraphic study was carried out on cyclically bedded successions of middle Miocene lacustrine to distal alluvial fan-floodplain deposits from the Calatayud basin, in northeast Spain. Eight (partially overlapping) subsections near the village of Orera are correlated in detail using distinct sedimentary cycle patterns or by following marker beds in the field. Together they form the Orera

H. Abdul Aziz; F. J. Hilgen; W. Krijgsman; E. Sanz; J. P. Calvo

2000-01-01

300

Near surface water balance in the Northern Murray-Darling Basin  

Microsoft Academic Search

The water balance allows the calculation of deep drainage from other components of the hydrological cycle. Deep drainage has been linked to outbreaks of dryland and irrigated salinity. Until recently, deep drainage was not considered to be an issue on the alluvial plains of the Northern Murray- Darling Basin. Recent simulation studies and calculations using the water balance suggest that

R. W. Vervoort; M. Silburn; M. Kirby

2003-01-01

301

Sedimentology and geochemistry of carbonates from lacustrine sequences in the Madrid Basin, central Spain  

Microsoft Academic Search

Lacustrine and alluvial carbonate facies have been investigated in Middle Miocene successions of the western side of the Madrid Basin in order to evaluate paleoenvironments in which carbonates formed. Carbonate facies are varied and include: (1) calcrete and dolocrete; (2) pond deposits; (3) lake margin dolostone; (4) mudflat carbonate; and (5) open-lake carbonate facies. The dominant mineralogy of these is

J. P. Calvo; B. F. Jones; M. Bustillo; R. Fort; A. M. Alonso Zarza; C. Kendall

1995-01-01

302

Experimental Drainage Basins in Israel: Rainfall, Runoff, Suspended Sediment and Bedload Monitoring  

Microsoft Academic Search

Within the hyper-arid to semiarid areas of Israel three experimental drainage basins varying in area, climate, monitoring duration and type have been being research-monitored. Lessons derived from a large number of published and ongoing research projects on these experimental basins focus on runoff and sediment in drylands. The effect of the spatial distribution of rainfall on runoff generation becomes increasingly

Jonathan Laronne; Judith Lekach; Hai Cohen; Yulia Alexandrov

303

Characterization of the hydrological functioning of the Niger basin using the ISBA-TRIP model  

Microsoft Academic Search

During the 70s and 80s, West Africa has faced extreme climate variations with extended extreme drought conditions. Of particular importance is the Niger basin, since it traverses a large part of the Sahel and is thus a critical source of water in this semi arid region. However, the understanding of the hydrological processes over this basin is currently limited by

V. Pedinotti; A. Boone; B. Decharme; J. F. Crétaux; N. Mognard; G. Panthou; F. Papa

2011-01-01

304

Frequency and Spatial Characteristics of Droughts in the Conchos River Basin, Mexico  

Microsoft Academic Search

The temporal and spatial characteristics of droughts are investigated to provide a framework for sustainable water resources management in a semi-arid region. Using the Palmer Drought Severity Index (PDSI) as an indicator of drought severity, the characteristics of droughts are examined in the Conchos River Basin in Mexico. This basin is important to both the United States and Mexico, because

Tae-Woong Kim; Juan B. Valdés; Javier Aparicio

2002-01-01

305

Overview of Hydrologic Issues in the Upper Klamath River Basin, Oregon  

Microsoft Academic Search

The geologic setting of the upper Klamath Basin makes it a naturally arid landscape with eutrophic water bodies. Anthropogenic alterations of the land and hydrology over the past 100 years have put large demands on water supplies and further enriched water bodies with nutrients. Major changes to the upper basin include diking and draining lakes and wetlands for agricultural and

D. D. Lynch

2005-01-01

306

Agricultural manipulation of floodplains in the southern Basin and Range Province  

Microsoft Academic Search

Floodplains in arid lands can be agriculturally productive, but they can also be geomorphically unstable environments. Many of the floodplains of higher order basins in southern portion of the Basin and Range Province of the American Southwest have been farmed intermittently for hundreds of years, and continuously for the past century. In order to be productive, however, these floodplains were

William E. Doolittle

2006-01-01

307

Vegetation evolution in arid land of western China  

NASA Astrophysics Data System (ADS)

NDVI Normalized Difference Vegetation Index values range from -1.0 to +1.0, areas with NDVI < 0 rarely contain any vegetation, while NDVI >0.6, vegetation cover reaches 100%. The FVC (Fractional Vegetation Cover) values range from 0 to +1.0. Above this threshold the fractional vegetation cover increases approximately as the square of the NDVI, and reaches 100% at an upper NDVI threshold, which is considerably less than 1.0. In arid and semi-arid regions, FVC is superior to NDVI. In this article we got the classification rules by using the resolution 1km FVC combining with DEM (Digital Elevation Model) to classify the vegetation types in arid parts of western China. This classification system was used to classify all FVC images of the resolution 8km*8km from 1982a to 2000a, in this way, we got the classification maps of vegetation for every year. From these classification maps we calculated three majority maps from 1982-1989a, 1990-1995a and 1996-2000a. Supported by software ARC/INFO allowed us to decided wheter cells were degraded or improved after comparing every cell value at same location in three serial maps and then getting the evolution map of vegetation. The main results are as follows: 1) the vegetation in all of arid west China has increased; 2) the vegetation was increased and the rate is higher than in all study area; cells showing improvement in mountainous areas are almost equal to cells showing degradation3) there were two types of improvement patches; the oasis patch increases around old oases and the plain sparse desert patch has also increased; 4) degradation patches appear more frequently in the lower reaches of the Tarim River, in all reaches of Cherchen River, the Jungger basin and to the south of Alxa Right County of Inner Mongolia; 5) in mountainous areas, most of the improvement cells took place in the south of the Tianshan mountains and Pamir high plain, degradation cells are located on the slope of the north Kunlun mountains as a long narrow region and big patch assembled in the Aljin Mountains and the north slope of the Qilian Mountains.

Shi, Qingdong; Lu, Guanhui; Xiao, Jidong; Pan, Xiaoling; Zhang, Jie; Ji, Liang; Chang, Shunli

2003-07-01

308

Catalogue of large alluvial fans in martian impact craters  

NASA Astrophysics Data System (ADS)

We conducted a systematic, global survey using Thermal Emission Imaging System Infrared (THEMIS IR) coverage (˜100 m/pixel) to search for large alluvial fans in impact craters on Mars. Our survey has focused on large fans (apron areas greater than ˜40 km 2, usually located in craters greater than 20 km in diameter) due to the resolution of the THEMIS images and Mars Orbiter Laser Altimeter (MOLA) coverage. We find that the host craters are found to have a distinctive diameter range from 30-150 km. The fans generally cluster in three geographic areas—southern Margaritifer Terra, southwestern Terra Sabaea, and southwestern Tyrrhena Terra, however several outliers do exist. The alluvial fans do not form in a particular orientation along the crater rim nor are they associated with the location of current high rim topography. Fan area magnitude and variability increase with crater diameter while fan concavity magnitude and variability increase with decreasing crater diameter. Smaller fan aprons in general have higher, more variable concavity. The source of the water forming these fans is uncertain given the challenges of accommodating the global distribution pattern and formation patterns within the craters.

Kraal, Erin R.; Asphaug, Erik; Moore, Jeffery M.; Howard, Alan; Bredt, Adam

2008-03-01

309

Mineralogy of lode and alluvial gold from the western Capricorn Orogen, Western Australia  

Microsoft Academic Search

There are significant differences in the mineralogy of lode and alluvial gold from the Egerton Mining Centre (EMC) compared with that of gold from the Bangemall Mining Centre (BMC) in the western Capricorn Orogen of Western Australia. In contrast, within each mining centre, lode and alluvial gold are very similar, with minor differences being due to weathering and transport processes.

E. A. Hancock; A. M. Thorne

2011-01-01

310

Hydrogeochemistry of alluvial groundwaters in an agricultural area: an implication for groundwater contamination susceptibility  

Microsoft Academic Search

Alluvial groundwaters in the area where intensive agricultural activity takes place were geochemically investigated to evaluate factors regulating groundwater quality of alluvial aquifers. For this study, 55 groundwater samples were taken from the uniformly distributed irrigation wells and were classified into three distinct groups according to their geochemical characteristics. This study reveals that the groundwater quality and the geochemical characteristics

Gi-Tak Chae; Kangjoo Kim; Seong-Taek Yun; Kyoung-Ho Kim; Soon-Oh Kim; Byoung-Young Choi; Hyoung-Soo Kim; Chul Woo Rhee

2004-01-01

311

RIVER TRANSPORT - INDUCED CHANGES IN CHEMICAL COMPOSITION OF ALLUVIAL GOLD (DOCUMENTED ON LOCALITIES THE WESTERN CARPATHIANS)  

Microsoft Academic Search

Alluvial gold is influenced by various physical, chemical and biological factors. As type- localities for study of changes in chemical composition of alluvial gold we chose Pukanec (Central Slovakia Neovolcanic Field) and Magurka and Ni?ná Boca (Nízke Tatry Mts). The most distinctive are morphological and chemical changes (dissolution and precipitation), the latter is most commonly represented by the formation of

B. BAHNA; A. SMIRNOV; M. CHOVAN; F. BAKOS

312

Experimental Drainage Basins in Israel  

NASA Astrophysics Data System (ADS)

Within the hyper-arid to semiarid areas of Israel are three experimental drainage basins. They are the Nahal (stream in Hebrew) Yael, subdivided into five sub-basins, Rahaf-Qanna'im (main and tributary, respectively) and Eshtemoa. These basins vary in drainage area and climate, and in monitoring duration and type. All are drained by gravel-bed channels. As the size of monitored drainage area is limited, 3-4 additional representative basins covering areas of 300, 1000, 2000 and 8000 square kilometers will likely be implemented in the next decade. The basins have precipitation, runoff, sediment and fluviomorphological records. Each was conceived for differing purposes, but all share the common two objectives for the continuous monitoring: 1. Many hydrological issues may be approached if, and only if, there are prototype databases on a wide spectrum of hydrological processes; and 2. There is a need for long-term records to assess large floods and subsequent hydrologic and geomorphic recovery. Lessons derived from a large number of research projects on these experimental basins focus on characteristics of runoff in arid climates. For example, the effect of the spatial distribution of rainfall on runoff generation becomes increasingly important with aridity. Rainfall angle on hillslopes and storm intensity and direction derived from rainfall recorders and radar backscatter are crucial for explanation of runoff response. Runoff hydrographs tend to have more bores, shorter-duration peaks, briefer recessions, longer dry periods, and are more variable in terms of flood volume and peaks with increased aridity. Suspended-sediment fluxes, yields and concentrations are relatively large in the semiarid realm, reaching maxima at the beginning of a flood season and after long dry spells. Bedload fluxes are exceptionally high from dryland basins in which hillslopes are minimally vegetated and where bedload transport takes place in channels lacking an armor layer. Bedload/suspended-sediment load ratios increase with aridity. Bedload yield may represent up to 70% of the total load. Hillslope to channel connectivity is high in drylands. In the hyperarid region suspended-sediment sources are hillslopes and the coarser, sandy fraction of the channel bedmaterial. The depth of channel bed activity is indicated by a fluvio-pedogenic unit beneath the channel surface. National and regional hydrological research needs will dictate future global monitoring in experimental basins. International collaboration may bring about considerable cost reduction by exclusion of monitoring aspects that can be evaluated based on the monitoring in other, similar conditions. Advanced international collaboration on validation and calibration of and consistency in monitoring means, as well as syntheses of lessons derived from international collaboration, such as from an International Watershed Research Network, are required for maximizing our understanding of water and sediment responses in varied global regions.

Laronne, J. B.; Lekach, J.; Cohen, H.; Gray, J.

2002-12-01

313

Depositional setting and diagenetic evolution of some Tertiary unconventional reservoir rocks, Uinta Basin, Utah.  

USGS Publications Warehouse

The Douglas Creek Member of the Tertiary Green River Formation underlies much of the Uinta basin, Utah, and contains large volumes of oil and gas trapped in a complex of fractured low-permeability sandstone reservoirs. In the SE part of the basin at Pariette Bench, the Eocene Douglas Creek Member is a thick sequence of fine- grained alluvial sandstone complexly intercalated with lacustrine claystone and carbonate rock. Sediments were deposited in a subsiding intermontane basin along the shallow fluctuating margin of ancient Lake Uinta. Although the Uinta basin has undergone postdepositional uplift and erosion, the deepest cored rocks at Pariette Bench have never been buried more than 3000m.-from Authors

Pitman, J. K.; Fouch, T. D.; Goldhaber, M. B.

1982-01-01

314

Groundwater quality in the lower Varuna River basin, Varanasi district, Uttar Pradesh  

Microsoft Academic Search

The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural\\u000a area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of\\u000a impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting

N. Janardhana Raju; Prahlad Ram; Sangita Dey

2009-01-01

315

Exploration of a Basin and Range-Type Geothermal System Using Soil pH Analysis  

Microsoft Academic Search

The Socorro Peak, NM Known Geothermal Reservoir Area (KGRA) is a Basin and Range-type extentional-fault geothermal system boasting thermal gradients upwards of 420 mW\\/m3 in an uplift Precambrian fault block. Structural and geophysical evidence suggests that a low-to-mid temperature (60-100C) geothermal aquifer may reside within the fault-bounded alluvial basin, capped and insulated by over 1000meters of Tertiary mudstone aquitard strata

L. Owens; G. Hill; D. I. Norman

2005-01-01

316

Hydrogeology, model description, and flow analysis of the Mississippi River alluvial aquifer in northwestern Mississippi  

USGS Publications Warehouse

The Mississippi River alluvial aquifer underlies a 7,000-square-mile area of the Mississippi River alluvial plain in northwestern Mississippi, an area locally known as the Delta. The alluvial aquifer is the most heavily pumped aquifer in Mississippi, and wells yielding more than 2,000 gallons per minute are common. About 98 percent of the pumpage from the alluvial aquifer is for agriculture. The sand and gravel that form the alluvial aquifer averages about 110 feet in thickness. The aquifer is confined over most of the Delta, and the upper confining unit averages about 25 feet in thickness. The average depth to water in the alluvial aquifer during fall 1999 was about 25 feet. The alluvial aquifer receives lateral recharge at the western boundary from the Mississippi River and at the eastern boundary from aquifers that directly underlie the Bluff Hills. The alluvial aquifer receives water vertically from precipitation, internal streams and lakes, and locally from the Cockfield and Sparta aquifers where they directly underlie the alluvial aquifer. The alluvial aquifer also discharges water to the underlying aquifers, and during extended periods with no surface runoff, to the Mississippi River and to the internal streams and lakes. The magnitude of recharge from the Mississippi River, precipitation, and internal lakes and streams can vary greatly depending upon hydrologic and climatic conditions. The U.S. Geological Survey modular threedimensional finite-difference ground-water flow model, MODFLOW, was used to simulate the Mississippi River alluvial aquifer flow system in northwestern Mississippi. The model uses one layer with a rectangular-grid and 1-mile square cells to represent the alluvial aquifer. The model was calibrated and verified by using spring and fall water-level measurements from January 1988 through December 1996. The values of selected model calibration-derived parameters for the alluvial aquifer are hydraulic conductivity, 425 feet per day; specific yield, 0.32; and storage coefficient, 0.016. The model showed that the aquifer lost water from storage at an average rate of 404 cubic feet per second during the 9-year simulation period. During this period, the average pumpage rate was 1,270 million gallons per day (1,980 cubic feet per second). Simulated areal recharge from precipitation averaged 2.6 inches per year (1,360 cubic feet per second). Vertical recharge from the internal streams and lakes and lateral recharge from aquifers underlying the Bluff Hills averaged 113 and 108 cubic feet per second, respectively. Model results indicated that net recharge from the Mississippi River and from aquifers directly underlying the alluvial aquifer was small.

Arthur, J. K.

2001-01-01

317

Institutions and Societal Impacts of Climate in the Lower Colorado and San Pedro Basins of the U.S.Mexico Border Region  

Microsoft Academic Search

The U.S. Southwest and Mexico border region feature two prominent river basins, the Colorado and Rio Grande, and ecologically important sub-basins such as the San Pedro. The area within which these transboundary basins lie is characterized by overall aridity and high climatic variability over seasonal to decadal and longer time scales. Throughout human occupation, numerous and diverse strategies for buffering

R. G. Varady; M. Wilder; B. J. Morehouse; G. M. Garfin

2007-01-01

318

Kinematic Analysis of the Arid Manipulator.  

National Technical Information Service (NTIS)

The kinematic structure of the ARID manipulator lends itself to simple forward and inverse kinematics analysis. The purpose of this paper is to fully document and verify an existing analysis. The symbolic software package MATHEMATICA was used to produce a...

K. L Doty

1992-01-01

319

The role of volcanic activity and climate in alluvial fan growth at volcanic areas: an example from southern Campania (Italy)  

Microsoft Academic Search

Volcaniclastic-rich alluvial fans developed in the southern Campanian Plain (Italy) during the late Pleistocene and Holocene in an area eastward of the Somma-Vesuvius and Campi Flegrei volcanoes. Meanwhile, bedrock-rich alluvial fans developed in areas unaffected by pyroclastic deposition. Late Pleistocene and Holocene volcaniclastic-rich alluvial fans show some important differences: (i) late Pleistocene alluvial fans were dominated by hyperconcentrated flow deposits,

G. Zanchetta; R. Sulpizio; M. A Di Vito

2004-01-01

320

Sediment yield assessment by EPM and PSIAC models using GIS data in semi-arid region  

NASA Astrophysics Data System (ADS)

Among land degradation processes, soil erosion is the most serious threat to soil and water conservation in semi-arid regions. At the present study, the sedimentation hazard and the erosion zonation were investigated at Kardeh watershed, north-east of Iran by Erosion Potential Method (EPM) and Pacific Sonth-west Inter Agency Committee (PSIAC) models, in combination with the geographical information system (GIS) data, satellite data and field observations. According to our investigation the study area can be categorized into heavy, moderate and slight erosion zones with the total sediment yield of 147859 and 148078m3/a estimated by EPM and PSIAC models, respectively. The sub-basins located at the middle and south parts of the watershed are highly eroded due to the geology formation and soil erodibility conditions, while the sub-basins at the north parts are moderately eroded because of the intensive land cover. The amounts of the sediment yield in most areas are found to be consistent between the EPM and PSIAC models ( R 2 = 0.95). Our data suggest the applicability of both empirical models in evaluating the sediment yield in arid and semi-arid watersheds.

Bagherzadeh, Ali; Daneshvar, Mohammad Reza Mansouri

2011-06-01

321

Forecasting Streamflows in the San Juan River Basin in Argentina  

Microsoft Academic Search

\\u000a San Juan province, located in western Argentina, presents great climate variability with arid characteristics. Mean annual\\u000a rainfall averages less than 100 mm for the whole province, and snowmelt in the Andean upper basin provides the San Juan River\\u000a Basin with seasonal streamflow during summer, the period of highest water demand for irrigation.\\u000a Traditional streamflow forecasts for the San Juan River are

Juan Carlos Gimenez; Emilio Juan Lentini; Alicia Fernández Cirelli

322

Geomorphological and sedimentological features in Quaternary fluvial systems affected by solution-induced subsidence (Ebro Basin, NE-Spain)  

NASA Astrophysics Data System (ADS)

The Quaternary evolution and the morpho-sedimentary features of some of the most important rivers in Spain (Ebro and Tagus rivers among others) have been controlled by subsidence due to alluvial karstification of the evaporitic bedrock. The subsidence mechanism may range from catastrophic collapse to slow sagging of the alluvium by passive bending. In the Ebro Basin, the mechanisms and processes involved in karstic subsidence were studied through the analysis of present-day closed depressions as well as through old subsidence depressions (palaeocollapses and solution-induced basins) and associated deformations recorded in the Quaternary alluvial sediments. The Gállego-Ebro river system is presented as a case study of channel adjustments and geomorphic and sedimentary evolution of fluvial systems in dissolution-induced subsidence areas. In this fluvial system, evaporite dissolution during particular Quaternary time intervals (namely early and middle Pleistocene) have lead to the development of a solution-induced basin, approximately 30 km-long by 8 km-wide, filled by Quaternary deposits with a total thickness in excess of 190 m. The main river response to balance the subsidence in the alluvial plain was aggradation in the central reach of the subsiding area, and degradation both in the upstream reach and in the valley sides where alluvial fans and covered pediments may prograde over the fluvial sediments. The main sinking areas are recognized in the sedimentary record by anomalous thickenings in the alluvial deposits and fine-grained sediments deposited in backswamp and ponded areas.

Benito, Gerardo; Gutiérrez, Francisco; Pérez-González, Alfredo; Machado, Maria J.

2000-06-01

323

Forum for Integrated Resource Management (FIRM) in Ephemeral Basins: Putting communities at the centre of the basin management process  

NASA Astrophysics Data System (ADS)

Increasingly there is need for efforts integrating natural resource management inclusive of water, land, and biodiversity with actions and developments of humans, particularly in heavily used, sensitive environments such as arid river basins. Integrated Water Resource Management (IWRM) provides the basis for this integration. One such approach used in Namibia is known as the Forum for Integrated Resource Management (FIRM), which aims to enable communities to take a central role in management and development processes in their areas. This approach has recently been tested in the Kuiseb Ephemeral River Basin with the active participation of basin stakeholders. The use of FIRM in basin management requires certain adaptations, especially in the context of ephemeral river basins. The main focus of discussion is how FIRM may be applied to basin management in ephemeral basins, highlighting a case study of the basin management process in the Kuiseb Basin in Namibia. An analysis of similarities and differences between FIRM and its application in basin management is also undertaken, illustrating how the concept is applied to basin management in ephemeral basins, particular lessons learnt and strengths of this approach. The paper concludes with recommendations on how FIRM may be established in basin management with the Kuiseb River basin providing empirical evidence of the positive potential of such an approach.

Manning, Nadia; Seely, Mary

324

A semi-distributed, physics-based hydrologic model using remotely sensed and Digital Terrain Elevation Data for semi-arid catchments  

Microsoft Academic Search

A practical, hydrologic model (DPHM-RS) is developed for the semi-arid climate of the Canadian Prairies that could adequately account for a river basin's terrain features by sub-dividing it to sub-basins of uneven shapes and sizes (semi-distributed) based on topographic information derived from the digital terrain elevation (DTED) data. Even though computationally modest, DPHM-RS is scientifically vigorous, can effectively assimilate remotely

Getu Fana Biftu

2004-01-01

325

Gravel-Sand Transition in a Large, Lowland Alluvial Channel.  

NASA Astrophysics Data System (ADS)

The beds of alluvial river channels become finer grained moving downstream and often exhibit an abrupt transition from gravel to sand-bedded conditions. Most previous work documenting this phenomenon have focused on small upland streams where sediment supply to the channel is strongly connected to sediment delivery from hillslopes. Fewer studies have focused on the gravel-sand transition in large alluvial channels and none have documented the spatial variability through reaches where transitions occur. The downstream fining pattern observed in the Fraser River is widely cited as a classic example of an abrupt gravel-sand transition in a large alluvial channel. However, important questions regarding the exact current location of the transition, its morphology, and what controls its location remain unanswered. Here, we present detailed observations of bed material grain-size and river bed topography through the reach where the transition is widely thought to occur in the Fraser River. Bed topography was measured using a multibeam echo- sounding system (Reson 8101 Seabat) at high flow (11,000 m3s-1) when all fractions of the bed material were mobile. Some limited bed material sampling was done at high flow with more detailed sampling at low flows (~1000 m3s-1). These observations indicate that there is little gravel material on the active channel bed downstream of Yaalstrick Bar, the last bar along the river dominated by gravel (> 75% of the bar material > 2 mm). However, sorting patterns caused by the superior mobility of gravel over sand have lead to gravel patches on the upstream sides and surfaces of sand bars. There are also gravel patches along the thalweg through the apex of some river bends, but whether this is topographically induced sorting or a lag deposit exposed by high flow is not clear. Bedforms associated with sand-gravel mixtures appear on the river bed immediately downstream of Yaalstrick Bar in a sequence (sand ribbons, barchans, dunes) suggesting sand deposition from suspension. There is also a dramatic increase in bar amplitude downstream of Yaalstrick Bar, suggesting greater sand composition. Our observations suggest the gravel- sand transition in the Fraser River is somewhat more diffuse than is observed in smaller scale channels. Yet, for all practical purposes, Yaalstrick Bar is the end of the gravel-bedded reach of the Fraser River.

Venditti, J. G.; Humphies, R. P.; Allison, M. A.; Nittrouer, J. A.; Church, M.

2008-12-01

326

Evaluating the impacts of drought stress on arid and semi-arid ecosystems in Northeast Asia using satellite imagery data  

NASA Astrophysics Data System (ADS)

Drought stress on vegetation growth can lead alteration in function and structure of ecosystem. Severe drought in arid and semi-arid area may result in reduction of vegetation productivity or biomass as well as alteration of species composition of ecosystem. Previous studies have commonly used precipitation data to assess the effect of water stress on dryland ecosystems. However, soil moisture would be better water-related environmental variable than precipitation because it affects stomata behavior. The remote sensing data derived from satellite imagery are useful to monitor ecological processes such as vegetation production and its response to soil moisture in broad regions. For instance, the GIMMS AVHRR Normalized Difference Vegetation Index (NDVI) data as well as soil moisture data detected by Special Sensor Microwave Imager (SSM/I) soil moisture data have potentials to examine the associations between water stress and vegetation productivity across entire Northeast Asia. The productivity index (i.e. accumulated, maximum, mean NDVI) derived from NDVI may have considerable uncertainty to represent vegetation productivity. Hence, we tested whether the productivity index can be surrogate of vegetation productivity from MODIS cloud-corrected annual GPP. As well, soil moisture from SSM/I lacks credibility in areas where vegetation is dense. We confined our study areas where significant correlation between precipitation record and SSM/I soil moisture occurred. The purposes of this study are (1) to examine the spatial and temporal patterns of soil moisture and productivity indices in arid and semi-arid regions of Northeast Asia from 1987 to 2006, and (2) to investigate how the drylands productivity responded to inter-annual soil moisture variability, and (3) to examine how the drylands productivity was sensitive to the change of soil moisture. Finally, (4) it was evaluated the spatial and inter-annual patterns of drought stress in the Northeast Asia drylands (i.e. soil moisture-based water use efficiency). For those purposes, correlation and sensitivity (i.e. slope of linear regression between productivity index and soil moisture) were examined and utilized to evaluate the spatial and temporal patterns of the relations. The analyses indicated that (1) strong positive correlations existed between soil moisture and productivity indices in the most of arid and semi-arid ecosystems, even though negative correlations were also observed at a regional scale such as in Tarim Basin; (2) in particular, grassland ecosystems in Mongolia near the Gobi desert showed the most conspicuous sensitivity to drought stresses; (3) the regions and periods of severe drought stress showed higher water use efficiency. In this presentation, the results from our combined analysis between the productivity index and soil moisture were utilized to discuss resistance and vulnerability of dryland ecosystems to drought stress. Acknowledgement: This work was funded by the Korea Meteorological Administration Research and Development Program under Grant RACS 2010-4014.

Do, N.; Kang, S.; Choi, G.

2010-12-01

327

Late Holocene Soil Stratigraphy and Geochronology of Alluvial Sedimentation in the Sonoran Desert, Arizona  

NASA Astrophysics Data System (ADS)

The integration of soil stratigraphic investigations and radiocarbon dating at two sites in combination with geomorphic mapping at scales of 1:50k and 1:5k offer insight to the timing and magnitude of alluvial sedimentation during the late Holocene within the Sonoran Desert near Yuma, Arizona. Mapping at 1:50k was performed over an area of 3400 km2 and alluvial landforms were labeled Qf1 to Qf5, from oldest to youngest, using 1- and 5-meter resolution satellite imagery within the U.S. Army Yuma Proving Ground (YPG). Approximately 70% of the identified landforms within YPG are Quaternary alluvial fans, alluvial plains, and active washes, whereas the other 30% consist of mountain highlands, pediments, and badlands. In the southwest portion of YPG near Muggins Mountains, alluvial fan terraces (Qf4) positioned 0.5 m above active washes are characterized as having moderate bar-and-swale microtopography, moderately developed desert pavement, and a Av/ Bw/ Cky/ Cky1/ Cky2/ Cky3 gravelly soil profile. A large piece of charcoalized Ironwood ( Olneya tesota) was recovered from a depth of 0.75 m and yielded three AMS 14C dates that range from 3330 to 2860 cal yr B.P. Geomorphic mapping at a scale of 1:5k indicates that in an area of 25 km2 at the site, the distribution of late Holocene alluvial fan terraces comprise 17% of the surrounding Quaternary alluvium. Similar aged alluvial features were observed about 70 km to the north near South Trigo Peak at YPG. Terraces of a broad and flat alluvial plain positioned 0.5 m above active channels are characterized as having moderate bar- and-swale microtopography, poorly developed desert pavement, and a AC/ C/ Bwkb1/ Bwk1b2/ Bwk2b2/ BCkb2/ Bwkb3 sandy soil profile. A terrestrial gastropod shell ( Lymnea sp.) fragment was recovered from a depth of 0.5 m and yielded an AMS 14C date of 2360-2310 cal yr B.P. Additional geomorphic mapping at 1:5k shows that in an area of 30 km2, the distribution of late Holocene alluvial plain terraces and equivalent alluvial fans include 35% of the surrounding Quaternary alluvium. Of the total Quaternary alluvium identified at 1:50k, 10% of the landforms consist of gravelly alluvial fans and sandy alluvial plains deposited between 3330 and 2310 cal yr B.P. The numerical ages and associated soil development provide evidence of regional alluvial sedimentation near Yuma, Arizona, and provides well constrained geomorphic data for paleoclimatic modeling in the Sonoran Desert during the late Holocene.

Bacon, S. N.; McDonald, E. V.; Dalldorf, G. K.; Caldwell, T. G.

2007-12-01

328

Petrology, geochemistry, and Na metasomatism of Triassic-Jurassic non-marine clastic sediments in the Newark, Hartford, and Deerfield rift basins, northeastern USA  

Microsoft Academic Search

Many sandstones and associated siltstones and shales of the Triassic-Jurassic Newark Supergroup in the Newark, Hartford, and Deerfield rift basins are immature feldspathic alluvial and lacustrine closed-basin deposits. They were derived from felsic igneous and metamorphic continental blocks on the flanks of their depositional basins. The provenance was dominantly calc-alkaline basement rocks similar to the Sierra Nevada of California. The

Peter C. van de Kamp; Bernard E. Leake

1996-01-01

329

Hierarchy of responses to resource pulses in arid and semi-arid ecosystems  

Microsoft Academic Search

In arid\\/semi-arid ecosystems, biological resources, such as water, soil nutrients, and plant biomass, typically go through periods of high and low abundance. Short periods of high resource abundance are usually triggered by rainfall events, which, despite of the overall scarcity of rain, can saturate the resource demand of some biological processes for a time. This review develops the idea that

Susanne Schwinning; Osvaldo E. Sala

2004-01-01

330

Renewable and non-renewable groundwater in semi-arid and arid regions  

Microsoft Academic Search

For thousands of years humans have adapted to live within the limits of the water cycle. Groundwater has generally provided reliability in supplied in semi-arid and arid regions through periods of drought, but now, within a generation, a global water crisis has developed,due to poor resource management since the scientific evidence has been clear, that water withdrawals exceed natural rates

W. Mike Edmunds

2003-01-01

331

Structural and Animal Species Diversity in Arid and Semi-arid Savannas of the Southern Kalahari  

Microsoft Academic Search

The world is witnessing a decline in species diversity. In order to explore and preserve species diversity, ecologists still search for fundamental principles which may shape species diversity patterns in space and time. In arid and semi-arid savannas of the southern Kalahari in Southern Africa land use and climate change are two anthropogenic drivers which have a considerable impact on

Jörg Tews; Niels Blaum; Florian Jeltsch

2004-01-01

332

Nonlinear dynamics in arid and semi-arid systems: Interactions among drivers and processes across scales  

Microsoft Academic Search

We discuss a new conceptual framework for arid and semi-arid systems that accounts for nonlinear dynamics and cross scale interactions in explaining landscape patterns and dynamics. Our framework includes a spatial and temporal hierarchy, and five key interacting components that connect scales of the hierarchy and generate threshold behaviors: (1) historical legacies that include climate, disturbance, and management regimes, (2)

D. P. C. Peters; K. M. Havstad

2006-01-01

333

Resource pulses, species interactions, and diversity maintenance in arid and semi-arid environments  

Microsoft Academic Search

Arid environments are characterized by limited and variable rainfall that supplies resources in pulses. Resource pulsing is a special form of environmental variation, and the general theory of coexistence in variable environments suggests specific mechanisms by which rainfall variability might contribute to the maintenance of high species diversity in arid ecosystems. In this review, we discuss physiological, morphological, and life-history

Peter Chesson; Renate L. E. Gebauer; Susan Schwinning; Nancy Huntly; Kerstin Wiegand; Morgan S. K. Ernest; Anna Sher; Ariel Novoplansky; Jake F. Weltzin

2004-01-01

334

Precipitation Management for Reclamation of Overgrazed Areas in Arid and Semi-Arid Regions.  

National Technical Information Service (NTIS)

An investigation was made of the feasibility of using precipitation management as a method for the vegetative restoration of strip mine spoils in arid and semi-arid areas, and for the economic and environmental improvement of reclaimed mine spoils. The pr...

N. S. Grigg

1976-01-01

335

Quality issues in harvested rainwater in arid and semi-arid Loess Plateau of northern China  

Microsoft Academic Search

Loess soils cover vast areas in the arid and semi-arid regions of northern China. Due to the lack of reliable surface water and ground-water, rainwater harvesting has played a prominent role in farmers’ domestic usage and agricultural irrigation. An economical and valid type of water storage cistern with optimum design of components has been introduced to rural areas in the

Kun Zhu; Linus Zhang; William Hart; Mancang Liu; Hui Chen

2004-01-01

336

Water harvesting techniques for small communities in arid areas.  

PubMed

Limited water resources exist in numerous remote indigenous settlements around Australia. Indigenous people in these communities are still living in rudimentary conditions while their urban counterparts have full amenities, large scale water supplies and behavioral practices which may not be appropriate for an arid continent but are supported by extensive infrastructure in higher rainfall coastal areas. As remote indigenous communities continue to develop, their water use will increase, and in some cases, costly solutions may have to be implemented to augment supplies. Water harvesting techniques have been applied in settlements on a small scale for domestic and municipal purposes, and in the large, broadacre farm setting for productive use of the water. The techniques discussed include swales, infiltration basins, infiltration trenches and "sand dam" basins. This paper reviews the applications of water harvesting relevant to small communities for land rehabilitation, landscaping and flood control. Landscaping is important in these communities as it provides shelter from the sun and wind, reduces soil erosion and hence reduced airborne dust, and in some cases provides food and nutrition. Case studies of water harvesting systems applied in the Pilbara Region, Western Australia for landscaping around single dwellings in Jigalong and Cheeditha, in a permaculture garden in Wittenoon and at a college and carpark in Karratha are described. PMID:11700659

Yuen, E; Anda, M; Mathew, K; Ho, G

2001-01-01

337

Estimating contaminant attenuation half-lives in alluvial groundwater systems  

SciTech Connect

One aspect of describing contamination in an alluvial aquifer is estimating changes in concentrations over time. A variety of statistical methods are available for assessing trends in contaminant concentrations. We present a method that extends trend analysis to include estimating the coefficients for the exponential decay equation and calculating contaminant attenuation half-lives. The conceptual model for this approach assumes that the rate of decline is proportional to the contaminant concentration in an aquifer. Consequently, the amount of time to remove a unit quantity of the contaminant inventory from an aquifer lengthens as the concentration decreases. Support for this conceptual model is demonstrated empirically with log-transformed time series of contaminant data. Equations are provided for calculating system attenuation half-lives for non-radioactive contaminants.

Tardiff, Mark F.; Katzman, Danny

2007-03-13

338

Interpretation of alluvial beds through bed-elevation distribution moments  

NASA Astrophysics Data System (ADS)

With equipment advances now enabling the measurement and processing of alluvial-bed elevation data at high spatial and temporal resolutions, the moments of measured bed-elevation distributions can be used to characterize riverbed structure. From analyses of a wide range of high-quality data sets for a range of flows, sediments, and types of bed surface (e.g., armoured gravels, uniform sands, ripples, and dunes), at laboratory and field scales, the standard deviation of bed elevations ? is found to provide a robust integral measure of bed-roughness height. This approach has the statistical advantage of utilizing all relevant bed-elevation information, and also removes any potential need to subjectively identify valid individual roughness elements within the measured bed data. In addition to ? defining the vertical roughness scale for a bed surface, the general shape of the bed surface forms or elements can be characterized by the bed-elevation distribution skewness Sk, with the distribution kurtosis Ku providing a measure of the evenness or intermittency of these elements. Based on the present analyses, a schematic Sk-Ku plane is presented to aid interpretation of the structure of steady state and developing alluvial bed surfaces from measured bed-elevation distributions, where various bed surface types (e.g., artificially smoothed beds, armoured gravel beds, planar beds of mobile uniform sediments, ripples, and dunes) can be differentiated based on this diagram. Relatively large values of Ku that can occur for a measured riverbed surface are associated with intermittent bed-roughness elements, as can arise for supply-limited dunes or widely distributed pebble clusters or bed forms on an otherwise plane bed.

Coleman, Stephen E.; Nikora, Vladimir I.; Aberle, Jochen

2011-11-01

339

The Nubian Sandstone Basin in North Africa, A Source of Irrigation Water for Desert Oases  

Microsoft Academic Search

\\u000a The Nubian sandstone basin in northern Africa is presented in this paper. This basin has total a total surface of about 1.8\\u000a million km2encompassing the north-western part of the Sudan, Egypt west of the Nile, the extreme north-east of Chad and southern and\\u000a eastern Libya. This surface is characterized by its extreme aridity. Groundwater is present in the Nubian basin

Mamdouh Shahin

340

Freshwater mussel assemblage structure in a regulated river in the Lower Mississippi River Alluvial Basin, USAy  

Microsoft Academic Search

This paper documents a diverse, reproducing freshwater mussel community (20 species) in Lower Lake } an impounded, regulated portion of the Little Tallahatchie River below Sardis Dam in Panola Co., Mississippi, USA. 2. Despite being regulated and impounded, the lake has a heterogeneous array of habitats that differ markedly in mussel community attributes. Four distinct habitat types were identified based

WENDELL R. HAAG; MELVIN L. WARREN

341

Geological studies of Adriatic alluvial plans as a key aspect for water basins Investigations  

Microsoft Academic Search

If we want to know the exact water supply available for the national economy, we have to study the position and the geometry of aquifers, as well as the amount and quality of water stirred therein. It required the implementation of observation wells Human cultures evolved on plains. Agricultural production was the most important activity in the millennia preceding the

Jakup Hoxhaj; Rakip Hysenaj; Vera Gjoni; Hasan Kuliçi

342

Assessment of thermal stratification within stream pools as a mechanism to provide refugia for native trout in hot, arid rangelands  

Microsoft Academic Search

Native trout species, such as the redband trout (Oncorhynchus mykiss), occupy thermally harsh stream habitats in hot, arid rangeland basins of the western United States. Declines in the distribution\\u000a and abundance of these species has generated interest in understanding how these cold water species survive in these systems,\\u000a as well as in identifying opportunities to restore these species to their

kenneth W. tate; donald L. lancaster; david. F. lile

2007-01-01

343

Identifying recharge pattern using stable isotopes of rainfall in semi arid subtropical northwest Australia  

NASA Astrophysics Data System (ADS)

The water resources in the semi-arid subtropical Hamersley Basin, is currently subject to increasing pressure from altered hydrology associated with mining activities as well as water abstraction for regional development. Sustainable water management across the Basin therefore must be underpinned by an understanding of the factors that constrain water supply in arid zones. This study used stable isotopic composition of rainwater, groundwater, and surface water to demonstrate the importance of evaporation of rain droplets during rainfall events. We clearly show the importance of the so-called "rain out" effect at the regional scale. We also developed a local meteoric line to determine the recharge dynamics to the aquifers in the Hamersley Basin. We found that ?2H and ?18O values for rainfall events >20 mm were consistent with fresh groundwater, suggesting that groundwater recharge primarily occurs during intense and high volume rainfall events. The chemical composition and ?2H and ?18O values of rain, surface and groundwater were also used to develop a model for the chemical evolution of water from rainfall to fresh groundwater and ultimately highly saline groundwater.

Dogramaci, S.; Skrzypek, G.; Dodson, W.; Grierson, P.

2012-04-01

344

Ecological effects of water retention in the River Rhine valley: a review assisting future retention basin classification  

Microsoft Academic Search

This review paper summarizes the ecological effects of the use of floodplains and flood retention basins to control river flow in the River Rhine (Rhein) valley. Early River Rhine regulation strategies including channel straightening are assessed. The subsequent disappearance of alluvial hardwood forests has been highlighted as the major disadvantage. The response of trees to more recent strategies such as

M. Scholz

2007-01-01

345

The influence of fires on the properties of forest soils in the Amur River basin (the Norskii Reserve)  

Microsoft Academic Search

The influence of forest fires on the properties of taiga brown, gley taiga brown, and alluvial bog soils widespread in the area of the Norskii Reserve (the Amur River basin) was studied. During several years after the fire, the humus content increased, especially in the soils subjected to fires of high intensity. In the soils of steep slopes, the humus

A. S. Tsibart; A. N. Gennadiev

2008-01-01

346

The formation of beds underlying carbonaceous shales as aquic paleosols: examples from the Bighorn Basin of Wyoming  

Microsoft Academic Search

Drab, grey mudrocks consistently occur below carbonaceous shales in lower Tertiary alluvial sediments of the Western Interior basins of the USA. Superficially these mudrocks, here termed underbeds, look similar to underclays commonly found below coal beds. However, it is unclear whether the association between the carbonaceous shales and the underbeds is genetic, or whether underbed features developed independently, before the

K. Sian Davies-Vollum

1999-01-01

347

Naktodemasis bowni: New Ichnogenus and Ichnospecies for Adhesive Meniscate Burrows (AMB), and Paleoenvironmental Implications, Paleogene Willwood Formation, Bighorn Basin, Wyoming  

Microsoft Academic Search

Adhesive meniscate burrows (AMB) are common in alluvial paleosols of the Paleogene Willwood Formation, Bighorn Basin, Wyoming. AMB are sinuous, variably oriented burrows composed of a nested series of distinct, ellipsoidal packets containing thin, tightly spaced menisci subparallel to the bounding packet. Menisci are non-pelleted and texturally homogeneous with each other and the surrounding matrix. AMB were constructed most likely

Jon J. Smith; Stephen T. Hasiotis; Mary J. Kraus; Daniel T. Woody

2008-01-01

348

Geomorphological and sedimentological features in Quaternary fluvial systems affected by solution-induced subsidence (Ebro Basin, NE-Spain)  

Microsoft Academic Search

The Quaternary evolution and the morpho-sedimentary features of some of the most important rivers in Spain (Ebro and Tagus rivers among others) have been controlled by subsidence due to alluvial karstification of the evaporitic bedrock. The subsidence mechanism may range from catastrophic collapse to slow sagging of the alluvium by passive bending. In the Ebro Basin, the mechanisms and processes

Gerardo Benito; Francisco Gutiérrez; Alfredo Pérez-González; Maria J Machado

2000-01-01

349

Basin and range-age reactivation of the ancestral Rocky Mountains in Texas Panhandle: evidence from Ogallala Formation  

Microsoft Academic Search

The Ogallala Formation (Neogene) is a widespread syntectonic alluvial apron that was shed eastward from the Rio Grande rift and related uplifts in Colorado and New Mexico during Basin and Range extension. In the Texas Panhandle, the Ogallala completely buried Ancestral Rocky Mountain (Pennsylvanian) structures. Renewed movement on these older structures during the Neogene influenced the thickness and facies distribution

Roy T. Budnik

1984-01-01

350

Characteristics of chemistry and stable isotopes in groundwater of Chaobai and Yongding River basin, North China Plain  

Microsoft Academic Search

To identify the groundwater flow system in the North China Plain, the chemical and stable isotopes of the groundwater and surface water were analysed along the Chaobai River and Yongding River basin. According to the field survey, the study area in the North China Plain was classified hydrogeologically into three parts: mountain, piedmont alluvial fan and lowland areas. The change

K. Aji; C. Tang; X. Song; A. Kondoh; Y. Sakura; J. Yu; S. Kaneko

2008-01-01

351

Human Exposure to Mercury and the Accumulation of Methylmercury that is Associated with Gold Mining in the Amazon Basin, Brazil  

Microsoft Academic Search

In order to evaluate the extent of human exposure to mercury in the Amazon, in particular, in the Tapajos River basin, which is a site of extensive alluvial gold mining, we analyzed samples of human hair, blood and urine, as well as fish, collected from different areas for total levels of mercury and methylmercury. In fishing villages, the inhab- itants

Hirokatsu Akagi; Akira Naganumab

352

Facies architecture and paleohydrology of a synrift succession in the Early Cretaceous Choyr Basin, southeastern Mongolia  

USGS Publications Warehouse

The Choyr Basin is one of several Early Cretaceous rift basins in southwestern Mongolia that developed in specific regions between north-south trending fold-and-thrust belts. The eastern margin of the basin is defined by high-angle normal and/or strike-slip faults that trend north-to-south and northeast-to-southwest and by the overall geometry of the basin, which is interpreted to be a half graben. The sedimentary succession of the Choyr Basin documents one of the various types of tectono-sedimentary processes that were active in the rift basins of East Asia during Early Cretaceous time. The sedimentary infill of the Choyr Basin is newly defined as the Khalzan Uul and Khuren Dukh formations based on detailed mapping of lateral and vertical variations in component lithofacies assemblages. These two formations are heterotopic deposits and constitute a third-order fluvio-lacustrine sequence that can be divided into transgressive and highstand systems tracts. The lower part of the transgressive systems tract (TST) is characterized by sandy alluvial-fan and braided-river systems on the hanging wall along the western basin margin, and by a gravelly alluvial-fan system on the footwall along the eastern basin margin. The alluvial-fan and braided-river deposits along the western basin margin are fossiliferous and are interpreted to have developed in association with a perennial fluvial system. In contrast, alluvial-fan deposits along the eastern basin margin do not contain any distinct faunas or floras and are interpreted to have been influenced by a high-discharge ephemeral fluvial system associated with fluctuations in wetting and drying paleohydrologic processes. The lower part of the TST deposit fines upward to siltstone-dominated flood-plain and ephemeral-lake deposits that constitute the upper part of the TST and the lower part of the highstand systems tract (HST). These mudstone deposits eventually reduced the topographic irregularities typical of the early stage of synrift basin development, with an associated decrease in topographic-slope gradients. Finally, a high-sinuosity meandering river system drained to the south during the late highstand stage in response to the northward migration of the depocenter. The upper HST deposits are also fossiliferous and are interpreted to have been influenced by a perennial fluvial system, although the average annual discharge of this system was probably less than 5 percent of that involved in the formation of the lower TST deposits along the western basin margin. ?? 2006 Elsevier Ltd. All rights reserved.

Ito, M.; Matsukawa, M.; Saito, T.; Nichols, D. J.

2006-01-01

353

Arid site characterization and technology assessment: Volatile Organic Compounds-Arid Integrated Demonstration  

SciTech Connect

The US Department of Energy`s (DOE`s) Volatile Organic Compounds-Arid Integrated Demonstration (VOC-Arid ID) program was initiated in March 1991 to evaluate technologies for all phases of remediation of VOCs in soils and groundwater at DOE arid/semiarid sites. The primary site for field demonstrations under the VOC-Arid ID program is the Hanford Site. The purpose of this report is to describe (1) the bases for technologies currently under evaluation in the VOC-Arid ID program; (2) the types of subsurface contamination at DOE arid/semiarid sites; and (3) the areas of potential common technology interests based on perceived technology needs at other DOE sites. This report was compiled by Pacific Northwest Laboratory in response to DOE`s Office of Technology Development`s mission to carry out an aggressive program to accelerate the development and implementation of new and existing technologies to meet a 30-year goal set by DOE in June 1989 to clean up all of its sites and to bring all sites into compliance with current and future environmental regulations. A key component of this program is the development of technologies that are better, faster, safer, and cheaper than those technologies currently available. Included in this report are an evaluation of technologies currently (fiscal year 1993) being pursued at the Hanford Site under the auspices of the VOC-Arid ID program, an assessment of subsurface contaminants at arid/semiarid sites, a summarization of technologies under consideration at other DOE sites, a discussion of areas of potential common technology interests, and the conclusions. Also included are a summary of the extent of contamination at the DOE arid/semiarid sites under consideration and a bibliography of source documents from which this report was prepared.

Riley, R.G.

1993-06-01

354

Modified High-resolution Sequence Stratigraphy of Alluvial Sediments Based on Modern Geomorphology  

Microsoft Academic Search

The short-term base level cycle was subdivided into two types in the established high-resolution sequence stratigraphic model of alluvial deposits, namely deepening-upward unsymmetrical type and symmetrical type, which all stress that the common \\

Lan Chaoli; Zhang Junfeng; Tao Weixiang

2010-01-01

355

30 CFR 947.822 - Special performance standards-operations on alluvial valley floors.  

Code of Federal Regulations, 2013 CFR

...THE CONDUCT OF SURFACE MINING OPERATIONS WITHIN EACH STATE WASHINGTON § 947.822 Special performance standardsâoperations...alluvial valley floors, except in those coalfields in Washington west of the crest of the Cascade Mountain...

2013-07-01

356

A Numerical Model of Retreating Alluvial Fan Coasts  

NASA Astrophysics Data System (ADS)

A numerical model has been developed that simulates the wave-driven retreat of partially-consolidated alluvial- fan shores over millennium time-scales. It has been developed to reproduce the shore profiles and coastal erosion rates observed along the Pleistocene glacial-outwash fan built by the Waitaki River on the east coast of New Zealand's South Island. This cliffed shore is currently fronted by a narrow sand-and-gravel beach. The nearshore seabed is formed in Pleistocene substrate and has only a thin and patchy cover of sand. The motivation is to examine the sensitivity of the erosion rates to wave-climate change, sea-level rise, and river sediment supplies. The model is forced by two wave conditions that, when randomly sampled, represent the storm-wave and normal-swell climates of the prototype coast. These each operate for a fixed proportion of the model's yearly time-step. Morphological change is driven by a series of coupled process models. These include scour of the nearshore seabed by shoaling waves, cross-shore exchanges of sand and gravel between the nearshore and beach, berm construction during normal wave conditions, berm overtopping by storm waves with consequent beach stripping and scour of the exposed sub-aerial substrate and cliff-toe notch-cutting, gravity-failure of the cliffs and talus construction between storm events, and beach sediment abrasion. The scour, notching, and transport models are generally based on energetics principles and are calibrated with linear scaling coefficients to match field observations from the prototype coast. Negative feedback regulates the rate of cliff erosion through the protection that is afforded by cliff and substrate material added to the beach. The starting model condition is a sloping alluvial fan inundated by the sea-level rise that followed the last glacial epoch, and the model is run for 6000 years to the present assuming a stable sea level. Initially, the gentle slope of the alluvial fan results in quite rapid rates of seafloor lowering under the shoaling and breaking waves, which in turn results in the rapid development of a large gravel barrier fed by the material excavated from the nearshore. As the nearshore profile approaches equilibrium, this onshore supply lessens and abrasion begins to reduce the beach volume. As a result, the beach size reduces to a threshold at which storm waves periodically overtop and strip part or all of the beach. The associated scour of the substrate beneath the sub- aerial beach initiates a proto-cliff. The modeled shore then settles into a mode of ongoing retreat with gradually increasing cliff height and a landward-translating nearshore profile. From this stage, the beach volume settles to an equilibrium value, while the cliff retreat rate declines in inverse proportion to the cliff height. The equilibrium volume and retreat rates are a function of the wave climate and the substrate material properties. The model was verified from the nearshore and shore-cliff profiles of the prototype coast, assuming that these have evolved over the past ~ 6000 year sea-level still-stand. The current model formulation is 1-d, assuming zero divergence in the longshore transport field. Work-in- progress is expanding the model to 2-d, to include wave refraction, longshore transport divergence, river sediment inputs, and longshore variability in substrate topography and material properties.

Hicks, M.; Dickson, M.; Coco, G.

2006-12-01

357

The plight of arid land agriculture  

SciTech Connect

This book analyses the problems of the agricultural environment worldwide and possible solutions. Problems covered include the following: famines caused by agricultural land mismanegment in Subsaharan Africa and population increase; improved productivity leading to salinity, erosion, and water depletion; toxic wastes; loging, deforestation, and over-grazing. Agricultural practices, both ancient and modern, in arid lands are described. Food crops suited for arid lands, potential industrial crops, oil extraction from seed and rubber extraction, and biomass as a source of energy are discussed in different chapters. Finally the book deals with optimization of water use, prevention of salinization, and the prospect of global warming.

Hinman, C. W.; Hinman, K.W.

1992-01-01

358

Alluvial aquifers in the Mzingwane catchment: Their distribution, properties, current usage and potential expansion  

NASA Astrophysics Data System (ADS)

The Mzingwane River is a sand filled channel, with extensive alluvial aquifers distributed along its banks and bed in the lower catchment. LandSat TM imagery was used to identify alluvial deposits for potential groundwater resources for irrigation development. On the false colour composite band 3, band 4 and band 5 (FCC 345) the alluvial deposits stand out as white and dense actively growing vegetation stands out as green making it possible to mark out the lateral extent of the saturated alluvial plain deposits using the riverine fringe and vegetation . The alluvial aquifers form ribbon shaped aquifers extending along the channel and reaching over 20 km in length in some localities and are enhanced at lithological boundaries. These alluvial aquifers extend laterally outside the active channel, and individual alluvial aquifers have been measured with area ranging from 45 ha to 723 ha in the channels and 75 ha to 2196 ha on the plains. The alluvial aquifers are more pronounced in the Lower Mzingwane, where the slopes are gentler and allow for more sediment accumulation. Estimated water resources potential ranges between 175,000 m3 and 5,430,000 m3 in the channels and between 80,000 m3 and 6,920,000 m3 in the plains. Such a water resource potential can support irrigation ranging from 18 ha to 543 ha for channels alluvial aquifers and 8 ha to 692 ha for plain alluvial aquifers. Currently, some of these aquifers are being used to provide water for domestic use, livestock watering and dip tanks, commercial irrigation and market gardening. The water quality of the aquifers in general is fairly good due to regular recharge and flushing out of the aquifers by annual river flows and floodwater. Water salinity was found to increase significantly in the end of the dry season, and this effect was more pronounced in water abstracted from wells on the alluvial plains. During drought years, recharge is expected to be less and if the drought is extended water levels in the aquifers may drop substantially, increasing salinity problems.

Moyce, William; Mangeya, Pride; Owen, Richard; Love, David

359

Lithofacies and depositional environments of Miocene deposits from tectonically-controlled basins (Red River Fault Zone, northern Vietnam)  

Microsoft Academic Search

The Lao Cai, Yen Bai and Bao Yen Basins connected with the Red River Fault Zone (RRFZ) are filled with over 1000m thick Neogene (Miocene) clastic deposits of different type and origin. Coarse-grained alluvial deposits predominate along the south-western margin of the Lao Cai and Yen Bai Basins, while different types of conglomerates and sandstones, even siltstones occur in their

Anna Wysocka; Anna ?wierczewska

2010-01-01

360

Sedimentology, stratigraphy and tectonics of evolving wedge-top depozone: Ariano Basin, southern Apennines, Italy  

NASA Astrophysics Data System (ADS)

The late Zanclean wedge-top Ariano Basin, located in the external sector of the southern Apennines, was initially characterized by alluvial and fan-delta environments and successively, southward of the Benevento-Buonalbergo fault, by a gradual drowning with coastal and alluvial plains evolving to shelf and marine coastal settings, respectively. Basin evolution continued with a synsedimentary uplift of different sectors resulting in variations in the drainage pattern and basin shape, and ultimately leading to complete basin closure and transition to continental depositional environments.Early Pliocene paleogeography, prior to the Ariano Basin activity, is due to regional subsidence and subsequent differential uplifts that resulted from geodynamic processes related to both the downgoing Apulian slab and the allochthonous orogenic wedge. Slab break off and the migration of a tear in the southeastward Apulian slab occurred, producing a strong subsidence in the external sectors of the southern Apennines recorded by the development of the Ariano Basin. Subsequently out-of-sequence synsedimentary thrusting, related to thin-skinned tectonics, occurred in the allochthonous units and unconformably overlying wedge-top basin deposits, producing northeastward migration of the main depocenters in the Ariano Basin. Finally renewed thrusting, related to the inversion of pre-existing normal faults located in the buried Apulian Platform and enhanced by regional uplift, affected the whole tectonic and sedimentary pile, as recorded by deformation of the overlying Pliocene deposits.

Ciarcia, Sabatino; Vitale, Stefano

2013-05-01

361

Magnetic properties of alluvial soils polluted with heavy metals  

NASA Astrophysics Data System (ADS)

Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (P?íbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on magnetic extracts indicated the presence of magnetite/maghemite in the uppermost layers, and strong mineralogical transformation of iron oxyhydroxides during heating. Magnetic techniques give valuable information about the soil Fe oxides, which are useful for investigation of the environmental effects in soil. Key words: magnetic methods, Fe oxides, pollution, alluvial soils.

Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

2012-04-01

362

Numerical Simulation of Sediment Plug Formation in Alluvial Channels  

NASA Astrophysics Data System (ADS)

A sediment plug is the aggregation of sediment in a river reach that completely blocks the original channel resulting in plug growth upstream by accretion and flooding in surrounding areas. Sediment plugs historically form over relatively short periods, in many cases a matter of weeks. Although sediment plugs are much more common in reach constrictions associated with large woody debris, the mouths of tributaries, and along coastal regions, this investigation focuses on sediment plug formation in an alluvial river. During high flows in the years 1991, 1995, 2005, and 2008, a sediment plug formed in the San Marcial reach of the Middle Rio Grande. The Bureau of Reclamation has had to spend millions of dollars dredging the channel to restore flows to Elephant Butte Reservoir. The hydrodynamic and sediment transport processes, associated with plug formation, occurring in this reach are driven by 1) a flow constriction associated with a rock outcrop, 2) a railroad bridge, and 3) the water level of the downstream reservoir. The three-dimensional hydrodynamic model, Delft3D, was implemented to determine the hydrodynamic and sediment transport parameters and variables required to simulate plug formation in an effort to identify hydro- and morphodynamic thresholds. Several variables were identified by previous studies as metrics for plug formation. These variables were used in our investigation to detect the relative magnitude of each process. Both duration and degree of high flow events were simulated, along with extent of cohesive sediment deposits, reservoir level, and percent of fines in suspended sediment distribution. Results of this analysis illustrate that this model is able to reproduce the sediment plug formation. Model calibration was based on measured water levels and changes in bathymetry using both sediment transport and morphologic change parameters. Changes to hydraulic and sediment parameters are not proportional to morphologic changes and are asymptotic in their response. These results suggest that there are thresholds to predict plug formation and that the contribution of specific variables to plug formation is not uniform. Sediment plug formation is a costly and dangerous phenomenon, especially in large alluvial rivers. This investigation yielded specific insights into the hydrodynamic and morphologic processes occurring during sediment plug formation. These insights can be used to reduce the risk of plug formation and predict the locations and times of other sediment plugs.

Posner, A. J.; Duan, J. G.

2011-12-01

363

Thermophysical Characterization of Terrestrial Alluvial Fans, With Applications to Mars  

NASA Astrophysics Data System (ADS)

Visible and infrared spectral remote sensing are currently being used to map lithologic variation on Mars, but these techniques are only sensitive to a depth equivalent to a few times the wavelength of observation (several 10's of microns at most). Thus, a fine regolith can make it difficult to characterize the geology of a surface based on spectral properties. This problem can be partially ameliorated by using thermal infrared temperature images. The temperature of the surface is controlled by material within approximately one diurnal thermal skin depth (typically a few cm) of the surface. Thermal images "see below" thin, spectrally obscuring surface layers, and enable the mapping of some underlying geologic heterogeneities (but not mineral compositions). Temperature variation is related, in part, to differences in thermal inertia, which in turn are related to lithology, particle size, degree of induration, and (for Earth) moisture content. THEMIS (and other) images of the Martian surface reveal a variety of features that may be the result of sedimentary processes. Earth analogs have been proposed for many of these features, but very little terrestrial analog work has been done to establish whether particular classes of sedimentary features have distinctive spatial-thermophysical signatures. Sedimentary processes often lead to sorting of grain sizes and/or varying degrees of cementation, so it is reasonable to expect that such signatures might exist. Here we present the results of a preliminary study of alluvial fans in Death Valley. As seen from above in ASTER nighttime thermal infrared images, these fans display distinct "thermophysical facies." Each fan apex has a relatively high thermal inertia, mid-fan areas have intermediate thermal inertias, and distal terminus areas have relatively low thermal inertias. This pattern of thermal inertias is consistent with field-based grain size studies that have been conducted on other debris flow-dominated fans in the area. We have also collected ground-based thermal images of one fan over a 24-hour insolation cycle in order to construct a "hypertemporal image cube" in which each spatial pixel contains a complete diurnal temperature curve. Principle component transformation of this unique data product allows us to separate the effects of surface geometry, shadows, and thermal inertia on surface temperatures. Our intent is to collect more such observations of alluvial fans and other sedimentary structures and compare them with nighttime THEMIS images of proposed analog structures on Mars.

Moersch, J. E.; Whisner, S. C.; Hardgrove, C.

2005-12-01

364

Rapid migration of heavy metals and 137 Cs in alluvial sediments, Upper Odra River valley, Poland  

Microsoft Academic Search

The studies presented explore post-depositional changes of zinc, cadmium, lead, manganese and 137Cs distribution in alluvial sediments accumulated in the upper Odra River valley in southern Poland. The rate of these changes\\u000a was estimated by comparing metal and 137Cs distributions in four vertical alluvial profiles with a history of river pollution and sediment deposition. The untypical\\u000a 137Cs distribution with peaks

Dariusz Ciszewski; Agnieszka Czajka; Sylwia B?a?ej

2008-01-01

365

Channel form and processes in bedrock and alluvial reaches of the Raritan River, New Jersey  

Microsoft Academic Search

Fluvial geomorphologists have generally considered alluvial and bedrock channels to be fundamentally different in character, alluvial channels being shaped by sediment-transport processes and bedrock channels being shaped by structural and lithologic controls. This study examines a 12-km bedrock-floored reach of the Raritan River that separates two gravel-bed reaches, above and below. The bedrock channel has a patchy veneer of sandy

Gail M. Ashley; William H. Renwick; Gary H. Haag

1988-01-01

366

The Holocene Alluvial Delta Relief Complex and Hydrological Regime of the Lena River Delta  

Microsoft Academic Search

Summary: This study presents the geological-geomorphologic characreristics of the Holocene alluvial-delta relief complex of the Lena River delta and deposits comprising it. A complex of the Holocene alluvial-delta relief is represented by a set of channel forrns ancl a low floodplain of modern age, a high floodplain fonning from the end of the Early-Late Holocene and the first above- the

Elena Yu; Marina V. Dorozhkina

367

ADSORPTION–DESORPTION, PERSISTENCE, AND LEACHING BEHAVIOR OF DITHIOPYR IN AN ALLUVIAL SOIL OF INDIA  

Microsoft Academic Search

Investigations were undertaken to determine the adsorption–desorption, persistence and leaching of dithiopyr (S,S?-dimethyl 2-difluoromethyl-4-isobutyl-6-trifluoromethyl pyridine-3,5-dicarbothioate) in an alluvial soil under laboratory condition. The adsorption–desorption studies were carried out using batch equilibration technique. The mass balance studies showed that 83–97% of the pesticide was recovered during adsorption–desorption studies. The results revealed strong adsorption of dithiopyr in alluvial soil with Kd values

Suman Gupta; V. T. Gajbhiye

2002-01-01

368

Geomorphological characterization of endorheic basins in northern Chile  

NASA Astrophysics Data System (ADS)

Quantitative geomorphology regroups a large number of interesting tools to characterize natural basins across scales. The application of these tools to several river basins allows the description and comparison of geomorphological properties at different spatial scales as oppose to more traditional descriptors that are typically applied at a single scale, meaning the catchment scale. Most of the recent research using these quantitative geomorphological tools has focused on open catchments and no specific attention has been given to endorheic basins, and the possibility of having particular features that distinguish them from exorheic catchments. The main objective of our study is to characterize endorheic basins and investigate whether these special geomorphological features can be identified. Because scaling invariance is a widely observed and relatively well quantified property of open basins, it provides a suitable tool to characterize differences between the geomorphology of closed and open basins. Our investigation focuses on three closed basins located in northern Chile which describe well the diversity in the geomorphology and geology of this arid region. Results show that endhoreic basins exhibit different slope-area and flow paths sinuosity regimes compared to those observed in open basins. These differences are in agreement with the particular self-similar behavior across spatial scales of the Euclidean length of subcatchments, as well as the Hack's law and Horton's ratios. These regimes imply different physical processes inside the channel network regardless of the basin area, and they seem to be related to the endorheic character of these basins. The analysis of the probability density functions of contributing areas and lengths to the lower region shows that the hypothesis of self-similarity can also be applied to closed basins. Theoretical expressions for these distributions were derived and validated by the data. Future research will focus on (1) applying similar analyses in other locations and comparing the results, and (2) understanding and modeling the effects of groundwater in forming the landscape of these arid regions.

Dorsaz, J.; Gironas, J. A.; Escauriaza, C. R.; Rinaldo, A.

2011-12-01

369

Provenance of alluvial fan deposits to constrain the mid-term offsets along a strike-slip active fault: the Elsinore fault in the Coyote Mountains, Imperial Valley, California.  

NASA Astrophysics Data System (ADS)

The lateral variation in rates along a fault and its constancy along time is a matter of discussion. To give light to this discussion, short, mid and long term offset distribution along a fault is needed. Many studies analyze the short-term offset distribution along a strike-slip fault that can be obtained by the analysis of offset features imprinted in the morphology of the near-fault area. We present an example on how to obtain the mid- to long-term offset values based on the composition of alluvial fans that are offset by the fault. The study area is on the southern tip of the Elsinore fault, which controls the mountain front of the Coyote Mountains (California). The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system, extending 250 km from the Los Angeles Basin southeastward into the Gulf of California, in Mexico. The slip-rate on the southern Elsinore fault is believed to be moderate based on recent InSAR observations, although a recent study near Fossil Canyon (southern Coyote Mountains) suggests a rate in the range of 1-2 mm/yr. For this study we processed the airborne LiDAR dataset (EarthScope Southern & Eastern California, SoCal) to map short to mid-term alluvial offsets. We reprocessed the point clouds to produce DEMs with 0.5m and 0.25m grids and we varied the insolation angles to illuminate the various fault strands and the offset features. We identified numerous offset features, such as rills, channel bars, channel walls, alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to 350 m. For the mid- to long-term offsets of the alluvial fans we benefited from the diverse petrological composition of their sources. Moreover, we recognized that older alluvium, which is offset by greater amounts, is in some cases buried beneath younger alluvial fan deposits and separated by buried soils. To determine the source canyon of various alluvial elements, we quantified the clast assemblage of each source basin and each alluvial fan on both sides of the fault. To accomplish this, we used a portable grid and classified more than 300 clasts at each of more than 90 sites along the fault. We found a very good fit between displaced alluvial fan elements and their inferred source canyons, but a poor match with the alluvium from neighboring canyons, which allows us to resolve the long-term offset. Planned dating of the pedogenic carbonate associated with these buried soils will allow the resolution of the mid- to long-term slip rates over multiple time frames to test the constancy of fault slip rate during the late Quaternary, as well as to test the lateral variations in rate along the fault.

Masana, Eulalia; Stepancikova, Petra; Rockwell, Thomas

2013-04-01

370

Debris-flow deposits in an alluvial-plain succession: The upper Triassic Callide coal measures of Queensland, Australia  

SciTech Connect

The Carnian-Rhaetian Callide Coal Measures are preserved in a small (22.5 km by 8 km), partially fault-bounded basin remnant in east-central Queensland, Australia. The <150 m thick coal-measure succession is interpreted to have accumulated during a phase of mild crustal extension that formed a series of discrete, intermontane basins in eastern Australia. The succession fines upward from a conglomerate-rich lower part into a finer-grained and coal-bearing upper section (including coal seams <34 m thick), and is interpreted as the deposits of an alluvial-plain environment. Anomalous, matrix-rich diamictites, breccias, and conglomerates have been recognized within the succession at several localities, in many cases interbedded with coals. These are interpreted as the product of debris flows. Two debris-flow lithofacies are recognized: (1) mixtures of fine carbonaceous material, clay, silt, sand, gravel, and volcaniclastic debris, and (2) breccias consisting principally of coal clasts in a coaly matrix with minor clastic and volcaniclastic debris. The distribution of debris flows in the Callide Coal Measures shows a coincidence with mapped faults and interpreted structural lineaments. The debris flows may have been triggered by fault movements, which formed rupture topography on the flat alluvial plain, and caused destabilization of water-saturated clastic and organic sediments. Some debris-flow bodies may have been mounded, such that subsequent peat formation was restricted until those bodies were buried. The preservation of debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow units at different stratigraphic levels along mapped structures suggests multiple paleoseismic events or multiple debris-flow events along those structures. The mixing of volcaniclastic debris into debris-flow facies suggests that seismic events were coincident with (or perhaps caused by) nearby, explosive volcanic activity. The close relationship between debris-flow deposits and thick coal bodies on the inferred downthrown sides of faults at Callide further suggests that periodic, tectonic subsidence may have facilitated thick coal accumulation.

Jorgensen, P.J.; Fielding, C.R. [Univ. of Queensland, Brisbane (Australia). Dept. of Earth Sciences

1999-09-01

371

Geotechnical mapping for alluvial fan deposits controlled by active faults: a case study in the Erzurum, NE Turkey  

NASA Astrophysics Data System (ADS)

Erzurum, the biggest city of Eastern Anatolia Region in the Turkey, is located in Karasu Plain. Karasu Plain, located on the central segment of the Erzurum Fault Zone, is an intermountain sedimentary basin with a Miocene-Quaternary volcanic basement, andesitic-basaltic lava flows and fissure eruptions of basaltic lava. It was filled in the early Quaternary by lacustrine fan-delta deposits. The basin is characterized by NNE-SSW trending sinistral wrench faults on its eastern margin and ENE-WSW trending reverse faults on its southern margin. Both systems of active faults intersect very near to Erzurum, which is considered to be the most likely site for the epicenter of a probable future large earthquake. Historical records of destructive earthquakes, morphotectonic features formed by paleo-seismic events and instrument seismic data of region indicate to a very high regional seismicity. The residential areas of Erzurum are located on thick alluvial fan deposits forming under the control of faults on the central segment of the Erzurum Fault Zone, which is one of the most active fault belts of the East Anatolian Region. Over time, the housing estates of city such as Yenisehir and Yildizkent have been expanded toward to the west and southwest part of Erzurum as a consequence of rapid and massive construction during the last 30 years. Geotechnical investigation has therefore been undertaken the residential areas of city in order to characterize geotechnical properties over the varied lithologies examine the potential for geotechnical mapping and assess the foundation conditions of the present and future settlement areas. The geological field observations and operations have been performed to make the soil sampling and characterize the lateral and vertical changes in thickness of the alluvial deposits in trenches, excavations and deep holes with 6-12 m sections. The soil samples have been subjected to a series of tests under laboratory conditions to obtain physical and mechanical properties. Furthermore, the standard penetration tests have been applied to the soils under field conditions. The geological field observations, geotechnical data and distribution of bearing capacity have been considered for the geotechnical mapping. Based on the geotechnical map, there are five geotechnical zones distinguished in the study area.

Yarbasi, Necmi; Kalkan, Ekrem

2009-08-01

372

Basin analysis of tertiary strata in the Pattani Basin, Gulf of Thailand  

SciTech Connect

The stratigraphic and structural evolution of the Pattani basin, the most prolific petroleum basin in Thailand, reflects the extensional tectonics of continental southeast Asia. East-west extension, a product of the northward collision of India with Eurasia since the early Tertiary resulted in the formation of a series of north-south-trending sedimentary basins including the Pattani basin. Subsidence and thermal histories of the basin can generally be accounted for by nonuniform lithospheric stretching. The validity of nonuniform lithospheric stretching as a mechanic for the formation of the Pattani basin is confirmed by a reasonably good agreement between modeled and observed vitrinite reflectance at various depths and locations. The amount of stretching and surface heat flow generally increases from the basin margin to the basin center. Crustal stretching factor ([beta]) ranges from 1.3 at the basin margin to 2.8 in the center. Subcrustal stretching factor ([sigma]) ranges from 1.3 at the margin to more than 3.0 in the center. The stretching of the lithosphere may have extended basement rocks as much as 45 to 90 km and may have caused the upwelling of asthenosphere, resulting in high heat flow. The sedimentary succession in the Pattani basin is divisible into synrift and postrift sequences. The synrift sequences comprise (1) late Eocene ( ) to early Oligocene alluvial fan, braided river, and flood-plain deposits; (2) late Oligocene to early Miocene floodplain and channel deposits; and (3) an early Miocene regressive package of marine to nonmarine sediments. Deposition of synrift sequences corresponded to rifting and extension, which included episodic block faulting and rapid subsidence. Postrift succession comprises (1) an early to middle Miocene regressive package of shallow marine to nonmarine sediments, (2) a late early Miocene transgressive package; and (3) a late Miocene to Pleistocene transgression succession.

Chonchawalit, A. (PTT Exploration and Production Public Co., Ltd., Bangkok (Thailand)); Bustin, R.M. (Univ. of British Columbia, Vancouver (Canada))

1994-07-01

373

Geogenic arsenic in groundwaters from Terai Alluvial Plain of Nepal  

NASA Astrophysics Data System (ADS)

The origin and mobility of arsenic (As) in the groundwater environment has received serious attention in recent years. Recent studies have reported naturally occurring As in groundwaters of the Terai Alluvial Plains (TAP) in southern Nepal, where groundwater exploitation has increased since the 1960s. The source of As in TAP is geogenic and leached primarily due to weathering of As bearing rocks and sediments in the Himalayas. In our present study, we have investigated the groundwater chemistry in the central part of the TAP in Nawalparasi district. TAP groundwaters are near-neutral to alkaline, with predominantly reducing character and high HCO3^- low SO^{2-}_4 and NO3^- concentrations. Elevated HCO3 levels possibly result due to the oxidation of organic matter, low SO4^{2-} levels reflect sulfate reduction. Elevated NH4^+ concentrations in these groundwaters suggest dissimilatory nitrate reduction in the aquifers. Total arsenic (Astot) levels in groundwater varied from 1.7 ?g/L to as high as 404 ?g/L with dominance of As (III) species and elevated levels of dissolved Fe and Mn. Arsenic is mobilized in groundwaters as a result of desorption of As-oxyanions adsorbed onto Fe-and Mnoxides as well as reductive dissolution of these surface reactive phases from the sediments along with release ouf as in anoxie groundwaters.

Bhattacharya, P.; Tandukar, N.; Nekul, A.; Valero, A. A.; Mukherjee, A. B.; Jacks, G.

2003-05-01

374

Biodegradation of Petroleum Hydrocarbon Vapors In Unsaturated Alluvial Sand  

NASA Astrophysics Data System (ADS)

Biodegradation rates are critical parameters in models aimed at predicting the nat- ural attenuation of volatile organic compounds (VOCs) in the unsaturated zone. In this study the kinetic rate laws for the aerobic biodegradation of selected petroleum hydrocarbons and MTBE were investigated in unsaturated alluvial sand exposed to the vapors from a fuel mixture. Laboratory column and batch experiments were per- formed at room temperature under aerobic conditions. An analytical reactive transport model for VOC vapors in soil based on Monod kinetics is used for data interpretation. In the column experiment, steady-state diffusive vapor transport was reached after 23 days. Monod kinetic parameters were derived from the column profiles for toluene, m-xylene, octane and hexane. The degradation of cyclic alkanes, isooctane, and 1,2,4- trimethylbenzene was best described by first-order kinetics. MTBE, pentane and chlo- rofluorocarbons were recalcitrant. Batch experiments suggested first-order disappear- ance rate laws for all VOCs except octane, which followed zero-order kinetics. For some compounds including MTBE, disappearance rates in abiotic batch experiments were as high as in live batches. Abiotic disappearance is explained by slow intraparti- cle diffusion and sorption. It is concluded that the column approach is preferable for determining biodegradation rate parameters to be used in risk assessment models.

Höhener, P.; Duwig, C.; Pasteris, G.; Dakhel, N.; Kaufmann, K.; Werner, D.

375

Biology of Annual Plants in Arid and Semi-Arid Desert Regions of China  

Microsoft Academic Search

\\u000a Annual species are a major component of desert vegetation, with their unique traits playing a key role in vegetation restoration\\u000a in arid and semi-arid deserts. This chapter presents a systematic discussion of current research status and expectations of\\u000a future studies with respect to annual species in the deserts of China. To date, studies on annual species have been concerned\\u000a mainly

Xuehua Li

376

Broadscale mappingof temporary wetlands in arid Australia  

Microsoft Academic Search

We describe a robust methodology to detect and estimate the size of temporary wetlands usingAVHRR satellite data within larg e areas (10 6 km2) of the arid zone. The methodology uses spectral matchingand exclusion of salt surfaces to discriminate between water and non- water surfaces. The status of 115 lakes was used to evaluate the methodology. A classification accuracy of

D. A. Roshier; R. M. Rumbachs

377

Seeding Native Grasses in the Arid Southwest.  

National Technical Information Service (NTIS)

Grass seeding is an uncertain endeavor even in the best of circumstances, but in the arid Southwest it is an extremely risky venture. This technical note is intended to present the important factors that influence the success of seeding native grasses in ...

D. R. Dreesen

2013-01-01

378

Evaporation Modeling in Lakes in Arid and Semi-arid Regions  

NASA Astrophysics Data System (ADS)

Evaporation is the main loss from the system but, in contrast to losses to the groundwater, the evaporative loss does not have any direct benefits in the immediate environment of the reservoir. Evaporative losses make small reservoirs less efficient than large reservoirs. Significance of its accurate estimation increases when the problems are associated with the water resources accounting of arid and semi-arid regions. Direct measurement of evaporation from water surface is very difficult. The process of evaporation is a complex phenomenon, which is a function of solar radiation, temperature, wind speed, vapour pressure deficit, atmospheric pressure and the surrounding environment. Accurate estimation of evaporation is important for designing and planning projects in which a water balance is key factor as well as for conservation of water. In other words, accurate estimation of free water surface evaporation in arid and semi-arid regions, what criterion can be followed for selection of reliable evaporation method, is an important area of research. The precise estimation of evaporation from a water body requires extensive databases, which are often missing and/or expensive to generate on routine basis. In this paper, different methods for evaporation from small lakes in arid and semi-arid regions(According to the available data) is considered and different parameters affected this phenomenon are discussed(i.e. wind speed above the water surface, heat storage of lake, roughness length of water surface, etc.).

Abbasi, A.; Giesen, N.

2012-04-01

379

Topsoil moisture patterns in arid and semi-arid hillslopes as related to shrubs  

NASA Astrophysics Data System (ADS)

The topsoil moisture distribution is a key factor in understanding eco-geomorphic processes in arid and semi-arid hillslopes. Remotely sensed thermal infrared data acquired by a ground-based platform were used for high-spatially detailed measurement of the temporal changes of the topsoil moisture contents in arid and semi-arid sites in Israel. The results highlight the effect of native shrubs on the soil moisture content, distribution, and dynamics during desiccation following runoff events. At the shrub scale, there was a general spatio-temporal pattern of topsoil moisture behavior manifested as a dynamic moist patch and controlled by pedo-hydrological properties, hillslope aspect, and micro-topography. At the hillslope scale, the areas of higher soil moisture at the end of runoff events are closely associated with the vegetation pattern. The topsoil moisture dynamics indicate patchiness in the hydrological response of arid and semi-arid hillslopes to rainfall events, and thereby improve our understanding of the mosaic-like patterns of source and sink areas for runoff and sediments in these systems.

Katra, I.

2009-04-01

380

Cambrian to Devonian evolution of alluvial systems: The sedimentological impact of the earliest land plants  

NASA Astrophysics Data System (ADS)

In present-day alluvial environments, the impact of vegetation on sedimentological processes and deposits is well known. A vegetated catchment may decrease sediment yield, sediment erodibility, Hortonian overland flow, aeolian winnowing of fines, the proportion of sediment transported as bedload, and may increase bank stability, infiltration into substrates, and bed roughness. Vegetation also promotes the production of chemically-weathered clays and soils and the adoption of a meandering style. It is generally understood that, prior to the evolution of terrestrial vegetation during the Early Palaeozoic, ancient alluvial systems were markedly different from modern systems, with many systems adopting a "sheet-braided" style. This understanding has previously informed the interpretations of many Precambrian pre-vegetation alluvial successions, but there has been relatively little work regarding Early Palaeozoic alluvial successions laid down prior to and during the initial colonization of the Earth's surface by plants. A comprehensive review of 144 Cambrian to Devonian alluvial successions documented in published literature was combined with original field data from 34 alluvial successions across Europe and North America. The study was designed to identify changes in alluvial style during the period that vegetation was evolving and first colonizing alluvial environments. An increase in mudrock proportion and sandstone maturity is apparent, along with a decrease in overall sand grain size through the Early Palaeozoic. These trends suggest that primitive vegetation cover promoted the production and preservation of muds from the mid Ordovician onwards and increased the residence time of sand-grade sediment in alluvial systems. The compilation also enables the first stratigraphic occurrence of certain vegetation-dependent sedimentary features to be pinpointed and related to the evolution of specific palaeobotanical adaptations. The first markedly heterolithic alluvial sequences appeared at about the same time as the most primitive terrestrial vegetation in the Ordovician, and prolific pedogenic calcite, charcoal and bioturbated floodplain fines first appeared in the rock record at about the same time as vascular-plant macrofossils became abundant in the late Silurian. Lateral accretion sets in channel deposits appeared near the Silurian-Devonian boundary, at or shortly before the appearance of underground rooting systems, and become progressively more abundant in the record during the Devonian, implying a major expansion of meandering rivers as rooted plants stabilized river banks. Coals become abundant after the development of plant arborescence. The analysis suggests that the evolution of embryophytes had a profound effect on fluvial processes and deposits, and this period of landscape evolution must be considered amongst the most significant environmental and geomorphological changes in Earth history, with profound consequences for all aspects of the Earth system.

Davies, Neil S.; Gibling, Martin R.

2010-02-01