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Sample records for river meander migration

  1. RVR MeanderMigration of meandering rivers in homogeneous and heterogeneous floodplains using physically-based bank erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The RVR Meander platform for computing long-term meandering-channel migration is presented, together with a method for planform migration based on the modeling of the streambank erosion processes of hydraulic erosion and mass failure. An application to a real-world river, with assumption of homogene...

  2. Net local removal of floodplain sediment by river meander migration

    NASA Astrophysics Data System (ADS)

    Lauer, J. Wesley; Parker, Gary

    2008-04-01

    Erosion from the banks of meandering rivers causes a local influx of sediment to the river channel. Most of the eroded volume is usually replaced in nearby point bars. However, the typical geometry of river bends precludes the local replacement of all eroded material because (i) point bars tend to be built to a lower elevation than cutbanks and (ii) point bars tend to be shorter than the eroding portion of cutbanks because of channel curvature. In a floodplain that is in equilibrium (i.e., neither increasing nor decreasing in volume), sediment eroded from cut banks must be replaced elsewhere on the floodplain. The local imbalance caused by differences in bank height should be balanced primarily by overbank deposition, while the local imbalance caused by curvature should be balanced primarily by deposition in abandoned stream courses or oxbow lakes. Estimates of these local imbalances based on remotely sensed measurements of bank geometry and channel migration have been made on four systems in the United States: a 91-km reach of the Pearl River in Louisiana and Mississippi, a 62-km reach of the Bogue Chitto River in Louisiana, a 35-km reach of the Neuse River in North Carolina, and a 2.7-km reach of the Vermillion River in Minnesota. For these systems, the total local imbalance, integrated over many bends, ranged from 0.36 to 2.27 m 3/yr/m of valley length (0.15 to 1.32 m 3/yr/m of channel length), or 7 to 45% of gross cutbank erosion, with a typical value of about 17%. When compared with gauged suspended sediment data, the measurements provide estimates of the relative importance of floodplains for storing material transported by a river system. The data suggest that even if the studied systems are near long-term mass balance equilibrium (as opposed to undergoing net deposition or erosion), almost all of the sand and in some cases much of the silt and clay in transit through these systems is likely to have spent some time stored in an upstream floodplain.

  3. Self-formed meandering river created in the laboratory using an upstream migrating boundary

    NASA Astrophysics Data System (ADS)

    van Dijk, W. M.; van de Lageweg, W. I.; Kleinhans, M. G.

    2010-12-01

    Braided rivers are relatively easily formed in the laboratory, whereas self-formed meandering rivers in the lab have proven very difficult to form, indicating a lack of understanding of the necessary and sufficient conditions for meandering. Our objective is to create self-formed dynamic meandering rivers and floodplains in a laboratory. Early experiments attempted to initiate meandering with upstream inflow at a fixed angle different from the general flow direction. The resulting bends were fixed at one position, which is not the dynamic meandering observed in nature. Another important condition for meandering is to have banks stronger than the non-cohesive bed sediment, which has been attained by growing vegetation. Furthermore, finer or light-weight sediment has been used to let chute channels fill up where otherwise multi-thread channels would have evolved, which is braiding. Yet the fixed-angle inflow kept meander migration and channel belt width and complexity limited. We accomplished dynamic meandering in the laboratory by using an upstream migrating boundary, which simulates a meander migrating into the flume. Our experiments were conducted in a circulated flume of 11x6 meter, with a constant discharge and sediment feed consisting of a sediment mixture ranging from silt to fine gravel (Kleinhans et al., 2010, this conference). The downstream boundary is a lake into which the river built a branched fan delta (Van de Lageweg et al., 2010, this conference). The morphology was recorded by high-resolution (0.5 mm) line-laser scanning and digital Single Lens Reflex (SLR) camera used for channel-floodplain segmentation and particle size estimation, at an interval of 8 hours. Furthermore a large number of smaller-scale auxiliary experiments were conducted to explore meandering tendency in a large range of parameters. Initial alternate ‘forced’ bars were formed at fixed positions with low sinuosity when the upstream boundary was at one fixed position. Migration

  4. River meandering dynamics.

    PubMed

    Edwards, Boyd F; Smith, Duane H

    2002-04-01

    The Ikeda, Parker, and Sawai river meandering model is reexamined using a physical approach employing an explicit equation of motion. For periodic river shapes as seen from above, a cross-stream surface elevation gradient creates a velocity shear that is responsible for the decay of small-wavelength meander bends, whereas secondary currents in the plane perpendicular to the downstream direction are responsible for the growth of large-wavelength bends. A decay length D=H/2C(f) involving the river depth H and the friction coefficient C(f) sets the scale for meandering, giving the downstream distance required for the fluid velocity profile to recover from changes in the channel curvature. Using this length scale and a time scale T, we explicitly trace the observed length scale invariance to the equations of motion, and predict similar time and velocity scale invariances. A general time-dependent nonlinear modal analysis for periodic rivers reveals that modes higher than the third mode are needed to describe upstream migration of bend apexes just before oxbow cutoff, and are important to accurate calculations of the time and sinuosity at cutoff. PMID:12006009

  5. River Meander Studies

    NASA Technical Reports Server (NTRS)

    Schubert, G.; Lingenfelter, R.

    1971-01-01

    The feasibility of using satellite television photography of geomorphological indices to obtain a correlation between a stream meander power spectrum and stream discharge frequency distribution is considered. Water resources assessment includes information on the average rainfall over large drainage basins and calculations relating flow measurements to geographical areas. Photoelectric optical scanning techniques provide a digitized procedure for locating and following river meander curve points.

  6. Modification of meander migration by bank failures

    NASA Astrophysics Data System (ADS)

    Motta, D.; Langendoen, E. J.; Abad, J. D.; García, M. H.

    2014-05-01

    Meander migration and planform evolution depend on the resistance to erosion of the floodplain materials. To date, research to quantify meandering river adjustment has largely focused on resistance to erosion properties that vary horizontally. This paper evaluates the combined effect of horizontal and vertical floodplain material heterogeneity on meander migration by simulating fluvial erosion and cantilever and planar bank mass failure processes responsible for bank retreat. The impact of stream bank failures on meander migration is conceptualized in our RVR Meander model through a bank armoring factor associated with the dynamics of slump blocks produced by cantilever and planar failures. Simulation periods smaller than the time to cutoff are considered, such that all planform complexity is caused by bank erosion processes and floodplain heterogeneity and not by cutoff dynamics. Cantilever failure continuously affects meander migration, because it is primarily controlled by the fluvial erosion at the bank toe. Hence, it impacts migration rates and meander shapes through the horizontal and vertical distribution of erodibility of floodplain materials. Planar failures are more episodic. However, in floodplain areas characterized by less cohesive materials, they can affect meander evolution in a sustained way and produce preferential migration patterns. Model results show that besides the hydrodynamics, bed morphology and horizontal floodplain heterogeneity, floodplain stratigraphy can significantly affect meander evolution, both in terms of migration rates and planform shapes. Specifically, downstream meander migration can either increase or decrease with respect to the case of a homogeneous floodplain; lateral migration generally decreases as result of bank protection due to slump blocks; and the effect on bend skewness depends on the location and volumes of failed bank material caused by cantilever and planar failures along the bends, with possible achievement of

  7. CLASSIFICATION AND BEHAVIOR OF MEANDER MIGRATION.

    USGS Publications Warehouse

    Martin, Edward H.; Shen, Hsieh W.; Glover, J. Ed

    1986-01-01

    Meander migrations on the Mississippi River between Cairo, Illinois and Baton Rouge, Louisiana for the time period between the years 1765 and 1930 were classified into six categories based on the nature of channel movements. During the time period between 1765 and 1900, man's disturbance on this river reach was relatively minor. This study was mainly based on measurements taken in the years 1765, 1825, 1887 and 1930. The six categories of meander migration were: downstream limb migration, downstream limb rotation, mainly upstream limb migration, upstream limb rotation, pure translation and pure expansion. It was determined that over 60% of future meander migrations could be predicted from the characteristics of each individual initial channel pattern.

  8. Valley evolution by meandering rivers

    NASA Astrophysics Data System (ADS)

    Limaye, Ajay Brian Sanjay

    Fluvial systems form landscapes and sedimentary deposits with a rich hierarchy of structures that extend from grain- to valley scale. Large-scale pattern formation in fluvial systems is commonly attributed to forcing by external factors, including climate change, tectonic uplift, and sea-level change. Yet over geologic timescales, rivers may also develop large-scale erosional and depositional patterns that do not bear on environmental history. This dissertation uses a combination of numerical modeling and topographic analysis to identify and quantify patterns in river valleys that form as a consequence of river meandering alone, under constant external forcing. Chapter 2 identifies a numerical artifact in existing, grid-based models that represent the co-evolution of river channel migration and bank strength over geologic timescales. A new, vector-based technique for bank-material tracking is shown to improve predictions for the evolution of meander belts, floodplains, sedimentary deposits formed by aggrading channels, and bedrock river valleys, particularly when spatial contrasts in bank strength are strong. Chapters 3 and 4 apply this numerical technique to establishing valley topography formed by a vertically incising, meandering river subject to constant external forcing---which should serve as the null hypothesis for valley evolution. In Chapter 3, this scenario is shown to explain a variety of common bedrock river valley types and smaller-scale features within them---including entrenched channels, long-wavelength, arcuate scars in valley walls, and bedrock-cored river terraces. Chapter 4 describes the age and geometric statistics of river terraces formed by meandering with constant external forcing, and compares them to terraces in natural river valleys. The frequency of intrinsic terrace formation by meandering is shown to reflect a characteristic relief-generation timescale, and terrace length is identified as a key criterion for distinguishing these

  9. Quantifying process-based mitigation strategies in historical context: separating multiple cumulative effects on river meander migration.

    PubMed

    Fremier, Alexander K; Girvetz, Evan H; Greco, Steven E; Larsen, Eric W

    2014-01-01

    Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a 'sliding baseline'. In river systems, cumulative effects caused by flow regulation, channel revetment and riparian vegetation removal significantly impact floodplain ecosystems by altering channel dynamics and precluding subsequent ecosystem processes, such as primary succession. To quantify these impacts on floodplain development processes, we used a model of river channel meander migration to illustrate the degree to which flow regulation and riprap impact migration rates, independently and synergistically, on the Sacramento River in California, USA. From pre-dam conditions, the cumulative effect of flow regulation alone on channel migration is a reduction by 38%, and 42-44% with four proposed water diversion project scenarios. In terms of depositional area, the proposed water project would reduce channel migration 51-71 ha in 130 years without current riprap in place, and 17-25 ha with riprap. Our results illustrate the utility of a modeling approach for quantifying cumulative impacts. Model-based quantification of environmental impacts allow scientists to separate cumulative and synergistic effects to analytically define mitigation measures. Additionally, by selecting an ecosystem process that is affected by multiple impacts, it is possible to consider process-based mitigation scenarios, such as the removal of riprap, to allow meander migration and create new floodplains and allow for riparian vegetation recruitment.

  10. Quantifying process-based mitigation strategies in historical context: separating multiple cumulative effects on river meander migration.

    PubMed

    Fremier, Alexander K; Girvetz, Evan H; Greco, Steven E; Larsen, Eric W

    2014-01-01

    Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a 'sliding baseline'. In river systems, cumulative effects caused by flow regulation, channel revetment and riparian vegetation removal significantly impact floodplain ecosystems by altering channel dynamics and precluding subsequent ecosystem processes, such as primary succession. To quantify these impacts on floodplain development processes, we used a model of river channel meander migration to illustrate the degree to which flow regulation and riprap impact migration rates, independently and synergistically, on the Sacramento River in California, USA. From pre-dam conditions, the cumulative effect of flow regulation alone on channel migration is a reduction by 38%, and 42-44% with four proposed water diversion project scenarios. In terms of depositional area, the proposed water project would reduce channel migration 51-71 ha in 130 years without current riprap in place, and 17-25 ha with riprap. Our results illustrate the utility of a modeling approach for quantifying cumulative impacts. Model-based quantification of environmental impacts allow scientists to separate cumulative and synergistic effects to analytically define mitigation measures. Additionally, by selecting an ecosystem process that is affected by multiple impacts, it is possible to consider process-based mitigation scenarios, such as the removal of riprap, to allow meander migration and create new floodplains and allow for riparian vegetation recruitment. PMID:24964145

  11. Quantifying Process-Based Mitigation Strategies in Historical Context: Separating Multiple Cumulative Effects on River Meander Migration

    PubMed Central

    Fremier, Alexander K.; Girvetz, Evan H.; Greco, Steven E.; Larsen, Eric W.

    2014-01-01

    Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a ‘sliding baseline’. In river systems, cumulative effects caused by flow regulation, channel revetment and riparian vegetation removal significantly impact floodplain ecosystems by altering channel dynamics and precluding subsequent ecosystem processes, such as primary succession. To quantify these impacts on floodplain development processes, we used a model of river channel meander migration to illustrate the degree to which flow regulation and riprap impact migration rates, independently and synergistically, on the Sacramento River in California, USA. From pre-dam conditions, the cumulative effect of flow regulation alone on channel migration is a reduction by 38%, and 42–44% with four proposed water diversion project scenarios. In terms of depositional area, the proposed water project would reduce channel migration 51–71 ha in 130 years without current riprap in place, and 17–25 ha with riprap. Our results illustrate the utility of a modeling approach for quantifying cumulative impacts. Model-based quantification of environmental impacts allow scientists to separate cumulative and synergistic effects to analytically define mitigation measures. Additionally, by selecting an ecosystem process that is affected by multiple impacts, it is possible to consider process-based mitigation scenarios, such as the removal of riprap, to allow meander migration and create new floodplains and allow for riparian vegetation recruitment. PMID:24964145

  12. The Origin of River Meanders

    NASA Astrophysics Data System (ADS)

    Sahagian, D. L.; Chatanantavet, P.; Bradley, C.; Friedgen-Veitch, D.; Diplas, P.

    2015-12-01

    Various propositions for the origin of meanders have been suggested in the past, involving local disturbances such as variable bank material, obstructions to flow, and sediment transport. Each of these approaches has required a very special and complex set of circumstances for the onset of meandering. However, meanders have also been observed in other systems such as the gulf stream , window glass , glacial meltwater, channels in submarine fans, the jet stream, water faucets, and many others. What has not been satisfactorily demonstrated is why some rivers (or parts of rivers) should tend to meander in the first place rather than ply a straight course to base level. We suggest that the fundamental cause of the river meander instability is simply a minimization of power (rate of work done), with an onset that occurs when inertial terms exceed body forces (e.g. gravity) acting on the flow, and thus create an adverse pressure gradient directed in the opposite direction of the flow. A simple way to visualize the cause of the instability is that the water "backs up" upon itself, running into a parcel of water downstream that is flowing more slowly than the water upstream. This causes the direction of maximum local water surface slope to be diverted to one side or the other of the regional slope. This can occur when a river encounters the ocean (or a lake, or a break in slope), and can occur in many other situations as well. We analyzed various meandering systems globally, and conducted laboratory experiments under controlled conditions to determine the conditions necessary for the onset of the meander instability. The results indicate that the meander instability does not depend on sediment or erodible banks. The critical threshold for the onset of the meander instability occurs when inertial forces exceed body forces acting on the fluid such that an adverse pressure gradient arises. Better understanding of the meander instability should thus elucidate some of the

  13. Meander dynamics in a changing river corridor

    NASA Astrophysics Data System (ADS)

    Magdaleno, Fernando; Fernández-Yuste, José A.

    2011-07-01

    In the first decades of the twentieth century, the Ebro River was the Iberian channel with the most active fluvial dynamics and the most remarkable spatial-temporal evolution. Its meandering typology, the dimensions of its floodplain (with an average width > 3.0 km), and the singularities of its flow regime produced a especially interesting set of river functions from the perspective of the fluvial geomorphology of the largest Mediterranean channels. The largest dynamics of the Ebro River are concentrated along the meandering profile of the central sector. During the twentieth century, this sector experienced a large alteration of its geomorphological structure. We present here an analysis of this evolution through the cartographic study of a long segment of the river (~ 250 km) in 1927, 1956, and 2003. The study is focused on a wide set of geomorphic parameters and indicators that represent the forms of the meander belt, its lateral dynamics, and the overall mobility of the river corridor. The results of the analysis show a large transformation of the meander dynamics, as well as a massive loss of the river lateral activity, most of which occurred in the second half of the twentieth century. This intense geomorphological transformation becomes visible in (i) the large reduction of the bankfull width and the active channel area; (ii) the decrease in the rate of lateral channel migration; (iii) the loss of channel activity; and (iv) the large reduction of coincidence of the active channel areas. However, the most traditional form parameters (i.e., wavelength, amplitude, radius of curvature, and meander length) do not show significant differences throughout the time interval analysed. The study reinforces the necessity of integrating a wide range of dynamic indicators, which may complement the classical form parameters and represent the real functioning of the river corridor, in the geomorphological analyses of meander dynamics. This work also shows the most

  14. Numerical Simulations of Floodplain Heterogeneity Effects on Meanders Migration

    NASA Astrophysics Data System (ADS)

    Bogoni, M.; Lanzoni, S.; Putti, M.

    2014-12-01

    Floodplains and sinuous rivers have a close relationship with each other, mutually influencing their evolutions in time and space. The heterogeneity in erosional resistance has a crucial role on meander planform evolution. It depends on external factors, like land use and cover, but also on the composition of the floodplain, which is due to the ancient geological composition and to the processes associated to long-term river migration. In particular, banks erosion and deposition cause a variation of the superficial composition of the soil, therefore the river patterns are influenced by the previous trends. Based on some recent works, the aim of this contribution is to collect numerical information on the relations between meander migration and the heterogeneity of floodplains caused by oxbow lakes. Numerical simulations have been performed to analyze the temporal and spatial behavior of meanders with a range of values of the erosional resistance of the plain. These values are set as a function of some factors: the characteristic grain size of sediment transported by the flow, the deposition age of the sediments, the eventual presence of vegetation on the banks. The statistical analysis of characteristic geometrical quantities of meanders are able to show the dependence of the simulation results on the meander history. In particular we try to answer to the following questions: how do the rivers affect themselves during their spatial and temporal evolution, modifying the distribution of the floodplain erodibility? Do the migration history plays a main role on the meanders migration modeling?

  15. Characterization and prediction of meandering channel migration in the GIS environment: a case study of the Sabine River in the USA.

    PubMed

    Heo, Joon; Duc, Trinh Anh; Cho, Hyung-Sik; Choi, Sung-Uk

    2009-05-01

    This study focused on the prediction of a 22 km meandering channel migration of the Sabine River between the states of Texas and Louisiana. The meander characteristics of 12 bends, identified from seven orthophotos taken between 1974 and 2004, were acquired in a GIS environment. Based on that earlier years' data acquisition, channel prediction was performed for the two years 1996 and 2004 using least squares estimation and linear extrapolations, yielding a satisfactory agreement with the observations (the median predicted and observed migration rates were 3.1 and 3.6 [m/year], respectively). The best-predicted migration rate was found to be associated with the longest orthophoto-recorded interval. The study confirmed that channel migration is strongly correlated with bend curvature and that the maximum migration rate of the bend corresponded to a radius of curvature [bend radius (R(C))/channel width (W(C))] of 2.5. In tight bends of a smaller radius of curvature than 1.6, secondary flow scouring near the bend apex increases bend curvature. The stability index of the dimensionless bend radius was determined to be 2.45. Overall, this study proves the effectiveness of least squares estimation with historical orthophotography for characterization of meandering channel migration.

  16. A chaos model of meandering rivers

    SciTech Connect

    Stoelum, H.H.

    1991-03-01

    A meandering river is a nonlinear dynamic system, and fractal geometry describes well the meander bends of such rivers. Based on a qualitative, sedimentological model of the process of meandering, a chaos model is proposed, describing meandering as the outcome of two processes: the feedback interaction between river curvature and a high-velocity thalweg channel within the river; and the interaction between meander bends causing abandonment and straightening of the river course. The system, when initiated from a nearly straight river course, moves toward a dynamic equilibrium in which the meander bends are fractal. This development is a case of self-organized criticality. The equilibrium represents a state of optimal energy dissipation in a situation where two counteracting processes are balancing each other. Sedimentology may be seen as the science that describes how nonlinear dynamic processes interact to create a depositional system. As indicated by the example of meandering rivers, the use of chaos and fractal models may give sedimentology a new turn toward understanding sedimentary processes and the 3-D architecture of sediment bodies.

  17. Biomorphodynamic modelling of inner bank advance in migrating meander bends

    NASA Astrophysics Data System (ADS)

    Zen, Simone; Zolezzi, Guido; Toffolon, Marco; Gurnell, Angela M.

    2016-07-01

    We propose a bio-morphodynamic model at bend cross-sectional scale for the lateral migration of river meander bends, where the two banks can migrate separately as a result of the mutual interaction between river flow, sediments and riparian vegetation, particularly at the interface between the permanently wet channel and the advancing floodplain. The model combines a non-linear analytical model for the morphodynamic evolution of the channel bed, a quasi-1D model to account for flow unsteadiness, and an ecological model describing riparian vegetation dynamics. Simplified closures are included to estimate the feedbacks among vegetation, hydrodynamics and sediment transport, which affect the morphology of the river-floodplain system. Model tests reveal the fundamental role of riparian plants in generating bio-morphological patterns at the advancing floodplain margin. Importantly, they provide insight into the biophysical controls of the 'bar push' mechanism and into its role in the lateral migration of meander bends and in the temporal variations of the active channel width.

  18. Morphodynamic length scale and long term river meandering dynamics

    NASA Astrophysics Data System (ADS)

    Lanzoni, S.; Frascati, A.

    2009-12-01

    The fully nonlinear simulation of the lateral migration of meandering channels, combined with an analytical description of the linearized flow field, gives a powerful and yet computationally accessible tool to investigate short and long term evolution of alluvial rivers. In the present contribution we focus on the long term behavior of meandering rivers. This class of dynamical systems is driven by the coexistence of various intrinsically nonlinear mechanisms which determine the possible occurrence of two different morphodynamic regimes: the sub-resonant and the super-resonant regime. Investigating the full range of morphodynamic conditions, we end up with a new morphodynamic length scale associated with spatially oscillating disturbances, accounting for both curvature-forced variations in velocity and depth and alternate bars. Once normalized with this length scale, the relevant morphologic features of the simulated long term patterns (i.e. the probability density function of the local channel curvature and the geometric characteristics of the oxbow lakes) tend to collapse on two distinct behaviors, depending on the dominant morphologic regime. The long term river meandering dynamics is then investigated. The occurrence of cutoff events is a key mechanism in the dynamics of these systems. They introduce a strong source of nonlinearity in the evolution of river meandering, which strongly contributes to the formation of the complex planform patterns usually observed in nature. To detect the possible signatures of a chaotic behavior or a self-organized criticality state triggered in river meandering dynamics by the repeated occurrence of cutoffs, some robust nonlinear methodologies have been applied to both the spatial series of local curvatures and the time series of long term channel sinuosity. The temporal distribution of cutoff inter-arrivals is also investigated. The results are consistent and show that, at least from a modelling point of view, no evidence of

  19. Analysis of Meander Migration Rates in Tidal Landscapes

    NASA Astrophysics Data System (ADS)

    Finotello, Alvise; D'Alpaos, Andrea; Ghinassi, Massimiliano; Lanzoni, Stefano; Marani, Marco; Rinaldo, Andrea

    2015-04-01

    Meandering patterns are universal features of tidal landscapes, which exert a great influence on the dynamics of tidal channel networks and on the stratigraphy of intertidal platforms. Despite their importance in landscape evolution and their ubiquity, tidal meanders have received less attention when compared to their fluvial counterparts. Quite a few studies, in fact, have focused on the morphodynamic evolution of tidal meanders, together with their planimetric shape and morphometric characteristics. To improve current understanding of tidal meander migration, a key step to address tidal meander evolution, we have analyzed a sequence of aerial photographs (from 1938 to present day) for about 400 meander bends, over 40 salt-marsh channels in the Northern part of the Venice Lagoon (Italy). Tidal meanders display similarities with fluvial meanders, although important differences emerge. Meanders cutting through the San Felice marsh follow the relationship between cartesian length and channel width, typical of meanders developed within different landscapes. However, meander migration rates, which were determined on the basis of three different methods, proved to be smaller than those characterizing fluvial meanders. Our analysis suggests mean migration rates of about 0.10 m/year, which is consistent with migration rates determined by previous studies on tidal meanders. The relationship between erosion (migration) rate and bend radius (R), both made dimensionless with channel width (W), displays a bell-shaped envelope pattern, in analogy with fluvial meanders although with smaller migration rates. In the tidal case, in fact, the largest migration rate is about 0.10 channel widths per year, which is smaller than the largest migration rate (0.20 channel widths per year) characterizing fluvial meanders that we found in the literature. Interestingly, in the case of tidal meanders the peak of the bell-shaped curve corresponds to a R/W ratio between 4 and 5, whereas the same

  20. River meanders and channel size

    USGS Publications Warehouse

    Williams, G.P.

    1986-01-01

    This study uses an enlarged data set to (1) compare measured meander geometry to that predicted by the Langbein and Leopold (1966) theory, (2) examine the frequency distribution of the ratio radius of curvature/channel width, and (3) derive 40 empirical equations (31 of which are original) involving meander and channel size features. The data set, part of which comes from publications by other authors, consists of 194 sites from a large variety of physiographic environments in various countries. The Langbein-Leopold sine-generated-curve theory for predicting radius of curvature agrees very well with the field data (78 sites). The ratio radius of curvature/channel width has a modal value in the range of 2 to 3, in accordance with earlier work; about one third of the 79 values is less than 2.0. The 40 empirical relations, most of which include only two variables, involve channel cross-section dimensions (bankfull area, width, and mean depth) and meander features (wavelength, bend length, radius of curvature, and belt width). These relations have very high correlation coefficients, most being in the range of 0.95-0.99. Although channel width traditionally has served as a scale indicator, bankfull cross-sectional area and mean depth also can be used for this purpose. ?? 1986.

  1. Migration Rate Of Tidal Meanders: Inferences From The Venice Lagoon

    NASA Astrophysics Data System (ADS)

    Finotello, A.; D'Alpaos, A.; Ghinassi, M.; Lanzoni, S.; Marani, M.; Rinaldo, A.

    2015-12-01

    Meandering channels are ubiquitous features of tidal landscapes. However, despite their fundamental role on the eco-morphodynamic evolution of these landscapes, tidal meanders have received less attention when compared to their fluvial counterparts. Improving current understanding of tidal meander migration, a largely-examined topic in fluvial landscapes, is a key step to highlight analogies and differences between tidal and fluvial cases. The migration of about 400 meander bends, belonging to 40 salt-marsh channels in the Northern Venice Lagoon (Italy), from 1968 to nowadays, has been investigated by means of both a classical method in fluvial frameworks and new procedure. Similarities with fluvial meanders occur, although important difference also emerge. Meanders cutting through the San Felice marsh follow the relationship between cartesian length and channel width, typical of meanders developed within different settings. However, meander migration rates proved to be smaller than those characterizing fluvial meanders. Indeed, the analysis of meander migration suggests a mean migration rate of about 0.10 m/year, consistent with the few data available in the literature. As for the fluvial case, the maximum-potential migration rate (i.e. the envelope curve of the relationship between migration rate and bend radius, both divided by channel width) reaches a maximum for radius-over-width ratio included between 2 and 3, regardless of the considered method. Nevertheless, the new-proposed method allows us to provide a more objective and continuous characterization. By using this new procedure, the channel curvature has finally been Fourier-analyzed, confirming the importance of even harmonics along the curvature spectrum. A correlation between migration rates and dominant harmonics seems to drive the evolution of tidal meanders and might represent a key-feature to distinguish them from their fluvial counterparts.

  2. River meander modeling and confronting uncertainty.

    SciTech Connect

    Posner, Ari J.

    2011-05-01

    This study examines the meandering phenomenon as it occurs in media throughout terrestrial, glacial, atmospheric, and aquatic environments. Analysis of the minimum energy principle, along with theories of Coriolis forces (and random walks to explain the meandering phenomenon) found that these theories apply at different temporal and spatial scales. Coriolis forces might induce topological changes resulting in meandering planforms. The minimum energy principle might explain how these forces combine to limit the sinuosity to depth and width ratios that are common throughout various media. The study then compares the first order analytical solutions for flow field by Ikeda, et al. (1981) and Johannesson and Parker (1989b). Ikeda's et al. linear bank erosion model was implemented to predict the rate of bank erosion in which the bank erosion coefficient is treated as a stochastic variable that varies with physical properties of the bank (e.g., cohesiveness, stratigraphy, or vegetation density). The developed model was used to predict the evolution of meandering planforms. Then, the modeling results were analyzed and compared to the observed data. Since the migration of a meandering channel consists of downstream translation, lateral expansion, and downstream or upstream rotations several measures are formulated in order to determine which of the resulting planforms is closest to the experimental measured one. Results from the deterministic model highly depend on the calibrated erosion coefficient. Since field measurements are always limited, the stochastic model yielded more realistic predictions of meandering planform evolutions. Due to the random nature of bank erosion coefficient, the meandering planform evolution is a stochastic process that can only be accurately predicted by a stochastic model.

  3. Meander migration modeling accounting for the effect of riparian vegetation

    NASA Astrophysics Data System (ADS)

    Eke, E.; Parker, G.

    2010-12-01

    A numerical model is proposed to study the development of meandering rivers so as to reproduce patterns of both migration and spatial/temporal width variation pattern observed in nature. The model comprises of: a) a depth-averaged channel hydrodynamic/morphodynamic model developed using a two-parameter perturbation expansion technique that considers perturbations induced by curvature and spatial channel width variation and b) a bank migration model which separately considers bank erosional and depositional processes. Unlike most previous meandering river models where channel migration is characterized only in terms of bank erosion, channel dynamics are here defined at channel banks which are allowed to migrate independently via deposition/erosion based on the local flow field and bank characteristics. A bank erodes (deposits) if the near bank Shields stress computed from the flow field is greater (less) than a specified threshold. This threshold Shields number is equivalent to the formative Shields stress characterizing bankfull flow. Excessive bank erosion is controlled by means of natural armoring provided by cohesive/rooted slump blocks produced when a stream erodes into the lower non-cohesive part of a composite bank. Bank deposition is largely due to sediment trapping by vegetation; resultant channel narrowing is related to both a natural rate of vegetal encroachment and flow characteristics. This new model allows the channel freedom to vary in width both spatially and in time as it migrates, so accounting for the bi-directional coupling between vegetation and flow dynamics and reproducing more realistic planform geometries. Preliminary results based on the model are presented.

  4. Numerical investigation of long-term planform dynamics and stability of river meandering on fluvial floodplains

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Bai, Yuchuan; Ma, Jianmin; Tan, Yan

    2011-09-01

    A mathematical model for river meandering and floodplain development is presented under the assumption of constant channel width, which combined Johanneson and Parker (1989) linear theory for flows in river bends and a conceptual depositional model from Howard (1992). A new bank erosion model is also developed, which takes into consideration of the nonlinearity in near-bank velocity and the outer bank height. Simulations reproduce the long-term behavior of river meandering and floodplain evolution in a way very similar to their natural processes. Based on the simulation results, stability of river meandering dynamics is discussed and the concept of filtration effect is introduced to highlight meandering rivers' capability to filter out arbitrarily applied planform disturbance. Simulations are also carried out to investigate the influence of the velocity nonlinearity and the outer bank height in bank erosion model, as well as their combinations. Results show that the consideration of velocity nonlinearity in bank erosion model leads to highly upstream-skewing geometry of fully developed river meanders, as well as a slower downstream migration of meander trains. The influence of nonlinearity in bank erosion model is much smaller than the influence of bank height, which reduces the bank migration rate exponentially in the newly introduced bank erosion model. The outer bank height consideration tends to decelerate the downstream migration rate of river meanders and accelerate lateral expansion of the floodplain as well. Consequently, a broader floodplain is generated compared with simulations without bank height considerations.

  5. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers.

    PubMed

    Braudrick, Christian A; Dietrich, William E; Leverich, Glen T; Sklar, Leonard S

    2009-10-01

    Meandering rivers are common on Earth and other planetary surfaces, yet the conditions necessary to maintain meandering channels are unclear. As a consequence, self-maintaining meandering channels with cutoffs have not been reproduced in the laboratory. Such experimental channels are needed to explore mechanisms controlling migration rate, sinuosity, floodplain formation, and planform morphodynamics and to test theories for wavelength and bend propagation. Here we report an experiment in which meandering with near-constant width was maintained during repeated cutoff and regeneration of meander bends. We found that elevated bank strength (provided by alfalfa sprouts) relative to the cohesionless bed material and the blocking of troughs (chutes) in the lee of point bars via suspended sediment deposition were the necessary ingredients to successful meandering. Varying flood discharge was not necessary. Scaling analysis shows that the experimental meander migration was fast compared to most natural channels. This high migration rate caused nearly all of the bedload sediment to exchange laterally, such that bar growth was primarily dependent on bank sediment supplied from upstream lateral migration. The high migration rate may have contributed to the relatively low sinuosity of 1.19, and this suggests that to obtain much higher sinuosity experiments at this scale may have to be conducted for several years. Although patience is required to evolve them, these experimental channels offer the opportunity to explore several fundamental issues about river morphodynamics. Our results also suggest that sand supply may be an essential control in restoring self-maintaining, actively shifting gravel-bedded meanders.

  6. Monte Carlo Simulation of River Meander Modelling

    NASA Astrophysics Data System (ADS)

    Posner, A. J.; Duan, J. G.

    2010-12-01

    This study first compares the first order analytical solutions for flow field by Ikeda et. al. (1981) and Johanesson and Parker (1989b). Ikeda et. al.’s (1981) linear bank erosion model was implemented to predict the rate of bank erosion in which the bank erosion coefficient is treated as a stochastic variable that varies with physical properties of the bank (e.g. cohesiveness, stratigraphy, vegetation density). The developed model was used to predict the evolution of meandering planforms. Then, the modeling results were analyzed and compared to the observed data. Since the migration of meandering channel consists of downstream translation, lateral expansion, and downstream or upstream rotations. Several measures are formulated in order to determine which of the resulting planform is closest to the experimental measured one. Results from the deterministic model highly depend on the calibrated erosion coefficient. Since field measurements are always limited, the stochastic model yielded more realistic predictions of meandering planform evolutions. Due to the random nature of bank erosion coefficient, the meandering planform evolution is a stochastic process that can only be accurately predicted by a stochastic model. Quasi-2D Ikeda (1989) flow solution with Monte Carlo Simulation of Bank Erosion Coefficient.

  7. RVR meander - a toolbox for river meander planform design and evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoring the meandering planform or spatial variability of historically meandering streams that have been channelized or highly disturbed is one of the most difficult aspects in river restoration. River planform and cross-sectional geometry are the result of complex interactions between flow, boun...

  8. Experimental investigation of Mars meandering rivers: Chemical precipitation process

    NASA Astrophysics Data System (ADS)

    Kim, W.; Lim, Y.; Cleveland, J.; Reid, E.; Jew, C.

    2014-12-01

    On Earth, meandering streams occur where the banks are resistant to erosion, which enhances narrow and deep channels. Often this is because the stream banks are held firm by vegetation. The ancient, highly sinuous channels with cutoffs found on Mars are enigmatic because vegetation played no role in providing bank cohesion and enhancing fine sediment deposition. Possible causes of the meandering therefore include ice under permafrost conditions and chemical processes. We conducted carbonate flume experiments to investigate possible mechanisms creating meandering channels other than vegetation. The experiment includes a tank that dissolves limestone by adding CO2 gas and produces artificial spring water, peristaltic pumps to drive water through the system, a heater to control the temperature of the spring water, and a flume where carbonate sediment deposits. Spring water containing dissolved calcium and carbonate ions moves through a heater to increase temperature, and then into the flume. The flume surface is open to the air to allow CO2 degassing, decrease temperature, and increase pH, which promotes carbonate precipitation. A preliminary experiment was done and successfully created a meander pattern that evolved over a 3-day experiment. The experiment showed lateral migration of the bend and avulsion of the stream, similar to a natural meander. The lateral variation in flow speed increased the local residence time of water, thus increasing the degassing of CO2 on the two sides of the flow and promoting more precipitation. This enhanced precipitation on the sides provided a mechanism to build levees along the channel and created a stream confined in a narrow path. This mechanism also potentially applies to Earthly single thread and/or meandering rivers developed and recorded before vegetation appeared on Earth's surface.

  9. Tidal Meander Migration: a Case Study from the Venice Lagoon

    NASA Astrophysics Data System (ADS)

    D'Alpaos, A.; Ghinassi, M.; Bellucci, L. G.; Marani, M.

    2014-12-01

    Meandering patterns are universal features of tidal landscapes which exert a great influence on the dynamics of tidal channel networks and on the stratigraphy of intertidal platforms. Despite their importance in landscape evolution and their ubiquity, tidal meanders have received less attention when compared to their fluvial counterparts. Quite a few studies, in fact, have focused on the morphodynamic evolution of tidal meanders, together with their planimetric shape and morphometric characteristics. To improve current understanding of tidal meander migration and its possible stratigraphic implications, we have analyzed a sequence of aerial photographs (from 1938 to present day) for a 20 m in diameter, abandoned tidal meander in the Venice Lagoon, and have carried out high-resolution sedimentological and chronostratigraphical analyses of channel deposits. Aerial photographs before and after the cutoff event have been used to infer a minimum velocity of migration. Well-cores have also been collected along a transect crossing through the neck zone in order to evaluate changes in grain size, sedimentation rates across the cutoff event, and gain further insight into the velocity of migration of meander bends. Spatial distribution of sedimentary facies (pointbar sand, oxbowlake and saltmarsh mud), grain size analyses, and 210 Pb and 137Cs chronometers highlighted that meander cutoff occurred progressively around 60 years ago with a velocity of migration of about 0.5m/year. The effectiveness of the methods and the high spatial and temporal resolution of the data call for further investigations and analyses of the type proposed herein, furthermore highlighting the potentiality of the study area as modern analogue for ancient tidal deposits.

  10. River Channel Patterns: Braided, Meandering, and Straight

    USGS Publications Warehouse

    Leopold, Luna B.; Wolman, M. Gordon

    1957-01-01

    Channel pattern is used to describe the plan view of a reach of river as seen from an airplane, and includes meandering, braiding, or relatively straight channels. Natural channels characteristically exhibit alternating pools or deep reaches and riffles or shallow reaches, regardless of the type of pattern. The length of the pool or distance between riffles in a straight channel equals the straight line distance between successive points of inflection in the wave pattern of a meandering river of the same width. The points of inflection are also shallow points and correspond to riffles in the straight channel. This distance, which is half the wavelength of the meander, varies approximately as a linear function of channel width. In the data we analysed the meander wavelength, or twice the distance between successive riffles, is from 7 to 12 times the channel width. It is concluded that the mechanics which may lead to meandering operate in straight channels. River braiding is characterized by channel division around alluvial islands. The growth of an island begins as the deposition of a central bar which results from sorting and deposition of the coarser fractions of the load which locally cannot be transported. The bar grows downstream and in height by continued deposition on its surface, forcing the water into the flanking channels, which, to carry the flow, deepen and cut laterally into the original banks. Such deepening locally lowers the water surface and the central bar emerges as an island which becomes stabilized by vegetation. Braiding was observed in a small river in a laboratory. Measurements of the adjustments of velocity, depth, width, and slope associated with island development lead to the conclusion that braiding is one of the many patterns which can maintain quasi-equilibrium among discharge, load, and transporting ability. Braiding does not necessarily indicate an excess of total load. Channel cross section and pattern are ultimately controlled by

  11. Meandering down to the Sea: The Wandering Ways of Rivers.

    ERIC Educational Resources Information Center

    Aslamazov, Lev

    1992-01-01

    Discusses the hydrodynamic reasons why a riverbed meanders through a plain. Describes how water movement at a bend in a river causes erosion and changes in the riverbed. Provides a mathematical model to explain the periodic shape of meanders of a river in a plain. (MDH)

  12. Model tracks sediment dynamics for highly curved meandering rivers

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-07-01

    Understanding the dynamics of meandering rivers—the twisting, turning, and wandering of waterways over time—is of concern to water managers and civil engineers. How curved a river is affects how it moves, and Ottevanger et al. built on existing models to improve representations of meandering dynamics for highly curved rivers.

  13. Nonlocal effects of local cutoff disturbances along the meandering Ucayali River in Peru

    NASA Astrophysics Data System (ADS)

    Schwenk, J.; Foufoula-Georgiou, E.

    2015-12-01

    For most migrating rivers, the time scale from bend initiation to cutoff is much greater than the period of recorded observations from aerial photography, historic maps, or field surveys. Efforts to elucidate meandering channel dynamics from such records have been further stymied by the poor time and spatial resolutions of the available data. The highly-active Ucayali River in Peru provides a unique opportunity to reveal natural, well-resolved meandering channel dynamics. In the past three decades alone, the Ucayali River has undergone many cutoffs including some bends growing from inception (nearly straight sections of river) until cutoff. Annual binarized water masks of the Ucayali River were generated from over 30 years of Landsat imagery. A nearly-automated methodology employing image-processing techniques computes pixel-resolution banklines, centerline, width, curvature, and migration rate along hundreds of kilometers of river. This methodology together with the rapid migration of the Ucayali River captures the effects of flow, bar size, tributaries, and cutoffs on local migration rates. In this study, we document how cutoff-generated local perturbations in slope and sediment storage induces nonlocal accelerated meander migration both upstream and downstream. This process introduces a feedback through which amplified migration rates increase cutoff rates while cutoffs amplify migration rates. We also relate the magnitude of cutoff reaches to the spatial and temporal extents of their corresponding accelerated migration rates.

  14. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers

    PubMed Central

    Braudrick, Christian A.; Dietrich, William E.; Leverich, Glen T.; Sklar, Leonard S.

    2009-01-01

    Meandering rivers are common on Earth and other planetary surfaces, yet the conditions necessary to maintain meandering channels are unclear. As a consequence, self-maintaining meandering channels with cutoffs have not been reproduced in the laboratory. Such experimental channels are needed to explore mechanisms controlling migration rate, sinuosity, floodplain formation, and planform morphodynamics and to test theories for wavelength and bend propagation. Here we report an experiment in which meandering with near-constant width was maintained during repeated cutoff and regeneration of meander bends. We found that elevated bank strength (provided by alfalfa sprouts) relative to the cohesionless bed material and the blocking of troughs (chutes) in the lee of point bars via suspended sediment deposition were the necessary ingredients to successful meandering. Varying flood discharge was not necessary. Scaling analysis shows that the experimental meander migration was fast compared to most natural channels. This high migration rate caused nearly all of the bedload sediment to exchange laterally, such that bar growth was primarily dependent on bank sediment supplied from upstream lateral migration. The high migration rate may have contributed to the relatively low sinuosity of 1.19, and this suggests that to obtain much higher sinuosity experiments at this scale may have to be conducted for several years. Although patience is required to evolve them, these experimental channels offer the opportunity to explore several fundamental issues about river morphodynamics. Our results also suggest that sand supply may be an essential control in restoring self-maintaining, actively shifting gravel-bedded meanders. PMID:19805077

  15. Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers.

    PubMed

    Braudrick, Christian A; Dietrich, William E; Leverich, Glen T; Sklar, Leonard S

    2009-10-01

    Meandering rivers are common on Earth and other planetary surfaces, yet the conditions necessary to maintain meandering channels are unclear. As a consequence, self-maintaining meandering channels with cutoffs have not been reproduced in the laboratory. Such experimental channels are needed to explore mechanisms controlling migration rate, sinuosity, floodplain formation, and planform morphodynamics and to test theories for wavelength and bend propagation. Here we report an experiment in which meandering with near-constant width was maintained during repeated cutoff and regeneration of meander bends. We found that elevated bank strength (provided by alfalfa sprouts) relative to the cohesionless bed material and the blocking of troughs (chutes) in the lee of point bars via suspended sediment deposition were the necessary ingredients to successful meandering. Varying flood discharge was not necessary. Scaling analysis shows that the experimental meander migration was fast compared to most natural channels. This high migration rate caused nearly all of the bedload sediment to exchange laterally, such that bar growth was primarily dependent on bank sediment supplied from upstream lateral migration. The high migration rate may have contributed to the relatively low sinuosity of 1.19, and this suggests that to obtain much higher sinuosity experiments at this scale may have to be conducted for several years. Although patience is required to evolve them, these experimental channels offer the opportunity to explore several fundamental issues about river morphodynamics. Our results also suggest that sand supply may be an essential control in restoring self-maintaining, actively shifting gravel-bedded meanders. PMID:19805077

  16. Sedimentology and facies of a Mississippi River meander belt

    SciTech Connect

    Pryor, W.A.; Jordan, D.W.

    1988-01-01

    The meander belt of the Mississippi River in Southeastern Missouri, consists of four facies: river channel, chute, levee, and abandoned channel fill. A depositional model and vertical sequences have been developed from drill cores, vibracores, fathometer surveys, and mapping of these facies. This model and the vertical sequences compare very well to ancient sequences. The vertical sequences observed in cores through the various facies systems have systematic variations and associations that serve as models for meander belt fluvial systems.

  17. Evolution of cutoffs across meander necks in Powder River, Montana, USA

    USGS Publications Warehouse

    Gay, G.R.; Gay, H.H.; Gay, W.H.; Martinson, H.A.; Meade, R.H.; Moody, J.A.

    1998-01-01

    Over a period of several decades, gullies have been observed in various stages of forming, growing and completing the cutoff of meander necks in Powder River. During one episode of overbank flow, water flowing over the down-stream bank of the neck forms a headctu. The headcut migrates up-valley, forming a gully in its wake, until it has traversed the entire neck, cutting off the meander. The river then follows the course of the gully, which is subsequently enlarged as the river develops its new channel. The complete process usually requires several episodes of high water: in only one of the five cases described herein was a meander cutoff initiated and completed during a single large flood.

  18. An integrated approach to investigate the reach-averaged bend scale dynamics of large meandering rivers

    NASA Astrophysics Data System (ADS)

    Monegaglia, Federico; Henshaw, Alex; Zolezzi, Guido; Tubino, Marco

    2016-04-01

    Planform development of evolving meander bends is a beautiful and complex dynamic phenomenon, controlled by the interplay among hydrodynamics, sediments and floodplain characteristics. In the past decades, morphodynamic models of river meandering have provided a thorough understanding of the unit physical processes interacting at the reach scale during meander planform evolution. On the other hand, recent years have seen advances in satellite geosciences able to provide data with increasing resolution and earth coverage, which are becoming an important tool for studying and managing river systems. Analysis of the planform development of meandering rivers through Landsat satellite imagery have been provided in very recent works. Methodologies for the objective and automatic extraction of key river development metrics from multi-temporal satellite images have been proposed though often limited to the extraction of channel centerlines, and not always able to yield quantitative data on channel width, migration rates and bed morphology. Overcoming such gap would make a major step forward to integrate morphodynamic theories, models and real-world data for an increased understanding of meandering river dynamics. In order to fulfill such gaps, a novel automatic procedure for extracting and analyzing the topography and planform dynamics of meandering rivers through time from satellite images is implemented. A robust algorithm able to compute channel centerline in complex contexts such as the presence of channel bifurcations and anabranching structures is used. As a case study, the procedure is applied to the Landsat database for a reach of the well-known case of Rio Beni, a large, suspended load dominated, tropical meandering river flowing through the Bolivian Amazon Basin. The reach-averaged evolution of single bends along Rio Beni over a 30 years period is analyzed, in terms of bend amplification rates computed according to the local centerline migration rate. A

  19. Extreme sediment pulses generated by bend cutoffs along a large meandering river

    NASA Astrophysics Data System (ADS)

    Zinger, Jessica A.; Rhoads, Bruce L.; Best, James L.

    2011-10-01

    In meandering rivers, bend cutoffs have long been recognized as an important mechanism of change in the path of the channel. Meander bend cutoffs can develop by the progressive migration of an elongated bend onto itself, which forms a neck cutoff, or by the erosion of a new channel across the neck of the bend, which is known as a chute cutoff. River cutoffs affect channel navigation, and form meander scars and oxbow lakes in river floodplains, which are important habitats for riparian ecosystems. The importance of cutoff processes in meander dynamics is well established, but the effects of cutoffs on overall sediment flux are poorly characterized. Here we use aerial imagery, global positioning system mapping and measurements of channel bathymetry to estimate the amount of sediment released by two chute cutoffs on the Wabash River in the Midwestern USA. We find that each event triggered the rapid delivery of sediment into the river, at rates that are one to five orders of magnitude larger than those produced by lateral migration of individual bends. We find that much of this material was deposited immediately downstream, at the confluence of the Wabash and Ohio rivers, which led to significant changes in channel morphology. This sedimentation ultimately impeded barge traffic and necessitated extensive dredging.

  20. Rivers meandering in bedrock: Lithologic, climatic, and process controls on form and evolution

    NASA Astrophysics Data System (ADS)

    Zunka, J. P.; Lancaster, S. T.

    2014-12-01

    Whereas meander wavelengths of alluvial rivers characteristically scale with bankfull discharge, bedrock meander wavelengths are typically 5-10 times greater than the scaling relationship for alluvial rivers would suggest, a fact that has led some to conclude that bedrock meanders are "underfit." Others, however, have reasoned that larger dominant discharges should be expected for bedrock meanders to erode bank toes and mobilize sediment in bank-shielding scree piles, which often accompany steep, even vertical, outside banks capable of supplying coarse debris via landslide, debris flow, and rockfall. We attempt to test this hypothesis by finding dominant discharges for the Buffalo National River, Arkansas, by several methods. First, assuming that, as with alluvial meanders, bedrock meander wavelengths are 7-15 times hydraulic width at dominant discharge, we use cross-sections extracted from LiDAR-derived DEMs to find discharges corresponding to objectively-determined meander wavelengths. Second, assuming that dominant discharge must mobilize scree mantling outer-bank toe slopes, we use measured grain size distributions and cross sections to determine this discharge. For each of these calculated discharges, we use flow-duration curves to find corresponding recurrence intervals. Third, assuming that mean residence times of scree are similar to dominant discharge recurrence intervals, we use measured scree volumes and flux rates inferred from lateral migration rates to find those residence times. Preliminary results for the site with the longest gauge record yield a mean recurrence interval of 26 yrs corresponding to a meander wavelength-to-width scaling ratio of 11 (9-139 yrs for scaling ratios of 7-15). Recurrence intervals found by the other methods await field and cosmogenic isotope concentration measurements.

  1. River meandering on Earth and Mars: A comparative study of Aeolis Dorsa meanders, Mars and possible terrestrial analogs of the Usuktuk River, AK, and the Quinn River, NV

    NASA Astrophysics Data System (ADS)

    Matsubara, Yo; Howard, Alan D.; Burr, Devon M.; Williams, Rebecca M. E.; Dietrich, William E.; Moore, Jeffery M.

    2015-07-01

    The paleo-meanders in the Aeolis Dorsa (AD) region show that meandering channels can develop in the absence of vegetation. Three possible mechanisms other than vegetation could contribute to the bank cohesion required to promote meandering: permafrost, abundant mud, and chemical cementation. Banks at the meandering Quinn River show little vegetation cover. Almost all sediment samples collected from the Quinn River deposits contain at least 41% mud (silt/clay), which is much higher than for most meandering streams. Ion chromatography (IC) analysis and scanning electron microscope (SEM) images showed presence of salts in river waters and sediments which may induce fine sediment to flocculate and be deposited. We find that bank cohesion promoting meandering can be provided by silt/clay, the deposition of which may be induced by dissolved salts. The sinuous Usuktuk River in the continuous permafrost region near Barrow, Alaska exhibited no exposed permafrost on stream banks. Instead vegetation seemed to be the dominant control of bank erosion. We have not found evidence for ice control of bank cohesion in this or other terrestrial rivers of similar size and in meandering pattern to the Martian AD meanders. We conclude that bank cohesion in the AD meanders was probably provided by deposition of fine suspended sediment that was flocculated by dissolved salts.

  2. Flow Structure and Channel Change in a Chute Cutoff along a Large Meandering River

    NASA Astrophysics Data System (ADS)

    Rhoads, B. L.; Best, J.; Johnson, K.; Engel, F. L.

    2009-12-01

    Meander cutoffs, which develop when flow cuts across the narrow neck of a bend, are common features along actively migrating meandering rivers. Despite the importance of cutoffs in the dynamics of river meandering and floodplain sedimentation, few, if any, studies have documented in detail the fluvial processes involved in the development of a meander cutoff. This paper examines the morphodynamics of a chute cutoff along the Wabash River, Illinois-Indiana, immediately following initiation of the cutoff. The original cutoff channel formed across the neck of Mackey Bend, a meander loop immediately upstream of the confluence with the Ohio River, during a major flood in June 2008. The formation of the cutoff channel likely involved migration of a headcut from the downstream side to the upstream side of the meander neck along the path of a floodplain slough. A key focus of the investigation has been to document flow structure at the upstream and downstream ends of the cutoff channel so that patterns of flow can be related to morphological change. Three separate measurement campaigns using an acoustic doppler current profiler (ADCP) and single-beam echosounder were conducted between January and May 2009 to determine 3D flow structure and bed morphology during events with different discharges and flow stages. In addition, channel dimensions were surveyed using a dGPS system in September 2008 and in August 2009. Results indicate that the cutoff channel has widened dramatically over a one-year period, increasing its width by as much as 100 percent. Curvature of flow into the entrance of the cutoff channel from the Wabash River generates strong helical motion that advects momentum toward the outer bank, resulting in high velocities near the bank toe and ongoing bank retreat through slab failures. This flow pattern, accentuated by dramatic widening of the cutoff channel, has resulted in deposition along the inner bank and development of a large bar platform at this location

  3. Detailed river stage mapping and head gradient analysis during meander cutoff in a laboratory river

    NASA Astrophysics Data System (ADS)

    Han, Bangshuai; Endreny, Theodore A.

    2014-02-01

    Analytical models of river evolution predict meander narrowing and elongation which creates sinuosity-driven hyporheic exchange across the meander neck, by decreasing flow distance and increasing head loss. We used a laboratory river table and close range photogrammetry to map and analyze sinuosity as a driver of head gradients and hyporheic exchange during cutoff. The river valley had relatively high slopes (1.8%) and moderately cohesive sediment (10% talc, 90% sand) to facilitate cutoff, and ratios of horizontal to vertical scaling were distorted to achieve dynamic similitude (Re = 3200). Incipient to cutoff, the head gradient across the neck increased due to a narrowing neck, upstream aggradation, and downstream degradation. Longitudinal and transverse river surface slopes around the meander bend increased as the meander approached cutoff. The steep head gradient across the moderately cohesive meander neck generated seepage erosion and scour that formed a low-sinuosity avulsion. Sediment-rich flow in the avulsed channel aggraded the downstream bed and separated the active channel and oxbow lake. The limitation in geometric and dynamic similitude in the river table limits extrapolation to natural rivers, yet river evolution may involve aggradation and degradation induced channel head loss and turnover hyporheic exchange as well as seepage-induced meander neck erosion. Our submillimeter maps of meander morphology and water stage provide data to parameterize river evolution and hyporheic exchange models, and may inform analysis and mapping of field sites.

  4. Rapid replacement of riparian rainforest habitat and the impacts on the meandering dynamics of the Kinabatangan River, Borneo

    NASA Astrophysics Data System (ADS)

    Horton, Alexander J.; Constantine, José A.

    2014-05-01

    Meandering rivers are defined by their nature to migrate, remobilising floodplain sediment and constructing new surfaces for riparian vegetation to colonise. The presence of riparian vegetation has long been known to limit the ability of rivers to erode riverbanks, but it has remained unclear the principal means by which vegetation provides this function. As a result, most models that predict meandering behaviour do not fully incorporate vegetation, thereby limiting their utility where forest is rapidly replaced. The problem is particularly acute along the Kinabatangan River of Sabah in Malaysian Borneo, where oil palm plantations are replacing one of the oldest riparian rainforests on the planet. The area of Sabah has seen rapid and extensive land use change in the last 40 years, as virgin rainforest has been systematically cleared for logging, and to make way for oil palm plantations. In the 18 years from 1990 to 2008, Sabah lost half of its intact rainforest, which equates to more than 1.85 million hectares. Using Landsat imagery dating back to 1973, we report here the impacts of this rapid land-use change on rates of meander migration on a 280-km reach of the Kinabatangan River. The river planform has been remarkably stable throughout the time period of study, but individual meanders show a rapid response to large discharge events, migrating over an order of magnitude faster than nearby reaches. Rapidly migrating meanders generally occur along portions of floodplain that have been artificially cleared of riparian vegetation, potentially resulting in significant increases in sediment load and within-channel bar development. A field campaign is planned to investigate the mechanisms by which riparian vegetation effect meander migration in these tropical regions.

  5. Simulating river meandering processes using stochastic bank erosion coefficient

    NASA Astrophysics Data System (ADS)

    Posner, Ari J.; Duan, Jennifer G.

    2012-08-01

    This study first compares the first order analytical solutions for flow field by Ikeda et. al. (1981) and Johanesson and Parker (1989b). Ikeda et. al.'s (1981) linear model of bank erosion was implemented to predict the rate of bank erosion in which the bank erosion coefficient is treated as a stochastic variable that varies with physical properties of the bank (e.g. cohesiveness, stratigraphy, vegetation density). The developed model was used to predict the evolution of meandering planforms. Then, the modeling results were analyzed and compared to the observed data. Because the migration of meandering channels consists of downstream translation, lateral expansion, and downstream or upstream rotations, several measures are formulated to determine which of the resulting planform is closest to the experimental measured one. Results from the deterministic model highly depend on the calibrated erosion coefficient. Because field measurements are always limited, the stochastic model yielded more realistic predictions of meandering planform evolutions. Because the coefficient of bank erosion is a random variable, the meandering planform evolution is a stochastic process that can only be accurately predicted by a stochastic model.

  6. Flow Structure and Channel Change in Chute Cutoffs On Meandering Rivers

    NASA Astrophysics Data System (ADS)

    Zinger, J. A.; Rhoads, B. L.; Best, J. L.; Johnson, K. K.

    2011-12-01

    Freely meandering rivers typically exhibit complex, continuously evolving patterns of planform geometry involving elongation of the channel path through lateral migration and shorting of this path through bend cutoffs. Despite the importance of cutoffs in shaping the planform geometry of meandering rivers, the fluvial processes operative immediately after initiation of a cutoff are poorly understood. Two recent chute cutoff events on a single bend on the Wabash River, IL-IN, have provided an unprecedented opportunity to document the morphologic evolution and flow structure of chute cutoffs in a large, unregulated, meandering river. Here, we present results of ADCP measurements of three-dimensional flow velocity and bed topography at these cutoffs and describe a conceptual model for the morphodynamics of chute cutoffs prior to oxbow lake formation. Our results indicate that the flow structure at upstream and downstream ends of cutoff channels, prior to plugging of the entrance and exit of the abandoned bend with sediment, is analogous to flow through diffluence - confluence units. The interaction of this flow structure with an erodible bed and banks can cause rapid widening of the upstream end of the cutoff channel and bar development i) in the main channel where velocities are reduced, and ii) in the separation zone of the cutoff channel. Over time, these patterns of deposition and erosion will lead formation of an oxbow lake and complete capture of the flow by the cutoff channel.

  7. Captures, Cutoffs, and Autogenic Drainage Basin Reorganization from Bedrock River Meandering in the Oregon Coast Range

    NASA Astrophysics Data System (ADS)

    Johnson, K. N.; Finnegan, N. J.

    2015-12-01

    Meandering bedrock channels in the Oregon Coast Range (OCR), USA, have lateral migration rates far in excess of vertical incision rates. Consequently, the sweeping of trunk streams through this landscape can locally exert a much stronger influence on tributary channel long profiles than far-field tectonic forcing of base-level. Here, we use LiDAR-data to explore the influence of lateral channel mobility on the evolution of tributaries to the Smith River, in the OCR. We focus on two processes that dramatically and instantaneously change tributary long profiles: 1) Capture of tributaries by growing meander bends, and 2) Meander bend neck cutoffs on the main-stem that leave tributaries disconnected from base-level lowering. We focus on these two types of events because they provide clear examples of autogenic drivers of landscape disequilibrium at the sub-watershed scale in a landscape that is commonly argued to reflect steady tectonic forcing of base-level. We show that tributary streams are significantly more likely to flow into the leading edge of meander bends, testifying to the repeated capture of tributaries by growing bends. Examples of eminent captures by migrating bends, and examples with large knick points along recently captured tributaries suggest that the autogenic capture of tributaries by growing bends is a fundamental cause of transience in tributary channels in this landscape. To demonstrate the influence of the process of meander bend neck cutoff on tributary long profile evolution, we compare the long profiles of 34 tributaries that were hung above the main-stem of the Smith River following neck cutoff events. These stagnated tributary channels typically exhibit large convexities that record ongoing lowering of the trunk stream. Measured heights of these hanging tributaries implies that the timescale of adjustment for tributaries following cutoff events is ~ 105-106 years. The timescale of adjustment of tributary channels following meander cutoff

  8. Channel changes and floodplain management in the meandering middle Ebro River, Spain

    NASA Astrophysics Data System (ADS)

    Ollero, Alfredo

    2010-05-01

    The 346 km of the middle Ebro River between Logroño and La Zaida is a free meandering channel in a wide floodplain. This reach contains a discontinuous riparian corridor, including valuable riparian forests and oxbow lakes. The Ebro has witnessed substantial changes in channel morphology, gravel bars, riparian vegetation and floodplain uses over the last 80 years. The growth in sinuosity, migrations and meander cut-offs have been frequent before 1981. Afterwards, bank protections and dykes have stabilized the channel. There has been a progressive and significant decrease of both the area covered by water and the gravel bars without plant colonization. As a result the width of the riparian corridor has been dramatically reduced for human use. The deceleration and near elimination of the free meander dynamics of the Ebro channel represent an important loss of natural heritage. Dams, land-use changes throughout the basin, and construction of flood defences that restrict the main channel have changed the river system behaviour, which urgently needs a management plan combining both improvement and risk reduction. The solution proposed is the creation of a "Fluvial Territory".

  9. a Linear Model for Meandering Rivers with Arbitrarily Varying Width

    NASA Astrophysics Data System (ADS)

    Frascati, A.; Lanzoni, S.

    2011-12-01

    Alluvial rivers usually exhibit quite complex planforms, characterized by a wide variety of alternating bends, that have attracted the interest of a large number of researchers. Much less attention has been paid to another striking feature observed in alluvial rivers, namely the relatively regular spatial variations attained by the channel width. Actively meandering channels, in fact, generally undergo spatial oscillations systematically correlated with channel curvature, with cross sections wider at bends than at crossings. Some other streams have been observed to exhibit irregular width variations. Conversely, rivers flowing in highly vegetated flood plains, i.e. canaliform rivers, may exhibit an opposite behavior, owing to the combined effects of bank erodibility and floodplain depositional processes which, in turn, are strictly linked to vegetation cover. Similarly to streamline curvatures induced by bends, the presence of along channel width variations may have remarkable effects on the flow field and sediment dynamics and, thereby, on the equilibrium river bed configuration. In particular, spatial distribution of channel curvature typically determines the formation of a rhythmic bar-pool pattern in the channel bed strictly associated with the development of river meanders. Channel width variations are on the contrary characterized by a sequence of narrowing, yielding a central scour, alternated to the downstream development of a widening associated with the formation of a central bar. Here we present a morphodynamic model that predict at a linear level the spatial distribution of the flow field and the equilibrium bed configuration of an alluvial river characterized by arbitrary along channel distributions of both the channel axis curvature and the channel width. The mathematical model is averaged over the depth and describes the steady, non-uniform flow and sediment transport in sinuous channels with a noncohesive bed. The governing two-dimensional equations

  10. Morphodynamic regime and long-term evolution of meandering rivers

    NASA Astrophysics Data System (ADS)

    Frascati, Alessandro; Lanzoni, Stefano

    2009-06-01

    In the present contribution we focus our attention on the long-term behavior of meandering rivers, a very common pattern in nature. This class of dynamical systems is driven by the coexistence of various intrinsically nonlinear mechanisms which determine the possible occurrence of two different morphodynamic regimes: the subresonant and the superresonant regimes. Investigating the full range of morphodynamic conditions, we objectively compare the morphologic characteristics exhibited by synthetically generated and observed planimetric patterns. The analysis is carried out examining, through principal component analysis, a suitable set of morphological variables. We show that even in the presence of the strong filtering action exerted by cutoff processes, a closer, although not yet complete, similarity with natural meandering planforms can be achieved only by adopting a flow field model which accounts for the full range of morphodynamic regimes. We also introduce a new morphodynamic length scale, ?m, associated with spatially oscillating disturbances. Once normalized with this length scale, the relevant morphologic features of the simulated long-term patterns (e.g., the probability density function of local curvature and the geometric characteristics of oxbow lakes) tend to collapse on two distinct behaviors, depending on the dominant morphologic regime.

  11. Channel dynamics and habitat development in a meandering, gravel bed river

    NASA Astrophysics Data System (ADS)

    Harrison, L. R.; Legleiter, C. J.; Wydzga, M. A.; Dunne, T.

    2011-04-01

    We investigated how channel morphology, flow complexity, and habitat characteristics in a meandering gravel bed river evolved over time from a simple, reconfigured initial condition. Using a time series of topographic data, we measured rates of channel migration and morphologic change, documented patterns of sediment storage, and estimated rates of sediment supply. We constructed, calibrated, and validated hydrodynamic models to quantify how the evolving morphology influenced hydraulic conditions, flow complexity, and habitat suitability for Chinook salmon spawning and rearing. For a series of meander bends with constant curvature, similar bank materials, and an identical flow history, sediment supply and bar storage directly influenced channel migration rates. Habitat modeling indicated that the availability of Chinook salmon spawning habitat increased over time, whereas the majority of the reach continues to provide only low- to medium-quality rearing habitat for juvenile salmonids, primarily because of a lack of low-velocity refuge zones. However, other metrics of flow complexity indicate that areas of favorable flow conditions gradually expanded as point bars developed along the inner bank of each bend. These results indicate that although sediment supply can stimulate channel change and diversify river morphology, which acts to promote flow complexity and provide spawning habitat, these sediment-driven morphological changes might not create bioenergetically favorable habitat for juvenile salmonids.

  12. Topographic Signatures of Meandering Rivers with Differences in Outer Bank Cohesion

    NASA Astrophysics Data System (ADS)

    Kelly, S. A.; Belmont, P.

    2014-12-01

    Within a given valley setting, interactions between river hydraulics, sediment, topography, and vegetation determine attributes of channel morphology, including planform, width and depth, slope, and bed and bank properties. These feedbacks also govern river behavior, including migration and avulsion. Bank cohesion, from the addition of fine sediment and/or vegetation has been recognized in flume experiments as a necessary component to create and maintain a meandering channel planform. Greater bank cohesion slows bank erosion, limiting the rate at which a river can adjust laterally and preventing so-called "runaway widening" to a braided state. Feedbacks of bank cohesion on channel hydraulics and sediment transport may thus produce distinct topographic signatures, or patterns in channel width, depth, and point bar transverse slope. We expect that in bends of greater outer bank cohesion the channel will be narrower, deeper, and bars will have greater transverse slopes. Only recently have we recognized that biotic processes may imprint distinct topographic signatures on the landscape. This study explores topographic signatures of three US rivers: the lower Minnesota River, near Mankato, MN, the Le Sueur River, south central MN, and the Fall River, Rocky Mountain National Park, CO. Each of these rivers has variability in outer bank cohesion, quantified based on geotechnical and vegetation properties, and in-channel topography, which was derived from rtkGPS and acoustic bathymetry surveys. We present methods for incorporating biophysical feedbacks into geomorphic transport laws so that models can better simulate the spatial patterns and variability of topographic signatures.

  13. Geomorphic and vegetation changes in a meandering dryland river regulated by a large dam, Sauce Grande River, Argentina

    NASA Astrophysics Data System (ADS)

    Casado, Ana; Peiry, Jean-Luc; Campo, Alicia M.

    2016-09-01

    This paper investigates post-dam geomorphic and vegetation changes in the Sauce Grande River, a meandering dryland river impounded by a large water-conservation dam. As the dam impounds a river section with scarce influence of tributaries, sources for fresh water and sediment downstream are limited. Changes were inspected based on (i) analysis of historical photographs/imagery spanning pre- (1961) and post-dam (1981, 2004) channel conditions for two river segments located above and below the dam, and (ii) field survey of present channel conditions for a set of eight reference reaches along the river segments. Whilst the unregulated river exhibited active lateral migration with consequent adjustments of the channel shape and size, the river section below the dam was characterized by (i) marked planform stability (93 to 97%), and by (ii) vegetation encroachment leading to alternating yet localized contraction of the channel width (up to 30%). The present river displays a moribund, stable channel where (i) redistribution of sediment along the river course no longer occurs and (ii) channel forms constitute a remnant of a fluvial environment created before closing the dam, under conditions of higher energy. In addition to providing new information on the complex geomorphic response of dryland rivers to impoundment, this paper represents the very first geomorphic assessment of the regulated Sauce Grande and therefore provides an important platform to underpin further research assessing the geomorphic state of this highly regulated dryland river.

  14. Measuring and modeling multidimensional dispersion in a meandering river

    NASA Astrophysics Data System (ADS)

    Logan, B. L.; Nelson, J. M.; Runkel, R. L.; McDonald, R. R.

    2009-04-01

    As part of a study to separate and characterize the active and passive components of sturgeon larval dispersal in a large river, we made detailed measurements of the dispersion of a large pulse of Rhodamine dye injected at a single upstream point. The study occurred on the Kootenai River, USA, a 200m-wide meandering river with an unusually low gradient, 2x10-5, and an average depth of 5 m at the moderate study flow of 271 m3/s. For the first 14 river kilometers downstream from the injection site, a detailed concentration data set describing the spatial and temporal evolution of the dye pulse was obtained using GPS receivers and high-accuracy fluorometers mounted on several boats. Beyond this initial reach, the dye was predominantly well-mixed in the cross-stream direction except near the leading and trailing edges of the pulse, and only longitudinal dispersion was measured. These measurements were made at a series of 11 fixed locations for an additional 45 river kilometers downstream, at which point peak dye concentrations were near the detection limit. Even for a relatively simple channel, the data indicate that local topography and bank irregularity exert a strong influence on the distribution of dye. While most of the dye pulse was apparently well mixed in the cross-stream and vertical directions, deep pools and lateral separation zones produced complex 3-dimensional structure in the concentration field, especially at the leading edge of the dye pulse. The dispersion data show that travel times in different reaches were more variable than predicted by a simple 1-dimensional model. Comparisons of the field data with results from multidimensional computational models indicate that uncommon channel features play a disproportionately important role in determining the storage and subsequent release of constituents that are passively advected and diffused.

  15. Changes in morphometric meander parameters identified on the Karoon River, Iran, using remote sensing data

    NASA Astrophysics Data System (ADS)

    Yousefi, Saleh; Pourghasemi, Hamid Reza; Hooke, Janet; Navratil, Oldrich; Kidová, Anna

    2016-10-01

    River meander dynamics and mobility are important indicators of environmental change related to climate changes and anthropogenic activities at local and river basin scales. The aim of the present study is to identify morphological changes of the Karoon River in Iran using high accuracy maps and Landsat satellite images by analyses during the time period 1989-2008. In this study, 20 meandering reaches were analyzed over a 128-km-long river reach located in the middle part of the Karoon River, Iran. Morphometric indicators such as: river width (W), meander neck length (L), axis length (A), radius of curvature (R), water flow length (S), and sinuosity of meander (C) were extracted for the identified meanders. The results of a paired t-test showed that river width (W) and meander neck length (L) have significantly changed during the study period (1989-2008), with an increase of + 3.5 m for W and a decrease of 274 m for L. Spearman correlation analysis has shown that meander parameter changes are highly correlated to each other. The parameters that do not have significant correlation together are C with W and L, W and L, and L with S and A. During the period of the study, the flow length and river sinuosity decreased for the whole river reach, by 4.77 km and 0.11, respectively. Analysis of land use/land cover categories (1989 and 2008) using the support vector machine (SVM) and kernel function method served as one of the tools for interpretation of the meander parameter changes. These changes can be attributed not only to LU/LC (riparian vegetation to agriculture area ratio) but also to dam construction in the upstream part of the river that leads to major hydrological regime and sediment transfer alteration. Sediment extraction may also be an important factor.

  16. HYDRODYNAMICS AND SEDIMENT TRANSPORT IN LOWER MISSISSIPPI RIVER MEANDER BENDS (LOUISIANA): IMPLICATIONS FOR LARGE SEDIMENT DIVERSIONS

    NASA Astrophysics Data System (ADS)

    Allison, M. A.; McCorquodale, A.; Meselhe, E. A.

    2009-12-01

    Field data collection and numerical modeling is being conducted in the lower Mississippi River in the region of a meander bend at Myrtle Grove, LA (river km 96 above Head of Passes) in support of a proposed large water and sediment diversion (1,130-2,830 cms) for coastal wetland restoration. Field studies in October 2008, April and May 2009, at discharges ranging from 11,000-21,000 cms, examined the role of bend dynamics on sediment transport through this reach relative to control sites further downriver and USGS monitoring stations upriver. Suspended loads and grain size character measured by ADCP (velocities and backscatter), isokinetic point sampler (P-63), and optical sensors (LISST, OBS, transmissometer) indicate that during the rising-to-high discharge phase, sand lifting off from the downstream edge of the lateral bar upriver of the bend augments that carried from further upriver, and is entrained in the upper 10-25m of the water column. This excess suspended sand is advected around the bend before concentrations are reduced to background levels over the lateral bar downstream of the bend. Bedload transport rates measured by repeat swath bathymetric mapping of migrating dunes are comparable upstream of the bend, downstream, and in the control sites. However, no bedforms are observed in the bend thalweg (up to 60 m deep) supporting the dominance of suspended sand transport in the bend. Both 1D (HEC-RAS and HEC6-T) and 3D (Flow3D) numerical hydrodynamic and sediment transport modeling is underway to simulate this process and the large-scale eddy present in the bend that generates upriver transport along the inside of the meander bend at all observed discharges. Our preliminary results suggest that the outside of meander bends might be an appropriate site for sediment diversions that draw near-surface water from this sediment-rich layer.

  17. STUDY ON PREVENTING DOWNSTREAM MOVEMENT OF BARS IN MEANDERING ROCK-BED RIVERS

    NASA Astrophysics Data System (ADS)

    Hayakawa, Hiroshi; Miyamoto, Hiroshi; Natsui, Kousei

    For preserving a comfortable river ecosystem, it is important to restore the riffle and pools within engineered channels, where should play a role in the habitat diversity. It will be no easy task to restore the pool-riffle and bars in flat rock-bed river which is lightly covered with gravels, as contrasted with in the gravel river. Kinoshita and Miwa (1974) proposed the condition for preventing downstream movement of bars in meandering gravel rivers. This work is intended to apply this condition to meandering rock-bed rivers. By depositing sand and gravel in meandering section, it will be assumed to generate some bars in spite of rock-bed rivers. We investigate the validity of the Kinoshita and Miwa’s condition by experimental and numerical survey in mobile-bed and fixed-bed channel. For mobile-bed, we reconfirmed that the Kinoshita and Miwa’s condition is valid. For rock-bed, we derive the condition of deposition of sand in meandering section by relating with the ratio of meander length to channel width and the angle of meander.

  18. Steady-state unsteadiness: drainage network reorganization triggered by bedrock river meandering in the Oregon Coast Range

    NASA Astrophysics Data System (ADS)

    Johnson, K. N.; Finnegan, N. J.

    2013-12-01

    In most landscapes, vertical incision of bedrock stream networks transmits base-level signals into the landscape interior, and is thus the primary control on landscape evolution. Some bedrock channels, however, also have the capacity to move laterally within a landscape via active bedrock meandering. This is common in diverse lithologies including many sedimentary rocks (e.g. California and Oregon Coast Ranges, Colorado Plateau) and basalt (e.g. Columbia River Flood Basalt, Hawaiian Islands). If active meandering of the main stem channel occurs, rates of base-level lowering at the mouth of tributary watersheds will fluctuate over time, even if the base-level lowering rate at the mouth of the main stem channel is constant over time. This is because lateral migration of the main stem channel causes elongation or truncation of the lower reaches of tributaries, which in turn changes slopes and thus tributary incision rates. In addition, as meander bends along the main stem channel grow, they can capture tributaries from other main stem reaches, causing sudden drainage network reorganization and impulsive base-level lowering. Thus a landscape with steady tectonic and climatic forcing may nevertheless experience significant unsteadiness because of the process of meandering itself. Here we test our conceptual model that active meandering of a main stem channel exerts a fundamental control on the relative base-level lowering of tributary watersheds throughout the landscape. To this end, we analyze high resolution LiDAR elevation data from the Smith River, in the Oregon Coast Range, argued to be a classic example of a 'steady state' landscape. We find that tributary junctions are concentrated on the outside of active meander bends, consistent with the hypothesis that actively growing meander bends 'collect' tributaries as they propagate into the landscape. In addition, we find that longitudinal profiles of these tributaries are not consistent with a 'steady state' condition

  19. Hydraulic interactions between a meandering river channel and its floodplain during an overbank flood

    NASA Astrophysics Data System (ADS)

    Harrison, L.; Dunne, T.; Fisher, B.

    2012-12-01

    River channel and floodplain complexity is generated by the lateral migration of meandering river channels across the floodplain surface. The main driver of meander migration is the flow field which erodes the outer bank of river bends, scours pools, creates topographic variability on the floodplain and interacts with riparian vegetation. Flows between channels and floodplains are generally thought to be highly three-dimensional due to the presence of secondary circulation cells and helical flow patterns observed in laboratory experiments, yet few field datasets exist to test or validate existing conceptual models. Flow over and through floodplain vegetation has also been difficult to characterize at the field scale. We took advantage of a remarkably long and stable 5-year flood discharge to measure flow fields across the floodplain and in curved reaches of the gravel-bed Merced River In California to document the hydraulic interactions between the channel and floodplain. We then developed, calibrated and validated a quasi-3D hydrodynamic model of the flows in order to expand the interpretation of the results. Due to the spatial variability in both topography and flow resistance, the modeling required detailed mapping of the channel-floodplain surface and vegetation with a terrestrial LiDAR scanner and RTK GPS units. The results highlight several general aspects of the channel-floodplain flow during an overbank flow event: (1) the flow field in the channel was largely two-dimensional with only weak helical flow patterns; (2) the highest channel velocities and boundary shear stresses occurred at the local maxima in bend curvature where lateral migration has been documented via repeat topographic surveys; (3) flow velocities rapidly decelerated as water was decanted from the channel onto the floodplain where the velocity magnitude was roughly 20-30% of the average channel velocity; (4) dense vegetation along the channel margins enhanced channel velocities but reduced

  20. Morphodynamics of neck cutoffs on elongate meander loops, White River, Arkansas, USA

    NASA Astrophysics Data System (ADS)

    Konsoer, K. M.

    2015-12-01

    Meander cutoff and oxbow lake formation are essential components of alluvial architecture and riverine habitat of meandering river floodplains. Yet, despite their ubiquitous presence within active floodplains, the detailed processes involved in the initiation of cutoffs and oxbow lakes remain incompletely understood, primarily due to the intermittent nature of such events. Furthermore, conceptual models of meander cutoff and oxbow lake formation have been primarily developed for chute cutoffs and relatively simple planform configurations. Less attention has been given to neck cutoff dynamics occurring on highly sinuous meandering rivers with complex planform morphology. During the formation of a neck cutoff on a compound elongate loop, the upstream and downstream limbs can become oriented roughly subparallel with flow in opposite directions separated by a narrow meander neck. Immediately following cutoff of this thin neck, flow from the upstream limb is sharply redirected into the downstream limb over a short distance. These conditions of tight bend flow should become more pronounced as the ratio of radius of curvature to channel width become smaller, leading to complex patterns of three-dimensional velocities that have implications for the evolution of the cutoff channel and the transformation of the abandoned bend into an oxbow lake. This paper investigates the process dynamics of neck cutoff and oxbow lake formation using detailed field measurements of three-dimensional flow velocities, channel bed topography and geotechnical analysis of the banks and floodplains from three neck cutoffs along the White River, Arkansas (USA), each representing a different stage in the morphologic evolution from cutoff to oxbow lake. Results from this study suggests that the planform geometry of neck cutoff on an elongate meander loop can influence the spatial pattern of sediment deposition within the abandoned loop leading to increased hydrologic connectivity to the main channel

  1. Georectification of historical aerial photos to track meander change in Wood River, Klamath County, Oregon

    NASA Astrophysics Data System (ADS)

    Nash, C.; Hughes, M. L.

    2010-12-01

    The Wood River in Oregon’s Upper Klamath Basin is a meandering channel draining the southeastern slopes of Crater Lake National Park. Its valley floor is heavily grazed and highly altered by a series of irrigation channels that have substantially affected the river’s spring-fed flow regime and morphology. Despite efforts to restore the river’s hydrology, very little information is available about the river’s geomorphology. Using high-resolution LIDAR data from 2004 and georectified aerial photos from 1940-2009, we analyzed meander changes along the Wood River in the geomorphic context of its valley floor and meander belt. Aerial photos were scanned to produce digital images with sub-meter pixels, then georectified with a second-order polynomial transformation. Nine or fewer ground-control points were used for each photo to achieve an overall root-mean-square error value of 0.6 - 0.7 m. The scarcity of buildings and changes in the road and fence networks over the study period required the partial use of “natural pattern matching” during photo rectification. Semi-permanent patterns of fan erosion on the upper valley floor and hydrogeomorphic wetland patterns in lower valley provided the primary bases for natural pattern matching, further aided by the use of transparency during photo overlaying. Six prototypes of meander change were identified: extension, compression, translation, rotation, compound heading, and cutoff. Of these types, extension of meanders was the most frequently occurring. However, the effects of extension were counteracted by numerous meander cutoffs, which nominally affected sinuosity, but actually shortened the channel by about 1 km, or about 3%. Cutoffs were most frequent in the upper reaches of the river, where valley slope is higher, the meander belt is wider, and accommodation space was adequate to promote relatively high initial sinuosity. In these reaches, some cutoffs appear to have initiated downstream transfers of bedload

  2. The Potential for Dams to Impact Lowland Meandering River Floodplain Geomorphology

    PubMed Central

    Marren, Philip M.; Grove, James R.; Webb, J. Angus; Stewardson, Michael J.

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an “environmental sediment regime” to operate alongside environmental flows. PMID:24587718

  3. The potential for dams to impact lowland meandering river floodplain geomorphology.

    PubMed

    Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows.

  4. The potential for dams to impact lowland meandering river floodplain geomorphology.

    PubMed

    Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows. PMID:24587718

  5. Numerical simulations of inherited sinuosity and valley entrenchment in mixed alluvial- and bedrock-banked meandering rivers

    NASA Astrophysics Data System (ADS)

    Limaye, A.; Lamb, M. P.

    2013-12-01

    Highly sinuous rivers inset in bedrock canyons have long piqued the interest of geomorphologists because this sinuous morphology evokes comparisons to more actively migrating rivers with relatively weak sediment banks. An extensive literature debates the degree to which meandering rivers in bedrock valleys have inherited their sinuosity from previous alluvial states, or instead actively maintain sinuosity through bank migration at a rate sensitive to environmental characteristics (e.g., climate and lithology). This distinction is essential to evaluating whether bedrock channel sinuosity and valley morphology can be used to infer regional base-level and climate history, or instead reflect initial conditions. Previous work has considered sinuosity inheritance to occur by river vertical incision directly translating the form of a meandering channel from its alluvial state to a bedrock-bound state, yet the rate of vertical incision required to cause this state transition is uncertain. Here we explore the hypothesis that feedbacks between channel lateral migration and vertical incision, communicated through the composition of the channel banks, may influence channel planform geometry during an alluvial-to-bedrock transition. We use a numerical model to evaluate the transient morphologic and kinematic response of an alluvial river to different vertical incision histories and initial valley configurations. The model uses a vector-based framework for bank-material tracking to precisely model feedbacks between channel lateral migration and bank strength. Model results suggest that the tendency for a channel to remain highly laterally mobile depends on the vertical incision rate, but also on the width of the valley formed by lateral channel migration: bedrock valley floors are more easily bevelled by channel sweeping within narrow valleys than for wide valleys. For cases in which the channel cannot bevel across the initial valley width, lateral variations in bank strength

  6. Spatiotemporal variations in channel changes caused by cumulative factors in a meandering river: The lower Peixe River, Brazil

    NASA Astrophysics Data System (ADS)

    Morais, Eduardo S.; Rocha, Paulo C.; Hooke, Janet

    2016-11-01

    Channel changes in meandering rivers naturally exhibit complex behaviour, and understanding the river dynamics can be challenging in environments also subject to cumulative human impacts. Planform changes were analysed on four reaches of the lower course of the Peixe River, Brazil, at decadal scales over the period 1962-2008 from aerial photographs and satellite imagery, complemented by a historical map from 1907. Analysis of the spatial and temporal patterns of channel change mechanisms and morphometry of bends and of the sinuosity and morphodynamic variations of the reaches demonstrates major changes in planform characteristics. Sinuosity in all reaches decreased from ~ 2.6 to ~ 1.7, average wavelength of bends has increased from ~ 200 to ~ 500 m, and the planform has become much simpler. Changes have been progressive from downstream to upstream, with higher intensities of processes, particularly cutoffs first in downstream reaches then more recently in upstream reaches. It is suggested that channel changes represent a morphological adjustment to human interventions, such as reservoir construction and land use. However, evidence of the autogenic behaviour of meanders is highlighted in which the existence of compound meanders reveals control over the spatial variation in the reaches. The results suggest that geomorphic thresholds associated with the compound meander formation and the bend evolution should be considered, even in impacted meandering rivers, because they exert primary controls on the spatial-temporal adjustment of channels.

  7. Chute Formation and Iterative Adjustment in Large, Sand-Bed Meandering Rivers

    NASA Astrophysics Data System (ADS)

    Grenfell, M. C.; Aalto, R. E.; Nicholas, A.

    2011-12-01

    The meandering-braided continuum is a planform manifestation of excess available river energy; a balance between the energy of flow (commonly quantified as unit steam power or shear stress), and dynamic resistance due to bed material calibre and bank strength. Single-thread meandering rivers plot in part of the continuum defined by low excess available river energy, while braided rivers plot in part of the continuum defined by high excess available river energy. Planform patterns that are transitional between single-thread meandering and braided occur where chute channel formation is prolific. In this presentation we will elucidate the morphodynamic implications of chute formation for sinuosity and planform pattern in large, sand-bed meandering rivers. We draw on the results of recent research that applied binary logistic regression analysis to determine the possibility of predicting chute initiation based on attributes of meander bend character and dynamics (Grenfell et al., accepted, ESP&L). Regression models developed for the Strickland River, Papua New Guinea (54 bends), the lower Paraguay River, Paraguay/Argentina (45 bends), and the Beni River, Bolivia (114 bends), revealed that the probability of chute initiation at a meander bend is a function of the bend extension rate (the rate at which a bend elongates). Image analyses of all rivers and field observations from the Strickland suggest that the majority of chute channels form during scroll-slough development. Rapid extension is shown to favour chute initiation by breaking the continuity of point bar deposition and vegetation encroachment at the inner bank, resulting in widely-spaced scrolls with intervening sloughs that are positively aligned with primary over-bar flow. The rivers plot in order of increasing chute activity on an empirical meandering-braided pattern continuum (Kleinhans and van den Berg, 2011, ESP&L 36) defined by potential specific stream power (ωpv) and bedload calibre (D50). Increasing

  8. River metamorphosis: insight from the comparison between individual meandering and braided threads

    NASA Astrophysics Data System (ADS)

    Metivier, Francois; Chauvet, Hugo; Devauchelle, Olivier; Barrier, Laurie; Lajeunesse, Eric; Meunier, Patrick; Zhang, Zhi; Fan, Yuting; Liu, Youcun; Dong, Zhibao

    2014-05-01

    Alluvial rivers exhibit a variety of planforms that extends between two well-defined end members: meandering and braided rivers. The mechanisms controlling the planform to the other has been the subject of intensive research and led to an almost century-long debate. The main outcomes as of today are that only two drivers control the planform morphology: sediment discharge and riparian vegetation. It is now clear that a non-cohesive gravel-bed single thread channel can only remain stable if the shear stress at its center is close to the threshold value for sediment transport. Therefore a stable channel composed of noncohesive grains can only transport a small amount of bedload. If the boundary flux is too high, the channel is no longer stable and evolves into a braided planform. Only vegetation can, to some extent, prevent this change by strengthening the river banks and enabling a single-thread channel to remain stable. One question that arises then is whether, and how a braided thread differs statistically from a meandering one. An answer would help us to understand wether a braided stream is merely a collection of single-thread streams near equilibrium or if there is something more in their morphology that distinguishes them from meandering threads. Using field data collected in the Chinese Tianshan mountains, spanning over almost five decades in discharge, we show that meandering and braided gravel bed threads have comparable morphologies under the same climate and in the same environment. There is no significant difference in width, depth or aspect ratio between the two planforms. Thus, although they transport more, braided rivers are composed of near-threshold threads like their meandering counterparts.

  9. Multiscale structure of meanders

    NASA Astrophysics Data System (ADS)

    Vermeulen, B.; Hoitink, A. J. F.; Zolezzi, G.; Abad, J. D.; Aalto, R.

    2016-04-01

    River meander planforms can be described based on wavelet analysis, but an objective method to identify the main characteristics of a meander planform over all spatial scales is yet to be found. Here we show how a set of simple metrics representing meander shape can be retrieved from a continuous wavelet transform of a planform geometry. We construct a synoptic multiple looping tree to establish the meander structure, revealing the embedding of dominant meander scales in larger-scale loops. The method can be applied beyond the case of rivers to unravel the meandering structure of lava flows, turbidity currents, tidal channels, rivulets, supraglacial streams, and extraterrestrial flows.

  10. Sediment Transport Dynamic in a Meandering Fluvial System: Case Study of Chini River

    NASA Astrophysics Data System (ADS)

    Nazir, M. H. M.; Awang, S.; Shaaban, A. J.; Yahaya, N. K. E. M.; Jusoh, A. M.; Arumugam, M. A. R. M. A.; Ghani, A. A.

    2016-07-01

    Sedimentation in river reduces the flood carrying capacity which lead to the increasing of inundation area in the river basin. Basic sediment transport can predict the fluvial processes in natural rivers and stream through modeling approaches. However, the sediment transport dynamic in a small meandering and low-lying fluvial system is considered scarce in Malaysia. The aim of this study was to analyze the current riverbed erosion and sedimentation scenarios along the Chini River, Pekan, Pahang. The present study revealed that silt and clay has potentially been eroded several parts of the river. Sinuosity index (1.98) indicates that Chini River is very unstable and continuous erosion process in waterways has increase the riverbank instability due to the meandering factors. The riverbed erosional and depositional process in the Chini River is a sluggish process since the lake reduces the flow velocity and causes the deposited particles into the silt and clay soil at the bed of the lake. Besides, the bed layer of the lake comprised of cohesive silt and clayey composition that tend to attach the larger grain size of sediment. The present study estimated the total sediment accumulated along the Chini River is 1.72 ton. The HEC-RAS was employed in the simulations and in general the model performed well, once all parameters were set within their effective ranges.

  11. Meandering stream reservoirs

    SciTech Connect

    Richardson, J.G.; Sangree, J.B.; Sneider, R.M.

    1987-12-01

    Braided stream deposits, described in a previous article in this series, and meandering stream deposits commonly are excellent reservoirs. Meandering high-sinuousity channels are found on flat alluvial plains with slopes less than 1 1/2/sup 0/ (0.026 rad). These rivers have wide ranges of discharges from low-water flow to flood stage. Two main processes are responsible for development of sand bodies. These are point-bar deposits left by channel migration, and oxbow-lake deposits left in loops of the river course abandoned when the stream cuts a new course during flooding. Extremely high floods spill over the banks and deposit sheets of very fine sand, silt, and clay onto the flood plain.

  12. Exposure of late Pleistocene Mississippi River meander-belt facies at Mt. Pleasant, Louisiana

    SciTech Connect

    Autin, W.J.; Davison, A.T.; Miller, B.J.; Day, W.J.; Schumacher, B.A.

    1988-09-01

    Exposure of a sedimentary sequence along a Mississippi River bluff at Mt. Pleasant, Louisiana, provides insight into the construction of the Prairie Terraces. This site serves as a type section for a late Pleistocene meander belt of the Mississippi River, and stratigraphic features have been traced beneath the Prairie Terraces in southeastern Louisiana. A 23.35-m measured section reveals upper units of Peoria loess and mixed loess. The described meander-belt facies are of a probable Wisconsin age and are here named the Mt. Pleasant Bluff alloformation. This age designation is based on position in the stratigraphic section, degree of preservation of sedimentary facies, character and degree of development of the upper paleosol, preservation of constructional topography beneath the loess, and correlation of this sequence to nearby sites with Wisconsin-age radiocarbon dates.

  13. Coevolution of floodplain and riparian forest dynamics on large, meandering rivers

    NASA Astrophysics Data System (ADS)

    Stella, J. C.; Riddle, J. D.; Battles, J. J.

    2012-12-01

    On large meandering rivers, riparian forests coevolve with the floodplains that support them. Floodplain characteristics such as local disturbance regime, deposition rates and sediment texture drive plant community dynamics, which in turn feed back to the abiotic processes. We investigated floodplain and riparian forest coevolution along the along the Sacramento River (California, USA), a large, mediterranean-climate river that has been extensively regulated for 70 years, but whose 160-km middle reach (Red Bluff to Colusa) retains some channel mobility and natural forest stands. Guided by maps of floodplain change over time and current vegetation cover, we conducted an extensive forest inventory and chronosequence analysis to quantify how abiotic conditions and forest structural characteristics such as tree density, basal area and biomass vary with floodplain age. We inventoried 285 fixed-area plots distributed across 19 large point bars within vegetation patches ranging in age from 4 to 107 years. Two successional trajectories were evident: (1) shifting species dominance over time within forested areas, from willow to cottonwood to walnut, boxelder and valley oak; and (2) patches of shrub willow (primarily Salix exigua) that maintained dominance throughout time. Sediment accretion was reduced in the persistent willow plots compared to the successional forest stands, suggesting an association between higher flood energy and arrested succession. Forested stands 40-60 years old were the most extensive across the chronosequence in terms of floodplain area, and supported the highest biomass, species diversity, and functional wildlife habitat. These stands were dominated by Fremont cottonwood (Populus fremontii) and reached their maxima in terms of tree size and biomass at age 50 years. The persistent willow stands reached their structural maxima earlier (32 years) and supported lower biomass. Basal area and abundance of large trees decreased in stands >90 years old

  14. Response of lateral channel dynamics of a lowland meandering river to engineering-derived adjustments - an example of the Morava River (Czech Republic)

    NASA Astrophysics Data System (ADS)

    Ondruch, Jakub; Mácka, Zdenek

    2015-11-01

    Freely meandering (quasi)natural reaches of lowland rivers represent a rare phenomenon in Central Europe. Increasing attention is currently being paid to the dynamics of quasi-natural (artificially influenced) meandering rivers as this attention represents the basic prerequisite for the development of appropriate restoration strategies on regulated rivers. This study focused on a 5.5 km long reach of the Morava River in the Strážnické Pomoraví region, Czech Republic that is characterised by quasi-natural evolution after substantial engineering adjustments were made in the first decades of the twentieth century. Based on Geographic Information Systems (GIS) analysis of aerial photographs, the spatio-temporal dynamics of bank erosion and accretion rates were quantitatively described and variables that control channel migration rates were identified. High rates of lateral shifts were localised in high sinuosity segments (sinuosity 1.17-2.37), whereas segments with very low rates were straight or formed into slightly curved bends (sinuosity 1.05-1.18). As a key factor, engineering works that influenced local river bed slope and induced a dramatic increase in bank erosion rates were identified. River engineering works induced a dramatic increase in bank erosion rate (2.19 m/year for 1938-53 and 1.47 m/year for 1953-63). An interval of approximately 25 years was needed before the erosion rates dropped back to values documented before river regulation (0.35-1.09 m/year for 1841-1938). Other important controlling variables included radius of curvature, frequency and magnitude of floods and, locally, river bank material properties and floodplain land cover.

  15. Point Bar and Overbank Deposit Storage Time Distributions in a Simulated Meandering River

    NASA Astrophysics Data System (ADS)

    Ackerman, T. R.; Pizzuto, J. E.

    2015-12-01

    Floodplain storage durations are important geologically and for managing pollutants. They provide necessary input data for sediment routing models, but the functions that describe storage are hard to define with field data. Using a meandering river model, a 36ka simulation is analyzed in 20 year time steps. Channel length, and eroded, deposited, and stored sediment volumes stabilize in under 2ka while the region explored by the river expands as time0.3. The simulated channel was 70m (3 pixels) wide and freely migrated within a 30 by 40km reach simulated with constant erodibility, and mean migration rate ±0.06 channel widths per year. No incision or aggradation was permitted. Sediment storage was partitioned by elevation. Point bar deposits are emplaced immediately as the channel moves away and comprise the lower 40% of a vertical section, while the upper 60% of the floodplain consists of vertically accreted 'overbank' deposits that accumulate with decreasing rates as elevation and distance from the channel increase. Point bar deposits have the highest probability of erosion at 80 years, and contribute 2/3 of eroded material despite representing only 40% of the floodplain volume. When eroded, vertical accretion deposits are 1.25 times older than point bar deposits. Apart from these differences, the storage distributions for both deposits are very similar, though there is much more scatter in the point bar distributions. Eroded sediment 2ka in age is well fit with a power law distribution. On average, 10% of eroded material is <80 years old, 30% from 80 - 500 years, 38% from 500 - 2000 years, 15% from 2ka to 10ka and 7% of eroded material is >10ka in age. However, the fraction older than 10ka is widely variable (0% to 30%, σ = 6.8%) in any 20 year interval. The patchiness and variability in the age of eroded sediment observed in these model results may be similar to natural settings and would be difficult to quantify or address with field measurements.

  16. Spatial variability in bank resistance to erosion on a large meandering, mixed bedrock-alluvial river

    NASA Astrophysics Data System (ADS)

    Konsoer, Kory M.; Rhoads, Bruce L.; Langendoen, Eddy J.; Best, James L.; Ursic, Mick E.; Abad, Jorge D.; Garcia, Marcelo H.

    2016-01-01

    Spatial heterogeneity in the erosion-resistance properties of the channel banks and floodplains associated with sediment characteristics, vegetation, or bedrock can have a substantial influence on the morphodynamics of meandering rivers, resulting in highly variable rates of bank erosion and complex patterns of planform evolution. Although past studies have examined the spatial variability in bank erodibility within small rivers, this aspect of the erosion-resistance properties for large rivers remains poorly understood. Furthermore, with the exception of recent numerical modeling that incorporates stochastic variability of floodplain erosional resistance, most models of meandering river dynamics have assumed uniform erodibility of the bank and floodplain materials. The present paper investigates the lateral and vertical heterogeneity in bank material properties and riparian vegetation within two elongate meander loops on a large mixed bedrock-alluvial river using several geotechnical field and laboratory methods. Additionally, the bank stability and toe-erosion numerical model (BSTEM) and repeat terrestrial LiDAR surveys are used to evaluate the capacity of the bank material properties to modify the rates and mechanisms of bank retreat. Results show that the textural properties of the bank materials, soil cohesion, and critical shear stress necessary for sediment entrainment differ substantially between the two bends and are also highly variable within each bend - laterally and vertically. Trees growing along the banks increase the resistance to erosion by contributing to the shear strength of the bank materials and are capable of increasing bank stability along a large river. Locally outcropping bedrock also influences bank erodibility in both bends. The results of this study demonstrate that spatial variability in the erosion-resistance properties of the channel banks is an important factor contributing to spatial variability in the rates and mechanisms of bank

  17. The Meandering-Braided River Pattern Transition Explained Empirically and with a 2D Morphodynamics Model

    NASA Astrophysics Data System (ADS)

    van den Berg, J. H.; Schuurman, F.; Kleinhans, M. G.; Lentink, H.

    2010-12-01

    Our objective is to understand general causes of different river channel patterns in unconfined alluvial plains. We discuss the principles and compare the performance of an empirical stream power-based classification and a physics-based bar pattern predictor. We present a careful selection of data from literature that contains rivers with discharge and median bed particle size ranging several orders of magnitude with various channel patterns and bar types, but no obvious eroding or aggrading tendency. Empirically a continuum of patterns is found for increasing specific stream power from single-thread, laterally immobile channels, meandering styles with scroll bars and with chute bars and moderately and highly braided channel patterns. Stream power is calculated with pattern-independent variables: mean annual flood, valley gradient and channel width predicted with a hydraulic geometry relation. `Thresholds', above which these patterns emerge, increase with bed sediment size. Linear bar theory predicts nature and presence of bars and bar mode, here converted to active braiding index. The most important variables are actual width-to-depth ratio and nonlinearity of bed sediment transport. Numerical modelling with the same equations as underlying the bar theory allow for nonlinear effects. We modelled hypothetical rivers over a large range of stream power and particle sizes with various choices for hydraulic roughness, sediment transport and transverse slope relations. Results agree well with the empirical diagram as well as empirical relations for bar and channel dimensions. Increasing potential specific stream power implies more energy to erode banks and indeed correlates to channels with high width-to-depth ratio. Bar theory and numerical modelling predict that such rivers develop more bars across the width (higher braiding index). At the transition from meandering to braiding weakly braided rivers and meandering rivers with chutes are found in nature and in the

  18. Meandering patterns in the wake of horizontal-axis wind and river turbines

    NASA Astrophysics Data System (ADS)

    Guala, Michele; Howard, Kevin; Singh, Arvind; Hill, Craig; Musa, Mirko; Feist, Christopher; Sotiropoulos, Fotis

    2014-11-01

    Energy harvesting devices with rotor axis oriented with the flow generate a wake which is unstable due to the complex interactions among turbulent structures from the incoming flow, root, hub and tip vortices (see Foti et al. APS/DFD 2014). Experiments in wind tunnel and open-channel flow with erodible surface show similar meandering patterns in the velocity field, which are responsible for the far wake expansion and the incoming turbulence experienced by down-wind/stream units. Wake meandering statistics were observed to depend on the operating turbine conditions (tip speed ratio), upstream device siting (turbine - turbine interaction) or specific turbine kinematics (floating turbine under waves). In addition, for wall boundary conditions defined by an erodible surface, where sand grains respond to local shear stress by moving (erosion) or settling (deposition), turbines were observed to induce dynamic topographic perturbations also exhibiting meandering patterns. This occurred in limited mobility conditions and under migrating bedforms, with large scale topographic features amplified under specific asymmetric turbine configurations. The work opens up the possibility to place turbines in complex flows optimizing their performance while maintaining, or reshaping, the surrounding topography by specific control or siting strategies. Resarch supported by NSF CAREER: CBET-1351303, IREE early career UMN, DOE Grant DE-EE0005482, NSF PFI Grant IIP-1318201.

  19. Influence of unsteady flows on pseudo-meandering river morphodynamics: An experimental study

    NASA Astrophysics Data System (ADS)

    Visconti, Francesco; Camporeale, Carlo; Ridolfi, Luca

    2010-05-01

    Natural channel patterns arise from the interaction between a turbulent open-channel flow and an erodible boundary. These interactions are usually studied by assuming a steady discharge. Nevertheless, the discharge unsteadiness is a fundamental feature of river flows. Water discharge, besides exhibiting its natural stochastic variability from daily to centenarian scale, is also influenced by river regulation and climatic changes. It is acknowledged that fluvial morphological features at short-scale are influenced by flow unsteadiness, notwithstanding a few experimental or field studies are available to clarify the modification of macroform (bends) and mesoform (bars) under unsteady discharge. Our experimental research focuses on the effect of unsteady flow on the behavior of pseudo-meandering rivers. These single-thread gravel bed rivers are characterized by a low-sinuosity planimetric shape and by a sinuous thalweg which bends around large point bars. Pseudo-meandering rivers are widespread in the piedmont area and are very interesting because several aspects of both meandering channel - presence of point bar, evolving bends, and asymmetrical cross-section - and braiding (tendency to flow diversion and to create secondary channel) interact in the same reach. We present the experimental results about the free initiation and development of the pseudo-meandering pattern, under unsteady flows. Runs with periodic step-like hydrograms characterized by a maximum, Qmax, and a minimum, Qmin, discharge, have been performed in an 18 m long and 4 m wide sand flume. Two set of parameters have been investigated, in order to simulate hydrograms with the ratio Qmax/Qmin ranging from 1.5 to 2 and the ratio of the durations of the discharges TQmin/TQmax ranging from 1 to 2. We compare these runs with the ones performed with a steady discharge equal to the mean value. All the runs have a Shields parameter two or three time greater than the critical threshold. We concentrated on the

  20. Lateral migration of the Middle Sacramento River, California

    USGS Publications Warehouse

    Brice, James Coble

    1977-01-01

    Rates and processes of lateral erosion were studied for the middle Sacramento River between Chico Landing and Colusa, Calif. , a river distance of about 50 miles which is bordered by valuable agricultural land. The study is based on comparison of maps made during 1867-1949 and on aerial photographs made during 1924-74. Meander loops migrate by downstream translation in a direction nearly perpendicular to the loop axis. Loops are cut off by straight or diagonal chutes across the meander neck. The sinuosity of the river has gradually decreased from a value of 1.56 in 1896 to 1.35 in 1974. The morphology and curvature of meander loops cut off before white settlers came to the area indicate that the river was more stable, as well as more sinuous , then than now; subsequent morphologic changes are attributed mainly to the clearing of riparian vegetation and the effects of levees in reducing the area of overflow. The bank-erosion is 1.82 acres per year per stream mile or about 15 feet per year per stream foot for the period 1896-1974. (Woodard-USGS)

  1. Sensitivity of Flow and Sediment Transport in Meandering Rivers to Scale Effects and Flow Rate

    SciTech Connect

    Shams, Mehrzad; Ahmadi, Goodarz; Smith, Duane H.

    2008-06-01

    Sensitivity of flow and sediment transport in a meandering river to variations in scaling and flow rate was studied. The FLUENT™ code was used for evaluating the river flow characteristics, including the mean velocity field and the Reynolds stress components, as well as for particle trajectory analysis. Particular attention was given to the sensitivity of the sedimentation patterns of different size particles in the river bend for various scales. Simulation studies were performed for both a model river and a physical river. The physical river was geometrically similar to the model river, with a scaling ratio of 1:100, but with identical Froude number. The flow and particle deposition patterns in the physical and model rivers were compared. It was shown that the mean flow quantities exhibit dynamic similarity, but the turbulence parameters and the particle sedimentation features in the physical river were different from the model. The secondary flows and particle transport patterns were also found to be sensitive to variation in the scale and flow rate.

  2. Dynamic meandering in response to upstream perturbations and floodplain formation

    NASA Astrophysics Data System (ADS)

    Schuurman, F.; Shimizu, Y.; Iwasaki, T.; Kleinhans, M. G.

    2016-01-01

    River meandering results from spatially alternating bank erosion and bar growth. Recent flume experiments and theory suggest that a continuous inflow perturbation is a requirement for sustained meandering. Furthermore, flume experiments suggest that bar-floodplain conversion is an additional requirement. Here, we tested the effects of continuous inflow perturbation and bar-floodplain conversion on meander migration using three numerical morphodynamic models: a 1D-model, and two 2D-models with one of them using adaptive moving grid. We focused on the interaction between bars and bends that leads to meander initiation, and the effect of different methods to model bank erosion and floodplain accretion processes on meander migration. The results showed that inflow perturbations have large effects on meander dynamics of high-sinuosity channels, with strong excitation when the inflow is periodically perturbed. In contrast, inflow perturbations have rather small effect in low-sinuosity channels. Steady alternate bars alone are insufficient to cause high-sinuosity meandering. For high-sinuosity meandering, bar-floodplain conversion is required that prevents chute-cutoffs and enhances flow asymmetry, whilst meandering with chute-cutoffs requires merely weak floodplain formation, and braiding occurs without floodplain formation. Thus, this study demonstrated that both dynamic upstream inflow perturbation and bar-floodplain conversion are required for sustained high-sinuosity meandering.

  3. Sedimentology and facies of a Mississippi River meander belt: a fluvial model based on a significant fluvial system

    SciTech Connect

    Pryor, W.A.; Jordan, D.W.

    1988-02-01

    The meander belt of the Mississippi River, in southeastern Missouri, consists of four distinct facies groups: (1) river channel/point bar, (2) chute, (3) crevasse splay/levee, and (4) abandoned channel fill. A depositional model and vertical sequences have been developed from drill cores, vibra-cores, trenches, fathometer surveys, and mapping of these principal facies. This model and he vertical sequences compare very well to ancient sequences because the Mississippi River is a large, significant river with ancient analogs.

  4. Impact of sedimentary heterogenities and sinuosity on river -aquifer exchanges in a meandering alluvial plain.

    NASA Astrophysics Data System (ADS)

    Rivière, A.; Maillot, M.; Weill, P.; Goblet, P.; Ors, F.

    2015-12-01

    A coupled sedimentary and hydrogeological model is used to quantify the impact of sedimentary heterogeneities and sinuosity on groundwater fluxes in an alluvial plain deposited by a meandering fluvial system. A 3D heterogeneous alluvial plain model is built with the stochastic/process-based model FLUMY, that simulates the evolution and the sedimentary processes of a meandering channel and its associated deposits. The resulting sedimentary blocks are translated in terms of hydrodynamic parameters (hydrofacies) and used in the 3D transient water transport model METIS. The simulated domain is 10 m-thick and at a pluri-kilometric horizontal scale, allowing considering several meanders. A head gradient between the upstream and downstream limits is imposed. The river is considered as a constant-head boundary that decreases linearly along the channel centerline. A zero-flux condition is prescribed on the other boundaries. Several cases are studied, including different degrees of sinuosity and different configurations of sediment heterogeneity: (i) a homogeneous sandy aquifer (ii) single mud-filled oxbow lake in a sandy porous media, (iii) several mud-filled oxbow lakes in a sandy porous media, and (iv) "fully" heterogeneous alluvial plain including fine-grained overbank deposits, sandy point bars, mudplugs and sandy crevasse plays. We quantify the exchange rates and directions between the river and the aquifer along the channel centerline, the piezometric evolution and the water residence time in the heterogeneous alluvial plain. This original method can improve our understanding of the functioning of alluvial corridors and evaluate the relevance of taking into account the structural heterogeneity of alluvial plains in larger regional hydrogeological models.

  5. Geophysical controls of aquifer-river exchange flow patterns in a UK lowland meandering river.

    NASA Astrophysics Data System (ADS)

    Dara, Rebwar; Krause, Stefan; Rivett, Michael

    2016-04-01

    The deposition of fine particles (clay and silt) and organic matters in alluvial sediments can substantially reduce the permeability of streambed sediments and extend towards the wider floodplain. The resulting hydraulic conductivity patterns within the streambed and floodplain have been shown to control both location as well as intensity of hyporheic exchange in many lowland rivers. The aim of the study is to investigate the variability in streambed permeability fields in an unprecedented spatial resolution and quantify the impacts on controlling hyporheic exchange fluxes in the River Tern, a UK lowland meandering stream. Geophysical surveys were conducted deploying Ground Penetrating Radar (GPR) in conjunction with geological information derived from core logs and bank exposures for mapping shallow subsurface structural heterogeneity. The GPR survey deployed a pulse EKKO pro equipped with a shielded 250 MHz antenna. For the floodplain survey, GPR profiles of 12 NE-SW and 6 NW- SE orientation profiles were taken creating a raster of approximately 10 m. The riparian terrestrial GPR surveys were accompanied by a longitudinal in channel GPR survey for which the antenna was deployed on a floating device. At locations identified to be representative for the range of streambed hydrofacies identified by GPR in investigated stream reach, multi-level mini-piezometer networks were installed in the streambed for monitoring groundwater-surface water exchange fluxes, and conducting dilution tracer tests for quantification of residence time distributions at the aquifer-river interface. Quasi-three-dimensional GPR profiles from closely spaced grids of 2D GPR data of floodplain deposits indicated a range of different radar facies and helped to delineate the type and extend of high and low conductive materials. The results of longitudinal GPR survey along a 240 m section of the river channel revealed that areas rich in low conductivity layers such as organic peat and clay lenses

  6. Tidal Meanders

    NASA Astrophysics Data System (ADS)

    Marani, M.; Lanzoni, S.; Zandolin, D.; Seminara, S.; Rinaldo, A.

    Observational evidence is presented on the geometry of meandering tidal channels evolved within coastal wetlands characterized by different tidal, hydrodynamic, to- pographic, vegetational and ecological features. New insight is provided on the ge- ometrical properties of tidal meanders, with possible dynamic implications on their evolution. In particular, it is shown that large spatial gradients of leading flow rates induce important spatial variabilities of meander wavelengths and widths, while their ratio remains remarkably constant in the range of scales of observation. This holds regardless of changes in width and wavelength up to two orders of magnitude. This suggests a locally adapted evolution, involving the morphological adjustment to the chief landforming events driven by local hydrodynamics. The spectral analysis of lo- cal curvatures reveals that Kinoshita's model curve does not fit tidal meanders due to the presence of even harmonics, in particular the second mode. Geometric parameters are constructed that are suitable to detect possible geomorphic signatures of the tran- sitions from ebb- to flood-dominated hydrodynamics, here related to the skewness of the tidal meander. Trends in skewness, however, prove elusive to measure and fail to show detectable patterns. We also study comparatively the spatial patterns of evolu- tion of the ratios of channel width to depth, and the ratio of width to local radius of curvature. Interestingly, the latter ratio exhibits consistency despite sharp differences in channel incision. Since the degree of incision, epitomized by the width-to-depth ratio, responds to the relevant erosion and migrations mechanisms and is much sen- sitive to vegetation and sediment properties, it is noticeable that we observe a great variety of landscape carving modes and yet recurrent planar features like constant width/curvature and wavelength/width ratios.

  7. Hydrological controls on the morphogenesis of low-energy meanders (Cher River, France)

    NASA Astrophysics Data System (ADS)

    Dépret, Thomas; Gautier, Emmanuèle; Hooke, Janet; Grancher, Delphine; Virmoux, Clément; Brunstein, Daniel

    2015-12-01

    River restoration is a key-issue for European hydrosystems that were modified over centuries by human activities. This is particularly true for numerous low energy rivers flowing in the plateaus of Western Europe. Because of this limited energy, their potential in terms of autogenic restoration a priori appears strongly restricted. This study examines the conditions under which the morphogenesis on one of these systems occurs in relation to various hydrologic conditions. Two complementary approaches are combined on three reaches of the meandering Cher River (France). Firstly, we examine at a pluri-decadal scale the control of duration, frequency and intensity of floods on the planimetric erosion (bank retreat mainly). Secondly, we estimate the range of effective discharge for bedload transport. The results show that the morphogenesis is controlled by low magnitude hydrological events. Two major controlling factors are suggested: low differential of energy between small and large floods, peculiar to low energy rivers of mid-latitude, and low critical discharges for lateral erosion and bedload mobilization. For these reasons, the ability of the alluvial Cher River to self-restore its fluvial dynamics seems to be relatively high.

  8. A New Stochastic Modeling of 3-D Mud Drapes Inside Point Bar Sands in Meandering River Deposits

    SciTech Connect

    Yin, Yanshu

    2013-12-15

    The environment of major sediments of eastern China oilfields is a meandering river where mud drapes inside point bar sand occur and are recognized as important factors for underground fluid flow and distribution of the remaining oil. The present detailed architectural analysis, and the related mud drapes' modeling inside a point bar, is practical work to enhance oil recovery. This paper illustrates a new stochastic modeling of mud drapes inside point bars. The method is a hierarchical strategy and composed of three nested steps. Firstly, the model of meandering channel bodies is established using the Fluvsim method. Each channel centerline obtained from the Fluvsim is preserved for the next simulation. Secondly, the curvature ratios of each meandering river at various positions are calculated to determine the occurrence of each point bar. The abandoned channel is used to characterize the geometry of each defined point bar. Finally, mud drapes inside each point bar are predicted through random sampling of various parameters, such as number, horizontal intervals, dip angle, and extended distance of mud drapes. A dataset, collected from a reservoir in the Shengli oilfield of China, was used to illustrate the mud drapes' building procedure proposed in this paper. The results show that the inner architectural elements of the meandering river are depicted fairly well in the model. More importantly, the high prediction precision from the cross validation of five drilled wells shows the practical value and significance of the proposed method.

  9. Channel dynamics and habitat complexity in a meandering, gravel-bed river

    NASA Astrophysics Data System (ADS)

    Harrison, L. R.; Legleiter, C. J.; Pecquerie, L.; Dunne, T.

    2009-12-01

    River channel dynamics play an important role in creating and maintaining diverse habitat conditions for multiple life stages of aquatic organisms. As a result, many river restoration projects seek to re-establish ecosystems in which an enhanced degree of habitat complexity is sustained through natural fluvial processes of flow, sediment transport, and channel change. Few field cases have effectively quantified the evolution of channel morphology and habitat complexity in restored rivers, however, and the outcomes of restoration actions remain difficult to predict. Our objective was to quantify the extent to which morphology, flow complexity and salmonid spawning and rearing habitat develop from the simplified initial conditions commonly observed in re-configured meandering channels. Using a time-series of topographic data, we measured rates of morphologic change in a recently restored gravel-bed reach of the Merced River, California, USA. We constructed two-dimensional (2D) hydrodynamic models to quantify how the evolving morphology influenced hydraulic conditions, flow complexity and suitability for Chinook salmon spawning and rearing. Following two large flood events, point bar development led to order-of-magnitude increases in modeled flow complexity, as quantified via the metrics of kinetic energy gradient, vorticity and hydraulic strain. On a bend-averaged scale, morphologic changes produced up to a two-fold increase in flow circulation, indicating a direct linkage between geomorphic processes and the development of habitat complexity at both the local (1.0 m2 grid cell) and meander wavelength scale. Habitat modeling indicated that the availability of Chinook salmon spawning habitat has increased over time, whereas the majority of the reach provides low-medium quality rearing habitat for juvenile salmonids, primarily due to a lack of low velocity refuge zones. These results demonstrate the ability of geomorphic processes to increase flow complexity and

  10. Analysis of river planforms in the New Madrid region and possible relations to tectonic warping across the loess bluffs and within the meander belt of the Mississippi River

    SciTech Connect

    Johnson, K.A.; Mayer, L. . Dept. of Geology)

    1993-03-01

    Stream channel planforms measured from such streams as the Hatchie (H), L'Anguille (LA), St. Francis, White (W) and Little Red (LR) rivers provide a way to study influences of topographic warping between the loess bluffs that bound the Mississippi river valley. Planforms are analyzed using sinuosity, Richardson analysis, and pattern. Pattern changes include transitions from braided to meandering and meandering to straight. Sinuosities of the W and LR rivers show a transition from low sinuosity, [1.3, 1.4] to higher sinuosity [2.6, 2.8], over a short distance, as they cross the bluffs from the uplands to the Western Lowlands. On the east, the Hatchie changes from a braided to meandering pattern upon crossing the bluffs. Its sinuosity varies from a low of about 1.4 to a high of 2.2, coincident with a marsh area. The LA river flows on the west side of Crowley's Ridge and is paralleled by the St. Francis river on the east. These rivers, with very different drainage areas and sinuosities, show matching meander bends at similar wavelengths along Crowley's Ridge. The bends are about 10 km in 1/2 wavelength suggesting some extraordinary influence on pattern perpendicular to the ridge. Richardson analysis indicates that features with a 1/2 wavelength of 2 km may control several rivers' bending patterns. These features are analyzed to determine their spatial relations with one another.

  11. The performance of the Hydromorphological Index of Diversity (HMID) in a hydropower affected meandering river

    NASA Astrophysics Data System (ADS)

    Stähly, Severin; Bourqui, Pierre; Franca, Mario J.; Robinson, Christopher; Schleiss, Anton J.

    2016-04-01

    More than half of the Swiss electricity is produced by hydropower. Large price fluctuations cause severe hydropeaking flow regimes due to corresponding production fluctuations, which undisputedly have a negative impact on aquatic biota. Water diversion due to dams on the other hand imposes downstream residual flow regimes. The absence of flood events and regular sediment supply disrupts sediment dynamics and disconnects floodplains, which are habitats of high value, from its main channel. The residual-flow controlled reach at the Sarine river in western Switzerland is the subject of the present study. The Sarine meanders strongly and the river reach under analysis has a bed incision of locally more than 100 m. Its incision provokes the isolation of the river which is consequently minimally touched by human structures and shows a natural geomorphology. Since the construction of a dam upstream this reach in 1948, aiming at the water abstraction to hydropower, vegetation could establish and the active floodplain decreased its area, as airborne images show. Nevertheless, it is classified as a floodplain of national importance and it has been under protection since 1992. It is supposed to be a valuable habitat for a wide range of organisms. The Hydromorphological Index of Diversity (HMID) is a simple tool for quantifying the habitat richness in a river reach, taking into account the mean values and the variation of water depth and flow velocity. For channelized rivers, HMID values from up to 5 are expected, while morphological pristine sites with a high spatial variability of water depth and velocity show values of 9 or higher. For the residual flow of the Sarine River, flow depth and velocity were measured using ADCP and ADV. The results are compared with a nearby natural reference river and the outcome of a 2D numerical simulation. Finally, the behaviour and limitations of the HMID, in a hydropower affected river, are discussed. In the close future an artificial flood

  12. Mediative adjustment of river dynamics: The role of chute channels in tropical sand-bed meandering rivers

    NASA Astrophysics Data System (ADS)

    Grenfell, M. C.; Nicholas, A. P.; Aalto, R.

    2014-03-01

    This paper examines processes of chute channel formation in four tropical sand-bed meandering rivers; the Strickland and Ok Tedi in Papua New Guinea, the Beni in Bolivia, and the lower Paraguay on the Paraguay/Argentina border. Empirical planform analyses highlight an association between meander bend widening and chute initiation that is consistent with recent physics-based modelling work. GIS analyses indicate that bend widening may be driven by a variety of mechanisms, including scour and cutbank bench formation at sharply-curving bends, point bar erosion due to cutbank impingement against cohesive terrace material, rapid cutbank erosion at rapidly extending bends, and spontaneous mid-channel bar formation. Chute channel initiation is observed to be predominantly associated with two of these widening mechanisms; i) an imbalance between cutbank erosion and point bar deposition associated with rapid bend extension, and ii) bank erosion forced by spontaneous mid-channel bar development. The work extends previous empirical analyses, which highlighted the role of bend extension (elongation) in driving chute initiation, with the observation that the frequency of chute initiation increases once bend extension rates and/or widening ratios exceed a reach-scale threshold. A temporal pattern of increased chute initiation frequency on the Ok Tedi, in response to channel steepening and mid-channel bar development following the addition of mine tailings, mirrors the inter- and intra-reach spatial patterns of chute initiation frequency on the Paraguay, Strickland and Beni Rivers, where increased stream power and sediment load are associated with increased bend extension and chute initiation rates. The process of chute formation is shown to be rate-dependent, and the threshold values of bend extension and widening ratio for chute initiation are shown to scale with measures of river energy, reminiscent of slope-ratio thresholds in river avulsion. Furthermore, Delft3D simulations

  13. Einstein's meanders

    NASA Astrophysics Data System (ADS)

    Lomnitz, C.

    2007-05-01

    What does Einstein have to do with subduction? Good question. Peaceful Lake Budi, lying at the heart of an Indian reservation in the Deep South of Chile, had subsided by two meters in the 1960 mega-thrust earthquake. This unique South American salt lake was hiding an awful secret: it was actually an oxbow, not a lake. But Einstein had realized in 1926 that meanders are natural freaks. Rivers will not flow uphill, yet - he claimed - they don't flow down the path of steepest descent either. This anomaly was put at the doorstep of a weak Coriolis Force. Thus Einstein problematized the dilemma of the earth sciences. How can a non-force produce margin-parallel compression in a convergent margin where extension is expected? In fact, where does the energy for meander formation come from? Good question . . . Even Wikipedia knows that Coriolis is not a “force” but an “effect”. So is the obliquity of plate convergence in subduction. Where did Einstein err, and where was he a pioneer? Coastal ablation plus alternating subsidence and emergence in giant earthquakes may yield an answer. Einstein, A. (1926). Die Ursache der Maeanderbildung der Flusslaeufe und das sogenannte Baersche Gesetz, Naturwissenschaften, 14, fascicle II.

  14. Empirical analysis of the spatial structure of meander evolution: Insights into the development of compound loops

    NASA Astrophysics Data System (ADS)

    Guneralp, I.; Rhoads, B. L.

    2009-12-01

    Complex meander forms such as compound loops or multi-lobes are common features of natural meandering rivers. Despite a large body of research on river meandering, the development of compound loops is not fully understood. An improved understanding of the development of compound loops is crucial due to the importance of planform migration dynamics in floodplain development and landscape evolution. Indeed, such an understanding would facilitate the mitigation of river hazards created by bank erosion and channel migration and help develop more effective river management strategies and sustainable river restoration practices. The purpose of this study is to explain the complex interactions between the planform curvature and migration dynamics that result in the development of compound loops. For this purpose, we evaluated empirically the effect of planform curvature on the migration dynamics of several natural meander-trains with varying degrees of planform complexity and a set of complex meander bends of a meander-train. In the analysis of the meander-trains, we employed a dynamical systems approach and used the capabilities of Discrete Signal Processing, which allows for the empirical derivation of the spatial relation between the planform curvature and migration rate. Data for the meander-trains extracted from multi-temporal aerial photography. In the analysis of the complex meander bends, we used phase-space diagrams developed using a refined version of an existing empirical-analysis method and newly developed analytical technique of planform characterization that overcome the limitations of past work. The results of the study suggest that the spatial structure of the curvature effect on the migration rate is complex, characterized by multiple behavior modes consisting of exponential decay as well as oscillatory structures. As the planform evolves to a complex geometry that contains compound loops, the dominant behavior mode changes from pure exponential decay to

  15. Fates of pollutants from uranium mining in floodplain of a meandering river (the Ploucnice, Czech Republic)

    NASA Astrophysics Data System (ADS)

    Matys Grygar, Tomas; Elznicova, Jitka; Majerova, Lucie; Babek, Ondrej; Kiss, Timea; Havelcova, Martina; Hosek, Michal

    2014-05-01

    tens of km downstream of the mining area). Several hotspots were formed behind the end of the channelised river reach downstream from the mining area. The analyses of the pollution hotspots conducted by other researchers in 1990s and our novel results show that maximal pollutant gamma activity (mainly U and Ra-226) in these hotspots has been transported from a meander (channel) belt towards the distal floodplain. Downstream transport (secondary pollution) from the hotspots is demonstrated by considerable Zn, Ni and U enrichment in the deposits of 2013 summer flood (25 years after termination of the primary pollution) and by the fact, that enrichment factors of Zn, Ni and U in the floodplain sediments downstream of the hotspots has still not started to decline. The persistence of the pollution of the floodplain sediments is in contrast with the activity of the Ploučnice River water, which dropped down in 1989 and afterwards to the levels from the period before the start of the uranium mining.

  16. A backwards-in-time Lagrangian framework for extraction of meander bend dynamics: use in meander classification, process diagnostics, and model comparison

    NASA Astrophysics Data System (ADS)

    Schwenk, J.; Lanzoni, S.; Foufoula-Georgiou, E.

    2013-12-01

    Physically based river meander migration models have grown in popularity and complexity since the pioneering work of Ikeda, Parker, and Saswe in 1981. Numerical meander models have proven valuable for understanding river meander dynamics by providing highly resolved temporal and spatial series of physiographic and morphodynamic properties that are difficult or impossible to observe from real meandering rivers. Analyses of such model outputs typically focus on either reachwide (e.g. sinuosity) or pointwise (e.g. local migration rates) measures. We propose here a framework that bridges the gap between holistic and reductionist approaches to river meandering. This research introduces a new method for identifying and tracking individual meanders ('atoms') from cutoff to inception. An atom is a river reach that evolves in time and eventually intersects itself to become an oxbow lake. Typically individual meander extractions use inflection points to demarcate meander end-points, but automated inflection detection is susceptible to spurious flexes along the centerline. We propose a different approach based on tracking cutoff nodes backwards in time thereby avoiding detection problems and making an atom's dynamics easily accessible. A classification scheme is developed that separates extracted atoms into three types of increasing complexity. Type I atoms are simple, single-loop meander bends; type II atoms contain complex, single-loop bends; and type III atoms consist of compound or multiple meanders. The distinct dynamic behavior of each atom type is explored through individual and ensemble dynamics, e.g. average growth rate, average migration rate, or statistics of local curvature series. Analyses reveal new insights that relate process and form and explore the effect of local versus non-local influences on meander growth. The utilized river migration model represents the most basic physical processes that drive river migration--i.e., channel cutoff and channel migration

  17. Earth meandering

    NASA Astrophysics Data System (ADS)

    Asadiyan, H.; Zamani, A.

    2009-04-01

    In this paper we try to put away current Global Tectonic Model to look the tectonic evolution of the earth from new point of view. Our new dynamic model is based on study of river meandering (RM) which infer new concept as Earth meandering(EM). In a universal gravitational field if we consider a clockwise spiral galaxy model rotate above Ninety East Ridge (geotectonic axis GA), this system with applying torsion field (likes geomagnetic field) in side direction from Rocky Mt. (west geotectonic pole WGP) to Tibetan plateau TP (east geotectonic pole EGP),it seems that pulled mass from WGP and pushed it in EGP due to it's rolling dynamics. According to this idea we see in topographic map that North America and Green land like a tongue pulled from Pacific mouth toward TP. Actually this system rolled or meander the earth over itself fractaly from small scale to big scale and what we see in the river meandering and Earth meandering are two faces of one coin. River transport water and sediments from high elevation to lower elevation and also in EM, mass transport from high altitude-Rocky Mt. to lower altitude Himalaya Mt. along 'S' shape geodetic line-optimum path which connect points from high altitude to lower altitude as kind of Euler Elastica(EE). These curves are responsible for mass spreading (source) and mass concentration (sink). In this regard, tiltness of earth spin axis plays an important role, 'S' are part of sigmoidal shape which formed due to intersection of Earth rolling with the Earth glob and actual feature of transform fault and river meandering. Longitudinal profile in mature rivers as a part of 'S' curve also is a kind of EE. 'S' which bound the whole earth is named S-1(S order 1) and cube corresponding to this which represent Earth fracturing in global scale named C-1(cube order 1 or side vergence cube SVC), C-1 is a biggest cycle of spiral polygon, so it is not completely closed and it has separation about diameter of C-7. Inside SVC we introduce cone

  18. Stratification effects on flow field and bed topography in meandering rivers

    NASA Astrophysics Data System (ADS)

    Bolla Pittaluga, M.

    2010-12-01

    and eddy diffusivity, enhances significantly the vertical distribution of lateral velocity. Next, we investigate whether the point bar pattern in the inner bank and pool in the outer bank typically observed in meandering rivers may be significantly affected by the stratification effect. With the help of the Exner equation we show that, in the ideal case analyzed here, namely a uniform and steady flow in a constant curvature channel, stratification gives rise to steeper lateral bed profiles with respect to the unstratified case.

  19. High precision terrestrial laser scanning : measuring the individual impact of floods and landslides on meandering bedrock river dynamics (Rangitikei river, New-Zealand)

    NASA Astrophysics Data System (ADS)

    Lague, D.; Bonnet, S.; Brodu, N.; Davies, T.; Leroux, J.

    2012-04-01

    Actively incising and meandering bedrock rivers are an ubiquitous feature of mountain belts, but the mechanisms leading to their formation and evolution are still poorly understood. Part of the problem lies in our limited ability to quantify in situ the mechanisms governing the dynamics of straight bedrock rivers (tool-cover effects, stochastic sediment supply and discharge effects, roughness effects,...). But the rapid and spatially variable rates of bank erosion in meanders also lead to potentially more complex hillslope-channel interactions than in straight river. Terrestrial laser scanner has the potential to shed new light on these interactions and to capture over large surfaces the impact of individual flood and landsliding events. Given the small changes of surface position that must be detected for even the largest rates of bedrock erosion (~ 5-10 mm/yr) and the 3D geometrical complexity of bedrock meanders, specific survey approaches and post-processing algorithms must be developed. To this end, we started to perform repeated Terrestrial Laser Scanner (TLS) surveys of actively incising meanders in the Rangitikei river (New-Zealand) in 2009. The Rangitikei river is incising weakly consolidated mudstone at an average rate of 5 mm/yr since 15 kyr and has developed a very sinuous meandering pattern with several cut-off bedrock meanders. Lateral undercutting of 100 m high cliffs generates failures of up to hundred of meters. Alluvial material consists of coarse resistant material (D50 ~20 cm) sourced from upstream, and large boulders locally derived from rockfalls. Exposed bedrock is rare on the bed but shows that abrasion, weathering by wetting-drying cycles and plucking are important incision mechanisms. Six TLS surveys were performed at bi-monthly to yearly intervals with a Leica Scanstation 2 in 5 reaches of variable planform curvature. Survey length varies from 300 m to 1200 m and point spacing from ~ 5 mm to 5 cm. Point clouds were co-registered between

  20. Is sinuosity a function of slope and bankfull discharge? - A case study of the meandering rivers in the Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Petrovszki, J.; Timár, G.; Molnár, G.

    2014-11-01

    Pre-regulation channel sinuosities of the meandering rivers of the Pannonian Basin are analysed in order to define a mathematical model to estimate the influence of the bankfull discharge and the channel slope on them. As a primary database, data triplets of slope, discharge and sinuosity values were extracted from historical and modern datasets and pre-regulation historical topographic maps. Channel slope values were systematically modified to estimate figures valid before the river regulation works. The bankfull discharges were estimated from the average discharges using a robust yet complex method. The "classical" graphs of Leopold and Wolman (1957), Ackers and Charlton (1970b) and Schumm and Khan (1972) were compiled to a set up a theoretical surface, whose parameters are estimated by the real values of the above database, containing characteristics of the Pannonian Basin rivers. As a result it occurred that there is a two-dimensional function of the bankfull discharges, which provides a good estimation of the most probable sinuosity values of the rivers with the given slope and discharge characteristics. The average RMS error of this estimation is around 15% on this dataset and believed to be the effect of the non-analysed changes in the sediment discharge and size distribution.

  1. Human modification of a large meandering Amazonian river: genesis, ecological and economic consequences of the Masisea cutoff on the central Ucayali, Peru.

    PubMed

    Coomes, Oliver T; Abizaid, Christian; Lapointe, Michel

    2009-05-01

    Evidence is mounting regarding the significant extent and scope of long-term human modification of "pristine nature" in the neotropics. In Amazonia, recent studies point to the landscape imprint of human activity that has transformed the forests, savannas, soils, and waterways of the basin. In this report, we describe a massive meander cutoff in the Peruvian Amazon along the Ucayali River--the fifth-longest river in the Amazon basin--that was triggered by small-scale human actions and resulted in significant ecological and economic consequences for the region. The modern case of the Masisea cutoff-near the Amazonian port city of Pucallpa, Peru (285,000 inhabitants)-indicates that humans using simple tools can play a major role in transforming large meandering rivers and their floodplains.

  2. Meandering channels without vegetation: Examples from Nevada and Chile

    NASA Astrophysics Data System (ADS)

    Matsubara, Y.; Howard, A. D.; Burr, D. M.; Williams, R. M.; Moore, J. M.

    2012-12-01

    We report on a study motivated by the occurrence of highly sinuous, actively migrating paleochannels on Mars. Highly sinuous, unconfined meanders require small aspect ratios, which in turn require cohesive channel banks. This cohesion is obtained most commonly by vegetation cover coupled with high suspended sediment loading. The dominant role of vegetation in meandering is reflected in the difficulty in creating highly sinuous channels in flume experiment without introduction of vegetation. The occurrence of strongly meandering channels on Mars suggests meanders can develop in the absence of vegetation. The main objective of our study is to understand the processes of meander evolution in non-vegetated surfaces. We have studied two terrestrial sites in which meandering channels form where vegetation is sparse and has little influence on bank erodibility or point-bar deposition, indicating that there must be other mechanisms creating bank cohesion. One mechanism is stabilization of point-bar deposits by mud drapes. The Quinn River in Nevada is a sinuous channel that flows through fine lacustrine sediments on the floor of paleolake Lahontan resulting in the river having both bed and bank composed of sediment containing least 40% silt/clay. In addition to abundant mud, high salt content of the river water encourages flocculation and settling of fine sediment; thus both high clay/silt content and salt work together at the Quinn River to maintain a small aspect ratio. In contrast to the Quinn River, meandering channels on alluvial fans in the Atacama Desert in northern Chile are deposited by flows originating from the foothills of the Andes Mountains where sediments are coarser and more variable in size. Like Quinn River both fine sediments and salts contribute to meandering. The bank cohesion is provided by mudflows or hyperconcentrated flows creating bank drapes as well as extensive overbank levees which harden to adobe-like consistency. The Atacama Desert is rich in

  3. Geomorphic adjustment to hydrologic modifications along a meandering river: Implications for surface flooding on a floodplain

    NASA Astrophysics Data System (ADS)

    Edwards, Brandon L.; Keim, Richard F.; Johnson, Erin L.; Hupp, Cliff R.; Marre, Saraline; King, Sammy L.

    2016-09-01

    Responses of large regulated rivers to contemporary changes in base level are not well understood. We used field measurements and historical analysis of air photos and topographic maps to identify geomorphic trends of the lower White River, Arkansas, USA, in the 70 years following base-level lowering at its confluence with the Mississippi River and concurrent with flood control by dams. Incision was identified below a knickpoint area upstream of St. Charles, AR, and increases over the lowermost ~90 km of the study site to ~2 m near the confluence with the Mississippi River. Mean bankfull width increased by 30 m (21%) from 1930 to 2010. Bank widening appears to be the result of flow regulation above the incision knickpoint and concomitant with incision below the knickpoint. Hydraulic modeling indicated that geomorphic adjustments likely reduced flooding by 58% during frequent floods in the incised, lowermost floodplain affected by backwater flooding from the Mississippi River and by 22% above the knickpoint area. Dominance of backwater flooding in the incised reach indicates that incision is more important than flood control on the lower White River in altering flooding and also suggests that the Mississippi River may be the dominant control in shaping the lower floodplain. Overall, results highlight the complex geomorphic adjustment in large river-floodplain systems in response to anthropogenic modifications and their implications, including reduced river-floodplain connectivity.

  4. Floodplain architecture of an actively meandering river (the Ploučnice River, the Czech Republic) as revealed by the distribution of pollution and electrical resistivity tomography

    NASA Astrophysics Data System (ADS)

    Matys Grygar, T.; Elznicová, J.; Tůmová, Š.; Faměra, M.; Balogh, M.; Kiss, T.

    2016-02-01

    The aim of this study was to describe the floodplain architecture of the Ploučnice River, a naturally meandering river in the Czech Republic, using manual drill coring, the element analysis of sediments, and electrical resistivity tomography (ERT). The Ploučnice River has received diffuse pollution since the early twentieth century (mainly Pb) followed by a prominent, temporally well-defined pollution pulse from uranium mining in the 1970s and 1980s (mainly U and 226Ra). The pollution created a chemostratigraphic (temporal) framework for overbank fines. We used geographical information systems (GIS) to describe the channel's dynamics and visualise fluvial landforms. We sampled and analysed the finest floodplain sediments in the top 1 to 2 m of the floodplain fill (silty and sandy deposits), and we used ERT to visualise bodies of coarser and deeper strata at depths down to ~ 3 m. Several limits of ERT imaging have been found by a comparison of the resistivity domains with lithological descriptions of the cores: several decimetre-thick strata were not revealed (they are below the spatial resolution of that method), and humidity affected the results that were obtained in the topmost strata. The space for deposition of fluvial sediments in the Ploučnice River is being created by (1) natural lateral shifts in the channel (up to 0.5 m/year); (2) meander loop development and cutoffs at the timescale of decades to centuries and spatial scale of up to ~ 1/4 of the floodplain width; and (3) more substantial reorganisation of the channel structure by avulsions, probably at the timescale of centuries. These processes continuously create space for the deposition of overbank fines on the top of former point bars and in swales and abandoned channels. As a consequence of the speed of the channel shifts, at least 80% of the fine-grained top of the floodplain fill (overbank fines) was reworked over approximately three centuries.

  5. Low sinuosity and meandering bedload rivers of the Okavango Fan: channel confinement by vegetated levées without fine sediment

    NASA Astrophysics Data System (ADS)

    Stanistreet, I. G.; Cairncross, B.; McCarthy, T. S.

    1993-05-01

    The river systems of the Okavango Fan negate present fluviological perceptions that fluvial geometry is primarily dependent upon the type of sediment load being carried by the river. In northwest Botswana, meandering and low sinuosity rivers, both of which may show anastomosis, are distinctly bedload in character. This is mainly because of a restricted source of clastic sediment, consisting of aeolian sand from the Tertiary to Recent Kalahari Basin. All that seems to be required, therefore, to control low sinuosity and meandering geometries is adequate confinement of channels. In the study examples this is provided by heavily vegetated levées comprising peat, formed from and colonised by a Cyperus papyrus dominated flora: fine sediment plays almost no role in the confinement process. Active and abandoned examples of low sinuosity river channels were studied. An inversion of topography develops in the latter, caused by the low survival probability of metres thick peat levées. Desiccation and burning of peat ultimately form a degraded ash layer only tens of centimetres thick. The channel sand then stands as a ridge rising above the surrounding fan surface. In both examples studied, no crevasse splays occur, but hippopotami trails breach the levées to form minor distributary channels which become filled with sand. The sand ultimately grades backwards to plug the breach. Meander belts are also developed, particularly in the upper fan and entry corridor. Cut banks incise into the sand substrate and scroll bar topographies can be discerned beneath their peat cover. Fine sediment plays no role in the confinement of these channels, which are maintained by peat levées similar to those encountered in the low sinuosity river channels. The recognition of these bedload low sinuosity and meandering river channels now completes the matrix, whereby any geometry of river channel can be developed in bedload, mixed load and suspended load rivers. Important aspects of the modern

  6. From meander bend to oxbow lake: flow, channel morphology and sedimentology of an evolving chute cutoff on the Wabash River, IL-IN

    NASA Astrophysics Data System (ADS)

    Zinger, J. A.; Rhoads, B. L.; Best, J. L.; Johnson, K.

    2012-12-01

    Chute channels develop on meandering rivers in a wide variety of environments, and in many cases result in bend cutoff and formation of an oxbow lake. During the transition from active meander bend to oxbow lake, the chute channel and original bend create a paired bifurcation-confluence unit. Here, we present field documentation of the evolving flow structure within a recent chute cutoff on the Wabash River, IL-IN, focusing on the bifurcation located on the upstream limb of the original bend. Previous studies indicate that this is the location of greatest sedimentation rates prior to complete plugging of the bend (e.g. Shields & Abt, 1989). We seek to isolate the fundamental processes causing rapid sedimentation in the upstream limb of the bend, using repeated hydroacoustic measurements of bed elevation and three-dimensional flow velocity at several key cross-sections. We also employ differential GPS surveys of channel banklines, analysis of aerial photographs and sampling of sediment on exposed bars at low flow, to aid interpretations of the cross-sectional data. This paper will detail the co-evolution of flow structure and channel morphology at this site and examine the coherent patterns of erosion and deposition responsible for oxbow lake formation. Reference: Shields, FD; Abt, SR (1989). Sediment deposition in cutoff meander bends and implications for effective management. Regulated Rivers: Research & Management 4, 381-396.

  7. Flow structure and channel morphodynamics of meander bend chute cutoffs: A case study of the Wabash River, USA

    NASA Astrophysics Data System (ADS)

    Zinger, Jessica A.; Rhoads, Bruce L.; Best, James L.; Johnson, Kevin K.

    2013-12-01

    paper documents the three-dimensional structure of flow and bed morphology of two developing chute cutoffs on a single meander bend on the lower Wabash River, USA, and relates the flow structure to patterns of morphologic change in the evolving cutoff channels. The upstream end of the cutoff channels is characterized by: (1) a zone of flow velocity reduction/stagnation and bar development in the main channel across from the cutoff entrance, (2) flow separation and bar development along the inner (left) bank of the cutoff channel immediately downstream from the cutoff entrance, and (3) helical motion and outward advection of flow momentum entering the cutoff channel, leading to erosion of the outer (right) bank of the cutoff channel. At the downstream end of the cutoff channels, the major hydrodynamic and morphologic features are: (1) flow stagnation along the bank of the main channel immediately upstream of the cutoff channel mouth, (2) convergence of flows from the cutoff and main channels, (3) helical motion of flow from the cutoff, (4) a zone of reduced velocity along the bank of the main channel immediately downstream from the cutoff channel mouth, and (5) development of a prominent bar complex that penetrates into the main channel and extends from the stagnation zone upstream to downstream of the cutoff mouth. These results provide the basis for a conceptual model of chute-cutoff dynamics in which the upstream and downstream ends of a cutoff channel are treated as a bifurcation and confluence, respectively.

  8. Spatial variability in floodplain resistance to erosion on a large meandering, mixed bedrock-alluvial river

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial heterogeneities of the erosion-resistance properties of the channel banks and floodplains, such as grain size characteristics and the presence of vegetation and bedrock, can have a substantial influence on river morphodynamics, resulting in complex planform geometries and highly variable rat...

  9. A vector-based method for bank-material tracking in coupled models of meandering and landscape evolution

    NASA Astrophysics Data System (ADS)

    Limaye, Ajay B. S.; Lamb, Michael P.

    2013-12-01

    channels commonly migrate laterally and interact with banks of different strengths—an interplay that links geomorphology and life and shapes diverse landscapes from the seafloor to planetary surfaces. To investigate feedbacks between meandering rivers and landscapes over geomorphic timescales, numerical models typically represent bank properties using grids; however, this approach produces results inherently dependent on grid resolution. Herein we assess existing techniques for tracking landscape and bank-strength evolution in numerical models of meandering channels and show that grid-based models implicitly include unintended thresholds for bank migration that can control simulated landscape evolution. Building on stratigraphic modeling techniques, we develop a vector-based method for land surface- and subsurface-material tracking that overcomes the resolution-dependence inherent in grid-based techniques by allowing high-fidelity representation of bank-material properties for curvilinear banks and low channel lateral migration rates. We illustrate four specific applications of the new technique: (1) the effect of resistant mud-rich deposits in abandoned meander cutoff loops on meander belt evolution; (2) the stratigraphic architecture of aggrading, alluvial meandering channels that interact with cohesive-bank and floodplain material; (3) the evolution of an incising, meandering river with mixed bedrock and alluvial banks within a confined bedrock valley; and (4) the effect of a bank-height dependent lateral-erosion rate for a meandering river in an aggrading floodplain. In all cases the vector-based approach overcomes numerical artifacts with the grid-based model. Because of its geometric flexibility, the vector-based material tracking approach provides new opportunities for exploring the coevolution of meandering rivers and surrounding landscapes over geologic timescales.

  10. Hyporheic Exchange Flows and Biogeochemical Patterns near a Meandering Stream: East Fork of the Jemez River, Valles Caldera National Preserve, New Mexico

    NASA Astrophysics Data System (ADS)

    Christensen, H.; Wooten, J. P.; Swanson, E.; Senison, J. J.; Myers, K. D.; Befus, K. M.; Warden, J.; Zamora, P. B.; Gomez, J. D.; Wilson, J. L.; Groffman, A.; Rearick, M. S.; Cardenas, M. B.

    2012-12-01

    A study by the 2012 Hydrogeology Field Methods class of the University of Texas at Austin implemented multiple approaches to evaluate and characterize local hyporheic zone flow and biogeochemical trends in a highly meandering reach of the of the East Fork of the Jemez River, a fourth order stream in northwestern New Mexico. This section of the Jemez River is strongly meandering and exhibits distinct riffle-pool morphology. The high stream sinuosity creates inter-meander hyporheic flow that is also largely influenced by local groundwater gradients. In this study, dozens of piezometers were used to map the water table and flow vectors were then calculated. Surface water and ground water samples were collected and preserved for later geochemical analysis by ICPMS and HPLC, and unstable parameters and alkalinity were measured on-site. Additionally, information was collected from thermal monitoring of the streambed, stream gauging, and from a series of electrical resistivity surveys forming a network across the site. Hyporheic flow paths are suggested by alternating gaining and losing sections of the stream as determined by stream gauging at multiple locations along the reach. Water table maps and calculated fluxes across the sediment-water interface also indicate hyporheic flow paths. We find variability in the distribution of biogeochemical constituents (oxidation-reduction potential, nitrate, ammonium, and phosphate) along interpreted flow paths which is partly consistent with hyporheic exchange. The variability and heterogeneity of reducing and oxidizing conditions is interpreted to be a result of groundwater-surface water interaction. Two-dimensional mapping of biogeochemical parameters show redox transitions along interpreted flow paths. Further analysis of various measured unstable chemical parameters results in observable trends strongly delineated along these preferential flow paths that are consistent with the direction of groundwater flow and the assumed

  11. The life of a meander bend: Connecting shape and dynamics via analysis of a numerical model

    NASA Astrophysics Data System (ADS)

    Schwenk, Jon; Lanzoni, Stefano; Foufoula-Georgiou, Efi

    2015-04-01

    Analysis of bend-scale meandering river dynamics is a problem of theoretical and practical interest. This work introduces a method for extracting and analyzing the history of individual meander bends from inception until cutoff (called "atoms") by tracking backward through time the set of two cutoff nodes in numerical meander migration models. Application of this method to a simplified yet physically based model provides access to previously unavailable bend-scale meander dynamics over long times and at high temporal resolutions. We find that before cutoffs, the intrinsic model dynamics invariably simulate a prototypical cutoff atom shape we dub simple. Once perturbations from cutoffs occur, two other archetypal cutoff planform shapes emerge called long and round that are distinguished by a stretching along their long and perpendicular axes, respectively. Three measures of meander migration—growth rate, average migration rate, and centroid migration rate—are introduced to capture the dynamic lives of individual bends and reveal that similar cutoff atom geometries share similar dynamic histories. Specifically, through the lens of the three shape types, simples are seen to have the highest growth and average migration rates, followed by rounds, and finally longs. Using the maximum average migration rate as a metric describing an atom's dynamic past, we show a strong connection between it and two metrics of cutoff geometry. This result suggests both that early formative dynamics may be inferred from static cutoff planforms and that there exists a critical period early in a meander bend's life when its dynamic trajectory is most sensitive to cutoff perturbations. An example of how these results could be applied to Mississippi River oxbow lakes with unknown historic dynamics is shown. The results characterize the underlying model and provide a framework for comparisons against more complex models and observed dynamics.

  12. Computer simulations of channel meandering and the formation of point bars: Linking channel dynamics to the preserved stratigraphy

    NASA Astrophysics Data System (ADS)

    Sun, T.; Covault, J. A.; Pyrcz, M.; Sullivan, M.

    2012-12-01

    Meandering rivers are probably one of the most recognizable geomorphic features on earth. As they meander across alluvial and delta plains, channels migrate laterally and develop point bars, splays, levees and other geomorphic and sedimentary features that compose substantial portions of the fill within many sedimentary basins. These basins can include hydrocarbon producing fields. Therefore, a good understanding of the processes of meandering channels and their associated deposits is critical for exploiting these reservoirs in the subsurface. In the past couple of decades, significant progress has been made in our understanding of the morphodynamics of channel meandering. Basic fluid dynamics and sediment transport (Ikeda and Parker, 1981; Howard, 1992) has shown that many characteristic features of meandering rivers, such as the meandering wavelength, growth rate and downstream migration rate, can be predicted quantitatively. As a result, a number of variations and improvement of the theory have emerged (e.g., Blondeaux and Seminara, 1985; Parker and Andrews, 1985, 1986; and Sun et al., 2001a, b).The main improvements include the recognition of so called "bar-bend" interactions, where the development of bars on the channel bed and their interactions with the channel bend is recognized as a primary cause for meandering channels to develop greater complexity than the classic goose-neck meander bend shapes, such as compound bend. Recently, Sun and others have shown that the spatial patterns of width variations in meandering channels can be explained by an extrinsic periodic flow variations coupled with the intrinsic bend instability dynamics. In contrast to the significant improvement of our understanding of channel meandering, little work has been done to link the geomorphic features of meandering channels to the geometry and heterogeneity of the deposits they form and ultimately preserves. A computer simulation model based on the work of Sun and others (1996, 2001

  13. A simple algorithm for the mapping of TIN data onto a static grid: Applied to the stratigraphic simulation of river meander deposits

    NASA Astrophysics Data System (ADS)

    Clevis, Quintijn; Tucker, Gregory E.; Lancaster, Stephen T.; Desitter, Arnaud; Gasparini, Nicole; Lock, Gary

    2006-07-01

    Triangulated irregular networks (TIN) in landscape evolution models have the advantage of representing geologic processes that involve a horizontal component, such as faulting and river meandering, due to their adaptive remeshing capability of moving, adding and deleting nodes. However, the moving node feature is difficult to integrate with the accumulation of a three-dimensional (3D) subsurface stratigraphy, because it requires 3D subsurface interpolation, which results in stratigraphic data loss due to heterogeneity of the subsurface and averaging effects. We present a simple algorithm that maps any changes in the configuration of TIN landscape nodes onto a static grid, facilitating the creation of a fixed stratigraphic record of TIN surface change. The algorithm provides a practical solution not only for the stratigraphic problem, but also for other problems that involve linking of models that use TIN and raster discretization schemes. An example application is presented using the river meandering module incorporated in the CHILD landscape evolution model. Examples are shown of cross-sections, and voxel distributions and geo-archaeological depth-age maps. These illustrate the type of insights that can be obtained from process-based modeling of subsurface fluvial architecture, and highlight potential applications of stratigraphic simulation.

  14. Analysing the meandering rivers responses to the slope-changes, depending on their bankfull discharge - Case study in the Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Petrovszki, Judit; Timár, Gábor; Molnár, Gábor

    2014-05-01

    The multi-variable connection between the channel slope, bankfull discharge and sinuosity values were analysed to get a mathematical formula, which describes the responses of the rivers, and gives the probable sinuosity values for every slope and discharge values. Timár (2003) merged two planar diagrams into a quasi 3D graph. One of them displayed how the river pattern changes, according to the slope and bankfull discharge values (Leopold and Wolmann, 1957; Ackers and Charlton, 1971); the other based on flume experiments, and gives a connection between the slope and sinuosity (Schumm and Khan, 1972). The result graph suggests that the slope-sinuosity connection also works along the natural rivers, for every discharge values. The aim of this work was to prove this relation, and describe it numerically. The sinuosity values were calculated along the natural, meandering river beds, using historical maps (2nd Military Survey of the Habsburg Empire, from the 19th century). The available slope and discharge values were imported from a database measured after the main river control works, at the beginning of the 20th century (Viczián, 1905). Analysing the reports of the river control works, the natural slope could be computed for every river sections. The mean discharges were also converted to bankfull discharges. Neither long time series, nor cross sectional areas were obtainable, so other method was used to generate the bankfull discharge. After the above mentioned corrections a quadratic polynomial surface was fitted onto these points with least squares regression. The cross section of this surface follows the theoretical slope-sinuosity graph, verifying that the flume experiments and natural rivers behave similarly. The differences between the fitted surface and the original points were caused by other river parameters, which also affect the natural rivers (e.g. the sediment discharge). Furthermore, this graph confirms the connection between the slope and sinuosity

  15. Meandering: fluvial versus tidal. (Invited)

    NASA Astrophysics Data System (ADS)

    Seminara, G.

    2009-12-01

    the channel, whereas the seaward pattern displayed deposition at the outer bends and scour at the inner bends, a pattern which would clearly be planimetrically unstable if the channel walls were erodible. In a second experiment, in the final stage, close to equilibrium, point bars were out of phase with respect to curvature throughout the whole channel. A possible explanation of this striking observation is that asymmetry of an observed pattern must be associated with either flood- or ebb- dominance of the basic flow field: some indication, in this respect, comes from the observation that the bar-pool pattern changed in time with the hydrodynamics as the average bed profile evolved towards equilibrium. A second key to be explored is the very nature of the observed bar-pool pattern, recalling that the relationship of tidal alternate (free) bars to point (forced) bars differs from its fluvial counterpart: tidal free bars are non migrating features at equilibrium (Seminara and Tubino, J Fluid Mech, 2001), bar migration arising from the role of overtides (Garotta et al, Phys. of Fluids, 2006). Distinguishing free from forced bars is then harder than in the fluvial case and the issue of their possible coexistence needs be revisited. Finally, the plan form evolution of tidal meanders is typically slower than in the fluvial case: not surprisingly, as sediment transport is very weak close to channel equilibrium.

  16. River Channel Migration: A Remote Sensing and GIS Analysis

    NASA Astrophysics Data System (ADS)

    Islam, Tariqul

    2010-12-01

    Remote sensing and geographic information system provide tools for quantitative and qualitative river morphological analysis. Bangladesh is a riverine, flood prone country and, the Padma and the Jamuna are two of major three rivers in the country. The aim of this research is to monitor the channel migration of the Padma and the Jamuna rivers since 1977 to 2004 using remote sensing and GIS. Four scenes for dry season's cloud free Landsat images were used in this study. Images were processed using PCI Geomatica and ArcGIS 9.3 was used for GIS analysis. The Landsat images were visualized and identified nine locations to investigate the channel migration. The images were classified into two broad categories, i.e. water and nonwater body. ArcGIS 9.3 was used to transfer these classified images into GIS layers. A standard measurement tool of ArcGIS was applied to measure the movement of river channel based on initial river channel in 1977. General trend of the Padma and the Jamuna river channel migration at locations A, B, C, D, F, G, H and I towards north, northeast and southwest eventually, north, northeast, east, east, west and west, respectively. The confluence point of the Padma and Jamuna (at location E) migrated toward southeast with high rate. During 1977-2004, it migrated about 9000m toward southeast. Trend of migration of the confluence point was faster than any other locations in the channel of the Padma river.

  17. River response to climate and sea level changes during the Late Saalian/Early Eemian in northern Poland - a case study of meandering river deposits in the Chłapowo cliff section

    NASA Astrophysics Data System (ADS)

    Moskalewicz, Damian; Sokołowski, Robert J.; Fedorowicz, Stanisław

    2016-03-01

    Fluvial sediments in the Chłapowo cliff section were studied in order to reconstruct their palaeoflow conditions and stratigraphical position. Lithofacies, textural and palaeohydraulic analyses as well as luminescence dating were performed so as to achieve the aim of study. Sedimentary successions were identified as a record of point bar cycles. The fluvial environment probably functioned during the latest Saalian, shortly after the retreat of the Scandinavian Ice Sheet. Discharge outflow was directed to the northwest. The river used the older fluvioglacial valley and probably was directly connected to the Eem Sea. Good preservation and strong aggradation of point-bar cycles were related to a rapid relative base level rise. The meandering river sediments recognised showed responses to climate and sea level changes as illustrated by stratigraphical, morphological and sedimentological features of the strata described. The present study also revealed several insights into proper interpretation of meandering fluvial successions, in which the most important were: specific lithofacies assemblage of GSt (St, Sp) → Sl → SFrc → Fm (SFr) and related architectural elements: channel/sandy bedforms CH/SB → lateral accretion deposits LA → floodplain fines with crevasse splays FF (CS); upward-fining grain size and decreasing content of denser heavy minerals; estimated low-energy flow regime with a mean depth of 1.6-3.3 m, a Froude number of 0.2-0.4 and a sinuosity of 1.5.

  18. Spatial patterns of groundwater-surface water interactions at the meander-bend scale in a gravel-bed lowland river during a large-scale flow experiment

    NASA Astrophysics Data System (ADS)

    Bray, E. N.; Dunne, T.

    2012-12-01

    Improved characterization of 1) streambed hydraulic conductivity and 2) near-bed and subsurface water temperatures allows better understanding of the spatial patterns of groundwater-surface water exchange in rivers. We measured the effects of a large-scale flow experiment on groundwater-surface water exchange and temperature using fiber optic distributed temperature sensing (DTS), measured temperature in the shallow hyporheic zone (46 cm), and measured streambed saturated hydraulic conductivity (Ksat) over the length of three river meander bends (2 km). Measured channel bed elevation, flow depth, velocity, and bed-material grain size were used to develop a two-dimensional numerical model of the flow field as boundary conditions for a model of the hyporheic flow field. We deployed 2 km of fiber-optic cable directly on top of the riverbed over three pool-riffle sequences each with a different degree of bed mobility. DTS data were collected every 2 m for 32 days (1.5 days at 10 cms, 10 days at 20 cms, 16 days at 10 cms, and 4.5 days at 2-4 cms). Three installations of six hyporheic zone sensors, located near the upstream and downstream ends of the DTS cable, recorded interstitial pore water temperature at depths of 46 cm. During flows of 10 cms, we measured Ksat in the streambed at depths of 60 cm using a groundwater standpipe and backpack permeameter over the length of two meander bends. DTS results showed relatively uniform temperature over the 2-km reach during the initial flow of 10 cms. Near-bed temperatures averaged 15.6°C while pore water temperatures averaged 15.4°C. The 20 cms flow decreased near-bed temperatures to 14.9°C and pore water temperatures averaged 14.7°C. However, during the 20 cms flow, the bed became mobile causing local scour and deposition at three locations and buried the DTS cable with gravel/sand up to 26 cm deep. Our DTS results allowed us to record the transition from near-bed temperatures to shallow subsurface temperatures during a

  19. 2D and 3D numerical simulations of morphodynamics structures in a large-amplitude meanders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the pioneering study of the Ishikari River, Japan, Kinoshita (Kinoshita 1957, 1961) described two types of meandering channels: (1) channel with two bars per meander wavelength (one bar per bend), and (2) channel with three or more bars per meander wavelength (multiple bars per bend). Based on th...

  20. Spatiotemporal Dynamics of River Channel Migration on the Ganges-Brahmaputra Delta: 2000-2013

    NASA Astrophysics Data System (ADS)

    Small, C.; Chiu, S.; Sousa, D.; Mondal, D. R.; Steckler, M. S.; Akhter, S. H.; Mia, B.; Goodbred, S. L., Jr.; Wilson, C.; Seeber, L.

    2014-12-01

    downstream migration of the larger meanders on both rivers. We also observe a pronounced change in the morphology and evolution of the channels in the Brahmaputra braid plain upstream and downstream of the hinge zone with more rapid changes in channel geometry upstream and a more stable configuration of two anastamosing primary channels downstream.

  1. Optimum swimming pathways of fish spawning migrations in rivers.

    PubMed

    McElroy, Brandon; DeLonay, Aaron; Jacobson, Robert

    2012-01-01

    Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this and similar hypotheses. First, a cost function is derived for upstream migration that relates work done by a fish to swimming drag. The energetic cost scales with the cube of a fish's relative velocity integrated along its path. By normalizing to the energy requirements of holding a position in the slowest waters at the path's origin, a cost function is derived that depends only on the physical environment and not on specifics of individual fish. Then, as an example, we demonstrate the analysis of a migration pathway of a telemetrically tracked pallid sturgeon (Scaphirhynchus albus) in the Missouri River (USA). The actual pathway cost is lower than 10(5) random paths through the surveyed reach and is consistent with the optimization hypothesis. The implication--subject to more extensive validation--is that reproductive success in managed rivers could be increased through manipulation of reservoir releases or channel morphology to increase abundance of lower-cost migration pathways. PMID:22486084

  2. Optimum swimming pathways of fish spawning migrations in rivers

    USGS Publications Warehouse

    McElroy, Brandon; DeLonay, Aaron; Jacobson, Robert

    2012-01-01

    Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this and similar hypotheses. First, a cost function is derived for upstream migration that relates work done by a fish to swimming drag. The energetic cost scales with the cube of a fish's relative velocity integrated along its path. By normalizing to the energy requirements of holding a position in the slowest waters at the path's origin, a cost function is derived that depends only on the physical environment and not on specifics of individual fish. Then, as an example, we demonstrate the analysis of a migration pathway of a telemetrically tracked pallid sturgeon (Scaphirhynchus albus) in the Missouri River (USA). The actual pathway cost is lower than 105 random paths through the surveyed reach and is consistent with the optimization hypothesis. The implication—subject to more extensive validation—is that reproductive success in managed rivers could be increased through manipulation of reservoir releases or channel morphology to increase abundance of lower-cost migration pathways.

  3. Optimum Pathways of Fish Spawning Migrations in Rivers

    NASA Astrophysics Data System (ADS)

    McElroy, B. J.; Jacobson, R. B.; Delonay, A.

    2010-12-01

    Many fish species migrate large distances upstream in rivers to spawn. These migrations require energetic expenditures that are inversely related to fecundity of spawners. Here we present the theory necessary to quantify relative energetic requirements of upstream migration pathways and then test the hypothesis that least-cost paths are taken by the federally endangered pallid sturgeon (Scaphyrhyncus Albus), a benthic rheophile, in the lower Missouri River, USA. Total work done by a fish through a migratory path is proportional to the size of the fish, the total drag on the fish, and the distance traversed. Normalizing by the work required to remain stationary at the beginning of a path, relative work expenditure at each point of the path is found to be the cube of the ratio of the velocity along the path to the velocity at the start of the path. This is the velocity of the fish relative to the river flow. A least-cost migratory pathway can be determined from the velocity field in a reach as the path that minimizes a fish's relative work expenditure. We combine location data from pallid sturgeon implanted with telemetric tags and pressure-sensitive data storage tags with depth and velocity data collected with an acoustic Doppler profiler. During spring 2010 individual sturgeon were closely followed as they migrated up the Missouri River to spawn. These show that, within a small margin, pallid sturgeon in the lower Missouri River select least-cost paths as they swim upstream (typical velocities near 1.0 - 1.2 m/s). Within the range of collected data, it is also seen that many alternative paths not selected for migration are two orders of magnitude more energetically expensive (typical velocities near 2.0 - 2.5 m/s). In general these sturgeon migrated along the inner banks of bends avoiding high velocities in the thalweg, crossing the channel where the thalweg crosses in the opposite direction in order to proceed up the inner bank of subsequent bends. Overall, these

  4. Testing river surveying techniques in tidal environments: example from an actively meandering channel surveyed with TLS (Mont Saint-Michel bay, France)

    NASA Astrophysics Data System (ADS)

    Leroux, J.; Lague, D.

    2013-12-01

    factor 2 during summer/autumn spring tides at the peak of pioneer vegetation development. Bank erosion and channel dynamics show a marked difference for tides reaching the salt marsh elevation. For tides below marsh elevation, bank erosion is negligible and the channel is systematically aggrading at a rate proportional to HWL. For tides flooding the marsh, mean bank erosion increases linearly with HWL and the channel shifts to erosion for over-marsh tides. Using flow velocity and SSC data we show that sedimentation on the inner bar results from the penetration of the turbid flood onto the inner bar. Spatial variability in sedimentation results from local interactions between flow and vegetation. On the contrary, bank erosion is dominated by the very large ebb peak velocity developing during spring tides. The very non-linear sensitivity to HWL of bank erosion and channel erosion means that the rate of evolution is largely controlled by the largest tides of the year. This in turn yields very large annual fluctuations in the rates of meander evolution. These results demonstrate that mega-tidal environment can offer an alternative setting to test new survey techniques aimed at river monitoring and can shed light in the elementary processes governing biogeomorphological interactions.

  5. [Ethnic dimension to migration in the Senegal river valley].

    PubMed

    Traore, S

    1993-08-01

    Studies of the factors determining migratory patterns in the Senegal River Valley usually stress the importance of economic factors related to colonial domination. But when cultural factors and the social relations governing them are examined in a comparative study of ethnic groups, distinct population subgroups may be revealed to have differential migratory patterns. The Soninka and the Poular, two groups highly affected by migration, were chosen for an analysis of the impact of specific historical experiences on migratory behavior. A historical analysis of colonial archives and anthropological and historical monographs and the 1982-83 "Survey of Migration in the Valley of the Senegal River" provided data. The survey indicated that Soninka and Poular migratory patterns differed from each other, but that both differed from the migratory patterns of all other ethnic groups in the region. Soninka migration is international and oriented primarily toward Europe. It has recently become more intense than that of the poular. The determinants of migration in the two groups appear related more to the structure of households than to lack of educational and health facilities or even of food at the village level. Pastoral life and its associated beliefs and religious ideology appear to have been the principal determinants of precolonial movement among the Poular, while Soninka migration responded more to competition over control of manpower. Itinerant commercial activity was coupled with use of slave labor to ensure food production. But the suppression of slavery and crises of subsistence aggravated by colonial policy provoked ever more distant migration, which found a focus in the French demand for labor after World War II. Migration as an alternative does not appear to have been as significant for the Poular until more recently, when subsistence agriculture and the sale of animals were no longer sufficient to cover monetary needs. Male migration among the Soninka is a

  6. Potamodromous migrations in the Magdalena River basin: bimodal reproductive patterns in neotropical rivers.

    PubMed

    López-Casas, S; Jiménez-Segura, L F; Agostinho, A A; Pérez, C M

    2016-07-01

    Magdalena River basin potamodromous fishes have two annual reproductive seasons: the subienda in the first half of the year and the mitaca in the second. Both upstream migrations are c. 30-45 days long; after that, with the onset of the rainy season, fishes spawn and remain in the river (resident individuals) or start a downstream movement (the bajanza) to return to the Magdalena floodplain lakes (nursery, shelter and feeding grounds). Due to their particular gonad development the bocachico Prochilodus magdalenae and probably the comelón Leporinus muyscorum are physiologically able to undertake two annual basin migrations. In the presence of dams or hydropower structures, fishes are able to find alternative migration routes. Some species should be re-classified in their migratory behaviour.

  7. Potamodromous migrations in the Magdalena River basin: bimodal reproductive patterns in neotropical rivers.

    PubMed

    López-Casas, S; Jiménez-Segura, L F; Agostinho, A A; Pérez, C M

    2016-07-01

    Magdalena River basin potamodromous fishes have two annual reproductive seasons: the subienda in the first half of the year and the mitaca in the second. Both upstream migrations are c. 30-45 days long; after that, with the onset of the rainy season, fishes spawn and remain in the river (resident individuals) or start a downstream movement (the bajanza) to return to the Magdalena floodplain lakes (nursery, shelter and feeding grounds). Due to their particular gonad development the bocachico Prochilodus magdalenae and probably the comelón Leporinus muyscorum are physiologically able to undertake two annual basin migrations. In the presence of dams or hydropower structures, fishes are able to find alternative migration routes. Some species should be re-classified in their migratory behaviour. PMID:27073186

  8. Meandering Brownian Donkeys

    NASA Astrophysics Data System (ADS)

    Eichhorn, R.; Reimann, P.

    2004-04-01

    We consider a Brownian particle whose motion is confined to a ``meandering'' pathway and which is driven away from thermal equilibrium by an alternating external force. This system exhibits absolute negative mobility, i.e. when an external static force is applied the particle moves in the direction opposite to that force. We reveal the physical mechanism behind this ``donkey-like'' behavior, and derive analytical approximations that are in excellent agreement with numerical results.

  9. Downstream-migrating fluvial point bars in the rock record

    NASA Astrophysics Data System (ADS)

    Ghinassi, Massimiliano; Ielpi, Alessandro; Aldinucci, Mauro; Fustic, Milovan

    2016-04-01

    Classical models developed for ancient fluvial point bars are based on the assumption that meander bends invariably increase their radius as meander-bend apices migrate in a direction transverse to the channel-belt axis (i.e., meander bend expansion). However, many modern meandering rivers are also characterized by down-valley migration of the bend apex, a mechanism that takes place without a significant change in meander radius and wavelength. Downstream-migrating fluvial point bars (DMFPB) are the dominant architectural element of these types of meander belts. Yet they are poorly known from ancient fluvial-channel belts, since their disambiguation from expansional point bars often requires fully-3D perspectives. This study aims to review DMFPB deposits spanning in age from Devonian to Holocene, and to discuss their main architectural and sedimentological features from published outcrop, borehole and 3D-seismic datasets. Fluvial successions hosting DMFPB mainly accumulated in low accommodation conditions, where channel belts were affected by different degrees of morphological (e.g., valleys) or tectonic (e.g., axial drainage of shortening basins) confinement. In confined settings, bends migrate downstream along the erosion-resistant valley flanks and little or no floodplain deposits are preserved. Progressive floor aggradation (e.g., valley filling) allow meander belts with DMFPB to decrease their degree of confinement. In less confined settings, meander bends migrate downstream mainly after impinging against older, erosion-resistant channel fill mud. By contrast, tectonic confinement is commonly associated with uplifted alluvial plains that prevented meander-bend expansion, in turn triggering downstream translation. At the scale of individual point bars, translational morphodynamics promote the preservation of downstream-bar deposits, whereas the coarser-grained upstream and central beds are less frequently preserved. However, enhanced preservation of upstream

  10. Were Rivers Flowing across the Sahara During the Last Interglacial? Implications for Human Migration through Africa

    PubMed Central

    Coulthard, Tom J.; Ramirez, Jorge A.; Barton, Nick; Rogerson, Mike; Brücher, Tim

    2013-01-01

    Human migration north through Africa is contentious. This paper uses a novel palaeohydrological and hydraulic modelling approach to test the hypothesis that under wetter climates c.100,000 years ago major river systems ran north across the Sahara to the Mediterranean, creating viable migration routes. We confirm that three of these now buried palaeo river systems could have been active at the key time of human migration across the Sahara. Unexpectedly, it is the most western of these three rivers, the Irharhar river, that represents the most likely route for human migration. The Irharhar river flows directly south to north, uniquely linking the mountain areas experiencing monsoon climates at these times to temperate Mediterranean environments where food and resources would have been abundant. The findings have major implications for our understanding of how humans migrated north through Africa, for the first time providing a quantitative perspective on the probabilities that these routes were viable for human habitation at these times. PMID:24040347

  11. Water surface and channel bed morphology change before and after a laboratory meander neck cutoff

    NASA Astrophysics Data System (ADS)

    Han, B.; Endreny, T. A.

    2012-12-01

    Meander evolution of narrowing point bars ultimately forms a straight reach and an associated oxbow lake after meand bend cutoff. Observing the water surface and bed topography change during the meander cutoff process allows scientists and engineers to better understand flow mechanisms in meandering rivers, predict river behavior following cutoff, and minimize damage to life and property. Theoretical river evolution model indicates that head loss between the upstream and downstream meander neck increases during meander evolution, and this leads to an increasing hydraulic gradient and intensification of the cutoff. Yet no detailed observations are available to support the theory. In this research, we establish a physical model of a meander cutoff in a 1.8 m * 3.7 m laboratory river table using 0.18 mm median diameter sand and river discharge of 100 mL/s. The initial meander is a highly curved meander with a sinuosity of 5.6. Erosion is initiated by stream flow and the meander goes through the cutoff process. Water surface elevation along the river, river bed topography, and groundwater head in the intra-meander zone are precisely measured with an accuracy of up to 0.4 mm using a close range photogrammetry technique and ultrasonic sensors. The measurements are taken every 5 hours before the cutoff, immediately after the cutoff, and 1 hour, 5 hours after the cutoff respectively. Our results show that hydraulic gradient gradually steepens crossing the meander neck before the cutoff. River bed elevation gradients crossing the meander neck are enlarged due to the continuous deposition at the upstream neck and erosion at the downstream neck. However, the river bed elevation differences is counter balanced by the water depth which is smaller at the upstream and larger at the downstream, and the head loss across the neck remains nearly the same during cutoff. Immediately after the meander cutoff, a cascade emerges, and then rapidly dissipates into the new channel during

  12. Migration of the Ganga River and development of cliffs in the Varanasi region, India during the late Quaternary: Role of active tectonics

    NASA Astrophysics Data System (ADS)

    Shukla, U. K.; Srivastava, P.; Singh, I. B.

    2012-10-01

    The lithofacies constitution of unconsolidated sediments exposed in Ramnagar cliff indicates sedimentation in sinuous channels, associated flood plain areas and ponds that were developed within the Ganga River valley. The Khadar surface represents a raised river valley terrace into which the main river channel along with its narrow floodplain is incised. Ramnagar cliff section has revealed a variety of deformation structures that indicate repeated tectonic activity in the area. Important tectonic features exposed by the cliff section are reverse faults, folds, cracks filled with sparry calcite and soft sediment structures indicating liquefaction of sediments affected by faulting and folding. Optically stimulated luminescence (OSL) dating of sediments and field relationships of tectonic elements indicate that the Ganga River migrated near to Varanasi 40 ka following a tectonic event in the area. Since then, it meandered freely within its valley until 7 ka when another tectonic event took place and Ramnagar cliff was raised to its present heights. The cliff surface was degraded by gulling activity for about 4000 years before it was occupied by man at around 3000 years BP.

  13. Sediment supply as a driver of river evolution in the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Ahmed, Joshua; Constantine, José Antonio; Dunne, Thomas; Legleiter, Carl; Lazarus, Eli D.

    2015-04-01

    The Amazon represents the only large river basin in the world where there is a sufficient range of sediment supplies and a lack of engineering controls to assess how sediment supply drives the evolution of meandering rivers. Despite recent analytical advances (Asahi et al., 2013; Pittaluga and Seminara, 2011), modern theory does not yet identify or explain the effects of externally imposed sediment supplies, a fundamental river characteristic, on meandering river evolution. These sediment supplies would be radically reduced by the construction of large dams proposed for the Amazon Basin (Finer and Jenkins, 2012). Here, we demonstrate that the sediment loads imposed by their respective drainage basins determine planform changes in lowland rivers across the Amazon. Our analysis, based on Landsat image sequences, indicates that rivers with high sediment loads draining the Andes and associated foreland basin experience annual migration rates that are on average four times faster than rivers with lower sediment loads draining the Central Amazon Trough and shields. Incidents of meander cutoff also occur more frequently along the rivers of the Andes and foreland basin, where the number of oxbows in the floodplains is more than twice that observed in the floodplains of the Central Amazon Trough and shields. Our results, which cannot be explained by differences in channel slope or hydrology, highlight the importance of sediment supply in modulating the ability of meandering alluvial rivers to reshape the floodplain environment through river migration. Asahi, K., Shimizu, Y., Nelson, J., Parker, G., 2013. Numerical simulation of river meandering with self-evolving banks. Journal of Geophysical Research: Earth Surface, 118(4), 2013JF002752. Finer, M., Jenkins, C.N., 2012. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity. PLOS One, 7(4), e35126. Pittaluga, M.B., Seminara, G., 2011. Nonlinearity and unsteadiness in river

  14. Meander in valley crossing a deep-ocean fan.

    PubMed

    Shepard, F P

    1966-10-21

    Seaward of most submarine canyons there are large sediment fans comparable to the fans at the base of mountain ranges. Many of the submarine fans are cut by valleys called fan-valleys which usually connect with the mouths of submarine canyons. Loop-like bends or meanders characterize the channels of rivers in their lower flood plains, but have never been found in the shallow channels that cross the alluvial fans at the base of mountain canyons. Therefore, it was surprising to find that the channel in a very deep submarine fan-valley off Monterey Bay, California, has a tight meander. PMID:17751705

  15. Meander in valley crossing a deep-ocean fan.

    PubMed

    Shepard, F P

    1966-10-21

    Seaward of most submarine canyons there are large sediment fans comparable to the fans at the base of mountain ranges. Many of the submarine fans are cut by valleys called fan-valleys which usually connect with the mouths of submarine canyons. Loop-like bends or meanders characterize the channels of rivers in their lower flood plains, but have never been found in the shallow channels that cross the alluvial fans at the base of mountain canyons. Therefore, it was surprising to find that the channel in a very deep submarine fan-valley off Monterey Bay, California, has a tight meander.

  16. Spatio-Temporal Migration Patterns of Pacific Salmon Smolts in Rivers and Coastal Marine Waters

    PubMed Central

    Melnychuk, Michael C.; Welch, David W.; Walters, Carl J.

    2010-01-01

    Background Migrations allow animals to find food resources, rearing habitats, or mates, but often impose considerable predation risk. Several behavioural strategies may reduce this risk, including faster travel speed and taking routes with shorter total distance. Descriptions of the natural range of variation in migration strategies among individuals and populations is necessary before the ecological consequences of such variation can be established. Methodology/Principal Findings Movements of tagged juvenile coho, steelhead, sockeye, and Chinook salmon were quantified using a large-scale acoustic tracking array in southern British Columbia, Canada. Smolts from 13 watersheds (49 watershed/species/year combinations) were tagged between 2004–2008 and combined into a mixed-effects model analysis of travel speed. During the downstream migration, steelhead were slower on average than other species, possibly related to freshwater residualization. During the migration through the Strait of Georgia, coho were slower than steelhead and sockeye, likely related to some degree of inshore summer residency. Hatchery-reared smolts were slower than wild smolts during the downstream migration, but after ocean entry, average speeds were similar. In small rivers, downstream travel speed increased with body length, but in the larger Fraser River and during the coastal migration, average speed was independent of body length. Smolts leaving rivers located towards the northern end of the Strait of Georgia ecosystem migrated strictly northwards after ocean entry, but those from rivers towards the southern end displayed split-route migration patterns within populations, with some moving southward. Conclusions/Significance Our results reveal a tremendous diversity of behavioural migration strategies used by juvenile salmon, across species, rearing histories, and habitats, as well as within individual populations. During the downstream migration, factors that had strong effects on travel

  17. Relationship Between Vortex Meander and Ambient Turbulence

    NASA Technical Reports Server (NTRS)

    Rossow, Vernon J.; Hardy, Gordon H.; Meyn, Larry A.

    2006-01-01

    Efforts are currently underway to increase the capacity of airports by use of closely-spaced parallel runways. If such an objective is to be achieved safely and efficiently during both visual and instrument flight conditions, it will be necessary to develop more precise methods for the prediction of the motion and spread of the hazard posed by the lift-generated vortex-wakes of aircraft, and their uncertainties. The purpose of the present study is to relate the motion induced in vortex filaments by turbulence in the ambient flow field to the measured turbulence in the flow field. The problem came about when observations made in the two largest NASA wind tunnels indicated that extended exposure of vortex wakes to the turbulence in the wind tunnel air stream causes the centers of the vortices to meander about with time at a given downstream station where wake measurements are being made. Although such a behavior was expected, the turbulence level based on the maximum amplitude of meander was much less than the root-mean-squared value measured in the free-stream of the wind tunnel by use of hot-film anemometers. An analysis of the time-dependent motion of segments of vortex filaments as they interact with an eddy, indicates that the inertia of the filaments retards their motion enough in the early part of their travel to account for a large part of the difference in the two determinations of turbulence level. Migration of vortex filaments from one turbulent eddy to another (probably with a different orientation), is believed to account for the remainder of the difference. Methods that may possibly be developed for use in the measurement of the magnitude of the more intense eddies in turbulent flow fields and how they should be adjusted to predict vortex meander are then discussed.

  18. Late Pleistocene river migrations in response to thrust belt advance and sediment-flux steering - The Kura River (southern Caucasus)

    NASA Astrophysics Data System (ADS)

    von Suchodoletz, Hans; Gärtner, Andreas; Hoth, Silvan; Umlauft, Josefine; Sukhishvili, Lasha; Faust, Dominik

    2016-08-01

    One reaction of rivers toward allogenic triggers is the large-scale river channel migration in the form of avulsions or progressive lateral migrations (combing) that are widespread phenomena around the world during the late Quaternary. Because they potentially cause significant human and economic losses and significantly change geomorphic processes in the affected regions, a deeper knowledge about causes and rates is essential and furthermore helps to identify the dominant drivers of regional landscape evolution during different periods. One possible cause for river channel migrations is sediment-flux steering, i.e. the shift of rivers in sedimentary basins against a tectonically driven trend caused by transverse sediment discharge. During the last 30 years, sediment-flux steering has been investigated by field and experimental studies in extensional half-grabens with generally small-sized transverse catchments and/or volcaniclastic sedimentation. This study presents geomorphologic, geochronologic, and heavy mineral analyses together with complementary tectonomorphometric and earthquake data to investigate late Quaternary channel migrations of the Kura River in the southern foreland basin of the Greater Caucasus, a region where the late Quaternary landscape evolution is rather fragmentarily understood so far. Special emphasis of this study is given to the interplay between axial river flow and transverse sediment supply leading to sediment-flux steering. Large-scale migrations of the course of the Kura River during the late Quaternary reflect the interplay between tectonic processes leading to the southwestward advance of the Kura Fold-and-Thrust-Belt and climatically-triggered sediment-flux steering caused by aggradation phases of transverse rivers with comparatively large catchment areas in the Lesser Caucasus. During generally warmer periods such as the Holocene with fluvial incision and low sediment supply from the transverse rivers, the main Kura River could

  19. Flow structure and channel morphology at a natural confluent meander bend

    NASA Astrophysics Data System (ADS)

    Riley, James D.; Rhoads, Bruce L.

    2012-08-01

    Previous experimental, field, and modeling studies of confluence dynamics have focused mainly on junctions formed by straight channels. In contrast, natural rivers often meander and tributaries can enter meandering rivers on the outside of bends to form a junction planform known as a confluent meander bend. In this study, field measurements of three-dimensional velocity components and bed topography at a confluent meander bend reveal a complex hydrodynamic environment that responds to changes in momentum-flux ratio, while channel morphology remains relatively stable. Flow from the tributary deflects high-velocity flow and helical motion in the curving main river toward the inside of the bend, inducing bed scour and inhibiting point-bar development. The high junction angle forces the tributary flow to abruptly realign to the orientation of the downstream channel, initiating a counter-rotating helical cell over the outer portion of the bend. Two surface-convergent helical cells persist through the downstream channel, where the combined flows accelerate as the channel cross-sectional area is constricted by a bar along the downstream junction corner, precluding flow separation. Long-term stability of its planform suggests that this confluent meander bend represents a quasi-stable channel configuration. Overall, patterns of flow and channel morphology are quite different from typical patterns in most meander bends, but are generally consistent with a conceptual model of confluent meander bends derived from previous laboratory experiments and numerical modeling.

  20. Survival of migrating salmon smolts in large rivers with and without dams.

    PubMed

    Welch, David W; Rechisky, Erin L; Melnychuk, Michael C; Porter, Aswea D; Walters, Carl J; Clements, Shaun; Clemens, Benjamin J; McKinley, R Scott; Schreck, Carl

    2008-10-28

    The mortality of salmon smolts during their migration out of freshwater and into the ocean has been difficult to measure. In the Columbia River, which has an extensive network of hydroelectric dams, the decline in abundance of adult salmon returning from the ocean since the late 1970s has been ascribed in large measure to the presence of the dams, although the completion of the hydropower system occurred at the same time as large-scale shifts in ocean climate, as measured by climate indices such as the Pacific Decadal Oscillation. We measured the survival of salmon smolts during their migration to sea using elements of the large-scale acoustic telemetry system, the Pacific Ocean Shelf Tracking (POST) array. Survival measurements using acoustic tags were comparable to those obtained independently using the Passive Integrated Transponder (PIT) tag system, which is operational at Columbia and Snake River dams. Because the technology underlying the POST array works in both freshwater and the ocean, it is therefore possible to extend the measurement of survival to large rivers lacking dams, such as the Fraser, and to also extend the measurement of survival to the lower Columbia River and estuary, where there are no dams. Of particular note, survival during the downstream migration of at least some endangered Columbia and Snake River Chinook and steelhead stocks appears to be as high or higher than that of the same species migrating out of the Fraser River in Canada, which lacks dams. Equally surprising, smolt survival during migration through the hydrosystem, when scaled by either the time or distance migrated, is higher than in the lower Columbia River and estuary where dams are absent. Our results raise important questions regarding the factors that are preventing the recovery of salmon stocks in the Columbia and the future health of stocks in the Fraser River.

  1. Out of Africa: the importance of rivers as human migration corridors

    NASA Astrophysics Data System (ADS)

    Ramirez, J. A.; Coulthard, T. J.; Rogerson, M.; Barton, N.; Bruecher, T.

    2013-12-01

    The route and timing of Homo sapiens exiting Africa remains uncertain. Corridors leading out of Africa through the Sahara, the Nile Valley, and the Red Sea coast have been proposed as migration routes for anatomically modern humans 80,000-130,000 years ago. During this time climate conditions in the Sahara were wetter than present day, and monsoon rainfall fed rivers that flowed across the desert landscape. The location and timing of these rivers may have supported human migration northward from central Africa to the Mediterranean coast, and onwards to Europe or Asia. Here, we use palaeoclimate rainfall and a hydrological model to spatially simulate and quantitatively test the existence of three major rivers crossing the Sahara from south to north during the time of human migration. We provide evidence that, given realistic underlying climatology, the well-known Sahabi and Kufrah rivers very likely flowed across modern day Libya and reached the coast. More unexpectedly an additional river crossed the core of the Sahara through Algeria (Irharhar river) and flowed into the Chotts basin. The Irharhar river is unique, because it links locations in central Africa experiencing monsoon climates with temperate coastal Mediterranean environments where food and resources were likely abundant. From an ecological perspective, this little-known corridor may prove to be the most parsimonious migration route. Support for the Irharar as a viable migration corridor is provided by its geographic proximity to middle Stone Age archaeological artefacts found in North Africa. Our new, highly novel approach provides the first quantitative analysis of the likelihood that rivers occurred during the critical period of human migration out of Africa. Simulated probability of surface water in North Africa during the last interglacial and the location of tools and ornaments from the Middle Stone Age.

  2. Survival of migrating salmon smolts in large rivers with and without dams.

    PubMed

    Welch, David W; Rechisky, Erin L; Melnychuk, Michael C; Porter, Aswea D; Walters, Carl J; Clements, Shaun; Clemens, Benjamin J; McKinley, R Scott; Schreck, Carl

    2008-10-28

    The mortality of salmon smolts during their migration out of freshwater and into the ocean has been difficult to measure. In the Columbia River, which has an extensive network of hydroelectric dams, the decline in abundance of adult salmon returning from the ocean since the late 1970s has been ascribed in large measure to the presence of the dams, although the completion of the hydropower system occurred at the same time as large-scale shifts in ocean climate, as measured by climate indices such as the Pacific Decadal Oscillation. We measured the survival of salmon smolts during their migration to sea using elements of the large-scale acoustic telemetry system, the Pacific Ocean Shelf Tracking (POST) array. Survival measurements using acoustic tags were comparable to those obtained independently using the Passive Integrated Transponder (PIT) tag system, which is operational at Columbia and Snake River dams. Because the technology underlying the POST array works in both freshwater and the ocean, it is therefore possible to extend the measurement of survival to large rivers lacking dams, such as the Fraser, and to also extend the measurement of survival to the lower Columbia River and estuary, where there are no dams. Of particular note, survival during the downstream migration of at least some endangered Columbia and Snake River Chinook and steelhead stocks appears to be as high or higher than that of the same species migrating out of the Fraser River in Canada, which lacks dams. Equally surprising, smolt survival during migration through the hydrosystem, when scaled by either the time or distance migrated, is higher than in the lower Columbia River and estuary where dams are absent. Our results raise important questions regarding the factors that are preventing the recovery of salmon stocks in the Columbia and the future health of stocks in the Fraser River. PMID:18959485

  3. Upstream migration of Pacific lampreys in the John Day River, Oregon: Behavior, timing, and habitat use

    USGS Publications Warehouse

    Robinson, T. Craig; Bayer, J.M.

    2005-01-01

    Adult Pacific lamprey migration and habitat preferences for over-winter holding and spawning, and larval rearing in tributaries to the Columbia River are not well understood. The John Day River is one such tributary where larval and adult stages of this species have been documented, and its free-flowing character provided the opportunity to study migration of Pacific lampreys unimpeded by passage constraints. Forty-two adult Pacific lampreys were captured in the John Day River near its mouth during their upstream migration. Pacific lampreys were surgically implanted with radio transmitters and released onsite, and tracked by fixed-site, aerial, and terrestrial telemetry methods for nearly one year. Adults moved upstream exclusively at night, with a mean rate of 11.1 ?? 6.3 km/day. They halted upstream migration by September, and held a single position for approximately six months in the lateral margins of riffles and glides, using boulders for cover. More than half of Pacific lampreys resumed migration in March before ending movement in early May. Pacific lampreys that resumed migration in spring completed a median of 87% of their upstream migration before over-winter holding. Upon completing migration. Pacific lampreys briefly held position before beginning downstream movement at the end of May. Though not directly observed, halting migration and movement downstream were likely the result of spawning and death. Gains in adult Pacific lamprey passage through the Columbia River hydrosystem and tributaries may be made by improvements that would expedite migration during spring and summer and increase the quantity and variety of cover and refuge opportunities. ?? 2005 by the Northwest Scientific Association. All rights reserved.

  4. The Wavelet ToolKat: A set of tools for the analysis of series through wavelet transforms. Application to the channel curvature and the slope control of three free meandering rivers in the Amazon basin.

    NASA Astrophysics Data System (ADS)

    Vaudor, Lise; Piegay, Herve; Wawrzyniak, Vincent; Spitoni, Marie

    2016-04-01

    The form and functioning of a geomorphic system result from processes operating at various spatial and temporal scales. Longitudinal channel characteristics thus exhibit complex patterns which vary according to the scale of study, might be periodic or segmented, and are generally blurred by noise. Describing the intricate, multiscale structure of such signals, and identifying at which scales the patterns are dominant and over which sub-reach, could help determine at which scales they should be investigated, and provide insights into the main controlling factors. Wavelet transforms aim at describing data at multiple scales (either in time or space), and are now exploited in geophysics for the analysis of nonstationary series of data. They provide a consistent, non-arbitrary, and multiscale description of a signal's variations and help explore potential causalities. Nevertheless, their use in fluvial geomorphology, notably to study longitudinal patterns, is hindered by a lack of user-friendly tools to help understand, implement, and interpret them. We have developed a free application, The Wavelet ToolKat, designed to facilitate the use of wavelet transforms on temporal or spatial series. We illustrate its usefulness describing longitudinal channel curvature and slope of three freely meandering rivers in the Amazon basin (the Purus, Juruá and Madre de Dios rivers), using topographic data generated from NASA's Shuttle Radar Topography Mission (SRTM) in 2000. Three types of wavelet transforms are used, with different purposes. Continuous Wavelet Transforms are used to identify in a non-arbitrary way the dominant scales and locations at which channel curvature and slope vary. Cross-wavelet transforms, and wavelet coherence and phase are used to identify scales and locations exhibiting significant channel curvature and slope co-variations. Maximal Overlap Discrete Wavelet Transforms decompose data into their variations at a series of scales and are used to provide

  5. Individual variation in migration speed of upriver-migrating sockeye salmon in the Fraser River in relation to their physiological and energetic status at marine approach.

    PubMed

    Hanson, Kyle C; Cooke, Steven J; Hinch, Scott G; Crossin, Glenn T; Patterson, David A; English, Karl K; Donaldson, Michael R; Shrimpton, J Mark; Van Der Kraak, Glen; Farrell, Anthony P

    2008-01-01

    Little research has examined individual variation in migration speeds of Pacific salmon (Oncorhynchus spp.) in natural river systems or attempted to link migratory behavior with physiological and energetic status on a large spatial scale in the wild. As a model, we used three stocks of summer-run sockeye salmon (Oncorhynchus nerka) from the Fraser River watershed, British Columbia, to test the hypothesis that individual variation in migration speed is determined by a combination of environmental factors (i.e., water temperature), intrinsic biological differences (sex and population), and physiological and energetic condition. Before the freshwater portion of the migration, sockeye salmon (Quesnel, Chilcotin, and Nechako stock complexes) were captured in Johnstone Strait ( approximately 215 km from river entry), gastrically implanted with radio transmitters, and sampled for blood, gill tissue, and energetic status before release. Analyses focused solely on individuals that successfully reached natal subwatersheds. Migration speeds were assessed by an extensive radiotelemetry array. Individuals from the stock complex that migrated the longest distance (Nechako) traveled at speeds slower than those of other stock complexes. Females traveled slower than males. An elevated energetic status of fish in the ocean was negatively correlated with migration speed in most river segments. During the transition from the ocean to the river, migration speed was negatively correlated with mean maximum water temperature; however, for the majority of river segments, it was positively correlated with migration speed. Physiological status measured in the ocean did not explain among-individual variability in river migration speeds. Collectively, these findings suggest that there could be extensive variation in migration behavior among individuals, sexes, and populations and that physiological condition in the ocean explained little of this variation relative to in-river environmental

  6. Modeling the stratigraphy and preservation potential of meandering stream deposits

    NASA Astrophysics Data System (ADS)

    Tucker, G. E.; Clevis, Q.; Lock, G.; Lancaster, S.; Desitter, A.

    2003-12-01

    Both natural and human-induced modes of river and floodplain behavior have the potential to obscure, expose, or even destroy portions of the archaeological record. In valley systems with actively meandering channels much material can be lost to lateral bank erosion. Conversely, floodplain aggradation can bury and therefore obscure sites. In this study we aim to quantify the preservation potential of fluvial units containing archaeological sites as a function of the natural process of meandering, climate change and increased land-use during the Holocene. We used the CHILD simulation model of landscape evolution to explore alternative scenarios in which these three factors are both varied independently and combined. Boundary and initial conditions for the model scenarios are based on the Holocene evolution of the archaeologically-rich Upper Thames Valley, which is known to have witnessed variations in flood frequency, land-clearance, episodic alluviation and river entrenchment. The CHILD model is set up to combine four components that simulate the development of valley and floodplain system: hillslope and channel erosion, lateral stream meandering, overbank deposition, and the accumulation of a 3D stratigraphy. The landscape is represented by an adaptable triangular mesh of nodes, especially suited for simulating the gradual shifting of meander bends. The new stratigraphic layering routine recently added to the model in improves the resolution of the stratigraphic record accumulated by the model. Simulation results reveal systematic controls on preservation potential, and suggest potential sources of bias in the archaeological record.

  7. Environmental correlates of upstream migration of yellow-phase American eels in the Potomac River drainage

    USGS Publications Warehouse

    Welsh, Stuart; Heather L. Liller,

    2013-01-01

    Assessing the relationships between upstream migration and environmental variables is important to understanding the ecology of yellow-phase American Eels Anguilla rostrata. During an American Eel migration study within the lower Shenandoah River (Potomac River drainage), we counted and measured American Eels at the Millville Dam eel ladder for three periods: 14 May–23 July 2004, 7–30 September 2004, and 1 June–31 July 2005. Using generalized estimating equations, we modeled each time series of daily American Eel counts by fitting time-varying environmental covariates of lunar illumination (LI), river discharge (RD), and water temperature (WT), including 1-d and 2-d lags of each covariate. Information-theoretic approaches were used for model selection and inference. A total of 4,847 American Eels (19–74 cm total length) used the ladder during the three periods, including 2,622 individuals during a 2-d span following a hurricane-induced peak in river discharge. Additive-effects models of RD + WT, a 2-d lag of LI + RD, and LI + RD were supported for the three periods, respectively. Parameter estimates were positive for river discharge for each time period, negative for lunar illumination for two periods and positive for water temperature during one period. Additive-effects models supported synergistic influences of environmental variables on the upstream migration of yellow-phase American Eels, although river discharge was consistently supported as an influential correlate of upstream migration.

  8. Quantifying Knick Point Migration Rates Related to the Messinian Crisis. The Case of the Nile River

    NASA Astrophysics Data System (ADS)

    Stüwe, Kurt; Pucher, Christoph; Robl, Jörg; Hergarten, Stefan

    2016-04-01

    The Messinian crisis is a temporally well-constrained period between 5.3 my and 5.9 my, when the strait of Gibraltar was tectonically closed and the Mediterranean Sea had consequently desiccated. This dramatic base level drop by about 1500 vertical meters had a profound influence on the geomorphic evolution of the major drainages surrounding the Mediterranean basin. In particular, it caused substantial knickpoints in the major rivers including the Rhone, the Ebro, the Po and the Nile. While the knickpoints of the Rhone and Ebro have been studied previously and the knickpoints created by the Po may lie today underneath the Po plains, the knickpoint and its migration along the Nile has not been studied and would have migrated along its current river channel. In this contribution we focus on numerical modelling of the knickpoint migration in the Nile and use our modelling results in comparison with the present day morphological analyses of the river to constrain absolute migration rates. We suspect that the first Nile cataract near Assuan, some 1000 km upstream of today's river mouth may be the relict of the Messinian salinity crisis making it to one of the fastest migrating knickpoints in the world.

  9. Seasonal migration and homing of channel catfish in the lower Wisconsin River, Wisconsin

    USGS Publications Warehouse

    Pellett, Thomas D.; Van Dyck, Gene J.; Adams, Jean V.

    1998-01-01

    A multiyear tag and recapture study was conducted to determine whether channel catfishIctalurus punctatus were migratory and if they had strong homing tendencies. Over 10,000 channel catfish were tagged from the lower Wisconsin River and adjacent waters of the upper Mississippi River during the 3-year sampling period. Data on movements were obtained from study recaptures and through tag returns and harvest information provided by sport anglers and commercial fishers. Channel catfish occupied relatively small home ranges during summer, migrated downstream to the upper Mississippi River in autumn, then migrated back up the Wisconsin River in spring to spawn and to occupy the same summer home sites they had used in previous summers. Fish size was a factor in the degree of fidelity to summer home sites, with larger fish showing greater fidelity.

  10. Three-dimensional flow structure and patterns of bed shear stress in an evolving compound meander bend

    USGS Publications Warehouse

    Engel, Frank; Rhoads, Bruce L.

    2016-01-01

    Compound meander bends with multiple lobes of maximum curvature are common in actively evolving lowland rivers. Interaction among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound bends is poorly understood. In this paper, acoustic Doppler current profiler (ADCP) measurements of the three-dimensional (3D) flow velocities in a compound bend are examined to evaluate the influence of channel curvature and hydrologic variability on the structure of flow within the bend. Flow structure at various flow stages is related to changes in bed morphology over the study timeframe. Increases in local curvature within the upstream lobe of the bend reduce outer bank velocities at morphologically significant flows, creating a region that protects the bank from high momentum flow and high bed shear stresses. The dimensionless radius of curvature in the upstream lobe is one-third less than that of the downstream lobe, with average bank erosion rates less than half of the erosion rates for the downstream lobe. Higher bank erosion rates within the downstream lobe correspond to the shift in a core of high velocity and bed shear stresses toward the outer bank as flow moves through the two lobes. These erosion patterns provide a mechanism for continued migration of the downstream lobe in the near future. Bed material size distributions within the bend correspond to spatial patterns of bed shear stress magnitudes, indicating that bed material sorting within the bend is governed by bed shear stress. Results suggest that patterns of flow, sediment entrainment, and planform evolution in compound meander bends are more complex than in simple meander bends. Moreover, interactions among local influences on the flow, such as woody debris, local topographic steering, and locally high curvature, tend to cause compound bends to evolve toward increasing planform complexity over time rather than stable configurations.

  11. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 2000 Annual Report.

    SciTech Connect

    Achord, Stephen

    2001-08-01

    This report details the 2000 results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends in the cumulative data collected for this project from Oregon and Idaho streams since 1989.

  12. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1996 Annual Report.

    SciTech Connect

    Achord, Stephen; Sandford, Benjamin P.; Hockersmith, Eric E.

    1997-07-01

    We PIT tagged wild spring/summer chinook salmon parr in the Snake River Basin in 1995 and subsequently monitored these fish during their smolt migration through Lower Granite, Little Goose, Lower Monumental, McNary, John Day, and Bonneville Dams during spring and summer 1996.

  13. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1999 Annual Report.

    SciTech Connect

    Achord, Stephen

    2001-06-01

    This report details the 1999 results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends in the cumulative data collected for this project from Oregon and Idaho streams since 1989.

  14. Monitoring the Migrations of Wild Snake River Spring and Summer Chinook Salmon Smolts, 1992 Annual Report.

    SciTech Connect

    Achord, Stephen; Marsh, Douglas M.; Kamikawa, Daniel J.

    1994-09-01

    We PIT tagged wild spring and summer chinook salmon parr in the Snake River Basin in 1991, and subsequently monitored these fish during their smolt migration through Lower Granite, Little Goose, and McNary Dams during spring and summer 1992. This report details our findings.

  15. Optical remote sensing of bedforms in a field-scale meandering channel

    NASA Astrophysics Data System (ADS)

    Palmsten, M. L.; Kozarek, J. L.; Calantoni, J.

    2012-12-01

    The morphology and migration rate of bedforms in a sandy meander vary as a result of differences in boundary shear stress around the meander bend. The objective of this work is to quantify bedform size and migration rate using synoptic observations of remotely sensed water depth around a meander bend. We conducted an experiment from 9-20 July 2012 at the Saint Anthony Falls Laboratory Outdoor StreamLab (OSL), University of Minnesota. The OSL consists of a bedload dominated, sandy (D50 = 0.7 mm) meandering channel approximately 40 m in length, 2.7 m in width, and 0.3 m in depth. Riffles were installed upstream and downstream of the meander bend. Discharge was fixed at 199 L/s throughout the experiment and sediment feed rate was 4.1 kg/min. Four color video cameras were mounted on a tower 5 m above the floodplain on the inner bank of the meander looking down into the stream. Two additional cameras, including one near infra-red camera were mounted on the outer bank of the meander. Video data were supplemented by 1 mm resolution measurements of velocity and sonar observations of bed elevation. The sonar and video data were used to create a transfer function between pixel intensity and water depth and pixel location was corrected for refraction, resulting ~0.01 m resolution depth measurements along the entire meander bend. Initially, the stream bed was flat. A pool formed immediately downstream of the riffle. A point bar and ripples developed during the first hour of the experiment. The morphology of bedforms changed with position around the meander bend from convex upstream to convex downstream. The sinuosity of bedforms also increased around the meander bend, reaching maximum near the bend apex. Bedform wavelength increased around the meander bend from 0.5 m upstream of the bend apex to > 1.5 m downstream of the bed apex. Bedform spacing increased as alternating bedforms increased in amplitude while neighboring bedforms decreased in amplitude until they disappeared

  16. Spawning migration of telemetered striped bass in the Roanoke River, North Carolina

    USGS Publications Warehouse

    Carmichael, J.T.; Haeseker, S.L.; Hightower, J.E.

    1998-01-01

    The spring spawning migration is a key period for effective management of anadromous populations of striped bass Morone saxatilis. Information on migratory behavior is needed in order to develop appropriate harvest regulations and to conduct effective surveys while fish are on the spawning grounds. We used ultrasonic telemetry to estimate the timing and duration of the upriver spawning migration for the Roanoke River, North Carolina, population and to evaluate whether a short-term fluctuation in temperature or flow would alter the distribution of telemetered fish on the spawning grounds. Seventy-eight fish implanted with transmitters were released during 1993 and 1994. Twenty-nine telemetered fish migrated upriver in 1994, and 14 telemetered fish entered the river in 1995. Migration of telemetered fish began in mid- to late April when water temperatures in the lower river reached 17-18??C. Males began their spawning migration significantly earlier than females in 1994; the difference was not significant in 1995. The 165-km upriver migration took about a week, as did the downriver migration after the spawning season. In 1994 and 1995 respectively, males remained on the spawning grounds for averages of 22 and 21 d, females for 8 and 11 d. Because of shorter residency times only about half the telemetered females were on the spawning grounds at any one time during the peak of the spawning season. Striped bass remained on the spawning grounds during a short-term temperature decrease of about 4??C (over 5 d) and an increase in flow from about 190 to 390 m3/s (over 1 d).

  17. The Effect of Alternating Bars Migration on River Bifurcation Dynamics

    NASA Astrophysics Data System (ADS)

    Miori, S.; Bertoldi, W.; Repetto, R.; Zanoni, L.; Tubino, M.

    2007-12-01

    Recent theoretical analysis, field and laboratory observations pointed out that fluvial bifurcation show an intrinsic instability, leading to the establishment of an unbalanced flow and sediments distribution in the downstream branches. The existence of equilibrium configurations has been proved, which mainly depend on the hydraulic and morphologic conditions of the upstream flow. However, flow and sediment transport in braided networks are highly unsteady, so that the bifurcation can hardly reach an equilibrium configuration. One of the main causes of temporal fluctuations is the migration of alternate bars in the upstream channel, that can affect and control the flow partition in the distributaries. We analysed the bar - bifurcation interactions by experimental and analytical investigations. We performed a set of flume experiments on a Y shaped fixed banks and movable bed bifurcation. Laboratory results show that bar formation in the upstream channel perturbs the discharge distribution with a series of fluctuations strictly related to the period of bar migration. Four different behaviours have been identified, characterised by small perturbations of the equilibrium state (balanced or unbalanced), by the occurrence of large fluctuations or by the closure of one of the distributaries. The character of the bifurcation is controlled by the amplitude and speed of alternate bars that directly influence the amplitude and period of discharge oscillations. Consequently, at large values of the aspect ratio (high bars) and low sediment mobility (slow bars) the bifurcation dynamics is likely to be dominated by bars migration. Extending the one-dimensional model proposed by Bolla Pittaluga et al. (2003), we introduce the effect of bars migrating in the upstream channel. In the present model, the bifurcation is forced with spatial crosswise fluctuations of feeding conditions, in order to reproduce the transverse distribution of sediment and water of an alternate bar pattern as

  18. Migration of precocious male hatchery chinook salmon in the Umatilla River, Oregon

    USGS Publications Warehouse

    Zimmerman, C.E.; Stonecypher, R.W.; Hayes, M.C.

    2003-01-01

    Between 1993 and 2000, precocious yearling males of hatchery-produced fall and spring chinook salmon Oncorhynchus tshawytscha composed 3.6-82.1% of chinook salmon runs to the Umatilla River, Oregon. These yearling males are smaller than typical jack salmon, which spend a full winter in the ocean, and are commonly referred to as "mini jacks." Minijack fall chinook salmon are characterized by enlarged testes and an increased gonadosomatic index. Our goal was to determine if minijacks migrated to saltwater between the time they are released from the hatchery and the time they return to the Umatilla River, a period of 4-6 months. During 1999-2000, we collected otoliths from an adult male fall chinook salmon, 12 spring chinook salmon minijacks, and 10 fall chinook salmon minijacks. We measured strontium:calcium (Sr:Ca) ratios from the age-1 annulus to the edge of the otolith to determine whether these fish had migrated to the ocean. The Sr:Ca ratios increased from low values near the age-1 annulus, similar to ratios expected from freshwaters, to higher values near the edge of the otolith. The Sr:Ca ratios increased to levels similar to ratios expected in saltwater, indicating that these fish had migrated to saltwater before returning to the Umatilla River. Analysis of published water chemistry data from the Columbia and Snake rivers and rearing experiments in the main-stem Columbia River confirmed that high Sr:Ca ratios measured in otoliths were not the result of high strontium levels encountered in the freshwater environment. Previously assumed to remain within freshwater and near the point of release, our results suggest these minijack salmon migrated at least 800 km and past three hydroelectric dams to reach saltwater and return to the Umatilla River.

  19. Meander cutoff and the controls on the production of oxbow lakes

    NASA Astrophysics Data System (ADS)

    Constantine, José Antonio; Dunne, Thomas

    2008-01-01

    Using satellite images archived by Google EarthTM, we measuredchannel and oxbow-lake characteristics of 30 large meanderingrivers to identify the controls on the production of oxbow lakesby meander cutoff. Cutoff produced lognormal distributions oflake lengths within the studied reaches, and the geometric meanlake length of each population correlated positively and exponentiallywith sinuosity, due to more highly sinuous reaches being comprisedof longer meanders and to cutoff removing longer segments ofmore sinuous channels. We successfully predicted the size-frequencydistributions of lakes stored within the flood-plains of fivefreely meandering reaches using only channel sinuosity and anassumption of the variance about the geometric mean lake length,a variable that did not significantly vary between the studiedreaches. While the river's sinuosity remains steady, the temporalrate of cutoff can be estimated using channel sinuosity, thefraction by which cutoff reduces channel length, and the rateat which the reach lengthens by meander growth.

  20. Interactions between hyporheic flow produced by stream meanders, bars, and dunes

    USGS Publications Warehouse

    Stonedahl, Susa H.; Harvey, Judson W.; Packman, Aaron I.

    2013-01-01

    Stream channel morphology from grain-scale roughness to large meanders drives hyporheic exchange flow. In practice, it is difficult to model hyporheic flow over the wide spectrum of topographic features typically found in rivers. As a result, many studies only characterize isolated exchange processes at a single spatial scale. In this work, we simulated hyporheic flows induced by a range of geomorphic features including meanders, bars and dunes in sand bed streams. Twenty cases were examined with 5 degrees of river meandering. Each meandering river model was run initially without any small topographic features. Models were run again after superimposing only bars and then only dunes, and then run a final time after including all scales of topographic features. This allowed us to investigate the relative importance and interactions between flows induced by different scales of topography. We found that dunes typically contributed more to hyporheic exchange than bars and meanders. Furthermore, our simulations show that the volume of water exchanged and the distributions of hyporheic residence times resulting from various scales of topographic features are close to, but not linearly additive. These findings can potentially be used to develop scaling laws for hyporheic flow that can be widely applied in streams and rivers.

  1. Mississippi River and Sea Surface Height Effects on Oil Slick Migration

    PubMed Central

    Falcini, Frederico; Jerolmack, Douglas J.; Buongiorno Nardelli, Bruno

    2012-01-01

    Millions of barrels of oil escaped into the Gulf of Mexico (GoM) after the 20 April, 2010 explosion of Deepwater Horizon (DH). Ocean circulation models were used to forecast oil slick migration in the GoM, however such models do not explicitly treat the effects of secondary eddy-slopes or Mississippi River (MR) hydrodynamics. Here we report oil front migration that appears to be driven by sea surface level (SSL) slopes, and identify a previously unreported effect of the MR plume: under conditions of relatively high river discharge and weak winds, a freshwater mound can form around the MR Delta. We performed temporal oil slick position and altimeter analysis, employing both interpolated altimetry data and along-track measurements for coastal applications. The observed freshwater mound appears to have pushed the DH oil slick seaward from the Delta coastline. We provide a physical mechanism for this novel effect of the MR, using a two-layer pressure-driven flow model. Results show how SSL variations can drive a cross-slope migration of surface oil slicks that may reach velocities of order km/day, and confirm a lag time of order 5–10 days between mound formation and slick migration, as observed form the satellite analysis. Incorporating these effects into more complex ocean models will improve forecasts of slick migration for future spills. More generally, large SSL variations at the MR mouth may also affect the dispersal of freshwater, nutrients and sediment associated with the MR plume. PMID:22558317

  2. Mississippi River and sea surface height effects on oil slick migration.

    PubMed

    Falcini, Frederico; Jerolmack, Douglas J; Nardelli, Bruno Buongiorno

    2012-01-01

    Millions of barrels of oil escaped into the Gulf of Mexico (GoM) after the 20 April, 2010 explosion of Deepwater Horizon (DH). Ocean circulation models were used to forecast oil slick migration in the GoM, however such models do not explicitly treat the effects of secondary eddy-slopes or Mississippi River (MR) hydrodynamics. Here we report oil front migration that appears to be driven by sea surface level (SSL) slopes, and identify a previously unreported effect of the MR plume: under conditions of relatively high river discharge and weak winds, a freshwater mound can form around the MR Delta. We performed temporal oil slick position and altimeter analysis, employing both interpolated altimetry data and along-track measurements for coastal applications. The observed freshwater mound appears to have pushed the DH oil slick seaward from the Delta coastline. We provide a physical mechanism for this novel effect of the MR, using a two-layer pressure-driven flow model. Results show how SSL variations can drive a cross-slope migration of surface oil slicks that may reach velocities of order km/day, and confirm a lag time of order 5-10 days between mound formation and slick migration, as observed form the satellite analysis. Incorporating these effects into more complex ocean models will improve forecasts of slick migration for future spills. More generally, large SSL variations at the MR mouth may also affect the dispersal of freshwater, nutrients and sediment associated with the MR plume. PMID:22558317

  3. Evaluating spawning migration patterns and predicting spawning success of shovelnose sturgeon in the Lower Missouri River

    USGS Publications Warehouse

    Wildhaber, M.L.; Holan, S.H.; Davis, G.M.; Gladish, D.W.; DeLonay, A.J.; Papoulias, D.M.; Sommerhauser, D.K.

    2011-01-01

    Approaches using telemetry, precise reproductive assessments, and surgically implanted data storage tags (DSTs) were used in combination with novel applications of analytical techniques for fish movement studies to describe patterns in migratory behavior and predict spawning success of gravid shovelnose sturgeon. From 2004 to 2007, over 300 gravid female shovelnose sturgeon (Scaphirhynchus platorynchus) from the Lower Missouri River, that were expected to spawn in the year they were collected, were surgically implanted with transmitters and archival DSTs. Functional cluster modeling of telemetry data from the spawning season suggested two common migration patterns of gravid female shovelnose sturgeon. Fish implanted from 958 to 1181 river kilometer (rkm) from the mouth of the Missouri River (or northern portion of the Lower Missouri River within 354rkm of the lowest Missouri River dam at rkm 1305) had one migration pattern. Of fish implanted from 209 to 402rkm from the mouth of the Missouri River (or southern portion of the Lower Missouri River), half demonstrated a movement pattern similar to the northern fish while the other half demonstrated a migration pattern that covered more of the river. There was no apparent difference in migration patterns between successful and unsuccessful spawners. Multiple hypotheses exist to explain differences in migratory patterns among fish from different river reaches. Additional work is required to determine if observed differences are due to multiple adapted strategies, environmental alteration, and/or initial tagging date. Hierarchical Bayesian modeling of DST data indicated that variation in depth usage patterns was consistently different between successful and unsuccessful spawners, as indicated by differences in likelihood of switching between high and low variability states. Analyses of DST data, and data collected at capture, were sufficient to predict 8 of 10 non-spawners/incomplete spawners and all 30 spawners in the

  4. Evaluating spawning migration patterns and predicting spawning success of shovelnose sturgeon in the Lower Missouri River

    USGS Publications Warehouse

    Wildhaber, M.L.; Holan, S.H.; Davis, G.M.; Gladish, D.W.; DeLonay, A.J.; Papoulias, D.M.; Sommerhauser, D.K.

    2011-01-01

    Approaches using telemetry, precise reproductive assessments, and surgically implanted data storage tags (DSTs) were used in combination with novel applications of analytical techniques for fish movement studies to describe patterns in migratory behavior and predict spawning success of gravid shovelnose sturgeon. From 2004 to 2007, over 300 gravid female shovelnose sturgeon (Scaphirhynchus platorynchus) from the Lower Missouri River, that were expected to spawn in the year they were collected, were surgically implanted with transmitters and archival DSTs. Functional cluster modeling of telemetry data from the spawning season suggested two common migration patterns of gravid female shovelnose sturgeon. Fish implanted from 958 to 1181 river kilometer (rkm) from the mouth of the Missouri River (or northern portion of the Lower Missouri River within 354 rkm of the lowest Missouri River dam at rkm 1305) had one migration pattern. Of fish implanted from 209 to 402 rkm from the mouth of the Missouri River (or southern portion of the Lower Missouri River), half demonstrated a movement pattern similar to the northern fish while the other half demonstrated a migration pattern that covered more of the river. There was no apparent difference in migration patterns between successful and unsuccessful spawners. Multiple hypotheses exist to explain differences in migratory patterns among fish from different river reaches. Additional work is required to determine if observed differences are due to multiple adapted strategies, environmental alteration, and/or initial tagging date. Hierarchical Bayesian modeling of DST data indicated that variation in depth usage patterns was consistently different between successful and unsuccessful spawners, as indicated by differences in likelihood of switching between high and low variability states. Analyses of DST data, and data collected at capture, were sufficient to predict 8 of 10 non-spawners/incomplete spawners and all 30 spawners in the

  5. Spawning migration movements of Lost River and shortnose suckers in the Williamson and Sprague Rivers, Oregon, following the removal of Chiloquin Dam-2009 Annual Report

    USGS Publications Warehouse

    Ellsworth, Craig M.; VanderKooi, Scott P.

    2011-01-01

    The Chiloquin Dam was located at river kilometer (rkm) 1.3 on the Sprague River near the town of Chiloquin, Oregon. The dam was identified as a barrier that potentially inhibited or prevented the upstream spawning migrations and other movements of endangered Lost River suckers (Deltistes luxatus), shortnose suckers (Chasmistes brevirostris), and other fish in the Sprague River. Our research objectives in 2009 were to evaluate adult catostomid spawning migration patterns using radio telemetry to identify and describe shifts in spawning area distribution and migration behavior following the removal of Chiloquin Dam in 2008. We attached external radio transmitters to 58 Lost River suckers and 59 shortnose suckers captured at the Williamson River fish weir. A total of 17 radio-tagged Lost River suckers and one radio-tagged shortnose sucker were detected approaching the site of the former Chiloquin Dam but only two radio-tagged fish (one male Lost River sucker and one female Lost River sucker) were detected crossing upstream of the dam site. A lower proportion of radio-tagged shortnose suckers were detected migrating into the Sprague River when compared with previous years. Detections on remote passive integrated transponder (PIT) tag arrays located in the Sprague River show that although the proportion of fish coming into the Sprague River is small when compared to the number of fish crossing the Williamson River fish weir, the number of fish migrating upstream of the Chiloquin Dam site increased exponentially in the first year since its removal. These data will be used in conjunction with larval production and adult spawning distribution data to evaluate the effectiveness of dam removal in order to provide increased access to underutilized spawning habitat located further upstream in the Sprague River and to reduce the crowding of spawning fish below the dam site.

  6. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1994-1995 Progress (Annual) Report.

    SciTech Connect

    Achord, Stephen

    1996-09-01

    We PIT tagged wild spring/summer chinook-salmon parr in the Snake River Basin in 1994 and subsequently monitored these fish during their smolt migration through Lower Granite, Little Goose, Lower Monumental, McNary, John Day, and Bonneville Darns during spring, summer, and fall 1995. This report details our findings. The goals of this study are to (1) characterize the migration timing of different wild stocks of Snake River spring/summer chinook salmon smolts at dams on the Snake and Columbia Rivers, (2) determine if consistent patterns are apparent, and (3) determine what environmental factors influence migration timing.

  7. Gulf sturgeon spawning migration and habitat in the Choctawhatchee River system, Alabama-Florida

    USGS Publications Warehouse

    Fox, D.A.; Hightower, J.E.; Parauka, F.M.

    2000-01-01

    Information about spawning migration and spawning habitat is essential to maintain and ultimately restore populations of endangered and threatened species of anadromous fish. We used ultrasonic and radiotelemetry to monitor the movements of 35 adult Gulf sturgeon Acipenser oxyrinchus desotoi (a subspecies of the Atlantic sturgeon A. oxyrinchus) as they moved between Choctawhatchee Bay and the Choctawhatchee River system during the spring of 1996 and 1997. Histological analysis of gonadal biopsies was used to determine the sex and reproductive status of individuals. Telemetry results and egg sampling were used to identify Gulf sturgeon spawning sites and to examine the roles that sex and reproductive status play in migratory behavior. Fertilized Gulf sturgeon eggs were collected in six locations in both the upper Choctawhatchee and Pea rivers. Hard bottom substrate, steep banks, and relatively high flows characterized collection sites. Ripe Gulf sturgeon occupied these spawning areas from late March through early May, which included the interval when Gulf sturgeon eggs were collected. For both sexes, ripe fish entered the Choctawhatchee River significantly earlier and at a lower water temperature and migrated further upstream than did nonripe fish. Males entered the Choctawhatchee River at a lower water temperature than females. Results from histology and telemetry support the hypothesis that male Gulf sturgeon may spawn annually, whereas females require more than 1 year between spawning events. Upper river hard bottom areas appear important for the successful spawning of Gulf sturgeon, and care should be taken to protect against habitat loss or degradation of known spawning habitat.

  8. [Sources, Migration and Conversion of Dissolved Sterols in Qingmuguan Underground River].

    PubMed

    Liang, Zuo-bing; Shen, Li-cheng; Sun, Yu-chuan; Wang, Zun-bo; Jiang, Ze-li; Zhang Mei; LIAO, Yu; Xie, Zheng-lan; Zhang, Yuan-zhu

    2015-11-01

    Water samples were collected from the Qinmuguan underground river from July to November in 2013. By gas chromatography-mass spectrometer (GC-MS), dissolved sterols were quantitatively analyzed. The results show that the average variation content of dissolved sterols ranges from 415 to 629 ng x L(-1), with the increasing migration distance of dissolved sterols in underground river, its contents are decreased. Between the inlet and outlet of Qingmuguan underground river, the average variation contents of dissolved sterol are between 724 and 374 ng x L(-1), and the average variation ratios of the content of stigmasterol with cholesterol range from 0.29 to 0.12. In short, their values are decreased accompanied by the increasing migration distance of underground river. The composing component in dissolved sterols varied differently between July to December, and the main component of dissolved sterols is cholesterin, the ratios of the content of dissolved sterols with cholesterin to the total dissolved sterols range from 37.30% to 94.85%. In addition, the ratios of the content of dissolved sterols with coprostanol to cholesterin, coprostanol to cholesterin are below 0.2 respectively, indicating the water quality of underground river is not contaminated by domestic sewage, but with the passage of time water quality tends to deterioration.

  9. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1994 Annual Report.

    SciTech Connect

    Achord, Stephen; Matthews, Gene M.; Kamikawa, Daniel J.

    1995-09-01

    The goals of this study are to (1) characterize the outmigration timing of different wild stocks of spring/summer chinook salmon smolts at dams on the Snake and Columbia Rivers, (2) determine if consistent patterns are apparent, and (3) determine what environmental factors influence outmigration timing. The authors PIT tagged wild spring/summer chinook salmon parr in the Snake River Basin in 1993, and subsequently monitored these fish during their smolt migration through Lower Granite, Little Goose, Lower Monumental, and McNary Dams during spring, summer, and fall 1994. This report details their findings.

  10. Stratigraphy, depositional history, and trapping mechanisms of Lone Tree Creek and Lodgepole Creek oil fields, Lower Cretaceous Fall River formation, Powder River Basin, Wyoming

    SciTech Connect

    Gustason, E.R.; Ryer, T.A.

    1985-05-01

    Stratigraphically trapped accumulations of oil in the Lone Tree Creek and Lodgepole Creek fields occur within and just updip from a fluvial meander belt within the Fall River Formation. The meander belt can be mapped north-to-south over a distance of at least 100 mi (161 km) in the eastern part of the Powder River basin. The northern part of the meander belt contains the oil fields of the Coyote Creek-Miller Creek trend; the southern part contains only the relatively small Lone Tree Creek and Lodgepole Creek fields. These small fields are of considerable interest, as they display a style of stratigraphic trapping of hydrocarbons not observed in the prolific Coyote Creek-Miller Creek trend. The stratigraphic traps of the Coyote Creek-Miller Creek trend occur at updip facing convexities along the eastern edge of the meander belt, with abandonment clay plugs serving as lateral permeability barriers to hydrocarbon migration. Oil has been produced in part of the Lone Tree Creek field from a similar trap. The remaining part of Lone Tree Creek field and Lodgepole creek field produce from stratigraphic traps formed by lateral pinch-outs of delta-front sandstone bodies. These traps are situated updip from and apparently in continuity with the meander-belt deposits, indicating that they may have been charged with hydrocarbons that found their way through the clay-plug barriers along the margin of the meander belt. Similar, undiscovered traps may exist updip from Fall River meander belts elsewhere in the basin.

  11. Convergent Hydraulics and Knickpoint Migration in an Incising Gravel-Cobble River

    NASA Astrophysics Data System (ADS)

    Wyrick, J. R.; Pasternack, G. B.

    2007-12-01

    Regulated gravel-cobble rivers are known to incise, but the mechanism of incision is not well documented by process-based research. Widespread use of simple "stream power law" equations assumes that incision is caused by continuous downcutting that increases with discharge. To provide an alternate explanation that recognizes the inherent non-uniformity of natural channels, we hypothesize that regulated rivers experience waves of migrating knickpoints that retreat through riffles during low flow when riffle crests function as supercritical weirs and are rejuvenated by floods that downcut the intervening width-constricted pools. To test this new hypothesis, monitoring was performed on the rapidly incising 7-km Timbuctoo Bend of the lower Yuba River, CA, where 463,000 cubic meters of sediment have been scoured out in just the last seven years alone. Direct field measurements of velocity and depth fields were obtained at three migrating, horseshoe-shaped knickpoints in this reach. Also, detailed channel DEMs were obtained at different stages of knickpoint migration to track geomorphic change over seven years. At one of the knickpoints, a special torque sensor was deployed to map near-bed lift and drag stress components. Velocity fields reveal convergent hydraulics controlled by the horseshoe morphology that focus scour in the upstream center of the U-shape. At a relatively low discharge, supercritical flow and near-critical standing waves were observed. Furthermore, the peak near-bed drag stress that was directly measured exceeded 1000 Pa during this relatively low discharge regime, which explains why the bedforms are retreating so rapidly. These direct measurements were compared to similar measurements previously reported for horseshoe waterfalls analyzed in a flume, and will aid in determining the real mechanism for knickpoint migration and channel incision in regulated gravel-cobble rivers.

  12. Contrasted sediment processes and morphological adjustments in three successive cutoff meanders of the Danube delta

    NASA Astrophysics Data System (ADS)

    Tiron Duţu, Laura; Provansal, Mireille; Le Coz, Jérôme; Duţu, Florin

    2014-01-01

    Since the 1980s intensive anthropogenic disturbances have affected the channel of the St. George branch, the southern distributary of the Danube River. The meander cutoff programme since 1984-1988 induced different hydrosedimentary impacts on the local distribution of river flow velocities, discharge, and sediment fluxes between the former meanders and the man-made canals (Ichim and Radoane, 1986; Popa, 1997; Panin, 2003). This paper selects three large cutoff meander reaches of the St. George branch (the Mahmudia, Dunavăţ de Sus, and Dunavăţ de Jos meanders noted here as M1, M2, and M3, respectively) as an example to analyse the human impact in the Danube River delta. The diversion of the flow induces strong modifications by acceleration of the fluxes through the artificial canals combined with dramatically enhanced deposition in the former meander where it was observed in two cases (M1 and M3) with slight modifications in M2. An exceptional flood that occurred in April 2006 offered a good opportunity for scanning different cross sections of the meander systems. Bathymetry, flow velocity, suspended-load concentration, and liquid and solid discharge data were acquired throughout several cross sections of both natural channels and artificial canals of the three cutoffs, using acoustic Doppler current profiler (ADCP) technology, in order to investigate the distribution of the flow and sediment and its impact on the hydrosedimentary processes in each channelized reach and adjacent former meander. Therefore, the results obtained during the 2006 flood were referred to a long-term evolution (1970-2006), analysed by GIS techniques.

  13. 2D numerical modelling of meandering channel formation

    NASA Astrophysics Data System (ADS)

    XIAO, Y.; ZHOU, G.; YANG, F. S.

    2016-03-01

    A 2D depth-averaged model for hydrodynamic sediment transport and river morphological adjustment was established. The sediment transport submodel takes into account the influence of non-uniform sediment with bed surface armoring and considers the impact of secondary flow in the direction of bed-load transport and transverse slope of the river bed. The bank erosion submodel incorporates a simple simulation method for updating bank geometry during either degradational or aggradational bed evolution. Comparison of the results obtained by the extended model with experimental and field data, and numerical predictions validate that the proposed model can simulate grain sorting in river bends and duplicate the characteristics of meandering river and its development. The results illustrate that by using its control factors, the improved numerical model can be applied to simulate channel evolution under different scenarios and improve understanding of patterning processes.

  14. Disease Susceptibility of Hatchery Snake River Spring-Summer Chinook Salmon with Different Juvenile Migration Histories in the Columbia River.

    PubMed

    Arkoosh, Mary R; Kagley, Anna N; Anulacion, Bernadita F; Boylen, Deborah A; Sandford, Benjamin P; Loge, Frank J; Johnson, Lyndal L; Collier, Tracy K

    2006-12-01

    Various methods have been developed to mitigate the effects of dams on juvenile Pacific salmon Oncorhynchus spp. migrating to the Pacific Ocean through the Columbia River basin. In this study, we examined the health of hatchery Snake River spring and summer Chinook salmon relative to two mitigating strategies: dam bypass and transportation (e.g., barging). The health of out-migrants was assessed in terms of the difference in the incidence of mortality among fish, categorically grouped into no-bypass, bypass, and transportation life histories, in response to challenge with the marine pathogen Listonella anguillarum during seawater holding. These three life histories were defined as follows: (1) fish that were not detected at any of the juvenile bypass systems above Bonneville Dam were classified as having a no-bypass life history; (2) fish that were detected at one or more juvenile bypass systems above Bonneville Dam were classified as having a bypass life history; and (3) fish that were barged were classified as having the transportation life history. Barged fish were found to be less susceptible to L. anguillarum than in-river fish-whether bypassed or not-which suggests that transportation may help mitigate the adverse health effects of the hydropower system of the Columbia River basin on Snake River spring-summer Chinook salmon. The findings of this study are not necessarily transferable to other out-migrant stocks in the Columbia River basin, given that only one evolutionarily significant unit, that is, Snake River spring-summer Chinook salmon, was used in this study.

  15. Disease Susceptibility of Hatchery Snake River Spring-Summer Chinook Salmon with Different Juvenile Migration Histories in the Columbia River.

    PubMed

    Arkoosh, Mary R; Kagley, Anna N; Anulacion, Bernadita F; Boylen, Deborah A; Sandford, Benjamin P; Loge, Frank J; Johnson, Lyndal L; Collier, Tracy K

    2006-12-01

    Various methods have been developed to mitigate the effects of dams on juvenile Pacific salmon Oncorhynchus spp. migrating to the Pacific Ocean through the Columbia River basin. In this study, we examined the health of hatchery Snake River spring and summer Chinook salmon relative to two mitigating strategies: dam bypass and transportation (e.g., barging). The health of out-migrants was assessed in terms of the difference in the incidence of mortality among fish, categorically grouped into no-bypass, bypass, and transportation life histories, in response to challenge with the marine pathogen Listonella anguillarum during seawater holding. These three life histories were defined as follows: (1) fish that were not detected at any of the juvenile bypass systems above Bonneville Dam were classified as having a no-bypass life history; (2) fish that were detected at one or more juvenile bypass systems above Bonneville Dam were classified as having a bypass life history; and (3) fish that were barged were classified as having the transportation life history. Barged fish were found to be less susceptible to L. anguillarum than in-river fish-whether bypassed or not-which suggests that transportation may help mitigate the adverse health effects of the hydropower system of the Columbia River basin on Snake River spring-summer Chinook salmon. The findings of this study are not necessarily transferable to other out-migrant stocks in the Columbia River basin, given that only one evolutionarily significant unit, that is, Snake River spring-summer Chinook salmon, was used in this study. PMID:26599158

  16. [Downstream migration, behavior, and distribution of fish fry in the lower reaches of the Ozernaya River (southwestern Kamchatka)].

    PubMed

    Pavlov, D S; Kirillova, E A; Kirillov, P I; Nezdoliĭ, V K

    2015-01-01

    Fry of five species of salmonids are found in the lower reaches of the Ozernaya River. The most abundant are chum salmon and pink salmon which compose the bulk of fry which migrate downstream from the river to the sea. The dates and duration of migration of particular species differed according to the specific traits of their biology. Pink salmon is characterized by a simple migration strategy: it migrated downstream in a short time after emergence from theground. Chum salmon has two strategies of downstream migration: some fry start migration soon after emergence, and others remained in the river for several weeks. Downstream migration of pink salmon occurred mainly at night in contrast to that of chum salmon, over 24 h, the part of daytime increased with growth, of the fish. Migration of pink salmon was passive. Passive migration of chum salmon changed into active-passive with growth of the fish. The ratio of fish in the inshore zone and in the current was different in the course of 24 h. The number of fish in the inshore zone decreased in the period of intensive downstream migration.

  17. Migration and habitats of diadromous Danube River sturgeons in Romania: 1998-2000

    USGS Publications Warehouse

    Kynard, B.; Suciu, R.; Horgan, M.

    2002-01-01

    Upstream migrant adults of stellate sturgeon, Acipenser stellatus (10 in 1998, 43 in 1999) and Russian sturgeon, A. gueldenstaedtii (three in 1999) were captured at river km (rkm) 58-137, mostly in the spring, and tagged with acoustic tags offering a reward for return. The overharvest was revealed by tag returns (38% in 1998, 28% in 1999) and by harvest within 26 days (and before reaching spawning grounds) of the six stellate sturgeon tracked upstream. A drop-back of > 50% of the tagged sturgeon, some to the Black Sea, shows a high sensitivity to interruption of migration and capture/handling/holding. Harvesting and dropback prevented tracking of sturgeon to spawning sites. Gillnetting and tracking of stellate sturgeon showed that the autumn migration ended in early October (river temperature 16??C) and identified a likely wintering area at river km (rkm) 75-76 (St George Branch). Thus, fishery harvesting after early October captures wintering fish, not migrants. Rare shoreline cliffs in the lower river likely create the only rocky habitat for sturgeon spawning. A survey for potential spawning habitats found five sites with rocky substrate and moderate water velocity, all ???rkm 258. Drift netting caught early life-stages of 17 fish species and one sturgeon, a beluga, Huso huso, larva likely spawned at ???rkm 258. All diadromous Danube sturgeons likely spawn at ???rkm 258.

  18. Migration patterns of Neolithic settlements on the abandoned Yellow and Yangtze River deltas of China

    NASA Astrophysics Data System (ADS)

    Chen, Zhongyuan; Zong, Yongqiang; Wang, Zhanghua; Wang, Hui; Chen, Jing

    2008-09-01

    Archaeological records of the Neolithic settlements on the eastern China coast between 35°N and 30°N, an area covering the abandoned Yellow River and the Yangtze River delta plains, reveal that Neolithic people moved from the Yellow River basin onto the northern coast for fishing, hunting and dry-land agriculture ~ 7000 yr ago. Marine transgression interrupted their activities on the low-lying (2-5 m in elevation) coastal wetlands between 6000 and 5000 yr ago, after which they reclaimed their land near the river mouths. Their migration routes on the southern Yangtze delta plain indicate another scenario: early Neolithic communities moved onto the plain for wet-rice cultivation. Despite relative sea-level rise from 7000 to 4000 yr ago, a large number of settlements were established on the lowlands between the eastern Chenier Ridges and the western Taihu Lake depression. The Chenier Ridges, with ~ 1.0 m higher topography than the adjacent coastal area, played a role in sheltering the Neolithic people. Subsequently, settlements waned considerably, possibly due to further marine inundation combined with cold climate. The present study shows that migration patterns of the Neolithic settlements are closely associated with a gradually rising sea level between 7000 and 4000 yr ago.

  19. Measurements of American rivers clarify influences on sinuosity

    NASA Astrophysics Data System (ADS)

    Kiel, B.

    2013-12-01

    We used the National Hydrography Dataset (NHD) to measure river widths and sinuosities nationally. Sinuosities were measured over reaches scaled by river width; sinuosity values typically increase with increasing reach length. By using short reaches of ~1 meander arc length, we aim to isolate sinuosity of channels meandering within floodplains. Spatial averaging of sinuosity over the eastern half of the U.S.--where measurements are dense--produces an intuitive map that we deem more useful than individual measurements. Sinuosity exhibits the following correlations: drainage density r = -0.34; soil sand content r = 0.54; land slope r = -0.37. We submit that lateral erosion of bend outer banks in sinuous rivers is driven by a self-reinforcing mass balance cycle wherein sand eroded from outer banks sustains point bar lateral accretion, which in turn sustains outer bend lateral erosion and forces passive lateral flow migration away from the advancing point bar.

  20. Testing the Role of Meander Cutoff in Promoting Gene Flow across a Riverine Barrier in Ground Skinks (Scincella lateralis)

    PubMed Central

    Jackson, Nathan D.; Austin, Christopher C.

    2013-01-01

    Despite considerable attention, the long-term impact of rivers on species diversification remains uncertain. Meander loop cutoff (MLC) is one river phenomenon that may compromise a river’s diversifying effects by passively transferring organisms from one side of the river to the other. However, the ability of MLC to promote gene flow across rivers has not been demonstrated empirically. Here, we test several predictions of MLC-mediated gene flow in populations of North American ground skinks (Scincella lateralis) separated by a well-established riverine barrier, the Mississippi River: 1) individuals collected from within meander cutoffs should be more closely related to individuals across the river than on the same side, 2) individuals within meander cutoffs should contain more immigrants than individuals away from meander cutoffs, 3) immigration rates estimated across the river should be highest in the direction of the cutoff event, and 4) the distribution of alleles native to one side of the river should be better predicted by the historical rather than current path of the river. To test these predictions we sampled 13 microsatellite loci and mitochondrial DNA from ground skinks collected near three ancient meander loops. These predictions were generally supported by genetic data, although support was stronger for mtDNA than for microsatellite data. Partial support for genetic divergence of samples within ancient meander loops also provides evidence for the MLC hypothesis. Although a role for MLC-mediated gene flow was supported here for ground skinks, the transient nature of river channels and morphologies may limit the long-term importance of MLC in stemming population divergence across major rivers. PMID:23658778

  1. Hydraulic Characteristics of the Lower Snake River During Periods of Juvenile Fall Chinook Migration

    SciTech Connect

    Cook, Chris B.; Dibrani, Berhon; Richmond, Marshall C.; Bleich, Matthew D.; Titzler, P. Scott; Fu, Tao

    2006-01-30

    This report documents a four-year study to assess hydraulic conditions in the lower Snake River. The work was conducted for the Bonneville Power Administration, U.S. Department of Energy, by the Pacific Northwest National Laboratory. Cold water released from the Dworshak Reservoir hypolimnion during mid- to late-summer months cools the Clearwater River far below equilibrium temperature. The volume of released cold water augments the Clearwater River, and the combined total discharge is on the order of the Snake River discharge when the two rivers meet at their confluence near the upstream edge of Lower Granite Reservoir. With typical temperature differences between the Clearwater and Snake rivers of 10°C or more during July and August, the density difference between the two rivers during summer flow augmentation periods is sufficient to stratify Lower Granite Reservoir as well as the other three reservoirs downstream. Because cooling of the river is desirable for migrating juvenile fall Chinook salmon (Oncorhynchus tshawytscha) during this same time period, the amount of mixing and cold water entrained into Lower Granite Reservoir’s epilimnion at the Clearwater/Snake River confluence is of key biological importance to juvenile fall Chinook salmon. Data collected during this project indicates the three reservoirs downstream of Lower Granite also stratify as direct result of flow augmentation from Dworshak Reservoir. These four lower Snake reservoirs are also heavily influenced by wind forcing at the water’s surface, and during periods of low river discharge, often behave like a two-layer lake. During these periods of stratification, lower river discharge, and wind forcing, the water in the upper layer of the reservoir is held in place or moves slightly upstream. This upper layer is also exposed to surface heating and may warm up to temperatures close to equilibrium temperature. The depth of this upper warm layer and its direction of travel may also be of key

  2. Electronic tags and genetics explore variation in migrating steelhead kelts (oncorhynchus mykiss), Ninilchik river, Alaska

    USGS Publications Warehouse

    Nielsen, J.L.; Turner, S.M.; Zimmerman, C.E.

    2011-01-01

    Acoustic and archival tags examined freshwater and marine migrations of postspawn steelhead kelts (Oncorhynchus mykiss) in the Ninilchik River, Alaska, USA. Postspawn steelhead were captured at a weir in 2002-2005. Scale analysis indicated multiple migratory life histories and spawning behaviors. Acoustic tags were implanted in 99 kelts (2002-2003), and an array of acoustic receivers calculated the average speed of outmigration, timing of saltwater entry, and duration of residency in the vicinity of the river mouth. Ocean migration data were recovered from two archival tags implanted in kelts in 2004 (one male and one female). Archival tags documented seasonal differences in maximum depth and behavior with both fish spending 97% of time at sea <6 m depth (day and night). All study fish were double tagged with passive integrated transponder (PIT) tags implanted in the body cavity. Less than 4% of PIT tags were retained in postspawn steelhead. Molecular genetics demonstrated no significant differences in genetic population structure across years or among spawning life history types, suggesting a genetically panmictic population with highly diverse life history characteristics in the Ninilchik River.

  3. Self-Formed Meanders (With Cutoffs) in a Laboratory Flume

    NASA Astrophysics Data System (ADS)

    Braudrick, C. A.; Leverich, G. T.; Sklar, L. S.; Dietrich, W. E.

    2005-12-01

    The development of a mechanistic understanding of channel geometry and morphodynamics has been inhibited by the inability to create self-formed, freely meandering, single thread channels in a laboratory flume. By being able to reliably generate such channels, studies of the influence of sediment supply and flow dynamics as well as bank strength on channel morphology can be experimentally explored. We have found that the key experimental controls are: 1) ratio of bank strength to boundary shear stress exerted on the bank; 2) bedload and suspended load rates; and 3) variable flow discharge. We have been able to create meandering channels in a sand bedded laboratory flume using alfalfa sprouts. The alfalfa sprouts decrease the bank erosion rate so that bank erosion would occur at approximately the same pace as bar growth. The addition of coarse suspended load was necessary to cause deposition on bars to grow to the floodplain height. The sprouts contributed to deposition by creating a rough floodplain surface. Steady discharge failed to produced meandering, apparently due to the lack of suspended load deposition on the bar surface. The channels were created in a 3.6-m wide and 6.1-m long flume with an adjustable slope set at 0.01. We introduced both bedload (sand) and suspended load (crushed silica) into the top of the flume, which has an initial channel with either one or two bends carved into the floodplain. Runs lasted between 1 and 4 hours and occurred once per week. Alfalfa seeds were spread evenly outside the low flow channel following each run and are allowed to grow between runs. With the same material and flow conditions, the channel rapidly braided without the alfalfa sprouts. Braided was also favored under steady flow conditions. Under dynamic flows with banks strengthened by sprouts, the resulting experimental channels had many of the features observed in meandering streams such as oxbow lakes and meander cutoffs. The cutoffs occurred during overbank flows

  4. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1998 Annual Report.

    SciTech Connect

    Achord, Stephen; Hockersmith, Eric E.; Axel, Gordon A.

    2000-12-01

    This reports details the 1998 study results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends observed in the cumulative data resulting from this project; data has been collected from Oregon and Idaho streams since 1989. The project was initiated after 3 years of detection data from PIT-tags (passive-integrated-transponder tags) had shown distinct differences in migration patterns between wild and hatchery fish. Data showing these patterns had originated from tagging and interrogation operations begun in 1988 to evaluate a smolt transportation program conducted by the National Marine Fisheries Service (NMFS) for the US Army Corps of Engineers. In 1991, the Bonneville Power Administration began a cooperative effort with NMFS to expand tagging and interrogation of wild fish for this project. Project goals were to characterize the outmigration timing of these fish, to determine whether consistent migration patterns would emerge, and to investigate the influence of environmental factors on the timing and distribution of these migrations. In 1992, the Oregon Department of Fish and Wildlife (ODFW) began an independent program of PIT tagging wild chinook salmon parr in the Grande Ronde and Imnaha River Basins in northeast Oregon. Since then, ODFW has reported all tagging, detection, and timing information on fish from these streams. However, with ODFW concurrence, NMFS will continue to report arrival timing of these fish at Lower Granite Dam. We continued to tag fish from Idaho in all years subsequent to 1992. Principal results from our tagging and interrogation efforts during 1997-1998 are given.

  5. Field Investigation of Flow Structure and Channel Morphology at Confluent-Meander Bends

    NASA Astrophysics Data System (ADS)

    Riley, J. D.; Rhoads, B. L.

    2007-12-01

    The movement of water and sediment through drainage networks is inevitably influenced by the convergence of streams and rivers at channel confluences. These focal components of fluvial systems produce a complex hydrodynamic environment, where rapid changes in flow structure and sediment transport occur to accommodate the merging of separate channel flows. The inherent geometric and hydraulic change at confluences also initiates the development of distinct geomorphic features, reflected in the bedform and shape of the channel. An underlying assumption of previous experimental and theoretical models of confluence dynamics has been that converging streams have straight channels with angular configurations. This generalized conceptualization was necessary to establish confluence planform as symmetrical or asymmetrical and to describe subsequent flow structure and geomorphic features at confluences. However, natural channels, particularly those of meandering rivers, curve and bend. This property and observation of channel curvature at natural junctions have led to the hypothesis that natural stream and river confluences tend to occur on the concave outer bank of meander bends. The resulting confluence planform, referred to as a confluent-meander bend, was observed over a century ago but has received little scientific attention. This paper examines preliminary data on three-dimensional flow structure and channel morphology at two natural confluent-meander bends of varying size and with differing tributary entrance locations. The large river confluence of the Vermilion River and Wabash River in west central Indiana and the comparatively small junction of the Little Wabash River and Big Muddy Creek in southeastern Illinois are the location of study sites for field investigation. Measurements of time-averaged three-dimensional velocity components were obtained at these confluences with an acoustic Doppler current profiler for flow events with differing momentum ratios. Bed

  6. Migration and spawning of radio-tagged zulega Prochilodus argenteus in a dammed Brazilian river

    USGS Publications Warehouse

    Godinho, Alexandre L.; Kynard, B.

    2006-01-01

    It is difficult for agencies to evaluate the impacts of the many planned dams on Sa??o Francisco River, Brazil, migratory fishes because fish migrations are poorly known. We conducted a study on zulega Prochilodus argenteus, an important commercial and recreational fish in the Sa??o Francisco River, to identify migrations and spawning areas and to determine linear home range. During two spawning seasons (2001-2003), we radio-tagged fish in three main-stem reaches downstream of Tre??s Marias Dam (TMD), located at river kilometer (rkm) 2,109. We tagged 10 fish at Tre??s Marias (TM), which is 5 km downstream of TMD; 12 fish at Pontal, which is 28 km downstream of TMD and which includes the mouth of the Abaete?? River, and 10 fish at Cilga, which is 45 km downstream of TMD. Late-stage (ripe) adults tagged in each area during the spawning season remained at or near the tagging site, except for four Cilga fish that went to Pontal and probably spawned. The Pontal area at the Abaete?? River mouth was the most important spawning site we found. Prespawning fish moved back and forth between main-stem staging areas upstream of the Abaete?? River mouth and Pontal for short visits. These multiple visits were probably needed as ripe fish waited for spawning cues from a flooding Abaete?? River. Some fish homed to prespaw ning staging areas, spawning areas, and nonspawning areas. The migratory style of zulega was dualistic, with resident and migratory fish. Total linear home range was also dualistic, with small (<26-km) and large (53-127-km) ranges. The locations of spawning areas and home ranges suggest that the Pontal group (which includes Cilga fish) is one population that occupies about 110 km. The Pontal population overlaps a short distance with a population located downstream of Cilga. Movements of late-stage TM adults suggest that the TM group is a separate population, possibly with connections to populations upstream of TMD. ?? Copyright by the American Fisheries Society

  7. Thermal exposure of juvenile fall chinook salmon migrating through a lower Snake River Reservoir

    USGS Publications Warehouse

    Tiffan, K.F.; Haskell, C.A.; Rondorf, D.W.

    2003-01-01

    Impoundment of the Snake River, Washington, has resulted in high water temperatures and late seaward migration of juvenile fall chinook salmon during summer months. To determine if juvenile fall chinook salmon are exposed to temperatures higher than the upper incipient lethal, we tagged groups of fish with temperature-sensing radio tags and tracked them in Little Goose Reservoir on the Snake River during the summers of 1998 and 1999. Spatial and temporal patterns of the reservoir's thermal environment were described using a bathythermograph. Little Goose Reservoir was generally homothermic, and temperatures selected by fish were typically not significantly different from mean water temperatures. No areas of thermal refugia existed in Little Goose Reservoir. Thermal exposure was most influenced by fish residence time in the reservoir within each year and by temperature differences between years. Current augmentation of Snake River summer flows with cold-water releases from Dworshak Dam in Idaho reduces the thermal exposure of juvenile fall chinook salmon by lowering water temperatures up to 4??C and may therefore increase their survival. Continued flow augmentation using water from Dworshak Reservoir may be the only mechanism to meet the temperature standard for the lower Snake River.

  8. Influences of body size and environmental factors on autumn downstream migration of bull trout in the Boise River, Idaho

    USGS Publications Warehouse

    Monnot, L.; Dunham, J.B.; Hoem, T.; Koetsier, P.

    2008-01-01

    Many fishes migrate extensively through stream networks, yet patterns are commonly described only in terms of the origin and destination of migration (e.g., between natal and feeding habitats). To better understand patterns of migration in bull trout,Salvelinus confluentus we studied the influences of body size (total length [TL]) and environmental factors (stream temperature and discharge) on migrations in the Boise River basin, Idaho. During the autumns of 2001-2003, we tracked the downstream migrations of 174 radio-tagged bull trout ranging in size from 21 to 73 cm TL. The results indicated that large bull trout (>30 cm) were more likely than small fish to migrate rapidly downstream after spawning in headwater streams in early autumn. Large bull trout also had a higher probability of arriving at the current terminus of migration in the system, Arrowrock Reservoir. The rate of migration by small bull trout was more variable and individuals were less likely to move into Arrowrock Reservoir. The rate of downstream migration by all fish was slower when stream discharge was greater. Temperature was not associated with the rate of migration. These findings indicate that fish size and environmentally related changes in behavior have important influences on patterns of migration. In a broader context, these results and other recent work suggest, at least in some cases, that commonly used classifications of migratory behavior may not accurately reflect the full range of behaviors and variability among individuals (or life stages) and environmental conditions. ?? Copyright by the American Fisheries Society 2008.

  9. Migrations and swimming capabilities of endangered pallid sturgeon (Scaphirhynchus albus) to guide passage designs in the fragmented Yellowstone River

    USGS Publications Warehouse

    Braaten, P. J.; Elliott, Caroline M.; Rhoten, Jason C.; Fuller, D. B.; McElroy, Brandon J.

    2015-01-01

    Fragmentation of the Yellowstone River is hypothesized to preclude recruitment of endangered Scaphirhynchus albus (pallid sturgeon) by impeding upstream spawning migrations and access to upstream spawning areas, thereby limiting the length of free-flowing river required for survival of early life stages. Building on this hypothesis, the reach of the Yellowstone River affected by Intake Diversion Dam (IDD) is targeted for modification. Structures including a rock ramp and by-pass channel have been proposed as restoration alternatives to facilitate passage. Limited information on migrations and swimming capabilities of pallid sturgeon is available to guide engineering design specifications for the proposed structures. Migration behavior, pathways (channel routes used during migrations), and swimming capabilities of free-ranging wild adult pallid sturgeon were examined using radiotelemetry, and complemented with hydraulic data obtained along the migration pathways. Migrations of 12–26% of the telemetered pallid sturgeon population persisted to IDD, but upstream passage over the dam was not detected. Observed migration pathways occurred primarily through main channel habitats; however, migrations through side channels up to 3.9 km in length were documented. The majority of pallid sturgeon used depths of 2.2–3.4 m and mean water velocities of 0.89–1.83 m/s while migrating. Results provide inferences on depths, velocities, and habitat heterogeneity of reaches successfully negotiated by pallid sturgeon that may be used to guide designs for structures facilitating passage at IDD. Passage will provide connectivity to potential upstream spawning areas on the Yellowstone River, thereby increasing the likelihood of recruitment for this endangered species.

  10. Fluvial Responses to Growth Faulting in the West Pearl River, Louisiana

    NASA Astrophysics Data System (ADS)

    Prosser, S. A.; Yeager, K. M.

    2015-12-01

    The Pearl River Delta (PRD) in southeastern Louisiana is an actively deforming deltaic complex displaying surface and near-surface evidence of growth faulting. Active growth faults in these environments are rarely identified at the surface, in part because the downthrown blocks often experience increased rates of sediment deposition leading to an obscured and low-relief, or entirely absent, surface expression. Faulting can be expressed in fluvial systems as changes in channel gradient, which often result in coincident changes in channel sinuosity, migration rates, planform deflections, and/or ponding features within the deformed zone. The study area is focused on a meander bend of the West Pearl River (WPR). The nature of the meander bend suggests the likely presence of a short growth fault controlling channel morphology. This research tested the hypotheses that active near-surface growth faulting is constraining the tortuous meander bend of the WPR and that growth faults, where present and active, are strongly coupled to channel meander planform changes and marsh vertical accretion rates in the PRD. Tools including shallow lithostratigraphy, use of fallout radionuclides (210Pb, 137Cs, 7Be) to quantify marsh vertical accretion rates, and a ~75 year record of WPR channel migration show that active growth faulting exists along the northern bend of the WPR with resultant lateral channel deflection. Evidence of this growth fault suggests further, eastward extension of the Baton Rouge Fault Zone (BRFZ) into the PRD

  11. Evidence for the migration of steroidal estrogens through river bed sediments.

    PubMed

    Labadie, Pierre; Cundy, Andrew B; Stone, Kevin; Andrews, Michael; Valbonesi, Sam; Hill, Elizabeth M

    2007-06-15

    Estrogenic substances discharged from wastewater treatment plants have been detected in surface sediments of receiving waters, but little is known of their vertical migration through buried sediments and their potential to contaminate subsurface waters. The vertical profiles of estrogenic chemicals were investigated in sediment cores at an alluvial freshwater site (Ditchling) and a clay-rich estuarine site (Lewes), both of which are downstream of wastewater discharges into the River Ouse (Sussex, U.K.). Estrone (E1) was the predominant estrogen detected in surface and buried sediments at both sites and was detected in undisturbed clay sediments > 120 years old. Profiles of E1 at Ditchling were characterized by a prominent subsurface peak of E1 at the alluvium/clay interface (-15 cm) at a concentration (28.8 +/- 6.0 ng/g of dry wt) that was 9-fold higher than in the surface sediment. In contrast, a steady downcore decline in E1 concentrations was observed in the clay-rich Lewes core. This work provides the first in situ evidence of estrogen migration through river bed sediments and reveals that movement of estrogens through unconsolidated sediment can result in penetration to the underlying substrata and therefore the potential for groundwater contamination.

  12. Assessment of long-term channel changes in the Mekong River using remote sensing and a channel-evolution model

    NASA Astrophysics Data System (ADS)

    Miyazawa, N.

    2011-12-01

    River-channel changes are a key factor affecting physical, ecological and management issues in the fluvial environment. In this study, long-term channel changes in the Mekong River were assessed using remote sensing and a channel-evolution model. A channel-evolution model for calculating long-term channel changes of a measndering river was developed using a previous fluid-dynamic model [Zolezzi and Seminara, 2001], and was applied in order to quantify channel changes of two meandering reaches in the Mekong River. Quite few attempts have been made so far to combine remote sensing observation of meandering planform change with the application of channel evolution models within relatively small-scale gravel-bed systems in humid temperate regions. The novel point of the present work is to link state-of-art meandering planform evolution model with observed morphological changes within large-scale sand-bed rivers with higher bank height in tropical monsoonal climate regions, which are the highly dynamic system, and assess the performance. Unstable extents of the reaches could be historically identified using remote-sensing technique. The instability caused i) bank erosion and accretion of meander bends and ii) movement or development of bars and changes in the flow around the bars. The remote sensing measurements indicate that maximum erosion occurred downstream of the maximum curvature of the river-center line in both reaches. The model simulations indicates that under the mean annual peak discharge the maximum of excess longitudinal velocity near the banks occurs downstream of the maximum curvature in both reaches. The channel migration coefficients of the reaches were calibrated by comparing remote-sensing measurements and model simulations. The diffrence in the migration coefficients between both reaches depends on the diffrence in bank height rather than the geotechnical properties of floodplain sediments. Possible eroded floodplain areas and accreted floodplain

  13. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1997 Annual Report.

    SciTech Connect

    Achord, Stephen; Eppard, M. Brad; Hockersmith, Eric E.

    1998-05-01

    In August 1996, we PIT tagged and released 1,360 wild chinook salmon parr in the South Fork of the Salmon River and two of its tributaries in Idaho. During spring and summer 1997, the overall adjusted percentage of PIT-tagged fish from Idaho detected at six downstream dams averaged 18.3% (range 16.0 to 27.3% depending on stream of origin). Peak detections of all wild spring/summer chinook salmon smolts (from Idaho and Oregon) at Lower Granite Dam occurred during variable but increasing river flows in April. High river flows from mid-April to mid-May moved most of these fish through Lower Granite Dam, with 50 and 90% passage occurring on 24 April and 21 May, respectively. From 1989 to 1996, peak detections of wild spring/summer chinook salmon smolts were highly variable and generally independent of river flows before about 9 May at this dam; however, during these years (including 1997), peak detections of wild fish coincided with periods of peak flow at the dam from 9 May to the end of May. In both 1995 and 1996, in excess of 90% of the wild fish had migrated past Lower Granite Dam by the time peak flows occurred in June. In 1989, we observed a period of peak detections of wild fish that coincided with peak flows at the dam in June. After examining chinook salmon smolt passage timing at the dams over the last 9 years, it has become clear that flow is only one of several factors that influence passage timing. Other factors, such as annual climatic conditions, water temperature, turbidity, physiological development, variability in stock behavior, fish size, and other yet unknown conditions may equally affect wild smolt passage timing at dams. As additional environmental monitors and traps are installed in study streams, we will be able to more accurately monitor parr and smolt movements out of rearing areas and examine the relationships of these movements to environmental parameters within the streams. Mapped over time, this information will provide the basis for

  14. Recruitment of Anguilla spp. glass eels in the Waikato River, New Zealand. Evidence of declining migrations?

    PubMed

    Jellyman, D J; Booker, D J; Watene, E

    2009-06-01

    The timing of Anguilla spp. glass eel recruitment into the Waikato River, North Island, New Zealand, was studied over a 2 year period (2004-2005). While glass eels of both the shortfin eel Anguilla australis and the endemic longfin eel Anguilla dieffenbachii were caught, the former comprised >97% of the species composition. There was a positive correlation of glass eel migrations with spring tides, with peak migration periods typically occurring within a few hours of the peak of high tide, and between 2 and 4 days after the day of spring tide. Both water temperature and discharge had significant inverse relationships with glass eel catches, with temperature explaining >30% of the variance in catch periodicity. Comparison of catch data 30 years apart showed that main migration periods appear to occur several weeks earlier today than previously. Reduced catch per unit effort and duration of runs from recent years' sampling (compared with the 1970s) indicate that a reduction in recruitment may also have occurred during this period, something recorded in other temperate species of Anguilla.

  15. Survival of migrating Atlantic salmon smolts through the Penobscot River, Maine: A pre-restoration assessment

    USGS Publications Warehouse

    Zydlewski, Joseph; Kinnison, Michael T.; Holbrook, Christopher M.

    2011-01-01

    Survival, distribution, and behavior of hatchery (n = 493) and naturally reared (n = 133) smolts of Atlantic salmon Salmo salar migrating through the Penobscot River and estuary in Maine were evaluated with acoustic telemetry in 2005 and 2006. Survival and use of a secondary migration path (the Stillwater Branch) were estimated with a multistate mark–recapture model. Higher rates of mortality per kilometer (range = 0.01–0.22) were observed near release sites and within reaches that contained three particular dams: Howland, West Enfield, and Milford dams. Estimated total survival of tagged hatchery smolts through entire individual reaches containing those dams ranged from 0.52 ( 0.18) to 0.94 ( 0.09), whereas survival through most of the reaches without dams exceeded 0.95. Of those smolts that survived to the Penobscot River–Stillwater Branch split at Marsh Island, most (≥74%) remained in the main stem around Marsh Island, where they experienced lower survival than fish that used the Stillwater Branch. Movement rates of hatchery-reared smolts were significantly lower through reaches containing dams than through reaches that lacked dams. Smolts arriving at dams during the day experienced longer delays than smolts arriving at night. Planned removal of two dams in this system is expected to enhance the passage of smolts through the main-stem corridor. However, the dams currently scheduled for removal (Great Works and Veazie dams) had less influence on smolt survival than some of the dams that will remain. This case study shows that by examining prerestoration migration dynamics throughout entire river systems rather than just in the vicinity of particular dams, tracking studies can help prioritize restoration efforts or predict the costs and benefits of future hydrosystem changes.

  16. Flow Structure and Channel Morphology at a Confluent-Meander Bend

    NASA Astrophysics Data System (ADS)

    Riley, J. D.; Rhoads, B. L.

    2009-12-01

    Flow structure and channel morphology in meander bends have been well documented. Channel curvature subjects flow through a bend to centrifugal acceleration, inducing a counterbalancing pressure-gradient force that initiates secondary circulation. Transverse variations in boundary shear stress and bedload transport parallel cross-stream movement of high velocity flow and determine spatial patterns of erosion along the outer bank and deposition along the inner bank. Laboratory experiments and numerical modeling of confluent-meander bends, a junction planform that develops when a tributary joins a meandering river along the outer bank of a bend, suggest that flow and channel morphology in such bends deviate from typical patterns. The purpose of this study is to examine three-dimensional (3-D) flow structure and channel morphology at a natural confluent-meander bend. Field data were collected in southeastern Illinois where Big Muddy Creek joins the Little Wabash River near a local maximum of curvature along an elongated meander loop. Measurements of 3-D velocity components were obtained with an acoustic Doppler current profiler (ADCP) for two flow events with differing momentum ratios. Channel bathymetry was also resolved from the four-beam depths of the ADCP. Analysis of velocity data reveals a distinct shear layer flanked by dual helical cells within the bend immediately downstream of the confluence. Flow from the tributary confines flow from the main channel along the inner part of the channel cross section, displacing the thalweg inward, limiting the downstream extent of the point bar, protecting the outer bank from erosion and enabling bar-building along this bank. Overall, this pattern of flow and channel morphology is quite different from typical patterns in meander bends, but is consistent with a conceptual model derived from laboratory experiments and numerical modeling.

  17. Survey of pathogens in hatchery Chinook salmon with different out-migration histories through the Snake and Columbia rivers.

    PubMed

    Van Gaest, A L; Dietrich, J P; Thompson, D E; Boylen, D A; Strickland, S A; Collier, T K; Loge, F J; Arkoosh, M R

    2011-06-01

    The operation of the Federal Columbia River Power System (FCRPS) has negatively affected threatened and endangered salmonid populations in the Pacific Northwest. Barging Snake River spring Chinook salmon Oncorhynchus tshawytscha through the FCRPS is one effort to mitigate the effect of the hydrosystem on juvenile salmon out-migration. However, little is known about the occurrence and transmission of infectious agents in barged juvenile salmon relative to juvenile salmon that remain in-river to navigate to the ocean. We conducted a survey of hatchery-reared spring Chinook salmon at various points along their out-migration path as they left their natal hatcheries and either migrated in-river or were barged through the FCRPS. Salmon kidneys were screened by polymerase chain reaction for nine pathogens and one family of water molds. Eight pathogens were detected; the most prevalent were Renibacterium salmoninarum and infectious hematopoietic necrosis virus. Species in the family Saprolegniaceae were also commonly detected. Pathogen prevalence was significantly greater in fish that were barged through the FCRPS than in fish left to out-migrate in-river. These results suggest that the transmission of infectious agents to susceptible juvenile salmon occurs during the barging process. Therefore, management activities that reduce pathogen exposure during barging may increase the survival of juvenile Chinook salmon after they are released.

  18. Downstream migration of recently metamorphosed sea lampreys in the Ocqueoc River, Michigan, before and after treatment with lampricides

    USGS Publications Warehouse

    Hanson, Lee H.; Swink, William D.

    1989-01-01

    The objectives of this study were to determine the effectiveness ofchemical treatments of the Ocqueoc River, Michigan, in reducing the number of recently metamorphosed sea lampreys Petromyzon marinus migrating to Lake Huron and to estimate total numbers of migrants produced before and after treatment. Sea lampreys were captured during their downstream migration in a single fyke net fished in the same location from September 1963 through August 1975. The catch, which averaged 3,474 sea lampreys (range, 3,248-3,913) during four migration periods (September-June) before treatment in 1968, declined to 4 during the 1974-1975 migration period. Markrecapture studies were conducted to determine the capture efficiency of the net for recently metamorphosed sea lampreys and to estimate the total downstream migration for each migration period. Estimated downstream migrations before treatment averaged 62,036 sea lampreys (range, 58,000-69,875) for four migration periods and declined to 71 during the 1974-1975 migration period. Catches were usually greater in fall than in spring. The fall peak in migratory activity was in November or December, and the spring peak was in April; both peaks occurred while water levels were high and water temperatures were near 5A?C.

  19. Sex biased survival and differences in migration of wild steelhead (Oncorhynchus mykiss) smolts from two coastal Oregon rivers

    USGS Publications Warehouse

    Thompson, Neil F.; Leblanc, Camille A.; Romer, Jeremy D.; Schreck, Carl B.; Blouin, Michael S.; Noakes, David L. G.

    2016-01-01

    In salmonids with partial migration, females are more likely than males to undergo smoltification and migrate to the ocean (vs. maturing in freshwater). However, it is not known whether sex affects survivorship during smolt migration (from fresh water to entry into the ocean). We captured wild steelhead (Oncorhynchus mykiss) smolts in two coastal Oregon rivers (USA) and collected fin tissue samples for genetic sex determination (2009; N = 70 in the Alsea and N = 69 in the Nehalem, 2010; N = 25 in the Alsea). We implanted acoustic tags and monitored downstream migration and survival until entry in to the Pacific Ocean. Survival was defined as detection at an estuary/ocean transition array. We found no effect of sex on smolt survivorship in the Nehalem River in 2009, or in the Alsea River in 2010. However, males exhibited significantly lower survival than females in the Alsea River during 2009. Residency did not influence this result as an equal proportion of males and females did not reach the estuary entrance (11% of males, 9% of females). The sexes did not differ in timing or duration of migration, so those variables seem unlikely to explain sex-biased survivorship. Larger males had higher odds of survival than smaller males in 2009, but the body size of females did not affect survivorship. The difference in survivorship between years in the Alsea River could be due to flow conditions, which were higher in 2010 than in 2009. Our findings suggest that sex may affect steelhead smolt survival during migration, but that the difference in survivorship may be weak and not a strong factor influencing adult sex ratios.

  20. Characterization of Wind Meandering in Low-Wind-Speed Conditions

    NASA Astrophysics Data System (ADS)

    Mortarini, Luca; Stefanello, Michel; Degrazia, Gervasio; Roberti, Debora; Trini Castelli, Silvia; Anfossi, Domenico

    2016-10-01

    Investigation of low-wind cases observed during the Urban Turbulent Project campaign (Torino, Italy) and at the Santa Maria meteorological station (Santa Maria, Brazil) provides insight into the wind-meandering phenomenon, i.e. large, non-turbulent oscillations of horizontal wind speed and temperature. Meandering and non-meandering cases are identified through analysis of the Eulerian autocorrelation functions of the horizontal wind-velocity components and temperature. When all three autocorrelation functions oscillate, meandering is present. As with weak turbulence, meandering shows no dependence on stability but is influenced by presence of buildings and depends on wind speed. We show that, while the standard deviation of the horizontal velocity is always large in low-wind conditions, the standard deviation of the vertical velocity shows very different behaviour in meandering and non-meandering conditions. In particular, the value of the ratio of the standard deviations of the vertical and horizontal velocities typifies the meandering condition.

  1. Summary of Migration and Survival Data from Radio-Tagged Juvenile Coho Salmon in the Trinity River, Northern California, 2008

    USGS Publications Warehouse

    Beeman, John W.; Hansel, Hal; Juhnke, Steve; Stutzer, Greg

    2009-01-01

    The survival of hatchery-origin juvenile coho salmon from the Trinity River Hatchery was estimated as they migrated seaward through the Trinity and Klamath Rivers. The purpose of the study was to collect data for comparison to a similar study in the Klamath River and provide data to the Trinity River Restoration Program. A total of 200 fish fitted with radio transmitters were released into the Trinity River near the hatchery (river kilometer 252 from the mouth of the Klamath River) biweekly from March 19 to May 28, 2008. Fish from the earliest release groups took longer to pass the first detection site 10 kilometers downstream of the hatchery than fish from the later release groups, but travel times between subsequent sites were often similar among the release groups. The travel times of individuals through the 239 kilometer study area ranged from 15.5 to 84.6 days with a median of 43.3 days. The data and models did not support differences in survival among release groups, but did support differences among river reaches. The probability of survival in the first 53 kilometers was lower than in the reaches farther downstream, which is similar to trends in juvenile coho salmon in the Klamath River. The lowest estimated survival in this study was in the first 10 kilometers from release in the Trinity River (0.676 SE 0.036) and the highest estimated survival was in the final 20 kilometer reach in the Klamath River (0.987 SE 0.013). Estimated survivals of radio-tagged juvenile coho salmon from release to Klamath River kilometer 33 were 0.639 per 100 kilometers for Trinity River fish and 0.721 per 100 kilometers for Klamath River fish.

  2. Lyme disease and migrating birds in the Saint Croix River Valley.

    PubMed

    Weisbrod, A R; Johnson, R C

    1989-08-01

    During a study of migrating land birds in 1987, we examined over 9,200 individual birds representing 99 species from the Saint Croix River Valley, a Lyme disease-endemic area of east central Minnesota and northwestern Wisconsin. We found that 250 deer tick (Ixodes dammini) larvae and nymphs infested 58 birds from 15 migrant species; 56 ticks (22.4%) were positive for the Lyme disease spirochete Borrelia burgdorferi. Five ground-foraging migrant bird species favoring mesic habitats, veery (Catharus fuscescens), ovenbird (Seiurus aurocapillus), northern waterthrush (S. novaboracensis), common yellowthroat (Geothlypis trichas), and swamp sparrow (Melospiza georgiana), accounted for nearly three-quarters of parasitized individuals. Nearly half of the spirochete-positive ticks were removed from migrating birds taken in a riparian floodplain forest. Recaptured migrants with infected ticks indicate that they transmit B. burgdorferi to hexapod larvae. We suggest that birds may be both an important local reservoir in the upper Mississippi Valley and long-distance dispersal agents for B. burgdorferi-infected ticks to other regions of the continent. PMID:2782872

  3. Fluvial responses to late Quaternary climate change in the Shiyang River drainage system, western China

    NASA Astrophysics Data System (ADS)

    Gao, Hongshan; Li, Zongmeng; Pan, Baotian; Liu, Fenliang; Liu, Xiaopeng

    2016-04-01

    As a drainage system located in arid western China, the Shiyang River, combined with considerable fluvial strata and landform information, provides an environmental context within which to investigate fluvial responses to late Quaternary climate change. Sedimentological analysis and optically stimulated luminescence (OSL) dating enabled us to reconstruct the processes and fluvial styles of three sedimentary sequences of the Shagou and Hongshui rivers in the Shiyang drainage system. Our results present a variety of river behaviors during the late Quaternary in these areas. In the upstream Shiyang River, Zhangjiadazhuang (ZJDZ) profile of the Shagou was dominated by aggradation and a meandering channel pattern at 10.6-4.2 ka, while a noticeable channel incision occurred at ~ 4.2 ka followed by lateral channel migration. In the downstream Shiyang River, Datugou (DTG) profile of the Hongshui was an aggrading meandering river from 39.7 to 7.2 ka while channel incision occurred at 7.2 ka. Another downstream profile, Wudunwan (WDW) of the Hongshui was also characterized by aggradation from 22.4 to 4.8 ka; however, its channel pattern shifted from braided to meandering at ~ 13 ka. A discernable downcutting event occurred at ~ 4.8 ka, followed by three channel aggradation and incision episodes prior to 1.8 ka. The last 1.8 ka has been characterized by modern channel and floodplain development. The fluvial processes and styles investigated have a close correlation with late Quaternary climate change in the Shiyang River drainage. During cold phases, the WDW reach was dominated by aggradation with a braided channel pattern. During warm phases, the rivers that we investigated were also characterized by aggradation but with meandering channel patterns. Channel incision events and changes of fluvial style occurred mainly during climate transitions.

  4. Effect of Migration Pathway on Travel Time and Survival of Acoustic-Tagged Juvenile Salmonids in the Columbia River Estuary

    SciTech Connect

    Harnish, Ryan A.; Johnson, Gary E.; McMichael, Geoffrey A.; Hughes, Michael S.; Ebberts, Blaine D.

    2012-02-01

    Off-channel areas (side channels, tidal flats, sand bars, and shallow-water bays) may serve as important migration corridors through estuarine environments for salmon and steelhead smolts. Relatively large percentages (21-33%) of acoustic-tagged yearling and subyearling Chinook salmon and steelhead smolts were detected migrating through off-channel areas of the Columbia River estuary in 2008. The probability of survival for off-channel migrants (0.78-0.94) was similar to or greater than the survival probability of main channel migrants (0.67-0.93). Median travel times were similar for all species or run types and migration pathways we examined, ranging from 1-2 d. The route used by smolts to migrate through the estuary may affect their vulnerability to predation. Acoustic-tagged steelhead that migrated nearest to avian predator nesting colonies experienced higher predation rates (24%) than those that migrated farthest from the colonies (10%). The use of multiple migration pathways may be advantageous to out-migrating smolts because it helps to buffer against high rates of mortality, which may occur in localized areas, and helps to minimize inter- and intraspecific competition.

  5. Ontogenetic behavior and migration of Volga River Russian sturgeon, Acipenser gueldenstaedtii, with a note on adaptive significance of body color

    USGS Publications Warehouse

    Kynard, B.; Zhuang, P.; Zhang, L.; Zhang, T.; Zhang, Z.

    2002-01-01

    We conducted laboratory experiments with Volga River Russian sturgeon, Acipenser gueldenstaedtii, to develop a conceptual model of early behavior. We daily observed fish from day-0 (embryos, first life interval after hatching) to day-29 feeding larvae for preference of bright habitat and cover, swimming distance above the bottom, up- and downstream movement, and diel activity. Hatchling embryos initiated a downstream migration, which suggests that predation risk of embryos at spawning sites is high. Migration peaked on days 0-5 and ceased on day 7 (8-day migration). Migrants preferred bright, open habitat and early migrants swam-up far above the bottom (maximum daily median, 140 cm) in a vertical swim tube. Post-migrant embryos did not prefer bright illumination but continued to prefer white substrate, increased use of cover habitat, and swam on the bottom. Larvae initiated feeding on day 10 after 170.6 cumulative temperature degree-days. Larvae did not migrate, weakly preferred bright illumination, preferred white substrate and open habitat, and swam near the bottom (daily median 5-78 cm). The lack of a strong preference by larvae for bright illumination suggests foraging relies more on olfaction than vision for locating prey. A short migration by embryos would disperse wild sturgeon from a spawning area, but larvae did not migrate, so a second later migration by juveniles disperses young sturgeon to the sea (2-step migration). Embryo and larva body color was light tan and tail color was black. The migration, behavior, and light body color of Russian sturgeon embryos was similar to species of Acipenser and Scaphirhynchus in North America and to Acipenser in Asia that migrate after hatching as embryos. The similarity in migration style and body color among species with diverse phylogenies likely reflects convergence for common adaptations across biogeographic regions. ?? 2002 Kluwer Academic Publishers.

  6. Distribution, migration and potential risk of heavy metals in the Shima River catchment area, South China.

    PubMed

    Gao, Lei; Chen, Jianyao; Tang, Changyuan; Ke, Zhiting; Wang, Jiang; Shimizu, Yuta; Zhu, Aiping

    2015-10-01

    The distribution, migration and potential risk of heavy metals in water and soil environments, related to city water supply, were investigated. Heavy metal concentrations in waters from the Shima River water ranged from not detected (n.d.) to 749 μg L(-1) for Mn, n.d. to 151 μg L(-1) for Ni, 7.00 to 494 μg L(-1) for Zn, n.d. to 93.0 μg L(-1) for Cu and n.d. to 9860 μg L(-1) for Fe. The highest concentration of heavy metals was found at an upstream site in February as a result of industrial effluent discharge. Groundwater (GW1-GW5) and soil (S1-S8) samples along the riverbank showed similar levels of contamination due to a close hydraulic relationship and frequent exchange of water, probably resulting in migration of heavy metals from river water to the aquifer and accumulation at the interface. The mean concentrations of heavy metals in soil profiles were in the ranges of 2.50-19.0 mg kg(-1) for As, 2.80-11.2 mg kg(-1) for Cd, 20.3-165 mg kg(-1) for Cr, 14.5-298 mg kg(-1) for Cu, 11.4-102 mg kg(-1) for Ni, 7.00-95.0 mg kg(-1) for Pb, 40.4-465 mg kg(-1) for Zn, 8.80 × 10(3)-21.8 × 10(3) mg kg(-1) for Fe, and 62.2-430 mg kg(-1) for Mn, showing severe soil pollution by Cd. LUMISTox testing and the potential ecological risk index (RI) were used to assess the potential for adverse ecological effects caused by heavy metals in water and soil media. River water samples posed slight acute toxicity to Vibrio fischeri with luminescence inhibition rates (LIRs) ranging from 24.6% to 38.4% in February. Elevated Zn and Cu concentrations significantly contributed to the toxicity. However, groundwater did not exhibit any toxicity to Vibrio fischeri. The severity of the potential ecological risk for individual metals (Er(i)) decreased in the order of Cd > Cu > Ni > As > Pb > Zn > Cr. RI values indicated that all soil samples in the study area posed a high level of ecological risk. Cd contributed significantly (95.5-98.9%) to potential ecological risk in soils.

  7. Geometry of meandering and braided gravel-bed threads from the Bayanbulak Grassland, Tianshan, P. R. China

    NASA Astrophysics Data System (ADS)

    Métivier, François; Devauchelle, Olivier; Chauvet, Hugo; Lajeunesse, Eric; Meunier, Patrick; Blanckaert, Koen; Ashmore, Peter; Zhang, Zhi; Fan, Yuting; Liu, Youcun; Dong, Zhibao; Ye, Baisheng

    2016-03-01

    The Bayanbulak Grassland, Tianshan, P. R. China, is located in an intramontane sedimentary basin where meandering and braided gravel-bed rivers coexist under the same climatic and geological settings. We report and compare measurements of the discharge, width, depth, slope and grain size of individual threads from these braided and meandering rivers. Both types of threads share statistically indistinguishable regime relations. Their depths and slopes compare well with the threshold theory, but they are wider than predicted by this theory. These findings are reminiscent of previous observations from similar gravel-bed rivers. Using the scaling laws of the threshold theory, we detrend our data with respect to discharge to produce a homogeneous statistical ensemble of width, depth and slope measurements. The statistical distributions of these dimensionless quantities are similar for braided and meandering threads. This suggests that a braided river is a collection of intertwined threads, which individually resemble those of meandering rivers. Given the environmental conditions in Bayanbulak, we furthermore hypothesize that bedload transport causes the threads to be wider than predicted by the threshold theory.

  8. Rate estimates for lateral bedrock erosion based on radiocarbon ages, Duck River, Tennessee

    SciTech Connect

    Brakenridge, G.R.

    1985-02-01

    Rates of bedrock erosion in ingrown meandering rivers can be inferred from the location of buried relict flood-plain and river-bank surfaces, associated paleosols, and radiocarbon dates. Two independent methods are used to evaluate the long-term rates of limestone bedrock erosion by the Duck River. Radiocarbon dates on samples retrieved from buried Holocene flood-plain and bank surfaces indicate lateral migration of the river bank at average rates of 0.6-1.9 m/100 yr. Such rates agree with lateral bedrock cliff erosion rates of 0.5-1.4 m/100 yr, as determined from a comparison of late Pleistocene and modern bedrock cliff and terrace scarp positions. These results show that lateral bedrock erosion by this river could have occurred coevally with flood-plain and terrace formation and that the resulting evolution of valley meander bends carved into bedrock is similar in many respects to that of channel meanders cut into alluvium. 11 references, 5 figures.

  9. Migration and spawning of female surubim (Pseudoplatystoma corruscans, Pimelodidae) in the São Francisco river, Brazil

    USGS Publications Warehouse

    Godinho, Alexandre L.; Kynard, Boyd; Godinho, Hugo P.

    2007-01-01

    Surubim, Pseudoplatystoma corruscans, is the most valuable commercial and recreational fish in the São Francisco River, but little is known about adult migration and spawning. Movements of 24 females (9.5–29.0 kg), which were radio-tagged just downstream of Três Marias Dam (TMD) at river kilometer 2,109 and at Pirapora Rapids (PR) 129 km downstream of TMD, suggest the following conceptual model of adult female migration and spawning. The tagged surubims used only 274 km of the main stem downstream of TMD and two tributaries, the Velhas and Abaeté rivers. Migration style was dualistic with non-migratory (resident) and migratory fish. Pre-spawning females swam at ground speeds of up to 31 km day-1 in late September–December to pre-spawning staging sites located 0–11 km from the spawning ground. In the spawning season (November–March), pre-spawning females migrated back and forth from nearby pre-spawning staging sites to PR for short visits to spawn, mostly during floods. Multiple visits to the spawning site suggest surubim is a multiple spawner. Most post-spawning surubims left the spawning ground to forage elsewhere, but some stayed at the spawning site until the next spawning season. Post-spawning migrants swam up or downstream at ground speeds up to 29 km day-1 during January–March. Construction of proposed dams in the main stem and tributaries downstream of TMD will greatly reduce surubim abundance by blocking migrations and changing the river into reservoirs that eliminate riverine spawning and non-spawning habitats, and possibly, cause extirpation of populations.

  10. Patterns of migration and residency in coastal cutthroat trout Oncorhynchus clarkii clarkii from two tributaries of the lower Columbia River

    USGS Publications Warehouse

    Zydlewski, G.B.; Zydlewski, J.; Johnson, J.

    2009-01-01

    Coastal cutthroat trout Onchorhynchus clarkii clarkii life-history variants, migration and freshwater residency were monitored using stationary passive integrated transponder (PIT) tag arrays in two tributaries of the Columbia River from 2001 to 2005 (Abernathy Creek, river kilometre, rkm 76) and from 2002 to 2005 (Chinook River, rkm 6). In 2001-2003 and 2002-2003 (Abernathy and Chinook, respectively), 300-500 coastal O. c. clarkii were captured in each tributary by electrofishing and implanted with 23 mm PIT tags. PIT arrays monitored movements from the initiation of tagging through the spring of 2005. Rotary screw traps were also operated on both tributaries. In Abernathy Creek, 28% of tagged individuals were observed through either active capture or passive interrogation. Of these, 32% were identified as migrants and 68% were identified as residents. In the Chinook River, 48% of tagged fish were observed subsequent to tagging; 92% of these fish were migrants and only 8% were resident. In both tributaries, a greater proportion of resident fish were in the upper reaches. The majority of migrants (78-93%) moved the spring following tagging. Migrants leaving at age 2+ years tended to grow faster than those that migrated at age 3+ years or residents. Patterns of growth or growth opportunities may influence both patterns of life-history expression and the timing of migration. ?? 2009 The Fisheries Society of the British Isles.

  11. Sinuosity and meander belt scarring: Tectonics and stream dynamics across the Baton Rouge Fault Zone

    NASA Astrophysics Data System (ADS)

    Dunek, P.; Gasparini, N.

    2009-12-01

    This study focuses on the sinuosity of alluvial rivers flowing across the Baton Rogue fault zone (BRFZ). The BRFZ is a little studied normal fault system extending roughly from Baton Rogue, LA east to about the Mississippi border. We hypothesize that the sinuosity is measurably different in channel reaches upstream and downstream of the fault trace. To gather sinuosity data we use two methods. The first is field surveying using a laser range finder and GPS; this method is only used over limited reaches, because covering the entire river system in this way is prohibitively time consuming. The second method uses ArcGIS to analyze LIDAR data that are freely available for the entire state of Louisiana. The LIDAR data have a 5 meter resolution. The largest channels are easily identified by eye in the LIDAR data and can be digitally traced by hand. On most of the smaller rivers, however, it is difficult to discern the exact trace of the channel. In these cases we use the ArcGIS hydrology tools to determine the path of the rivers. In order to check the accuracy we do this twice, once with the LIDAR data and once with the USGS 10 m data. However, the two data sets often produce very different river paths. Upon further investigation it appears that the rivers show a large amount of scarring throughout the meander belt, making it impossible to discern the exact trace of the channel. In fact, field surveying indicates that often times the channel traces from both data sets are incorrect. As a result, in areas where there is no clear channel trace, we calculate a local relief across the meander belt as a proxy for the degree of meandering. We find that in channels where it is possible to calculate sinuosity, there are distinct patterns related to local faulting; in those channels in which we cannot calculate sinuosity, meander belt relief patterns indicate increased channel meandering in proximity to the fault zone. The red and green paths correspond to the USGS 10m and LIDAR

  12. [Modeling of Processes of Migration and Accumulation of Radionuclides in Freshwater Ecosystems by the Example of the Samson, Lev, Vandras Rivers Related to the Ob-Irtysh River Basin].

    PubMed

    Trapeznikov, A V; Korzhavin, A V; Trapeznikova, V N; Nikolkin, V N

    2016-01-01

    Mathematical models of horizontal distribution and migration of radionuclides are presented in water and floodplain soils of the Samson-Lev-Vandras river system related to the Ob-Irtysh river basin. Integral inventory of radionuclides in the main components of the river ecosystems is calculated. The estimated annual discharge of radionuclides from the Vandras river to the Great Salym river is given. The effect of the removal of man-made radionuclides in the Samson, Lev, Vandras rivers on radioactive contamination of the Ob-Irtysh river system is shown in comparison with the Techa river, that also belongs to the Ob-Irtysh river basin. Despite the presence of an additional radioactive contamination of the Samson floodplain, the transfer of radioactive substances in the Samson, Lev, Vandras rivers has a much smaller impact on the contamination of the Ob-Irtysh river system, compared to the Techa river, prone to a large-scale radioactive contamination.

  13. [Modeling of Processes of Migration and Accumulation of Radionuclides in Freshwater Ecosystems by the Example of the Samson, Lev, Vandras Rivers Related to the Ob-Irtysh River Basin].

    PubMed

    Trapeznikov, A V; Korzhavin, A V; Trapeznikova, V N; Nikolkin, V N

    2016-01-01

    Mathematical models of horizontal distribution and migration of radionuclides are presented in water and floodplain soils of the Samson-Lev-Vandras river system related to the Ob-Irtysh river basin. Integral inventory of radionuclides in the main components of the river ecosystems is calculated. The estimated annual discharge of radionuclides from the Vandras river to the Great Salym river is given. The effect of the removal of man-made radionuclides in the Samson, Lev, Vandras rivers on radioactive contamination of the Ob-Irtysh river system is shown in comparison with the Techa river, that also belongs to the Ob-Irtysh river basin. Despite the presence of an additional radioactive contamination of the Samson floodplain, the transfer of radioactive substances in the Samson, Lev, Vandras rivers has a much smaller impact on the contamination of the Ob-Irtysh river system, compared to the Techa river, prone to a large-scale radioactive contamination. PMID:27534071

  14. Songbird use of floodplain and upland forests along the Upper Mississippi River corridor during spring migration

    USGS Publications Warehouse

    Kirsch, Eileen M.; Heglund, Patricia J.; Gray, Brian R.; Mckann, Patrick

    2013-01-01

    The Upper Mississippi River is thought to provide important stopover habitat for migrating landbirds because of its north-south orientation and floodplain forests. The river flows through the Driftless Area of southwestern Wisconsin and southeastern Minnesota where forests are plentiful, yet forests of the floodplain and Driftless Area uplands differ greatly in landscape setting, tree species composition, and topography. We compared landbird assemblages in these upland and floodplain forests over three springs, 2005–2007, using line-transect surveys at randomly selected areas in and within 16 km of the floodplain. We found more species of both transient and locally breeding migrants per survey in floodplain than in upland forest. Detections of transient neotropical migrants did not differ statistically by habitat. Detections of locally breeding neotropical and temperate-zone migrants and transient temperate-zone migrants were greater in floodplain than in upland forest. Between floodplain and upland forest, assemblages of locally breeding species, including neotropical and temperate-zone migrants (of which some individuals were in transit), differed substantially, but assemblages of transients (including both neotropical and temperate-zone migrants) did not differ as much. Only two species of transient migrants had clear affinities for floodplain forest, and none had an affinity for upland forest, whereas most locally breeding migrants had an affinity for either upland or floodplain forest. Within each spring, however, detections of transient neotropical migrants shifted from being greater in floodplain to greater in upland forests. This intraseasonal shift may be related to the phenology of certain tree species.

  15. Synchronous cycling of Ichthyophoniasis with Chinook salmon density revealed during the annual Yukon River spawning migration

    USGS Publications Warehouse

    Zuray, Stanley; Kocan, Richard; Hershberger, Paul

    2012-01-01

    Populations of Chinook salmon Oncorhynchus tshawytscha in the Yukon River declined by more than 57% between 2003 and 2010, probably the result of a combination of anthropogenic and environmental factors. One possible contributor to this decline is Ichthyophonus, a mesomycetozoan parasite that has previously been implicated in significant losses of fish, including Chinook salmon. A multiyear epidemiological study of ichthyophoniasis in the Yukon River revealed that disease prevalence and Chinook salmon population abundance increased and decreased simultaneously (i.e., were concordant) from 1999 to 2010. The two values rose and fell synchronously 91% of the time for female Chinook salmon and 82% of the time for males; however, there was no significant correlation between Ichthyophonus prevalence and population abundance. This synchronicity might be explained by a single factor, such as a prey item that is critical to Chinook salmon survival as well as a source of Ichthyophonus infection. The host–parasite relationship between Ichthyophonus and migrating Chinook salmon from 2004 to 2010 was similar to that reported for the previous 5 years. During 2004–2010, overall disease prevalence was significantly higher among females (21%) than among males (8%), increased linearly with fish length for both males and females, and increased in both sexes as the fish progressed upriver. These regularly occurring features of host–parasite dynamics confirm a stable base of transmission for Ichthyophonus. However, from 2003 to 2010, disease prevalence decreased from 30% to just 8% in males and from 45% to 9% in females, paralleling a similar decline in Chinook salmon abundance during the same period. These findings may help clarify questions regarding the complex host–parasite dynamics that occur in marine species such as herrings Clupea spp., which have less well-defined population structures.

  16. Meandering instability of a viscous thread

    NASA Astrophysics Data System (ADS)

    Morris, Stephen W.; Dawes, Jonathan H. P.; Ribe, Neil M.; Lister, John R.

    2008-06-01

    A viscous thread falling from a nozzle onto a surface exhibits the famous rope-coiling effect, in which the thread buckles to form loops. If the surface is replaced by a belt moving with speed U , the rotational symmetry of the buckling instability is broken and a wealth of interesting states are observed [see S. Chiu-Webster and J. R. Lister, J. Fluid Mech. 569, 89 (2006)]. We experimentally studied this “fluid-mechanical sewing machine” in a more precise apparatus. As U is reduced, the steady catenary thread bifurcates into a meandering state in which the thread displacements are only transverse to the motion of the belt. We measured the amplitude and frequency ω of the meandering close to the bifurcation. For smaller U , single-frequency meandering bifurcates to a two-frequency “figure-8” state, which contains a significant 2ω component and parallel as well as transverse displacements. This eventually reverts to single-frequency coiling at still smaller U . More complex, highly hysteretic states with additional frequencies are observed for larger nozzle heights. We propose to understand this zoology in terms of the generic amplitude equations appropriate for resonant interactions between two oscillatory modes with frequencies ω and 2ω . The form of the amplitude equations captures both the axisymmetry of the U=0 coiling state and the symmetry-breaking effects induced by the moving belt.

  17. Numerically Simulating the Hydrodynamic and Water Quality Environment for Migrating Salmon in the Lower Snake River

    SciTech Connect

    Cook, Chris B.; Richmond, Marshall C.; Coleman, Andre M.; Rakowski, Cynthia L.; Titzler, P. Scott; Bleich, Matthew D.

    2003-06-10

    Summer temperatures in the Lower Snake River can be altered by releasing cold waters that originate from deep depths within Dworshak Reservoir. These cold releases are used to lower temperatures in the Clearwater and Lower Snake Rivers, and improve hydrodynamic and water quality conditions for migrating aquatic species. This project monitored the complex three-dimensional hydrodynamic and thermal conditions at the confluence of the Clearwater and Snake Rivers and the processes that led to stratification of Lower Granite Reservoir (LGR) during the late spring, summer, and fall of 2002. Hydrodynamic, water quality, and meteorological conditions around the reservoir were monitored at frequent intervals, and this effort is currently continuing in 2003. Monitoring of the reservoir is a multi-year endeavor, and this report spans only the first year of data collection. In addition to monitoring the LGR environment, a three-dimensional hydrodynamic and water quality model has also been applied. This model uses collected field data as boundary conditions and has been applied to the entire 2002 field season. Numerous data collection sites were within the model domain and serve as both calibration and validation locations for the numerical model. Errors between observed and simulated data vary in magnitude from location to location and from one time to another. Generally, errors are small and within expected ranges, although model parameters may be improved in the future to minimize differences between observed and simulated values as additional 2003 field data become available. A two-dimensional laterally-averaged hydrodynamic and water quality model was applied to the three reservoirs downstream of LGR (the pools behind Little Goose, Lower Monumental, and Ice Harbor Dams). A two-dimensional model is appropriate for these reservoirs because observed lateral thermal variations during summer and fall 2002 were almost negligible, however vertical thermal variations were quite

  18. Migration and winter distributions of canvasbacks staging on the Upper Mississippi River

    USGS Publications Warehouse

    Serie, J.R.; Trauger, D.L.; Sharp, D.E.

    1983-01-01

    Fall and winter distribution patterns of canvasbacks (Aythya valisineria) staging on the upper Mississippi River near LaCrosse, Wisconsin (navigational Pools 7 and 8) and Keokuk, Iowa (Pool 19) were studied during 1973-77. Sightings and recoveries obtained from 1,488 color-marked males during 1973-75 and 3,789 banded males and females during 1973-77 suggested 2 principal migration corridors: 1 extending eastward from Pools 7 and 8 to the eastern Great Lakes and southeast to the Mid-Atlantic Region and another southward from Pools 7 and 8 to the lower Mississippi Valley, Gulf Coast, and east Texas regions. These discrete populations stage concurrently on Pools 7 and 8 during the fall, but winter in different areas of the Atlantic, Mississippi, and Central flyways. Populations staging on Pool 19 were not discrete from those staging on Pools 7 and 8. A continual turnover of birds passing through these staging areas was indicated. Canvasbacks wintering in the Mississippi and Central flyways were widely dispersed among a variety of habitats, whereas canvasbacks wintering in the Atlantic Flyway were concentrated in a few traditional habitats. Canvasbacks exhibited strong fidelity to wintering areas. Distribution patterns and population attributes of canvasbacks during fall and winter may be explained by the predictability of natural foods and their ability to exploit these foods.

  19. The persistence and characteristics of Chinook salmon migrations to the Upper Klamath River prior to exclusion by dams

    USGS Publications Warehouse

    Hamilton, John B; Rondorf, Dennis W.; Tinniswood, William; Leary, Ryan J; Mayer, Tim; Gavette, Charleen; Casal, Lynne A.

    2016-01-01

    In this research article, John Hamilton and his co-authors present extensive new research and information gathered since a 2005 publication on the historical evidence of anadromomous fish distribution in the Upper Klamath River watershed. Using historical accounts from early explorers and ethnographers to early-twentieth-century photographs, newspaper accounts, and government reports, the authors provide a more complete record of past salmon migrations. The updated record “substantiate[s] the historical persistence of salmon, their migration characteristics, and the broad population baseline that will be key to future commercial, recreational, and Tribal fisheries in the Klamath River and beyond.” During a time when salmon restoration plans are being considered in the region, the historical record can serve as guidance to once again establish diverse and thriving populations.

  20. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Juveniles, 2003-2004 Annual Report.

    SciTech Connect

    Achord, Stephen; Hodge, Jacob M.; Sandford, Benjamin P.

    2005-06-01

    This report provides information on PIT-tagging of wild Chinook salmon parr in Idaho in 2003 and the subsequent monitoring of these fish and similarly tagged fish from Oregon. We report estimated parr-to-smolt survival and arrival timing of these fish at Lower Granite Dam, as well as interrogation data collected at several other sites throughout the Snake and Columbia River system. This research continues studies that began under Bonneville Power Administration (BPA) funding in 1991. Results from previous study years were reported by Achord et al. (1994; 1995a,b; 1996a; 1997; 1998; 2000; 2001a,b; 2002, 2003, 2004). Goals of this ongoing study are: (1) Characterize the migration timing and estimate parr-to-smolt survival of different stocks of wild Snake River spring/summer Chinook salmon smolts at Lower Granite Dam. (2) Determine whether consistent migration patterns are apparent. (3) Determine what environmental factors influence migration patterns. (4) Characterize the migration behavior and estimate survival of different wild juvenile fish stocks as they emigrate from their natal rearing areas. This study provides critical information for recovery planning, and ultimately recovery for these ESA-listed wild fish stocks. In 2003-2004, we also continued to measure water temperature, dissolved oxygen, specific conductance, turbidity, water depth, and pH at five monitoring stations in the Salmon River Basin, Idaho for the Baseline Environmental Monitoring Program. These data, along with parr/smolt migration, survival, and timing data, will help to discern patterns or characteristic relationships between fish movement/survival and environmental factors.

  1. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 2001-2002 Annual Report.

    SciTech Connect

    Achond, Stephen; Hockersmith, Eric E.; Sandford, Benjamin P.

    2003-07-01

    This report details the 2002 results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends in the cumulative data collected for this project from Oregon and Idaho streams since 1989. The project was initiated after detection data from passive-integrated-transponder tags (PIT tags) had shown distinct differences in migration patterns between wild and hatchery fish for three consecutive years. National Marine Fisheries Service (NMFS) investigators first observed these differences in 1989. The data originated from tagging and interrogation operations begun in 1988 to evaluate smolt transportation for the U.S. Army Corps of Engineers. In 1991, the Bonneville Power Administration began a cooperative effort with NMFS to expand tagging and interrogation of wild fish. Project goals were to characterize the outmigration timing of these fish, to determine whether consistent migration patterns would emerge, and to investigate the influence of environmental factors on the timing and distribution of these migrations. In 1992, the Oregon Department of Fish and Wildlife (ODFW) began an independent program of PIT tagging wild chinook salmon parr in the Grande Ronde and Imnaha River Basins in northeast Oregon. Since then, ODFW has reported all tagging, detection, and timing information on fish from these streams. However, with ODFW concurrence, NMFS will continue to report arrival timing of these fish at Lower Granite Dam.

  2. Hydraulic Characteristics of the Lower Snake River during Periods of Juvenile Fall Chinook Salmon Migration, 2002-2006 Final Report.

    SciTech Connect

    Cook, C.; Dibrani, B.; Richmond, M.; Bleich, M.; Titzler, P..; Fu, T.

    2006-01-01

    This report documents a four-year study to assess hydraulic conditions in the lower Snake River. The work was conducted for the Bonneville Power Administration, U.S. Department of Energy, by the Pacific Northwest National Laboratory. Cold water released from the Dworshak Reservoir hypolimnion during mid- to late-summer months cools the Clearwater River far below equilibrium temperature. The volume of released cold water augments the Clearwater River, and the combined total discharge is on the order of the Snake River discharge when the two rivers meet at their confluence near the upstream edge of Lower Granite Reservoir. With typical temperature differences between the Clearwater and Snake rivers of 10 C or more during July and August, the density difference between the two rivers during summer flow augmentation periods is sufficient to stratify Lower Granite Reservoir as well as the other three reservoirs downstream. Because cooling of the river is desirable for migrating juvenile fall Chinook salmon (Oncorhynchus tshawytscha) during this same time period, the amount of mixing and cold water entrained into Lower Granite Reservoir's epilimnion at the Clearwater/Snake River confluence is of key biological importance. Data collected during this project indicates the three reservoirs downstream of Lower Granite also stratify as direct result of flow augmentation from Dworshak Reservoir. These four reservoirs are also heavily influenced by wind forcing at the water's surface and during periods of low river discharge often behave like a two-layer lake. During these periods of stratification, lower river discharge, and wind forcing, the water in the upper layer of the reservoir is held in place or moves slightly upstream. This upper layer is also exposed to surface heating and may warm up to temperatures close to equilibrium temperature. The thickness (depth) of this upper warm layer and its direction of travel may be of key biological importance to juvenile fall Chinook

  3. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Juveniles, 2007-2008

    SciTech Connect

    Achord, Stephen; Sandford, Benjamin P.; Hockersmith, Eric E.

    2009-07-09

    This report provides results from an ongoing project to monitor the migration behavior and survival of wild juvenile spring/summer Chinook salmon in the Snake River Basin. Data reported is from detections of PIT tagged fish during late summer 2007 through mid-2008. Fish were tagged in summer 2007 by the National Marine Fisheries Service (NMFS) in Idaho and by the Oregon Department of Fish and Wildlife (ODFW) in Oregon. Our analyses include migration behavior and estimated survival of fish at instream PIT-tag monitors and arrival timing and estimated survival to Lower Granite Dam. Principal results from tagging and interrogation during 2007-2008 are: (1) In July and August 2007, we PIT tagged and released 7,390 wild Chinook salmon parr in 12 Idaho streams or sample areas. (2) Overall observed mortality from collection, handling, tagging, and after a 24-hour holding period was 1.4%. (3) Of the 2,524 Chinook salmon parr PIT tagged and released in Valley Creek in summer 2007, 218 (8.6%) were detected at two instream PIT-tag monitoring systems in lower Valley Creek from late summer 2007 to the following spring 2008. Of these, 71.6% were detected in late summer/fall, 11.9% in winter, and 16.5% in spring. Estimated parr-to-smolt survival to Lower Granite Dam was 15.5% for the late summer/fall group, 48.0% for the winter group, and 58.5% for the spring group. Based on detections at downstream dams, the overall efficiency of VC1 (upper) or VC2 (lower) Valley Creek monitors for detecting these fish was 21.1%. Using this VC1 or VC2 efficiency, an estimated 40.8% of all summer-tagged parr survived to move out of Valley Creek, and their estimated survival from that point to Lower Granite Dam was 26.5%. Overall estimated parr-to-smolt survival for all summer-tagged parr from this stream at the dam was 12.1%. Development and improvement of instream PIT-tag monitoring systems continued throughout 2007 and 2008. (4) Testing of PIT-tag antennas in lower Big Creek during 2007

  4. Emergence of river dynamics through changing vegetation patterns

    NASA Astrophysics Data System (ADS)

    van Oorschot, Mijke; Kleinhans, Maarten; Middelkoop, Hans; Geerling, Gertjan

    2016-04-01

    Riparian vegetation interacts with morphodynamic processes in rivers to create distinct habitat mosaics supporting a large biodiversity. The aim of our work is to quantitatively investigate the emergent patterns in vegetation and river morphology at the river reach scale by dynamically modelling the processes and their interactions. Here, we coupled an advanced morphodynamic model to a novel dynamic riparian vegetation model to study the interaction between vegetation and morphodynamics. Vegetation colonizes bare substrate within the seed dispersal window, passes several growth stages with different properties and can die through flooding, desiccation, uprooting, scour or burial. We have compared river morphology and vegetation patterns of scenarios without vegetation, with static vegetation that does not grow or die and several dynamic vegetation scenarios with a range of vegetation strategies and eco-engineering properties. Results show that dynamic vegetation has a decreased lateral migration of meander bends and maintains its active meandering behavior as opposed to the scenarios without vegetation and with static vegetation. Also the patterns in vegetation and fluvial morphology and the vegetation age distribution mostly resemble the natural situation when compared to aerial photos of the study area. We find that river dynamics, specifically sinuosity and sediment transport, are very sensitive to vegetation properties that determine vegetation density, settlement location and survival. Future work will include the effects of invasive species, addition of silt and the effect of various river management strategies.

  5. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2008.

    SciTech Connect

    Faulkner, James R.; Smith, Steven G.; Muir, William D.

    2009-06-23

    In 2008, the National Marine Fisheries Service completed the sixteenth year of a study to estimate survival and travel time of juvenile salmonids Oncorhynchus spp. passing through dams and reservoirs on the Snake and Columbia Rivers. All estimates were derived from detections of fish tagged with passive integrated transponder (PIT) tags. We PIT tagged and released a total of 18,565 hatchery steelhead O. mykiss, 15,991 wild steelhead, and 9,714 wild yearling Chinook salmon O. tshawytscha at Lower Granite Dam in the Snake River. In addition, we utilized fish PIT tagged by other agencies at traps and hatcheries upstream from the hydropower system and at sites within the hydropower system in both the Snake and Columbia Rivers. These included 122,061 yearling Chinook salmon tagged at Lower Granite Dam for evaluation of latent mortality related to passage through Snake River dams. PIT-tagged smolts were detected at interrogation facilities at Lower Granite, Little Goose, Lower Monumental, Ice Harbor, McNary, John Day, and Bonneville Dams and in the PIT-tag detector trawl operated in the Columbia River estuary. Survival estimates were calculated using a statistical model for tag-recapture data from single release groups (the single-release model). Primary research objectives in 2008 were to: (1) estimate reach survival and travel time in the Snake and Columbia Rivers throughout the migration period of yearling Chinook salmon and steelhead, (2) evaluate relationships between survival estimates and migration conditions, and (3) evaluate the survival estimation models under prevailing conditions. This report provides reach survival and travel time estimates for 2008 for PIT-tagged yearling Chinook salmon (hatchery and wild), hatchery sockeye salmon O. nerka, hatchery coho salmon O. kisutch, and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Additional details on the methodology and statistical models used are provided in previous reports cited here. Survival

  6. The Sredne-Amursky basin: A migrating cretaceous depocenter for the Amur river, eastern Siberia

    SciTech Connect

    Light, M.; Maslanyj, M.; Davidson, K. )

    1993-09-01

    Recently acquired seismic, well, and regional geological data imply favorable conditions for the accumulation of oil and gas in the 20,000 km[sup 2] Sredne-Amursky basin. Major graben and northeast-trending sinistral wrench-fault systems are recognized in the basin. Lower and Upper Cretaceous sediments are up to 9000 and 3000 m thick, respectively. Paleogeographic reconstructions imply that during the Late Triassic-Early Cretaceous the Sredne-Amursky basin was part of a narrow marine embayment (back-arc basin), which was open to the north. During the Cretaceous, the region was part of a foreland basin complicated by strike-slip, which produced subsidence related to transtension during oblique collision of the Sikhote-Alin arc with Eurasian margin. Contemporaneous uplift also related to this collision migrated from south to north and may have sourced northward-directed deltas and alluvial fans, which fed northward into the closing back-arc basin between 130 and 85 Ma. The progradational clastic succession of the Berriasian-Albian and the Late Cretaceous fluvial, brackish water and paralic sediments within the basin may be analogous to the highly productive late Tertiary clastics of the Amur River delta in the northeast Sakhalin basin. Cretaceous-Tertiary lacustrine-deltaic sapropelic shales provide significant source and seal potential and potential reservoirs occur in the Cretaceous and Tertiary. Structural plays were developed during Cretaceous rifting and subsequent strike-slip deformation. If the full hydrocarbon potential of the Sredne-Amursky basin is to be realized, the regional appraisal suggests that exploration should be focused toward the identification of plays related to prograding Cretaceous deltaic depositional systems.

  7. Foraging ecology of fall-migrating shorebirds in the Illinois River valley.

    PubMed

    Smith, Randolph V; Stafford, Joshua D; Yetter, Aaron P; Horath, Michelle M; Hine, Christopher S; Hoover, Jeffery P

    2012-01-01

    Populations of many shorebird species appear to be declining in North America, and food resources at stopover habitats may limit migratory bird populations. We investigated body condition of, and foraging habitat and diet selection by 4 species of shorebirds in the central Illinois River valley during fall migrations 2007 and 2008 (Killdeer [Charadrius vociferus], Least Sandpiper [Calidris minutilla], Pectoral Sandpiper [Calidris melanotos], and Lesser Yellowlegs [Tringa flavipes]). All species except Killdeer were in good to excellent condition, based on size-corrected body mass and fat scores. Shorebird diets were dominated by invertebrate taxa from Orders Diptera and Coleoptera. Additionally, Isopoda, Hemiptera, Hirudinea, Nematoda, and Cyprinodontiformes contribution to diets varied by shorebird species and year. We evaluated diet and foraging habitat selection by comparing aggregate percent dry mass of food items in shorebird diets and core samples from foraging substrates. Invertebrate abundances at shorebird collection sites and random sites were generally similar, indicating that birds did not select foraging patches within wetlands based on invertebrate abundance. Conversely, we found considerable evidence for selection of some diet items within particular foraging sites, and consistent avoidance of Oligochaeta. We suspect the diet selectivity we observed was a function of overall invertebrate biomass (51.2 ± 4.4 [SE] kg/ha; dry mass) at our study sites, which was greater than estimates reported in most other food selection studies. Diet selectivity in shorebirds may follow tenants of optimal foraging theory; that is, at low food abundances shorebirds forage opportunistically, with the likelihood of selectivity increasing as food availability increases. Nonetheless, relationships between the abundance, availability, and consumption of Oligochaetes for and by waterbirds should be the focus of future research, because estimates of foraging carrying capacity

  8. Foraging ecology of fall-migrating shorebirds in the Illinois River valley.

    PubMed

    Smith, Randolph V; Stafford, Joshua D; Yetter, Aaron P; Horath, Michelle M; Hine, Christopher S; Hoover, Jeffery P

    2012-01-01

    Populations of many shorebird species appear to be declining in North America, and food resources at stopover habitats may limit migratory bird populations. We investigated body condition of, and foraging habitat and diet selection by 4 species of shorebirds in the central Illinois River valley during fall migrations 2007 and 2008 (Killdeer [Charadrius vociferus], Least Sandpiper [Calidris minutilla], Pectoral Sandpiper [Calidris melanotos], and Lesser Yellowlegs [Tringa flavipes]). All species except Killdeer were in good to excellent condition, based on size-corrected body mass and fat scores. Shorebird diets were dominated by invertebrate taxa from Orders Diptera and Coleoptera. Additionally, Isopoda, Hemiptera, Hirudinea, Nematoda, and Cyprinodontiformes contribution to diets varied by shorebird species and year. We evaluated diet and foraging habitat selection by comparing aggregate percent dry mass of food items in shorebird diets and core samples from foraging substrates. Invertebrate abundances at shorebird collection sites and random sites were generally similar, indicating that birds did not select foraging patches within wetlands based on invertebrate abundance. Conversely, we found considerable evidence for selection of some diet items within particular foraging sites, and consistent avoidance of Oligochaeta. We suspect the diet selectivity we observed was a function of overall invertebrate biomass (51.2 ± 4.4 [SE] kg/ha; dry mass) at our study sites, which was greater than estimates reported in most other food selection studies. Diet selectivity in shorebirds may follow tenants of optimal foraging theory; that is, at low food abundances shorebirds forage opportunistically, with the likelihood of selectivity increasing as food availability increases. Nonetheless, relationships between the abundance, availability, and consumption of Oligochaetes for and by waterbirds should be the focus of future research, because estimates of foraging carrying capacity

  9. Foraging Ecology of Fall-Migrating Shorebirds in the Illinois River Valley

    PubMed Central

    Smith, Randolph V.; Stafford, Joshua D.; Yetter, Aaron P.; Horath, Michelle M.; Hine, Christopher S.; Hoover, Jeffery P.

    2012-01-01

    Populations of many shorebird species appear to be declining in North America, and food resources at stopover habitats may limit migratory bird populations. We investigated body condition of, and foraging habitat and diet selection by 4 species of shorebirds in the central Illinois River valley during fall migrations 2007 and 2008 (Killdeer [Charadrius vociferus], Least Sandpiper [Calidris minutilla], Pectoral Sandpiper [Calidris melanotos], and Lesser Yellowlegs [Tringa flavipes]). All species except Killdeer were in good to excellent condition, based on size-corrected body mass and fat scores. Shorebird diets were dominated by invertebrate taxa from Orders Diptera and Coleoptera. Additionally, Isopoda, Hemiptera, Hirudinea, Nematoda, and Cyprinodontiformes contribution to diets varied by shorebird species and year. We evaluated diet and foraging habitat selection by comparing aggregate percent dry mass of food items in shorebird diets and core samples from foraging substrates. Invertebrate abundances at shorebird collection sites and random sites were generally similar, indicating that birds did not select foraging patches within wetlands based on invertebrate abundance. Conversely, we found considerable evidence for selection of some diet items within particular foraging sites, and consistent avoidance of Oligochaeta. We suspect the diet selectivity we observed was a function of overall invertebrate biomass (51.2±4.4 [SE] kg/ha; dry mass) at our study sites, which was greater than estimates reported in most other food selection studies. Diet selectivity in shorebirds may follow tenants of optimal foraging theory; that is, at low food abundances shorebirds forage opportunistically, with the likelihood of selectivity increasing as food availability increases. Nonetheless, relationships between the abundance, availability, and consumption of Oligochaetes for and by waterbirds should be the focus of future research, because estimates of foraging carrying capacity

  10. Origins and impacts of mesoscale meanders in the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Elipot, S.; Beal, L. M.

    2014-12-01

    The Agulhas Current (AC) is the western boundary current of the South Indian subtropical gyre and is also the pathway for the inter-basin exchange of water, heat and salt between the Indian Ocean and the Atlantic Ocean, and thus a crucial part of the global overturning circulation of the world ocean. The AC, which otherwise flows stably along the coast of South Africa, undergoes dramatic offshore excursions from its mean path, forming large mesoscale solitary meanders propagating downstream and potentially linked to the leakage of Indian Ocean waters to the South Atlantic. These irregular meander events have been referred to as Natal Pulses.Here we present new observations and analyses of Agulhas meanders using full-depth velocity mooring observations from the Agulhas Current Time series experiment (ACT). Detailed analyses of the in-situ velocity reveal important differences between the behavior of the flow during solitary meander events and during meander events of smaller amplitude. During solitary meanders, an onshore cyclonic circulation and an offshore anticyclonic circulation act in concert to displace the jet offshore, leading to sudden and strong positive conversion of kinetic energy of the mean flow to the meander. In contrast, smaller amplitude meanderings are principally represented by a single cyclonic circulation spanning the entire jet that acts to displace the jet without significantly extracting kinetic energy from the mean flow. Solitary meander events can be traced upstream using satellite altimetry and linked to either Mozambique Channel eddies or Madagascar dipoles, the latter possibly part of a basin-wide pattern of propagating sea level anomalies consistent with Rossby wave dynamics. However, only a small number of these anomalies lead to solitary meanders. Altimetric observations suggest 1.5 meanders per year and show that the two-year period during ACT when no events were observed is unprecedented in the 20-year satellite record.

  11. Including independent estimates and uncertainty to quantify total abundance of fish migrating in a large river system: walleye (Sander vitreus) in the Maumee River, Ohio

    USGS Publications Warehouse

    Pritt, Jeremy J.; DuFour, Mark R.; Mayer, Christine M.; Kocovsky, Patrick M.; Tyson, Jeffrey T.; Weimer, Eric J.; Vandergoot, Christopher S.

    2013-01-01

    Walleye (Sander vitreus) in Lake Erie is a valuable and migratory species that spawns in tributaries. We used hydroacoustic sampling, gill net sampling, and Bayesian state-space modeling to estimate the spawning stock abundance, characterize size and sex structure, and explore environmental factors cuing migration of walleye in the Maumee River for 2011 and 2012. We estimated the spawning stock abundance to be between 431,000 and 1,446,000 individuals in 2011 and between 386,400 and 857,200 individuals in 2012 (95% Bayesian credible intervals). A back-calculation from a concurrent larval fish study produced an estimate of 78,000 to 237,000 spawners for 2011. The sex ratio was skewed towards males early in the spawning season but approached 1:1 later, and larger individuals entered the river earlier in the season than smaller individuals. Walleye migration was greater during low river discharge and intermediate temperatures. Our approach to estimating absolute abundance and uncertainty as well as characterization of the spawning stock could improve assessment and management of this species, and our methodology is applicable to other diadromous populations.

  12. Stock-specific migration timing of adult spring-summer Chinook salmon in the Columbia River basin

    USGS Publications Warehouse

    Keefer, M.L.; Peery, C.A.; Jepson, M.A.; Tolotti, K.R.; Bjornn, T.C.; Stuehrenberg, L.C.

    2004-01-01

    An understanding of the migration timing patterns of Pacific salmon Oncorhynchus spp. and steelhead O. mykiss is important for managing complex mixed-stock fisheries and preserving genetic and life history diversity. We examined adult return timing for 3,317 radio-tagged fish from 38 stocks of Columbia River basin spring-summer Chinook salmon O. tshawytscha over 5 years. Stock composition varied widely within and between years depending on the strength of influential populations. Most individual stocks migrated at similar times each year relative to overall runs, supporting the hypotheses that run timing is predictable, is at least partially due to genetic adaptation, and can be used to differentiate between some conspecific populations. Arrival timing of both aggregated radio-tagged stocks and annual runs was strongly correlated with river discharge; stocks arrived earlier at Bonneville Dam and at upstream dams in years with low discharge. Migration timing analyses identified many between-stock and between-year differences in anadromous salmonid return behavior and should and managers interested in protection and recovery of evolutionary significant populations.

  13. The effects of river impoundment and hatchery rearing on the migration behavior of juvenile steelhead in the Lower Snake River, Washington

    USGS Publications Warehouse

    Plumb, J.M.; Perry, R.W.; Adams, N.S.; Rondorf, D.W.

    2006-01-01

    We used radiotelemetry to monitor the migration behavior of juvenile hatchery and wild steelhead Oncorhynchus mykiss as they migrated through Lower Granite Reservoir and Dam on the lower Snake River, Washington. From 1996 to 2001, we surgically implanted radio transmitters in 1,540 hatchery steelhead and 1,346 wild steelhead. For analysis, we used the inverse Gaussian distribution to describe travel time distributions for cohorts (>50 fish) of juvenile steelhead as they migrated downriver. Mean travel rates were significantly related to reach- and discharge-specific water velocities. Also, mean travel rates near the dam were slower for a given range of water velocities than were mean travel rates through the reservoir, indicating that the presence of the dam caused delay to juvenile steelhead over and above the effect of water velocity. Hatchery steelhead took about twice as long as wild steelhead to pass the dam as a result of the higher proportions of hatchery steelhead traveling upriver from the dam. Because upriver travel and the resulting migration delay might decrease survival, it is possible that hatchery steelhead survive at lower rates than wild steelhead. Our analysis identified a discharge threshold (???2,400 m3/s) below which travel time and the percentage of fish traveling upriver from the dam increased rapidly, providing support for the use of minimum flow targets to mitigate for fish delay and possibly enhance juvenile steelhead survival.

  14. Genetics, recruitment, and migration patterns of Arctic Cisco (Coregonus autumnalis) in the Colville River, Alaska and Mackenzie River, Canada

    USGS Publications Warehouse

    Zimmerman, Christian E.; Ramey, Andy M.; Turner, S.; Mueter, Franz J.; Murphy, S.; Nielsen, Jennifer L.

    2013-01-01

    Arctic cisco Coregonus autumnalis have a complex anadromous life history, many aspects of which remain poorly understood. Some life history traits of Arctic cisco from the Colville River, Alaska, and Mackenzie River basin, Canada, were investigated using molecular genetics, harvest data, and otolith microchemistry. The Mackenzie hypothesis, which suggests that Arctic cisco found in Alaskan waters originate from the Mackenzie River system, was tested using 11 microsatellite loci and a single mitochondrial DNA gene. No genetic differentiation was found among sample collections from the Colville River and the Mackenzie River system using molecular markers (P > 0.19 in all comparisons). Model-based clustering methods also supported genetic admixture between sample collections from the Colville River and Mackenzie River basin. A reanalysis of recruitment patterns to Alaska, which included data from recent warm periods and suspected changes in atmospheric circulation patterns, still finds that recruitment is correlated to wind conditions. Otolith microchemistry (Sr/Ca ratios) confirmed repeated, annual movements of Arctic cisco between low-salinity habitats in winter and marine waters in summer.

  15. River mobility in a permafrost dominated floodplain

    NASA Astrophysics Data System (ADS)

    Rowland, J.; Wilson, C.; Brumby, S.; Pope, P.

    2009-04-01

    Along arctic coastlines, recent studies have attributed dramatic increases in the rates of shoreline erosion to global climate change and permafrost degradation. While across much of the arctic, changes in the size and number of lakes have been interpreted as the result of permafrost degradation altering surface water dynamics. The potential influence of climate change and permafrost thawing on the mobility and form of arctic rivers, however, has been relatively unexplored to date. In rivers located within permafrost, some to potentially most, of the cohesive bank strength may be derived from frozen materials. It is likely that, as permafrost thaws, river bank erosion may increase, in turn influencing both migration rates and channel planform. Using automated feature extraction software (GeniePro), we quantified the of the mobility of a 200 km reach of the Yukon River through the Yukon Flats region located just north of Fairbanks, Alaska, USA. The Yukon Flats is an area of comprised of both continuous and discontinuous permafrost. Based on both changes in lake distributions and wintertime river base flows, it has been suggested that permafrost in this area has been experiencing recent thawing. In this reach, the Yukon River transitions from a 2 km wide braided channel to a multi-thread meandering channel where individual threads are approximately 1 km wide and the floodplain preserves prior meander cutoffs and oxbow lakes. Preliminary results from thirty years of LANDSAT imagery shows a surprising stability of channel location (at the image resolution of 30m/pixel) given the channel form. Within the braid-belt there is localized relocation of channel threads and mid-channel islands, though along much of the reach, the change in the location of channels banks is close to the resolution of the imagery. At the most active bends, bank migration rates range from 0.007 to 0.02 channel widths per year. These rates are comparable to system wide average rates observed on

  16. Comparative ontogenetic behavior and migration of kaluga, Huso dauricus, and Amur sturgeon, Acipenser schrenckii, from the Amur River

    USGS Publications Warehouse

    Zhuang, P.; Kynard, B.; Zhang, L.; Zhang, T.; Cao, W.

    2003-01-01

    We conducted laboratory experiments with kaluga, Huso dauricus, and Amur sturgeon, Acipenser schrenckii, to develop a conceptual model of early behavior. We daily observed embryos (first life phase after hatching) and larvae (period initiating exogenous feeding) to day-30 (late larvae) for preference of bright habitat and cover, swimming distance above the bottom, up- and downstream movement, and diel activity. Day-0 embryos of both species strongly preferred bright, open habitat and initiated a strong, downstream migration that lasted 4 days (3 day peak) for kaluga and 3 days (2 day peak) for Amur sturgeon. Kaluga migrants swam far above the bottom (150 cm) on only 1 day and moved day and night; Amur sturgeon migrants swam far above the bottom (median 130 cm) during 3 days and were more nocturnal than kaluga. Post-migrant embryos of both species moved day and night, but Amur sturgeon used dark, cover habitat and swam closer to the bottom than kaluga. The larva period of both species began on day 7 (cumulative temperature degree-days, 192.0 for kaluga and 171.5 for Amur sturgeon). Larvae of both species preferred open habitat. Kaluga larvae strongly preferred bright habitat, initially swam far above the bottom (median 50-105 cm), and migrated downstream at night during days 10-16 (7-day migration). Amur sturgeon larvae strongly avoided illumination, had a mixed response to white substrate, swam 20-30 cm above the bottom during most days, and during days 12-34 (most of the larva period) moved downstream mostly at night (23-day migration). The embryo-larva migration style of the two species likely shows convergence of non-related species for a common style in response to environmental selection in the Amur River. The embryo-larva migration style of Amur sturgeon is unique among Acipenser yet studied.

  17. Streamwise vortex meander in a plane mixing layer

    NASA Technical Reports Server (NTRS)

    Leboeuf, Richard L.; Mehta, Rabindra D.

    1993-01-01

    The present experimental study was conducted in order to determine the existence of streamwise vortex meander in a mixing layer, and if present, its significance on the measured properties. The dependence of the velocity cross-correlation on the fixed probe location was shown to be a good indicator of the stationarity of the streamwise vortex location. The cross-correlation measurements obtained here indicate that spanwise meander is negligible, although transverse apparent meander (normal to the plane of the mixing layer) was indicated. The transverse meander, exemplified by the elliptical shape of the mean streamwise vorticity contours, was expected, since the streamwise vorticity in the braid region is essentially inclined, with respect to the streamwise direction. These conclusions were supported by results of estimated spanwise profiles of the transverse velocity component. The balance of evidence suggests that the measured mean streamwise vorticity decay is representative of the decay of the vorticity rather than an artifact of meander.

  18. Hydrodynamics and sediment transport in a meandering channel with a model axial-flow hydrokinetic turbine

    NASA Astrophysics Data System (ADS)

    Hill, Craig; Kozarek, Jessica; Sotiropoulos, Fotis; Guala, Michele

    2016-02-01

    An investigation into the interactions between a model axial-flow hydrokinetic turbine (rotor diameter, dT = 0.15 m) and the complex hydrodynamics and sediment transport processes within a meandering channel was carried out in the Outdoor StreamLab research facility at the University of Minnesota St. Anthony Falls Laboratory. This field-scale meandering stream with bulk flow and sediment discharge control provided a location for high spatiotemporally resolved measurements of bed and water surface elevations around the model turbine. The device was installed within an asymmetric, erodible channel cross section under migrating bed form and fixed outer bank conditions. A comparative analysis between velocity and topographic measurements, with and without the turbine installed, highlights the local and nonlocal features of the turbine-induced scour and deposition patterns. In particular, it shows how the cross-section geometry changes, how the bed form characteristics are altered, and how the mean flow field is distorted both upstream and downstream of the turbine. We further compare and discuss how current energy conversion deployments in meander regions would result in different interactions between the turbine operation and the local and nonlocal bathymetry compared to straight channels.

  19. Water velocity, turbulence, and migration rate of subyearling fall Chinook salmon in the free-flowing and impounded Snake River

    USGS Publications Warehouse

    2009-01-01

    We studied the migratory behavior of subyearling fall Chinook salmon Oncorhynchus tshawytscha in free-flowing and impounded reaches of the Snake River to evaluate the hypothesis that velocity and turbulence are the primary causal mechanisms of downstream migration. The hypothesis states that impoundment reduces velocity and turbulence and alters the migratory behavior of juvenile Chinook salmon as a result of their reduced perception of these cues. At a constant flow (m3 /s), both velocity (km/d) and turbulence (the SD of velocity) decreased from riverine to impounded habitat as cross-sectional areas increased. We found evidence for the hypothesis that subyearling Chinook salmon perceive velocity and turbulence cues and respond to these cues by varying their behavior. The percentage of the subyearlings that moved faster than the average current speed decreased as fish made the transition from riverine reaches with high velocities and turbulence to upper reservoir reaches with low velocities and turbulence but increased to riverine levels again as the fish moved further down in the reservoir, where velocity and turbulence remained low. The migration rate (km/d) decreased in accordance with longitudinal reductions in velocity and turbulence, as predicted by the hypothesis. The variation in migration rate was better explained by a repeatedmeasures regression model containing velocity (Akaike’s information criterion ¼ 1,769.0) than a model containing flow (2,232.6). We conclude that subyearling fall Chinook salmon respond to changes in water velocity and turbulence, which work together to affect the migration rate.

  20. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 2000-2001 Annual Report.

    SciTech Connect

    Achord, Stephen; Axel, Gordon A.; Hockersmith, Eric E.

    2002-07-01

    This report details the 2001 results from an ongoing project to monitor the migration behavior of wild spring/summer chinook salmon smolts in the Snake River Basin. The report also discusses trends in the cumulative data collected for this project from Oregon and Idaho streams since 1989. The project was initiated after detection data from passive-integrated-transponder tags (PIT tags) had shown distinct differences in migration patterns between wild and hatchery fish for three consecutive years. National Marine Fisheries Service (NMFS) investigators first observed these data in 1989. The data originated from tagging and interrogation operations begun in 1988 to evaluate smolt transportation for the U.S. Army Corps of Engineers.

  1. Fluvial changes of the Guadalquivir river during the Holocene in Córdoba (Southern Spain)

    NASA Astrophysics Data System (ADS)

    Uribelarrea, David; Benito, Gerardo

    2008-08-01

    Holocene fluvial changes of the Guadalquivir River at Córdoba City were studied with an emphasis on floodplain development, river migration rates, sedimentation rates and environmental history. During the Holocene, the Guadalquivir River has developed a large meander (El Arenal) with a general southwards lateral migration, undercutting Tertiary bedrock, and with a total incision of 9 m, which developed three alluvial surfaces: Fp1, Fp2 and Fp3. The oldest floodplain surface Fp1 (+ 7-9 m) was deposited during the early Holocene and reached its maximum extent around 1000 yr BP. The next floodplain surface Fp2 (+ 5 m) accumulated 500 to 1000 yr ago. Finally, the youngest floodplain surface (Fp3, + 1-2 m) was developed in the last 500 yr. Migration rates and direction changed from 690-480 m 2 yr - 1 in Fp1 (to the southeast), 2280 m 2 yr - 1 in Fp2 and 620 m 2 yr - 1 in Fp3 (to the west). The stratigraphical study of palaeomeanders and chute channel deposits show evidence of river position and dynamics through recent times: (1) "San Eduardo" was filled 4000 yr BP; (2) "Madre Vieja" has been active since 2100 yr BP to the present day; and (3) "El Cortijo" was formed and filled during historical times (the last 1000 yr). The chronology of the alluvial stratigraphy and fluvial dynamics are discussed within the context of historical hydrologic, climatic and anthropogenic changes. In addition, the geomorphological reconstruction of the riverine landscape in historical times provided some clue to the location of Medinat al-Zahira, a lost Muslim settlement built in the 10th century AD and believed to be situated at, or nearby, the Arenal meander. Paleogeographical analysis shows that the most suitable conditions for this medieval settlement were found on the northeast part of the Arenal meander.

  2. Migration depths of adult steelhead Oncorhynchus mykiss in relation to dissolved gas supersaturation in a regulated river system

    SciTech Connect

    Johnson, Eric L.; Clabough, Tami S.; Caudill, Christopher C.; keefer, matthew L.; Peery, Christopher A.; Richmond, Marshall C.

    2010-04-01

    Adult steelhead tagged with archival transmitters primarily migrated through a large river corridor at depths > 2 m, interspersed with frequent but short (< 5 min) periods closer to the surface. The recorded swimming depths and behaviours probably provided adequate hydrostatic compensation for the encountered supersaturated dissolved gas conditions and probably limited development of gas bubble disease (GBD). Results parallel those from a concurrent adult Chinook salmon study, except steelhead experienced greater seasonal variability and were more likely to have depth-uncompensated supersaturation exposure in some dam tailraces, perhaps explaining the higher incidence of GBD in this species.

  3. [Sources, Migration and Conversion of Dissolved Alkanes, Dissolved Fatty Acids in a Karst Underground River Water, in Chongqing Area].

    PubMed

    Liang, Zuo-bing; Sun, Yu-chuan; Wang, Zun-bo; Shi, Yang; Jiang, Ze-li; Zhang, Mei; Xie, Zheng-Lan; Liao, Yu

    2015-09-01

    Dissolved alkanes and dissolved fatty acids were collected from Qingmuguan underground river in July, October 2013. By gas chromatography-mass spectrometer (GC-MS), alkanes and fatty acids were quantitatively analyzed. The results showed that average contents of alkanes and fatty acids were 1 354 ng.L-1, 24203 ng.L-1 in July, and 667 ng.L-1, 2526 ng.L-1 in October respectively. With the increasing migration distance of dissolved alkanes and dissolved fatty acids in underground river, their contents decreased. Based on the molecular characteristic indices of alkanes, like CPI, OEP, Paq and R, dissolved alkanes were mainly originated from microorganisms in July, and aquatic plants in October. Saturated straight-chain fatty acid had the highest contents in all samples with the dominant peak in C16:0, combined with the characteristics of carbon peak, algae or bacteria might be the dominant source of dissolved fatty acids. PMID:26717680

  4. Migration depths of juvenile Chinook salmon and steelhead relative to total dissolved gas supersaturation in a Columbia River reservoir

    USGS Publications Warehouse

    Beeman, J.W.; Maule, A.G.

    2006-01-01

    The in situ depths of juvenile salmonids Oncorhynchus spp. were studied to determine whether hydrostatic compensation was sufficient to protect them from gas bubble disease (GBD) during exposure to total dissolved gas (TDG) supersaturation from a regional program of spill at dams meant to improve salmonid passage survival. Yearling Chinook salmon O. tshawytscha and juvenile steelhead O. mykiss implanted with pressure-sensing radio transmitters were monitored from boats while they were migrating between the tailrace of Ice Harbor Dam on the Snake River and the forebay of McNary Dam on the Columbia River during 1997-1999. The TDG generally decreased with distance from the tailrace of the dam and was within levels known to cause GBD signs and mortality in laboratory bioassays. Results of repeated-measures analysis of variance indicated that the mean depths of juvenile steelhead were similar throughout the study area, ranging from 2.0 m in the Snake River to 2.3 m near the McNary Dam forebay. The mean depths of yearling Chinook salmon generally increased with distance from Ice Harbor Dam, ranging from 1.5 m in the Snake River to 3.2 m near the forebay. Juvenile steelhead were deeper at night than during the day, and yearling Chinook salmon were deeper during the day than at night. The TDG level was a significant covariate in models of the migration depth and rates of each species, but no effect of fish size was detected. Hydrostatic compensation, along with short exposure times in the area of greatest TDG, reduced the effects of TDG exposure below those generally shown to elicit GBD signs or mortality. Based on these factors, our results indicate that the TDG limits of the regional spill program were safe for these juvenile salmonids.

  5. The Owens River as a tiltmeter for Long Valley caldera, California

    SciTech Connect

    Reid, J.B. Jr )

    1992-05-01

    In the lower 11 km of its course around the resurgent dome of Long Valley caldera, the Owens River displays two parallel meander belts, comparable in meander wavelength and amplitude but unequal in age, elevation, and discharge. It appears the two belts take turns carrying the river's flow depending on whether the dome is inflating or subsiding. The inboard belt, some 200-300 m closer to the dome and now 30-60 cm higher in elevation, contains an underfit stream and is now being abandoned. The outboard channel formed in a series of avulsions apparently induced by recent uplift of the dome. In the upper 4 km of the two-channel reach, avulsion occurred between 1856 and 1878 as inferred from the original US Coast and Geodetic Survey mapping the caldera. Avulsion had already occurred by 1856 in the lower 4 km of the river, suggesting a possible migration of the center of uplift through time. More ancient meander scars at the inboard and outboard limits of the floodplain imply additional earlier episodes of inflation and subsidence. Projection of surveyed topographic profiles across the river's floodplain to the center of the dome suggests that cumulative recent uplift is on the order of 15-35 m, or about 30-70 times greater than that measured for the caldera since 1979 (Castle et al. 1984). The duration of the era of subsidence can be estimated by comparing oxbow densities in the old and new meander belts in the upper two-channel reach; the data suggest that the dome may have been in subsidence for a period of at least 500 to 1,000 yr ending about 150 yr ago. No eruptions of the Long Valley volcanic system have accompanied these inflations and subsidings.

  6. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters. PMID:25189685

  7. Sulfate migration in a river affected by acid mine drainage from the Dabaoshan mining area, South China.

    PubMed

    Chen, Meiqin; Lu, Guining; Guo, Chuling; Yang, Chengfang; Wu, Jingxiong; Huang, Weilin; Yee, Nathan; Dang, Zhi

    2015-01-01

    Sulfate, a major component of acid mine drainage (AMD), its migration in an AMD-affected river which located at the Dabaoshan mine area of South China was investigated to pursue the remediation strategy. The existing factors of relatively low pH values of 2.8-3.9, high concentrations of SO4(2-) (∼1940 mg L(-1)) and Fe(3+) (∼112 mg L(-1)) facilitated the precipitation of schwertmannite (Fe8O8(OH)6SO4·nH2O) in the upstream river. Geochemical model calculations implied the river waters were supersaturated, creating the potential for precipitation of iron oxyhydroxides. These minerals evolved from schwertmannite to goethite with the increasing pH from 2.8 to 5.8 along the river. The concentration of heavy metals in river waters was great reduced as a result of precipitation effects. The large size of the exchangeable sulfate pool suggested that the sediments had a strong capacity to bind SO4(2-). The XRD results indicated that schwertmannite was the predominant form of sulfate-bearing mineral phases, which was likely to act as a major sulfate sink by incorporating water-borne sulfate into its internal structure and adsorbing it onto its surface. The small size of reduced sulfur pools and strong oxidative status in the surface sediments further showed that SO4(2-) shifting from water to sediment in form of sulfate reduction was not activated. In short, precipitation of sulfate-rich iron oxyhydroxides and subsequent SO4(2-) adsorption on these minerals as well as water dilution contributed to the attenuation of SO4(2-) along the river waters.

  8. Movements of adult chinook salmon during spawning migration in a metals-contaminated system, Coeur d'Alene River, Idaho

    USGS Publications Warehouse

    Goldstein, J.N.; Woodward, D.F.; Farag, A.M.

    1999-01-01

    Spawning migration of adult male chinook salmon Oncorhynchus tshawytscha was monitored by radio telemetry to determine their response to the presence of metals contamination in the South Fork of the Coeur d'Alene River, Idaho. The North Fork of the Coeur d'Alene River is relatively free of metals contamination and was used as a control. In all, 45 Chinook salmon were transported from their natal stream. Wolf Lodge Creek, tagged with radio transmitters, and released in the Coeur d'Alene River 2 km downstream of the confluence of the South Fork and the North Fork of the Coeur d'Alene River. Fixed telemetry receivers were used to monitor the upstream movement of the tagged chinook salmon through the confluence area for 3 weeks after release. During this period, general water quality and metals concentrations were monitored in the study area. Of the 23 chinook salmon observed to move upstream from the release site and through the confluence area, the majority (16 fish, 70%) moved up the North Fork, and only 7 fish (30%) moved up the South Fork, where greater metals concentrations were observed. Our results agree with laboratory findings and suggest that natural fish populations will avoid tributaries with high metals contamination.

  9. Three Dimensional Large Eddy Simulation Model of Turbulence in a Meandering Channel

    NASA Astrophysics Data System (ADS)

    Akahori, R.; Schmeeckle, M. W.

    2002-12-01

    Recent research has shown that intermittency caused by large-scale turbulence structures in rivers can be critical to accurate prediction of the sediment transport field. These large-scale turbulence structures are inherently three-dimensional. This is especially true in a river meander where strong secondary flows affect not only the three-dimensional, time-averaged flow structure, but also the process of large-scale turbulent eddy generation. It is very difficult to directly measure the turbulence field in a river except at the water surface or a few points in the interior of the flow. Numerical simulation of turbulence is a powerful tool, because it can provide information about the non-averaged flow at each grid point. Many previous researchers have calculated the time-averaged flow in a meandering channel, and obtained useful results. However, simulations of turbulence in meandering channels have been restricted to two dimensions. Therefore, they have a problem in accurately reproducing important features of the flow. We present a 3-dimenstional turbulent model for the numerical calculation of channel flow. The turbulence cannot be resolved at scales smaller than the channel grid, and we therefore parameterize the effects of small scale turbulence using standard Large Eddy Simulation (LES) assumptions. A Body Fitted Coordinate (BFC) system is employed to fit the irregular boundaries of natural channels. To solve the Navier-Stokes equations on the finite difference mesh, we employ the Cubic-Interpolated Propagation (CIP) method. The CIP method precisely solves the convective acceleration terms without numerical diffusion.

  10. Observations of Sand Dune Migration on the Colorado River in Grand Canyon using High-Resolution Multibeam Bathymetry

    NASA Astrophysics Data System (ADS)

    Kaplinski, M. A.; Buscmobe, D.; Ashley, T.; Tusso, R.; Grams, P. E.; McElroy, B. J.; Mueller, E. R.; Hamill, D.

    2015-12-01

    Repeat, high-resolution multibeam bathymetric surveys were conducted in March and July 2015 along a reach of the Colorado River in Grand Canyon near the Diamond Creek gage (362 km downstream of Lees Ferry, AZ) to characterize the migration of sand dunes. The surveys were collected as part of a study designed to quantify the relative importance of bedload and suspended sediment transport and develop a predictive relationship for bedload transport. Concurrent measurements of suspended-sediment concentrations, bed-sediment grain size, and water velocity were also collected. The study site is approximately 350 m long and 50 m wide; water depths are 7 to 10 m during normal flows; and a field of sand dunes form along its entire length with negligible coarse material at the bed surface. Full swath coverage of the site required about 6 to 10 minutes to complete with two passes of the survey vessel. Mapping occurred continuously during several survey periods. For each survey period, time-series of bathymetric maps were constructed from each pair of survey lines. In March, surveys were collected over durations of 2, 3, 9, and 11 hours, at discharges of 339 to 382 m3/s. In July, surveys were collected over durations of 4, 4, and 13 hours, at discharges ranging from 481 to 595 ft3/s. These surveys capture the migration of sand dunes over a wide range of discharge with an unprecedented temporal resolution. The dunes in March were between 30 and 50 cm in height, 5 m in length, and migrating downstream at about 1 m per hour. In July, dunes were between 75 and 130 cm in height and 10-15 m in length, and were migrating downstream at rates of 5 to 2 m per hour. The surveys also reveal that the dune migration is spatially and temporally variable, with fast-migrating small dunes variably superimposed on slower-moving larger dunes. The dunes also refract around shoreline talus piles and other flow constrictions collectively causing a large degree of dune deformation as they migrate.

  11. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 2002-2003 Annual Report.

    SciTech Connect

    Achord, Stephen; McNatt, Regan A.; Hockersmith, Eric E.

    2004-04-01

    Prior to 1992, decisions on dam operations and use of stored water relied on recoveries of branded hatchery fish, index counts at traps and dams, and flow patterns at the dams. The advent of PIT-tag technology provided the opportunity to precisely track the smolt migrations of many wild stocks as they pass through the hydroelectric complex and other monitoring sites on their way to the ocean. With the availability of the PIT tag, a more complete approach to these decisions was undertaken starting in 1992 with the addition of PIT-tag detections of several wild spring and summer chinook salmon stocks at Lower Granite Dam. Using data from these detections, we initiated development of a database on wild fish, addressing several goals of the Columbia River Basin Fish and Wildlife Program of the Pacific Northwest Electric Power Planning Council and Conservation Act (NPPC 1980). Section 304(d) of the program states, ''The monitoring program will provide information on the migrational characteristics of the various stocks of salmon and steelhead within the Columbia Basin.'' Further, Section 201(b) urges conservation of genetic diversity, which will be possible only if wild stocks are preserved. Section 5.9A.1 of the 1994 Fish and Wildlife Program states that field monitoring of smolt movement will be used to determine the best timing for water storage releases and Section 5.8A.8 states that continued research is needed on survival of juvenile wild fish before they reach the first dam with special attention to water quantity, quality, and several other factors. The goals of this ongoing study are as follows (1) Characterize the migration timing and estimate parr-to-smolt survival of different stocks of wild Snake River spring/summer chinook salmon smolts at Lower Granite Dam. (2) Determine whether consistent migration patterns are apparent. (3) Determine what environmental factors influence these patterns. (4) Characterize the migrational behavior and estimate survival of

  12. Abundance, Timing of Migration, and Egg-to-Smolt Survival of Juvenile Chum Salmon, Kwethluk River, Alaska, 2007 and 2008

    USGS Publications Warehouse

    Burril, Sean E.; Zimmerman, Christian E.; Finn, James E.; ,; Gillikin, Daniel; ,

    2010-01-01

    To better understand and partition mortality among life stages of chum salmon (Oncorhynchus keta), we used inclined-plane traps to monitor the migration of juveniles in the Kwethluk River, Alaska in 2007 and 2008. The migration of juvenile chum salmon peaked in mid-May and catch rates were greatest when water levels were rising. Movement of chum salmon was diurnal with highest catch rates occurring during the hours of low light (that is, 22:00 to 10:00). Trap efficiency ranged from 0.37 to 4.04 percent (overall efficiency = 1.94 percent). Total abundance of juvenile chum salmon was estimated to be 2.0 million fish in 2007 and 2.9 million fish in 2008. On the basis of the estimate of chum salmon females passing the Kwethluk River weir and age-specific fecundity, we estimated the potential egg deposition (PED) upstream of the weir and trapping site. Egg-to-smolt survival, calculated by dividing the estimate of juvenile chum salmon emigrating past the weir site by the estimate of PED, was 4.6 percent in 2007 and 5.2 percent in 2008. In addition to chum salmon, Chinook salmon O. tshawytscha), coho salmon (O. kisutch), sockeye salmon (O. nerka), and pink salmon (O. gorbuscha), as well as ten other fish species, were captured in the traps. As with chum salmon, catch of these species increased during periods of increasing discharge and peaked during hours of low light. This study successfully determined the characteristics of juvenile salmon migrations and estimated egg-to-smolt survival for chum salmon. This is the first estimate of survival for any juvenile salmon in the Arctic-Yukon-Kuskokwim region of Alaska and demonstrates an approach that can help to partition mortality between freshwater and marine life stages, information critical to understanding the dynamics of salmon in this region.

  13. The Fate of Oxbow Lakes Determined by Mechanisms of Meander Cutoff

    NASA Astrophysics Data System (ADS)

    Constantine, José; Dieras, Pauline; Hales, Tristram; Piégay, Hervé

    2016-04-01

    Oxbow lakes are some of the most widespread and distinctive landforms along meandering rivers, but their persistence as aquatic habitat may depend on the mechanisms of their formation. Based on an archive of historical aerial photographs and maps of seven meandering rivers, we use changes in water-surface area as a proxy for alluviation to demonstrate that oxbows and abandoned channels created by neck cutoff can persist in the floodplain for centuries, whereas the oxbows and abandoned channels created by chute cutoff appear to undergo rapid alluviation following their formation. Differences in the persistence of the thirty-seven oxbows and abandoned channels under study are due to differences in the planform characteristics that are associated with each cutoff mechanism. Using theoretical and empirical relations that describe the conditions required for the conveyance of riverbed sediment, we show that neck cutoff results in the successful transition of persistent oxbows because they lack the planform characteristics required for sustaining the flows needed to prevent plug formation. The angle by which flow is diverted and the magnitude by which the river is locally steepened is significantly greater for channels created by neck cutoff than for those created by chute cutoff.

  14. Simulating the Effects of Sea Level Rise on the Resilience and Migration of Tidal Wetlands along the Hudson River

    PubMed Central

    Tabak, Nava M.; Laba, Magdeline; Spector, Sacha

    2016-01-01

    Sea Level Rise (SLR) caused by climate change is impacting coastal wetlands around the globe. Due to their distinctive biophysical characteristics and unique plant communities, freshwater tidal wetlands are expected to exhibit a different response to SLR as compared with the better studied salt marshes. In this study we employed the Sea Level Affecting Marshes Model (SLAMM), which simulates regional- or local-scale changes in tidal wetland habitats in response to SLR, and adapted it for application in a freshwater-dominated tidal river system, the Hudson River Estuary. Using regionally-specific estimated ranges of SLR and accretion rates, we produced simulations for a spectrum of possible future wetland distributions and quantified the projected wetland resilience, migration or loss in the HRE through the end of the 21st century. Projections of total wetland extent and migration were more strongly determined by the rate of SLR than the rate of accretion. Surprisingly, an increase in net tidal wetland area was projected under all scenarios, with newly-formed tidal wetlands expected to comprise at least 33% of the HRE’s wetland area by year 2100. Model simulations with high rates of SLR and/or low rates of accretion resulted in broad shifts in wetland composition with widespread conversion of high marsh habitat to low marsh, tidal flat or permanent inundation. Wetland expansion and resilience were not equally distributed through the estuary, with just three of 48 primary wetland areas encompassing >50% of projected new wetland by the year 2100. Our results open an avenue for improving predictive models of the response of freshwater tidal wetlands to sea level rise, and broadly inform the planning of conservation measures of this critical resource in the Hudson River Estuary. PMID:27043136

  15. Simulating the Effects of Sea Level Rise on the Resilience and Migration of Tidal Wetlands along the Hudson River.

    PubMed

    Tabak, Nava M; Laba, Magdeline; Spector, Sacha

    2016-01-01

    Sea Level Rise (SLR) caused by climate change is impacting coastal wetlands around the globe. Due to their distinctive biophysical characteristics and unique plant communities, freshwater tidal wetlands are expected to exhibit a different response to SLR as compared with the better studied salt marshes. In this study we employed the Sea Level Affecting Marshes Model (SLAMM), which simulates regional- or local-scale changes in tidal wetland habitats in response to SLR, and adapted it for application in a freshwater-dominated tidal river system, the Hudson River Estuary. Using regionally-specific estimated ranges of SLR and accretion rates, we produced simulations for a spectrum of possible future wetland distributions and quantified the projected wetland resilience, migration or loss in the HRE through the end of the 21st century. Projections of total wetland extent and migration were more strongly determined by the rate of SLR than the rate of accretion. Surprisingly, an increase in net tidal wetland area was projected under all scenarios, with newly-formed tidal wetlands expected to comprise at least 33% of the HRE's wetland area by year 2100. Model simulations with high rates of SLR and/or low rates of accretion resulted in broad shifts in wetland composition with widespread conversion of high marsh habitat to low marsh, tidal flat or permanent inundation. Wetland expansion and resilience were not equally distributed through the estuary, with just three of 48 primary wetland areas encompassing >50% of projected new wetland by the year 2100. Our results open an avenue for improving predictive models of the response of freshwater tidal wetlands to sea level rise, and broadly inform the planning of conservation measures of this critical resource in the Hudson River Estuary. PMID:27043136

  16. Simulating the Effects of Sea Level Rise on the Resilience and Migration of Tidal Wetlands along the Hudson River.

    PubMed

    Tabak, Nava M; Laba, Magdeline; Spector, Sacha

    2016-01-01

    Sea Level Rise (SLR) caused by climate change is impacting coastal wetlands around the globe. Due to their distinctive biophysical characteristics and unique plant communities, freshwater tidal wetlands are expected to exhibit a different response to SLR as compared with the better studied salt marshes. In this study we employed the Sea Level Affecting Marshes Model (SLAMM), which simulates regional- or local-scale changes in tidal wetland habitats in response to SLR, and adapted it for application in a freshwater-dominated tidal river system, the Hudson River Estuary. Using regionally-specific estimated ranges of SLR and accretion rates, we produced simulations for a spectrum of possible future wetland distributions and quantified the projected wetland resilience, migration or loss in the HRE through the end of the 21st century. Projections of total wetland extent and migration were more strongly determined by the rate of SLR than the rate of accretion. Surprisingly, an increase in net tidal wetland area was projected under all scenarios, with newly-formed tidal wetlands expected to comprise at least 33% of the HRE's wetland area by year 2100. Model simulations with high rates of SLR and/or low rates of accretion resulted in broad shifts in wetland composition with widespread conversion of high marsh habitat to low marsh, tidal flat or permanent inundation. Wetland expansion and resilience were not equally distributed through the estuary, with just three of 48 primary wetland areas encompassing >50% of projected new wetland by the year 2100. Our results open an avenue for improving predictive models of the response of freshwater tidal wetlands to sea level rise, and broadly inform the planning of conservation measures of this critical resource in the Hudson River Estuary.

  17. Richness and diversity of helminth communities in the Japanese grenadier anchovy, Coilia nasus, during its anadromous migration in the Yangtze River, China.

    PubMed

    Li, Wen X; Zou, Hong; Wu, Shan G; Song, Rui; Wang, Gui T

    2012-06-01

    To determine the relationship between the species richness, diversity of helminth communities, and migration distance during upward migration from coast to freshwater, helminth communities in the anadromous fish Coilia nasus were investigated along the coast of the East China Sea, the Yangtze Estuary, and 3 localities on the Yangtze River. Six helminth species were found in 224 C. nasus . Changes in salinity usually reduced the survival time of parasites, and thus the number of helminth species and their abundance. Except for the 2 dominant helminths, the acanthocephalan Acanthosentis cheni and the nematode Contracaecum sp., mean abundance of other 4 species of helminths was rather low (<1.0) during the upward migration in the Yangtze River. Mean abundance of the 2 dominant helminths peaked in the Yangtze Estuary and showed no obvious decrease among the 3 localities on the Yangtze River. Mean species richness, Brillouin's index, and Shannon index were also highest in the estuary (1.93 ± 0.88, 0.28 ± 0.25, and 0.37 ± 0.34, respectively) and did not exhibit marked decline at the 3 localities on the Yangtze River. A significant negative correlation was not seen between the similarity and the geographical distance (R  =  -0.5104, P  =  0.1317). The strong salinity tolerance of intestinal helminths, relatively brief stay in the Yangtze River, and large amount of feeding on small fish and shrimp when commencing spawning migration perhaps were responsible for the results.

  18. Migration of the Pee Dee River system inferred from ancestral paleochannels underlying the South Carolina Grand Strand and Long Bay inner shelf

    USGS Publications Warehouse

    Baldwin, W.E.; Morton, R.A.; Putney, T.R.; Katuna, M.P.; Harris, M.S.; Gayes, P.T.; Driscoll, N.W.; Denny, J.F.; Schwab, W.C.

    2006-01-01

    Several generations of the ancestral Pee Dee River system have been mapped beneath the South Carolina Grand Strand coastline and adjacent Long Bay inner shelf. Deep boreholes onshore and high-resolution seismic-reflection data offshore allow for reconstruction of these paleochannels, which formed during glacial lowstands, when the Pee Dee River system incised subaerially exposed coastal-plain and continental-shelf strata. Paleochannel groups, representing different generations of the system, decrease in age to the southwest, where the modern Pee Dee River merges with several coastal-plain tributaries at Winyah Bay, the southern terminus of Long Bay. Positions of the successive generational groups record a regional, southwestward migration of the river system that may have initiated during the late Pliocene. The migration was primarily driven by barrier-island deposition, resulting from the interaction of fluvial and shoreline processes during eustatic highstands. Structurally driven, subsurface paleotopography associated with the Mid-Carolina Platform High has also indirectly assisted in forcing this migration. These results provide a better understanding of the evolution of the region and help explain the lack of mobile sediment on the Long Bay inner shelf. Migration of the river system caused a profound change in sediment supply during the late Pleistocene. The abundant fluvial source that once fed sand-rich barrier islands was cut off and replaced with a limited source, supplied by erosion and reworking of former coastal deposits exposed at the shore and on the inner shelf.

  19. Richness and diversity of helminth communities in the Japanese grenadier anchovy, Coilia nasus, during its anadromous migration in the Yangtze River, China.

    PubMed

    Li, Wen X; Zou, Hong; Wu, Shan G; Song, Rui; Wang, Gui T

    2012-06-01

    To determine the relationship between the species richness, diversity of helminth communities, and migration distance during upward migration from coast to freshwater, helminth communities in the anadromous fish Coilia nasus were investigated along the coast of the East China Sea, the Yangtze Estuary, and 3 localities on the Yangtze River. Six helminth species were found in 224 C. nasus . Changes in salinity usually reduced the survival time of parasites, and thus the number of helminth species and their abundance. Except for the 2 dominant helminths, the acanthocephalan Acanthosentis cheni and the nematode Contracaecum sp., mean abundance of other 4 species of helminths was rather low (<1.0) during the upward migration in the Yangtze River. Mean abundance of the 2 dominant helminths peaked in the Yangtze Estuary and showed no obvious decrease among the 3 localities on the Yangtze River. Mean species richness, Brillouin's index, and Shannon index were also highest in the estuary (1.93 ± 0.88, 0.28 ± 0.25, and 0.37 ± 0.34, respectively) and did not exhibit marked decline at the 3 localities on the Yangtze River. A significant negative correlation was not seen between the similarity and the geographical distance (R  =  -0.5104, P  =  0.1317). The strong salinity tolerance of intestinal helminths, relatively brief stay in the Yangtze River, and large amount of feeding on small fish and shrimp when commencing spawning migration perhaps were responsible for the results. PMID:22257179

  20. Freedom space for rivers: a sustainable management approach to enhance river resilience.

    PubMed

    Biron, Pascale M; Buffin-Bélanger, Thomas; Larocque, Marie; Choné, Guénolé; Cloutier, Claude-André; Ouellet, Marie-Audray; Demers, Sylvio; Olsen, Taylor; Desjarlais, Claude; Eyquem, Joanna

    2014-11-01

    River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of "freedom space" are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions.

  1. Freedom space for rivers: a sustainable management approach to enhance river resilience.

    PubMed

    Biron, Pascale M; Buffin-Bélanger, Thomas; Larocque, Marie; Choné, Guénolé; Cloutier, Claude-André; Ouellet, Marie-Audray; Demers, Sylvio; Olsen, Taylor; Desjarlais, Claude; Eyquem, Joanna

    2014-11-01

    River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of "freedom space" are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions. PMID:25195034

  2. Freedom Space for Rivers: A Sustainable Management Approach to Enhance River Resilience

    NASA Astrophysics Data System (ADS)

    Biron, Pascale M.; Buffin-Bélanger, Thomas; Larocque, Marie; Choné, Guénolé; Cloutier, Claude-André; Ouellet, Marie-Audray; Demers, Sylvio; Olsen, Taylor; Desjarlais, Claude; Eyquem, Joanna

    2014-11-01

    River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of "freedom space" are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions.

  3. Survival and migration route probabilities of juvenile Chinook salmon in the Sacramento-San Joaquin River Delta during the winter of 2009-10

    USGS Publications Warehouse

    Perry, Russell W.; Romine, Jason G.; Brewer, Scott J.; LaCivita, Peter E.; Brostoff, William N.; Chapman, Eric D.

    2012-01-01

    Juvenile Chinook salmon (Oncorhynchus tshawytscha) emigrating from natal tributaries of the Sacramento River may use a number of migration routes to negotiate the Sacramento-San Joaquin River Delta (hereafter, "the Delta"), each of which may influence their probability of surviving. We applied a mark-recapture model to data from acoustically tagged juvenile late-fall Chinook salmon that migrated through the Delta during the winter of 2009-10 (hereafter, 2010). This report presents findings from our fourth year of research. We estimated route-specific survival for four release groups: two release groups that migrated through the Delta in December 2009 and January 2010, and two release groups that migrated during February 2010. Population-level survival through the Delta (SDelta) ranged from 0.374 (SE = 0.040) to 0.524 (SE = 0.034) among releases. Although river flows for the February release groups were substantially higher (20,000-40,000 ft3/s at Freeport) than for the December release groups (about 10,000 ft3/s), SDelta did not differ considerably between release groups. Among migration routes, fish migrating through the Sacramento River exhibited the highest survival, and fish entering the interior Delta exhibited the lowest survival. Fish entering Sutter and Steamboat Sloughs had lower survival than fish entering the Sacramento River during December, but similar survival during February. These patterns were consistent among release groups, and strikingly similar to patterns observed in previous years. Migration routing varied among release groups partly because of differences in river discharge between releases. For the two December release groups, 26.5 and 28.9 percent of fish entered the interior Delta; for the two February release groups, 10.4 and 17.9 percent of fish entered the interior Delta. Differences in routing probabilities between December and February are partly related to the inverse relationship between flow and the fraction of discharge entering

  4. Flow structure in submarine meandering channels, a continuous discussion on secondary flow

    NASA Astrophysics Data System (ADS)

    Abad, J. D.; Parker, G.; Sequeiros, O.; Spinewine, B.; Garcia, M. H.; Pirmez, C.

    2011-12-01

    The understanding of the flow structure in deep-sea turbidity currents is important for the formation of submarine meandering channels. Similarly to the case of subaerial channels, several types of secondary flows include turbulence-, curvature- and bed morphodynamic-driven flow structures that modulate sediment transport and channel bed morphodynamics. This study focuses on [1] a review of long-time research effort (Abad et al., 2011) that tackles the description of the secondary flow associated with a subaqueous bottom current (saline) in a high-curvature meandering channel and [2] ongoing numerical simulations of similar settings as the experiments to describe the entire flow structure. In the case of subaerial channels, the classical Rozovskiian paradigm is often invoked which indicates that the near-bottom secondary flow in a bend is directed inward. It has recently been suggested based on experimental and theoretical considerations, however, that this pattern is reversed (near-bottom secondary flow is directed outward) in the case of submarine meandering channels. Experimental results presented here, on the other hand, indicate near-bottom secondary flows that have the same direction as observed in a river (normal secondary flow). The implication is an apparent contradiction between experimental results. This study combines theory, experiments, reconstructions of field flows and ongoing simulations to resolve this apparent contradiction based on the flow densimetric Froude number. Three ranges of densimetric Froude number are found, such that a) in an upper regime, secondary flow is reversed, b) in a middle regime, it is normal and c) in a lower regime, it is reversed. These results are applied to field scale channel-forming turbidity currents in the Amazon submarine canyon-fan system (Amazon Channel) and the Monterey canyon and a saline underflow in the Black Sea flowing from the Bosphorus. Our analysis indicates that secondary flow should be normal

  5. Investigating historical changes in morphodynamic processes associated with channelization of a large Alpine river: the Etsch/Adige River, NE Italy

    NASA Astrophysics Data System (ADS)

    Zen, Simone; Scorpio, Vittoria; Mastronunzio, Marco; Proto, Matteo; Zolezzi, Guido; Bertoldi, Walter; Comiti, Francesco; Surian, Nicola; Prà, Elena Dai

    2016-04-01

    River channel management within the last centuries has largely modified fluvial processes and morphodynamic evolution of most large European rivers. Several river systems experienced extensive channelization early in the 19th century, thus strongly challenging our present ability to detect their morphodynamic functioning with contemporary photogrammetry or cartographical sources. This consequently leaves open questions about their potential future response, especially to management strategies that "give more room" to the river, aiming at partially rehabilitating their natural functioning. The Adige River (Etsch in German), the second longest Italian river, is an exemplary case where channelization occurred more than 150 years ago, and is the focus of the present work. This work aims (i) to explore changes in fundamental morphodynamic processes associated with massive channelization of the Adige River and (ii) to quantify the alteration in river bars characteristics, by using morphodynamic models of bars and meandering. To fulfil our aims we combine the analysis of historical data with morphodynamic mathematical modelling. Historical sources (recovered in a number of European archives), such as hydrotopographical maps, airborne photogrammetry and hydrological datasets were collected to investigate channel morphology before and after the channelization. Information extracted from this analysis was combined with morphodynamic linear models of free migrating and forced steady bars, to investigate river bars and bend stability properties under different hydromorphological scenarios. Moreover, a morphodynamic model for meandering channel was applied to investigate the influence of river channel planform on the evolution of the fluvial bars. Results from the application of morphodynamic models allowed to predict the type, position and geometry of bars characterizing the channelized configuration of the river, and to explain the presently observed relative paucity of bars

  6. [Migration of main odorous compounds in a water supply system with Huangpu River as raw water in Shanghai].

    PubMed

    Bai, Xiao-Hui; Zhang, Ming-De; Jia, Cheng-Shen

    2011-01-01

    Migration and variation of odorous compounds as geosmin, 2-methylisoborneol (MIB) and residual chlorine in drinking water taken from Huangpu River were studied by using headspace solid phase microextraction procedure (HSPME) and gas chromatograph with mass spectrometry. The results showed that, raw water, processed water, pipe water (taken from pump station) and secondary-supply water all contained MIB and geosmin ranging from 2 ng/L to 18 ng/L and 2.68 ng/L to 5.06 ng/L respectively and decreased dramatically during the water processing and distribution system. MIB is proved to be a kind of the odorous compounds in drinking water of Shanghai by comparing the concentrations of MIB and GSM with their odor threshold. The concentration of residual chlorine declined greatly in the distribution system, but because of the high value at the outlet of waterworks, it still may exceeded the influence of MIB and cause the odour problems.

  7. Determination of Swimming Speeds and Energetic Demands of Upriver Migrating Fall Chinook Salmon (Oncorhynchus Tshawytscha) in the Klickitat River, Washington.

    SciTech Connect

    Brown, Richard S.; Geist, David R.; Confederated Tribes and Bands of the Yakama Nation, Washington

    2002-08-30

    This report describes a study conducted by Pacific Northwest National Laboratory for the Bonneville Power Administration's Columbia Basin Fish and Wildlife Program during the fall of 2001. The objective was to study the migration and energy use of adult fall chinook salmon (Oncorhynchus tshawytscha) traveling up the Klickitat River to spawn. The salmon were tagged with either surgically implanted electromyogram (EMG) transmitters or gastrically implanted coded transmitters and were monitored with mobile and stationary receivers. Swim speed and aerobic and anaerobic energy use were determined for the fish as they attempted passage of three waterfalls on the lower Klickitat River and as they traversed free-flowing stretches between, below, and above the falls. Of the 35 EMG-tagged fish released near the mouth of the Klickitat River, 40% passed the first falls, 24% passed the second falls, and 20% made it to Lyle Falls. None of the EMG-tagged fish were able to pass Lyle Falls, either over the falls or via a fishway at Lyle Falls. Mean swimming speeds ranged from as low as 52.6 centimeters per second (cm s{sup -1}) between falls to as high as 189 (cm s{sup -1}) at falls passage. Fish swam above critical swimming speeds while passing the falls more often than while swimming between the falls (58.9% versus 1.7% of the transmitter signals). However, fish expended more energy swimming the stretches between the falls than during actual falls passage (100.7 to 128.2 kilocalories [kcals] to traverse areas between or below falls versus 0.3 to 1.0 kcals to pass falls). Relationships between sex, length, and time of day on the success of falls passage were also examined. Average swimming speeds were highest during the day in all areas except at some waterfalls. There was no apparent relationship between either fish condition or length and successful passage of waterfalls in the lower Klickitat River. Female fall chinook salmon, however, had a much lower likelihood of passing

  8. Smolt Migration Characteristics and Mainstem Snake and Columbia River Detection Rates of PIT-Tagged Grande Ronde and Imnaha River Naturally Produced Spring Chinook Salmon, Annual Reports 1993, 1994, 1995 : Fish Research Project, Oregon.

    SciTech Connect

    Walters, Timothy R.; Carmichael, Richard W.; Keefe, MaryLouise

    1996-04-01

    This reports on the second, third, and fourth years of a multi-year study to assess smolt migration characteristics and cumulative detection rates of naturally produced spring chinook salmon (Oncorhynchus tshawytscha) from Northeast Oregon streams. The goal of this project is to develop an understanding of interpopulational and interannual variation in several early life history parameters of naturally produced spring and summer chinook salmon in the Grande Ronde and Imnaha River subbasins. This project will provide information to assist chinook salmon population recovery efforts. Specific populations included in the study are: (1) Catherine Creek; (2) Upper Grande Ronde River; (3) Lostine River; (4) Imnaha River; (5) Wenaha River; and (6) Minam River. In this document, the authors present findings and activities from research completed in 1993, 1994, and 1995.

  9. Modelling the Future Hydroclimatology of the Lower Fraser River and its Impacts on the Spawning Migration Survival of Sockeye Salmon

    NASA Technical Reports Server (NTRS)

    Hague, M. J.; Ferrari, M. R.; Miller, J. R.; Patterson, D. A.; Russell, G. L.; Farrell, A.P.; Hinch, S. G.

    2010-01-01

    Short episodic high temperature events can be lethal for migrating adult Pacific salmon (Oncorhynchus spp.). We downscaled temperatures for the Fraser River, British Columbia to evaluate the impact of climate warming on the frequency of exceeding thermal thresholds associated with salmon migratory success. Alarmingly, a modest 1.0 C increase in average summer water temperature over 100 years (1981-2000 to 2081-2100) tripled the number of days per year exceeding critical salmonid thermal thresholds (i.e. 19.0 C). Refined thresholds for two populations (Gates Creek and Weaver Creek) of sockeye salmon (Oncorhynchus nerka) were defined using physiological constraint models based on aerobic scope. While extreme temperatures leading to complete aerobic collapse remained unlikely under our warming scenario, both populations were increasingly forced to migrate upriver at reduced levels of aerobic performance (e.g. in 80% of future simulations, => 90% of salmon encountered temperatures exceeding population specific thermal optima for maximum aerobic scope; T(sub opt)) = 16.3 C for Gates Creek and T(sub sopt)=14.5 C for Weaver Creek). Assuming recent changes to river entry timing persist, we also predicted dramatic increases in the probability of freshwater mortality for Weaver Creek salmon due to reductions in aerobic, and general physiological, performance (e.g. in 42% of future simulations =>50% of Weaver Creek fish exceeded temperature thresholds associated with 0 - 60% of maximum aerobic scope). Potential for adaptation via directional selection on run-timing was more evident for the Weaver Creek population. Early entry Weaver Creek fish experienced 25% (range: 15 - 31%) more suboptimal temperatures than late entrants, compared with an 8% difference (range: 0 - 17%) between early and late Gates Creek fish. Our results emphasize the need to consider daily temperature variability in association with population-specific differences in behaviour and physiological

  10. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Smolts, 1993 Annual Report.

    SciTech Connect

    Achord, Stephen; Kamikawa, Daniel J.; Sandford, Benjamin P.

    1995-01-01

    The goals of this study are to (1) characterize the outmigration timing of different wild stocks of spring/summer chinook salmon smolts at dams on the Snake and Columbia Rivers, (2) determine if consistent patterns are apparent, and (3) determine what environmental factors influence outmigration timing.

  11. Molecular detection of Campylobacter spp. and fecal indicator bacteria during the northern migration of Sandhill Cranes (Grus canadensis) at the Central Platte River

    EPA Science Inventory

    The annual Sandhill crane (Grus canadensis) migration through Nebraska is thought to be a major source of fecal pollution to the Platte River, but of unknown human health risk. To better understand potential risks, the presence of Campylobacter species and fecal bacteria were exa...

  12. Use of electromyogram telemetry to assess swimming activity of adult spring Chinook salmon migrating past a Columbia River dam

    USGS Publications Warehouse

    Brown, R.S.; Geist, D.R.; Mesa, M.G.

    2006-01-01

    Electromyogram (EMG) radiotelemetry was used to estimate the swim speeds of spring Chinook salmon Oncorhynchus tshawytscha migrating upstream past a Columbia River dam. Electrodes from EMG transmitters were surgically implanted in the red muscle of fish captured at Bonneville Dam, and output from the tags was calibrated to defined swim speeds for each fish in a tunnel respirometer. The fish were then released below Bonneville Dam and radio-tracked as they migrated through the tailraces, fishways, and forebays of the dam. On average, swim speed was significantly higher when tagged salmon were moving through tailraces than when they were moving through other parts of the dam. Specifically, swim speeds for fish in tailraces (106.4 cm/s) were 23% higher than those of fish in fishways (84.9 cm/s) and 32% higher than those of fish in forebays (80.2 cm/s). Swim speeds were higher in fishways during the day than during the night, but there were no diel differences in swim speeds in tailraces and forebays. During dam passage, Chinook salmon spent the most time in tailraces, followed by fishways and forebays. ?? Copyright by the American Fisheries Society 2006.

  13. Upstream Migration of Pacific Lampreys in the John Day River : Behavior, Timing, and Habitat Use : Annual Report 2000.

    SciTech Connect

    Bayer, Jennifer M.; Seelye, James G.; Robinson, T. Craig

    2001-04-12

    Historic accounts and recent observations of Pacific lampreys (Lampetra tridentata) at mainstem Columbia River dams indicate the number of Pacific lampreys migrating upriver has decreased dramatically over the last 60 years. Consequently, state, federal, and tribal governments have recently expressed concern for this species. Little is known about the biological and ecological characteristics of habitats suitable for upstream migrating Pacific lampreys. If rehabilitation efforts are to be done effectively and efficiently, we must gain knowledge of factors limiting survival and reproduction of Pacific lampreys. From data gathered in the first year of this project, we can for the first time, describe the timing, extent, and patterns of movements for Pacific lampreys. We have tested methods and gained information that will allow us to refine our objectives and approach in future work. Knowledge of behavior, timing, and the resulting quantification of habitat use will provide a means to assess the suitability of overwintering and spawning habitats and allow the establishment of goals for recovery projects. Further research is necessary, including multiple years of data collection, tracking of movement patterns through the spawning season, and more rigorously examining habitat use.

  14. Radiocesium distribution along the slope in the Iput river basin as a tracer of the contaminant secondary migration

    NASA Astrophysics Data System (ADS)

    Korobova, Elena; Romanov, Sergey; Beriozkin, Victor; Dogadkin, Nikolay

    2016-04-01

    The main goal of the study performed in 2014-2015 at the test site located in the abandoned zone of the Iput river basin was to study detailed patterns of Cs-137 redistribution along the terrace slope and the adjacent floodplain depression almost 30 years after the Chernobyl accident. Cs-137 surface activity was measured with the help of modified field gamma-spectrometer Violinist III (USA) in a grid 2 m x 2 m within the test plot sized 10 m x 24 m. Gamma-spectrometry was accompanied by topographical survey. Cs-137 depth distribution was studied by soil core sampling in increments of 2 cm and 5 cm down to 40 cm depth. Cs-137 activity in soil samples was measured in laboratory conditions by Nokia gamma-spectrometer. The results showed distinct natural dissimilarity of Cs-137 surface activity within the undisturbed soil of slope. Cs-137 depth migration in successive soil cores marked different patterns correlated with the position in relief. In particular cores Cs-137 depth variation correlated with water regime that shows that the processes of secondary distribution of Cs-137 along the slope obviously depend upon water migration. The finding is important for understanding of regularities in patterns of radiocesium spatial distribution.

  15. River Elongation as a Proxy for Lateral Channel Activity

    NASA Astrophysics Data System (ADS)

    Lauer, J. W.

    2009-12-01

    Lateral channel movement is a process that is tightly linked to both channel hydraulics and sediment transport, strongly influences floodplain ecology, and also has great relevance for banktop property owners. The correlation between channel migration rate and channel curvature usually causes meandering river channels to elongate as they migrate laterally. Over the long term, the increase in sinuosity is compensated by a rapid decrease in sinuosity where and when river bends shorten through cutoff processes. However, the elongation for most meander bends in systems free to migrate across wide floodplains often occurs relatively uniformly throughout the system. Consequently, the rate of elongation of individual river bends, integrated across a river reach, offers a simple mechanism for characterizing the reach’s lateral activity. Spatial series of accumulated elongation can also be used to delineate reaches with similar properties. We use aerial imagery pairs to compare rates of lateral channel centerline shifting with channel centerline elongation for reaches many bends long along eight different rivers with widths ranging from 12 to 584 m. Except where bends translate downstream without changing form, elongation rates are closely linked to lateral shifting. In several cases, a change in elongation rate corresponds closely with a change in channel width, discharge, and/or bed material. For reaches free to migrate across a wide, unconfined floodplain and where lateral migration measurements are likely of high quality, the average ratio between the reach average migration rate normalized by channel width and the rate of sinuosity increase (excluding bends that experienced a cutoff between imagery dates) is approximately 5.6. Since elongation rate measurements can be made accurately even from photos that are poorly aligned, the relationship between sinuosity increase and lateral migration potentially provides a means of bypassing time-consuming georeferencing

  16. Diurnal characteristics of migration and transformation of mercury and effects of nitrate in Jialing River, Chongqing, China.

    PubMed

    Sun, Rongguo; Wang, Dingyong; Mao, Wen; Ma, Ming; Zhang, Cheng; Jiang, Tao

    2015-01-01

    Laboratory incubation experiments were performed to identify diurnal characteristics of migration and transformation of mercury (Hg) and effects of nitrate (NO3(-), a hydroxyl radical donor by photolysis) in Jialing River, Chongqing, China. It is found that there are strong diurnal signals of [monomethylmercury (MMHg)] and [reactive Hg (RHg)] in sediment, pore water and overlying water, which suggest that solar radiation may be an important variable that involved in aquatic Hg cycling. Photo-degradation (PD) of MMHg plays a key role in Hg cycling in water systems, and the rates are measured to be 38.22% in March, 2012. The presence of NO3(-) has a marked effect on MMHg PD under solar radiation, and affects inorganic species reducting to Hg(0), resulting in more Hg species available for methylation. So NO3(-) is an important factor for Hg cycling in water systems. Diffusive flux of MMHg, RHg and dissolved Hg (DHg) are 1.92-2.34, 3.43-3.64 and 3.04-5.71 ng m(-2) d(-1) at daytime, and 6.04-6.92, 3.22-3.25 and 7.79-8.37 ng m(-2) d(-1) at nighttime, respectively, implying that sediment is a major Hg source for shallow-water area in Jialing River at springtime. These results show great importance for understanding Hg biogeochemical processes in clear, oligotrophic, shallow, sluggish, and agriculturally-impacted waters.

  17. A barrier to upstream migration in the fish passage of Itaipu Dam (Canal da Piracema), Paraná River basin

    USGS Publications Warehouse

    ,; Fontes Júnior, Hélio Martins; Makrakis, Sergio; Gomes, Luiz Carlos; Latini, João Dirço

    2012-01-01

    The majority of the fish passages built in the Neotropical region are characterised by low efficiency and high selectivity; in many cases, the benefits to fish populations are uncertain. Studies conducted in the Canal da Piracema at Itaipu dam on the Parana River indicate that the system component designated as the Discharge channel in the Bela Vista River (herein named Canal de deságue no rio Bela Vista or CABV), a 200 m long technical section, was the main barrier to the upstream migration. The aim of this study was to evaluate the degree of restriction imposed by the CABV on upstream movements of Prochilodus lineatus and Leporinus elongatus, Characiformes. Fish were tagged with passive integrated transponders (PIT tags) and released both downstream and upstream of this critical section. Individuals of both species released downstream of the CABV took much more time to reach the upper end of the system (43.6 days vs. 15.9 days), and passed in much lower proportions (18% vs. 60.8%) than those tagged upstream of this component. Although more work is needed to differentiate between fishway effects and natural variation in migratory motivation, the results clearly demonstrate passage problems at the CABV.

  18. Migration of global radioactive fallout to the Arctic Ocean (on the example of the Ob's river drainage basin).

    PubMed

    Miroshnikov, A; Semenkov, I

    2012-11-01

    This article provides an assessment of the impact of global fallout on (137)Cs contamination in the bottom sediments of Kara Sea. The erosiveness of 10th-level river basins was estimated by landscape-geochemical and geomorphological characteristics. All 10th-level basins (n=154) were separated into three groups: mountain, mountain-lowland and plain. Four different types of basins were identified depending on the geochemical conditions of the migration of radiocaesium in the plain and mountain-lowland. Classifications of types were carried out using the geographic information systems-based approach. The Ob River's macroarena covers 3.5 million km(2). Internal drainage basins cover 23 % of the macroarena and accumulate whole radiocaesium from the global fallout. The remaining territory is transitional for the (137)Cs. The field research works performed in the three plain first-level basins allow one to estimate the radiocaesium run-off. The calculations show that 7 % of (137)Cs was removed from the first-level basin in arable land. Accumulation of radiocaesium in the first-level basin under undisturbed forest is 99.8 %. The research shows that (137)Cs transfer from the humid basins is in the range of 6.9-25.5 TBq and for semi-humid basins 5.6-285.5 TBq. The areas of these basins cover 40 and 8 % of the Ob River's macroarena, respectively. Drainage lakes and reservoir drainage basins make up 22 % of the macroarena. Mountainous and semi-arid drainage basins cover 7 % of the macroarena.

  19. Design and implementation of an emergency environmental responsesystem to protect migrating salmon in the lower San Joaquin River,California

    SciTech Connect

    Quinn, Nigel W.T.; Jacobs, Karl C.

    2006-01-30

    In the past decade tens of millions of dollars have beenspent by water resource agencies in California to restore the nativesalmon fishery in the San Joaquin River and its major tributaries. Anexcavated deep water ship channel (DWSC), through which the river runs onits way to the Bay/Delta and Pacific Ocean, experiences episodes of lowdissolved oxygen which acts as a barrier to anadromous fish migration anda threat to the long-term survival of the salmon run. An emergencyresponse management system is under development to forecast theseepisodes of low dissolved oxygen and to deploy measures that will raisedissolved oxygen concentrations to prevent damage to the fisheryresource. The emergency response management system has been designed tointeract with a real-time water quality monitoring network and is servedby a comprehensive data management and forecasting model toolbox. TheBay/Delta and Tributaries (BDAT) Cooperative Data Management System is adistributed, web accessible database that contains terabytes ofinformation on all aspects of the ecology of the Bay/Delta and upperwatersheds. The complexity of the problem dictates data integration froma variety of monitoring programs. A unique data templating system hasbeen constructed to serve the needs of cooperating scientists who wish toshare their data and to simplify and streamline data uploading into themaster database. In this paper we demonstrate the utility of such asystem in providing decision support for management of the San JoaquinRiver fishery. We discuss how the system might be expanded to havefurther utility in coping with other emergencies and threats to watersupply system serving California's costal communities.

  20. Channel pattern and river-floodplain dynamics in forested mountain river systems

    NASA Astrophysics Data System (ADS)

    Beechie, Timothy J.; Liermann, Martin; Pollock, Michael M.; Baker, Sarah; Davies, Jeremy

    2006-08-01

    Channel pattern effectively stratifies the dynamics of rivers and floodplains in forested mountain river systems of the Pacific Northwest, USA. Straight channels are least dynamic, with relatively slow floodplain turnover and floodplains dominated by old surfaces. Braided channels are most dynamic, with floodplain turnover as low as 25 years and predominantly young floodplain surfaces. Island-braided and meandering channels have intermediate dynamics, with moderately frequent disturbances (erosion of floodplain patches) maintaining a mix of old and young surfaces. Return intervals for the erosion of floodplains increase in the order of braided, island-braided, meandering, and straight (8, 33, 60, and 89 years, respectively). A threshold for the lateral migration of a channel occurs at a bankfull width of 15-20 m. The most likely mechanism underlying this threshold is that larger channels are deep enough to erode below the rooting zone of bank vegetation. Above this threshold, channels not confined between valley walls exhibit channel patterns distinguishable by slope and discharge, and slope-discharge domains can be used to predict channel patterns. Meandering and braided patterns are most consistently identified by the model, and prediction errors are largely associated with indistinct transitions among channel patterns that are adjacent in plots of slope against discharge. Locations of straight channels are difficult to identify accurately with the current model. The predicted spatial distribution of channel patterns reflects a downstream decline in channel slope, which is likely correlated with a declining ratio of bed load to suspended load. Ecological theory suggests that biological diversity should be highest where the intermediate disturbance regime of island-braided channels sustains high diversity of habitat and successional states through time.

  1. Smolt Migration Characteristics and Mainstem Snake and Columbia River Detection Rates of PIT-Tagged Grande Ronde and Imnaha River Naturally-Produced Spring Chinook Salmon, 1996 Annual Report : Fish Research Project, Oregon.

    SciTech Connect

    Sankovich, Paul; Keefe, MaryLouise; Carmichael, Richard W.

    1997-01-01

    This is the fifth year of a multi-year study to assess smolt migration characteristics and cumulative detection rates of naturally-produced chinook salmon (Oncorhynchus tshawytscha), from northeast Oregon streams. The goal of this project is to develop an understanding of interpopulation and interannual variation in several early life history characteristics of naturally-produced chinook salmon from the Grande Ronde and Imnaha River subbasins. This project provides information useful in the recovery of listed Snake River spring/summer chinook salmon. Specific populations included in the study are (1) Catherine Creek, (2) upper Grande Ronde River, (3) Lostine River, (4) Imnaha River, (5) Wenaha River, and (6) Minam River. In this document, we present findings from research completed in 1996. Naturally-produced chinook salmon populations in the Grande Ronde and Imnaha River subbasins have declined drastically in recent years due in part to habitat alterations and hydropower development. Declines have continued despite extensive mitigation efforts, including fish passage improvements, artificial production, supplementation, and habitat modification (BPA Division of Fish and Wildlife 1990). Snake River spring/summer chinook salmon (hereafter referred to as chinook salmon), which include naturally-produced chinook salmon in the Grande Ronde and Imnaha River subbasins, have been listed under the Endangered Species Act of 1973 as threatened or endangered since 1992.

  2. Radionuclide migration at the Koongarra uranium deposit, Northern Australia Lessons from the Alligator Rivers analogue project

    NASA Astrophysics Data System (ADS)

    Payne, Timothy E.; Airey, Peter L.

    The Koongarra uranium deposit in Northern Australia provides a ‘natural analogue’ for processes that are of relevance for assessing the safety of radioactive waste disposal. In an international project extending over two decades, the Koongarra ore body was studied to increase the understanding of radionuclide migration and retention mechanisms that might occur in the vicinity of a geological repository. The research effort included extensive characterisation of the geological, hydrological and geochemical conditions at the site. Patterns of the distribution of radionuclides (predominantly members of the 238U decay chain, but also the rare isotopes 239Pu, 99Tc and 129I) were studied in both solid and groundwater phases. The project included detailed studies of uranium adsorption on mineral surfaces, and of subsequent processes that may lead to long-term uranium immobilisation. Numerous models for uranium migration were developed during the project. This paper provides a comprehensive review of the research at Koongarra, and assesses the value of the site for integrating the results of a complex series of laboratory, modelling and field studies. The insights gained from this review of the Koongarra project may assist in maximising the potential scientific benefit of future natural analogue studies.

  3. Flood Deposition Patterns and Channel Migration due to a 10-year flood event: the case of the Indus River flood 2010

    NASA Astrophysics Data System (ADS)

    Kettner, A. J.; Syvitski, J. P.; Overeem, I.; Brakenridge, G. R.

    2013-12-01

    Fluvial geomorphological processes evolve the landscape and are often referred to as processes that act for hundred to thousands of years before making a noticeable change in landforms. For the Indus River, landscape evolution has been intensified due to human interference. Failure in repairing its levees from previous floods led in July 2010 during a not exceptional discharge event (~10 year recurrence interval) to a large avulsion and flooding disaster that caused ~2,000 fatalities. Examining pre- and post flood maps by analyzing MODIS and ASTER-A1 data allowed us to determine the extent of sandy flood deposits and to quantify channel migration patterns. The typical pattern of inner bend deposition (due to helical flow) and outer bend erosion were less pronounced. We hypothesize that when flow exceeds bankfull conditions, deposition is more uniform and no longer constrained by the streambed geometry. We observe that the inner and the outer river bend receive similar amounts of sandy deposits (43% versus 57% respectively). Crevasse splaying was widespread and appeared to occur as a flow stripping process again both upon the point bars as well as in river outer bends. Channel activity (defined as the areal shift of the pre- and post river centerline), sinuosity, slope and lateral sediment deposition were determined for 50km river stretches. Analyzes reveal that flood deposits extend generally less than 2 km from the main channel axis. Furthermore, channel activity correlates negatively with channel sinuosity and lateral distance of sediment deposition and positively with slope. The river channel migrated over 100's of meters during the July 2010 flood event. Lateral migration averaged ~340m along a 1000km stretch of the Indus River over a period of just 52 days. Although this discharge event was not exceptional, lateral migration was significant and deposition impacts the active river floodplain. Remarkably, most sediments are deposited downstream the large

  4. Accumulation of polychlorinated biphenyls in american shad during their migration in the Hudson River, spring 1977.

    PubMed

    Pastel, M; Bush, B; Kim, J S

    1980-06-01

    Fifty-two female American shad (Alosa sapidissima) were collected during the spring of 1977 at two sites on the lower Hudson River, 27 miles and 75 miles from the river mouth. The fish were extracted with hexane, and the extracts were analyzed by electron-capture gas chromatography (EC-GC) and by GC/mass spectrometry (MS), PCBs were quantitated by EC-GC, and the concentrations were compared by fish length and by site. Fish collected from the downstream site contained a mean PCB concentration of 2.0 +/- 1.0 microgram/g, wet weight; fish from the upstream site contained a mean PCB concentration of 6.1 +/- 2.6 microgram/g, wet weight. Aliquots of the hexane extracts were fractionated before analysis by GC/MS. The presence of PCBs was confirmed, and DDE and the alkane series from C22 through C26 were detected. American shad are saltwater fish that only enter fresh water to spawn. Because they do not feed in fresh water before spawning, they may be used as an indicator of water contamination.

  5. Plasma insulin-like growth factor-I concentrations in yearling chinook salmon (Oncorhynchus tshawytscha) migrating from the Snake River Basin, USA

    USGS Publications Warehouse

    Congleton, J.L.; Biga, P.R.; Peterson, B.C.

    2003-01-01

    During the parr-to-smolt transformation (smoltification) of juvenile salmonids, preadaptive changes in osmoregulatory and ionoregulatory ability are regulated in part by the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. If food intake is sufficient, plasma IGF-I increases during smoltification. On the other hand, plasma IGF-I typically decreases in fasting fish and other vertebrate animals. Because food availability is limited for juvenile salmonids undertaking an extended 6- to 12-week spring migration to and through the Snake-Columbia River hydropower system (northwestern USA), IGF-I concentrations might be expected to decrease, potentially compromising seawater tolerance. To address this possibility, yearling chinook salmon Oncorhynchus tshawytscha reared in three Snake River Basin hatcheries were sampled before release and at two downstream dams. Dry masses of migrating fish either did not increase during the migration (in 2000, an average-flow year), or decreased significantly (in 2001, a low-flow year). In both years, plasma IGF-I levels were significantly higher (1.6-fold in 2000, 3.7-fold in 2001) for fish sampled at the last dam on the lower Columbia River than for fish sampled prior to release. Plasma IGF-I concentrations in migrating fish may, nonetheless, have been nutritionally down-regulated to some degree, because plasma IGF-I concentrations in juvenile chinook salmon captured at a Snake River dam and transported to the laboratory increased in fed groups, but decreased in unfed groups. The ability of migrating smolts to maintain relatively elevated IGF-I levels despite restricted food intake and loss of body mass is likely related to smoltification-associated changes in hormonal balance. ?? 2004 Kluwer Academic Publishers.

  6. Movements and Distribution of Northern Squawfish Downstream of Lower Snake River Dams Relative to the Migration of Juvenile Salmonids, 1992-1993 Completion Report.

    SciTech Connect

    Isaak, D.J.; Bjornn, T.C.

    1996-03-01

    Northern squawfish Ptychocheilus oregonensis movements were monitored downstream of two lower Snake River dams during the juvenile salmonid migrations of 1992 and 1993. During a high flow year in 1993, the abundance of squawfish in the tailrace of Lower Granite Dam peaked in July, after the majority of juveniles had moved past Lower Granite Dam, and peak abundance was inversely related to river discharge. Few squawfish moved into the tailrace of Ice Harbor Dam in 1993 because of the extended period of spill. Distributions of squawfish in the tailrace of Lower Granite Dam varied between and within years and shifted in response to changing prey densities, flow patterns, water temperature, and diel cycles, but fish consistently used low velocity habitats. Data from Ice Harbor Dam is less extensive, but squawfish distributions there appeared to be affected by changing flow patterns and fish used low velocity habitats. The changes in distribution and abundance of squawfish in tailrace areas are evidence that predation on seaward migrating salmonids depends on the timing of migration and size and timing of runoff. Juvenile salmonids migrating in the spring and early summer will probably be less affected by squawfish predation in tailrace areas than salmon that migrate later in the summer.

  7. Determination of Swimming Speeds and Energetic Demands of Upriver Migrating Fall Chinook Salmon (Oncorhynchus tshawytscha) in the Klickitat River, Washington

    SciTech Connect

    Brown, Richard S.; Geist, David R.

    2002-07-01

    This report describes a field study by PNNL for Bonneville Power Administration in fall 2001 to study the migration and energy use of adult fall chinook salmon traveling up the Klickitat River to spawn. The salmon were tagged with surgically implanted electromyogram transmitters or gastrically implanted coded transmitters. Swim speed and aerobic and anaerobic energy use were determined for the fish as they attempted to pass three waterfalls on the lower Klickitat and as they traversed free-flowing stretches between and below the falls. Of the 35 EMG-tagged fish released near the mouth of the Klickitat, 40% passed the first falls, 36% passed the second falls, and 20% reached Lyle Falls but were unable to leap over. Mean swimming speeds ranged from as low as 52.6 cm/sec between falls to as high as 158.1 cm/sec at falls passage. Fish exhibited a higher percentage of occurrences of burst swimming while passing the falls than while between falls (58.9% versus 1.7%). However, fish expended more energy swimming the stretches between the falls than during actual falls passage (52.3-236.2 kcals versus 0.3-1.1 kcals). Male-female and day-night differences in falls passage success were noted. PNNL also examined energy costs and swimming speeds for fish released above Lyle Falls as they migrated to upstream spawning areas. This journey averaged 15.93 days at a mean rate of 2.36 km/day to travel a mean maximum of 37.6 km upstream at a total energy cost of approx 4,492 kcals (32% anaerobic/68% aerobic). When the salmon have expended the estimated 968 kcals needed to get through Bonneville Dam and the three falls on the Lower Klickitat, plus this 4,492 kcals to reach the spawning grounds, they are left with approximately 8 to 12% (480 to 742 kcals) of their energy reserves for spawning. A delay of 4 to 7 days along the lower Klickitat River could deplete their remaining energy reserves (at a rate of about 103 kcals/day), resulting in death before spawning would occur.

  8. Employing the Hilbert-Huang Transform to analyze observed natural complex signals: Calm wind meandering cases

    NASA Astrophysics Data System (ADS)

    Martins, Luis Gustavo Nogueira; Stefanello, Michel Baptistella; Degrazia, Gervásio Annes; Acevedo, Otávio Costa; Puhales, Franciano Scremin; Demarco, Giuliano; Mortarini, Luca; Anfossi, Domenico; Roberti, Débora Regina; Denardin, Felipe Costa; Maldaner, Silvana

    2016-11-01

    In this study we analyze natural complex signals employing the Hilbert-Huang spectral analysis. Specifically, low wind meandering meteorological data are decomposed into turbulent and non turbulent components. These non turbulent movements, responsible for the absence of a preferential direction of the horizontal wind, provoke negative lobes in the meandering autocorrelation functions. The meandering characteristic time scales (meandering periods) are determined from the spectral peak provided by the Hilbert-Huang marginal spectrum. The magnitudes of the temperature and horizontal wind meandering period obtained agree with the results found from the best fit of the heuristic meandering autocorrelation functions. Therefore, the new method represents a new procedure to evaluate meandering periods that does not employ mathematical expressions to represent observed meandering autocorrelation functions.

  9. Comparative evaluation of molecular diagnostic tests for Nucleospora salmonis and prevalence in migrating juvenile salmonids from the Snake River, USA.

    PubMed

    Badil, Samantha; Elliott, Diane G; Kurobe, Tomofumi; Hedrick, Ronald P; Clemens, Kathy; Blair, Marilyn; Purcell, Maureen K

    2011-03-01

    Nucleospora salmonis is an intranuclear microsporidian that primarily infects lymphoblast cells and contributes to chronic lymphoblastosis and a leukemia-like condition in a range of salmonid species. The primary goal of this study was to evaluate the prevalence of N. salmonis in out-migrating juvenile hatchery and wild Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss from the Snake River in the U.S. Pacific Northwest. To achieve this goal, we first addressed the following concerns about current molecular diagnostic tests for N. salmonis: (1) nonspecific amplification patterns by the published nested polymerase chain reaction (nPCR) test, (2) incomplete validation of the published quantitative PCR (qPCR) test, and (3) whether N. salmonis can be detected reliably from nonlethal samples. Here, we present an optimized nPCR protocol that eliminates nonspecific amplification. During validation of the published qPCR test, our laboratory developed a second qPCR test that targeted a different gene sequence and used different probe chemistry for comparison purposes. We simultaneously evaluated the two different qPCR tests for N. salmonis and foundthat both assays were highly specific, sensitive, and repeatable. The nPCR and qPCR tests had good overall concordance when DNA samples derived from both apparently healthy and clinically diseased hatchery rainbow trout were tested. Finally, we demonstrated that gill snips were a suitable tissue for nonlethal detection of N. salmonis DNA in juvenile salmonids. Monitoring of juvenile salmonid fish in the Snake River over a 3-year period revealed low prevalence of N. salmonis in hatchery and wild Chinook salmon and wild steelhead but significantly higher prevalence in hatchery-derived steelhead. Routine monitoring of N. salmonis is not performed for all hatchery steelhead populations. At present, the possible contribution of this pathogen to delayed mortality of steelhead has not been determined.

  10. Comparative evaluation of molecular diagnostic tests for Nucleospora salmonis and prevalence in migrating juvenile salmonids from the Snake River, USA

    USGS Publications Warehouse

    Badil, Samantha; Elliott, Diane G.; Kurobe, Tomofumi; Hedrick, Ronald P.; Clemens, Kathy; Blair, Marilyn; Purcell, Maureen K.

    2011-01-01

    Nucleospora salmonis is an intranuclear microsporidian that primarily infects lymphoblast cells and contributes to chronic lymphoblastosis and a leukemia-like condition in a range of salmonid species. The primary goal of this study was to evaluate the prevalence of N. salmonis in out-migrating juvenile hatchery and wild Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss from the Snake River in the U.S. Pacific Northwest. To achieve this goal, we first addressed the following concerns about current molecular diagnostic tests for N. salmonis: (1) nonspecific amplification patterns by the published nested polymerase chain reaction (nPCR) test, (2) incomplete validation of the published quantitative PCR (qPCR) test, and (3) whether N. salmonis can be detected reliably from nonlethal samples. Here, we present an optimized nPCR protocol that eliminates nonspecific amplification. During validation of the published qPCR test, our laboratory developed a second qPCR test that targeted a different gene sequence and used different probe chemistry for comparison purposes. We simultaneously evaluated the two different qPCR tests for N. salmonis and found that both assays were highly specific, sensitive, and repeatable. The nPCR and qPCR tests had good overall concordance when DNA samples derived from both apparently healthy and clinically diseased hatchery rainbow trout were tested. Finally, we demonstrated that gill snips were a suitable tissue for nonlethal detection of N. salmonis DNA in juvenile salmonids. Monitoring of juvenile salmonid fish in the Snake River over a 3-year period revealed low prevalence of N. salmonis in hatchery and wild Chinook salmon and wild steelhead but significantly higher prevalence in hatchery-derived steelhead. Routine monitoring of N. salmonis is not performed for all hatchery steelhead populations. At present, the possible contribution of this pathogen to delayed mortality of steelhead has not been determined.

  11. Gravel-bed deposition and erosion by bedform migration observed ultrasonically during storm flow, North Fork Toutle River, Washington

    NASA Astrophysics Data System (ADS)

    Dinehart, Randy L.

    1992-08-01

    Ultrasonic depth sounding provides useful and unexpected information about peak discharge and sediment transport when applied during storm flow in channels with erodible beds. Streambed elevation was measured with dual ultrasonic depth sounders during the rise, crest, and recession of a storm flow in the North Fork Toutle River, Washington, on 3 December 1987. The sounder transducers were held in the flow on a rigid pipe which was suspended from a boom over the channel thalweg. The 12 h episode of depth sounding detected the superposition of fine-gravel dunes on large bed waves, the depth-limited growth of mean dune heights from 13 to 25 cm, and bedform-related deposition and erosion in the channel thalweg. The streambed elevation rose 0.3 m in 2 h with increasing stream discharge. Dune heights diminished for about an hour before the peak river stage was attained. Scour of the streambed continued through the peak stage and recession, with 0.7 m of scour over 10 h. Rapid scour of the streambed produced a falling stage while discharge was still rising. Dune heights grew as flow depth increased after peak stage. Streambed elevation was lowered as large bed waves of fine gravel migrated along the thalweg with successively lower troughs leading each bed wave. Bed elevation records from the dual depth sounders were used to calculate dune celerities of 3-6 cm s -1 and bedform wavelengths of 2-11 m. The large bed waves were subtle, dune-like gravel bedforms with wavelengths of 25-30 m. The celerities and bedform dimensions yielded bedform transport weight rates between 3 and 20 kg s -1 m -1 and grain shear stresses between 40 and 100 N m -2 for the depth-sounding episode.

  12. Influence of Riparian Tree Phenology on Lower Colorado River Spring-Migrating Birds: Implications of Flower Cueing

    USGS Publications Warehouse

    McGrath, Laura J.; van Riper, Charles

    2005-01-01

    Executive Summary Neotropical migrant birds make choices about which habitats are most likely to provide successful foraging locations during migration, but little is known about how these birds recognize and process environmental clues that indicate the presence of prey species. Aspects of tree phenology, notably flowering of trees along the lower Colorado River corridor, coincide with the migratory stopovers of leaf-gleaning insectivorous songbirds and may be an important indicator of arthropod prey species availability. Shifting tree flowering and leaf flush during the spring migration period presents avian insectivores with an assortment of foraging opportunities. During two field seasons at Cibola National Wildlife Refuge in southwestern Arizona, we examined riparian tree species to test whether leaf-gleaning insectivorous birds are attracted to the flowering condition of trees in choosing foraging sites. We predicted that flowering trees would host more insect prey resources, would thus show increased visit rates, length of stays and attack ratios of migrant avian insectivores, and that those arthropods would be found in the stomach contents of the birds. Paired trees of honey mesquite (Prosopis glandulosa), displaying heavy and light degrees of flowering were observed to test these predictions. To test whether birds are tracking arthropods directly or are using flowers as a proximate cue, we removed flowers from selected trees and paired these treated trees with neighboring high flowering trees, which served as controls. Avian foraging behavior, avian diets, arthropods, and phenology data were collected at the same time to control for temporal differences in insect availability, plant phenology, and differences in stopover arrivals of birds. We documented five patterns from this study: 1) Higher abundance and richness of arthropods were found on honey mesquite trees with greater numbers of flowers. 2) Arthropod abundance and richness increased as flowering

  13. Instream Flows Needed for Successful Migration Spawning and Rearing of Rainbow and Westslope Cutthroat Trout in Selected Tributaries of the Kootenai River: Final Report 1986.

    SciTech Connect

    Marotz, Brian

    1986-12-01

    This study was conducted by Montana Department of Fish, Wildlife and Parks in contractual agreement with Bonneville Power Administration and addresses measure 804(a)(9) of the Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program. Objectives were to determine instream flow needs in Kootenai River tributaries to maintain successful fish migration, spawning and rearing habitat of game fish, evaluate existing resident and rearing fish populations, and compile hydrologic and fishery information required to secure legal reservation of water for the fishery resource.

  14. The feasibility of population migration from arid mountainous areas of Central Gansu to the oasis west of the Yellow River in the province.

    PubMed

    Chen, B; Zhang, Z; Yuan, H

    1991-01-01

    This article on population migration from Central Gansu, China, which is made up of 18 impoverished counties in Dingxi Region, to Hexi in the Yellow River Valley focuses on the basic mechanisms and characteristics of population migration, the effects of migration on adaptability, the return rate, and the socioeconomic and ecological benefits of migration. Analysis is based on logical deduction and empirical evidence. The reasons for migration are poverty and unchecked population growth. Population in Central Gansu doubled (110.1%) between 1952-83, while the population in the province increased 86.67% and in the country 83.52%. Per capita grain allocations in Dingxi and the marginal utility of agricultural production declined. Population pressure led to short supplies of food and fuel and excessive land reclamation, which produced soil erosion, and a downward spiral. Migrants were attracted to Hexi because of favorable farming conditions and a developed economy. Subsidies were used to encourage people to migrate voluntarily. 31,485 people migrated to the Hexi Corridor in 1988. 4450 came from Huining County and 3743 from Dingxi. Most went to Jiuquan (17,490 people), and 7,357 migrated to Zhongye, both areas with good irrigation facilities. 78.33% of the migrants were individually placed and 21.67% were placed as groups in "hanging" villages of 320/village. The inter-regional migration rate was 85.27% between 1983-86 in Jiuquan region, or 14,000 people. Migrants found their living conditions to be greatly improved. Per capita income increased 12.8 times from 497.5 yuan in 1983, while the income of nonmigrants underwent only a 4.45-fold increase. There were also differences in grain allocation. Jiuquan had a low return migration rate of 14.73% between 1983-86. Variations occur from region to region due to excessive economic disparity, incomplete basic facilities, and forced group migration. The annual yield of investment in migration was 19.87%, which makes the

  15. Fluvial process and morphology of the Brahmaputra River in Assam, India

    NASA Astrophysics Data System (ADS)

    Sarma, J. N.

    2005-09-01

    The Brahmaputra River finds its origin in the Chema Yundung glacier of Tibet and flows through India and Bangladesh. The slope of the river decreases suddenly in front of the Himalayas and results in the deposition of sediment and a braided channel pattern. It flows through Assam, India, along a valley comprising its own Recent alluvium. In Assam the basin receives 300 cm mean annual rainfall, 66-85% of which occurs in the monsoon period from June through September. Mean annual discharge at Pandu for 1955-1990 is 16,682.24 m 3 s - 1. Average monthly discharge is highest in July (19%) and lowest in February (2%). Most hydrographs exhibit multiple flood peaks occurring at different times from June to September. The mean annual suspended sediment load is 402 million tons and average monthly sediment discharge is highest in June (19.05%) and lowest in January (1.02%). The bed load at Pandu was found to be 5-15% of the total load of the river. Three kinds of major geomorphic units are found in the basin. The river bed of the Brahmaputra shows four topographic levels, with increasing height and vegetation. The single first order primary channels of this braided river split into two or more smaller second order channels separated by bars and islands. The second order channels are of three kinds. The maximum length and width of the bars in the area under study are 18.43 km and 6.17 km, respectively. The Brahmaputra channel is characterised by mid-channel bars, side bars, tributary mouth bars and unit bars. The geometry of meandering tributary rivers shows that the relationship between meander wavelength and bend radius is most linear. The Brahmaputra had been undergoing overall aggradation by about 16 cm during 1971 to 1979. The channel of the Brahmaputra River has been migrating because of channel widening and avulsion. The meandering tributaries change because of neck cut-off and progressive shifting at the meander bends. The braiding index of the Brahmaputra has been

  16. Effectiveness of an electrical barrier in blocking a sea lamprey spawning migration on the Jordan River, Michigan

    USGS Publications Warehouse

    Swink, William D.

    1999-01-01

    Mark-recapture studies indicated that a pulsed-DC electrical barrier set to a 2-ms pulse width and 10 pulses/s completely blocked the spawning migration of sea lampreys Petromyzon marinus in the Jordan River, Michigan. Capture efficiency of fyke nets averaged 24% for four groups, about 300 tagged sea lampreys each, released upstream of the barrier; no unmarked sea lampreys and none of the 1,194 sea lampreys tagged and released downstream of the barrier were captured in the fyke nets while the barrier was energized. At a lower pulsator setting (1-ms pulse width; 10 pulses/s), 1 of 900 sea lampreys released below the barrier was recaptured in the nets. Sea lampreys from downstream were captured in the fyke nets after the barrier was de-energized, indicating that the barrier should remain in operation later than mid-July. Both sea lampreys and teleosts exposed to the electrical field were stunned but exhibited no apparent damage at either barrier setting. The pulsed-DC electrical barrier should help reduce the use of chemical lampricides for controlling sea lampreys in some Great Lakes streams and would be particularly suited for streams where even the smallest low-head barrier would create an unacceptably large impoundment.

  17. Low-frequency meandering piezoelectric vibration energy harvester.

    PubMed

    Berdy, David F; Srisungsitthisunti, Pornsak; Jung, Byunghoo; Xu, Xianfan; Rhoads, Jeffrey F; Peroulis, Dimitrios

    2012-05-01

    The design, fabrication, and characterization of a novel low-frequency meandering piezoelectric vibration energy harvester is presented. The energy harvester is designed for sensor node applications where the node targets a width-to-length aspect ratio close to 1:1 while simultaneously achieving a low resonant frequency. The measured power output and normalized power density are 118 μW and 5.02 μW/mm(3)/g(2), respectively, when excited by an acceleration magnitude of 0.2 g at 49.7 Hz. The energy harvester consists of a laser-machined meandering PZT bimorph. Two methods, strain-matched electrode (SME) and strain-matched polarization (SMP), are utilized to mitigate the voltage cancellation caused by having both positive and negative strains in the piezoelectric layer during operation at the meander's first resonant frequency. We have performed finite element analysis and experimentally demonstrated a prototype harvester with a footprint of 27 x 23 mm and a height of 6.5 mm including the tip mass. The device achieves a low resonant frequency while maintaining a form factor suitable for sensor node applications. The meandering design enables energy harvesters to harvest energy from vibration sources with frequencies less than 100 Hz within a compact footprint.

  18. Upstream Material Accumulation and Meandering on Present Day Gully Evolution

    NASA Astrophysics Data System (ADS)

    Pasquon, K.; Gargani, J.; Massé, M.; Conway, S. J.; Vincendon, M.; Séjourné, A.

    2016-09-01

    Here we show the present day evolution of a martian gully during the last 4 MY: (1) non-seasonal material accumulation in the alcove, (2) seasonal evolution of meanders, (3) extension of the channel, (4) significant modifications of the debris apron.

  19. Changes in meandering of the Northern Hemisphere circulation

    NASA Astrophysics Data System (ADS)

    Di Capua, Giorgia; Coumou, Dim

    2016-09-01

    Strong waves in the mid-latitude circulation have been linked to extreme surface weather and thus changes in waviness could have serious consequences for society. Several theories have been proposed which could alter waviness, including tropical sea surface temperature anomalies or rapid climate change in the Arctic. However, so far it remains unclear whether any changes in waviness have actually occurred. Here we propose a novel meandering index which captures the maximum waviness in geopotential height contours at any given day, using all information of the full spatial position of each contour. Data are analysed on different time scale (from daily to 11 day running means) and both on hemispheric and regional scales. Using quantile regressions, we analyse how seasonal distributions of this index have changed over 1979-2015. The most robust changes are detected for autumn which has seen a pronounced increase in strongly meandering patterns at the hemispheric level as well as over the Eurasian sector. In summer for both the hemisphere and the Eurasian sector, significant downward trends in meandering are detected on daily timescales which is consistent with the recently reported decrease in summer storm track activity. The American sector shows the strongest increase in meandering in the warm season: in particular for 11 day running mean data, indicating enhanced amplitudes of quasi-stationary waves. Our findings have implications for both the occurrence of recent cold spells and persistent heat waves in the mid-latitudes.

  20. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2003-2004 Annual Report.

    SciTech Connect

    Smith, Steven G.; Muir, William D.; Zabel, Richard W.

    2004-01-01

    For juvenile chinook salmon Oncorhynchus tshawytscha, sockeye salmon O. nerka, and steelhead O. mykiss that migrate through reservoirs, hydroelectric projects, and free-flowing sections of the Snake and Columbia Rivers, survival estimates are essential to develop effective strategies for recovering depressed stocks. Many management strategies were based on estimates of system survival (Raymond 1979; Sims and Ossiander 1981) derived in a river system considerably different from today's (Williams and Matthews 1995; Williams et al. 2001). Knowledge of the magnitude, locations, and causes of smolt mortality under present passage conditions, and under conditions projected for the future, are necessary to develop strategies that will optimize smolt survival during migration. From 1993 through 2002, the National Marine Fisheries Service (NMFS) and the University of Washington (UW) demonstrated the feasibility of using three statistical models to estimate survival of PIT-tagged (Prentice et al. 1990a) juvenile salmonids passing through Snake River dams and reservoirs (Iwamoto et al. 1994; Muir et al. 1995, 1996, 2001a, 2003; Smith et al. 1998, 2000a,b; Hockersmith et al. 1999; Zabel et al. 2001, 2002). Evaluation of assumptions for these models indicated that all were generally satisfied, and accurate and precise survival estimates were obtained. In 2003, NMFS and UW completed the eleventh year of the study. Flow levels during the early portion of the 2003 spring migration were similar to 2002, and only slightly higher than in the drought conditions during 2001. However, flow levels were much greater during the later part of the migration in 2003. Spill levels were similar to 2002, much higher than in 2001. Research objectives were to: (1) estimate reach survival and travel time in the Snake and Columbia Rivers throughout the yearling chinook salmon and steelhead migrations; (2) evaluate relationships between survival estimates and migration conditions; and (3) evaluate

  1. Influences of a dam on Atlantic salmon (Salmo salar) upstream migration in the Couesnon River (Mont Saint Michel Bay) using hydroacoustics

    NASA Astrophysics Data System (ADS)

    Martignac, F.; Baglinière, J. L.; Thieulle, L.; Ombredane, D.; Guillard, J.

    2013-12-01

    A dam has been recently modified on the Couesnon River in the vicinity of Mont Saint Michel to control and remove the volume of sediment brought into the bay by tidal waters. This paper shows that this dam has an impact on Atlantic salmon (Salmo salar) migration and that adult fish experience adaptive responses.Upstream migration activities were recorded with a 70 kHz echosounder (SIMRAD EY500 model) during two monitoring programs in 2010 and 2011, combining a total of 172 days of data collection. The echosounder was fixed at an upstream location, 8 km from the dam, and its detection beam capacity was approximately one third of the river's cross sectional area.In addition to the time of year, the upstream direction, swimming speed limit and fish size range were the specific criteria used from our database to efficiently discriminate other fish species from the Atlantic salmon. Among a total of 116,000 fishes counted during the two periods of investigations, 189 salmon were identified using those criteria.This study enabled us to identify the driving factors that influence the salmon migration in this semi-natural environment. There was a significant difference in fish activity when the dam was operating and when the river flow was under "normal" hydraulic conditions.Furthermore, during the opening and closing phases of the dam, the migration activity was scattered during the day, with peak abundance occurring mainly during the beginning of the operating phases. However, during all valve-opening phases, the salmon activity occurred mainly during the night. Therefore, the results suggest that this dam has a strong influence on fish migration activity at this particular location.

  2. Dryland anabranching river morphodynamics: Río Capilla, Salar de Uyuni, Bolivia

    NASA Astrophysics Data System (ADS)

    Li, Jiaguang; Bristow, Charlie S.; Luthi, Stefan M.; Donselaar, Marinus E.

    2015-12-01

    The dryland anabranching river Río Capilla is characterized by nonvegetated and vegetated reaches with prominent channel morphology. To identify the morphodynamics of such dryland anabranching systems and their controls, we investigated the Río Capilla of the southern Altiplano Plateau using high-resolution satellite imagery and field measurements. Comparison of high-resolution satellite data reveals that erosion exceeds deposition for the main channel, accompanied by changes in channel planform, such as meander and channel morphology. On-site surveys combined with high-precision GPS and high-resolution satellite imagery show that channels are characterized by shallowness and poor development of levees. The study area of the Río Capilla is divided into two zones of different slopes: zone 1 with a high slope and zone 2 with a low slope. Zone 1 has a relatively straight main channel with few anabranches and grass-covered banks that are stable despite the high gradient; whereas zone 2 is typified by more anabranches with nonvegetated banks, and the main channel experiences prominent bank accretion and erosion. Excavations show that point-bar deposits are fine-sand-dominated in two reaches and that river banks primarily consist of silt and clay. The limited vegetation cover and abundance of desiccation cracks and macropores make the river bank more erodible leading to pronounced lateral migration in this low-gradient dryland river system. Shallow channels and poor development of levees in combination with in-channel accretionary benches result in frequent overbank flooding, which results in a high density of crevasse splays over unconsolidated river banks and accretionary benches. Connection of headcuts and crevasse channels together with lateral migration and chute channels and reactivation of partially abandoned meanders produces an anabranching pattern in such dryland river systems.

  3. Radiological performance assessment for the E-Area Vaults at the Savannah River Site, Part 1: Simulation of radionuclide migration in the near-field

    SciTech Connect

    Yu, A.D.; Cook, J.R.; Lam, P.S.; Wilhite, E.L.; Smith, C.S.

    1994-02-01

    Two papers presented in this session cover a numerical simulation of radionuclide migration from Savannah River Site`s E-Area Vaults (EAV) to the groundwater. These vaults are constructed below the ground surface and above the historical high water table. This paper covers the simulation of radionuclide migration in the unsaturated zone. A saturated zone model containing aquifers affected by the facility was also developed. The rate (Curies/yr) of radionuclide release to the water table obtained from Part I was used as the source term for the saturated zone model. The migration of 23 key radionuclides for up to two million years was predicted [Westinghouse 1994]. The calculated annual dose of each of the radionuclides due to ingestion of water, based on unit initial inventory, is reported in Part II.

  4. Potential effects of hydroelectric dam development in the Mekong River basin on the migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus) elucidated by otolith microchemistry.

    PubMed

    Fukushima, Michio; Jutagate, Tuantong; Grudpan, Chaiwut; Phomikong, Pisit; Nohara, Seiichi

    2014-01-01

    The migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus), two of the most economically important fish species in the Mekong River, was studied using an otolith microchemistry technique. Fish and river water samples were collected in seven regions throughout the whole basin in Thailand, Laos and Cambodia over a 4 year study period. There was coherence between the elements in the ambient water and on the surface of the otoliths, with strontium (Sr) and barium (Ba) showing the strongest correlation. The partition coefficients were 0.409-0.496 for Sr and 0.055 for Ba. Otolith Sr-Ba profiles indicated extensive synchronized migrations with similar natal origins among individuals within the same region. H. siamensis movement has been severely suppressed in a tributary system where a series of irrigation dams has blocked their migration. H. lobatus collected both below and above the Khone Falls in the mainstream Mekong exhibited statistically different otolith surface elemental signatures but similar core elemental signatures. This result suggests a population originating from a single natal origin but bypassing the waterfalls through a passable side channel where a major hydroelectric dam is planned. The potential effects of damming in the Mekong River are discussed. PMID:25099147

  5. Potential effects of hydroelectric dam development in the Mekong River basin on the migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus) elucidated by otolith microchemistry.

    PubMed

    Fukushima, Michio; Jutagate, Tuantong; Grudpan, Chaiwut; Phomikong, Pisit; Nohara, Seiichi

    2014-01-01

    The migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus), two of the most economically important fish species in the Mekong River, was studied using an otolith microchemistry technique. Fish and river water samples were collected in seven regions throughout the whole basin in Thailand, Laos and Cambodia over a 4 year study period. There was coherence between the elements in the ambient water and on the surface of the otoliths, with strontium (Sr) and barium (Ba) showing the strongest correlation. The partition coefficients were 0.409-0.496 for Sr and 0.055 for Ba. Otolith Sr-Ba profiles indicated extensive synchronized migrations with similar natal origins among individuals within the same region. H. siamensis movement has been severely suppressed in a tributary system where a series of irrigation dams has blocked their migration. H. lobatus collected both below and above the Khone Falls in the mainstream Mekong exhibited statistically different otolith surface elemental signatures but similar core elemental signatures. This result suggests a population originating from a single natal origin but bypassing the waterfalls through a passable side channel where a major hydroelectric dam is planned. The potential effects of damming in the Mekong River are discussed.

  6. Potential Effects of Hydroelectric Dam Development in the Mekong River Basin on the Migration of Siamese Mud Carp (Henicorhynchus siamensis and H. lobatus) Elucidated by Otolith Microchemistry

    PubMed Central

    Fukushima, Michio; Jutagate, Tuantong; Grudpan, Chaiwut; Phomikong, Pisit; Nohara, Seiichi

    2014-01-01

    The migration of Siamese mud carp (Henicorhynchus siamensis and H. lobatus), two of the most economically important fish species in the Mekong River, was studied using an otolith microchemistry technique. Fish and river water samples were collected in seven regions throughout the whole basin in Thailand, Laos and Cambodia over a 4 year study period. There was coherence between the elements in the ambient water and on the surface of the otoliths, with strontium (Sr) and barium (Ba) showing the strongest correlation. The partition coefficients were 0.409–0.496 for Sr and 0.055 for Ba. Otolith Sr-Ba profiles indicated extensive synchronized migrations with similar natal origins among individuals within the same region. H. siamensis movement has been severely suppressed in a tributary system where a series of irrigation dams has blocked their migration. H. lobatus collected both below and above the Khone Falls in the mainstream Mekong exhibited statistically different otolith surface elemental signatures but similar core elemental signatures. This result suggests a population originating from a single natal origin but bypassing the waterfalls through a passable side channel where a major hydroelectric dam is planned. The potential effects of damming in the Mekong River are discussed. PMID:25099147

  7. Turbulent large-scale structure effects on wake meandering

    NASA Astrophysics Data System (ADS)

    Muller, Y.-A.; Masson, C.; Aubrun, S.

    2015-06-01

    This work studies effects of large-scale turbulent structures on wake meandering using Large Eddy Simulations (LES) over an actuator disk. Other potential source of wake meandering such as the instablility mechanisms associated with tip vortices are not treated in this study. A crucial element of the efficient, pragmatic and successful simulations of large-scale turbulent structures in Atmospheric Boundary Layer (ABL) is the generation of the stochastic turbulent atmospheric flow. This is an essential capability since one source of wake meandering is these large - larger than the turbine diameter - turbulent structures. The unsteady wind turbine wake in ABL is simulated using a combination of LES and actuator disk approaches. In order to dedicate the large majority of the available computing power in the wake, the ABL ground region of the flow is not part of the computational domain. Instead, mixed Dirichlet/Neumann boundary conditions are applied at all the computational surfaces except at the outlet. Prescribed values for Dirichlet contribution of these boundary conditions are provided by a stochastic turbulent wind generator. This allows to simulate large-scale turbulent structures - larger than the computational domain - leading to an efficient simulation technique of wake meandering. Since the stochastic wind generator includes shear, the turbulence production is included in the analysis without the necessity of resolving the flow near the ground. The classical Smagorinsky sub-grid model is used. The resulting numerical methodology has been implemented in OpenFOAM. Comparisons with experimental measurements in porous-disk wakes have been undertaken, and the agreements are good. While temporal resolution in experimental measurements is high, the spatial resolution is often too low. LES numerical results provide a more complete spatial description of the flow. They tend to demonstrate that inflow low frequency content - or large- scale turbulent structures - is

  8. Distribution and Joint Fish-Tag Survival of Juvenile Chinook Salmon Migrating through the Sacramento-San Joaquin River Delta, California, 2008

    USGS Publications Warehouse

    Holbrook, Christopher M.; Perry, Russell W.; Adams, Noah S.

    2009-01-01

    Acoustic telemetry was used to obtain the movement histories of 915 juvenile fall-run Chinook salmon (Oncorhynchus tshawytscha) through the lower San Joaquin River and Sacramento-San Joaquin Delta, California, in 2008. Data were analyzed within a release-recapture framework to estimate survival, route distribution, and detection probabilities among three migration pathways through the Delta. The pathways included the primary route through the San Joaquin River and two less direct routes (Old River and Turner Cut). Strong inferences about survival were limited by premature tag failure, but estimates of fish distribution among migration routes should be unaffected by tag failure. Based on tag failure tests (N = 66 tags), we estimated that only 55-78 percent of the tags used in this study were still functioning when the last fish was detected exiting the study area 15 days after release. Due to premature tag failure, our 'survival' estimates represent the joint probability that both the tag and fish survived, not just survival of fish. Low estimates of fish-tag survival could have been caused by fish mortality or fish travel times that exceeded the life of the tag, but we were unable to differentiate between the two. Fish-tag survival through the Delta (from Durham Ferry to Chipps Island by all routes) ranged from 0.05 +or- 0.01 (SE) to 0.06 +or- 0.01 between the two weekly release groups. Among the three migration routes, fish that remained in the San Joaquin River exhibited the highest joint fish-tag survival (0.09 +or- 0.02) in both weeks, but only 22-33 percent of tagged fish used this route, depending on the week of release. Only 4-10 percent (depending on week) of tagged fish traveled through Turner Cut, but no tagged fish that used this route were detected exiting the Delta. Most fish (63-68 percent, depending on week of release) migrated through Old River, but fish-tag survival through this route (0.05 +or- 0.01) was only about one-half that of fish that

  9. Use of Aquaculture Ponds and Other Habitats by Autumn Migrating Shorebirds Along the Lower Mississippi River

    NASA Astrophysics Data System (ADS)

    Lehnen, Sarah E.; Krementz, David G.

    2013-08-01

    Populations of many shorebird species are declining; habitat loss and degradation are among the leading causes for these declines. Shorebirds use a variety of habitats along interior migratory routes including managed moist soil units, natural wetlands, sandbars, and agricultural lands such as harvested rice fields. Less well known is shorebird use of freshwater aquaculture facilities, such as commercial cat- and crayfish ponds. We compared shorebird habitat use at drained aquaculture ponds, moist soil units, agricultural areas, sandbars and other natural habitat, and a sewage treatment facility in the in the lower Mississippi River Alluvial Valley (LMAV) during autumn 2009. Six species: Least Sandpiper ( Calidris minutilla), Killdeer ( Charadrius vociferous), Semipalmated Sandpiper ( Calidris pusilla), Pectoral Sandpiper ( C. melanotos), Black-necked Stilt ( Himantopus himantopus), and Lesser Yellowlegs ( Tringa flavipes), accounted for 92 % of the 31,165 individuals observed. Sewage settling lagoons (83.4, 95 % confidence interval [CI] 25.3-141.5 birds/ha), drained aquaculture ponds (33.5, 95 % CI 22.4-44.6 birds/ha), and managed moist soil units on public lands (15.7, CI 11.2-20.3 birds/ha) had the highest estimated densities of shorebirds. The estimated 1,100 ha of drained aquaculture ponds available during autumn 2009 provided over half of the estimated requirement of 2,000 ha by the LMAV Joint Venture working group. However, because of the decline in the aquaculture industry, autumn shorebird habitats in the LMAV may be limited in the near future. Recognition of the current aquaculture habitat trends will be important to the future management activities of federal and state agencies. Should these aquaculture habitat trends continue, there may be a need for wildlife biologists to investigate other habitats that can be managed to offset the current and expected loss of aquaculture acreages. This study illustrates the potential for freshwater aquaculture to

  10. Use of aquaculture ponds and other habitats by autumn migrating shorebirds along the lower Mississippi river.

    PubMed

    Lehnen, Sarah E; Krementz, David G

    2013-08-01

    Populations of many shorebird species are declining; habitat loss and degradation are among the leading causes for these declines. Shorebirds use a variety of habitats along interior migratory routes including managed moist soil units, natural wetlands, sandbars, and agricultural lands such as harvested rice fields. Less well known is shorebird use of freshwater aquaculture facilities, such as commercial cat- and crayfish ponds. We compared shorebird habitat use at drained aquaculture ponds, moist soil units, agricultural areas, sandbars and other natural habitat, and a sewage treatment facility in the in the lower Mississippi River Alluvial Valley (LMAV) during autumn 2009. Six species: Least Sandpiper (Calidris minutilla), Killdeer (Charadrius vociferous), Semipalmated Sandpiper (Calidris pusilla), Pectoral Sandpiper (C. melanotos), Black-necked Stilt (Himantopus himantopus), and Lesser Yellowlegs (Tringa flavipes), accounted for 92 % of the 31,165 individuals observed. Sewage settling lagoons (83.4, 95 % confidence interval [CI] 25.3-141.5 birds/ha), drained aquaculture ponds (33.5, 95 % CI 22.4-44.6 birds/ha), and managed moist soil units on public lands (15.7, CI 11.2-20.3 birds/ha) had the highest estimated densities of shorebirds. The estimated 1,100 ha of drained aquaculture ponds available during autumn 2009 provided over half of the estimated requirement of 2,000 ha by the LMAV Joint Venture working group. However, because of the decline in the aquaculture industry, autumn shorebird habitats in the LMAV may be limited in the near future. Recognition of the current aquaculture habitat trends will be important to the future management activities of federal and state agencies. Should these aquaculture habitat trends continue, there may be a need for wildlife biologists to investigate other habitats that can be managed to offset the current and expected loss of aquaculture acreages. This study illustrates the potential for freshwater aquaculture to

  11. Monitoring the Migrations of Wild Snake River Spring/Summer Chinook Salmon Juveniles, 2007-2008 Report of Research.

    SciTech Connect

    Achord, Stephen; Sandford, Benjamin P.; Hockersmith, Eric E.

    2009-05-26

    This report provides results from an ongoing project to monitor the migration behavior and survival of wild juvenile spring/summer Chinook salmon in the Snake River Basin. Data reported is from detections of PIT tagged fish during late summer 2007 through mid-2008. Fish were tagged in summer 2007 by the National Marine Fisheries Service (NMFS) in Idaho and by the Oregon Department of Fish and Wildlife (ODFW) in Oregon. Our analyses include migration behavior and estimated survival of fish at instream PIT-tag monitors and arrival timing and estimated survival to Lower Granite Dam. Principal results from tagging and interrogation during 2007-2008 are listed below: (1) In July and August 2007, we PIT tagged and released 7,390 wild Chinook salmon parr in 12 Idaho streams or sample areas. (2) Overall observed mortality from collection, handling, tagging, and after a 24-hour holding period was 1.4%. (3) Of the 2,524 Chinook salmon parr PIT tagged and released in Valley Creek in summer 2007, 218 (8.6%) were detected at two instream PIT-tag monitoring systems in lower Valley Creek from late summer 2007 to the following spring 2008. Of these, 71.6% were detected in late summer/fall, 11.9% in winter, and 16.5% in spring. Estimated parr-to-smolt survival to Lower Granite Dam was 15.5% for the late summer/fall group, 48.0% for the winter group, and 58.5% for the spring group. Based on detections at downstream dams, the overall efficiency of VC1 (upper) or VC2 (lower) Valley Creek monitors for detecting these fish was 21.1%. Using this VC1 or VC2 efficiency, an estimated 40.8% of all summer-tagged parr survived to move out of Valley Creek, and their estimated survival from that point to Lower Granite Dam was 26.5%. Overall estimated parr-to-smolt survival for all summer-tagged parr from this stream at the dam was 12.1%. Development and improvement of instream PIT-tag monitoring systems continued throughout 2007 and 2008. (4) Testing of PIT-tag antennas in lower Big Creek during

  12. Comparison of bed form variance spectra within a meander bend during flood and average discharge.

    USGS Publications Warehouse

    Levey, R.A.; Kjerfve, B.; Getzen, R.T.

    1980-01-01

    Time series analysis of streambed elevation in a meander bend along the Congaree River was used to determine the changes in bed form population succeeding a 16-year flood event. Variance spectra computed for a 595m longitudinal profile indicate that: a) the bed form variance for the flood record is significantly greater for all wavelengths from 5 to 30m; b) no well-demarcated bed form classes were present during the survey times, pointing to the possible existence of a continuum of bed form sizes rather than well-defined classes; and c) bed forms produced by the flood discharge were rapidly altered as the stage returned toward average level. -from Authors

  13. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2000 Annual Report.

    SciTech Connect

    Zabel, Richard; Smith, Steven G.; Muir, William D.

    2001-02-01

    In 2000, the National Marine Fisheries Service and the University of Washington completed the eight year of a study to estimate survival of juvenile salmonids (Oncorhynchus spp.) passing through dams and reservoirs on the Snake and Columbia Rivers. A total of 20,313 hatchery steelhead were tagged with passive integrated transpoder (PIT) tags and released at Lower Granite Dam for reach survival estimation. They did not PIT tag any yearlying chinook salmon (O. tshawytscha) for reach survival estimates in 2000 because sufficient numbers for these estimates were available from other studies. Primary research objectives in 2000 were (1) to estimate reach and project survival in the Snake and Columbia Rivers throughout the yearling chinook salmon and steelhead migrations, and (2) to evaluate the survival-estimation models under prevailing conditions. In addition, they estimated survival from point of release to Lower Granite Dam and below for chinook salmon, steelhead, and sockeye salmon (O.nerka) PIT tagged and released at Snake River basin hatcheries and chinook salmon and steelhead PIT tagged and released at Snake River basin hatcheries and chinook salmon and steelhead PIT tagged and released at Snake River basin smolt traps. This report provides reach survival and travel time estimates for 2000 for PIT-tagged yearling chinook salmon and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Results are reported primarily in the form of tables and figures. Further details on methodology and statistical models used are provided in previous reports cited in the text.

  14. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2005-2006 Annual Report.

    SciTech Connect

    Smith, Steven G.; Muir, William D.; Marsh, Douglas M.

    2006-05-01

    In 2005, the National Marine Fisheries Service and the University of Washington completed the thirteenth year of a study to estimate survival and travel time of juvenile salmonids Oncorhynchus spp. passing through dams and reservoirs on the Snake and Columbia Rivers. All estimates were derived from detections of fish tagged with passive integrated transponder tags (PIT tags). We PIT tagged and released a total of 18,439 hatchery steelhead, 5,315 wild steelhead, and 6,964 wild yearling Chinook salmon at Lower Granite Dam in the Snake River. In addition, we utilized fish PIT tagged by other agencies at traps and hatcheries upstream from the hydropower system and at sites within the hydropower system in both the Snake and Columbia Rivers. PIT-tagged smolts were detected at interrogation facilities at Lower Granite, Little Goose, Lower Monumental, Ice Harbor, McNary, John Day, and Bonneville Dams and in the PIT-tag detector trawl operated in the Columbia River estuary. Survival estimates were calculated using a statistical model for tag-recapture data from single release groups (the ''single-release model''). Primary research objectives in 2005 were: (1) Estimate reach survival and travel time in the Snake and Columbia Rivers throughout the migration period of yearling Chinook salmon O. tshawytscha and steelhead O. mykiss. (2) Evaluate relationships between survival estimates and migration conditions. (3) Evaluate the survival estimation models under prevailing conditions. This report provides reach survival and travel time estimates for 2005 for PIT-tagged yearling Chinook salmon (hatchery and wild), hatchery sockeye salmon O. nerka, hatchery coho salmon O. kisutch, and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Additional details on the methodology and statistical models used are provided in previous reports cited here.

  15. Comparison of migration rate and survival between radio-tagged and PIT-tagged migrant yearling chinook salmon in the Snake and Columbia rivers

    USGS Publications Warehouse

    Hockersmith, E.E.; Muir, W.D.; Smith, S.G.; Sandford, B.P.; Perry, R.W.; Adams, N.S.; Rondorf, D.W.

    2003-01-01

    A study was conducted to compare the travel times, detection probabilities, and survival of migrant hatchery-reared yearling chinook salmon Oncorhynchus tshawytscha tagged with either gastrically or surgically implanted sham radio tags (with an imbedded passive integrated transponder [PIT] tag) with those of their cohorts tagged only with PIT tags in the Snake and Columbia rivers. Juvenile chinook salmon with gastrically implanted radio tags migrated significantly faster than either surgically radio-tagged or PIT-tagged fish, while migration rates were similar among surgically radio-tagged and PIT-tagged fish. The probabilities of PIT tag detection at downstream dams varied by less than 5% and were not significantly different among the three groups. Survival was similar among treatments for median travel times of less than approximately 6 d (migration distance of 106 km). However, for both gastrically and surgically radio-tagged fish, survival was significantly less than for PIT-tagged fish, for which median travel times exceeded approximately 10 d (migration distance of 225 km). The results of this study support the use of radio tags to estimate the survival of juvenile chinook salmon having a median fork length of approximately 150 mm (range, 127-285 mm) and a median travel time of migration of less than approximately 6 d.

  16. Molecular Detection of Campylobacter spp. and Fecal Indicator Bacteria during the Northern Migration of Sandhill Cranes (Grus canadensis) at the Central Platte River

    PubMed Central

    Ryu, Hodon; Vogel, Jason; Santo Domingo, Jorge; Ashbolt, Nicholas J.

    2013-01-01

    The risk to human health of the annual sandhill crane (Grus canadensis) migration through Nebraska, which is thought to be a major source of fecal pollution of the central Platte River, is unknown. To better understand potential risks, the presence of Campylobacter species and three fecal indicator bacterial groups (Enterococcus spp., Escherichia coli, and Bacteroidetes) was assayed by PCR from crane excreta and water samples collected during their stopover at the Platte River, Nebraska, in 2010. Genus-specific PCR assays and sequence analyses identified Campylobacter jejuni as the predominant Campylobacter species in sandhill crane excreta. Campylobacter spp. were detected in 48% of crane excreta, 24% of water samples, and 11% of sediment samples. The estimated densities of Enterococcus spp. were highest in excreta samples (mean, 4.6 × 108 cell equivalents [CE]/g), while water samples contained higher levels of Bacteroidetes (mean, 5.1 × 105 CE/100 ml). Enterococcus spp., E. coli, and Campylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus sp. densities (∼3.3 × 105 CE/g) 2 to 4 orders of magnitude higher than those of Bacteroidetes (4.9 × 103 CE/g), E. coli (2.2 × 103 CE/g), and Campylobacter spp. (37 CE/g). Sequencing data for the 16S rRNA gene and Campylobacter species-specific PCR assays indicated that C. jejuni was the major Campylobacter species present in water, sediments, and crane excreta. Overall, migration appeared to result in a significant, but temporary, change in water quality in spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds. PMID:23584775

  17. Molecular detection of Campylobacter spp. and fecal indicator bacteria during the northern migration of sandhill cranes (Grus canadensis) at the central Platte River.

    PubMed

    Lu, Jingrang; Ryu, Hodon; Vogel, Jason; Santo Domingo, Jorge; Ashbolt, Nicholas J

    2013-06-01

    The risk to human health of the annual sandhill crane (Grus canadensis) migration through Nebraska, which is thought to be a major source of fecal pollution of the central Platte River, is unknown. To better understand potential risks, the presence of Campylobacter species and three fecal indicator bacterial groups (Enterococcus spp., Escherichia coli, and Bacteroidetes) was assayed by PCR from crane excreta and water samples collected during their stopover at the Platte River, Nebraska, in 2010. Genus-specific PCR assays and sequence analyses identified Campylobacter jejuni as the predominant Campylobacter species in sandhill crane excreta. Campylobacter spp. were detected in 48% of crane excreta, 24% of water samples, and 11% of sediment samples. The estimated densities of Enterococcus spp. were highest in excreta samples (mean, 4.6 × 10(8) cell equivalents [CE]/g), while water samples contained higher levels of Bacteroidetes (mean, 5.1 × 10(5) CE/100 ml). Enterococcus spp., E. coli, and Campylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus sp. densities (~3.3 × 10(5) CE/g) 2 to 4 orders of magnitude higher than those of Bacteroidetes (4.9 × 10(3) CE/g), E. coli (2.2 × 10(3) CE/g), and Campylobacter spp. (37 CE/g). Sequencing data for the 16S rRNA gene and Campylobacter species-specific PCR assays indicated that C. jejuni was the major Campylobacter species present in water, sediments, and crane excreta. Overall, migration appeared to result in a significant, but temporary, change in water quality in spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds. PMID:23584775

  18. Molecular detection of Campylobacter spp. and fecal indicator bacteria during the northern migration of sandhill cranes (Grus canadensis) at the central Platte River.

    PubMed

    Lu, Jingrang; Ryu, Hodon; Vogel, Jason; Santo Domingo, Jorge; Ashbolt, Nicholas J

    2013-06-01

    The risk to human health of the annual sandhill crane (Grus canadensis) migration through Nebraska, which is thought to be a major source of fecal pollution of the central Platte River, is unknown. To better understand potential risks, the presence of Campylobacter species and three fecal indicator bacterial groups (Enterococcus spp., Escherichia coli, and Bacteroidetes) was assayed by PCR from crane excreta and water samples collected during their stopover at the Platte River, Nebraska, in 2010. Genus-specific PCR assays and sequence analyses identified Campylobacter jejuni as the predominant Campylobacter species in sandhill crane excreta. Campylobacter spp. were detected in 48% of crane excreta, 24% of water samples, and 11% of sediment samples. The estimated densities of Enterococcus spp. were highest in excreta samples (mean, 4.6 × 10(8) cell equivalents [CE]/g), while water samples contained higher levels of Bacteroidetes (mean, 5.1 × 10(5) CE/100 ml). Enterococcus spp., E. coli, and Campylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus sp. densities (~3.3 × 10(5) CE/g) 2 to 4 orders of magnitude higher than those of Bacteroidetes (4.9 × 10(3) CE/g), E. coli (2.2 × 10(3) CE/g), and Campylobacter spp. (37 CE/g). Sequencing data for the 16S rRNA gene and Campylobacter species-specific PCR assays indicated that C. jejuni was the major Campylobacter species present in water, sediments, and crane excreta. Overall, migration appeared to result in a significant, but temporary, change in water quality in spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds.

  19. Pair-Trawl Detection of PIT-Tagged Juvenile Salmonids Migrating in the Columbia River Estuary, 2008 Report of Research.

    SciTech Connect

    Magie, Robert J.; Morris, Matthew S.; Ledgerwood, Richard D.

    2009-06-03

    In 2008, we sampled migrating juvenile Pacific salmonids Oncorhynchus spp. tagged with passive integrated transponder (PIT) tags using a surface pair trawl in the upper Columbia River estuary (rkm 61-83). The cod-end of the trawl was replaced with a cylindrical PIT-tag detection antenna with an 86-cm-diameter fish-passage opening and two detection coils connected in series. The pair trawl was 105 m long with a 91.5-m opening between the wings and a sample depth of 4.9 m. Also during 2008, we finalized the development of a prototype 'matrix' antenna, which was larger than previous antennas by a considerable magnitude. The matrix antenna consisted of 6 coils: a 3-coil front component and a 3-coil rear component, which were separated by 1.5-m of net mesh. The fish-passage opening was 2.5 m wide by 3.0 m tall and was attached to a standard-size pair trawl net. Intermittent sampling with a single crew began on 7 March and targeted yearling Chinook salmon O. tshawytscha and steelhead O. mykiss. Daily sampling using two crews began on 30 April and continued through 14 June; during this period we detected 2.7% of all juvenile salmonids previously detected at Bonneville Dam--a measure of sample efficiency. Sampling with a single crew continued through 20 August and targeted subyearling Chinook salmon. We detected 7,397 yearling Chinook salmon, 2,735 subyearling Chinook salmon, 291 coho salmon O. kisutch, 5,950 steelhead, and 122 sockeye salmon O. nerka in the upper estuary. We deployed the matrix antenna system and the older, cylindrical antenna system (86-cm-diameter fish-passage opening) simultaneously in mid-May 2008 to test matrix detection efficiency. The cylindrical antenna system had been used successfully in 2007 and early 2008. Because distribution of migrating salmonids in the estuary changes rapidly, we felt that a tandem sampling effort between the two systems was the only way to truly evaluate comparative detection efficiency. We deployed both systems within 1

  20. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2001-2002 Annual Report.

    SciTech Connect

    Zabel, Richard; Williams, John G.; Smith, Steven G.

    2002-06-01

    In 2001, the National Marine Fisheries Service and the University of Washington completed the ninth year of a study to estimate survival and travel time of juvenile salmonids (Oncorhynchus spp.) passing through dams and reservoirs on the Snake and Columbia Rivers. All estimates were derived from passive integrated transponder (PIT)-tagged fish. We PIT tagged and released at Lower Granite Dam a total of 17,028 hatchery and 3,550 wild steelhead. In addition, we utilized fish PIT tagged by other agencies at traps and hatcheries upstream of the hydropower system and sites within the hydropower system. PIT-tagged smolts were detected at interrogation facilities at Lower Granite, Little Goose, Lower Monumental, McNary, John Day, and Bonneville Dams and in the PIT-tag detector trawl operated in the Columbia River estuary. Survival estimates were calculated using the Single-Release Model. Primary research objectives in 2001 were to: (1) estimate reach and project survival and travel time in the Snake and Columbia Rivers throughout the yearling chinook salmon and steelhead migrations; (2) evaluate relationships between survival estimates and migration conditions; and (3) evaluate the survival-estimation models under prevailing conditions. This report provides reach survival and travel time estimates for 2001 for PIT-tagged yearling chinook salmon and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Results are reported primarily in the form of tables and figures with a minimum of text. More details on methodology and statistical models used are provided in previous reports cited in the text. Results for summer-migrating chinook salmon will be reported separately.

  1. Evaluation of energy expenditure in adult spring Chinook salmon migrating upstream in the Columbia River Basin: an assessment based on sequential proximate analysis

    USGS Publications Warehouse

    Mesa, M.G.; Magie, C.D.

    2006-01-01

    The upstream migration of adult anadromous salmonids in the Columbia River Basin (CRB) has been dramatically altered and fish may be experiencing energetically costly delays at dams. To explore this notion, we estimated the energetic costs of migration and reproduction of Yakima River-bound spring Chinook salmon Oncorhynchus tshawytscha using a sequential analysis of their proximate composition (i.e., percent water, fat, protein, and ash). Tissues (muscle, viscera, and gonad) were sampled from fish near the start of their migration (Bonneville Dam), at a mid point (Roza Dam, 510 km upstream from Bonneville Dam) and from fresh carcasses on the spawning grounds (about 100 km above Roza Dam). At Bonneville Dam, the energy reserves of these fish were remarkably high, primarily due to the high percentage of fat in the muscle (18-20%; energy content over 11 kJ g-1). The median travel time for fish from Bonneville to Roza Dam was 27 d and ranged from 18 to 42 d. Fish lost from 6 to 17% of their energy density in muscle, depending on travel time. On average, fish taking a relatively long time for migration between dams used from 5 to 8% more energy from the muscle than faster fish. From the time they passed Bonneville Dam to death, these fish, depending on gender, used 95-99% of their muscle and 73-86% of their viscera lipid stores. Also, both sexes used about 32% of their muscular and very little of their visceral protein stores. However, we were unable to relate energy use and reproductive success to migration history. Our results suggest a possible influence of the CRB hydroelectric system on adult salmonid energetics.

  2. An Integrated Sediment Budget for the Le Sueur River in Southern Minnesota

    NASA Astrophysics Data System (ADS)

    Day, S. S.; Belmont, P.; Perg, L.; Johnson, A.; Gran, K.; Jennings, C.; Wilcock, P.

    2007-12-01

    The Le Sueur River is the primary sediment contributor to the Minnesota River, which is impaired by sediment under the Clean Water Act. The necessary first step toward developing a watershed management plan is identifying sediment sources and sinks throughout the basin. The focus of this study is to quantify the contribution of sediment from different sources in order to understand the broader problems affecting the larger Minnesota Basin. The lower Le Sueur River is actively incising in response to late Pleistocene baselevel fall on the Minnesota River, a result of the catastrophic draining of glacial Lake Agassiz. Potential sediment sources along the Le Sueur include high bluffs composed of highly consolidated Pre-Illinoisian, Illinoisian and Wisconsinin till and alluvial sediment, growing ravines and gullies, sediment exchange between the active channel and floodplains, as well as upland agricultural fields, which account for over 90% of the land surface. We applied side-scanning LiDAR to quantify the amount of sediment being eroded from the high bluffs and banks. To understand meander migration rates as well as ravine and gully retreat rates, and to supplement the understanding of bluff retreat rates, we have used aerial LiDAR along with comparative analysis of historic aerial orthophotos. The aerial LiDAR will also be used to calculate the volume of sediment being stored in the floodplains and terraces along the river, which will be used to create a floodplain exchange model. Preliminary results indicate that bluff retreat rates could be as high as 0.4 meters per year and meander bend migration rates up to 3 meters per year in isolated reaches of the watershed. Data collected from each potential source will be combined to create an overall sediment routing model for the watershed.

  3. The geomorphic evolution of Somesu Mic River (Romania) over the past two millenia

    NASA Astrophysics Data System (ADS)

    Persoiu, Ioana; Persoiu, Aurel

    2010-05-01

    In this paper we present the dynamics of Somesu Mic River (NW Romania) in relation with the climatic changes over the past 2000 years. The results and discussions are based on 1) documentary evidences of important floods in the area (starting with 1200 AD), 2) the spatial position of old bridges, roads, human settlements related to river position (from the Roman Epoch though the Medieval Period), 3) historical planform river dynamic, based on successive cartographic maps (past 250 years) and 4) OSL and 14C absolute dating of channel fills exposed in the river's bank. The climate in the area was reconstructed using stable isotopes of oxygen and hydrogen in ice cores retrieved from Scarisoara Ice Cave, which display two colder (and possibly more humid) periods between 400 - 900 AD (dark Ages Cold Period - DACP) and 1300-1850 AD (Little Ice Age - LIA), and two warmer (and possibly drier) periods, between 0-400AD (Roman Warm Period - RWP) and 900-1300 AD (Medieval Warm Period - MWP) Our results shows that during periods with high incidence of important floods (LIA), the river readjusts its planform morphology trough meander cut-offs or avulsions on a larger scale, while during periods of reduced incidence of important floods (RWP and MWP), lateral migration became the main river planform process. This behaviour is complicated by geology, reflected in specific local adjustments (e.g. high planform stability, preferential channel migration, avulsion).

  4. Meandered-line antenna with integrated high-impedance surface.

    SciTech Connect

    Forman, Michael A.

    2010-09-01

    A reduced-volume antenna composed of a meandered-line dipole antenna over a finite-width, high-impedance surface is presented. The structure is novel in that the high-impedance surface is implemented with four Sievenpiper via-mushroom unit cells, whose area is optimized to match the meandered-line dipole antenna. The result is an antenna similar in performance to patch antenna but one fourth the area that can be deployed directly on the surface of a conductor. Simulations demonstrate a 3.5 cm ({lambda}/4) square antenna with a bandwidth of 4% and a gain of 4.8 dBi at 2.5 GHz.

  5. Decay mechanism of the 2004/05 Kuroshio large meander

    NASA Astrophysics Data System (ADS)

    Usui, Norihisa; Tsujino, Hiroyuki; Nakano, Hideyuki; Fujii, Yosuke; Kamachi, Masafumi

    2011-10-01

    The decay mechanism of the 2004/05 Kuroshio large meander (LM) is examined using a data assimilation/prediction system. Assimilation results reveal detailed variations of the Kuroshio path during the LM period. The Kuroshio takes the typical LM in September 2004 to January 2005. The LM then moves eastward and starts crossing the Izu Ridge (IR) in late January 2005. A minor path transition occurs again in June 2005. As a result, the meandering path straddles the IR, and subsequently the meander amplitude decreases rapidly, resulting in the disappearance of the LM. Prediction results suggest that these path transitions are caused by disturbances propagating along the Kuroshio. The assimilation results also indicate that the LM weakens after the first transition in late January 2005 and thus the transition triggers the subsequent LM decay. We propose three possible mechanisms for the weakening of the LM. (1) Extraction of high potential vorticity (PV) water from the LM by disturbances coming from the upstream of the Kuroshio. (2) Generation and propagation of the costal trapped waves, which are induced as a result of interaction of cold eddy of the LM and the IR, and extract potential energy from the LM. (3) Outflow of high-PV water of the LM to the downstream passing through a southern gate of the IR south of Hachijo-jima, which works after the meandering path straddles the IR. The mechanisms 2 and 3 are closely related to the existence of the IR, suggesting that the LM decay is prescribed by the IR.

  6. Effects of stretching on maintaining the Kuroshio meander

    NASA Astrophysics Data System (ADS)

    Kurogi, Masao; Hasumi, Hiroyasu; Tanaka, Yukio

    2013-03-01

    Using a two-way nested-grid ocean general circulation model driven by a repeat annual cycle forcing, the Kuroshio path variation is examined by varying the strength of wind forcing. For climatological or 10% weaker wind forcing, both large-meander (LM) and non-large-meander (NLM) paths alternately appear, with each type of path continuing for a few years to a decade. This timescale and path transition processes are generally consistent with observations. For the LM path, the main balance in the depth-integrated vorticity equation for the upper ocean is shown to be between the beta, advection, and stretching terms. The stretching term is comparable to and has the same sign as the beta term at the western side of the meandering part, indicating that the stretching term has the effects of shortening the wavelength and stabilizing the LM path. The stretching term is mainly determined by downwelling caused by crossing of the upper and deep flows. Contrary to the above two cases, only the NLM path appears for 10% stronger wind forcing. It is suggested that the strength of climatological wind forcing is near the upper limit that allows the LM path to occur. In this study, the control experiment is carried out by choosing parameterizations and parameter values to reproduce the Kuroshio path variation as realistic as possible. Therefore, the results from the two sensitivity experiments are expected to represent a realistic response of the Kuroshio path variation.

  7. Dynamic Gaussian wake meandering in a restricted nonlinear simulation framework

    NASA Astrophysics Data System (ADS)

    Bretheim, Joel; Porte-Agel, Fernando; Gayme, Dennice; Meneveau, Charles

    2015-11-01

    Wake meandering can significantly impact the performance of large-scale wind farms. Simplified wake expansion (e.g., Jensen/PARK) models, which are commonly used in industry, lead to accurate predictions of certain wind farm performance characteristics (e.g., time- and row-averaged total power output). However, they are unable to capture certain temporal phenomena such as wake meandering, which can have profound effects on both power output and turbine loading. We explore a dynamic wake modeling framework based on the approach proposed by Larsen et al. (Wind Energy 11, 2008) whereby turbine ``wake elements'' are treated as passive tracers and advected by an averaged streamwise flow. Our wake elements are treated as Gaussian velocity deficit profiles (Bastankhah and Porte-Agel, Renew. Energy 70, 2014). A restricted nonlinear (RNL) model is used to capture the turbulent velocity fluctuations that are critical to the wake meandering phenomenon. The RNL system, which has been used in prior wall-turbulence studies, provides a computationally affordable way to model atmospheric turbulence, making it more reasonable for use in engineering models than the more accurate but computationally intensive approaches like large-eddy simulation. This work is supported by NSF (IGERT 0801471, SEP-1230788, and IIA-1243482, the WINDINSPIRE project).

  8. Estimations of paleochannel geometry and discharge using Ground Penetrating Radar (GPR) on terraces of the Le Sueur River, south-central Minnesota

    NASA Astrophysics Data System (ADS)

    Targos, C. A.; Gran, K. B.

    2014-12-01

    Paleo channels, preserved on terraces via meander cutoffs during an incisional period, record the channel geometry and thus discharge throughout a river's history. We measured paleochannel geometry on terraces throughout the Le Sueur River in south-central Minnesota, to track how channel geometry has changed throughout the last 13,400 years. A rapid drop in base level 13,400 yr B.P. triggered knickpoint migration and valley incision that is ongoing today. Since the 1800's, the area has developed rapidly with an increase in agriculture and the amount of tile drainage, directly impacting river discharge by increasing water input to the river. Five paleochannels were identified on terraces along the Le Sueur River from 1m-resolution lidar data. Ground Penetrating Radar (GPR) was used to obtain a subsurface image across paleo-meanders to estimate the geometry of paleochannels. By measuring the geometry of paleochannels, we can compare the channel geometry and effective discharge at the time the terrace was being carved to today's conditions. Three lines were run across each paleo-channel perpendicular to the historic water flow. Each of the 15 lines were "processed" using the EKKO Project 2 software supplied by Sensors and Software to sharpen the images, making it easier to identify the paleo channel geometry. OSL samples were collected from overbank deposits to determine the time of channel abandonment. Paleo discharge accompanied with depositional ages provide a history of flow conditions on the Le Sueur River. Preliminary results suggest the river channel has widened and increased in depth with time. This implies that the increase in agriculture and tile drainage since the area's development has negatively impacted the Le Sueur River resulting in a change in channel morphometry more conducive to erosion along the bluffs and banks. This increase in erosion has directly impacted the amount of sediment delivered to the rivers from banks and bluffs, increasing the

  9. Migrational Characteristics, Biological Observations, and Relative Survival of Juvenile Salmonids Entering the Columbia River Estuary, 1966-1983, 1985 Final Report of Research.

    SciTech Connect

    Dawley, Earl M.

    1986-04-01

    Natural runs of salmonids in the Columbia River basin have decreased as a result of hydroelectric-dam development, poor land- and forest-management, and over-fishing. This has necessitated increased salmon culture to assure adequate numbers of returning adults. Hatchery procedures and facilities are continually being modified to improve both the efficiency of production and the quality of juveniles produced. Initial efforts to evaluate changes in hatchery procedures were dependent upon adult contributions to the fishery and returns to the hatchery. Procedures were developed for sampling juvenile salmon and steelhead entering the Columbia River estuary and ocean plume. The sampling of hatchery fish at the terminus of their freshwater migration assisted in evaluating hatchery production techniques and identifying migrational or behavioral characteristics that influence survival to and through the estuary. The sampling program attempted to estimate survival of different stocks and define various aspects of migratory behavior in a large river, with flows during the spring freshet from 4 to 17 thousand cubic meters per second (m/sup 3//second).

  10. Assessing geomorphic sensitivity in relation to river capacity for adjustment

    NASA Astrophysics Data System (ADS)

    Reid, H. E.; Brierley, G. J.

    2015-12-01

    River sensitivity describes the nature and rate of channel adjustments. An approach to analysis of geomorphic river sensitivity outlined in this paper relates potential sensitivity based on the expected capacity of adjustment for a river type to the recent history of channel adjustment. This approach was trialled to assess low, moderate and high geomorphic sensitivity for four different types of river (10 reaches in total) along the Lower Tongariro River, North Island, New Zealand. Building upon the River Styles framework, river types were differentiated based upon valley setting (width and confinement), channel planform, geomorphic unit assemblages and bed material size. From this, the behavioural regime and potential for adjustment (type and extent) were determined. Historical maps and aerial photographs were geo-rectified and the channel planform digitised to assess channel adjustments for each reach from 1928 to 2007. Floodplain width controlled by terraces, exerted a strong influence upon reach scale sensitivity for the partly-confined, wandering, cobble-bed river. Although forced boundaries occur infrequently, the width of the active channel zone is constrained. An unconfined braided river reach directly downstream of the terrace-confined section was the most geomorphically sensitive reach. The channel in this reach adjusted recurrently to sediment inputs that were flushed through more confined, better connected upstream reaches. A meandering, sand-bed river in downstream reaches has exhibited negligible rates of channel migration. However, channel narrowing in this reach and the associated delta indicate that the system is approaching a threshold condition, beyond which channel avulsion is likely to occur. As this would trigger more rapid migration, this reach is considered to be more geomorphically sensitive than analysis of its low migration rate alone would indicate. This demonstrates how sensitivity is fashioned both by the behavioural regime of a reach

  11. Seasonal movements among river reaches, migration strategies, and population structure of the divided Connecticut River shortnose sturgeon population: the effects of Holyoke Dam

    USGS Publications Warehouse

    Kynard, Boyd; Kieffer, Micah; Vinogradov, Phil; Kynard, B.; Bronzi, P.; Rosenthal, H.

    2012-01-01

    Even after 155 years, each population segment seasonally migrates toward the other attempting to maintain the natural connection. Migration timing and style of pre-spawning and post-spawning males and females is discussed, as is homing. The impact of Holyoke Dam on population size and growth is characterized and turbine mortality of adult sturgeon passing through a Kaplan turbine at the dam is estimated. The chapter also identifies a behavioral dysfunction that results when migrations are blocked by a dam and are not completed at the correct stage of life. Many unknown effects of damming on other long-lived riverine fishes are likely captured in this 16-year study.

  12. Topographic steering, flow recirculation, velocity redistribution, and bed topography in sharp meander bends

    NASA Astrophysics Data System (ADS)

    Blanckaert, K.

    2010-09-01

    The bed topography and associated flow field are investigated in a laboratory configuration with parameters that are representative for sharp natural meander bends. Zones of inward mass transport are characterized by a quasi-linear transverse bed profile, whereas zones of outward mass transport, induced by pronounced curvature variations, are characterized by a quasi-horizontal shallow point bar at the inside of the bend, a deep pool at the outside, and an increase in overall cross-sectional area. These quasi-bilinear bed profiles can be attributed to the curvature-induced secondary flow that is confined to the pool. Topographic steering, mainly due to mass conservation, concentrates the major part of the discharge over the deepest zones of the bend. But the pattern of depth-averaged velocities, which is relevant with respect to the development of the bed topography, does not show maximum values over the deepest zones. A term-by-term analysis of the depth-averaged streamwise momentum equation reveals that the water surface gradient is the principal mechanism with respect to flow velocity redistribution, although inertia and secondary flow are also processes of dominant order of magnitude. A required condition for the occurrence of adverse pressure gradients and flow recirculation due to planform curvature variations is established. A different type of flow recirculation, due to a subtle feedback between the flow and the bed topography, occurs over the point bar. The neglect of the influence of vertical velocities impinging on the bed in models for sediment transport is identified as a major shortcoming in the modeling of the morphodynamics of meandering river channels.

  13. Instream Flows Needed for Successful Migration and Rearing of Rainbow and Westslope Cutthroat Trout in Selected Tributaries of the Kootenai River: Final Report FY 1988.

    SciTech Connect

    Marotz, Brian

    1988-06-01

    This is the second phase of a two-part study that was conducted by Montana Department of Fish, Wildlife and Parks in contractual agreement with Bonneville Power Administration to address measures of the Northwest Power Planning Council's River Basin Fish and Wildlife Program. Objectives were to determine instream flow needs in Kootenai River tributaries to maintain successful fish migration, spawning and rearing habitat of game fish, evaluate existing resident and rearing fish populations, and compile hydrologic and fishery information required to secure legal reservation of water for the fishery source. The Kootenai River fishery is threatened by microhydro and other water use development which reduce tributary habitat critical for maintaining a healthy spawning and rearing environment. The wetted perimeter method was used to estimate flows required to maintain existing resident and migratory fish populations in 28 tributaries to the Kootenai River. Migrant passage flows were determined using the discharge-average depth relationship at four (usually five) riffle transects. This information will provide the basis to reserve water through application to the Montana Department of Natural Resources and Conservation. 45 figs., 56 tabs.

  14. Radiological performance assessment for the E-Area Vaults at the Savannah River Site. Part 2, Simulation of contaminant migration in the far-field

    SciTech Connect

    Hiergesell, R.A.; Yu, A.D.; Cook, J.R.; McDowell-Boyer, L.M.; Kearl, P.M.

    1994-03-01

    Two papers presented in this session cover a numerical simulation of radionuclide migration beneath Savannah River Site`s E-Area Vaults (EAV) within the unsaturated and saturated flow fields. This paper (Part II) describes the simulation of radionuclide migration within the saturated zone. Simulations were conducted for 23 radionuclides which are planned to be disposed within the EAV Facility (EAVF). Part I of this study used a nominal starting inventory of 1 Curie for each radionuclide in each group of vaults. Output concentrations from the near-field model were utilized as input for the far-field, or saturated zone transport model. Mechanisms for the migration of radionuclides in the saturated zone are convection and diffusion. Other mechanisms impacting migration of radioisotopes are radioactive decay and adsorption. A partition coefficient (K{sub d}) is used in this model to account for other geochemical effects such as solubility, chemical speciation and colloid formation. Results of simulations indicate that contaminants migrate laterally toward discharge zones at local streams. Groundwater concentrations were calculated for the 23 radionuclides and were converted to doses to man for a groundwater pathway scenario in which an individual ingests 2 liters (L) of groundwater daily. Since calculated doses are in terms of a unit disposal quantity, they will be used to compute the disposal limits for each radionuclide. These limits, and hence the vault loading capacity, will be maximized while maintaining acceptable levels of exposure to individuals exposed through the different pathways. The source term for contaminants at the water table was generated by the vadose zone model described in Part I of this paper and entered as fluxes over time.

  15. Upstream migration of two pre-spawning shortnose sturgeon passed upstream of Pinopolis Dam, Cooper River, South Carolina

    USGS Publications Warehouse

    Finney, S.T.; Isely, J.J.; Cooke, D.W.

    2006-01-01

    Two shortnose sturgeon were artificially passed above the Pinopolis Lock and Dam into the Santee-Cooper Lakes in order to simulate the use of a fish-passage mechanism. Movement patterns and spawning behavior were studied to determine the potential success of future shortnose sturgeon migrations if and when a fish-migration bypass structure is installed. In addition to movement patterns, water temperature was monitored in areas that shortnose sturgeons utilized. Shortnose sturgeon migrated through a large static system to a known shortnose sturgeon spawning area more than 160 km upstream where water temperatures were consistent with known shortnose sturgeon spawning temperatures. No specific movement patterns in the reservoir system were recorded during downstream migrations.

  16. Effects of Iron Gate Dam discharge and other factors on the survival and migration of juvenile coho salmon in the lower Klamath River, northern California, 2006-09

    USGS Publications Warehouse

    Beeman, John; Juhnke, Steven; Stutzer, Greg; Wright, Katrina

    2012-01-01

    Current management of the Klamath River includes prescribed minimum discharges intended partly to increase survival of juvenile coho salmon during their seaward migration in the spring. To determine if fish survival was related to river discharge, we estimated apparent survival and migration rates of yearling coho salmon in the Klamath River downstream of Iron Gate Dam. The primary goals were to determine if discharge at Iron Gate Dam affected coho salmon survival and if results from hatchery fish could be used as a surrogate for the limited supply of wild fish. Fish from hatchery and wild origins that had been surgically implanted with radio transmitters were released into the Klamath River slightly downstream of Iron Gate Dam at river kilometer 309. Tagged fish were used to estimate apparent survival between, and passage rates at, a series of detection sites as far downstream as river kilometer 33. Conclusions were based primarily on data from hatchery fish, because wild fish were only available in 2 of the 4 years of study. Based on an information-theoretic approach, apparent survival of hatchery and wild fish was similar, despite differences in passage rates and timing, and was lowest in the 54 kilometer (km) reach between release and the Scott River. Models representing the hypothesis that a short-term tagging- or handling-related mortality occurred following release were moderately supported by data from wild fish and weakly supported by data from hatchery fish. Estimates of apparent survival of hatchery fish through the 276 km study area ranged from 0.412 (standard error [SE] 0.048) to 0.648 (SE 0.070), depending on the year, and represented an average of 0.790 per 100 km traveled. Estimates of apparent survival of wild fish through the study area were 0.645 (SE 0.058) in 2006 and 0.630 (SE 0.059) in 2009 and were nearly identical to the results from hatchery fish released on the same dates. The data and models examined supported positive effects of water

  17. Ecogeomorphic feedbacks and flood loss of riparian tree seedlings in meandering channel experiments

    NASA Astrophysics Data System (ADS)

    Kui, Li; Stella, John C.; Lightbody, Anne; Wilcox, Andrew C.

    2014-12-01

    During floods, fluvial forces interact with riparian plants to influence evolution of river morphology and floodplain plant community development. Understanding of these interactions, however, is constrained by insufficient precision and control of drivers in field settings, and insufficient realism in laboratory studies. We completed a novel set of flume experiments using woody seedlings planted on a sandbar within an outdoor meandering stream channel. We quantified effects on local sedimentation and seedling loss to scour and burial across realistic ranges of woody plant morphologies (Populus versus Tamarix species), densities (240 plants m-2 versus 24 m-2), and sediment supply (equilibrium versus deficit). Sedimentation was higher within Tamarix patches than Populus patches, reflecting Tamarix's greater crown frontal area and lower maximum crown density. Plant dislodgement occurred rarely (1% of plants) and was induced in plants with shorter roots. Complete burial was most frequent for small Tamarix that occurred at high densities. Burial risk decreased 3% for Populus and 13% for Tamarix for every centimeter increment in stem height, and was very low for plants >50 cm tall. These results suggest that Tamarix are proportionally more vulnerable than Populus when small (<20 cm tall), but that larger plants of both species are resistant to both burial and scour. Thus, plant morphological traits and development windows must be considered in addition to physical drivers when designing process-based restoration efforts on regulated rivers such as flow releases to benefit native tree species.

  18. Competing mechanisms for step meandering in unstable growth

    NASA Astrophysics Data System (ADS)

    Krug, Joachim

    2003-03-01

    In the first part of the talk, recent KMC simulations of the meander instability of a vicinal surface growing under step flow conditions will be described [1]. In the absence of edge diffusion the meander wavelength agrees quantitatively with the continuum linear stability analysis of Bales and Zangwill. In the presence of edge diffusion a local instability mechanism related to the kink rounding barrier E_kr dominates [2], and the meander wavelength is set by one-dimensional nucleation. In both regimes the wavelength can be predicted without adjustable parameters. However, the long time behavior of the meander amplitude does not agree with the predictions of a nonlinear evolution equation [3]. In the second part of the talk, the effect of the kink rounding barrier on equilibrium step edge fluctuations will be explored [4]. When mass transport is through step edge diffusion, the time correlation function of the step fluctuations behaves as C(t) = A(T) t^1/4. At low temperatures the prefactor A(T) shows Arrhenius behavior with an activation energy (E_det + 3 E_k)/4 if E_kr < Ek and (E_det + E_kr + 2 E_k)/4 if E_kr > E_k, where Ek is the kink energy and E_det is the barrier for detachment of a step adatom from a kink. Interpreting results of two experiments on surfaces vicinal to Cu(100) [5] in the light of our theory yields the estimate E_kr = 0.41 eV for the kink rounding barrier at the close packed steps. [1] J. Kallunki, J. Krug and M. Kotrla, Phys. Rev. B 65, 205411 (2002). [2] O. Pierre-Louis, M.R. D'Orsogna and T.L. Einstein, Phys. Rev. Lett. 82, 3661 (1999);P. Politi and J. Krug, Surf. Sci. 446, 89 (2000). [3] J. Kallunki and J. Krug, Phys. Rev. E 62, 6229 (2000). [4] J. Kallunki and J. Krug, Surf. Sci. Lett. (in press). [5] M. Giesen-Seibert, F. Schmitz, R. Jentjens, H. Ibach, Surf. Sci. 329, 47 (1995); T. Maroutian, L. Douillard and H.-J. Ernst, Phys. Rev. B 64, 165401 (2001).

  19. Flow, Morphology and Sedimentology of an Evolving Chute Cutoff on the Wabash River, IL-in.

    NASA Astrophysics Data System (ADS)

    Zinger, J. A.; Best, J.; Rhoads, B. L.; Larson, T. H.

    2014-12-01

    The development of chute cutoffs and the resulting abandonment of meander bends have a substantial influence on the sedimentary dynamics of floodplains. The incision of a chute cutoff channel can rapidly mobilize a large volume of floodplain sediment. On the other hand, bar formation during bend abandonment and the subsequent deposition of sediment within the oxbow lake are key processes in the production of a heterogeneous floodplain sedimentary architecture. This paper describes the evolution of two recent chute cutoffs on the Wabash River, IL-IN. We follow these cutoffs from their initial incision in 2008-2009 through the early stages of bend abandonment. The volume of floodplain sediment mobilized by erosion of the two cutoff channels is estimated using channel bankline positions determined from RTK-GPS surveys and aerial orthophotographs; this flux is then assessed within the context of the sediment mobilized by lateral migration of bends. Repeat bathymetric surveys and aerial photography capture the evolution of bar forms associated with the chute cutoff, and data from ground-penetrating radar reveal the subsurface structure of the complex assemblage of bars that developed as the chute cutoff system shifted from a predominantly erosional to a mixed depositional-erosional phase. These results are combined with knowledge of chute cutoff hydrodynamics to develop an understanding of the dynamics of sediment exchange between river channels and floodplains at evolving meander bend cutoffs.

  20. Survival of Seaward-Migrating PIT and Acoustic-Tagged Juvenile Chinook Salmon in the Snake and Columbia Rivers: An Evaluation of Length-Specific Tagging Effects

    SciTech Connect

    Brown, Richard S.; Oldenburg, Eric W.; Seaburg, Adam; Cook, Katrina V.; Skalski, John R.; Eppard, M. B.; Deters, Katherine A.

    2013-06-12

    Studies examining the survival of juvenile salmon as they emigrate to the ocean provide important information regarding the management of regulated river systems. Acoustic telemetry is a widely used tool for evaluating the behavior and survival of juvenile salmonids in the Columbia River basin. Thus, it is important to understand how the surgical tagging process and the presence of a transmitter affect survival so any biases can be accounted for or eliminated. This study evaluated the effects of fish length and tag type on the survival of yearling and subyearling Chinook salmon during their seaward migrations through the Snake and Columbia rivers during 2006, 2007, and 2008. Fish were collected at Lower Granite Dam on the Snake River (river kilometer 695) and implanted with either only a passive integrated transponder (PIT) tag (PIT fish) or both a PIT tag and an acoustic transmitter (AT fish). Survival was estimated from release at Lower Granite Dam to multiple downstream locations (dams) using the Cormack–Jolly–Seber single release model, and analysis of variance was used to test for differences among length-classes and between tag types. No length-specific tag effect was detected between PIT and AT fish (i.e., length affected the survival of PIT fish in a manner similar to which it affected the survival of AT fish). Survival among the smallest length class (i.e., 80–89 mm) of both PIT and AT subyearling Chinook salmon was markedly low (i.e., 4%). Fish length was positively correlated with the survival of both PIT and AT fish. Significant differences in survival were detected between tag types; the survival of PIT fish was generally greater than that of AT fish. However, confounding variables warrant caution in making strong inferences regarding this factor. Further, results suggest that tag effects may be due to the process of surgically implanting the transmitter rather than the presence of the transmitter.

  1. Effect of low-head lock and dam structures on migration and spawning of American shad and striped bass in the Cape Fear River, North Carolina

    USGS Publications Warehouse

    Smith, Joseph A.; Hightower, Joseph E.

    2012-01-01

    Anadromous fish populations within the Cape Fear River, North Carolina, have declined substantially since the late 1800s. Three low-head lock-and-dam (LD) structures on the river (LD-1–3) contributed to this decline by limiting access to upstream spawning habitat. We used egg sampling and sonic telemetry to examine the effects of the LD structures on migration and spawning activity of American shad Alosa sapidissima and striped bassMorone saxatilis. Egg distribution and stage of development suggested that most of the American shad spawning took place downstream from the lowermost structure, LD-1. The predicted mean density of stage-1 American shad eggs at a water temperature of 21°C was 895 eggs/1,000 m3 (95% credible interval [CI] = 800–994) below LD-1; 147 eggs/1,000 m3 (95% CI = 103–197) below LD-2; and 32 eggs/1,000 m3 (95% CI = 17–49) below the uppermost structure, LD-3. The probability of capturing a stage-1 American shad egg was strongly dependent on water temperature and hour of egg collection. Transmitter detections for 20 sonic-tagged American shad and 20 striped bass in 2008 showed that for both species, the majority of fish moved upstream of LD-1; 35% of American shad and 25% of striped bass migrated upstream of LD-3. Based on passage rates at the three LD structures, American shad would be expected to be most abundant downstream of LD-1 and upstream of LD-3. For striped bass, the river section between LD-2 and LD-3 had the highest egg collections and highest predicted proportion of the run. In combination, these results demonstrate that the locking program provides some access to historical spawning habitat, although further improvements in fish passage could benefit both species.

  2. Gulf Stream Meanders: Observations on Propagation and Growth

    NASA Astrophysics Data System (ADS)

    Watts, D. Randolph; Johns, William E.

    1982-11-01

    We present a new method for continuously tracking the location of the Gulf Stream using a moored array of inverted echo sounders. Time series of lateral displacements of the front, shown accurate to ± 8 km, have been collected along three sections spaced 100, 150, and 200 km downstream (NE) of Cape Hatteras, North Carolina, for a period of 12 months. These records are highly coherent at all periodicities longer than 4 days. From the observed phase lags, a dispersion relationship is presented for the meanders: As the period and wavelength (T, λ) increase from (4 days, 180 km) to (30 days, 600 km), the phase speed decreases smoothly from 40 to 20 km d-1. The meanders exhibited rapid growth at periods longer than 4 days, doubling in variance in each 50-km step downstream. This downstream growth is most appropriately described by a spatial e-folding scale κ-1 ˜400 km for (T, λ) ≲ (9 days, 300 km), and a temporal e-folding scale σ-1 ˜ 6 days for (T, λ) ≳ (14 days, 400 km).

  3. A high performance magnetorheological valve with a meandering flow path

    NASA Astrophysics Data System (ADS)

    Imaduddin, Fitrian; Amri Mazlan, Saiful; Rahman, Mohd Azizi Abdul; Zamzuri, Hairi; Ubaidillah; Ichwan, Burhanuddin

    2014-06-01

    The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment.

  4. Ontogenetic behavior and migration of Dabry's sturgeon, Acipenser dabryanus, from the Yangtze River, with notes on body color and development rate

    USGS Publications Warehouse

    Kynard, B.; Zhuang, P.; Zhang, T.; Zhang, L.

    2003-01-01

    We conducted laboratory experiments with Dabry's sturgeon, Acipenser dabryanus, from the upper Yangtze River to develop a conceptual model of early behavior. We daily observed fish from day-0 (embryo, first life interval after hatching) to day-30 feeding larva for preference of bright habitat and cover, swimming distance above the bottom, up- and down-stream movement, and diel activity. Hatchling to day-12 embryos and days 13-24 larvae were similar for ontogenetic behavior, i.e., neither initiated a dispersal migration, both swam within 15 cm of the bottom, both preferred bright habitat, and neither strongly preferred cover or open habitat. Embryos and larvae were weakly active day and night. Days 72-76 juveniles had a weak nocturnal downstream migration, indicating wild juveniles disperse from a spawning site. In other sturgeon species yet studied representing three genera on three continents, Dabry's sturgeon is the first that does not disperse as an embryo or larva. Development of Dabry's sturgeon is slow, requiring more cumulative temperature degree days per millimeter of larvae TL than is required for other sturgeons to develop into larvae. Thus, a dispersal migration that diverts energy from development may not be adaptive. The available information suggests the initial dispersal of early life intervals is likely done by females, which spawn in a dispersed spawning style, not the usual aggregated spawning style. Juvenile migrants had a black body and tail with a light line along the lateral scutes. The color of juvenile migrants shows that a dark body and tail is characteristic of Acipenser that migrate downstream as larvae or juveniles.

  5. The Use of PIT Tagging to Estimate Juvenile Fall Chinook Salmon Migration Time Through the Priest Rapids Project Area on the Columbia River

    SciTech Connect

    Wahl, R; McMichael, Geoffrey A. )

    2000-12-01

    We are in the process of evaluating how the Priest Rapids Project (PRP, located north of the Hanford reach on the Columbia River) affects populations of wild, fall Chinook salmon that are produced. One part of this project involves using mark-recapture technique to monitor fall juvenile Chinook movement in the area. A passive integrated transponder (PIT) tag technology was used to document migration timing out of the influence of the PRP, and track fish through downstream dams as they make their way to the ocean. On June 6 and 7, 2000, we tagged 1083 fall Chinook sub-yearlings above and below Wanapum Dam, subsequently detecting them as they began to pass through downstream dams. As of 9 August 2000, 122 fish had been detected in one or more of the dams downstream of the PRP. A mean migration time for tagged the fish of 5.5 km/day below the McNary dam and 4.5 km/day above the McNary Dam. The mean migration rate between McNary Dam and John Day Dam was 21.4 km/day. Back calculation, indicated the mean date of departure for juveniles tagged in the pool above Wanapum Dam was July 16, 2000, while juveniles tagged below Wanapum Dam was July 1, 2000. Because fish are still being detected at the dams only preliminary conclusions can be attempted. Since the peak of migration time for these fish seems to have passed, the time when these fish most likely left the PRP area can also be estimated. Data analysis will continue analysis, and hopefully some of the adult returns will be measured as they come through the dams throughout the duration of the project.

  6. Floodplain evolution in a confluence zone: Paraná and Ivaí rivers, Brazil

    NASA Astrophysics Data System (ADS)

    Morais, Eduardo Souza de; Santos, Manoel Luis dos; Cremon, Édipo Henrique; Stevaux, José Cândido

    2016-03-01

    In this study we investigated floodplain development at the confluence of the Paraná and Ivaí rivers, Brazil. We evaluated paleochannels with sedimentary facies and morphometry from cartographic products, which enabled us to identify compartments that indicate homologous morphogenesis. These results contributed to the distinction in the floodplain of areas reworked by the Paraná, Ivaí, or both river systems. Additionally, investigations that included dating deposits on the terrace that borders the floodplain and an alluvial fan (also in contact with the floodplain) reinforced the interpretation of the fluvial landscape. The identified stages of geomorphological evolution demonstrated the existence of a paleoconfluence of the Paraná and Ivaí rivers during the late Pleistocene that was located 6 km upstream from the current confluence. This paleoconfluence displays a different configuration in relation to the current confluence, and its features resemble and contribute to understanding the former braided channel pattern of the Paraná River. The abandonments of the Paraná River channels identified in this study were initial and crucial process in the development of the floodplain. This channel change favored the formation of extensive wetlands and consequently the confluence migration, which resulted in the fluvial reworking indicated by the paleochannels of the Ivaí River. Another implication from the confluence migration was a base level fall, which contributed to maintaining the stability of the Ivaí River and its embedded meanders. In addition, investigations of an alluvial fan in the Paraná River valley provided evidence of massive deposition of sediments from a tributary of the Ivaí River onto the floodplain, which is associated with a regional dry period in the late Holocene as well as neotectonic control.

  7. Meandering right pulmonary vein associated with severe and progressive "idiopathic-like" pulmonary hypertensive vascular disease.

    PubMed

    Cuenca, Sofia; Bret, Montserrat; del Cerro, Maria Jesus

    2016-03-01

    Congenital anomalies of the pulmonary veins are rare. Meandering right pulmonary vein, considered a part of the Scimitar syndrome spectrum, is often an incidental finding during chest imaging. We present the case of a 4-year-old girl diagnosed with meandering pulmonary vein, who developed pulmonary hypertensive disease with an aggressive course, in spite of absence of hypoxia or elevated pulmonary wedge pressure.

  8. Effect of nacelle on wake meandering in a laboratory scale wind turbine using LES

    NASA Astrophysics Data System (ADS)

    Foti, Daniel; Yang, Xiaolei; Guala, Michele; Sotiropoulos, Fotis

    2015-11-01

    Wake meandering, large scale motion in the wind turbine wakes, has considerable effects on the velocity deficit and turbulence intensity in the turbine wake from the laboratory scale to utility scale wind turbines. In the dynamic wake meandering model, the wake meandering is assumed to be caused by large-scale atmospheric turbulence. On the other hand, Kang et al. (J. Fluid Mech., 2014) demonstrated that the nacelle geometry has a significant effect on the wake meandering of a hydrokinetic turbine, through the interaction of the inner wake of the nacelle vortex with the outer wake of the tip vortices. In this work, the significance of the nacelle on the wake meandering of a miniature wind turbine previously used in experiments (Howard et al., Phys. Fluid, 2015) is demonstrated with large eddy simulations (LES) using immersed boundary method with fine enough grids to resolve the turbine geometric characteristics. The three dimensionality of the wake meandering is analyzed in detail through turbulent spectra and meander reconstruction. The computed flow fields exhibit wake dynamics similar to those observed in the wind tunnel experiments and are analyzed to shed new light into the role of the energetic nacelle vortex on wake meandering. This work was supported by Department of Energy DOE (DE-EE0002980, DE-EE0005482 and DE-AC04-94AL85000), and Sandia National Laboratories. Computational resources were provided by Sandia National Laboratories and the University of Minnesota Supercomputing.

  9. Numerical simulation of bar and bank erosion in a vegetated floodplain: A case study in the Otofuke River

    NASA Astrophysics Data System (ADS)

    Iwasaki, Toshiki; Shimizu, Yasuyuki; Kimura, Ichiro

    2016-07-01

    Recent studies suggest that braided river could be single-thread channel by colonization of riparian vegetation; however, this kind of mutual interactions between physical and ecological processes in rivers are still poorly understood. Here we investigate the development of meandering channel in a river, which was originally braided and currently vegetated, the Otofuke River in Japan. The significant morphological processes of this river during a destructive flood event was studied using a two-dimensional morphodynamic model. Using well-calibrated parameters, this model qualitatively reproduced observed morphological changes such as the co-development of sand bars, bar-induced meandering and a chute cutoff. We find that for vegetated channels, meandering could maintain moderate sinuosity; in contrast, in the absence of riparian vegetation, bar-induced meandering channels could become braided. This suggests that distinct meandering channels could be a fundamental channel morphology in the originally braided, but currently vegetated river; however, the simultaneous occurrence of the chute cutoff and meandering indicates that this channel could not be a fully-developed high amplitude meandering channel.

  10. Understanding connectivity of meandering streams and shallow aquifers: Lessons learned from an observational study in northern New Mexico

    NASA Astrophysics Data System (ADS)

    Gomez-Velez, J. D.; Sherson, L. R.; Crossey, L. J.; Dahm, C.; Harvey, J. W.; Wilson, J. L.

    2014-12-01

    The bidirectional feedback between streams and aquifers changes over several spatio- temporal scales, requiring a complex, multi-variable observational network that captures the dominant processes taking place and the response to changes in hydrologic forcing. The importance of stream-aquifer connectivity is evidenced by its influence in the hydrologic response and in the fate and transport of solutes at the watershed scale. To better understand the dynamics of stream-aquifer connectivity and the effects that intra-annual weather variability has on physical and chemical processes, a monitoring network was installed at a meander bend of the East Fork of the Jemez River in the Valles Caldera National Preserve (VCNP), a snow-dominated watershed in northern New Mexico. This work summarizes four years of observations of groundwater-surface water interaction. Spatio-temporal patterns of water level, temperature, and electrical conductivity were measured in meander-bend wells and vertical fluxes to/from the stream were estimated using in-stream piezometers, subsurface thermal records, and distributed temperature sensing in the channel. A three-dimensional numerical model was used to synthesize data and draw general conclusions. The observational network has been collecting data since the summer of 2010 to present, overlapping the Las Conchas fire in the VCNP (largest wildfire on record in New Mexico's history), and therefore representing a valuable data set to evaluate the hydrological and biogeochemical implications of wildfire events.

  11. Movement and spawning of American shad transported above dams on the Roanoke River, North Carolina and Virginia

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, Joseph E.

    2011-01-01

    American shad Alosa sapidissima are in decline throughout much of their native range as a result of overfishing, pollution, and habitat alteration in coastal rivers where they spawn. One approach to restoration in regulated rivers is to provide access to historical spawning habitat above dams through a trap-and-transport program. We examined the initial survival, movement patterns, spawning, and downstream passage of sonic-tagged adult American shad transported to reservoir and riverine habitats upstream of hydroelectric dams on the Roanoke River, North Carolina and Virginia, during 2007–2009. Average survival to release in 2007–2008 was 85%, but survival decreased with increasing water temperature. Some tagged fish released in reservoirs migrated upstream to rivers; however, most meandered back and forth within the reservoir. A higher percentage of fish migrated through a smaller (8,215-ha) than a larger (20,234-ha) reservoir, suggesting that the population-level effects of transport may depend on upper basin characteristics. Transported American shad spent little time in upper basin rivers but were there when temperatures were appropriate for spawning. No American shad eggs were collected during weekly plankton sampling in upper basin rivers. The estimated initial survival of sonic-tagged American shad after downstream passage through each dam was 71–100%; however, only 1% of the detected fish migrated downstream through all three dams and many were relocated just upstream of a dam late in the season. Although adult American shad were successfully transported to upstream habitats in the Roanoke River basin, under present conditions transported individuals may have reduced effective fecundity and postspawning survival compared with nontransported fish that spawn in the lower Roanoke River.

  12. Movement Patterns of American Shad Transported Upstream of Dams on The Roanoke River, North Carolina and Virginia

    USGS Publications Warehouse

    Harris, Julianne E.; Hightower, J.E.

    2011-01-01

    American shad Alosa sapidissima are in decline throughout much of their native range as a result of overfishing, pollution, and habitat alteration in coastal rivers where they spawn. One approach to restoration in regulated rivers is to provide access to historical spawning habitat above dams through a trap-and-transport program. We examined the initial survival, movement patterns, spawning, and downstream passage of sonic-tagged adult American shad transported to reservoir and riverine habitats upstream of hydroelectric dams on the Roanoke River, North Carolina and Virginia, during 2007–2009. Average survival to release in 2007–2008 was 85%, but survival decreased with increasing water temperature. Some tagged fish released in reservoirs migrated upstream to rivers; however, most meandered back and forth within the reservoir. A higher percentage of fish migrated through a smaller (8,215-ha) than a larger (20,234-ha) reservoir, suggesting that the population-level effects of transport may depend on upper basin characteristics. Transported American shad spent little time in upper basin rivers but were there when temperatures were appropriate for spawning. No American shad eggs were collected during weekly plankton sampling in upper basin rivers. The estimated initial survival of sonic-tagged American shad after downstream passage through each dam was 71–100%; however, only 1% of the detected fish migrated downstream through all three dams and many were relocated just upstream of a dam late in the season. Although adult American shad were successfully transported to upstream habitats in the Roanoke River basin, under present conditions transported individuals may have reduced effective fecundity and postspawning survival compared with nontransported fish that spawn in the lower Roanoke River.

  13. Using a non-physical behavioural barrier to alter migration routing of juvenile Chinook salmon in the Sacramento–San Joaquin River Delta

    USGS Publications Warehouse

    Perry, R.W.; Romine, J.G.; Adams, N.S.; Blake, A.R.; Burau, J.R.; Johnston, S.V.; Liedtke, T.L.

    2012-01-01

    Anthropogenic alterations to river systems, such as irrigation and hydroelectric development, can negatively affect fish populations by reducing survival when fish are routed through potentially dangerous locations. Non-physical barriers using behavioural stimuli are one means of guiding fish away from such locations without obstructing water flow. In the Sacramento–San Joaquin River Delta, we evaluated a bio-acoustic fish fence (BAFF) composed of strobe lights, sound and a bubble curtain, which was intended to divert juvenile Chinook salmon (Oncorhynchus tshawytscha) away from Georgiana Slough, a low-survival migration route that branches off the Sacramento River. To quantify fish response to the BAFF, we estimated individual entrainment probabilities from two-dimensional movement paths of juvenile salmon implanted with acoustic transmitters. Overall, 7.7% of the fish were entrained into Georgiana Slough when the BAFF was on, and 22.3% were entrained when the BAFF was off, but a number of other factors influenced the performance of the BAFF. The effectiveness of the BAFF declined with increasing river discharge, likely because increased water velocities reduced the ability of fish to avoid being swept across the BAFF into Georgiana Slough. The BAFF reduced entrainment probability by up to 40 percentage points near the critical streakline, which defined the streamwise division of flow vectors entering each channel. However, the effect of the BAFF declined moving in either direction away from the critical streakline. Our study shows how fish behaviour and the environment interacted to influence the performance of a non-physical behavioural barrier in an applied setting.

  14. Channel change on the Santa Cruz River, Pima County, Arizona, 1936-86

    USGS Publications Warehouse

    Parker, J.T.

    1993-01-01

    The Santa Cruz River, an ephemeral river that drains 8,581 square miles in southeastern Arizona, has a long history of channel instability. Since the late 19th century, lateral channel erosion has caused extensive property damage, particularly in Pima County. During the flood of 1983, about $100 million damage was caused in the Tucson area alone; most damage resulted from bank erosion on the Santa Cruz River and its tributaries. The nature, magni- tude, location, and frequency of channel change on the Santa Cruz River were highly variable in time and space from 1936 through 1986 along a 70-mile reach in Pima County, Arizona. Four mechanisms of lateral channel change--channel migration, avulsion and meander cutoff, channel widening, and arroyo widening--were identified on the Santa Cruz River. The dominant mechanism in a reach depends on channel morphology and flood magnitude. The dominant vertical change has been degradation. The timing and magnitude of channel change at a particular location are controlled primarily by hydroclimatic factors such as magnitude, duration, intensity, and frequency of precipitation and floods. The location of channel change and its magnitude in response to a given discharge are controlled largely by topographic, geologic, hydraulic, and artificial factors. Although much of the present morphology of the Santa Cruz River is the result of recent large floods, a direct link between hydroclimatic con- ditions and channel change is not always evident because resistance of the channel to erosion varies with time. (USGS)

  15. Fluvial Landforms and Landscape Transformations on a Large River Floodplain: Willamette River, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Wallick, R.

    2015-12-01

    Recent detailed mapping of the Willamette River floodplain in northwestern Oregon reveals insights into the floodplain landforms, their formative processes, and historical landscape transformations. Hierarchical mapping classification based mainly upon lidar topography, supplemented by aerial photographs, historical channel and soil maps, and targeted coring of floodplain soils, was carried out for 200 km of the mainstem Willamette River floodplain above Willamette Falls where floodplain landforms mainly reflect fluvial and anthropogenic influences. Stark differences in the character and distribution of floodplain landforms and their underlying stratigraphy give rise to three distinct process regimes along the fluvial portion of the Willamette River. Floodplain surfaces along 60 km of the Upper Willamette River floodplain generally rise 1-2 m above the low-flow water surface and are bisected by complex assemblage of overflow channels and large-amplitude abandoned bends formed by avulsions along this historically multi-thread anastomosing reach. Downstream, the 90 km-long Middle Willamette River between Corvallis and Newburg Pool becomes increasingly entrenched within its floodplain, with floodplains gradually rising up to 8 m above the low flow water surface. These floodplain surfaces are dominated by ridge and swale topography with occasional floodbasins reflecting gradual meander migration and floodplain aggradation. The 50 km-long Newberg Pool is entrenched and confined by Pleistocene Missoula flood deposits and bedrock valley walls. This low-gradient reach extends to the lip of the15-m high Willamette Falls. Historical declines in flood magnitude, bed-material supply, large wood, and bank erodibility result in a more stable modern-day floodplain with narrower active-channel corridor flanked by relict landforms formed by historical flow and sediment regime. Landscape transformations vary across the three process regimes but are greatest along Upper Willamette

  16. Partial transpose of random quantum states: Exact formulas and meanders

    SciTech Connect

    Fukuda, Motohisa; Sniady, Piotr

    2013-04-15

    We investigate the asymptotic behavior of the empirical eigenvalues distribution of the partial transpose of a random quantum state. The limiting distribution was previously investigated via Wishart random matrices indirectly (by approximating the matrix of trace 1 by the Wishart matrix of random trace) and shown to be the semicircular distribution or the free difference of two free Poisson distributions, depending on how dimensions of the concerned spaces grow. Our use of Wishart matrices gives exact combinatorial formulas for the moments of the partial transpose of the random state. We find three natural asymptotic regimes in terms of geodesics on the permutation groups. Two of them correspond to the above two cases; the third one turns out to be a new matrix model for the meander polynomials. Moreover, we prove the convergence to the semicircular distribution together with its extreme eigenvalues under weaker assumptions, and show large deviation bound for the latter.

  17. Tsunami intrusion in wide meandering channels: a Lagrangian numerical experiment

    NASA Astrophysics Data System (ADS)

    Couston, L. A.; Alam, M. R.

    2015-12-01

    Among the many difficulties of tsunami forecast, wave runup on sloped beaches remains a major obstacle in numerical simulations. Traditional Eulerian models must adjust the fluid flow domain continuously due to the moving shorelines, which can significantly affect the computational cost and results accuracy. An efficient though uncommon alternative for accurate runup predictions still exists, consisting in using a Lagrangian model as recently shown by e.g. Couston et al. (2015) who studied the runup of landslide tsunamis in lakes with a non-dispersive Lagrangian model. Here we introduce a fully-nonlinear Boussinesq-type model derived in the Lagrangian framework to investigate various cases of long-wave runup on curved beaches and meandering channels. The governing equations are expressed in terms of curvilinear Lagrangian coordinates, making the model suitable for accurate runup computations at shorelines of arbitrary geometry while retaining the inherent simplicity of a physical model discretized on a fixed and structured grid. We implement an elliptic grid generation algorithm to map the physical space to the computational space, and a high-order finite-difference scheme for time integration. The numerical model has a linear complexity in the number of unknowns when neglecting dispersive effects. We show that the formation of edge waves due to the sloped banks of a wide channel has a significant influence on the capability of a meander or constriction in reflecting the intruding tsunami, and we investigate the effect of dispersion. Reference: Couston, L.-A., Mei, C. C., & Alam, M.-R. (2015). Landslide tsunamis in lakes. Journal of Fluid Mechanics, 772, 784-804.

  18. Experimental Studies of bed topography and flow patterns in large-amplitude meanders: 2. Mechanisms

    NASA Astrophysics Data System (ADS)

    Whiting, Peter J.; Dietrich, William E.

    1993-11-01

    Large-amplitude river meanders develop multiple scour holes within a single bend that are observed to be part of overlapping shingle bars (Whiting and Dietrich, this issue). These bars, having wavelengths near 4 channel widths, consist of a pool along the outer concave bank and a depositional lobe along the inner convex bank. The development of multiple pools and lobes within a bend has been shown to cause localized bank erosion and channel trace distortion expressed as planform asymmetry and compound heads. In this second paper we describe experiments designed specifically to test hypotheses that propose multiple pools to be the result of an overshoot phenomenon, to be a consequence of an alternate bar-like instability, or to develop from a flow/planform instability. Although our experiments favor the hypothesis that multiple bars in bends of large amplitude arise from an alternate bar-like instability, experiments conducted over an immobile flat bed also reveal longitudinal oscillations in flow that may arise in these long bends. This secondary effect interacts with shingle bars to amplify pool expression at particular points along the channel.

  19. Conservation physiology in practice: how physiological knowledge has improved our ability to sustainably manage Pacific salmon during up-river migration

    PubMed Central

    Cooke, Steven J.; Hinch, Scott G.; Donaldson, Michael R.; Clark, Timothy D.; Eliason, Erika J.; Crossin, Glenn T.; Raby, Graham D.; Jeffries, Ken M.; Lapointe, Mike; Miller, Kristi; Patterson, David A.; Farrell, Anthony P.

    2012-01-01

    Despite growing interest in conservation physiology, practical examples of how physiology has helped to understand or to solve conservation problems remain scarce. Over the past decade, an interdisciplinary research team has used a conservation physiology approach to address topical conservation concerns for Pacific salmon. Here, we review how novel applications of tools such as physiological telemetry, functional genomics and laboratory experiments on cardiorespiratory physiology have shed light on the effect of fisheries capture and release, disease and individual condition, and stock-specific consequences of warming river temperatures, respectively, and discuss how these findings have or have not benefited Pacific salmon management. Overall, physiological tools have provided remarkable insights into the effects of fisheries capture and have helped to enhance techniques for facilitating recovery from fisheries capture. Stock-specific cardiorespiratory thresholds for thermal tolerances have been identified for sockeye salmon and can be used by managers to better predict migration success, representing a rare example that links a physiological scope to fitness in the wild population. Functional genomics approaches have identified physiological signatures predictive of individual migration mortality. Although fisheries managers are primarily concerned with population-level processes, understanding the causes of en route mortality provides a mechanistic explanation and can be used to refine management models. We discuss the challenges that we have overcome, as well as those that we continue to face, in making conservation physiology relevant to managers of Pacific salmon. PMID:22566681

  20. Insights on the opening of the Galerian mammal migration pathway from magnetostratigraphy of the Pleistocene marine-continental transition in the Arda River section (northern Italy)

    NASA Astrophysics Data System (ADS)

    Monesi, Edoardo; Muttoni, Giovanni; Scardia, Giancarlo; Felletti, Fabrizio; Bona, Fabio; Sala, Benedetto; Tremolada, Fabrizio; Francou, Carlo; Raineri, Gianluca

    2016-09-01

    We investigated the magnetostratigraphy of the Arda River section (northern Italy) where the transition from marine to continental sedimentation occurring in the Po River basin during the Pleistocene is registered. Four magnetic polarity reversals were used to construct an age model of sedimentation aided by marine biostratigraphy and tied to a standard δ18O curve from the literature. The section spans from the Olduvai subchron (1.94-1.78 Ma) across the Jaramillo subchron (1.07-0.99 Ma) up to the Brunhes-Matuyama boundary (0.78 Ma). The onset of continental deposition occurred during marine isotope stage (MIS) 30 at ˜1.04 Ma. An association of Villafranchian and Early Galerian mammals, including Sus strozzii and Ursus dolinensis, has been found in the continental sediments dated to MIS 29-27 (˜0.99 Ma). Above follows a prominent fluvial conglomerate attributed to the first major lowstand of the Pleistocene culminating with MIS 22 at ˜0.9 Ma during the late Early Pleistocene climate turnover (EPT). These and other data from the literature are used to reconstruct the onset of continental deposition in the greater Po basin and shed light on the opening of the migration pathway that brought far-traveled Galerian mammal immigrants to enter Europe for the first time during the EPT.

  1. Microbial water quality during the northern migration of Sandhill Cranes (Grus canadensis) at the central Platte River, Nebraska

    USGS Publications Warehouse

    Moser, Matthew T.

    2014-01-01

    The central Platte River is an important resource in Nebraska. Its water flows among multiple channels and supports numerous beneficial uses such as drinking water, irrigation for agriculture, groundwater recharge, and recreational activities. The central Platte River valley is an important stopover for migratory waterfowl and cranes, such as the Whooping (Grus americana) and Sandhill Cranes (Grus canadensis), in their annual northward traversal of the Central Flyway. Waterfowl, cranes, and other migratory birds moving across international and intercontinental borders may provide long-range transportation for any microbial pathogen they harbor, particularly through the spread of feces. Samples were collected weekly in the study reach from three sites (upstream, middle, and downstream from the roosting locations) during the spring of 2009 and 2010. The samples were analyzed for avian influenza, Escherichia coli, Cryptosporidium, Giardia, Campylobacter, and Legionella. Analysis indicates that several types of fecal indicator bacteria and a range of viral, protozoan, and bacterial pathogens were present in Sandhill Crane excreta. These bacteria and pathogens were present at a significantly higher frequency and densities in water and sediments when the Sandhill Cranes were present, particularly during evening roosts within the Platte River environment.

  2. Meandering of overgrown v-shaped defects in epitaxial GaN layers

    NASA Astrophysics Data System (ADS)

    Weidlich, P. H.; Schnedler, M.; Portz, V.; Eisele, H.; Dunin-Borkowski, R. E.; Ebert, Ph.

    2014-07-01

    The meandering of v-shaped defects in GaN(0001) epitaxial layers is investigated by cross-sectional scanning tunneling microscopy. The spatial position of v-shaped defects is mapped on ( 10 1 ¯ 0 ) cleavage planes using a dopant modulation, which traces the overgrown growth front. Strong lateral displacements of the apex of the v-shaped defects are observed. The lateral displacements are suggested to be induced by the meandering of threading dislocations present in the v-shaped defects. The meandering of the dislocation is attributed to interactions with inhomogeneous strain fields.

  3. On the characteristics of the wake meandering of a marine hydrokinetic turbine

    NASA Astrophysics Data System (ADS)

    Kang, S.

    2013-12-01

    Recently Kang et al. (Journal of Fluid Mechanics, submitted) showed that the hub vortex breakdown occurring downstream of a hydrokinetic turbine plays an important role in enhancing wake meandering. In this study the hub vortex breakdown and wake meandering phenomena are further examined using large-eddy simulation (Kang et al., Advances in Water Resources, 2012). Specifically, the effect of the incoming turbulence, the presence of hub and nacelle geometries, and the tip speed ratio of the rotor on the wake meandering and the hub vortex breakdown are examined.

  4. Spring migration ecology of the mid-continent sandhill crane population with an emphasis on use of the Central Platte River Valley, Nebraska

    USGS Publications Warehouse

    Krapu, Gary L.; Brandt, David A.; Kinzel, Paul J.; Pearse, Aaron T.

    2014-01-01

    We conducted a 10-year study (1998–2007) of the Mid-Continent Population (MCP) of sandhill cranes (Grus canadensis) to identify spring-migration corridors, locations of major stopovers, and migration chronology by crane breeding affiliation (western Alaska–Siberia [WA–S], northern Canada–Nunavut [NC–N], west-central Canada–Alaska [WC–A], and east-central Canada–Minnesota [EC–M]). In the Central Platte River Valley (CPRV) of Nebraska, we evaluated factors influencing staging chronology, food habits, fat storage, and habitat use of sandhill cranes. We compared our findings to results from the Platte River Ecology Study conducted during 1978–1980. We determined spring migration corridors used by the breeding affiliations (designated subpopulations for management purposes) by monitoring 169 cranes marked with platform transmitter terminals (PTTs). We also marked and monitored 456 cranes in the CPRV with very high frequency (VHF) transmitters to evaluate length and pattern of stay, habitat use, and movements. An estimated 42% and 58% of cranes staging in the CPRV were greater sandhill cranes (G. c. tabida) and lesser sandhill cranes (G. c. canadensis), and they stayed for an average of 20 and 25 days (2000–2007), respectively. Cranes from the WA–S, NC–N, WC–A, and EC–M affiliations spent an average of 72, 77, 52, and 53 days, respectively, in spring migration of which 28, 23, 24, and 18 days occurred in the CPRV. The majority of the WA–S subpopulation settled in the CPRV apparently because of inadequate habitat to support more birds upstream, although WA–S cranes accounted for >90% of birds staging in the North Platte River Valley. Crane staging duration in the CPRV was negatively correlated with arrival dates; 92% of cranes stayed >7 days. A program of annual mechanical removal of mature stands of woody growth and seedlings that began in the early 1980s primarily in the main channel of the Platte River has allowed distribution of crane

  5. Controls on the Alluviation of Oxbow Lakes by Bed Load as Observed Along the Sacramento River of California

    NASA Astrophysics Data System (ADS)

    Constantine, J. A.; Dunne, T.; Piegay, H.; Kondolf, G. M.

    2007-12-01

    As the products of meander cutoff that are widespread within many floodplains, oxbow lakes can affect the ability of rivers to migrate across their valleys, as well as physical and chemical exchanges between the river and floodplain environment. The particular functions of the oxbow lake are determined by the manner it is filled by sedimentation. Although the alluviation of oxbow lakes has been observed in natural settings and generalized by means of rules in planform evolution models, no theory exists to explain how oxbow lakes are filled because the controls on the process have not been widely studied or physically interpreted. Utilizing existing theory and field data from lakes of the Sacramento River, we examined the controls on oxbow alluviation by bed load and found that the transport of bed material through a channel abandoned by cutoff is highly sensitive to the orientation of the abandoned-channel entrance. In particular, the diversion angle, the angle between the approaching active- channel flow and the abandoned-channel entrance, is a direct control on discharge through the abandoned channel, and thus can significantly reduce boundary shear-stress and limit the transport capacity of bed load. The higher the angle, the more greatly reduced is the capacity to transmit bed material, and the more quickly the channel is hydraulically disconnected as diverted bed load rapidly aggrades the channel entrance. In contrast, the lower the angle, the longer the duration the channel remains hydraulically connected, and the more likely it will experience filling and narrowing by bed load because sufficient flow allows for the downstream and transverse transport of bed material. Our findings from the Sacramento River compare well to observations from other large meandering rivers and may explain why some lakes are terrestrialized within decades of cutoff, whereas others remain as open-water habitat for considerably longer.

  6. Survival Estimates for the Passage of Spring-Migrating Juvenile Salmonids through Snake and Columbia River Dams and Reservoirs, 2004-2005 Annual Report.

    SciTech Connect

    Smith, Steven G.; Muir, William D.; Marsh, Douglas M.

    2005-10-01

    In 2004, the National Marine Fisheries Service and the University of Washington completed the twelfth year of a study to estimate survival and travel time of juvenile salmonids (Oncorhynchus spp.) passing through dams and reservoirs on the Snake and Columbia Rivers. All estimates were derived from detections of fish tagged with passive integrated transponder tags (PIT tags). We PIT tagged and released a total of 19,621 hatchery steelhead, 8,128 wild steelhead, and 9,227 wild yearling Chinook salmon at Lower Granite Dam. In addition, we utilized fish PIT tagged by other agencies at traps and hatcheries upstream from the hydropower system and sites within the hydropower system. PIT-tagged smolts were detected at interrogation facilities at Lower Granite, Little Goose, Lower Monumental, McNary, John Day, and Bonneville Dams and in the PIT-tag detector trawl operated in the Columbia River estuary. Survival estimates were calculated using a statistical model for tag-recapture data from single release groups (the single-release model). Primary research objectives in 2004 were to (1) estimate reach survival and travel time in the Snake and Columbia Rivers throughout the migration period of yearling Chinook salmon O. tshawytscha and steelhead O. mykiss; (2) evaluate relationships between survival estimates and migration conditions; and (3) evaluate the survival-estimation models under prevailing conditions. This report provides reach survival and travel time estimates for 2004 for PIT-tagged yearling Chinook salmon (hatchery and wild), hatchery sockeye salmon O. nerka, hatchery coho salmon O. kisutch, and steelhead (hatchery and wild) in the Snake and Columbia Rivers. Results are reported primarily in the form of tables and figures; details on methodology and statistical models used are provided in previous reports cited here. Survival and detection probabilities were estimated precisely for most of the 2004 yearling Chinook salmon and steelhead migrations. Hatchery and

  7. Wild, scenic, and transcendental rivers

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    “A more lovely stream than this has never flowed on Earth,” 19th century American author Nathaniel Hawthorne wrote about the confluence of the Assabet and Concord Rivers, streams that meander about 40 km west of Boston, Massachusetts.Segments of these streams as well as the Assabet River became the newest additions to the U.S. National Wild and Scenic Rivers System, when President Bill Clinton signed into law the “Sudbury, Assabet, and Concord Wild and Scenic River Act” on April 9.

  8. Monitoring and Evaluation of Smolt Migration in the Columbia Basin : Volume XVI : Survival and Transportation Effects for Migrating Snake River Hatchery Chinook Salmon and Steelhead: Historical Estimates from 1996-2003.

    SciTech Connect

    Buchanan, Rebecca A.; Skalski, John R.

    2007-12-07

    In 2005, the University of Washington developed a new statistical model to analyze the combined juvenile and adult detection histories of PIT-tagged salmon migrating through the Federal Columbia River Power System (FCRPS). This model, implemented by software Program ROSTER (River-Ocean Survival and Transportation Effects Routine), has been used to estimate survival and transportation effects on large temporal and spatial scales for PIT-tagged hatchery spring and summer Chinook salmon and steelhead released in the Snake River Basin from 1996 to 2003. Those results are reported here. Annual estimates of the smolt-to-adult return ratio (SAR), juvenile inriver survival from Lower Granite to Bonneville, the ocean return probability from Bonneville to Bonneville, and adult upriver survival from Bonneville to Lower Granite are reported. Annual estimates of transport-inriver (T/I) ratios and differential post-Bonneville mortality (D) are reported on both a systemwide basis, incorporating all transport dams analyzed, and a dam-specific basis. Transportation effects are estimated only for dams where at least 5,000 tagged smolts were transported from a given upstream release group. Because few tagged hatchery steelhead were transported in these years, no transportation effects are estimated for steelhead. Performance measures include age-1-ocean adult returns for steelhead, but not for Chinook salmon. Annual estimates of SAR from Lower Granite back to Lower Granite averaged 0.71% with a standard error (SE) of 0.18% for spring Chinook salmon from the Snake River Basin for tagged groups released from 1996 through 2003, omitting age-1-ocean (jack) returns. For summer Chinook salmon from the Snake River Basin, the estimates of annual SAR averaged 1.15% (SE=0.31%). Only for the release years 1999 and 2000 did the Chinook SAR approach the target value of 2%, identified by the NPCC as the minimum SAR necessary for recovery. Annual estimates of SAR for hatchery steelhead from the

  9. Impact of channel incision on the hydraulics of flood flows: Examples from Polish Carpathian rivers

    NASA Astrophysics Data System (ADS)

    Wyżga, Bartłomiej; Zawiejska, Joanna; Radecki-Pawlik, Artur

    2016-11-01

    Channel deepening may result from channel incision or river metamorphosis changing a wide and shallow channel to a narrow and deep one. As only the first type of channel change leads to increased flow capacity of the channel, a lowering of water stage associated with a given discharge rather than a lowering of river bed should be used to identify channel incision. A lowering of minimum annual stage at gauging stations is typically used to assess the relative importance of channel incision along a river or within a particular region. Rivers of the Polish Carpathians incised by 0.5-3.8 m over the twentieth century, with the amount of incision being greater in their lower and middle courses than in the upper ones. Variability in the hydraulic importance of channel incision with increasing river size is analysed by comparing changes in the frequency of valley floor inundation at gauging stations located along the seventh-order Dunajec River. Despite a lower absolute amount of channel incision in the upper river course, here incision has increased channel conveyance and reduced the frequency of valley floor inundation considerably more than in the lower course. Hydraulic effects of channel incision depend also on lateral stability of an incising river. Low-energy rivers from the eastern part of the Polish Carpathians remained laterally stable during channel incision. This has resulted in substantial lowering of stages for low flood discharges and markedly smaller one for high-magnitude floods, whereas velocity of the flows conveyed over the highly elevated floodplains has decreased considerably. In high-energy rivers from the western part of the Polish Carpathians, alternation of incision and lateral channel migration has led to the formation of incised meander belts, with substantially lowered stages for all flood discharges and increased velocity of the flows conveyed over the newly-formed, low-lying floodplains.

  10. Insights into geomorphic and vegetation spatial patterns within dynamic river floodplains using soft classification approaches

    NASA Astrophysics Data System (ADS)

    Guneralp, I.; Filippi, A. M.; Guneralp, B.; You, M.

    2014-12-01

    Lowland rivers in broad alluvial floodplains create one of the most dynamic landscapes, governed by multiple, and commonly nonlinear, interactions among geomorphic, hydrologic, and ecologic processes. Fluvial landforms and land-cover patches composing the floodplains of lowland rivers vary in their shapes and sizes because of variations in vegetation biomass, topography, and soil composition (e.g., of abandoned meanders versus accreting bars) across space. Such floodplain heterogeneity, in turn, influences future river-channel evolution by creating variability in channel-migration rates. In this study, using Landsat 5 Thematic Mapper data and alternative image-classification approaches, we investigate geomorphic and vegetation spatial patterns in a dynamic large tropical river. Specifically, we examine the spatial relations between river-channel planform and fluvial-landform and land-cover patterns across the floodplain. We classify the images using both hard and soft classification algorithms. We characterize the structure of geomorphic landform and vegetation components of the floodplain by computing a range of class-level landscape metrics based on the classified images. Results indicate that comparable classification accuracies are accrued for the inherently hard and (hardened) soft classification images, ranging from 89.8% to 91.8% overall accuracy. However, soft classification images provide unique information regarding spatially-varying similarities and differences in water-column properties of oxbow lakes and the main river channel. Proximity analyses, where buffer zones along the river with distances corresponding to 5, 10, and 20 river-channel widths are constructed, reveal that the average size of forest patches first increase away from the river banks but they become sparse after a distance of 10 channel widths away from the river.

  11. Monitoring and Evaluation of Smolt Migration in the Columbia Basin : Volume XVIII: Survival and Transportation Effects of Migrating Snake River Wild Chinook Salmon and Steelhead: Historical Estimates From 1996-2004 and Comparison to Hatchery Results. Draft.

    SciTech Connect

    Buchanan, Rebecca A.; Skalski, John R.; Broms, Kristin

    2008-12-03

    The combined juvenile and adult detection histories of PIT-tagged wild salmonids migrating through the Federal Columbia River Power System (FCRPS) were analyzed using the ROSTER (River-Ocean Survival and Transportation Effects Routine) statistical release-recapture model. This model, implemented by software Program ROSTER, was used to estimate survival on large temporal and spatial scales for PIT-tagged wild spring and summer Chinook salmon and steelhead released in the Snake River Basin upstream of Lower Granite Dam from 1996 to 2004. In addition, annual results from wild salmonids were compared with results from hatchery salmonids, which were presented in a previous report in this series (Buchanan, R. A., Skalski, J. R., Lady, J. L., Westhagen, P., Griswold, J., and Smith, S. 2007, 'Survival and Transportation Effects for Migrating Snake River Hatchery Chinook Salmon and Steelhead: Historical Estimates from 1996-2003', Technical report, Bonneville Power Administration, Project 1991-051-00). These results are reported here. Annual estimates of the smolt-to-adult return ratio (SAR), juvenile inriver survival from Lower Granite to Bonneville, the ocean return probability from Bonneville to Bonneville, and adult upriver survival from Bonneville to Lower Granite are reported. Annual estimates of transport-inriver (T/I) ratios and differential post-Bonneville mortality (D) are reported on a dam-specific basis for release years with sufficient numbers of wild PIT-tagged smolts transported. Transportation effects are estimated only for dams where at least 1,000 tagged wild smolts were transported from a given upstream release group. Because few wild Chinook salmon and steelhead tagged upstream of Lower Granite Dam were transported before the 2003 release year, T/I and D were estimated only for the 2003 and 2004 release years. Performance measures include age-1-ocean adult returns for steelhead, but not for Chinook salmon. Spring and summer Chinook salmon release groups

  12. Channel Evolution on the Lower Elwha River, Washington, 1939-2006

    USGS Publications Warehouse

    Draut, Amy E.; Logan, Joshua B.; McCoy, Randall E.; McHenry, Michael; Warrick, Jonathan A.

    2008-01-01

    Analyses of historical aerial photographs of the lower Elwha River, Clallam County, Washington, reveal rates and patterns of channel change in this dammed, anabranching river between 1939 and 2006. Absolute positional changes of the active-floodplain margins, which commonly exceeded 50 m over that interval, have exceeded 400 m locally. Annualized rates of channel movement were typically ~2 to 10 m/yr; higher annualized rates over some time intervals are attributable to the formation of new channels by episodic avulsion. Channel movement by more gradual lateral meander migration was also common. Anthropogenic modification of the floodplain between the 1940s and 1980s substantially altered channel form and position. This analysis of rates and patterns of channel change over nearly 70 years on the lower Elwha River is intended to characterize the evolution of the river throughout most of the time interval when two large dams have been in place upstream. Channel morphology and rates of channel movement are expected to change significantly in response to removal of the dams and re-establishment of the upstream sediment supply during a major river-restoration project.

  13. Changing river courses in the western part of the Ganga-Brahmaputra delta

    NASA Astrophysics Data System (ADS)

    Rudra, Kalyan

    2014-12-01

    The Ganga-Brahmaputra delta is the largest on Earth, the product of two of the world's largest and siltiest rivers. It is formed in a basin located over the zone where the Indian plate subducts beneath the Himalaya to the north and the Indo-Burman ranges to the east. The distributaries in the south-western part of the delta remain disconnected from the Ganga-Padma during the lean season, although they are still active in bank erosion and sediment transport during the monsoon. Four distributaries of the Bhagirathi-Hugli (the westernmost branch of the Ganga) have gone dry during known historical period. In many cases, the natural decay of rivers has been exacerbated by the human intervention, especially where rivers are embanked and no allowance made for their migration through meandering and avulsion. In the coastal zone where mangroves were cleared and creeks were embanked since the late 18th century, decay of channels, and advancement of the sea towards inland have been aggravated. The subsequent attempt of flushing the sediment load to the sea from the estuary to improve the status of navigation in the Bhagirathi-Hugli River was not successful to the level of expectation. This paper deals with the decay and changing courses of rivers in the western part of the Ganga-Brahmaputra delta.

  14. Survival and Migration Behavior of Juvenile Coho Salmon in the Klamath River Relative to Discharge at Iron Gate Dam, Northern California, 2007

    USGS Publications Warehouse

    Beeman, John W.; Juhnke, Steve; Stutzer, Greg; Hetrick, Nicholas

    2008-01-01

    This report describes a study of survival and migration behavior of radio-tagged juvenile coho salmon (Oncorhynchus kisutch) in the Klamath River, northern California, in 2007. This was the third year of a multi-year study with the goal of determining the effects of discharge at Iron Gate Dam (IGD) on survival of juvenile coho salmon downstream. Survival and factors affecting survival were estimated in 2006 and 2007 after work in 2005 showed radio telemetry could be used effectively. The study has included collaborative efforts among U.S. Geological Survey (USGS), U.S. Fish and Wildlife Service (USFWS), the Karuk and Yurok Tribal Fisheries Departments, and the U.S. Bureau of Reclamation. The objectives of the study included: (1) estimating the survival of wild and hatchery juvenile coho salmon in the Klamath River downstream of Iron Gate Dam, determining the effects of discharge and other covariates on juvenile coho salmon survival (2) and migration (3), and (4) determining if fish from Iron Gate Hatchery (IGH) could be used as surrogates for the limited source of wild fish. We have been able to meet the first objective by estimating the survivals of hatchery and wild fish (when available) downstream of IGD. We have not yet met the second or third objectives, because we have been unable to separate effects of discharge from other environmental variables as they pertain to the survival or migration of juvenile coho salmon. This was foreseen when the study began, as it was known there would likely be no experimental discharges. A multi-year analysis will be conducted after the data for the third planned year are available. The fourth objective was initiated in 2006, but wild fish were not available in 2007. The next year wild fish may be available is in 2009, based on their 3-year cycle of abundance. River discharges during the 2007 study period (April 10 through July 28, 2007) were below average compared to the period of record beginning in 1962. Average daily

  15. Imaging beneath the skin of large tropical rivers: System morphodynamics of the Fly and Beni Rivers revealed by novel sub-surface sonar, deep coring, and modelling

    NASA Astrophysics Data System (ADS)

    Aalto, R. E.; Grenfell, M.; Lauer, J. W.

    2011-12-01

    channel negotiates "dog-leg" meanders and traverses a bed composed of a stacked sequence of fine layers; 3) An ancient channel network buried below the current bed of Lake Murray, indicating a ~10m rise in the Strickland River near that location; 4) The prevalence of clay in many of our deep cores throughout the Strickland, Fly, and Lake Murray floodplains; and 5) 14-C dating of deep cores which indicates that the entire Fly River system aggraded >10m rapidly during the mid Holocene. It appears that clay units dominate large portions of the channel bed. Furthermore, this clay often appears to control the morphodynamics of the channel -- as observed in the field and substantiated with modelling in Delft3D. We have recently completed a similar sonar/coring survey of 100s of km of the Beni River in Northern Bolivia. Particular attention was paid to the subsurface structure of meander bends, with an aim of understanding the controls on migration rates in this rapidly evolving system. Results are compared to GIS and modelling analyses of channel migration. We conclude with a synthesis of how cohesive clay-rich lithology can potentially play a major role in orchestrating the channel morphodynamics and Holocene evolution of a range of large tropical rivers.

  16. Channel-changing processes on the Santa Cruz River, Pima County, Arizona, 1936-86

    USGS Publications Warehouse

    Parker, John T.C.; ,

    1990-01-01

    Lateral channel change on the mainly ephemeral Santa Cruz River, Pima County, Arizona, causes damage and has spawned costly efforts to control bank erosion. Aerial photographs, historical data, and field observations are used to document the history of channel change since 1936. Variability in the nature and degree of channel change over time and space is shown. Three major channel change processes are: (1) migration by bank erosion during meander migration or initiation; (2) avulsion by overbank flooding and flood plain incision; (3) widening by erosion of low, cohesionless banks during floods and arroyo widening by undercutting and mass wasting of deeply incised vertical walls. The first process generally is a product of low to moderate flows or waning high flows; the others result mainly from higher flows, though sensitive arroyo walls may erode during relatively low flows. Channel morphology, bank resistance, and hydrology are factors determining the dominant channel-changing process on a particular reach of the river. Present river morphology reflects high flows since the 1960's.

  17. River channel changes of the Subansiri in Assam, India

    NASA Astrophysics Data System (ADS)

    Goswami, U.; Sarma, J. N.; Patgiri, A. D.

    1999-12-01

    The sequential changes in the position of banklines as a result of bank erosion, as well as various changes in the channel have been studied in the Subansiri river in Assam, India. The study was carried out from available topographic maps of 1920, 1970 and satellite imagery of 1990. The types of changes taking place in the Subansiri river channel as observed from the above-mentioned maps and imagery are grouped into four categories: (1) alteration of the direction of flow due to neck cut-off, (2) widening of a channel in response to bar development, (3) development (and subsequent abandonment) of anabranches, and (4) progressive shifting of meander bends. The river channel has become substantially wider during the period of 1970-1990. There has also been a progressive increase in the number and area of mid-channel bars with a corresponding decrease in the number and area of point bars during 1920-1990. These periodic and progressive changes are responsible for a change in channel pattern of the river. A study made on nature and amount of change in the banklines of the Subansiri river by dividing the channel (84 km in 1970) into 10 equal segments reveals that the types of change are varied, and in some cases chaotic in nature. Study of the bankline shift of the Subansiri determined separately for the periods 1920-1970, 1970-1990 and 1920-1990 at 20 evenly spaced transverse sections reveals that there has been a substantial westward shift of both the banklines, up to a maximum of 6 km, in the three upstream sections during 1920-1970. However, shifting of banklines in both directions and the unequal amount of shifting in the same direction have caused a marked increase in channel width during 1970-1990. It is found that due to bankline migration, the total amount of area eroded along the entire course under study during 1920-1970 and 1970-1990 are 107.90 and 57.50 km 2, respectively. The overall sinuosity which was 1.51 in 1920 has decreased to 1.30 in 1970, while the

  18. Monitoring and Evaluation of Smolt Migration in the Columbia River Basin : Volume VI : Evaluation of the 2000 Predictions of the Run-Timing of Wild Migrant Chinook Salmon and Steelhead Trout, and Hatchery Sockeye Salmon in the Snake River Basin, and Combined Wild Hatchery Salminids Migrating to Rock Island and McNary Dams using Program RealTime.

    SciTech Connect

    Burgess, Caitlin

    1998-07-01

    Program RealTime provided tracking and forecasting of the 2000 in season outmigration via the internet for stocks of wild PIT-tagged spring/summer chinook salmon. These stocks were ESUs from nineteen release sites above Lower Granite dam, including Bear Valley Creek, Big Creek, Camas Creek (new), Cape Horn Creek, Catherine Creek, Elk Creek, Herd Creek, Imnaha River, Johnson Creek (new), Lake Creek, Loon Creek, Lostine River, Marsh Creek, Minam River, East Fork Salmon River (new), South Fork Salmon River, Secesh River, Sulfur Creek and Valley Creek. Forecasts were also provided for two stocks of hatchery-reared PIT-tagged summer-run sockeye salmon, from Redfish Lake and Alturas Lake (new); for a subpopulation of the PIT-tagged wild Snake River fall subyearling chinook salmon; for all wild Snake River PIT-tagged spring/summer yearling chinook salmon (new) and steelhead trout (new)detected at Lower Granite Dam during the 2000 outmigration. The 2000 RealTime project began making forecasts for combined wild- and hatchery-reared runs-at-large of subyearling and yearling chinook, coho, and sockeye salmon, and steelhead trout migrating to Rock Island and McNary Dams on the mid-Columbia River and the mainstem Columbia River. Due to the new (in 1999-2000) Snake River basin hatchery protocol of releasing unmarked hatchery-reared fish, the RealTime forecasting project no longer makes run-timing forecasts for wild Snake River runs-at-large using FPC passage indices, as it has done for the previous three years (1997-1999). The season-wide measure of Program RealTime performance, the mean absolute difference (MAD) between in-season predictions and true (observed) passage percentiles, improved relative to previous years for nearly all stocks. The average season-wide MAD of all (nineteen) spring/summer yearling chinook salmon ESUs dropped from 5.7% in 1999 to 4.5% in 2000. The 2000 MAD for the hatchery-reared Redfish Lake sockeye salmon ESU was the lowest recorded, at 6.0%, down

  19. Identification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology

    USGS Publications Warehouse

    Tiffan, K.F.; Rondorf, D.W.; Garland, R.D.; Verhey, P.A.

    2000-01-01

    We tested the use of body morphology to distinguish among subyearling fall-run, subyearling spring-run, and yearling spring-run smolts of chinook salmon Oncorhynchus tshawytscha at two lower Snake River dams during the summer emigration. Based on principal-components analysis, subyearling fall-run chinook salmon had smaller heads and eyes, deeper bodies, and shorter caudal peduncles than yearling spring-run chinook salmon. Subyearling spring-run chinook salmon had characteristics of both subyearling fall-run and yearling spring-run chinook salmon. Subyearling fall-run and yearling spring-run chinook salmon were classified with more than 80% accuracy by means of discriminant analysis. Classification accuracy for subyearling spring-run chinook salmon was only 26%. We conclude that body morphology can be used to accurately identify the age of chinook salmon smolts but not the run. Therefore, genetic analyses are the only means of reliably determining the run composition of summer migrants in the lower Snake River.

  20. Effect of a meandering channel on wetland performance

    NASA Astrophysics Data System (ADS)

    Savickis, J.; Bottacin-Busolin, A.; Zaramella, M.; Sabokrouhiyeh, N.; Marion, A.

    2016-04-01

    Vegetation plays an important role in controlling mixing and contaminant removal in wetlands. Recent studies have shown that the hydraulic performance of a wetland can be significantly affected by the presence of a main flow channel (MFC) where vegetation density is much lower than the average vegetation density in the wetland. The existence of a main flow channel induces short-circuiting, which reduces hydraulic and treatment efficiency. A numerical study was carried out to analyze the effect of channel sinuosity and vegetation density on the hydraulic performance of a channelized wetland. A rectangular wetland characterized by a meandering channel and later vegetated zones (LVZs) was considered, and numerical simulations were carried out using a 2-D depth-average hydrodynamic and solute transport model. The hydraulic performance was analyzed as a function of the average vegetation density, channel sinuosity and the ratio of vegetation densities in the LVZs and the MFC. Results show that increasing sinuosity of the main flow channel can promote mixing and improve hydraulic efficiency. Different performance metrics also indicate negligible impact of the average vegetation density on the hydraulic performance, especially when the width of the MFC is relatively large.

  1. The Regional Salmon Outmigration Study--survival and migration routing of juvenile Chinook salmon in the Sacramento-San Joaquin River Delta during the winter of 2008-09

    USGS Publications Warehouse

    Romine, Jason G.; Perry, Russell W.; Brewer, Scott J.; Adams, Noah S.; Liedtke, Theresa L.; Blake, Aaron R.; Burau, Jon R.

    2013-01-01

    Juvenile Chinook salmon (Oncorhynchus tshawytscha) emigrating from natal tributaries of the Sacramento River may use a number of migration routes to navigate the Sacramento-San Joaquin River Delta (hereafter called “the Delta”), each of which may influence their probability of surviving. We applied a mark-recapture model to data from acoustically tagged juvenile late fall-run Chinook salmon that migrated through the Delta during the winter of 2008–09 to estimate route entrainment, survival, and migration times through the Delta. A tag-life study was conducted to determine the potential for premature tag failure. Tag failure began after 12 days and continued until the 45th day. Travel times of tagged fish exceeded minimum tag-failure times, indicating that survival estimates obtained from this study were negatively biased due to tag failure prior to fish exiting the Delta. Survival estimates were not adjusted and represent the joint probability of tag survival and fish survival. However, relative comparisons of survival among Chinook salmon choosing different routes appeared to be robust to tag failure, and migration-routing parameters were unaffected by tag failure. Migration-routing patterns were consistent among release groups. The Sacramento River was the primary migration route for all release groups except one. The percentage of fish entering the Sacramento River ranged from 33 to 55 percent. Sutter and Steamboat Sloughs were the secondary migration route for 9 of the 10 releases. The percentage of fish migrating through this route ranged from 10 to 35 percent. Entrainment into the interior Delta ranged from 15 to 33 percent. The Delta Cross Channel gates were open for 7 of the 10 releases. Entrainment into the interior Delta through the cross channel ranged from 1 to 27 percent. We estimated route-specific survival for 10 release groups that were released between November 14, 2008, and January 19, 2009. Population-level survival through the Delta

  2. Numerically Simulating the Hydrodynamic and Water Quality Environment for Migrating Salmon in the Lower Snake River, 2002-2003 Technical Report.

    SciTech Connect

    Cook, C.; Richmond, M.; Coleman, A.

    2003-06-01

    Summer temperatures in the Lower Snake River can be altered by releasing cold waters that originate from deep depths within Dworshak Reservoir. These cold releases are used to lower temperatures in the Clearwater and Lower Snake Rivers and to improve hydrodynamic and water quality conditions for migrating aquatic species. This project monitored the complex three-dimensional hydrodynamic and thermal conditions at the Clearwater and Snake River confluence and the processes that led to stratification of Lower Granite Reservoir (LGR) during the late spring, summer, and fall of 2002. Hydrodynamic, water quality, and meteorological conditions around the reservoir were monitored at frequent intervals, and this effort is continuing in 2003. Monitoring of the reservoir is a multi-year endeavor, and this report spans only the first year of data collection. In addition to monitoring the LGR environment, a three-dimensional hydrodynamic and water quality model has been applied. This model uses field data as boundary conditions and has been applied to the entire 2002 field season. Numerous data collection sites were within the model domain and serve as both calibration and validation locations for the numerical model. Errors between observed and simulated data varied in magnitude from location to location and from one time to another. Generally, errors were small and within expected ranges, although, as additional 2003 field data becomes available, model parameters may be improved to minimize differences between observed and simulated values. A two-dimensional, laterally-averaged hydrodynamic and water quality model was applied to the three reservoirs downstream of LGR (the pools behind Little Goose, Lower Monumental, and Ice Harbor Dams). A two-dimensional model is appropriate for these reservoirs because observed lateral thermal variations during summer and fall 2002 were almost negligible; however, vertical thermal variations were quite large (see USACE 2003). The numerical

  3. Influences of Relative Sea-Level Rise and Mississippi River Delta Plain Evolution on the Holocene Middle Amite River, Southeastern Louisiana

    USGS Publications Warehouse

    Autin, W.J.

    1993-01-01

    The Holocene geomorphic history of southeastern Louisiana's middle Amite River is recorded in the stratigraphy of three alloformations, identified in decreasing age as the Watson (WAT), Denham Springs (DS), and Magnolia Bridge (MAG). The WAT meander belt formed by at least 9000 yr B.P., when sea level was lower and the Amite River was tributary to a larger ancestral drainage basin. The DS became an active meander belt by at least 3000 yr B.P., in response to relative sea-level rise and eastward progradation of the Mississippi River delta plain. The MAG developed its meander belt, in part, during the European settlement of the drainage basin, and is now attempting to adjust to modern anthropogenic influences. Geomorphic influences on the middle Amite River floodplain have temporal and spatial components that induce regional- and local-scale effects. Regional extrinsic influences caused meander belt avulsion that produced alloformations. However, local influences produced intrinsic geomorphic thresholds that modified channel morphology within a meander belt but did not induce alloformation development. Base-level influences of the relative sea-level rise and the Mississippi River delta plain were so dominant that the effects of possible climate change were not recognized in the Holocene Amite River system.

  4. [Migration and transformation of nitrogen in urban stream located in plain river-net area based on water resources regulation].

    PubMed

    Liu, Bo; Sheng, Ming; Zhu, Qiang; Yang, Shuang; Tan, Bing-chao; Fan, Ran; Nan, Xu-jun; He, Mao- yang; Wang, Guo-xiang

    2014-09-01

    To study hydrological features and physical and chemical characteristics of urban stream located in the plain river network area in the process of water resources regulation, and to discuss the forming and composition of nitrogen in urban stream based on water resources regulation. Effects of water regulation on the ammonium release from sediments in urban stream were studied under the condition of experimental simulation. The results showed that diurnal variation of water depth under the action of water resources regulation was significant. The value of DO in the overlying water along the water resources regulation path tended to decrease, while the concentration of permanganate index tended to increase. The concentration of nitrate in overlying water along the water resources regulation path gradually decreased, while the concentration of ammonium significantly increased. DO and permanganate index were the main factors influencing the concentrations of nitrate and ammonium in overlying water. Ammonium released from the sediments was an important source of ammonium in overlying water. Water resources regulation had a significant influence (P < 0. 05) on the concentration of ammonium in overlying water, but had no significant influence on the amount of cumulative ammonium released from sediments (P > 0. 05).

  5. High interpopulation genetic differentiation and unidirectional linear migration patterns in Myricaria laxiflora (Tamaricaceae), an endemic riparian plant in the Three Gorges Valley of the Yangtze River.

    PubMed

    Liu, Yifei; Wang, Yong; Huang, Hongwen

    2006-02-01

    Myricaria laxiflora is restricted to the riverbanks of the Yangtze River valley and will be completely lost owing to the construction of the Three Gorges Dam. Genetic diversity and structure of nine natural and one ex situ populations were investigated using amplified fragment length polymorphisms (AFLPs). A moderate level of gene diversity was found in natural populations, while the ex situ population had the highest. The F statistics calculated by different approaches consistently revealed a high genetic differentiation among natural populations, contributing >45% of the total gene diversity. The Bayesian-based analysis differentiated nine independent populations in accordance with the sites sampled. Estimates of gene flow by F(ST) and coalescent-based simulation analysis indicated a restricted recurrent gene exchange among populations (Nm = 0.290-0.401), whereas genetic distance-based clustering and coalescent-based assignment analyses revealed significant genetic isolation among populations. The migration pattern in M. laxiflora is best explained by a classical metapopulation model, but with a unique unidirectional direction underlined by hydrochoric force that drove dispersal of seeds and propagules from upstream toward downstream populations. Previous efforts in preserving genomic integrity in ex situ conservation were evaluated, and the results provide valuable information to formulate conservation guidelines for successfully reintroducing M. laxiflora to the wild.

  6. Solar Energetic Particle transport along meandering interplanetary magnetic field lines

    NASA Astrophysics Data System (ADS)

    Laitinen, Timo; Kopp, Andreas; Effenberger, Frederic; Dalla, Silvia; Marsh, Mike

    2016-04-01

    Recent multi-spacecraft Solar Energetic Particle (SEP) observations have challenged the traditional view of SEP production and interplanetary transport. In several events, the SEP intensities rise fast even at 180 degree longitudinal distance from the flare location. For many events the anisotropy of the SEPs has been found to depend on the observer's longitude, being stronger at locations that are well magnetically connected to the assumed SEP source region, as compared to wider longitudinal reaches. This suggests that interplanetary transport is an important factor for the SEP cross-field extent. The traditional modelling approach, with diffusive cross-field propagation, however, requires diffusion across the mean magnetic field much faster than that supported by current theories. We study the temporal and spatial evolution of SEP intensities and anisotropy using a new SEP transport model, FP+FLRW, which incorporates field-line random walk (FLRW) into the Fokker-Planck (FP) transport modelling framework. The FP+FLRW model was introduced by Laitinen et al (2013), who found using full-orbit simulations that the cross-field propagation of particles early in an SEP event is not diffusive, but dominated by deterministic propagation along stochastically meandering turbulent field-lines. We have extended the FP+FLRW model to a Parker spiral geometry, and show that it is able to reproduce the observed fast access of SEPs to a wide range of longitudes. The observed Gaussian shaped distribution of peak intensities versus longitude, having a sigma=30-50 degrees, is reproduced already for a narrow source region, while using realistic interplanetary transport conditions. We compare the anisotropy evolution of an SEP event given by the FP+FLRW model to that given by the traditional FP approach, and discuss the implications of our findings for the SEP event origins, source width and the role of interplanetary turbulence in the interpretation of the SEP observations.

  7. Channel adjustments to historical disturbances along the lower Brazos and Sabine Rivers, south-central USA

    NASA Astrophysics Data System (ADS)

    Heitmuller, Franklin T.

    2014-01-01

    Historical channel adjustments are documented and discussed in context with anthropogenic disturbances along two meandering, coastal plain rivers - the lower Brazos and Sabine Rivers in the south-central United States. Hard-copy streamflow-measurement notes of the U.S. Geological Survey were utilized to render historical cross sections (1925-2007) at nine gauging stations, which were complemented with repeat photographs and flood-frequency analysis to assess trajectories of channel change and interpret causative mechanisms. Downstream- and upstream-propagating disturbances caused episodes of channel-bed incision and aggradation at different locations for distinct time periods along both rivers. Incision associated with upstream dams is detected, but channels are compensated downstream with sediment inputs from lateral channel migration and tributaries. In one case, temporary aggradation along the Brazos River at Waco was likely caused by a combination of dam construction and regional soil erosion. Channel-bed incision on the lowermost Brazos River is unrelated to dams, but is associated with instream aggregate extraction, possibly in conjunction with downstream channelization. On the Sabine River, extensive aggradation during the 1930s might be associated with logging activities (1880s-1930s), but whether the cause is pervasive regional-scale hillslope erosion or local-scale mill-site activities is indeterminate. Following passage of this sediment, the river generally recovered to pre-disturbance conditions and has exhibited stability despite a mainstem reservoir. Translation of this sediment slug is attenuated by a transition to a flood-prone, distributary-dominated system downstream of the Holocene-Pleistocene terrace onlap position. Additional findings include cross-channel hingepoints separating thalweg incision from simultaneous point-bar or bank accretion at meander bends, which indicates channel adjustment occurs along non-cohesive beds in preference to

  8. Temporal variation of meandering intensity and domain-wide lateral oscillations of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Lee, Tong; Cornillon, Peter

    1995-01-01

    The path of the Gulf Stream exhibits two modes of variability: wavelike spatial meanders associated with instability processes and large-sale lateral shifts of the path presumably due to atmospheric forcing. The objectives of this study are to examine the temporal variation of the intensity of spatial meandering in the stream, to characterize large-scale lateral oscillations in the stream's path, and to study the correlation betwen these two dynamically distinct modes of variability. The data used for this analysis are path displacemets ofthe Gulf Stream between 75 deg and 60 deg W obtained from AVHRR-derived (Advanced Very High Resolution Radiometer) infrared images for the period April 1982 through December 1989. Meandering intensity, measured by the spatial root-mean-sqaure displacement of the stream path, displays a 9-month dominant periodicity which is persistent through the study period. The 9-month fluctuation in meandering intensity may be related to the interaction of Rosseby waves with the stream. Interannual variation of meandering intensity is also found to be significant, with meandering being mich more intense during 1985 than it was in 1987. Annual variation, however,is weak and not well-defined.The spatially averaged position of the stream, which reflects nonmeandering large-scale lateral oscillations of the stream path, is dominated by an annual cycle. On average, the mean position is farthest north in November and farthest south in April. The first empirical orthogonal function mode of the space-time path displacements represents lateral oscillatins that are in-phase over the space-time domain. Interannual oscillations are also observed and are found to be weaker than the annual oscillation. The eigenvalue of the first mode indicates that about 21.5% of the total space-time variability of the stream path can be attibuted to domain-wide lateral oscillation. The correlation between meandering intensity and domain-wide lateral oscillations is very

  9. Geological controls on alluvial river behaviour: a comparative study of three rivers on the South African Highveld

    NASA Astrophysics Data System (ADS)

    Tooth, S.; Brandt, D.; Hancox, P. J.; McCarthy, T. S.

    2004-01-01

    Owing to tectonic readjustments following the breakup of Gondwana, many rivers in the subhumid to semi-arid South African Highveld are in a long-term state of incision, with their channel beds positioned on or just above bedrock. Comparison of the upper Klip River, the Schoonspruit and the Venterspruit, three adjacent left-bank tributaries of the Vaal River, demonstrates how dolerite sills and dykes form local base levels in the longitudinal profiles and thus exert strong, but variable, controls on river behaviour in the upstream, dominantly alluvial reaches. The upper Klip River flows largely over weakly cemented Karoo Supergroup sandstones but also crosses highly resistant dolerite dykes and sills. On the sandstones, vertical erosion rates are retarded by the slow erosion of the downstream dolerites, and in the interim the river is laterally planing bedrock and meandering extensively (sinuosity ( P) up to ˜1.75) within broad (up to 1.5 km wide) floodplains marked by oxbow lakes and abandoned channels. The floodplains host extensive wetlands that are in a near-pristine condition. The Schoonspruit flows largely over erodible Karoo Supergroup shales in its upper and middle reaches but also crosses a resistant dolerite sill in its lower reaches. On the shales, vertical erosion previously was retarded by the downstream dolerite, and the river laterally planed bedrock and carved a wide valley. The river formerly meandered ( P˜1.99) within a broad (up to 1 km wide) floodplain marked by oxbows but partial breaching of the dolerite has resulted in headward knickpoint migration, which in turn has led to incision into shale, abandonment and desiccation of the floodplain wetlands, and secondary erosion of the valley fills by dongas (gullies). The Venterspruit also flows largely over erodible Karoo Supergroup shales, apparently having completely breached a dolerite sill in its lower reaches. Vertical erosion has not been retarded to the same degree as on the Klip and the

  10. Quantifying the co-evolution of morphology, hydraulics and spawning habitat in a recently restored gravel-bed river

    NASA Astrophysics Data System (ADS)

    Harrison, L. R.; Legleiter, C. J.; Wydzga, A. M.; Dunne, T.

    2008-12-01

    An emergent paradigm within restoration science is that restoration of natural physical processes is the best way to restore habitat for native organisms in degraded rivers. This concept, which underpins many restoration projects, is based on the notion that the establishment of an actively migrating, alluvial river channel-floodplain system will provide a number of desired ecological functions, each related to specific physical processes that occur at the habitat-scale. Here we quantify the rates of morphologic change, channel migration and the development of high-quality habitat, using a recently restored gravel-bed reach of the Merced River, California, USA. DEM-derived differences in bed elevation indicate that sediment storage accelerated processes of bar-building, pool scour, and bank erosion, leading to more asymmetric cross- sectional geometry. The volume of sediment stored on developing point bars was correlated with the migration distance of the outer bank, whereas in bends that have not accumulated sediment there has been little erosion, suggesting that channel migration was influenced by sediment supply as well as by channel curvature. The documented channel changes have had marked results on flow hydraulics, leading to decreased velocities over riffles and increased velocities in pools during low flow spawning conditions. Habitat modeling indicates that the quality of Chinook salmon (Oncorhynchus tshawytscha) spawning habitat has improved following the initial channel construction. These changes in morphology, hydraulics and habitat availability occurred primarily during two sustained periods of overbank flow. Collectively, these results highlight the importance of overbank flows and a sediment supply sufficient for bar growth in meander migration and creating channel complexity and high-quality habitat.

  11. Holocene environment changes around the Sara Us River, northern China, revealed by optical dating of lacustrine-aeolian sediments

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Sheng, Yongwei; Li, Bo; Fan, Yuxin

    2016-04-01

    The Sara Us River is located along the boundary of the Mu Us Desert and the Chinese Loess Plateau in northern China. The river has cut down through Quaternary sediments creating 70-80 m deep valleys with thick lacustrine/aeolian sequences exposed. We applied optical stimulated luminescence on sediments from a Holocene section of aeolian sand/lacustrine deposits in the top of the river valley. The dating results show that a humid period existed from 7.1 to 2.0 ka ago as evidenced by two layers of peat and lacustrine sediments. However, compared to other published Holocene sections in the Sara Us River valleys close to the section under studying, the local environment experienced very complicated changes during the Holocene. All of the sections recorded a period with drought and/or cold before the Holocene at around 13 ka, and an episode of aridity after about 2 ka ago as evidenced by the layers of aeolian sand. However, the ages of the lacustrine and peat layers in these sections are substantially different. Geomorphological analysis by digital elevation models does not support the existence of a mega lake covering the study area at 2 ka. The intricate environmental changes may have been caused by the meandering of the Sara Us River. Environmental changes also strongly affected human migration in this area, which is documented by Chinese historical records.

  12. Late Quaternary incision rates in the southern French Alps from river longitudinal profiles inversion: climatic forcing and internal adjustments.

    NASA Astrophysics Data System (ADS)

    Petit, Carole; Cassol, Davide; Rolland, Yann; Saillard, Marianne

    2016-04-01

    Southern French Alps, and especially the external crystalline massifs, show evidences of rapid river incision featured by deeply incised gorges and widespread active landslides. The onset of rapid incision is not precisely dated, but cosmogenic nuclide dating of river polished profiles evidences rapid incision (of the order of 2-3 mm.yr-1) since 20 ka. These data suggest that it may be related to temperature and runoff increase due to glacier melting after le last glacial maximum (LGM). In this study, we use river longitudinal profiles from tributaries of the Tinée River, in the Argentera-Mercantour crystalline massif, to determine recent incision rate (IR) variations through time with the inversion method of Goren et al. (2014). Overall, the background IR is of approximately 5 mm.yr-1, in agreement with recent IR estimates from cosmogenic nuclide dating in the Tinée River. Incision rate histories of all tributaries show periodic pulses of large IR that could be correlated to quaternary interglacials and interstadials, based on the comparison with global temperature curves. However, some tributaries show very large IR in the Holocene period, whereas others show a recent (post 10 ka) IR decrease. We suggest that local internal adjustments, possibly in relation with meander migration of the main stem, are responsible for these different behaviors.

  13. Flood plain and channel dynamics of the Quinault and Queets Rivers, Washington, USA

    USGS Publications Warehouse

    O'Connor, J. E.; Jones, M.A.; Haluska, T.L.

    2003-01-01

    Observations from this study and previous studies on the Queets River show that channel and flood-plain dynamics and morphology are affected by interactions between flow, sediment, and standing and entrained wood, some of which likely involve time frames similar to 200–500-year flood-plain half-lives. On the upper Quinault River and Queets River, log jams promote bar growth and consequent channel shifting, short-distance avulsions, and meander cutoffs, resulting in mobile and wide active channels. On the lower Quinault River, large portions of the channel are stable and flow within vegetated flood plains. However, locally, channel-spanning log jams have caused channel avulsions within reaches that have been subsequently mobile for several decades. In all three reaches, log jams appear to be areas of conifer germination and growth that may later further influence channel and flood-plain conditions on long time scales by forming flood-plain areas resistant to channel migration and by providing key members of future log jams. Appreciation of these processes and dynamics and associated temporal and spatial scales is necessary to formulate effective long-term approaches to managing fluvial ecosystems in forested environments.

  14. Degree of Contamination and Sources of Polychlorinated Biphenyls in Meandering Road Creek and Woods Inlet of Lake Worth, Fort Worth, Texas, 2004 and 2006-07

    USGS Publications Warehouse

    Braun, Christopher L.; Wilson, Jennifer T.; Van Metre, Peter C.

    2008-01-01

    Lake Worth is a reservoir on the West Fork Trinity River on the western edge of Fort Worth, Texas. Air Force Plant 4 (AFP4) is on the eastern shore of Woods Inlet, an arm of Lake Worth that extends south from the main body of the lake. Two previous reports documented ele-vated polychlorinated biphenyl (PCB) concentrations in surficial sediment in Woods Inlet relative to those in surficial sediment in other parts of Lake Worth. This report presents the results of another USGS study, done in cooperation with the U.S. Air Force, to indicate the degree of PCB contamination of Meandering Road Creek and Woods Inlet and to identify possible sources of PCBs in Meandering Road Creek and Woods Inlet on the basis of suspended, streambed, and lake-bottom sediment samples collected there in 2004 and 2006-07. About 40 to 80 percent of total PCB concentrations (depending on how total PCB concentration is computed) in suspended sediment exceed the threshold effect concentration, a concentration below which adverse effects to benthic biota rarely occur. About 20 percent of total PCB concentrations (computed as sum of three Aroclors) in suspended sediment exceed the probable effect concentration, a concentration above which adverse effects to benthic biota are expected to occur frequently. About 20 to 30 percent of total PCB concentrations in streambed sediment exceed the threshold effect concentration; and about 6 to 20 percent of total PCB concentrations in lake-bottom (Woods Inlet) sediment exceed the threshold effect concentration. No streambed or lake-bottom sediment concentrations exceed the probable effect concentration. The sources of PCBs to Meandering Road Creek and Woods Inlet were investigated by comparing the relative distributions of PCB congeners of suspended sediment to those of streambed and lake-bottom sediment. The sources of PCBs were identified using graphical analysis of normalized concentrations (congener ratios) of 11 congeners. For graphical analysis, the

  15. The dynamics of a meandering coastal jet in the lee of a cape

    NASA Astrophysics Data System (ADS)

    Duarte, Rui; Carton, Xavier; Poulin, Francis J.

    2016-05-01

    In a barotropic model of an oceanic channel, bounded to the north by a straight coast indented by a Gaussian cape, the evolution of a coastal jet is studied numerically. In the absence of the cape, the barotropic instability of the jet is determined. In the presence of the cape, a regular row of meanders develops downstream of this feature, and becomes stationary for a particular range of parameters. The relevant parameters are the velocity and width of the jet, size of the cape, and beta effect. The formation of meanders occurs first via the instability of the jet, then via the generation of vorticity anomalies at the cape, which are advected both downstream by the flow and offshore by the radiation of Rossby waves. Once the meanders are established, they remain stationary features if the propagation velocity of the meanders (due to the dipolar effect at the coast) opposes the jet velocity and the phase speed of the wave on the vorticity front. Finally, a steady state of a regular row of meanders is also obtained via a matrix method and is similar to that obtained in the time-dependent case.

  16. Absolute and convective instabilities and their roles in the forecasting of large frontal meanderings

    NASA Astrophysics Data System (ADS)

    Liang, X. San; Robinson, Allan R.

    2013-10-01

    Frontal meanderings are generally difficult to predict. In this study, we demonstrate through an exercise with the Iceland-Faeroe Front (IFF) that satisfactory predictions may be achieved with the aid of hydrodynamic instability analysis. As discovered earlier on, underlying the IFF meandering is a convective instability in the western boundary region followed by an absolute instability in the interior; correspondingly the disturbance growth reveals a switch of pattern from spatial amplification to temporal amplification. To successfully forecast the meandering, the two instability processes must be faithfully reproduced. This sets stringent constraints for the tunable model parameters, e.g., boundary relaxation, temporal relaxation, eddy diffusivity, etc. By analyzing the instability dispersion properties, these parameters can be rather accurately set and their respective ranges of sensitivity estimated. It is shown that too much relaxation inhibits the front from varying; on the other hand, too little relaxation may have the model completely skip the spatial growth phase, leading to a meandering way more upstream along the front. Generally speaking, dissipation/diffusion tends to stabilize the simulation, but unrealistically large dissipation/diffusion could trigger a spurious absolute instability, and hence a premature meandering intrusion. The belief that taking in more data will improve the forecast does not need to be true; it depends on whether the model setup admits the two instabilities. This study may help relieve modelers from the laborious and tedious work of parameter tuning; it also provides us criteria to distinguish a physically relevant forecast from numerical artifacts.

  17. Restoration of rivers and streams

    SciTech Connect

    Gore, J.A.

    1985-01-01

    All of the major topics which must be addressed when considering reclamation of a river ecosystem are detailed. Specific chapters deal with hydrologic considerations, including the estimation of meander patterns as well as geomorphic considerations of runoff patterns. Also covered are the preservation and restoration of water quality, as well as biological techniques for restoration of riparian vegetation, habitat enhancement for benthic invertebrates and fisheries, and methods for determining successful biotic restoration.

  18. A multifaceted approach to prioritize and design bank stabilization measures along the Big Sioux River, South Dakota, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multifaceted approach was used to manage fine-grained sediment loadings from river bank erosion along the Big Sioux River between Dell Rapids and Sioux Falls, South Dakota, USA. Simulations with the RVR Meander and CONCEPTS river-morphodynamics computer models were conducted to identify stream-ban...

  19. Alterations of channel parameters in response to river regulation works since 1840 on the Lower Tisza River (Hungary)

    NASA Astrophysics Data System (ADS)

    Kiss, Tímea; Fiala, Károly; Sipos, György

    2008-06-01

    In the last few years an increase in the frequency and magnitude of floods was detected on the Tisza River, endangering large areas of Hungary. The causes of these record floods were complex, including both natural and human induced factors. This paper focuses on river management works and their effect on planimetric and cross-sectional parameters, with special attention to the flood conductivity changes to the river channel. During 19th century river regulation works, half of the total length of the Tisza River was altered by cut-offs, while in the 20th century mostly revetments and groynes were constructed. Subsequently, horizontal and vertical channel parameters have changed considerably due to semi-natural bed processes. In order to reveal changes, hydrological map series (1842, 1890, 1929, 1957, 1976 and 1999) and cross-sectional surveys from the same dates were analysed. Prior to the intensive human interventions (before 1890s) the river's course was highly sinuous with some very sharp bends. Due to cut-offs both the length and sinuosity of the Tisza River decreased by 35%, while the lengths of straight sections and the river's slope doubled. As a consequence the river incised by up to 3.8 m until the 1929 survey, resulting better flood conductivity, which improved flood safety. In the 1920s river management favoured bank stabilisation in order to stop the lateral migration of the channel. Despite these measures, meander development has continued, however, in a distorted manner. This is reflected by the opposing processes of lengthening centre-line on the one hand and gradually decreasing radius of curvature on the other. These processes can be explained by the continuous development of natural point-bars on the convex bank, and the lack of lateral retreat on the concave stabilised bank. The width of the river decreased by 17-45%, while its mean and maximum depth increased by 5-48%. The area of cross-sections influenced by revetments decreased by 6

  20. Response of extratropical cyclone activity to the Kuroshio large meander in northern winter

    NASA Astrophysics Data System (ADS)

    Hayasaki, Masamitsu; Kawamura, Ryuichi; Mori, Masato; Watanabe, Masahiro

    2013-06-01

    We examined possible responses of cyclone activities to the bimodal path states of the Kuroshio Current [i.e., large meander (LM) and non-LM (NLM)] by using the long-term reanalysis data and the 20th century hindcast experiment of a high-resolution atmosphere-ocean coupled model. Compared with a seasonal mean cyclone track frequency for the LM and NLM periods, a primary cyclone track shifts southward in association with the meander of Kuroshio Current. Composite analyses of the hindcast experiment showed remarkable atmospheric responses accompanying the Kuroshio LM. The Kuroshio LM causes a decrease in latent heat flux in the south of Japan and a southward shift of the near-surface baroclinic zone. Distinctive decreases in thermodynamic fluxes inhibit the rapid development of cyclones in the meander region, eventually inducing positive sea level pressure anomalies downstream from that region.

  1. Improved numerical modeling of morphodynamics of rivers with steep banks

    NASA Astrophysics Data System (ADS)

    Langendoen, Eddy J.; Mendoza, Alejandro; Abad, Jorge D.; Tassi, Pablo; Wang, Dongchen; Ata, Riadh; El kadi Abderrezzak, Kamal; Hervouet, Jean-Michel

    2016-07-01

    The flow and sediment transport processes near steep streambanks, which are commonly found in meandering, braided, and anastomosing stream systems, exhibit complex patterns that produce intricate interactions between bed and bank morphologic adjustment. Increasingly, multi-dimensional computer models of riverine morphodynamics are used to aid in the study of these processes. A number of depth-averaged two-dimensional models are available to simulate morphologic adjustment of both bed and banks. Unfortunately, these models use overly simplified conceptual models of riverbank erosion, are limited by inflexible structured mesh systems, or are unable to accurately account for the flow and sediment transport adjacent to streambanks of arbitrary geometry. A new, nonlinear model is introduced that resolves these limitations. The model combines the river morphodynamics computer models TELEMAC-2D and SISYPHE of the open source TELEMAC-MASCARET suite of solvers with the bank erosion modules of the CONCEPTS channel evolution computer model. The performance of the new model is evaluated for meander-planform initiation and development. The most important findings are: (1) the model is able to simulate a much greater variety and complexity in meander wavelengths; (2) simulated meander development agrees closely with the unified bar-bend theory of Tubino and Seminara (1990); and (3) the rate of meander planform adjustment is greatly reduced if the wavelength of alternate bars is similar to that of meanders.

  2. Quantitative Measurements of Bedform Transport Rates and Sand Sheet Character in the Lower Mississippi River

    NASA Astrophysics Data System (ADS)

    Nittrouer, J. A.; Allison, M. A.; Campanella, R.

    2005-05-01

    Channel sand volume and downstream flux in the Mississippi River have important implications for proposed mitigation projects (dredging and pipelines) that seek to utilize this resource for replenishing neighboring barrier islands and restoring Louisiana's deteriorating wetlands. This study quantifies bedform migration-induced sand flux through the lower river on daily and seasonal timescales, and evaluates the sedimentary character of the bedload component. Observations and measurements were conducted along three study grids (Audubon Park, English Turn and Venice) over a range of river discharges between April 2003 and January 2005. Two multibeam bathymetric profiles of the study grids were conducted 24 h apart to document bedform migration, and stratigraphy and thickness of the sand layer were confirmed by CHIRP seismic profiling. Downstream transport is evaluated from bed elevation changes for a 1 m grid after correcting for river stage, and utilized to calculate bedload sand fluxes for larger, averaged grid cells after visual examination confirmed dunes had migrated <1 wavelength. Algorithms were formulated to remove spurious grid cells created by vessel motion, navigation and swath-matching errors. Initial data analysis indicates flux rates conform to expected trends: values are proportional to river discharge and are higher in the channel thalweg of straight reaches relative to shallower water. Bedform size also increases with river discharge and spatial changes in flux rates; height ranges from <1 m to 10 m, and wavelength from 10 m to 100 m. Seasonal trends in sand sheet thickness are evident, particularly in deeper meander reaches, where aggradation occurs at low flow and scour is observed during high flow. At highest discharges observed (35,000 m3/sec), bedform troughs bottom out on exposed relict fluvio-deltaic strata that the river has incised (i.e., sediment starved). A spatially uniform grab sampling effort (250 samples) provided grain size data of

  3. Imaging beneath the skin of large tropical rivers: Clay controls on system morphodynamics revealed by novel CHIRP sub-surface sonar and deep coring along the Fly and Strickland Rivers, Papua New Guinea (Invited)

    NASA Astrophysics Data System (ADS)

    Aalto, R. E.; Grenfell, M.; Lauer, J. W.

    2010-12-01

    Tropical rivers dominate Earth’s fluvial fluxes for water, carbon, and mineral sediment. They are characterized by large channels and floodplains, old system histories (in comparison to many temperate rivers), frequent and prolonged periods of flooding, and a clay-dominated sediment flux transported above a sandy bed. However, limited insight is available regarding the underlying bed & floodplain strata -- material that underpins system mobility and morphodynamics. Available data commonly stems from “skin-deep” approaches such as GIS analysis of imagery, shallow sampling of a surface veneer, & topographic profiling during lower river stages. Given the large temporal & spatial scales of such systems, new approaches are needed to see below lag deposits on mobile sandy beds & deep into expansive floodbasins. Furthermore, such data are needed to test whether we can usefully interpret large tropical river morphology using direct analogies to observations from small temperate sytems. Systems responding to sea level rise, pending avulsions, or an increase/contrast in sediment load would provide especially valuable insight. We conducted a field campaign along the Fly and Strickland Rivers in Papua New Guinea (discharge ~ 5,400 CMS). Immediate results were obtained using a dual-frequency CHIRP sub-bottom profiler optimized for fluvial environments, with which we were able to image 10-20m below the river/lake bed. We were able to distinguish sandy deposits from harder clay and silt lenses and also collected bed grab samples to verify our sonar results. Deep borehole samples (5-15m), push cores, and cutbank profiles of material strength confirmed observations from the sonar profiling. We simultaneously collected side-scan sonar imagery plus DGPS water/bed elevations. Findings include: 1) The prevalence of hard clay beneath the bed at many locations along the Lower Fly and Strickland Rivers, retarding migration; 2) Unusual bed morphology along the lower Middle Fly River

  4. The city and the river A reconstruction of the strategical position of early 9th century Dorestad, The Netherlands

    NASA Astrophysics Data System (ADS)

    Kosian, Menne; Weerts, Henk; Steur, Roeland; Abrahamse, Jaap-Evert

    2013-04-01

    Why was the Early-medieval trade-port of Dorestad located at a relatively inland position in the Rhine delta and not at the coast, as one would expect? We combined palaeogeographical, environmental-archaeological, geomorphological/geological and laser-altimetry data to propose an answer to this question. Local Dorestad data had to be combined with a regional paleogeographical reconstruction of active river branches in the 9th-century Rhine delta to come to a satisfactory answer. The location of Dorestad on a high natural levee along a relatively stable navigable branch of the Rhine in the central Rhine delta was perfect for trade. The high levee gave protection from the annual river floods. Although this branch of the Rhine was fairly stable in the heydays of Dorestad, the meanders near Dorestad slowly migrated. Excavations at Dorestad show that the harbour works of Dorestad were constantly adapted to this migration, thereby following the meander on which they were located. Ships could reach the port from the sea through at least three navigable Rhine branches: the Lek, the Old Rhine and the Vecht rivers. Dorestad was thus easily accessible and yet far enough from the coast to be safe from storm floods - but was it located at its specific location for these reasons alone? We combined existing geomorphological and geological maps with recent nation-wide laser-altimetry (AHN, General Elevation model of the Netherlands') for a regional palaeogeographical reconstruction of 9th-century active Rhine branches in a GIS. This reconstruction revealed that river connections with the Flemish, French and German hinterland were perfect. Other delta branches ensured safe connections to the Zeeland delta and the open Flemish coast, all the way to Dover Straight to the south and to the open Frisian coast all the way to present Southern Denmark in the North. The dangerously closed coast of Holland without any safe shelter places for storms could thus be avoided by ships coming in

  5. Lake Murray, Fly and Strickland River Basins, Papua, New Guinea

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Lake Murray, a manmade reservoir, lies between the Fly and Strickland River Basins, Papua, New Guinea (7.0S, 141.5E). The region, photographed in sunglint, shows the water level in the reservoir and the full extent of the drainage basins of both river systems as the rivers meander through wide alluvial floodplains. Some forest clearing can be seen in places throughout the region, but most of the area remains in closed canopy forest.

  6. Flood plain and channel dynamics of the Quinault and Queets Rivers, Washington, USA

    NASA Astrophysics Data System (ADS)

    O'Connor, Jim E.; Jones, Myrtle A.; Haluska, Tana L.

    2003-03-01

    -plain half-lives of 300 to 500 years. Observations from this study and previous studies on the Queets River show that channel and flood-plain dynamics and morphology are affected by interactions between flow, sediment, and standing and entrained wood, some of which likely involve time frames similar to 200-500-year flood-plain half-lives. On the upper Quinault River and Queets River, log jams promote bar growth and consequent channel shifting, short-distance avulsions, and meander cutoffs, resulting in mobile and wide active channels. On the lower Quinault River, large portions of the channel are stable and flow within vegetated flood plains. However, locally, channel-spanning log jams have caused channel avulsions within reaches that have been subsequently mobile for several decades. In all three reaches, log jams appear to be areas of conifer germination and growth that may later further influence channel and flood-plain conditions on long time scales by forming flood-plain areas resistant to channel migration and by providing key members of future log jams. Appreciation of these processes and dynamics and associated temporal and spatial scales is necessary to formulate effective long-term approaches to managing fluvial ecosystems in forested environments.

  7. Quantifying Morphologic Changes in a Low Gradient River Crossing Southeast Louisiana Fault Zones

    NASA Astrophysics Data System (ADS)

    Fischer, G.; Gasparini, N. M.; Dawers, N. H.

    2011-12-01

    This study investigates the signature of faulting in low gradient, alluvial rivers crossing the Baton Rouge fault zone (BRFZ) and Denham Springs-Scotlandville fault zone (DSSFZ), which encompass a set of East-West striking normal faults in southeast Louisiana. These faults exhibit surface expressions associated with up to a few meters of vertical displacement of Late Pleistocene sediments, but little is known about their activity during the Holocene. Our study aims to quantify geomorphic changes in a number of rivers that cross these fault zones and to use these changes to gain insight into the history of faulting in the region. We hypothesize that fault movement will be evident in patterns of river sinuosity, slope, and width to depth ratio. We focus on four subparallel channels of various discharges that cross either or both the BRFZ and the DSSFZ. Information on local fault scarp heights and channel reaches are extracted by GIS analysis of the LA LiDAR 5 m DEM, as well as flow modeling using the HEC-RAS software program. On the Tickfaw River, we conducted field surveys using differential GPS to record contemporary water surface slopes and channel location. Historic channel features on the Tickfaw are characterized using a series of aerial photographs dating back to 1952. Over the past 50 years, the Tickfaw River has shortened its course through the study area significantly (~4.9%) by means of meander cutoffs. Since 1952, sinuosity (P) has decreased in all of the Tickfaw channel reaches that cross fault segments. Currently, the sinuosity is extremely low (average P = 1.14) where the river crosses the DSSFZ and slightly higher where the river crosses the BRFZ (average P = 1.9). We use the LiDAR data to quantify offset on the faults that the river crosses. These values will be compared with the average lateral migration rate of the river in order to better understand the time scales over which both processes operate. If the faults appear to have little morphologic

  8. Return migration.

    PubMed

    Gmelch, G

    1980-01-01

    The author reviews the findings of the growing literature on return migration. Topics covered include typologies of return migrants, reasons for return, adaptation and readjustment of returnees, and the impact of return migration on the migrants' home societies. The focus of the study is on international return migration, migration to Northern Europe and northeastern North America, and return migration to the southern and eastern fringes of Europe and the Caribbean

  9. Mobilization of Floodplain Sediments by Chute Cutoffs on a Large River: Lower Wabash River, Illinois-Indiana

    NASA Astrophysics Data System (ADS)

    Zinger, J. A.; Rhoads, B. L.; Best, J.; Engel, F.; Konsoer, K. M.

    2010-12-01

    Bend cutoffs are a common mechanism of morphologic change in all scales of meandering rivers worldwide. Cutoffs can develop either by progressive migration of an elongated bend onto itself, forming a neck cutoff, or by erosion of a new channel across the neck of a bend, producing a chute cutoff. In contrast to the slow processes of “shaving” of the floodplain by outer bank erosion or formation of neck cutoffs by lateral channel migration, the sudden development of a chute cutoff channel can rapidly introduce a large volume of floodplain sediment into the downstream river channel. Formation of a chute cutoff channel also occurs on much shorter timescales than infilling of the subsequent oxbow lake. The asynchronous nature of such floodplain sediment release and storage resulting from cutoffs has important implications for longer-term floodplain sediment balance and the accurate modeling of floodplain evolution and architecture. In this study, using aerial photography and ground survey, we quantified the quantity of floodplain sediment mobilized by two chute cutoff events on Mackey Bend, a large, elongated meander of the lower Wabash River, IL-IN, located just upstream of the Ohio River confluence. A chute cutoff channel on this bend developed during flooding in June 2008 and was followed by formation of a second cutoff channel in July 2009. Here, we compare the volume of sediment released by these cutoff events to the background flux of sediment generated by lateral migration of the bend in the previous 78 years. Our study also explores the influence of these cutoff events on the morphology of the Wabash-Ohio confluence immediately downstream of the evolving chute cutoff channels. We found that, in just over two years, these cutoffs released c. 3. 6 million cubic meters of floodplain sediment, which is comparable to 4.6% of the annual sediment load of the Mississippi River. According to our calculations, it would take over 60 years of lateral migration of Mackey

  10. Fabrication of superconducting NbN meander nanowires by nano-imprint lithography

    NASA Astrophysics Data System (ADS)

    Mei, Yang; Li-Hua, Liu; Lu-Hui, Ning; Yi-Rong, Jin; Hui, Deng; Jie, Li; Yang, Li; Dong-Ning, Zheng

    2016-01-01

    Superconducting nanowire single photon detector (SNSPD), as a new type of superconducting single photon detector (SPD), has a broad application prospect in quantum communication and other fields. In order to prepare SNSPD with high performance, it is necessary to fabricate a large area of uniform meander nanowires, which is the core of the SNSPD. In this paper, we demonstrate a process of patterning ultra-thin NbN films into meander-type nanowires by using the nano-imprint technology. In this process, a combination of hot embossing nano-imprint lithography (HE-NIL) and ultraviolet nano-imprint lithography (UV-NIL) is used to transfer the meander nanowire structure from the NIL Si hard mold to the NbN film. We have successfully obtained a NbN nanowire device with uniform line width. The critical temperature (Tc) of the superconducting NbN meander nanowires is about 5 K and the critical current (Ic) is about 3.5 μA at 2.5 K. Project supported by the National Basic Research Program of China (Grant Nos. 2011CBA00106 and 2009CB929102) and the National Natural Science Foundation of China (Grant Nos. 11104333 and 10974243).

  11. Distributions of pigments and primary production in a Gulf Stream meander

    SciTech Connect

    Lohrenz, S.E.; Cullen, J.J.; Phinney, D.A.; Olson, D.B.; Yentsch, C.S.

    1993-08-15

    An investigation was made of physical effects of Gulf Stream meandering on the vertical and horizontal distributions of photosynthetic pigments and primary production. Cruises were conducted in the vicinity of a meander east of 73{degrees}W and north of 37{degrees}N from September 21 to October 5 (leg 1) and October 12-21, 1988 (leg 2), on the R/V Cape Hatteras. Relationships of photosynthesis (normalized to chlorophyll) to irradiance (P-I) did not show large horizontal variation, and water column composite P-I curves from leg 1 and leg 2 were similar. Therefore, a single P-I curve derived from pooled data was used to model distributions of primary production. Distributions of photosynthetic pigments were characterized on the basis of in vivo fluorescence profiles and empirical relationships with extracted pigment concentrations. Subsurface irradiance was described using a spectral irradiance model. Cross sections of the Gulf Stream revealed consistently higher pigment concentrations and primary production on the slope water side. Along-stream variations in pigment distributions and primary production were apparently related to density structure influenced by meander circulation. Such variations were less pronounced during leg 2, which came after a transition from a well-defined meander interacting with a warm-core ring (leg 1) to a more linear stream (leg 2). Higher water-column-integrated primary production during leg 2 was attributed to mixing-induced nutrient injection and redistribution of chlorophyll in the photic zone. 47 refs., 13 figs., 2 tabs.

  12. Channel Stability and Water Quality of the Alagnak River, Southwestern Alaska

    USGS Publications Warehouse

    Curran, Janet H.

    2003-01-01

    The Alagnak River, a National Wild River located in southwestern Alaska, drains an area of 3,600 square kilometers and is used for recreational and subsistence activities, primarily angling, camping, rafting, and hunting by visitors and seasonal residents, and for commercial guiding by several lodges. Increases in visitor use in the 1990s included an increase in the use of high-horsepower motorboats on the river, primarily for angling, and raised concerns regarding human impacts on water quality. Downstream from its confluence with the Nonvianuk River at river kilometer (RK) 93, the Alagnak River is formed in glacial drift and outwash with a single, low bedrock outcrop. Analysis of aerial photography from 1951, 1982, and 2001 shows that the river's multiple channels from RK 57 to 93 have been relatively stable. In contrast, long reaches of multiple channels from RK 35 to 57 changed substantially between 1951 and 1982, creating a new complex of channels. Downstream from RK 35, channel changes in the past 50 years consist largely of minor meander migration. Analysis of water samples collected during this study at RK 21, 46, and 93 and in the Alagnak and Nonvianuk Rivers at the outlets of the lakes that form their source shows that the Alagnak River is a nutrient-poor, calcium-bicarbonate water with low suspended-sediment concentrations. Water chemistry changes little over time or in a downstream direction. Weak patterns over time include high late May/early June concentrations of some nutrients, carbon, and iron. Weak patterns over distance include downstream increases in iron, manganese, and phosphorous. No pervasive human impacts on Alagnak River water chemistry were detected. Local effects that could be diluted within a kilometer downstream of the source were not detectable by this study. Data collected at three continuously recording wake gaging stations at RK 21, 46, and 93 showed that 1999-2000 motorboat use was heaviest in the lower reaches of the river

  13. THE GAPS BETWEEN AN INTEGRATED UNDERSTANDING OF CHANNELIZATION, HYDROLOGY AND WATER QUALITY VERSUS HOLISTIC FUTURE MANAGEMENT: A CASE STUDY OF THE WILLAMETTE RIVER, OREGON

    EPA Science Inventory

    Over the last 150 years the main channel of the Willamette River has been drastically altered by human activity. It has changed from a generally meandering and anastamosing river with extensive reaches of broad, active and connected flood plain features to a river with 13 major ...

  14. Assessing fish predation on migrating juvenile steelhead and a retrospective comparison to steelhead survival through the Priest Rapids Hydroelectric Project, Columbia River, Washington, 2009-11

    USGS Publications Warehouse

    Hardiman, Jill M.; Counihan, Timothy D.; Burgess, Dave S.; Simmons, Katrina E.; Holmberg, Glen S.; Rogala, Josh; Polacek, Rochelle

    2012-01-01

    The U.S. Geological Survey (USGS) and the Washington Department of Fish and Wildlife (WDFW) have been working with the Public Utility District No. 2 of Grant County, Washington (Grant PUD), to increase their understanding of predator-prey interactions in the Priest Rapids Hydroelectric Project (PRP), Columbia River, Washington. For this study, the PRP is defined as the area approximately 6 kilometers upstream of Wanapum Dam to the Priest Rapids Dam tailrace, 397.1 miles from the mouth of the Columbia River. Past year’s low survival numbers of juvenile steelhead (Oncorhynchus mykiss) through Wanapum and Priest Rapids Dams has prompted Grant PUD, on behalf of the Priest Rapids Coordinating Committee, to focus research efforts on steelhead migration and potential causal mechanisms for low survival. Steelhead passage survival in 2009 was estimated at 0.944 through the Wanapum Development (dam and reservoir) and 0.881 through the Priest Rapids Development and for 2010, steelhead survival was 0.855 for Wanapum Development and 0.904 for Priest Rapids Development. The USGS and WDFW implemented field collection efforts in 2011 for northern pikeminnow (Ptychocheilus oregonensis), smallmouth bass (Micropterus dolomieu), and walleye (Sander vitreus, formerly Stizostedion vitreum) and their diets in the PRP. For predator indexing, we collected 948 northern pikeminnow, 237 smallmouth bass, 18 walleye, and two largemouth bass (Micropterus salmoides). The intent of this study was to provide standardized predation indices within individual reaches of the PRP to discern spatial variability in predation patterns. Furthermore, the results of the 2011 study were compared to results of a concurrent steelhead survival study. Our results do not indicate excessively high predation of Oncorhynchus spp. occurring by northern pikeminnow or smallmouth bass in any particular reach throughout the study area. Although we found Oncorhynchus spp. in the predator diets, the relative

  15. Determination of real-time predictors of the wind turbine wake meandering

    NASA Astrophysics Data System (ADS)

    Muller, Yann-Aël; Aubrun, Sandrine; Masson, Christian

    2015-03-01

    The present work proposes an experimental methodology to characterize the unsteady properties of a wind turbine wake, called meandering, and particularly its ability to follow the large-scale motions induced by large turbulent eddies contained in the approach flow. The measurements were made in an atmospheric boundary layer wind tunnel. The wind turbine model is based on the actuator disc concept. One part of the work has been dedicated to the development of a methodology for horizontal wake tracking by mean of a transverse hot wire rake, whose dynamic response is adequate for spectral analysis. Spectral coherence analysis shows that the horizontal position of the wake correlates well with the upstream transverse velocity, especially for wavelength larger than three times the diameter of the disc but less so for smaller scales. Therefore, it is concluded that the wake is actually a rather passive tracer of the large surrounding turbulent structures. The influence of the rotor size and downstream distance on the wake meandering is studied. The fluctuations of the lateral force and the yawing torque affecting the wind turbine model are also measured and correlated with the wake meandering. Two approach flow configurations are then tested: an undisturbed incoming flow (modelled atmospheric boundary layer) and a disturbed incoming flow, with a wind turbine model located upstream. Results showed that the meandering process is amplified by the presence of the upstream wake. It is shown that the coherence between the lateral force fluctuations and the horizontal wake position is significant up to length scales larger than twice the wind turbine model diameter. This leads to the conclusion that the lateral force is a better candidate than the upstream transverse velocity to predict in real time the meandering process, for either undisturbed (wake free) or disturbed incoming atmospheric flows.

  16. Wake meandering statistics of a model wind turbine: Insights gained by large eddy simulations

    NASA Astrophysics Data System (ADS)

    Foti, Daniel; Yang, Xiaolei; Guala, Michele; Sotiropoulos, Fotis

    2016-08-01

    Wind tunnel measurements in the wake of an axial flow miniature wind turbine provide evidence of large-scale motions characteristic of wake meandering [Howard et al., Phys. Fluids 27, 075103 (2015), 10.1063/1.4923334]. A numerical investigation of the wake, using immersed boundary large eddy simulations able to account for all geometrical details of the model wind turbine, is presented here to elucidate the three-dimensional structure of the wake and the mechanisms controlling near and far wake instabilities. Similar to the findings of Kang et al. [Kang et al., J. Fluid Mech. 744, 376 (2014), 10.1017/jfm.2014.82], an energetic coherent helical hub vortex is found to form behind the turbine nacelle, which expands radially outward downstream of the turbine and ultimately interacts with the turbine tip shear layer. Starting from the wake meandering filtering used by Howard et al., a three-dimensional spatiotemporal filtering process is developed to reconstruct a three-dimensional meandering profile in the wake of the turbine. The counterwinding hub vortex undergoes a spiral vortex breakdown and the rotational component of the hub vortex persists downstream, contributing to the rotational direction of the wake meandering. Statistical characteristics of the wake meandering profile, along with triple decomposition of the flow field separating the coherent and incoherent turbulent fluctuations, are used to delineate the near and far wake flow structures and their interactions. In the near wake, the nacelle leads to mostly incoherent turbulence, while in the far wake, turbulent coherent structures, especially the azimuthal velocity component, dominate the flow field.

  17. How do big rivers come to be different?

    NASA Astrophysics Data System (ADS)

    Ashworth, Philip J.; Lewin, John

    2012-08-01

    environments are common, with water bodies that vary from smaller water-filled swales and palaeochannels, to floodbasins and km-scale linear lakes in sediment-dammed tributaries. Organic sedimentation is significant along relatively sediment-poor and laterally-stable large rivers that fail to fill their alluvial corridors. Three case studies are used to illustrate this variability in big river pattern and process: the Ob, Jamuna and Paraná. These rivers are respectively dominated by meandering, braiding and mixed mainstream and accessory channel morphologies. Big rivers have some processes and patterns that are different from smaller rivers including: (i) no simple down-valley sequence in control variables and channel pattern, (ii) main channels with high width:depth ratios, (iii) few or no channel-wide unit bars migrating through the main thalwegs, (iv) extensive and low-gradient floodplains that provide space for channel shifting and floodplain sedimentation, (v) long distances between significant tributaries to allow full mixing of water and sediment discharges, (vi) in some places, partially-decoupled channels and floodplains, and (vii) significant floodplain water bodies that readily act as sinks for fine-grained sediment where this is supplied, or organic deposition. Although understanding of contemporary big river patterns requires attention to a range of timescales, including inheritance from sediments of Quaternary age, big rivers do have a distinctive character. The variety of patterns on big rivers may usefully be viewed in terms of sediment systems operating at both the catchment and reach scales. Intra-river variability and internal complexity show the need to understand contrasted sediment supply, through-put and alluvial exchange as determinants of big river morphology and pattern.

  18. Influence of Large Woody Debris on Three-dimensional Flow Structure Through Meander Bends in a Low-energy Stream

    NASA Astrophysics Data System (ADS)

    Newell, M. D.; Rhoads, B. L.

    2001-05-01

    Most theoretical research on the dynamics of meandering streams has emphasized the importance of internal mechanisms. Although there is an abundance of empirical work on external factors, theoretical development in this area has been limited, especially for biotic factors, such as LWD, which geomorphologists have long recognized constitute important external mechanisms in fluvial systems. In particular, little is known about the role of LWD in low-energy, human-modified streams. One important potential morphological influence of LWD that has not been investigated is the potential for LWD to alter flow structures through meander bends, a critical element of current meander evolution theories since three dimensional characteristics of flow through meander bends have been shown to have a significant impact on the processes of sediment transport and bank erosion, and consequently meander development. The overall goal of this project is to advance the understanding of the interactions between large woody debris and the geomorphic structure and function of low-gradient meandering streams. This improved understanding will provide a more reliable framework of knowledge on which to base stream naturalization (i.e. the return to pre-disturbance conditions) and management plans for low-energy meandering streams with abundant LWD.

  19. Kootenai River Fisheries Investigations; Chapter 3 : Mainstem Habitat Use and Recruitment Estimates of Rainbow Trout, 1996 Annual Report.

    SciTech Connect

    Fredericks, James P.; Hendricks, Steve

    1997-09-01

    The objective of this study was to determine if recruitment is limiting the population of rainbow trout Oncorhynchus mykiss in the mainstem Kootenai River. The authors used snorkeling and electrofishing techniques to estimate juvenile rainbow trout density and total numbers in Idaho tributaries, and they trapped juvenile outmigrants to identify the age at which juvenile trout migrate from tributaries to the Kootenai River. The authors radio and reward-tagged post-spawn adult rainbow trout captured in Deep Creek to identify river reach and habitat used by those fish spawning and rearing in the Deep Creek drainage. They also conducted redd surveys in the Kootenai River to determine the extent of mainstem spawning. Based on the amount of available habitat and juvenile rainbow trout densities, the Deep Creek drainage was the most important area for juvenile production. Population estimates of age 0, age 1+, and age 2+ rainbow trout indicated moderate to high densities in several streams in the Deep Creek drainage whereas other streams, such as Deep Creek, had very low densities of juvenile trout. The total number of age 0, age 1+, and age 2+ rainbow trout in Deep Creek drainage in 1996 was estimated to be 63,743, 12,095, and 3,095, respectively. Radio telemetry efforts were hindered by the limited range of the transmitters, but movements of a radio-tagged trout and a returned reward tag indicated that at least a portion of the trout utilizing the Deep Creek drainage migrated downriver from the mouth of Deep Creek to the meandering section of river. They found no evidence of mainstem spawning by rainbow trout, but redd counting efforts were hindered by high flows from mid-April through June.

  20. From River Rambles to Museum Meanderings: Student Motivation and Service Learning.

    ERIC Educational Resources Information Center

    Elmer, Denise

    The prominence of experiential learning or service learning continues to grow in higher education. A 1999-2000 survey found that of 324 universities and colleges across the United States, 82% offer over 7,000 undergraduate level courses and over 700 graduate level courses in experiential or service learning. This paper considers the role of…

  1. Study of the anabranch dynamics for different sinuosity stages in the Upper Amazon River Basin

    NASA Astrophysics Data System (ADS)

    Frias, C. E.; Mendoza, A.; Dauer, K.; Abad, J. D.; Montoro, H.; Paredes, J.; Vizcarra, J.

    2013-12-01

    The Upper Peruvian Amazon River is characterized by a sequence of anabranching structures, which are composed by several channels behaving as non-developed and quasy-freely meandering channels. The widest channel in these anabranching structures is considered as the main channel or main anabranch while the other channels are secondary anabranches. Based on satellite imagery, it is observed that the main channels show different sinuosities along the Upper Peruvian Amazon River valley. Little is known about the effects of the planform characteristics of the main channel into the morphodynamics of the secondary anabranches. Thus, two study sites were selected to characterize anabranching structures with low and medium-high sinuosity main channels. For the low sinuosity main channel case, an area at the tri-point boundary between Colombia-Brazil and Peru was selected. For the medium-high sinuosity main channel case, an area upstream of Iquitos City (the largest city in the Peruvian Amazon Rainforest) was selected. A field campaign was carried out on 2010 and 2011 for the medium-high and low sinuosity stages respectively. On this field campaign velocity measurement, bathymetry and water surface elevations were obtained. With the field data it was possible to develop and validate a two dimensional shallow water numerical model to study the hydrodynamics on both sites. This allows us to discuss the effects of the current planform configuration of the anabranching structures into the short-term behavior of individual channels. In past studies, temporal analysis of the Amazon River planform have been carried out using satellite imagery with special focus into the floodplain, main channel, number of islands and valley slope. However, the dynamics in these anabranching structures containing multiple channels have not been studied in detailed. The metrics obtained for this study were sinuosity, channel width and annual migration rates. It was confirmed that in a medium to high

  2. The Lowland Rivers of The Netherlands - Geodiversity and Cultural Heritage on 19th and early 20th century Landscape Paintings

    NASA Astrophysics Data System (ADS)

    Jungerius, Pieter Dirk; van den Ancker, Hanneke; Moes, Constance

    2015-04-01

    One of the major Dutch landscapes is formed by lowland rivers. They divide the country in a southern and a northern part, both physically and culturally. We screened the freely available database of 19th and early 20th century paintings of Simonis & Buunk, www.simonis-buunk.com, looking for lowland river landscapes depicting geodiversity and cultural heritage relationships (See References for other landscapes). Emperor Napoleon declared The Netherlands as naturally belonging to his empire as its lands originated from muds originating in France and transported there by the big rivers. A description that may have given rise to the idea of the Netherlands as a delta, but from a geomorphological perspective The Netherlands consists of series of river plains of terrestrial origin, of which the north-western part are subsiding and invaded by the sea. Now, the rivers Meuse and Rhine (including its branches Waal and IJssel) meander through ever larger river plains before reaching the North Sea. They end in estuaries, something one would not expect of rivers with catchments discharging a large part of Western Europe. Apart from the geological subsidence, the estuaries might be due to human interference, the exploitation of peat and building of dikes since the 11th century, heavy storms and the strong tidal currents. Archaeological finds show Vikings and Romans already used the river Rhine system for trading and transporting goods. During the Roman Empire the Rhine was part of The Limes, the northern defence line of the empire. Romans already influenced the distribution of water over the different river branches. Since the middle of the 19th century groins and canalization drastically changed the character of the rivers. The 19th and early 20th century landscape paintings illustrate this change as well as changes in land use. Examples of geodiversity and cultural heritage relationships shown: - meanders and irregular banks disappear as river management increases, i.a. bends

  3. The Tritium Under-flow Study at the Savannah River Site

    SciTech Connect

    Hiergesell, Robert A.

    2008-01-15

    trans-river flow is eastward or westward depends primarily on the position of the Savannah River as it meanders back and forth within the flood plain and is limited to narrow sections of land adjacent to the river. With respect to the only location of westward trans-river flow that has a recharge area within the SRS, the new evaluations of hypothetical pumping scenarios indicated that only a very slight impact is incurred, even under the most extreme groundwater extraction scenario. The updated model did not result in a significant change in the location of the recharge areas at SRS and the only impact was measured in slight changes in the travel times associated with the travel path. The median groundwater travel times for particles released under each of the 4 groundwater extraction scenarios ranged from 366 to 507 years while. Under the most extreme scenario, that under which SRS groundwater extraction is discontinued, the shortest travel time was reduced from 90 to 79 years. It should be emphasized that the groundwater transit times do not include the time required for groundwater to migrate vertically downward across the uppermost aquifer (i.e. at the recharge area), thus the actual groundwater travel times could be up to several decades longer than what was calculated in the model. The exhaustive evaluations that have been conducted indicates that it is highly unlikely that tritiated groundwater originating at the SRS could migrate into Georgia and explain the low tritium activity levels that were originally observed in certain domestic water supply wells. Considering that those wells were located at some distance (several km) from the Savannah River, a far more likely explanation is that tritiated rainfall infiltrated the subsurface and recharged the shallow aquifer within which the well was finished.

  4. Numerical and experimental analysis of unidirectional meander-line coil electromagnetic acoustic transducers.

    PubMed

    Wang, Shujuan; Su, Riliang; Chen, Xiaoyang; Kang, Lei; Zhai, Guofu

    2013-12-01

    The elastic waves generated by traditional meander-line coil electromagnetic acoustic transducers (EMATs) propagate in two directions, overlapping the echo signals from defects with the same distances, and the defect echo signal is hard to distinguish from the edge-reflected signal when the EMATs are near the edge of a specimen. In this paper, a unidirectional EMAT with two meander-line coils is proposed. A finite element model is used to simulate the directivity of the Rayleigh and shear vertical waves generated by these EMATs. Six transducers are fabricated using the printed circuit technique. The unidirectional Rayleigh wave and shear vertical wave are tested, and the results agree well with the simulation.

  5. Cell Migration

    PubMed Central

    Trepat, Xavier; Chen, Zaozao; Jacobson, Ken

    2015-01-01

    Cell migration is fundamental to establishing and maintaining the proper organization of multicellular organisms. Morphogenesis can be viewed as a consequence, in part, of cell locomotion, from large-scale migrations of epithelial sheets during gastrulation, to the movement of individual cells during development of the nervous system. In an adult organism, cell migration is essential for proper immune response, wound repair, and tissue homeostasis, while aberrant cell migration is found in various pathologies. Indeed, as our knowledge of migration increases, we can look forward to, for example, abating the spread of highly malignant cancer cells, retarding the invasion of white cells in the inflammatory process, or enhancing the healing of wounds. This article is organized in two main sections. The first section is devoted to the single-cell migrating in isolation such as occurs when leukocytes migrate during the immune response or when fibroblasts squeeze through connective tissue. The second section is devoted to cells collectively migrating as part of multicellular clusters or sheets. This second type of migration is prevalent in development, wound healing, and in some forms of cancer metastasis. PMID:23720251

  6. Development of a modular MR valve using meandering flow path structure

    NASA Astrophysics Data System (ADS)

    Ichwan, B.; Mazlan, S. A.; Imaduddin, F.; Ubaidillah; Koga, T.; Idris, M. H.

    2016-03-01

    The extensive development of the magnetorheological (MR) valve has successfully introduced a new high-performance compact-class MR valve using a meandering flow path structure. Aside from the performance improvement, in real applications, the ease of performance adjustment also needs to be improved. This study focused on the development of a new design of a modular MR valve using a meandering flow path to improve the adjustability of the valve performance. The approach is proposed based on the high-performance advantages of a meandering flow path structure, while at the same time utilizing the benefit of the modular structure in terms of performance flexibility. In order to evaluate the performance of the modular structure, the analytical assessment was conducted for three different module stages: the single-stage module, the double-stage module, and triple-stage module. To predict the strength of the magnetic field in the effective area, the magnetic simulation was conducted through an open-source software called the FEMM (Finite Element Method Magnetics). The quasi-steady mathematical model of the proposed valve was also derived to conduct the analytical assessment as well as to predict the valve performance. In order to validate the simulation results, the prototypes of the proposed valve are experimentally tested with the aid of the hydraulic cylinder on a dynamic test machine. The results of the MR valve assessment from both the simulation and experimental test demonstrated that the pressure drop rating of the meandering type MR valve can be easily modified using modular structure by changing the number of module stages.

  7. Beyond Cross Sections; LiDAR in Support of Sprague River geomorphology Studies, Klamath Basin, Oregon

    NASA Astrophysics Data System (ADS)

    O'Connor, J. E.; McDowell, P. F.; Lind, P.; Haluska, T.; Jackson, K.

    2007-12-01

    LiDAR terrain data was collected in November 2004 for 750 square kilometers of the Sprague River valley, Oregon, by Watershed Sciences, Inc., under contract with the Klamath Tribes. This coverage, obtained to support multiple ecologic analysis and restoration activities in the Klamath Basin, encompasses about 90 km of valley- bottom corridor for the main Sprague River as well as downstream alluvial sections of principal tributaries, including 15 km of the Sycan River, 15 km of the South Fork Sprague River, and 10 km of the North Fork Sprague River. Acquisition conditions were leaf-off at normal fall low flow. Assessment of the vertical divergence between 967 surveyed points and the laser points gave a RMSE of 0.052 m with a standard deviation of 0.051 m. The resulting bare-earth 1-m grid has been used for geomorphic mapping, paleo- and historical-channel mapping, qualitative and quantitative analysis of floodplain morphology, and assessment of channel incision over various timescales.4 Using the high resolution topography in combination with floodplain stratigraphy, we delineated the late Holocene (post 7.7 ka Mazama eruption) active floodplain. The morphology of this floodplain reveals processes locally important in forming the Sprague and Sycan river floodplains, including avulsion, meander abandonment and filling, lateral bar building, deposition by crevasses, and lateral migration. Mapping present and paleo-channel positions determined from historic photos and maps onto the LiDAR digital terrain model, coupled with augering to determine channel gravel depths, has allowed local assessment of long term channel incision and aggradation over the last several thousand years. Reaches of possible historic incision have also been delineated by comparing floodplain elevation to channel elevation in an essentially continuous manner along the valley corridor. This analysis reveals multiple reaches where the 1940 channel, as depicted on aerial photographs, is apparently

  8. A Modelling Framework to Assess the Effect of Pressures on River Abiotic Habitat Conditions and Biota

    PubMed Central

    Kail, Jochem; Guse, Björn; Radinger, Johannes; Schröder, Maria; Kiesel, Jens; Kleinhans, Maarten; Schuurman, Filip; Fohrer, Nicola; Hering, Daniel; Wolter, Christian

    2015-01-01

    River biota are affected by global reach-scale pressures, but most approaches for predicting biota of rivers focus on river reach or segment scale processes and habitats. Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions. In this study, a modelling framework was further developed and tested to assess the effect of pressures at different spatial scales on reach-scale habitat conditions and biota. Ecohydrological and 1D hydrodynamic models were used to predict discharge and water quality at the catchment scale and the resulting water level at the downstream end of a study reach. Long-term reach morphology was modelled using empirical regime equations, meander migration and 2D morphodynamic models. The respective flow and substrate conditions in the stu