River Reach Research Articles

Flow Modelling of Mahaweli River Reach with the Riverbed Intake of Udunuwara-Yatinuwara Water Supply Scheme

"ENGINEER", established in 1973 by The Institution of Engineers, is a Journal for dissemination of Engineering knowledge, published quarterly.If you are interested in contributing an Original Technical Paper based on research by the author(s) (intended for Section I) or an Original Article of Professional or Technical interest related to Engineering. (Section II) to this journal please go through the publication checklist which can be downloaded from here.Cover DescriptionCover images show a few views of Stage II of the Central Expressway from Mirigama to Kurunegala. The Institution of Engineers Sri Lanka acknowledges the Road Development Authority (RDA) for the images.

Synchrony of Seed Dispersal, Hydrology and Local Climate in a Semi-arid River Reach in California

The temporal availability of propagules is a critical factor in sustaining pioneer riparian tree populations along snowmelt-driven rivers because seedling establishment is strongly linked to seasonal hydrology. River regulation in semi-arid regions threatens to decouple seed development and dispersal from the discharge regime to which they evolved. Using the lower Tuolumne River as a model system, we quantified and modeled propagule availability for Populus fremontii (POFR), Salix gooddingii (SAGO), and Salix exigua (SAEX), the tree and shrub species that dominate near-channel riparian stands in the San Joaquin Basin, CA. A degree-day model was fit to field data of seasonal seed density and local temperature from three sites in 2002–2004 to predict the onset of the peak dispersal period. To evaluate historical synchrony of seed dispersal and seasonal river hydrology, we compared peak spring runoff timing to modeled peak seed release periods for the last 75 years. The peak seed release period began on May 15 for POFR (range April 23–June 10), May 30 for SAGO (range May 19–June 11) and May 31 for SAEX (range May 8–June 30). Degree-day models for the onset of seed release reduced prediction error by 40–67% over day-of-year means; the models predicted best the interannual, versus site-to-site, variation in timing. The historical analysis suggests that POFR seed release coincided with peak runoff in almost all years, whereas SAGO and SAEX dispersal occurred during the spring flood recession. The degree-day modeling approach reduce uncertainty in dispersal timing and shows potential for guiding flow releases on regulated rivers to increase riparian tree recruitment at the lowest water cost.

Scale Pattern Analysis Discriminates Atlantic Salmon by River Reach Rearing Origin

AbstractScale pattern analysis was used to discriminate among juvenile Atlantic salmon Salmo salar reared in different reaches of the Narraguagus River basin. Measurements of parr scales collected during 1990–1999 were used in a principal components analysis and to create linear discriminant functions for seven geographic strata and three river basin strata groups reflecting natural habitat breaks and Atlantic salmon management regimens. Discriminant functions were calculated with both pooled and annual data. Sufficient differentiation existed among rearing habitats of different reaches (or between geographically grouped reaches) in the Narraguagus River basin, particularly for tributary habitats, to allow discrimination to various degrees of possible use in management.

Spatial patterns of fish communities in the Upper Mississippi River System: assessing fragmentation by low‐head dams

AbstractWe assessed the similarity of fish communities among river reaches to assess community‐level fragmentation by low‐head dams in the Upper Mississippi River System (UMRS). The spatial coverage of standardized electrofishing sampling used in the Long Term Resource Monitoring Program (LTRMP) was extended for three of the six regional trend areas (RTA; pools 4, 13, and the Open River Reach) to include river reaches (outpools) immediately upstream and downstream from the standard RTA from 15 June to 31 October 2000. Additionally, pools 19 and 20 were sampled in September 2000. Cluster analysis and non‐metric multidimensional scaling of community composition and structure data revealed two major groups, upper and lower reaches, and four (for composition) or five (for structure) sub‐groupings of river reaches. In general, all outpools grouped with the nearest RTA for both community composition (no exception) and community structure (one exception). This suggests that fragmentation of fish communities from low‐head dams is minimal. Mantel correlations demonstrated strong inverse association between the similarity of fish communities with the distance between reaches. Habitat variables measured during electrofishing collections were significantly correlated with spatial variation of fish composition and community structure, but provided only marginal improvements to correlations with distance between reaches alone. Furthermore, habitat variability among river reaches also was related to distance between reaches. Determining the extent to which variation of fish communities is related to habitat or demographic processes (e.g. migration, larval drift, source‐sink dynamics) will be challenging for this system. Although low‐head dams on the UMRS may restrict movements for individuals and populations of certain fish species, we found little evidence that these effects have led to substantial, community‐level fragmentation. Copyright © 2006 John Wiley & Sons, Ltd.

The Effects of Scaling and Model Complexity in Simulating the Transport of Inorganic Micropollutants in a Lowland River Reach

Abstract A hypothesis stating that more complex descriptions of processes in models simulate reality better (less error) but with more unreliable predictability (more sensitivity) is tested using a river water quality model. This hypothesis was extended stating that applying the model on a domain of smaller scale requires greater complexity to capture the same accuracy as in large-scale model applications which, however, leads to increased model sensitivity. The sediment and pollutant transport model TOXI, a module in the WASP5 package, was applied to two case studies of different scale: a 90-km course of the 5th order (sensu Strahler 1952) lower Saale river, Germany (large scale), and the lock-and-weir system at Calbe (small scale) situated on the same river course. A sensitivity analysis of several parameters relating to the physical and chemical transport processes of suspended solids, chloride, arsenic, iron and zinc shows that the coefficient, which partitions the total heavy metal mass into its dissolved and sorbed fraction, is a very sensitive parameter. Hence, the complexity of the sorptive process was varied to test the hypotheses.

The Fish Community of a Flow-Impacted River Reach in Alabama, USA with Emphasis on Largemouth Bass and Spotted Bass

ABSTRACT The Weiss bypass reach of the Coosa River, Alabama, USA is a 32-km section of the river bypassed after construction of a power generation facility on Weiss Lake in 1961. This area experiences daily flow reversals that can extend 24 km upstream and increase depth by up to 2 m. During a 15-month period, we used electrofishing to collect 37 fish species from 10 families in this reach. Species richness and diversity increased with distance from the flow reversal, suggesting some influence of the daily flow reversals. However, because nearly all of the species collected were habitat generalists (i.e., none was a fluvial specialist), the flow appeared to influence the overall fish community by eliminating fluvial specialist species that would be expected to inhabit this type of river reach (i.e., a reach with an unmodified flow regime). Relative to largemouth bass (Micropterus salmoides) and spotted bass (M. punctulatus), we found that population characteristics (i.e., age, growth, catch rates, habitat use, diets) generally did not differ from those for fish from lentic areas within the Coosa River nor from other lotic populations.

High-resolution Numerical Simulation of Flow Through a Highly Sinuous River Reach

River dynamics involve complex, incompletely understood interactions among flow, sed- iment transport and channel form. The capacity to predict these interactions is essential for a variety of river management problems, including channel migration, width adjustment and habitat develop- ment. To address this need, high-resolution numerical models increasingly are being used by river engineers, fluvial geomorphologists and river biologists to explore the complexity of river dynamics and to predict fluvial behavior. This paper presents numerical simulations through a natural meader- ing river using two different models: a depth-averaged numerical code with secondary flow correction and a fully 3-D, state-of-the-art, Computational-Fluid-Dynamics (CFD) code. Models predictions are compared to high-quality 3-D velocity data collected in a highly sinuous reach of the Embarras River in Central Illinois, showing a successful simulation of the main flow features. Implications for sediment transport, planform development and habitat structure throughout the reach are analyzed, demonstrating the potential use of the models as a tool for river management.

Time-Delay Estimation of a Managed River Reach from Supervisory Data

The problem addressed in this article is the estimation of the time-delay between the inflow rate and the downstream water level of a managed river reach from data collected in imposed experimental conditions. The modelling of the managed river reach shows that the feedforward control performed by the operator "hides" the reach time-delay in the transfer function of the closed-loop system. Therefore, most of the classical time-delay estimation methods are inappropriate. A time-delay estimation approach devoted to managed rivers is proposed, in which a time-day description, composed of estimated inlpulse responses, allows to clearly observe the evolution of the time-delays over one year. In practice, this approach is particulary interesting since it is based on production data and hence does not disturb the daily management of the process by any experimental protocol. Moreover, the use of the suggested approach does not require any synthesis parameter.

A hydrologic network supporting spatially referenced regression modeling in the Chesapeake Bay Watershed.

The U.S. Geological Survey has developed a methodology for statistically relating nutrient sources and land-surface characteristics to nutrient loads of streams. The methodology is referred to as SPAtially Referenced Regressions On Watershed attributes (SPARROW), and relates measured stream nutrient loads to nutrient sources using nonlinear statistical regression models. A spatially detailed digital hydrologic network of stream reaches, stream-reach characteristics such as mean streamflow, water velocity, reach length, and travel time, and their associated watersheds supports the regression models. This network serves as the primary framework for spatially referencing potential nutrient source information such as atmospheric deposition, septic systems, point-sources, land use, land cover, and agricultural sources and land-surface characteristics such as land use, land cover, average-annual precipitation and temperature, slope, and soil permeability. In the Chesapeake Bay watershed that covers parts of Delaware, Maryland, Pennsylvania, New York, Virginia, West Virginia, and Washington D.C., SPARROW was used to generate models estimating loads of total nitrogen and total phosphorus representing 1987 and 1992 land-surface conditions. The 1987 models used a hydrologic network derived from an enhanced version of the U.S. Environmental Protection Agency's digital River Reach File, and course resolution Digital Elevation Models (DEMs). A new hydrologic network was created to support the 1992 models by generating stream reaches representing surface-water pathways defined by flow direction and flow accumulation algorithms from higher resolution DEMs. On a reach-by-reach basis, stream reach characteristics essential to the modeling were transferred to the newly generated pathways or reaches from the enhanced River Reach File used to support the 1987 models. To complete the new network, watersheds for each reach were generated using the direction of surface-water flow derived from the DEMs. This network improves upon existing digital stream data by increasing the level of spatial detail and providing consistency between the reach locations and topography. The hydrologic network also aids in illustrating the spatial patterns of predicted nutrient loads and sources contributed locally to each stream, and the percentages of nutrient load that reach Chesapeake Bay.

Contrasting geology in the Pocologan River and Long Reach areas: implications for the New River belt and correlations in southern New Brunswick and Maine

The Pocologan River and Long Reach areas are situated in the New River belt, which comprises the westernmost exposures of Neoproterozoic rocks in southern New Brunswick. Previous mapping in the southwestern part of the New River belt indicated that Neoproterozoic and Cambrian rocks in the Pocologan River area are different from coeval strata in the Caledonia belt (Avalon /one sensu stracto) in the Saint John area. Recent mapping in the Long Reach area has shown that there are significant lithological changes across the Robin Hood Lake fault, which bisects the New River belt into northeastern (Long Reach) and southwestern (Pocologan River) segments. Neoproterozoic and Cambrian rocks in the Long Reach area are directly comparable to those in the Caledonia belt, demonstrating that the New River belt is composite.
 
 Recent data have also shown that Early Cambrian volcanic activity in the Pocologan River area is broadly contemporaneous with epeirogenic events related to a major sequence boundary in the Avalonian cover sequence. This suggests that the northeastern and southwestern segments of the composite New River belt may have experienced a similar tectonic event, possibly as separate but adjacent continental fragments or as geographically isolated parts of one Gondwanan terrane. The lithological similarity of late Early to (?) Middle Cambrian quartzose sedimentary strata in the Pocologan River area to Middle Cambrian rocks in the St. Croix belt in Maine also supports the suggestion that the St. Croix belt is part of this composite terrane.
 
 RÉSUMÉ
 Les secteurs de la riviére Pocologan et de Long Reach sont situes dans la ceinture de New River, qui englobe les affleurements les plus à I'ouest des roches du Protérozoique supéricur du Sud du Nouveau-Brunswick. Des travaux de cartographic antérieurs dans Ie sud-ouest de la ceinture de New River ont révé;lé que les roches du Protérozoique supeérieur et du Cambrien du secteur de la riviére Pocologan constituaient des exemplaires uniques de stretcs contemporaines de la ceinture de Caledonia (zone d'Avalon au sens strict) dans la région de Saint-Jean. Des travaux de cartographic recents dans le secteur de Long Reach ont révélé des changements lithologiques marqués a travers la faille du lac Robin Hood, qui subdivise la ceinture de New River en deux segments : les segments nord-est (Long Reach) et sud-ouest (riviere Pocologan). Les roches du Protérozoique supérieur et du Cambrien du secteur de Long Reach sont directement comparable? à celles de la ceinture de Caledonia, ce qui démontre que la ceinture de New River constitue unc ceinture composite.
 
 Des donées récentes ont également rétvélé que I'activitié volcanique du Cambrien inférieur dans le secteur de la riviére Pocologan a en gros été contemporaine aux phénomenes épirogéniques apparentés à une Iimite de séquence importante dans la séquence de couverture avalonnienne. Cela laisse supposer que les segments nord-est et sud-ouest de la ceinture composite de New River pourraient avoir été soumis a un phénomene tectonique analogue, possiblement en tant que fragments continentaux distincts mais adjacents ou de parties géographiquement isolées d'un terrane du Gondwana. La similarity lithologique des strates seédimentaires quartzeuses de la fin du Cambrien précoce au Cambrien moyen (?) dans le secteur de la riviére Pocologan avec les roches du Cambrien moyen de la ceinture de St. Croix au Maine appuie par ailleurs l’hypothése que la ceinture de St. Croix fail partie de ce terrane composite.
 
 Traduit par la rédaction

Interregional comparisons of sediment microbial respiration in streams

SUMMARY 1. The rate of microbial respiration on fine-grained stream sediments was measured at 371 first to fourth-order streams in the Central Appalachian region (Maryland, Pennsylvania, Virginia, and West Virginia), Southern Rocky Mountains (Colorado), and California’s Central Valley in 1994 and 1995. 2. Study streams were randomly selected from the United States Environmental Protection Agency’s (USEPA) River Reach File (RF3) using the sample design developed by USEPA’s Environmental Monitoring and Assessment Program (EMAP). 3. Respiration rate ranged from 0 to 0.621 g O2 g ‐1 AFDM h ‐1 in Central Appalachian streams, 0‐0.254 g O2 g ‐1 AFDM h ‐1 in Rocky Mountain streams, and 0‐0.436 g O2 g ‐1 AFDM h ‐1 in Central Valley streams. 4. Respiration was significantly lower in Southern Rocky Mountain streams and in cold water streams (< 15 ∞C) of the Central Appalachians. 5. Within a defined index period, respiration was not significantly different between years, and was significantly correlated with stream temperature and chemistry (DOC, total N, total P, K, Cl, and alkalinity). 6. The uniformity of respiration estimates among the three study regions suggests that sediment microbial respiration may be collected at any number of scales above the sitelevel for reliable prediction of respiration patterns at larger spatial scales.

Comparison of mainstem spawning habitats for two populations of fall chinook salmon in the Columbia River basin

Extensive hydroelectric development in the Columbia River system has eliminated most mainstem riverine habitat available for spawning by fall chinook salmon (Oncorhynchus tshawytscha). The two remaining populations, Hanford Reach, Columbia River and Hells Canyon Reach, Snake River, are separated geographically and their status is markedly different. Annual escapements to Hanford Reach have averaged approximately 80 000 adults, while the Snake River run size has declined to <1500 adults over the past 10 years. We compared their spawning habitat characteristics over a range of measurement scales, as a means to identify strategies for rebuilding the weak Snake River population. Physical habitat characteristics of redds were similar for both study areas. Redd locations were correlated with channel characteristics, such as braiding and sinuosity. Several differences between the two spawning areas were identified at the watershed scale: the Hells Canyon Reach had a much steeper longitudinal gradient, was largely confined by bedrock, and had a more variable flow regime. These features are controlling variables that operate at the reach-scale to limit the availability and size of substrate and other conditions that influence egg deposition and incubation survival. Geomorphological characteristics of the two study sites are sufficiently different to indicate that the production potential of the Hells Canyon Reach population is markedly lower than that of the Hanford Reach population. Copyright © 2000 John Wiley & Sons, Ltd.

Spatially Restricted Surveys over Time for Aquatic Resources

Consideration of the natural characteristics of aquatic resources and available frame material has led to the development of new designs for surveying large-scale regions. This paper illustrates survey designs developed to meet the requirements for surveying various aquatic resources, including a finite, discrete population, such as lakes within one or more states; a continuous linear population within a bounded area, such as wadeable streams within one or more states; and a continuous two-dimensional population within a bounded area, such as coastal waters associated with one or more states. We present a unified approach that addresses the differences of the aquatic resources assuming the availability of frame material, such as Geographic Information System (GIS) coverages of the boundary for coastal waters, stream network, and lake locations from U.S. Environmental Protection Agency's River Reach File 3, derived from U.S. Geological Survey digital line graph data from 1:100,000 scale maps. The basic design methodology distributes the sample over the spatial extent of the resource domain, and a panel structure can be used to extend the sample through time. Key features for the approach are (1) utilizing survey theory for continuous populations within a bounded area, (2) explicit control of the spatial dispersion of the sample, (3) variable spatial density, (4) nested subsampling, and (5) incorporating panel structures for sampling over time.

Sediment microbial respiration in a synoptic survey of mid‐Atlantic region streams

1. The rate of microbial respiration on fine‐grained stream sediments was measured at 196 first‐ to third‐order sites in the mid‐Atlantic region of the United States.2. Sample collection took place between April and July in 1993, 1994 and 1995.3. Study streams were randomly selected from the United States Environmental Protection Agency’s (USEPA) River Reach File (RF3) using the sample design developed by USEPAs Environmental Monitoring and Assessment Programme (EMAP).4. Respiration rate ranged from 0 to 0.622 g O2 g–1 ash‐free dry mass (AFDM) h–1, and was significantly correlated with stream temperature, water chemistry and physical habitat.5. Respiration rate was significantly higher in streams from the Chesapeake drainage area compared to those from the Ohio drainage area, and in streams from the Northern Appalachian Plateau and Uplands and Central Appalachian Valleys ecoregions compared with streams from the Blue Ridge and Central Appalachian Plateau ecoregions.6. Respiration was not significantly different among stream orders or between years.

Evidence of Grass Carp (Ctenopharyngodon idella) Reproduction in the Illinois and Upper Mississippi Rivers

Abstract Grass carp (Ctenopharyngodon idella) is an exotic species which was imported into the United States in 1963 to control aquatic vegetation. Individuals escaped from ponds and subsequently spread into streams in the Mississippi River basin. We have been collecting grass carp in the Illinois River since 1990, and some of our associates have also collected grass carp in other portions of the upper Mississippi River system. The presence of juveniles (some less than 20 mm long) and adults (some diploid) in our collections leads us to believe that grass carp are reproducing in the Illinois River, and their larvae are finding suitable nursery areas in backwaters. Naturalized, reproducing grass carp populations probably exist as far north as 209 km into the Illinois River. Collections of juveniles by other researchers indicate reproduction and recruitment may also be occurring in upper Mississippi River Reaches 25, 26 and the Open River Reach below Lock and Dam 27.

WATER LEVEL FORCASTING METHOD SUITABLE TO RIVER REACHES ON LAKESHORE PLAIN

从洪水特性出发,提出了一种适合于滨湖平原河段的水位预报方法。经实例验证,证明方法是有效的。;The factor which influences floods of river reaches on lakeshore plain is very complicated and the stage-discharge relation varies greatly. It is very difficult to forcast the water level in this area-This paper proposes a water level forcasting method suitable to the river reaches on lakeshore plain, on the basis of the characteristics of the floods. It is comfirmed to be one reasonable method through the case study.

Mapping of Benthic Enrichment Patterns in Narragansett Bay, Rhode Island

A synoptic reconnaissance survey was performed over a five-day period in August 1988 to assess benthic habitat quality throughout Narragansett Bay, Rhode Island, using REMOTS® sediment-profile photography and analysis in combination with measurements of the levels ofClostridium perfringens spores (a fecal indicator) in sediments. Three main areas of degraded benthic habitat quality related to either excessive organic enrichment or physical disturbance were identified based solely on the REMOTS® analysis: the Providence River Reach, Greenwich Bay and its associated coves and harbors, and an area located along the southwest side of Prudence Island. Sediments at many stations in these areas exhibited shallow apparent redox-potential discontinuity (RPD) depths, high apparent oxygen demand, and low-order benthic successional stages. ElevatedClostridium perfringens spore counts in surface sediments were attributed to inputs from wastewater treatment facilities. The highest spore counts occurred at the head of the bay, where wastewater treatment discharges and associated combined sewer overflows are numerous. Using data from the REMOTS® analysis and the sediment inventory ofC. perfringens spores, a distinction was made between organic enrichment of the bottom from sewage, versus nonsewage enrichment or physical disturbance. The combination of techniques employed in this investigation could be used to design more efficient monitoring programs to assess eutrophication effects in estuaries and determine the effectiveness of regulatory or management initiatives to reduce organic overenrichment of benthic habitats.

Stochasticity in Stream Fish Communities: An Alternative Interpretation

Stochasticity in Stream Fish Communities: An Alternative Interpretation