bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of regulation on 0+ fish recruitment in the great ouse, a lowland river
Authors: Copp Gordon H. 
Published: February 2007

AbstractThe recruitment of 0+ fishes in the River Great Ouse, East Anglia (U.K.), was investigated using electrofishing by Point Abundance Sampling, in order to compare the distribution and extent of fish reproduction in the river and its annexes (side channels, backwaters, etc.) with similar but unregulated lowland rivers of Europe. In all, 44 sites were sampled during three weeks in August 1989. Correspondence Analysis of the Sites‐by‐Species matrix (44 × 17) in density (fishes per m2) revealed a slight but notable longitudinal zonation of fish reproduction, unusual for lowland rivers, with the limnophils Blicca bjoerkna (L.), Scardinus erythrophthalmus (L.) and Abramis brama (L.) limited to lentic downstream sites and the rheophil Barbus barbus (L.) restricted to a few upstream sites. Thus, compared with unregulated rivers of Europe, the River Great Ouse differs by: (1) the absence of pelagic spawners, e.g. Lota lota (L.), which were historically reported as abundant; (2) the reduced range and abundance of both rheophilic and limnophilic cyprinids, e.g. B. barbus (L.), Alburnus alburnus (L.) and Blicca bjoerkna (L.), Scardinus erythrophthalmus (L.), Abramis brama (L.), Tinca tinca (L.); and (3) the predominance of generalists throughout the system, Rutilus rutilus (L.) downstream and Phoxinus phoxinus (L.) with Gasterosteus aculeatus (L.) upstream, probably to the additional detriment of the localized specialists, both limnophilic and rheophilic.
Enhancement of benthic macroinvertebrates by minimum flow from a hydroelectric dam
Authors: Weisberg Stephen B. , Janicki Anthony J. , Gerritsen Jeroen , Wilson Harold T. 
Published: February 2007

AbstractThe biological consequences of instituting a summer minimum flow from the Conowingo Hydroelectric Dam were investigated by comparing invertebrate abundance in the Susquehanna River during 1980, when flow shutdowns were frequent, to that in 1982, when the minimum flow (142 m3 s−1) was maintained. The minimum flow was only maintained from April 15 to September 15, and additional investigations compared invertebrate abundance before and after the minimum flow was terminated in the fall of 1982 and 1983. There was a large difference in summer invertebrate density in the between‐year comparison, with almost a 100‐fold increase in the year when the minimum flow was maintained. Most of this difference was exhibited by two taxa, chironomids and net‐spinning trichopterans. These results were consistent with findings from the fall of 1982 and 1983, when cessation of the minimum flow in September led to declines of more than three orders of magnitude in both of these taxa. The rate of decline was faster in the shoal habitat (areas dewatered at low flow, but submerged when the minimum flow is released), suggesting that dewatering was the predominant mechanism of effect. Declines were also evident in the channel habitat (always submerged), suggesting that maintenance of current velocity is also an important beneficial component of the minimum flow.
Assessing options for stream regulation using hydrologic simulations and cumulative impact analysis: Flathead River Basin, U.S.A.
Authors: Jourdonnais J. H. , Stanford J. A. , Hauer F. R. , Hall C. A. S. 
Published: February 2007

AbstractThis study attempted to resolve regulation problems up‐ and downstream of Flathead Lake and on the lake proper. Members of a technical working group, representing eight water and wildlife management agencies, contributed 75 regulation scenarios they deemed necessary to conserve or enhance ecological (fish and wildlife) and societal (hydropower production, flood control, and recreation) resources for which they had management authority. The hydrology model simulated the effect of each scenario on system water balance; scenarios that were within the physical and legal constraints of the system were accepted for determination of cumulative impacts on resources. A multiattribute tradeoff analysis was used to assess cumulative impacts to key resources as a consequence of each regulation scenario (simulation) accepted for evaluation. Impacts were subjectively and independently quantified by each member of the working group following a point and importance weighting system agreed to a priori. Valuation of impacts was done on the basis of 36 technical studies of the effects of regulation on system resources. Impact valuations were summed to yield a variable referred to as weighted cumulative impact (WCI), where the highest, positive WCI indicated least cumulative impact on resources. Scenarios were then ranked in terms of WCI. When ecological resources only were evaluated, the preregulation Flathead Lake scenario generated the highest WCI. However, when all resources were considered, scenarios ranked very differently but a preferred alternative was identified by virtue of its highest WCI. This interactive process of hydrology simulation and computation of cumulative impacts mediated resource conflicts and served as an important tool in deriving water management recommendations in the Flathead River Basin. The process may be useful elsewhere.
Effect of decreased temperature on growth and smoltification of juvenile atlantic salmon (salmo salar) and brown trout (salmo trutta) in a norwegian regulated river
Authors: Saltveit Svein Jakob 
Published: February 2007

AbstractThe lowermost 20 km of the River Surna, northwestern Norway receives cool water during summer from a hypolimnetic release mountain reservoir. In this part of the river, yearlings of both Atlantic salmon and brown trout are significantly smaller compared with those in the upper section of the river, which is unaffected by the cold water release. The slower growth below the power station causes both Atlantic salmon and anadromous brown trout to smoltify one year later compared with fish in the upper section of the river. This leads to higher mortality and therefore lower production of both adult salmon and trout.
Macroinvertebrate responses along a complex regulated stream environmental gradient
Authors: Voelz Neal J. , Ward J. V. 
Published: February 2007

AbstractSamples were collected year‐round over a one‐year period at sites located downstream from a hypolimnetic‐release reservoir on the Blue River, Colorado, to examine macroinvertebrate responses along a complex environmental gradient induced by river regulation. Six sampling sites were established in riffles downstream of the dam using approximately a geometric progression starting at 0.25 km. Ordination techniques were used to elucidate macroinvertebrate distributional patterns along the complex environmental gradient. The detrended correspondence analysis (DCA) showed a sequential faunal gradient with the most rapid change occurring within the first 2.0 km below the impoundment. Detrended canonical correspondence analysis (DCCA) was used to relate faunal distributions to downstream changes in environmental variables. Downstream decreases in periphyton standing crop and minimum temperatures, and downstream increases in food resources and maximum temperatures, were identified as the major variables structuring faunal assemblages. The combined use of different gradient analysis techniques proved useful for identifying distinct macroinvertebrate distributional patterns and the environmental variables that may be responsible for these patterns.
The Rhine rift valley ground water—river interactions: Evolution of their susceptibility to pollution
Authors: Carbiener R. , Tremolieres M. 
Published: February 2007

AbstractThe exchange processes between the Rhine river and the alluvial aquifer were analysed in the upper part of the rift valley (upstream of Strasbourg). Hydraulic works, and the consequent suppression of flooding, along the Alsace Rhine floodplain greatly modified these processes. The transfer of persistent toxic micropollutants (organochlorine compounds, mercury), and non‐persistent pollutants (organophosphorous compounds: Sandoz spill) from the Rhine to the groundwater‐fed streams was exhibited by pollutant bioaccumulation in fish (particularly in the eel) and eutrophication of these streams near the canalized river.Comparison of the hydrological functioning of the two main river floodplains (the Rhine and its tributary, the Ill in the Alsace Rhine plain) shows two completely different exchange processes: in the case of the canalized Rhine, the groundwater is affected by direct transfer of pollutants through the channel bed. In the other case, that of the river Ill, where the floodplain is still widely flooded each year, the self‐purification of the floodwaters transferred to the groundwater is very effective: the soil‐root system of alluvial forest and meadow apparently having a high purification capacity.
Transferability of water entitlements in Australia
Authors: Pigram John J. , Musgrave Warren F. 
Published: February 2007

AbstractUntil recently, entitlements to water in Australia have been tied to a specific area of land. Several State water management agencies have now adopted more flexible arrangements for the transfer of water rights between users on regulated streams. The case for freer transfers is linked to the perceived need for greater efficiency in water use. Transferability also has potential in facilitating the movement of water between different sectors of the water industry and in achieving more rational and environmentally acceptable use of resources. Justification for breaking the nexus between water rights and land needs to be assessed against a number of physical, social, economic, and environmental issues some of which have only become apparent with accelerated resource development, and expansion and concentration of Australia's urban‐industrial base. These trends are reflected in competing claims on water resources to supply the increasing demand from city‐based populations; to maintain the viability of industrial systems; to sustain more intensive high technology forms of irrigation agriculture; and to satisfy the water needs of often remote mining and tourist developments. No longer can such claims easily be met by harnessing further water resources. Transfers of water rights, on a much larger scale, within and between water‐using regions and sectors, and across State borders, are likely to be an important element in Australia's water industry in coming decades.
Benthic macroinvertebrate communities in nonregulated and regulated waters of the clearwater river, Idaho, U.S.A.
Authors: Munn Mark D. , Brusven Merlyn A. 
Published: February 2007

AbstractBenthic macroinvertebrates were examined over a two‐year period in nonregulated, regulated, and semiregulated reaches of the Clearwater River in northern Idaho. Macroinvertebrate communities in the nonregulated reach above Dworshak Reservoir were taxonomically diverse at all stations. In contrast, the macroinvertebrate community in the regulated reach of the North Fork of the Clearwater River (NFCR) was severely altered with high macroinvertebrate abundance and low taxa richness (2 to 8 taxa). Orthoclad chironomids dominated this reach composing between 68 and 99 per cent of total benthic invertebrate numbers. The mayfly Ephemerella infrequens was the only other macroinvertebrate to be abundant in the regulated reach. The major factors contributing to the simplified macroinvertebrate community are reduced habitat diversity, fluctuating water levels, altered thermal regime, and possibly an altered food supply. The effects of the dam were mitigated in the semiregulated Mainstem of the Clearwater River (MSCR) due to the merger of a nonregulated fork entering 2.5 km downstream from the dam. The macroinvertebrate community in the semiregulated MSCR was more complex than the regulated reach with a community structure resembling that found above the reservoir.
Complex response of a sand‐bed stream to upstream impoundment
Authors: Sherrard J. J. , Erskine Wayne D. 
Published: February 2007

AbstractMangrove Creek Dam, the eighth highest dam in NSW, Australia has induced a complex response of the downstream, sand‐bed channel. Since dam closure on 1 October 1981, mean daily flows and the peak instantaneous discharge of floods have been reduced greatly (up to 94 per cent) and nearly 100 per cent of the incoming sediment load has been trapped behind the Dam. The magnitude of the hydrologic effects decreases with distance downstream. River response varies in direct proportion to the magnitude of the altered hydrologic regime and includes alternating but localized bed aggradation and degradation as well as channel contraction. Contraction has occurred by a combination of in‐channel bench construction, the formation and bank attachment of longitudinal bars and bank deposition. Leptospermum polygalifolium has rapidly colonized these in‐channel deposits and will result in the stabilization of benches. Armouring has not been a significant feedback process to date because of the limited degradation and low gravel supply. It is postulated that the above trends will continue, thus converting the former large, straight, active sand‐bed channel into a small, sinuous, well‐ vegetated sand‐bed stream.
Turbidity control and fisheries enhancement in a bottomland hardwood backwater system in Louisiana (U.S.A.)
Authors: Ewing Michael S. 
Published: February 2007

AbstractIn response to a noticeable decline in recreational fishing in the formerly productive Larto—Saline backwater complex of east central Louisiana, a study was begun to identify causative factors for the decline and to determine effective methods to remedy the problem. To this end, water quality and fisheries surveys were conducted in the system for the study period 1 July, 1981 to 30 June, 1989.Data collected during the early years of the study indicated chronically high turbidity (> 100 FTU) to be the major factor limiting game fish production. The high turbidity can be related to man‐made alterations of natural flood patterns that had changed the major source of backwater flooding from Black River to the highly turbid Red River.In September, 1986, a construction project was undertaken to restore flood patterns to approximate natural conditions. Sampling subsequent to this construction has shown a significant decrease in turbidity and an increase in game fish production.
Development of water level regulation strategies for fish and wildlife, upper Mississippi river system
Authors: Lubinski K. S. , Carmody G. , Wilcox D. , Drazkowski B. 
Published: February 2007

AbstractWater level regulation has been proposed as a tool for maintaining or enhancing fish and wildlife resources in navigation pools and associated flood plains of the Upper Mississippi River System. Research related to the development of water level management plans is being conducted under the Long Term Resource Monitoring Program. Research strategies include investigations of cause and effect relationships, spatial and temporal patterns of resource components, and alternative problem solutions. The principal hypothesis being tested states that water level fluctuations resulting from navigation dam operation create less than optimal conditions for the reproduction and growth of target aquatic macrophyte and fish species. Representative navigation pools have been selected to describe hydrologic, engineering, and legal constraints within which fish and wildlife objectives can be established. Spatial analyses are underway to predict the magnitude and location of habitat changes that will result from controlled changes in water elevation.
Flume study of the hydraulic effects of large woody debris in lowland rivers
Authors: Young W. J. 
Published: February 2007

AbstractAs a part of a study investigating the hydraulic effects of large woody debris (LWD) in lowland rivers, a series of small‐scale experiments were conducted in a rectangular glass‐walled recirculating flume. These experiments were undertaken to determine the order of magnitude of the increase in flood levels caused by LWD at different positions within a channel cross‐section. Position variables that were considered in these experiments were height above bed, angle to flow direction, and separation distance in the direction of flow. This study was undertaken to quantify the hydraulic benefits (primarily reduced flood levels) gained by the removal of LWD from lowland rivers, which is a common practice in several countries. From an integrated river management perspective it is necessary to weigh any hydraulic benefits of LWD removal up against the environmental costs of loss of faunal habitat, and possible geomorphic instability.The results of these experiments indicate that the levels of LWD commonly occurring in the lowland rivers of southeastern Australia seldom cause any significant effect on flood levels. However, where LWD occur at channel constrictions, or where unusually high densities of LWD are present, the effect on flood levels will be significant.
Recovery of aquatic macroinvertebrate assemblages downstream of the Canning Dam, Western Australia
Authors: Storey A. W. , Edward D. H. , Gazey P. 
Published: February 2007

AbstractMacroinvertebrate assemblages downstream from the Canning Dam, on the Canning River, Western Australia, were sampled to assess the impact of long‐term impoundment and the role of a major tributary in community recovery.Kick samples and associated physical measurements were taken from riffle zones in three reaches in March and July 1989. The lower reach was located immediately downstream of the confluence with Stinton Creek, the first major tributary below the dam, with the middle and upper reaches positioned between the tributary and the dam.Reduced concentrations of dissolved oxygen in the upper and middle reaches in March, compared to the lower reach were attributed to significantly higher levels of organics, high summer water temperatures, and a proposed increase in microbial activity. The build‐up of organics was probably related to reduced flushing, as a result of impoundment. Stinton Creek increased the discharge of the Canning River below the confluence, particularly in winter, which presumably prevented the build‐up of organics in the lower reach.Significant differences in the aquatic macroinvertebrate fauna between reaches were detected. A total of 68 taxa was recorded from the lower reach, 88 per cent of which were also present in the middle and upper reaches. However, the middle and upper reaches contained a greater number of taxa (112 and 90 respectively), approximately 50 per cent of which were not recorded from the lower reach. The additional taxa were more typical of lowland rivers or lentic (standing water) systems, suggesting that physical conditions in the middle and upper reaches were more like a lowland river than an upland stream.More collectors and shredders occurred in the upper and middle reaches, associated with the accumulation of particulate organic matter. Ordination and classification procedures based on macroinvertebrate assemblages clearly separated samples from the upper and middle reaches from the lower reach. There was also a distinct seasonal separation.These observations support a hypothesis that while the reduced flow below Canning Dam had an impact on the macroinvertebrate fauna, confluence with a major tributary (Stinton Creek) allowed recovery of the macroinvertebrate community, through the tributary acting as a source of increased discharge. The implications for the management of impounded rivers in southwestern Australia are discussed.
Cross‐channel distribution patterns of zoobenthos in a regulated reach of the tennessee river
Authors: Haag Kim H. , Thorp James H. 
Published: February 2007

AbstractThe importance of substrate type and water depth was investigated in a regulated reach of a large, navigable river in the U.S.A. Benthic grab samples were collected in June and August, 1989, along two shore‐to‐shore transects in the lower Tennessee River, approximately 1.5 km downstream from Kentucky Lock and Dam. Diversity, averaged over all samples, was not significantly different from June to August. River depth of our samples, which ranged from 3.1 m to 6.5 m, significantly influenced macroinvertebrate density but had no detectable effect on the total number of taxa collected. Densities of flatworms, Asiatic clams, snails, isopods, and mayflies increased significantly with increasing depth, whereas the abundance of native mussels (Unionidae) and caddisflies decreased with depth. Substrate type (sand through cobble) influenced both the total number of taxa and the total number of organisms collected. Sample areas dominated by cobble contained significantly fewer individuals than areas composed predominantly of gravel substrate. Asiatic clams, the single most abundant species collected, were consistently more numerous on intermediate substrate sizes. In contrast, densities of native mussels, snails, and mayflies were not correlated with bottom type. Sample areas included relatively little mud and sand, resulting in relatively low numbers of oligochaetes and midges in our collections.
Development and habitat selection of chironomid communities
Authors: Grzybkowska Maria 
Published: February 2007

AbstractThe macrobenthos (especially Chironomidae) along channel margins has been compared for two 5th‐order rivers, the River Grabia, which has not changed its morphology for many years, and the River Widawka, which experienced an increase of channel width (by over 5 m) about eight years before the present study due to human impact. Also, the effect of frequent short‐term high water levels on the macrobenthos near the bank was investigated in the 7th order section of the Warta River downstream of a dam.The macrobenthos distribution was found to be similar in the ‘impacted’ Warta and Widawka Rivers, with the highest abundance near the bank, decreasing towards the mid‐channel. In the marginal zone of the Widawka River, abundant detritivorous invertebrates having low oxygen tolerance (mainly Prodiamesinae and Chironomini) were observed. The percentage of Chironomini in this zone of the Warta River was even higher than that in the Widawka River. A different pattern was observed in the ‘natural’ Grabia River—the lowest species number and density were at the banks: Orthocladiinae dominated especially in the mid‐river.A high abundance fluctuation of one of two dominant species in the margin of the Warta River—Glyptotendipes gripekoveni K. is remarkable. The larvae temporarily reached high densities on snags, which were periodically exposed and submerged by water, although over a year their density was lower (399 ind m−2) than that of those inhabiting the bottom (543 ind m−2).
Macrozoobenthos of floodplain waters of the rivers rhine and meuse in the Netherlands: A structural and functional analysis in relation to hydrology
Authors: Van Brink F. W. B. Den , Van Velde G. Der 
Published: February 2007

AbstractThe river systems of the Rhine and Meuse include a large number of floodplain waters showing differences in hydrology and geomorphology. A classification of 100 water bodies based on their macroinvertebrate communities has been worked out as a tool for ecological management. Analyses were performed on structural (species composition) and functional (trophic relations) aspects of macrozoobenthos in relation to hydrological, vegetational, and physicochemical parameters. Based on the classification of macroinvertebrate communities, three major groups of water bodies can be distinguished, which are related to the frequency of inundation. The flood frequency constitutes the major environmental gradient which structures the zoobenthos communities in the Dutch floodplain waters. Faunal composition is mediated by substrate availability, water chemistry, and the availability of nutritional resources. This typology serves as a basis for the prediction of the impact of hydrology changes on the macrozoobenthic communities of floodplain waters of highly eutrophic and polluted rivers.