Regulated Rivers-research & Management最新文献

{"title":"An investigation of marginal habitat and macrophyte community enhancement on the river Torne, UK.","authors":"S. Clarke, G. Wharton","doi":"10.1002/(SICI)1099-1646(200005/06)16:3<225::AID-RRR581>3.0.CO;2-N","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200005/06)16:3<225::AID-RRR581>3.0.CO;2-N","url":null,"abstract":"During floodbank raising work as part of a major capital flood defence scheme on the River Torne between 1985 and 1990, selected reaches of the main trapezoidal channel were enhanced. By winning spoil from the channel margins and from borrow pits in the floodplain, a more varied marginal zone was created which maximised the potential habitat for wetland plant communities and their associated fauna. Enhancement comprised bank re-profiling to create narrow wetland shelves (berms), shallow bays, channel margins of varying shape and depth and linear still ponds from the borrow pits. The 1990 planting programme comprised 11 macrophyte species and a total of 7740 individual plants. This paper reports on an initial study to evaluate the marginal habitat enhancements on the River Torne 5 years after completion of the project. Lack of pre-scheme data necessitated a space-time substitution; enhanced river margins were compared with neighbouring reaches that had undergone conventional floodbank repair and remained as trapezoidal channel sections planted with a standard, low maintenance seed mix. Marginal vegetation was surveyed and supported by measurements of the physical habitat at 10 enhanced and 10 conventionally-engineered reaches. The macrophyte surveys and the results from the cluster analysis and polar ordination indicate that enhanced and conventionally-engineered reaches are floristically distinct and that the enhanced reaches have a more varied macrophyte community. The results from the Mann–Whitney U-tests show that enhanced reaches have significantly higher values of wetland species diversity and equitability, percentage of wetland species, bank width and soil moisture and significantly lower bank angles. However, the correlation and linear regression analyses did not show any strong associations between the physical habitat and plant parameters. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130248747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement and quantification of a sedimentation budget for a reservoir with regular flushing","authors":"M. Jansson, Ú. Erlingsson","doi":"10.1002/(SICI)1099-1646(200005/06)16:3<279::AID-RRR586>3.0.CO;2-S","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200005/06)16:3<279::AID-RRR586>3.0.CO;2-S","url":null,"abstract":"This paper provides a case study of successful removal of reservoir sediment by empty flushing. The main aim of this study was to determine: (i) sediment inflow to the Cachi reservoir; (ii) the pattern and rate of deposition in the reservoir; (iii) the erosion within the reservoir during flushing; and (iv) sediment outflow at a downstream hydrological station during flushing. The results are integrated as a sediment budget for the reservoir. The drainage basin of the Cachi reservoir in Costa Rica is 785 km2. \u0000 \u0000 \u0000 \u0000The sediment budget for the period between two flushings indicates a sediment inflow to the reservoir of c. 930 000 tonnes and a net accumulation of c. 133 000 tonnes, or 14.3% of the sediment inflow. The sediment throughflow was also c. 133 000 tonnes up to the erosion phase of the flushing, and the outflow during flushing including bed load was 663 000 tonnes, i.e. 71.4% of the sediment inflow. Thus, the flushing of the reservoir was highly effective in releasing sediment. \u0000 \u0000 \u0000 \u0000The balance of the sediment budget makes it probable that the major components of the sediment budget are of the right order of magnitude. The main principle to obtain correct sediment loads by the rating-curve technique was to collect sediment data from a large number of storm events at equal time intervals during rising and falling stages. This was achieved by turbidimeter recordings. Because of the wide scatter of data, sediment rating curves were developed on mean sediment loads in discharge classes to avoid the bias of log regressions. \u0000 \u0000 \u0000 \u0000The trap efficiency and sediment throughflow were determined with Sundborg's physically based sedimentation model. The throughflow amounted to 20% of the suspended sediment inflow, which compares well with the empirical budget. The depositional pattern in the Cachi reservoir was surveyed with side-scan sonar, repeated echo-soundings, and by excavating pits in deposits when the reservoir was empty. Deposition occurred mainly in the old river channel, indicating that the major part of the sediment is transported by density currents. \u0000 \u0000 \u0000 \u0000The volume of eroded material in the reservoir during scour valve release was estimated by echo-soundings before and after the flushing. Dry bulk density of the reservoir deposits was determined by X-ray radiographic and densitometric analysis. The radiographic analyses indicated a dry bulk density of 0.4 g cm−3 of the loose material in the thalweg, and 0.7 g cm−3 of the whole deposition depth on the terraces. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"366 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124591172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying and alleviating low flows in regulated rivers: the case of the rivers Bulbourne and Gade, Hertfordshire, UK.","authors":"C. Agnew, N. Clifford, S. Haylett","doi":"10.1002/(SICI)1099-1646(200005/06)16:3<245::AID-RRR583>3.0.CO;2-F","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200005/06)16:3<245::AID-RRR583>3.0.CO;2-F","url":null,"abstract":"This paper examines evidence for the occurrence and causes of low flows, and strategies for their mitigation, in two regulated, chalk-fed streams. The rivers occupy adjacent catchments of similar topography, have long histories of water exploitation and land-use change, and are subject to conflicting demands of water resource development and increased pressure for environmental improvement. In one case, a strategy of low-flow mitigation based upon reduced groundwater abstraction has been proposed. Although flows are shown to be declining through time, and low flows are more common over the last decade, analysis of rainfall records and groundwater levels produce inconclusive evidence for the causes of low flows. Despite their natural similarities, the catchments are shown to have very different sensitivities to low flow. When concentrating upon quantity of low flow, the River Gade appears to be most compromised, but when consideration is taken of water quality, the Bulbourne is more severely affected. An examination of catchment changes over a longer time period provides the best rationale for these sensitivities and contrasts. The study illustrates the potential danger of starting with a solely climatic–hydrological perspective to low flows which then progresses to a hydrological ‘solution’. Consideration of catchment land-use history, and of the importance of water quality, suggest limited applicability of reduced abstraction in mitigating low-flow problems in these kinds of environments. The study reinforces calls for further studies of groundwater–surface water interaction as essential inputs to appropriate and sustainable water resource management strategies. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"330 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123125242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 12‐month sediment and nutrient budget in a floodplain reach of the River Adour, southwest France","authors":"R. Brunet, K. Astin","doi":"10.1002/(SICI)1099-1646(200005/06)16:3<267::AID-RRR584>3.0.CO;2-4","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200005/06)16:3<267::AID-RRR584>3.0.CO;2-4","url":null,"abstract":"The sediment and nutrient budget in the floodplain reach of the River Adour in southwest France has been examined over a 1-year period (1991-1992). Outputs of total suspended matter, dissolved inorganic nitrogen (i.e. nitrate + ammonium ions) and dissolved inorganic phosphorus (DIP) and particulate phosphorus (PP) have been compared with inputs. Alternating phases of mobilization and retention are observed for all the elements considered. Low water periods in summer allowed retention of both soluble material (24-26% for inorganic nitrogen) and suspended matter (9-19%). However, mobilization of PP associated with suspended matter transport during these periods. Elevated discharges associated with increased rainfall during the autumn period induced significant mobilization for all elements. In contrast, the winter flood event gave rise to a retention of particulate material (i.e. suspended matter and PP, 11% and 26%, respectively), but a loss of soluble materials (5% for inorganic nitrogen and 186% for DIP). The spring flood event produced retention for particulate materials (26%) while inducing losses of inorganic nitrogen (9%) and gains of DIP (7.4%). These results are related to riparian vegetation and the dynamics of nutrient cycling within the floodplain.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127532894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salmonid habitat modelling studies and their contribution to the development of an ecologically acceptable release policy for kielder reservoir, North-East England.","authors":"C. Gibbins, R. Acornley","doi":"10.1002/(SICI)1099-1646(200005/06)16:3<203::AID-RRR579>3.0.CO;2-8","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200005/06)16:3<203::AID-RRR579>3.0.CO;2-8","url":null,"abstract":"1. Kielder Reservoir regulates the Rivers North Tyne and Tyne. It provides a regular supply of water for downstream users, supports abstractions for a major water transfer scheme and provides hydroelectric power (HEP). Kielder's release regime typically alternates between a 1.3 m3 s−1 compensation flow and 10–15 m3 s−1 HEP releases of between 3 and 7 days in duration. Occasionally releases of up to 30 m3 s−1 are made for the purpose of encouraging fish runs, for recreational events or to help in water quality management. The impacts of this release regime on Atlantic salmon (Salmo salar) and brown trout (S. trutta) habitat at four sites on the North Tyne are assessed and alternative regimes, designed to minimize impacts, are presented. \u0000 \u0000 \u0000 \u00002. There is no evidence that the compensation flow results in extreme loss of instream habitat. A discharge of 1.3 m3 s−1 ensures that water is maintained over most of the channel area at sites representative of upper, middle and lower sections of the North Tyne. This discharge lies above breaks in slope of respective site discharge versus wetted area curves; thus, disproportionate increases in discharge would be needed to increase wetted area. Simulations using the Physical Habitat Simulation System (PHABSIM) suggest that the compensation flow provides between 50% and 90% of the maximum possible weighted usable area (WUA) for juvenile (0+) salmonids. \u0000 \u0000 \u0000 \u00003. During HEP releases, juvenile salmonid habitat (WUA) apparently falls to between 20 and 40% of site maxima. Newly emerged juvenile fish (March and April) are most affected by HEP releases because they are relatively small (25 mm in length) and water temperatures are relatively low at this time of year. During March and April, critical near-bed displacement velocities for newly emerged fish may be exceeded across large parts (80%) of sites up to 8 km downstream from Kielder Reservoir; fish would either be displaced downstream or forced to relocate to flow refuge areas. \u0000 \u0000 \u0000 \u00004. The availability of Atlantic salmon spawning habitat (WUA) at a key site is limited by the compensation flow; 1.3 m3 s−1 provides approximately one third of the habitat available at the optimum discharge (4 m3 s−1). At this site, a discharge of approximately 2 m3 s−1 is needed to ensure most of the bed is inundated by water. Regulation has reduced the duration of flows exceeding 2 m3 s−1 from 90 to 60% of the spawning season. \u0000 \u0000 \u0000 \u00005. Simulations suggest that when discharge drops from 30 m3 s−1 to the compensation flow, up to 60% of the optimum spawning habitat available at the former discharge may be left stranded (dry). This could potentially lead to egg or alevin mortality. \u0000 \u0000 \u0000 \u00006. PHABSIM simulations suggest that increasing the compensation flow to 4 m3 s−1 during the spawning period (November and December) is likely to increase the availability of suitable spawning habitat. Also, increasing the compensation flow to 2 m3 s−1 during the incubation period (January through ","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117095434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A GIS‐based approach to mapping probabilities of river bank erosion: regulated River Tummel, Scotland","authors":"S. Winterbottom, D. Gilvear","doi":"10.1002/(SICI)1099-1646(200003/04)16:2<127::AID-RRR573>3.0.CO;2-Q","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200003/04)16:2<127::AID-RRR573>3.0.CO;2-Q","url":null,"abstract":"This study explores the use of Geographic Information Systems (GIS) techniques for mapping river channel planform change and bank erosion probability. The method used is primarily based on an approach developed by Graf (Graf, W.L. 1984. ‘A probabilistic approach to the spatial assessment of river channel instability’, Water Resour. Res., 20(7), 953–962), which proposed that bank erosion probability could be determined for any given cell on a floodplain by taking into account (i) its distance laterally and in the upstream direction to the active river channel, and (ii) a value representing flood magnitudes for the given period. In this study, Graf's method is refined by using a GIS approach and by incorporating the influence of geomorphic variables, such as river bank morphology, sediment type and floodplain vegetation, on bank erosion rates. In addition, the technique is applied to a wandering gravel-bed river of roughly 80 m width, representing a different type and size of river to that used in Graf's study. Thus, the wider applicability of the technique is tested. In addition, the analysis here covers only a short time scale (1988–1994) compared with that used by Graf. The high temporal resolution of this study is enabled by the use of aerial photography and also by the substantial channel changes that occurred within this time period as a result of several high magnitude flood events. The results of the study indicate the usefulness and validity of the approach, particularly with regard to floodplain erosion hazard mapping and the assessment of the effects of altered flood regimes and land use. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124424144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term data assessment of chironomid taxa structure and function in the River Thames","authors":"L. Ruse, M. Davison","doi":"10.1002/(SICI)1099-1646(200003/04)16:2<113::AID-RRR572>3.0.CO;2-5","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200003/04)16:2<113::AID-RRR572>3.0.CO;2-5","url":null,"abstract":"Discharge of the River Thames is already regulated to prevent flooding and to satisfy demands for water. A flood alleviation channel is under construction, while a pumped-storage reservoir has been proposed to further regulate discharge for water supply. The aim of this investigation was to assess the suitability of available quantitative macroinvertebrate data for detecting significant change in biological structure and functioning, and substratum composition, following the implementation of these schemes. Pupal exuviae of Chironomidae (non-biting midges) were collected from eight surveys of the freshwater River Thames from 1977 until 1997. Multivariate and univariate statistics were used to investigate biological variation between surveys, independently of variation between sites. Over 48% of biological variation was explained by the available physical and chemical data. Temporal variation was almost independent of spatial variation. River discharge was the most important environmental variable correlated with chironomid taxa abundances between surveys, particularly in the lower Thames. High concentrations of un-ionized ammonia occurred during 1977, the effects of this were also greatest in the lower Thames. Indicator taxa have been identified which can be used as a simple monitoring tool to track the effects of varying flow and nitrogen flux between surveys. Proportions of fine sediment-dwelling chironomids, and their functional feeding types, have not significantly changed at sampling points immediately above or below the proposed reservoir or the imminent confluence with the flood alleviation channel over the 20-year survey period. These data provide the basis for detecting significant impacts by such schemes if or when they are completed. This knowledge would benefit any future plans to regulate or alleviate river flows. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124570278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gross channel changes along the Durance River, Southern France, over the last 100 years using cartographic data","authors":"R. Warner","doi":"10.1002/(SICI)1099-1646(200003/04)16:2<141::AID-RRR574>3.0.CO;2-2","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200003/04)16:2<141::AID-RRR574>3.0.CO;2-2","url":null,"abstract":"Gross channel changes for the Durance were determined using topographic maps from the 1890s and 1980s. Various width parameters were measured at 1 km intervals over 189 km from the Rhone junction at Avignon to La Saulce, some 31 km downstream of the dam at Serre Ponc¸on. During this period channel size has been considerably reduced. This can be attributed to four factors, two natural and two human induced. Firstly, there was a reduction in effective runoff at the end of the Little Ice Age (late 19th century). Secondly, runoff was further reduced with lower precipitation after about 1940. Thirdly, channel widths have been reduced by bank protection and by flood mitigation works. Finally, large-scale river regulation by EDF (Electricite de France), completed in the early 1960s, includes large dams to store alpine runoff, concrete canals to convey released water through some 20 power stations, and barrages to intercept tributary runoff and divert flows into the canals. In the lower Mediterranean part of the river, some of the diverted waters are discharged into irrigation and urban water canals (about 114 m3 s−1) and the rest into the Etang de Berre. Only about 1% of the mean discharge now reaches the Rhone. Discussion of available research provides insight into the four impacts, including additional comparative post-regulatory evidence from the Syndicat Mixte, a group concerned with environmental problems in the lower river. Evidence for channel change in lower parts of tributaries and for bed incision was found to be less conclusive. Such impacts may have been reduced by the interruptions of long-profile continuity by barrages and dams, and by lower discharges. Such discontinuities have adversely affected the ecology, low environmental flows and treated sewage dispersion. With some exceptions, environmental sustainability has not been a major issue because the Durance is such an important economic resource in terms of power, urban and irrigation waters, and building materials. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117311635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Passage facilities for Diadromous freshwater shrimps (Decapoda: Caridea) in the Bananier River, Guadeloupe, West Indies","authors":"É. Fièvet","doi":"10.1002/(SICI)1099-1646(200003/04)16:2<101::AID-RRR569>3.0.CO;2-T","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200003/04)16:2<101::AID-RRR569>3.0.CO;2-T","url":null,"abstract":"The relative selectivity of two fast-flowing concrete channels acting as passage facilities for shrimps was investigated at two low-head dams by comparing shrimps migrating through the channels to shrimps captured by experimental (trapping) passes offering splash zones. Complementary visual observations of shrimp behaviour were also carried out. At both dams (150 and 320 m above sea level (a.s.l.)), the upstream migration was mainly undertaken by small (subjuvenile) individuals but some larger ones, notably Atya innocous adults, were also captured. Strong water currents (1.5 m s−1) in the concrete channels compelled most shrimps to climb over the vertical walls but only the smallest individuals were able to do this. Thus, lower proportions of larger individuals were captured in the passage facilities than in the experimental passes. In the same way, the lightly built Macrobrachium spp. was found in lower proportions in the passage facilities than in the experimental passes. Furthermore, because of submerged orifices and whirling currents, the continuous-flow tanks which supplied the channels with water trapped numerous climbing shrimps. Hence, because they do not take biological criteria into account, the passage facilities investigated here were not only selective but also inefficient for shrimps. Finally, the benefits of such installations for shrimps are doubtful and simple waterfalls flowing over spillways would be at least as efficient, if not more so. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129830639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Minor local effects of a River Thames power station on the macroinvertebrate fauna","authors":"J. Wright, J. Winder, R. Gunn, J. Blackburn, K. Symes, R. Clarke","doi":"10.1002/(SICI)1099-1646(200003/04)16:2<159::AID-RRR575>3.0.CO;2-B","DOIUrl":"https://doi.org/10.1002/(SICI)1099-1646(200003/04)16:2<159::AID-RRR575>3.0.CO;2-B","url":null,"abstract":"In July 1996, a survey of the macroinvertebrate fauna of the River Thames was undertaken in the vicinity of Didcot A Power Station, which is located on the right (south) bank of the river. The aim was to determine whether short-range biological effects could be detected due to abstraction and discharge of cooling water. Sampling zones were selected upstream of the abstraction point (zone A), between the abstraction and discharge point (zone B), and below the discharge point (zone C). Five pond-net and five dredge sampling units were taken from each bank in each of zones A, B and C and analyses were undertaken at BMWP family level. A total of 46 BMWP families were captured during the survey. \u0000 \u0000 \u0000 \u0000Marginal pond-net samples from the left bank had a significantly higher mean number of BMWP taxa than those from the right bank. These differences are thought to be due to the greater diversity of macrophytes and substrata on the left bank. In addition, there were lower numbers of BMWP taxa on the right bank of zone C compared with zone B (but not zone A), probably due to poor quality habitat. \u0000 \u0000 \u0000 \u0000When the fauna from dredge samples in ‘control’ zone A was compared with zone B, there was no evidence on either bank of a deleterious impact on the fauna in zone B. Comparison of dredge samples from zone C with those from zones A and B, revealed no statistically significant differences in the number of BMWP taxa between zones C and A or between C and B on either bank. However, the first two dredge sampling units from the right bank of zone C, immediately downstream of the discharge point, had just five and 12 BMWP taxa, respectively, compared with a range of 17–28 taxa in all other dredge samples (on either bank of the three zones). These results correlated with a local change in dominant substratum to sand and associated fine particles, and suggest a very localized effect of the discharge on river-bed morphology and hence on the fauna of the right bank in zone C. Copyright © 2000 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"35 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133070922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}