Regulated Rivers-research & Management最新文献

{"title":"The impact of river regulation and climate change on the barred estuary of the Oued Massa, southern Morocco","authors":"H. Fox, R. Wilby, H. Moore","doi":"10.1002/RRR.613","DOIUrl":"https://doi.org/10.1002/RRR.613","url":null,"abstract":"The estuary of the Oued Massa, southern Morocco, has experienced alternating phases of tidal and lagoon conditions. Using field surveys, aerial photographs and rainfall–runoff records the dominant processes and recent evolution of the estuary are described. These data suggest that the character of the estuary has changed since the upstream impoundment of the river by the Youssef Ben Tachfine reservoir. The frequency of low-flows has been significantly increased by river regulation, as has the mean interval between flood events. Using reconstructed flow series it is speculated that lagoon conditions have become more common in the post-impoundment era than at any time since the 1920s. Although increases in winter precipitation projected by the global climate model HadCM2 for 2030–2049 imply a higher frequency of flood flows entering the reservoir in the future, the magnitude and frequency of such inflows are still within historic variability. Nonetheless, higher inflows may produce more frequent spills with concomitant bar breaching and termination of lagoon phases. Despite this, it is argued that the presence of the dam is ultimately of greater consequence to the functioning of the estuary–lagoon system than future precipitation changes over the region. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115474021","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":"Ecological effects of flow regulation on macroinvertebrate and periphytic diatom assemblages in the Hawkesbury–Nepean River, Australia","authors":"I. Growns, J. Growns","doi":"10.1002/RRR.622","DOIUrl":"https://doi.org/10.1002/RRR.622","url":null,"abstract":"The effects of flow regulation on macroinvertebrates and periphytic diatoms were examined in the Hawkesbury–Nepean River system in Australia. Regulated sites below eight dams or weirs were compared with unregulated sites above the impoundments and sites on two nearby unregulated streams. The management of the water supply during the study created two types of flow regulation, sites with water supply releases and sites with comparatively small or no releases. The macroinvertebrate communities in three habitats and periphytic diatoms below the storages and weirs differed from the biota at unregulated sites above the weirs and on unregulated systems. The number of macroinvertebrate taxa in riffle and pool-rock assemblages was significantly lower at regulated sites when compared with unregulated sites and the number of stream edge macroinvertebrate and diatom taxa was unaffected by regulation. Riffle and pool-rock macroinvertebrate assemblages differed between the two types of regulation. However, periphytic diatom and edge habitat macroinvertebrate assemblages did not differ between the two types of flow regulation. Examination of environmental variables associated with the change in the biota suggested that the principal effect of the management of the water supply system in the Hawkesbury–Nepean River was changed hydrology rather than altered water quality. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121031979","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":"Wetlands (third edition) by W.J. Mitsch and J.G. Gosselink. John Wiley & Sons, New York, 2000. No. of pages: 920. Price: £60.95. ISBN 0 471 29232 X.","authors":"C. Bradley","doi":"10.1002/RRR.637","DOIUrl":"https://doi.org/10.1002/RRR.637","url":null,"abstract":"","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126940308","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 the natural flow regime and the relationship with riparian vegetation for two contrasting western Australian rivers","authors":"N. Pettit, R. Froend, P. Davies","doi":"10.1002/RRR.624","DOIUrl":"https://doi.org/10.1002/RRR.624","url":null,"abstract":"The natural flow regime and the relationship between flows and riparian vegetation are described for sites on both the Blackwood River in south-western Australia and the Ord River in north-western Australia. Analysis of long-term flow data showed the historic mean monthly river discharge for the Blackwood River is strongly seasonal and highly predictable with generally low variability each month. The Ord River showed a strong seasonality of flows with about 92% of the (total) yearly flow occurring between December and March. Flow variability was very high (e.g. coefficient of variation >100% for all months) but highly predictable, with this mostly attributed to low but constant dry-season flows. Water depth, duration of flood events and the number of flood events per year show a significant correlation with aspects of the riparian vegetation within experimental vegetation plots. Results highlight the strong relationship between floristics, life form structure and population dynamics with stream hydrology. On the Blackwood River, species richness and cover of shrubs reduced with increased duration and frequency of flooding, while cover of exotic species and annual herbs increased with increased flooding. Germination of tree seedlings was not influenced by flood regime but size class of tree species increased with flooding frequency. On the Ord River, species richness was not influenced by flooding regime. However, cover of perennial grasses increased with flooding frequency whilst cover of shrubs decreased. There was no relationship between flooding and seedling establishment whilst tree size class decreased with increased flooding. The methods described here can be used to compare the response of different components of the riparian vegetation to different fluvial regimes (e.g. because of impoundment and abstraction). This technique can be expanded for the management of riparian zones and planning rehabilitation programmes. It may also be useful for improving the ecological knowledge base for setting environmental flows in regulated systems. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134588818","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":"Hindrances to upstream migration of Atlantic salmon (Salmo salar) in a Northern Swedish river caused by a hydroelectric power-station","authors":"P. Rivinoja, S. McKinnell, H. Lundqvist","doi":"10.1002/RRR.607","DOIUrl":"https://doi.org/10.1002/RRR.607","url":null,"abstract":"Many Baltic salmon rivers have lost their natural juvenile production due to human activities blocking or reducing access to their spawning grounds, e.g. damming, power generation, partial hinders, etc. One such hindrance is a hydroelectric complex located in the lower reaches of River Umealven in northern Sweden. Water from the forbay created by the dam Norrfors is directed to the Stornorrfors power-station. At times, 100% of the river water is directed to the power-station. Water from the power-station then flows via a tunnel and outlet channel to the river. From the point of the tunnel's discharge into the river, the old river bed acts as a bypass channel directing migrating adult fish to a fish ladder located at the base of the dam. \u0000 \u0000 \u0000 \u0000In this study, the effect that an additional turbine, that was installed at the power-station in 1986, had on fish passage run-time was examined. Changes in run-time were compared for two periods 1974–1985 and 1986–1995. In 1997, 55 wild and 25 hatchery salmon were captured in the Umealven estuary, radio tagged with uniquely coded tags, and tracked upstream. Both manual and automatic loggers were used to locate fish daily. The main findings show that only 26% of the wild salmon and none of the hatchery salmon found the fish ladder. It is suggested that the salmon followed the main water discharge from the power-station outlet and are thus directed away from the entrance to the bypass channel leading to the fish ladder. Salmon respond by moving upstream or downstream depending on the current flow regimes. The bypass channel consists of partial hinders that may explain why it takes on average 52 days for the salmon to migrate 32 km from the estuary to the fish ladder. Adding a fourth turbine at the power-station did not appear to have changed the timing of the migration or the seasonal distribution of the migrating wild salmon through the fish ladder. There was no significant effect of the fourth turbine on the duration of the middle 50% of the run in any weight-class for wild salmon. Daily turbine discharges or ambient water temperature and daily counts of wild salmon at the fish ladder were not related. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128765674","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":"Spatial variability of biotic and abiotic factors of the aquatic habitat in French Guiana","authors":"F. L. Tejerina-Garro, B. Mérona","doi":"10.1002/RRR.619","DOIUrl":"https://doi.org/10.1002/RRR.619","url":null,"abstract":"Research on tropical fish ecology in South America is focused mainly on the effect of environmental variables on aquatic organisms. Physical, chemical and biological characteristics of water measured at a local scale (local variables) are used, although geomorphological and hydrological factors measured at a regional scale (regional variables), as well as temporal and spatial heterogeneity, can also be considered. However, the use of this multi-scale approach increases the perceived complexity, heterogeneity and variability of rivers. Thus, it is important to determine the magnitude of habitat variability and those parameters having the greatest influence on it. In this study, 28 stations distributed on 16 different rivers in French Guiana were sampled during high water at a meso spatial scale. Physical features of the rivers were sampled along an 800-m stretch, where nine transversal transects were established on the main channel. At each river, 17 local and six regional variables were measured. Local variables relating to the physical characteristics of the channel bank and main channel and regional variables characterizing the whole basin and the position of the station in the basin were qualitatively and quantitatively described. All variables were submitted to multivariate analysis in order to determine their relative contribution to total variance. Two quantitative regional variables (drainage area upstream from station and river drainage basin), five quantitative local variables (channel width, water temperature, channel depth, Secchi transparency and conductivity) and one qualitative local variable (channel substrate) were shown to differentiate the 16 rivers sampled. This result shows the poor contribution of qualitative variables compared with quantitative ones. Gradual change in qualitative variables is probably responsible for this poor contribution to the total variance; thus, the use of such variables is not possible for spatial habitat differentiation in this study. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126043341","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":"Effects of pool formation and flash flooding on relative abundance of young-of-year flannelmouth suckers in the Paria River, Arizona","authors":"M. Thieme, C. Mcivor, M. Brouder, T. Hoffnagle","doi":"10.1002/RRR.618","DOIUrl":"https://doi.org/10.1002/RRR.618","url":null,"abstract":"Flannelmouth sucker, Catostomus latipinnis, a fish endemic to the Colorado River basin in the western United States, appears to experience poor recruitment to adult size in the Colorado River, downstream of Glen Canyon Dam. Lack or impermanence of rearing areas for young-of-year (YOY) fish is hypothesized to be the problem. Knowing the importance of tributary mouths as rearing areas in other river systems, we studied use of the mouth of the Paria River, a tributary of the Colorado River, by YOY flannelmouth suckers, and the availability of rearing area in the mouth at different flow levels in the Colorado River in 1996 and 1997. We also examined the relationship between flash floods in the Paria River and catch-per-unit-effort (CPUE) of YOY in the Paria River between 1991 and 1996. \u0000 \u0000 \u0000 \u0000Maximum mean daily discharge in the Paria River was inversely correlated with CPUE of YOY flannelmouth suckers (Spearman Rho=−0.9856, p=0.0003) during their critical rearing period (15 March–30 June). Thus, it appears that YOY flannelmouth suckers rear longer in the Paria River in years when flash flooding is minimal. \u0000 \u0000 \u0000 \u0000Recruitment of YOY flannelmouth suckers at the Paria River may also be improved by enhancing pool formation during spring and summer rearing seasons. YOY flannelmouth sucker was captured in a pool created by high Colorado River flows (≥336 m3/s) that inundated the mouth of the Paria River during spring and summer, 1996. In 1997, high flows (about 550–750 m3/s) in the Colorado River during winter and spring initially inundated the Paria River and formed a pool in the mouth. However, these high flows eventually caused 0.5–1.0 m of suspended sediment from the incoming Paria River to deposit in the mouth. Thus, despite higher flows than 1996, the slackwater area formed only occasionally in 1997. Differences in pool formation between 1996 and 1997 demonstrate that pool formation cannot be inferred solely from Colorado River flows. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"130 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131213603","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":"Ecological rehabilitation of the Dutch part of the River Rhine with special attention to the fish","authors":"A. Raat","doi":"10.1002/RRR.608","DOIUrl":"https://doi.org/10.1002/RRR.608","url":null,"abstract":"The River Rhine has suffered severely from pollution and stream regulation over the last two centuries. Industrial effluents and municipal wastewater have imposed pollutant loads, and major engineering works for drainage and navigation have changed the ecological condition of the river. Only during the last three decades has the rehabilitation of the river system been a topic of concern. \u0000 \u0000 \u0000 \u0000The present fish fauna is dominated by eurytopic cyprinids. Rheophilous species have declined in numbers, and anadromous fish have become scarce or extinct. \u0000 \u0000 \u0000 \u0000Various forms of ecological rehabilitation in the Dutch Rhine are identified: floodplain development; optimization of migration routes with emphasis on the entrance of migrating species from the sea into the river; and restoration of spawning and nursery areas. \u0000 \u0000 \u0000 \u0000Ecological restoration of the Rhine is an international effort. The present socio-economic functions of the river pose serious constraints on the feasibility of ecological targets. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134147543","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":"Changes in backwater plant communities from 1975 to 1995 in Navigation Pool 8, Upper Mississippi River","authors":"Robin W. Tyser, S. Rogers, T. W. Owens, Larry R. Robinson","doi":"10.1002/RRR.609","DOIUrl":"https://doi.org/10.1002/RRR.609","url":null,"abstract":"Water elevation in the Upper Mississippi River (UMR) is highly regulated by an extensive system of locks and dams. Completion of this system in the 1930s created productive, biologically diverse backwater habitats. The status of plant communities in these backwater areas may now be threatened by several factors, including sediment accumulation, recreational use, and navigation traffic. Aerial photography, taken in 1975 and from 1991 to 1995, was used to describe vegetation changes occurring in four UMR backwater areas of Navigation Pool 8. The objectives were to determine (1) if changes occurring in these areas are consistent with hydrarch succession, (2) if the diversity of their plant communities has declined since 1975, and (3) how a large flood event that occurred in 1993 affected the composition and diversity of plant communities in these areas. Three general cover classes were recognized, representing an aquatic to terrestrial gradient. Coverages of specific vegetation types were estimated and evaluated using two indices of community diversity (vegetation richness and the Shannon diversity index). Though some vegetation changes were consistent with expected successional patterns (e.g. increased terrestrialization), other changes were not (e.g. loss of marsh vegetation). Diversity indices and coverages of most aquatic macrophytes declined from 1975 to 1991/1992 but then increased following the 1993 flood. The results suggest that disturbance–diversity concepts, including the flood pulse model, are applicable to the vegetation dynamics of these systems. Published in 2001 by John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115056227","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":"Propagules in dry wetland sediments as indicators of ecological health : Effects of salinity","authors":"R. Skinner, F. Sheldon, K. Walker","doi":"10.1002/RRR.616","DOIUrl":"https://doi.org/10.1002/RRR.616","url":null,"abstract":"Indicators of ecological health are problematic for wetlands in dry regions because distinctive communities are associated with dry and wet phases of indefinite duration. The propagule bank, including the resting stages of aquatic animals and plants, maintains the community's capacity to recover from drought or disturbance. This paper records observations of invertebrates, protists and algae emerging in laboratory microcosms following the inundation of dry sediments from two temporary lakes on the River Murray floodplain in South Australia. A simple experiment carried out on the sediment from one lake showed that increased salinity was associated with lower diversity (richness) but higher abundance of emergent organisms. The effect on diversity was evident at salinities above 11–17 mS cm−1, and the effect on abundances was evident above 6–11 mS cm−1 (salinity here is indicated by electrical conductivity at 25°C). These data suggest that propagule banks may be useful as complementary indicators of wetland health. Copyright © 2001 John Wiley & Sons, Ltd.","PeriodicalId":306887,"journal":{"name":"Regulated Rivers-research & Management","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126618625","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}