John T. Kemper, Richard Knox, Muhammad Raffae, Evan Schulz, Ryan Bailey, Ryan R. Morrison, Ellen Wohl
Catchment‐scale sediment storage is conceptualized as increasing in magnitude downstream, although reach‐scale controls may override this trend. We use empirical data from a literature review and two numerical models to quantitatively estimate sediment storage across the Colorado River Basin, USA. We use assumed alluvial thickness with floodplains delineated in the GFPLAIN model from 30 m digital elevation models. We use the SWAT+ model based on model‐estimated (i) groundwater storage and (ii) sediment storage. Existing studies indicate that sediment stored in floodplains and on low terraces is ~0.3–6 m thick. A first‐order approximation of volumetric storage capacity for natural floodplains is ~105 m3 per km. Sediment storage volumes of floodplains are ~108–1011 m3 over river lengths of 101–103 m. For the modeling estimates, we evaluated sediment storage by stream order and by elevation band within the Upper and Lower Colorado River Basins. Comparisons among the outputs cause us to place more confidence in the GFPLAIN and SWAT+ aquifer volume estimates. Each method includes substantial uncertainty and constitutes a first‐order approximation. Results suggest using 21 and 130 billion cubic meters as approximate lower and upper bounds for total sediment storage in the Upper Basin and 314 and 482 billion cubic meters as approximate lower and upper bounds for the Lower Basin. The largest proportion of sediment is stored in the montane and steppe zones in the Upper Basin and in the Sonoran zone in the Lower Basin.
{"title":"Estimating catchment‐scale sediment storage in a large River Basin, Colorado River, USA","authors":"John T. Kemper, Richard Knox, Muhammad Raffae, Evan Schulz, Ryan Bailey, Ryan R. Morrison, Ellen Wohl","doi":"10.1002/rra.4300","DOIUrl":"https://doi.org/10.1002/rra.4300","url":null,"abstract":"Catchment‐scale sediment storage is conceptualized as increasing in magnitude downstream, although reach‐scale controls may override this trend. We use empirical data from a literature review and two numerical models to quantitatively estimate sediment storage across the Colorado River Basin, USA. We use assumed alluvial thickness with floodplains delineated in the GFPLAIN model from 30 m digital elevation models. We use the SWAT+ model based on model‐estimated (i) groundwater storage and (ii) sediment storage. Existing studies indicate that sediment stored in floodplains and on low terraces is ~0.3–6 m thick. A first‐order approximation of volumetric storage capacity for natural floodplains is ~10<jats:sup>5</jats:sup> m<jats:sup>3</jats:sup> per km. Sediment storage volumes of floodplains are ~10<jats:sup>8</jats:sup>–10<jats:sup>11</jats:sup> m<jats:sup>3</jats:sup> over river lengths of 10<jats:sup>1</jats:sup>–10<jats:sup>3</jats:sup> m. For the modeling estimates, we evaluated sediment storage by stream order and by elevation band within the Upper and Lower Colorado River Basins. Comparisons among the outputs cause us to place more confidence in the GFPLAIN and SWAT+ aquifer volume estimates. Each method includes substantial uncertainty and constitutes a first‐order approximation. Results suggest using 21 and 130 billion cubic meters as approximate lower and upper bounds for total sediment storage in the Upper Basin and 314 and 482 billion cubic meters as approximate lower and upper bounds for the Lower Basin. The largest proportion of sediment is stored in the montane and steppe zones in the Upper Basin and in the Sonoran zone in the Lower Basin.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140887589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nicole Funk, Josef Knott, Joachim Pander, Juergen Geist
Preventing fish entrainment during their downstream passage at hydropower plants remains a major challenge in reducing the ecological impacts of hydropower production. We investigated fish behavior at the world's first innovative shaft hydropower plant with its novel screen concept, aiming at reducing fish entrainment due to the fully horizontal arrangement of the screen and low vertical suction effects toward the turbine. Based on ARIS sonar recordings, we assessed whether fish could move unhindered across the turbine intake area toward the bypass corridors at the sluice gate for safe downstream passage. For a range of species (Anguilla anguilla, Barbus barbus, Thymallus thymallus, Salmo trutta, and Hucho hucho) and operation modes (high/low turbine load), we assessed behavioral patterns such as screen avoidance, dwelling behavior, and search behavior at the screen. Contrary to the engineers' expectations, the innovative screen arrangement neither guided the fish away from the turbine intake to the bypass corridors nor prevented them from swimming vertically into the turbine shaft. Rather, fish freely moved near the screen and avoidance behavior was only rarely observed. Both the dwelling and active search behavior, which was particularly evident in eel, are directly linked to an increased risk of screen passage and subsequent turbine‐related death or injuries. Our findings illustrate that consideration of fish behavior at turbine inlet structures is a crucial component which needs to be integrated with other variables such as fish mortality and injury patterns for a comprehensive evaluation and improvement of fish passage at hydropower plants.
{"title":"Fish behavior at the horizontal screen of a novel shaft hydropower plant","authors":"Nicole Funk, Josef Knott, Joachim Pander, Juergen Geist","doi":"10.1002/rra.4302","DOIUrl":"https://doi.org/10.1002/rra.4302","url":null,"abstract":"Preventing fish entrainment during their downstream passage at hydropower plants remains a major challenge in reducing the ecological impacts of hydropower production. We investigated fish behavior at the world's first innovative shaft hydropower plant with its novel screen concept, aiming at reducing fish entrainment due to the fully horizontal arrangement of the screen and low vertical suction effects toward the turbine. Based on ARIS sonar recordings, we assessed whether fish could move unhindered across the turbine intake area toward the bypass corridors at the sluice gate for safe downstream passage. For a range of species (<jats:italic>Anguilla anguilla</jats:italic>, <jats:italic>Barbus barbus</jats:italic>, <jats:italic>Thymallus thymallus</jats:italic>, <jats:italic>Salmo trutta</jats:italic>, and <jats:italic>Hucho hucho</jats:italic>) and operation modes (high/low turbine load), we assessed behavioral patterns such as screen avoidance, dwelling behavior, and search behavior at the screen. Contrary to the engineers' expectations, the innovative screen arrangement neither guided the fish away from the turbine intake to the bypass corridors nor prevented them from swimming vertically into the turbine shaft. Rather, fish freely moved near the screen and avoidance behavior was only rarely observed. Both the dwelling and active search behavior, which was particularly evident in eel, are directly linked to an increased risk of screen passage and subsequent turbine‐related death or injuries. Our findings illustrate that consideration of fish behavior at turbine inlet structures is a crucial component which needs to be integrated with other variables such as fish mortality and injury patterns for a comprehensive evaluation and improvement of fish passage at hydropower plants.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140841323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study evaluated erosion rates and sediment production in streams, and factors potentially influencing them throughout the Anacostia, Patuxent, and Potomac (non‐Anacostia) River watersheds within Prince George's County, Maryland, US. As part of the County's watershed‐scale biological monitoring program, from approx. 1999 to 2008, permanent monuments were established to allow measurement of stream channel cross‐sectional (XS) area. The intent of this study was to characterize the intensity and spatial distribution of fluvial geomorphic instability across the county and use the results to target and plan stormwater management and stream restoration actions. For this study, 78 stream locations were re‐surveyed in 2020, representing a time lapse of from 12 to 21 years. Data collected included XS dimensions, modified Wolman 100‐particle pebble counts, and reach‐specific soil bulk density. Land use/land cover data were compiled from the National Land Cover Dataset (NLCD), precipitation from the National Weather Service Center for Environmental Information (NCEI), and soils from the Natural Resources Conservation Service Web Soil Survey (NRCS/WSS). We calculated percent change in XS area, rates of erosion, sediment yield, and assigned geomorphic classifications, and interpreted them in the context of spatial positions relative to changes in land cover characteristics. Sediment yields among the 78 reaches exhibited a combination of those undergoing enlargement/erosion (67.9%), reduction/deposition (25.6%), and the remaining 6.4% with essentially no change over the period of record. Of the top 20 most geomorphically active reaches surveyed in the County, 12 are in the Anacostia River basin, with the other scattered among the Patuxent River and Potomac River basins.
{"title":"Landscape changes and watershed erosion in Prince George's County, Maryland","authors":"James B. Stribling","doi":"10.1002/rra.4292","DOIUrl":"https://doi.org/10.1002/rra.4292","url":null,"abstract":"This study evaluated erosion rates and sediment production in streams, and factors potentially influencing them throughout the Anacostia, Patuxent, and Potomac (non‐Anacostia) River watersheds within Prince George's County, Maryland, US. As part of the County's watershed‐scale biological monitoring program, from approx. 1999 to 2008, permanent monuments were established to allow measurement of stream channel cross‐sectional (XS) area. The intent of this study was to characterize the intensity and spatial distribution of fluvial geomorphic instability across the county and use the results to target and plan stormwater management and stream restoration actions. For this study, 78 stream locations were re‐surveyed in 2020, representing a time lapse of from 12 to 21 years. Data collected included XS dimensions, modified Wolman 100‐particle pebble counts, and reach‐specific soil bulk density. Land use/land cover data were compiled from the National Land Cover Dataset (NLCD), precipitation from the National Weather Service Center for Environmental Information (NCEI), and soils from the Natural Resources Conservation Service Web Soil Survey (NRCS/WSS). We calculated percent change in XS area, rates of erosion, sediment yield, and assigned geomorphic classifications, and interpreted them in the context of spatial positions relative to changes in land cover characteristics. Sediment yields among the 78 reaches exhibited a combination of those undergoing enlargement/erosion (67.9%), reduction/deposition (25.6%), and the remaining 6.4% with essentially no change over the period of record. Of the top 20 most geomorphically active reaches surveyed in the County, 12 are in the Anacostia River basin, with the other scattered among the Patuxent River and Potomac River basins.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140842548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandra E. Ryan, Charles M. Shobe, Sara L. Rathburn, Mark K. Dixon
Wildfires, and the sediment‐rich floods that commonly follow, increasingly threaten riverine ecosystems and water infrastructure. Suspended sediment exported throughout fire–flood sequences poses particular risks due to rapid transit times and direct impacts on water quality. However, opportunities to measure suspended‐sediment transport during and after post‐fire floods, and therefore to illuminate what controls the magnitude and timing of suspended‐sediment export from burned, flooded watersheds, are rare. A ~ 100‐year flood that occurred one year into a three‐year study monitoring suspended‐sediment response to wildfire in the Colorado Front Range provides a unique opportunity to (1) quantify how suspended‐sediment concentrations and loads change throughout a fire–flood sequence, and (2) infer what controls the timescale over which suspended‐sediment dynamics recover toward pre‐fire conditions. We find that suspended‐sediment concentrations (SSCs) during summer storms declined monotonically to background conditions over 3 years. Snowmelt SSCs peaked in the second year before declining to background levels. Sediment load calculations reveal that the flood exported ~35 years' worth of suspended sediment and triggered ~1.5 years of elevated SSCs and sediment loads. SSCs and sediment loads indicate a fairly short post‐fire recovery timescale of about 3 years. We suggest that the flood accelerated recovery by (1) exporting much of the available suspended sediment from this supply‐limited landscape and (2) facilitating the export of remaining sediment by making it more accessible to subsequent flows. Our results indicate that large post‐wildfire floods, though representing major geomorphic disturbances, may hasten post‐fire suspended‐sediment recovery to background conditions, at least in supply‐limited regions.
{"title":"Suspended‐sediment response to wildfire and a major post‐fire flood on the Colorado Front Range","authors":"Sandra E. Ryan, Charles M. Shobe, Sara L. Rathburn, Mark K. Dixon","doi":"10.1002/rra.4286","DOIUrl":"https://doi.org/10.1002/rra.4286","url":null,"abstract":"Wildfires, and the sediment‐rich floods that commonly follow, increasingly threaten riverine ecosystems and water infrastructure. Suspended sediment exported throughout fire–flood sequences poses particular risks due to rapid transit times and direct impacts on water quality. However, opportunities to measure suspended‐sediment transport during and after post‐fire floods, and therefore to illuminate what controls the magnitude and timing of suspended‐sediment export from burned, flooded watersheds, are rare. A ~ 100‐year flood that occurred one year into a three‐year study monitoring suspended‐sediment response to wildfire in the Colorado Front Range provides a unique opportunity to (1) quantify how suspended‐sediment concentrations and loads change throughout a fire–flood sequence, and (2) infer what controls the timescale over which suspended‐sediment dynamics recover toward pre‐fire conditions. We find that suspended‐sediment concentrations (SSCs) during summer storms declined monotonically to background conditions over 3 years. Snowmelt SSCs peaked in the second year before declining to background levels. Sediment load calculations reveal that the flood exported ~35 years' worth of suspended sediment and triggered ~1.5 years of elevated SSCs and sediment loads. SSCs and sediment loads indicate a fairly short post‐fire recovery timescale of about 3 years. We suggest that the flood accelerated recovery by (1) exporting much of the available suspended sediment from this supply‐limited landscape and (2) facilitating the export of remaining sediment by making it more accessible to subsequent flows. Our results indicate that large post‐wildfire floods, though representing major geomorphic disturbances, may hasten post‐fire suspended‐sediment recovery to background conditions, at least in supply‐limited regions.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140811616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study assessed the functional effectiveness in terms of passage proportion of three fishways, one nature‐like bypass, one partly nature‐like bypass and partly technical pool‐type and one completely technical, on the Pinka Stream and Rába River in Western Hungary. Radio frequency identification with passive integrated transponder tagging was used to collect data on the upstream passage. A total of 2976 tagged individuals were included in the study; 2863 individuals were either barbel (Barbus barbus), nase (Chondrostoma nasus) or chub (Squalius cephalus), which were chosen as model species, and 113 individuals belonged to four other species. There were 540 individuals of the model species and 18 individuals of the other species detected while successfully ascending one of the fishways. The time‐to‐event (survival) analysis of the data of the model species revealed significant species‐specific differences in passage probability between the fishways. The passage probabilities of the barbel were the highest, and those of the nase were the lowest at all three fishways. The findings demonstrate that single‐species evaluations can lead to incorrect conclusions on fishway effectiveness. Technical fishways can be as effective as nature‐like ones, and hybrid solutions (technical fishways combined with nature‐like bypasses) can function as well. The limitations of the study and recommendations for further evaluations are also discussed.
{"title":"Effectiveness of fishways on the Pinka Stream and the Rába River, Central Europe: An evaluation with species from the order Cypriniformes","authors":"Péter Sály, Márton Sallai, Zoltán Sallai","doi":"10.1002/rra.4285","DOIUrl":"https://doi.org/10.1002/rra.4285","url":null,"abstract":"This study assessed the functional effectiveness in terms of passage proportion of three fishways, one nature‐like bypass, one partly nature‐like bypass and partly technical pool‐type and one completely technical, on the Pinka Stream and Rába River in Western Hungary. Radio frequency identification with passive integrated transponder tagging was used to collect data on the upstream passage. A total of 2976 tagged individuals were included in the study; 2863 individuals were either barbel (<jats:italic>Barbus barbus</jats:italic>), nase (<jats:italic>Chondrostoma nasus</jats:italic>) or chub (<jats:italic>Squalius cephalus</jats:italic>), which were chosen as model species, and 113 individuals belonged to four other species. There were 540 individuals of the model species and 18 individuals of the other species detected while successfully ascending one of the fishways. The time‐to‐event (survival) analysis of the data of the model species revealed significant species‐specific differences in passage probability between the fishways. The passage probabilities of the barbel were the highest, and those of the nase were the lowest at all three fishways. The findings demonstrate that single‐species evaluations can lead to incorrect conclusions on fishway effectiveness. Technical fishways can be as effective as nature‐like ones, and hybrid solutions (technical fishways combined with nature‐like bypasses) can function as well. The limitations of the study and recommendations for further evaluations are also discussed.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140811523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intermittent streams exhibit regular patterns of drying and are widespread, but the patterns of drying among streams within geographic proximity are not fully understood. We compared annual patterns of flow and drying among 10 intermittent streams within a single drainage basin and assessed how traditional hydrologic metrics described variation between streams. We installed stream intermittency sensors and evaluated stage height using low‐cost methods and evaluated landscape factors as potential drivers of flow patterns. Intermittent streams varied based on both high‐ and low‐flow metrics, driven by a variety of landscape‐level factors, especially watershed size. Additionally, we compared the observed flow regimes within our system with predictions generated using an established Soil and Water Assessment Tool, finding that modeled streamflow patterns generally underrepresented observed drying within the system.
{"title":"Dry, drier, driest: Differentiating flow patterns across a gradient of intermittency","authors":"Benjamin T. Kelly, L. Bruckerhoff","doi":"10.1002/rra.4289","DOIUrl":"https://doi.org/10.1002/rra.4289","url":null,"abstract":"Intermittent streams exhibit regular patterns of drying and are widespread, but the patterns of drying among streams within geographic proximity are not fully understood. We compared annual patterns of flow and drying among 10 intermittent streams within a single drainage basin and assessed how traditional hydrologic metrics described variation between streams. We installed stream intermittency sensors and evaluated stage height using low‐cost methods and evaluated landscape factors as potential drivers of flow patterns. Intermittent streams varied based on both high‐ and low‐flow metrics, driven by a variety of landscape‐level factors, especially watershed size. Additionally, we compared the observed flow regimes within our system with predictions generated using an established Soil and Water Assessment Tool, finding that modeled streamflow patterns generally underrepresented observed drying within the system.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140673802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ability of plants to colonize the fluvial environment and withstand uprooting by floods is largely controlled by the anchoring effect of roots. We characterized the root architecture and tensile strength of Alnus incana, a riparian tree species of the Betulaceae family for which there are no systematic observations of its vertical root structure. Four A. incana individuals and two nearby Populus nigra 3–10 years old growing on bars in gravel‐bed rivers were excavated. Their root structure was characterized in terms of root diameter, age, and depth and was related to sediment grain size and scour or deposition by floods. Root tensile strength was also measured as a function of root diameter using a load cell and displacement transducer attached to individual roots. The architecture of A. incana roots differed from that of nearby P. nigra, as all roots were in fine, sandy sediments, growing in one or more dense radial layers of which the most prominent was 0.2–0.3 m below the surface. The layers reflect deposition of fine sediments during floods. New fine sediment deposits promote the growth of a new root layer close to the aggraded ground surface. Root tensile strength was similar to Salicaceae species. These observations indicate that A. incana colonizes habitats that have already received fine sediment deposition, most likely induced by other young plants, especially Salicaceae species. A. incana then provides a high near‐surface root biomass, potentially further stabilizing surfaces and playing a complementary role as an ecosystem engineer.
{"title":"Vertical root profiles of grey alder (Alnus incana) trees growing in highly disturbed river environments","authors":"Matteo Stamer, A. Gurnell, W. Bertoldi","doi":"10.1002/rra.4287","DOIUrl":"https://doi.org/10.1002/rra.4287","url":null,"abstract":"The ability of plants to colonize the fluvial environment and withstand uprooting by floods is largely controlled by the anchoring effect of roots. We characterized the root architecture and tensile strength of Alnus incana, a riparian tree species of the Betulaceae family for which there are no systematic observations of its vertical root structure. Four A. incana individuals and two nearby Populus nigra 3–10 years old growing on bars in gravel‐bed rivers were excavated. Their root structure was characterized in terms of root diameter, age, and depth and was related to sediment grain size and scour or deposition by floods. Root tensile strength was also measured as a function of root diameter using a load cell and displacement transducer attached to individual roots. The architecture of A. incana roots differed from that of nearby P. nigra, as all roots were in fine, sandy sediments, growing in one or more dense radial layers of which the most prominent was 0.2–0.3 m below the surface. The layers reflect deposition of fine sediments during floods. New fine sediment deposits promote the growth of a new root layer close to the aggraded ground surface. Root tensile strength was similar to Salicaceae species. These observations indicate that A. incana colonizes habitats that have already received fine sediment deposition, most likely induced by other young plants, especially Salicaceae species. A. incana then provides a high near‐surface root biomass, potentially further stabilizing surfaces and playing a complementary role as an ecosystem engineer.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140672547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. van Rijssel, A. W. Breukelaar, J. J. de Leeuw, M. E. B. van Puijenbroek, K. Schilder, A. Schrimpf, F. T. Vriese, H. V. Winter
Freshwater species biodiversity is under threat. The average global decline for migratory fish species is estimated to be more than 75% since 1970. Atlantic salmon is one of these species with a steep decline in north‐western Europe and it even went extinct in the river Rhine in the 1950s. The causes for this decline have been posted to habitat loss, pollution, climate change and overfishing. Annual stocking in the Rhine since the late 1980s resulted in an initial increase in the Atlantic salmon numbers after which numbers collapsed again. In this paper, we lay out the recent decline, estimate losses of smolts and adults at different sections in the freshwater habitat and elaborate on potential causes of the recent decline and these losses. We found that the salmon population of the river Rhine has declined rapidly over the past two decades, with a current estimated spawning population of only ~350–800 individuals. The percentage of salmon smolts returning as adults to spawning grounds is estimated at 0.5%–0.6%, well below the 3% supposedly needed to maintain a self‐sustaining population. Many individuals disappear during their migrations, with the highest percentage of smolts disappearing in the German tributaries (44%) and the Dutch lower Rhine (71%), while the percentage of disappearing adults is highest in both the Dutch (74%) and the German (78%) Rhine. Causes for the losses per river section remain unclear and possible threats, some specific to the river Rhine, are being discussed. The large losses of smolts and adults in inland waters, compared with open sea losses, indicate that restocking the river Rhine might only result in a self‐sustaining population with more ecological restoration than carried out so far along the intensively shipped and highly regulated river course and associated high levels of predation, and might be increasingly limited by future climate change.
{"title":"Reintroducing Atlantic salmon in the river Rhine for decades: Why did it not result in the return of a viable population?","authors":"J. van Rijssel, A. W. Breukelaar, J. J. de Leeuw, M. E. B. van Puijenbroek, K. Schilder, A. Schrimpf, F. T. Vriese, H. V. Winter","doi":"10.1002/rra.4284","DOIUrl":"https://doi.org/10.1002/rra.4284","url":null,"abstract":"Freshwater species biodiversity is under threat. The average global decline for migratory fish species is estimated to be more than 75% since 1970. Atlantic salmon is one of these species with a steep decline in north‐western Europe and it even went extinct in the river Rhine in the 1950s. The causes for this decline have been posted to habitat loss, pollution, climate change and overfishing. Annual stocking in the Rhine since the late 1980s resulted in an initial increase in the Atlantic salmon numbers after which numbers collapsed again. In this paper, we lay out the recent decline, estimate losses of smolts and adults at different sections in the freshwater habitat and elaborate on potential causes of the recent decline and these losses. We found that the salmon population of the river Rhine has declined rapidly over the past two decades, with a current estimated spawning population of only ~350–800 individuals. The percentage of salmon smolts returning as adults to spawning grounds is estimated at 0.5%–0.6%, well below the 3% supposedly needed to maintain a self‐sustaining population. Many individuals disappear during their migrations, with the highest percentage of smolts disappearing in the German tributaries (44%) and the Dutch lower Rhine (71%), while the percentage of disappearing adults is highest in both the Dutch (74%) and the German (78%) Rhine. Causes for the losses per river section remain unclear and possible threats, some specific to the river Rhine, are being discussed. The large losses of smolts and adults in inland waters, compared with open sea losses, indicate that restocking the river Rhine might only result in a self‐sustaining population with more ecological restoration than carried out so far along the intensively shipped and highly regulated river course and associated high levels of predation, and might be increasingly limited by future climate change.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140678781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ali Mchayk, H. Marttila, Björn Klöve, Ali Torabi Haghighi
The role of hydropower as a renewable and balancing power source is expected to increase in a Net Zero Emissions by 2050 scenario. As a common phenomenon in hydropower plants, hydropeaking will become more prominent, resulting in additional stresses on the ecological status of rivers. Here we propose a novel approach to design and operate auxiliary reservoirs called re‐regulation reservoirs (RRR) that aim to mitigate the adverse impacts of hydropeaking on rivers. A re‐regulation reservoir aims at smoothing flow fluctuations caused by hydropeaking by diverting and retaining parts of high flows and returning them back to river corridors during low flows. Using actual data from a hydropeaking‐influenced river system, the operation and efficiency of potential reservoirs have been investigated. An open‐access algorithm was developed to analyze the influence of the reservoirs to mitigate hydropeaking, considering peak and minimum flow and up‐ and down‐ramping rates. The findings illustrate that, in most cases, the required reservoir volume increases as the flow thresholds become more stringent. Nonetheless, several exceptions were observed, where larger reservoir volumes were required compared with cases with more stringent thresholds. These findings highlight the importance of understanding the impact of flow adjustments, while carefully considering the river regime, sub‐daily flow patterns, and unique characteristics of the river's ecosystem. Our approach shows theoretical possibilities for regulating hydropeaking and provides a basis for optimizing re‐regulation reservoirs, contributing to practical and adaptable strategies for sustainable hydropower management without increasing the operational cost of power systems.
{"title":"Hydropeaking mitigation with re‐regulation reservoirs","authors":"Ali Mchayk, H. Marttila, Björn Klöve, Ali Torabi Haghighi","doi":"10.1002/rra.4290","DOIUrl":"https://doi.org/10.1002/rra.4290","url":null,"abstract":"The role of hydropower as a renewable and balancing power source is expected to increase in a Net Zero Emissions by 2050 scenario. As a common phenomenon in hydropower plants, hydropeaking will become more prominent, resulting in additional stresses on the ecological status of rivers. Here we propose a novel approach to design and operate auxiliary reservoirs called re‐regulation reservoirs (RRR) that aim to mitigate the adverse impacts of hydropeaking on rivers. A re‐regulation reservoir aims at smoothing flow fluctuations caused by hydropeaking by diverting and retaining parts of high flows and returning them back to river corridors during low flows. Using actual data from a hydropeaking‐influenced river system, the operation and efficiency of potential reservoirs have been investigated. An open‐access algorithm was developed to analyze the influence of the reservoirs to mitigate hydropeaking, considering peak and minimum flow and up‐ and down‐ramping rates. The findings illustrate that, in most cases, the required reservoir volume increases as the flow thresholds become more stringent. Nonetheless, several exceptions were observed, where larger reservoir volumes were required compared with cases with more stringent thresholds. These findings highlight the importance of understanding the impact of flow adjustments, while carefully considering the river regime, sub‐daily flow patterns, and unique characteristics of the river's ecosystem. Our approach shows theoretical possibilities for regulating hydropeaking and provides a basis for optimizing re‐regulation reservoirs, contributing to practical and adaptable strategies for sustainable hydropower management without increasing the operational cost of power systems.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140678091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Continued declines in freshwater biodiversity and the challenges of climate change are creating greater interest in river restoration projects. Increasing recognition of the interaction between biological, geomorphological and hydrological processes has led to the development of ‘Stage 0’ river restoration. Stage 0 reaches are typically multi‐thread anabranching systems connected to the floodplain and its ecosystems. It is suggested that the defining characteristic of Stage 0 conditions is that of connectivity (longitudinal, lateral and vertical) at base flows. The methods or mechanisms that can re‐create such reaches are described, namely valley floor reset, beaver activity, beaver dam analogues and the use of large wood in the channel and floodplain. The scope for wider adoption of Stage 0 is then discussed and recommendations for expanding this approach across temperate regions with a long history of river modification and higher population densities are presented.
{"title":"Full floodplain connectivity: Realising opportunities for ‘Stage 0’ river restoration","authors":"Stewart J. Clarke","doi":"10.1002/rra.4283","DOIUrl":"https://doi.org/10.1002/rra.4283","url":null,"abstract":"Continued declines in freshwater biodiversity and the challenges of climate change are creating greater interest in river restoration projects. Increasing recognition of the interaction between biological, geomorphological and hydrological processes has led to the development of ‘Stage 0’ river restoration. Stage 0 reaches are typically multi‐thread anabranching systems connected to the floodplain and its ecosystems. It is suggested that the defining characteristic of Stage 0 conditions is that of connectivity (longitudinal, lateral and vertical) at base flows. The methods or mechanisms that can re‐create such reaches are described, namely valley floor reset, beaver activity, beaver dam analogues and the use of large wood in the channel and floodplain. The scope for wider adoption of Stage 0 is then discussed and recommendations for expanding this approach across temperate regions with a long history of river modification and higher population densities are presented.","PeriodicalId":21513,"journal":{"name":"River Research and Applications","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140609568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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