Pub Date : 2021-11-04DOI: 10.1080/15715124.2021.2000426
S. Maheshwari, S. Chavan
ABSTRACT Discharge indices based on mean sediment load such as fraction-load (f-load) discharge and functional-equivalent discharge represent long-term sediment transfer through river networks. These discharge indices can be used as design flows for the restoration of river channels and in geomorphic and eco-hydrologic studies. In this paper, lognormal distribution-based and Gamma distribution-based Magnitude-Frequency Analysis (MFA) approaches are evaluated to determine reliable estimates of discharge indices for suspended sediment transport in South Indian catchments. The discharge indices are estimated by considering (i) total suspended sediment load and (ii) fine, medium, and coarse suspended sediment loads, separately, as various fractions of suspended sediments have different hydraulic characteristics, transport behaviour, and effect on the ecological system. Results indicate that the lognormal distribution being heavy-tailed tends to assign considerable frequency densities to higher discharges which results in unreliable and magnified estimates of mean sediment load and subsequent discharge indices for most of the catchments. Overall, the Gamma distribution-based MFA approach is found to yield reliable estimates of the f-load discharge and functional-equivalent discharge in comparison to the lognormal distribution-based MFA approach.
{"title":"Evaluation of approaches to estimate discharge indices based on mean sediment load for suspended sediment transport in South Indian catchments","authors":"S. Maheshwari, S. Chavan","doi":"10.1080/15715124.2021.2000426","DOIUrl":"https://doi.org/10.1080/15715124.2021.2000426","url":null,"abstract":"ABSTRACT Discharge indices based on mean sediment load such as fraction-load (f-load) discharge and functional-equivalent discharge represent long-term sediment transfer through river networks. These discharge indices can be used as design flows for the restoration of river channels and in geomorphic and eco-hydrologic studies. In this paper, lognormal distribution-based and Gamma distribution-based Magnitude-Frequency Analysis (MFA) approaches are evaluated to determine reliable estimates of discharge indices for suspended sediment transport in South Indian catchments. The discharge indices are estimated by considering (i) total suspended sediment load and (ii) fine, medium, and coarse suspended sediment loads, separately, as various fractions of suspended sediments have different hydraulic characteristics, transport behaviour, and effect on the ecological system. Results indicate that the lognormal distribution being heavy-tailed tends to assign considerable frequency densities to higher discharges which results in unreliable and magnified estimates of mean sediment load and subsequent discharge indices for most of the catchments. Overall, the Gamma distribution-based MFA approach is found to yield reliable estimates of the f-load discharge and functional-equivalent discharge in comparison to the lognormal distribution-based MFA approach.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"339 - 355"},"PeriodicalIF":2.5,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47473827","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}
Pub Date : 2021-11-04DOI: 10.1080/15715124.2021.2000427
Rej Winlove M. Bungabong, W. Hadwen, L. Padilla
ABSTRACT Check dams, installed to control sediment and flood risk along streams, can significantly influence the hydrology and ecology of aquatic ecosystems. Few studies assessing its impacts have been done in some countries, however, such has not been the case in the Philippines. Implementation of check dam projects in the Philippines has not been paired with monitoring and evaluation strategies to determine their success or impacts in relation to their objective to manage sediment and flow. This study focused on assessing check dams impacts on hydrology, biology, and stakeholders reflection on check dam purpose and success in Upper Marikina River Basin Protected Landscape (UMRBPL), Philippines. To explore the balance in socioeconomic and ecological sustainability of check dam installation, interviews with stakeholders revealed a wide range of perceptions around the project’s success and potential impacts. The findings revealed a clear need for the enhancement of the enabling environment (i.e. data baselining and implementation of management strategies) and institutional arrangements (i.e. coordinated management action). There is also an urgent need for the development of management instruments (i.e. monitoring and evaluation programme and communication and awareness strategy) to improve stakeholders’ understanding of the project’s objectives and outcomes and to improve sustainable management throughout UMRBPL.
{"title":"Critical evaluation of the hydrological, biological and sociological impacts of the implementation of flood control check dams in the Upper Marikina River Basin Protected Landscape, Philippines","authors":"Rej Winlove M. Bungabong, W. Hadwen, L. Padilla","doi":"10.1080/15715124.2021.2000427","DOIUrl":"https://doi.org/10.1080/15715124.2021.2000427","url":null,"abstract":"ABSTRACT Check dams, installed to control sediment and flood risk along streams, can significantly influence the hydrology and ecology of aquatic ecosystems. Few studies assessing its impacts have been done in some countries, however, such has not been the case in the Philippines. Implementation of check dam projects in the Philippines has not been paired with monitoring and evaluation strategies to determine their success or impacts in relation to their objective to manage sediment and flow. This study focused on assessing check dams impacts on hydrology, biology, and stakeholders reflection on check dam purpose and success in Upper Marikina River Basin Protected Landscape (UMRBPL), Philippines. To explore the balance in socioeconomic and ecological sustainability of check dam installation, interviews with stakeholders revealed a wide range of perceptions around the project’s success and potential impacts. The findings revealed a clear need for the enhancement of the enabling environment (i.e. data baselining and implementation of management strategies) and institutional arrangements (i.e. coordinated management action). There is also an urgent need for the development of management instruments (i.e. monitoring and evaluation programme and communication and awareness strategy) to improve stakeholders’ understanding of the project’s objectives and outcomes and to improve sustainable management throughout UMRBPL.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"357 - 373"},"PeriodicalIF":2.5,"publicationDate":"2021-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47657221","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}
Pub Date : 2021-09-23DOI: 10.1080/15715124.2021.1981353
Sepideh Mofidi, A. Mohammadi Torkashvand, A. Moeini, E. Pazira, H. Ahmadi
ABSTRACT The network of streams continuously changes its location based on time, environmental factors and human interventions. It is very important to study the stream changes in order to provide management solutions for soil conservation. One of the new methods in this regard is to use fractal geometry. The purpose of this study was to investigate the relationship between fractal and morphometric characteristics of the basin and the possibility of fast, low-cost and accurate management of the stream network based on this relationship. For this purpose, using data basic maps, drainage networks map and digital elevation model (10 m) of the ground by ArcGIS 10.7 was prepared. Then applying the rules of the Horton–Strahler river network, fractal dimensions were calculated to examine the relationship between fractal dimensions, and some rivers’ geomorphic features were investigated. Finally, by entering the data obtained from the calculations in SPSS 22 and Curve Expert software, the morphometric characteristics of the basin associated with the fractal dimensions were investigated. In the Curve Expert software, the exponential, logarithmic, linear and power models of the dependent variable (fractal dimension) and the independent variable (morphometric characteristics) were investigated and the model that had the higher determination coefficient and was significant in SPSS 22 software for the nonlinear univariate regression was selected and introduced as the appropriate model for the relationship between the two studied variables. Results showed that the fractal dimension of stream branch, the fractal dimension of drainage density and the fractal dimension of total basin area were 1.84, 0.71 and 1.46, respectively. The results also showed that the fractal dimension of watersheds has meaningful relations with factors such as shape form, area, bifurcation ratio and length ratio in the watersheds. Due to the importance of stream characteristics in the management of watersheds in terms of flood, erosion and soil conservation, the fractal models can be used to make quick and accurate decisions about the stream management.
{"title":"Relationship between fractal dimensions of stream and morphometric characteristics of basin for the soil conservation from water erosion","authors":"Sepideh Mofidi, A. Mohammadi Torkashvand, A. Moeini, E. Pazira, H. Ahmadi","doi":"10.1080/15715124.2021.1981353","DOIUrl":"https://doi.org/10.1080/15715124.2021.1981353","url":null,"abstract":"ABSTRACT The network of streams continuously changes its location based on time, environmental factors and human interventions. It is very important to study the stream changes in order to provide management solutions for soil conservation. One of the new methods in this regard is to use fractal geometry. The purpose of this study was to investigate the relationship between fractal and morphometric characteristics of the basin and the possibility of fast, low-cost and accurate management of the stream network based on this relationship. For this purpose, using data basic maps, drainage networks map and digital elevation model (10 m) of the ground by ArcGIS 10.7 was prepared. Then applying the rules of the Horton–Strahler river network, fractal dimensions were calculated to examine the relationship between fractal dimensions, and some rivers’ geomorphic features were investigated. Finally, by entering the data obtained from the calculations in SPSS 22 and Curve Expert software, the morphometric characteristics of the basin associated with the fractal dimensions were investigated. In the Curve Expert software, the exponential, logarithmic, linear and power models of the dependent variable (fractal dimension) and the independent variable (morphometric characteristics) were investigated and the model that had the higher determination coefficient and was significant in SPSS 22 software for the nonlinear univariate regression was selected and introduced as the appropriate model for the relationship between the two studied variables. Results showed that the fractal dimension of stream branch, the fractal dimension of drainage density and the fractal dimension of total basin area were 1.84, 0.71 and 1.46, respectively. The results also showed that the fractal dimension of watersheds has meaningful relations with factors such as shape form, area, bifurcation ratio and length ratio in the watersheds. Due to the importance of stream characteristics in the management of watersheds in terms of flood, erosion and soil conservation, the fractal models can be used to make quick and accurate decisions about the stream management.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"299 - 309"},"PeriodicalIF":2.5,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46973167","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}
Pub Date : 2021-09-23DOI: 10.1080/15715124.2021.1981355
Necla Koralay, Ö. Kara
ABSTRACT Watershed morphometry refers to the connections between systems of a watershed, such as hydrology, geology, vegetation, and topographic structure. The topographic and hydrological characteristics of the watershed have a great impact on vegetation, retention of rainwater in the soil, and its transformation into runoff, flood, and landslide occurring in the watershed. In this study, watershed morphometric analysis of the Altindere, Zigana and Catak subwatersheds located upstream of the Degirmendere watershed in Turkey was conducted, and the potential of producing floods related to these features was investigated. As the study area, Trabzon Degirmendere subwatersheds were chosen due to flood and landslide events that have occurred in the past and caused loss of life and property damage. By considering the linear, areal, and relief morphometric properties of each subwatershed, their flood effect levels and potentials are revealed. ArcGIS software was used in the analysis. Digital Elevation Model (DEM) with a resolution of 10 m produced from 1:25,000 scale topographic maps was used as a base for the evaluation of these parameters. As a result of this study, when evaluated in terms of the morphometric properties of the watersheds, it was determined that the Zigana subwatershed has the greatest impact on flood production. This study is intended to guide decision-makers to anticipate floods and flood events that will occur in the watersheds in the future.
{"title":"Effects of morphometric characteristics on flood in Degirmendere sub-watersheds, Northeastern Turkey","authors":"Necla Koralay, Ö. Kara","doi":"10.1080/15715124.2021.1981355","DOIUrl":"https://doi.org/10.1080/15715124.2021.1981355","url":null,"abstract":"ABSTRACT Watershed morphometry refers to the connections between systems of a watershed, such as hydrology, geology, vegetation, and topographic structure. The topographic and hydrological characteristics of the watershed have a great impact on vegetation, retention of rainwater in the soil, and its transformation into runoff, flood, and landslide occurring in the watershed. In this study, watershed morphometric analysis of the Altindere, Zigana and Catak subwatersheds located upstream of the Degirmendere watershed in Turkey was conducted, and the potential of producing floods related to these features was investigated. As the study area, Trabzon Degirmendere subwatersheds were chosen due to flood and landslide events that have occurred in the past and caused loss of life and property damage. By considering the linear, areal, and relief morphometric properties of each subwatershed, their flood effect levels and potentials are revealed. ArcGIS software was used in the analysis. Digital Elevation Model (DEM) with a resolution of 10 m produced from 1:25,000 scale topographic maps was used as a base for the evaluation of these parameters. As a result of this study, when evaluated in terms of the morphometric properties of the watersheds, it was determined that the Zigana subwatershed has the greatest impact on flood production. This study is intended to guide decision-makers to anticipate floods and flood events that will occur in the watersheds in the future.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"327 - 337"},"PeriodicalIF":2.5,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43289259","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}
Pub Date : 2021-09-23DOI: 10.1080/15715124.2021.1981354
Lubna AlMahasneh, Doaa Abuhamoor, K. Al Sane, N. Haddad
ABSTRACT Flash flood is among the most catastrophic hazards worldwide. Jordan has been witnessing unusual shocks of flash floods with regular intervals. It is best described as sudden events involving ‘too much water in too little time’. This study aims at presenting flash flood assessment and producing a potential flood hazard severity map. The GIS-based hydrology assessment was carried out using Rational model. The model integrates biophysical characteristics of the basin and the hydrometrological information. The range of peak discharge was around 5 MCM in the Jordan Valley to 65 MCM in W. Hammad basin. Flood hazard severity map was produced based on Integrated Context Analysis approach (ICA) at surface basin's level. It has been shown that 17.6% of Jordan's area is categorized into ‘high’ class hazard severity. The study provides consistent information at a national-scale on flood hazard reclassification to support the development of the implementation of flood management policy of flood mitigation activities. Also, it proves the usefulness of GIS technology in model preparation and parameterizations.
{"title":"Assessment and mapping of flash flood hazard severity in Jordan","authors":"Lubna AlMahasneh, Doaa Abuhamoor, K. Al Sane, N. Haddad","doi":"10.1080/15715124.2021.1981354","DOIUrl":"https://doi.org/10.1080/15715124.2021.1981354","url":null,"abstract":"ABSTRACT Flash flood is among the most catastrophic hazards worldwide. Jordan has been witnessing unusual shocks of flash floods with regular intervals. It is best described as sudden events involving ‘too much water in too little time’. This study aims at presenting flash flood assessment and producing a potential flood hazard severity map. The GIS-based hydrology assessment was carried out using Rational model. The model integrates biophysical characteristics of the basin and the hydrometrological information. The range of peak discharge was around 5 MCM in the Jordan Valley to 65 MCM in W. Hammad basin. Flood hazard severity map was produced based on Integrated Context Analysis approach (ICA) at surface basin's level. It has been shown that 17.6% of Jordan's area is categorized into ‘high’ class hazard severity. The study provides consistent information at a national-scale on flood hazard reclassification to support the development of the implementation of flood management policy of flood mitigation activities. Also, it proves the usefulness of GIS technology in model preparation and parameterizations.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"311 - 325"},"PeriodicalIF":2.5,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46766383","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}
Pub Date : 2021-09-19DOI: 10.1080/15715124.2021.1973016
Priyanka Gautam, T. Eldho, M. Behera
ABSTRACT In this study, the local scour and the associated flow hydrodynamics around a complex pier with rectangular pile-cap at three different pile-cap elevations are investigated. The pile-cap elevations were selected with respect to the initial sand bed, such that the pile-cap was unexposed (case I), partially exposed (case II), and fully exposed (case III) to the flow. The experiments were performed in a recirculating flume under clear-water scour conditions, and the instantaneous flow velocity was obtained at different vertical planes using the particle image velocimetry (PIV) technique. The partially exposed pile-cap case showed the maximum obtained scour-depth (MSD). The reason behind the MSD occurrence in case II was enunciated through the analysis of turbulent flow field which showed that as the pile-cap got exposed to the flow, it dominantly affected the generation of vortices from the pile-cap corners responsible for the higher scour depth. The effect of the pile-cap on the flow field was prominently seen in case III through the mean velocities, vorticity, Reynolds shear stresses and turbulent kinetic energy contours, but since the pile-cap was away from the bed, the pile-cap corners did not show any direct effect on the scour.
{"title":"Effects of pile-cap elevation on scour and turbulence around a complex bridge pier","authors":"Priyanka Gautam, T. Eldho, M. Behera","doi":"10.1080/15715124.2021.1973016","DOIUrl":"https://doi.org/10.1080/15715124.2021.1973016","url":null,"abstract":"ABSTRACT In this study, the local scour and the associated flow hydrodynamics around a complex pier with rectangular pile-cap at three different pile-cap elevations are investigated. The pile-cap elevations were selected with respect to the initial sand bed, such that the pile-cap was unexposed (case I), partially exposed (case II), and fully exposed (case III) to the flow. The experiments were performed in a recirculating flume under clear-water scour conditions, and the instantaneous flow velocity was obtained at different vertical planes using the particle image velocimetry (PIV) technique. The partially exposed pile-cap case showed the maximum obtained scour-depth (MSD). The reason behind the MSD occurrence in case II was enunciated through the analysis of turbulent flow field which showed that as the pile-cap got exposed to the flow, it dominantly affected the generation of vortices from the pile-cap corners responsible for the higher scour depth. The effect of the pile-cap on the flow field was prominently seen in case III through the mean velocities, vorticity, Reynolds shear stresses and turbulent kinetic energy contours, but since the pile-cap was away from the bed, the pile-cap corners did not show any direct effect on the scour.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"283 - 297"},"PeriodicalIF":2.5,"publicationDate":"2021-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43941255","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}
Pub Date : 2021-09-06DOI: 10.1080/15715124.2021.1961796
A. D’Ippolito, F. Calomino, G. Alfonsi, A. Lauria
ABSTRACT Along the banks of rivers, trees and bushes are often planted in a single line. In the case of trees, the trunks are simulated in hydraulic laboratories by a set of cylinders, and the drag coefficient can be estimated with the use of various different methodologies, including by direct measurement, using the momentum equation, equating turbulence intensity and drag force, numerical modeling, and genetic programming. However, for the sake of simplicity, many equations have been proposed in the scientific literature that allows its immediate estimation. Some of these equations are used in this work to verify their ability to reproduce experimental data obtained for in-line cylinders by Mulahasan and Stoesser ([2017]. Flow resistance of in-line vegetation in open channel flow. International Journal of River Basin Management, 15(3), 329–334. https://doi.org/10.1080/15715124.2017.1307847), who obtained the drag force by applying the momentum equation. Several statistical descriptors have been used for this purpose. We found that the equations derived from staggered and random arrangements generally overestimate by a large amount the CD values; instead, a few relationships and in particular one derived from a squared arrangement provide much better results.
{"title":"Drag coefficient of in-line emergent vegetation in open channel flow","authors":"A. D’Ippolito, F. Calomino, G. Alfonsi, A. Lauria","doi":"10.1080/15715124.2021.1961796","DOIUrl":"https://doi.org/10.1080/15715124.2021.1961796","url":null,"abstract":"ABSTRACT Along the banks of rivers, trees and bushes are often planted in a single line. In the case of trees, the trunks are simulated in hydraulic laboratories by a set of cylinders, and the drag coefficient can be estimated with the use of various different methodologies, including by direct measurement, using the momentum equation, equating turbulence intensity and drag force, numerical modeling, and genetic programming. However, for the sake of simplicity, many equations have been proposed in the scientific literature that allows its immediate estimation. Some of these equations are used in this work to verify their ability to reproduce experimental data obtained for in-line cylinders by Mulahasan and Stoesser ([2017]. Flow resistance of in-line vegetation in open channel flow. International Journal of River Basin Management, 15(3), 329–334. https://doi.org/10.1080/15715124.2017.1307847), who obtained the drag force by applying the momentum equation. Several statistical descriptors have been used for this purpose. We found that the equations derived from staggered and random arrangements generally overestimate by a large amount the CD values; instead, a few relationships and in particular one derived from a squared arrangement provide much better results.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"253 - 263"},"PeriodicalIF":2.5,"publicationDate":"2021-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15715124.2021.1961796","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46152062","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}
Pub Date : 2021-08-22DOI: 10.1080/15715124.2021.1969943
H. Djan'na Koubodana, J. Adounkpe, K. Atchonouglo, Koffi Djaman, I. Larbi, Y. Lombo, K. Kpemoua
ABSTRACT The sub-tropical region of West Africa is not only vulnerable to the negative effects of climate change but also to the changes in land management. The goal of this study was to model streamflow in the Mono River Basin (MRB) for the period before (1964–1986) and after (1988–2011) dam construction. The Soil and Water Assessment Tool (SWAT) using input data such as a digital elevation model, soil and land use, and daily climate data model was set up, calibrated and validated for the period before dam construction (SIM1) and after dam construction (SIM2). The model sensitivity analysis, calibration and uncertainty analysis were performed based on daily observed streamflow using the Sequential Uncertainty Fitting procedure (SUFI-2) algorithm. The change in seasonal and annual streamflow between SIM1 and SIM2 was assessed and linked with land use/cover change between 1975 and 2000. The SWAT model shows satisfactory performance with Kling-Gupta Efficiency (KGE) ≥ 0.60 and percent bias |PBIAS| ≤ ±20 during calibration and KGE ≥ 0.50 and |PBIAS| ≤ ±15 during validation of SIM1 and SIM2. The results further showed that the construction of the dam affected the hydrological system of the catchment with a change in annual average streamflow between SIM1 and SIM2 of −14.13%, −19.86% and 3.66% at Athiéme, Tététou and Corrokope stations, respectively. The simulated average streamflow amplitude of SIM2 has decreased globally compared to SIM1. Therefore, the changes detected in land use/cover may have affected the average streamflow in response to the difference in amplitude simulated streamflow of SIM1 and SIM2. The finding of this analysis demonstrated that the impacts of dam construction on streamflow are challenging and crucial for water resource management in MRB.
{"title":"Modelling of streamflow before and after dam construction in the Mono River Basin in Togo-Benin, West Africa","authors":"H. Djan'na Koubodana, J. Adounkpe, K. Atchonouglo, Koffi Djaman, I. Larbi, Y. Lombo, K. Kpemoua","doi":"10.1080/15715124.2021.1969943","DOIUrl":"https://doi.org/10.1080/15715124.2021.1969943","url":null,"abstract":"ABSTRACT The sub-tropical region of West Africa is not only vulnerable to the negative effects of climate change but also to the changes in land management. The goal of this study was to model streamflow in the Mono River Basin (MRB) for the period before (1964–1986) and after (1988–2011) dam construction. The Soil and Water Assessment Tool (SWAT) using input data such as a digital elevation model, soil and land use, and daily climate data model was set up, calibrated and validated for the period before dam construction (SIM1) and after dam construction (SIM2). The model sensitivity analysis, calibration and uncertainty analysis were performed based on daily observed streamflow using the Sequential Uncertainty Fitting procedure (SUFI-2) algorithm. The change in seasonal and annual streamflow between SIM1 and SIM2 was assessed and linked with land use/cover change between 1975 and 2000. The SWAT model shows satisfactory performance with Kling-Gupta Efficiency (KGE) ≥ 0.60 and percent bias |PBIAS| ≤ ±20 during calibration and KGE ≥ 0.50 and |PBIAS| ≤ ±15 during validation of SIM1 and SIM2. The results further showed that the construction of the dam affected the hydrological system of the catchment with a change in annual average streamflow between SIM1 and SIM2 of −14.13%, −19.86% and 3.66% at Athiéme, Tététou and Corrokope stations, respectively. The simulated average streamflow amplitude of SIM2 has decreased globally compared to SIM1. Therefore, the changes detected in land use/cover may have affected the average streamflow in response to the difference in amplitude simulated streamflow of SIM1 and SIM2. The finding of this analysis demonstrated that the impacts of dam construction on streamflow are challenging and crucial for water resource management in MRB.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"265 - 281"},"PeriodicalIF":2.5,"publicationDate":"2021-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43066224","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}
Pub Date : 2021-08-17DOI: 10.1080/15715124.2021.1961795
Robert L. Miller
ABSTRACT This study evaluates the salinity response to dredging under different forcing regimes for a 75-kilometer segment of the flood-prone Vermilion River located in coastal Louisiana, USA. The Vermilion is a tidal freshwater river affected by baseflow regulation, rapid urbanization, and hydromodification. This river also serves as major freshwater resource for the region. An efficient one-dimensional model calibrated previously for stage and water temperature is used to analyse the salinity impacts due to a large-scale flood control dredging. The analysis is based on 200 alternative scenarios based on combinations of uncertain key forcing variables for a critical 13-day intrusion period. The analysis reveals a nonlinear effect on mean salinities and position of the brackish water limit as a function of uncertain forcing variables. Dredging also increases the variability of salinity encroachment effects due to uncertainty in future forcing conditions (e.g. relative sea level rise, baseflow diversion volumes, and salinities at the river mouth). The robust analysis presented here provides a foundation for future model-based assessments of under-studied tidal freshwater rivers and provides key insights for coastal management and sustainability efforts in general.
{"title":"Forcing uncertainty and salinity response to dredging in a tidal freshwater river","authors":"Robert L. Miller","doi":"10.1080/15715124.2021.1961795","DOIUrl":"https://doi.org/10.1080/15715124.2021.1961795","url":null,"abstract":"ABSTRACT This study evaluates the salinity response to dredging under different forcing regimes for a 75-kilometer segment of the flood-prone Vermilion River located in coastal Louisiana, USA. The Vermilion is a tidal freshwater river affected by baseflow regulation, rapid urbanization, and hydromodification. This river also serves as major freshwater resource for the region. An efficient one-dimensional model calibrated previously for stage and water temperature is used to analyse the salinity impacts due to a large-scale flood control dredging. The analysis is based on 200 alternative scenarios based on combinations of uncertain key forcing variables for a critical 13-day intrusion period. The analysis reveals a nonlinear effect on mean salinities and position of the brackish water limit as a function of uncertain forcing variables. Dredging also increases the variability of salinity encroachment effects due to uncertainty in future forcing conditions (e.g. relative sea level rise, baseflow diversion volumes, and salinities at the river mouth). The robust analysis presented here provides a foundation for future model-based assessments of under-studied tidal freshwater rivers and provides key insights for coastal management and sustainability efforts in general.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"243 - 251"},"PeriodicalIF":2.5,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15715124.2021.1961795","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45897497","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}
Pub Date : 2021-08-17DOI: 10.1080/15715124.2021.1961793
S. Walther, Adriana E. Martinez, B. K. Greenfield
ABSTRACT The impact of large dams primarily built in the 1950s and 1960s has been extensively studied; more recent dam construction often occurs alongside habitat restoration activities, which have the potential to mitigate impacts. Jordanelle Dam on the Provo River, constructed in 1992, is economically and ecologically important to the region. This study aims to elucidate the effects of the dam on the sediment distribution and mobility of the river to inform future management of the system. Due to decreased flows, gravels (D16, D50) downstream of the dam are generally larger and subsurface grains are significantly coarser (p < 0.05), than those upstream of the dam. Further, the flow required to mobilize sediment is larger downstream of the dam and occurs rarely, leading to less mobile sediment and a more stable channel. The reduced mobility of sediment below the dam has decreased channel complexity. Much of the mobile sediment below the dam may be supplied from an unaltered river reach, rather than upstream mobilization. This sediment is vital to trout habitat, an important aspect of the recreation economy of the region. Monitoring changes in grain size distribution below the dam is necessary to prevent the loss of this valuable resource through diminished spawning habitat.
{"title":"Impact of Jordanelle Dam on sedimentological and ecohydrological regimes of the Provo River, Utah, USA","authors":"S. Walther, Adriana E. Martinez, B. K. Greenfield","doi":"10.1080/15715124.2021.1961793","DOIUrl":"https://doi.org/10.1080/15715124.2021.1961793","url":null,"abstract":"ABSTRACT The impact of large dams primarily built in the 1950s and 1960s has been extensively studied; more recent dam construction often occurs alongside habitat restoration activities, which have the potential to mitigate impacts. Jordanelle Dam on the Provo River, constructed in 1992, is economically and ecologically important to the region. This study aims to elucidate the effects of the dam on the sediment distribution and mobility of the river to inform future management of the system. Due to decreased flows, gravels (D16, D50) downstream of the dam are generally larger and subsurface grains are significantly coarser (p < 0.05), than those upstream of the dam. Further, the flow required to mobilize sediment is larger downstream of the dam and occurs rarely, leading to less mobile sediment and a more stable channel. The reduced mobility of sediment below the dam has decreased channel complexity. Much of the mobile sediment below the dam may be supplied from an unaltered river reach, rather than upstream mobilization. This sediment is vital to trout habitat, an important aspect of the recreation economy of the region. Monitoring changes in grain size distribution below the dam is necessary to prevent the loss of this valuable resource through diminished spawning habitat.","PeriodicalId":14344,"journal":{"name":"International Journal of River Basin Management","volume":"21 1","pages":"127 - 137"},"PeriodicalIF":2.5,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42545049","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：