Pub Date : 2021-07-05DOI: 10.1080/24705357.2021.1938259
Daniella Montali-Ashworth, A. Vowles, G. M. D. Almeida, P. Kemp
Anthropogenic infrastructure in rivers (e.g. culverts, dams and weirs) can block the movements of fish and negatively impact their communities. Recent research has shown that fish passage at such b...
{"title":"Understanding fish-hydrodynamic interactions within Cylindrical Bristle Cluster arrays to improve passage over sloped weirs","authors":"Daniella Montali-Ashworth, A. Vowles, G. M. D. Almeida, P. Kemp","doi":"10.1080/24705357.2021.1938259","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938259","url":null,"abstract":"Anthropogenic infrastructure in rivers (e.g. culverts, dams and weirs) can block the movements of fish and negatively impact their communities. Recent research has shown that fish passage at such b...","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91244100","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 : 2021-07-03DOI: 10.1080/24705357.2021.1951506
A. Packman, C. Robinson, N. Lamouroux
The combination of climate change and increasing development of land and water resources is imposing pressure on aquatic ecosystems worldwide (Poff et al. 2007; Blann et al. 2009; Arthington et al. 2010; Best 2019; Boretti and Rosa 2019; Reid et al. 2019). Many drivers of fluvial processes are changing today, and many of these changes are expected to accelerate in the near future. Spatial patterns and timing of precipitation are changing globally, thereby shifting water inputs into freshwater systems and potentially producing more floods and droughts via intensification of the hydrological cycle, increasing frequency of extreme events, and increasing duration of dry seasons (Davis et al. 2015; Madakumbura et al. 2019; Koutsoyiannis 2020). Under increasing pressure from water insecurity, both governmental agencies and private landowners are increasing the abstraction of sourcewaters for human use, thereby moving and storing greater amounts of water throughout fluvial systems (Jaramillo and Destouni 2015; Rodell et al. 2018; Best 2019; Boretti and Rosa 2019). Beyond the well-established effects of dams fragmenting river ecosystems, increased damming of headwaters and large-scale water diversions affect downstream river ecosystems by dewatering rivers, shifting patterns of sediment deposition and aggradation, and reducing habitat heterogeneity (Veldkamp et al. 2017; Sabater et al. 2018; Best 2019). Ongoing land development and industrial agricultural practices are also accelerating soil erosion and export of nutrients from the terrestrial landscape to the aquatic environment (Blann et al. 2009; Seitzinger et al. 2010; Borrelli et al. 2017). Globally, the cumulative effects of these changes are altering continental balances of water (increasing evaporation from the continents to the atmosphere) (Jaramillo and Destouni 2015; Rodell et al. 2018; Zhan et al. 2019), eroding and exporting large amounts of soils and sediments (Borrelli et al. 2017; Best 2019), and greatly increasing the delivery of nutrients from the continents to the oceans (Seitzinger et al. 2010; Beusen et al. 2016; Sinha et al. 2017). Increased information on links between watershed management, river flow, river hydraulics and habitats, and ecosystems is needed to ensure the sustainability of water resources and maintain the integrity of aquatic ecosystems. The knowledge needed to effectively protect and restore river ecosystems has proven difficult to obtain and translate into practice for river management and hydraulic engineering. While many fluvial processes have been studied individually, it is extremely difficult to predict the long-term consequences of simultaneous changes in climate, land use, and river management on aquatic ecosystems. Consequently, there is considerable uncertainty in the long-term outcomes of key processes that structure river ecosystems, such as changing river flow conditions; inputs of sediments, nutrients, and terrestrial organic matter; and the spatiotem
气候变化与土地和水资源的日益开发相结合，正在对全球水生生态系统施加压力(Poff et al. 2007;Blann et al. 2009;Arthington et al. 2010;最好的2019年;Boretti and Rosa 2019;Reid et al. 2019)。今天，河流过程的许多驱动因素正在发生变化，预计其中许多变化将在不久的将来加速。全球降水的空间格局和时间正在发生变化，从而将水输入转移到淡水系统，并可能通过加强水文循环、增加极端事件的频率和增加旱季的持续时间而产生更多的洪水和干旱(Davis et al. 2015;Madakumbura等人，2019;Koutsoyiannis 2020)。在水不安全的压力日益增大的情况下，政府机构和私人土地所有者都在增加对水源的提取，以供人类使用，从而在河流系统中移动和储存更多的水(Jaramillo和Destouni 2015;Rodell et al. 2018;最好的2019年;Boretti和Rosa 2019)。除了水坝对河流生态系统的破坏作用之外，上游水坝的增加和大规模的引水还会通过使河流脱水、改变泥沙沉积和淤积模式以及降低栖息地异质性来影响下游河流生态系统(Veldkamp等人，2017;Sabater et al. 2018;最好的2019)。正在进行的土地开发和工业化农业实践也加速了土壤侵蚀和从陆地景观向水生环境输出营养物质(Blann等人，2009;Seitzinger et al. 2010;Borrelli et al. 2017)。在全球范围内，这些变化的累积效应正在改变大陆的水平衡(增加从大陆到大气的蒸发)(Jaramillo和Destouni 2015;Rodell et al. 2018;Zhan et al. 2019)，侵蚀并输出大量土壤和沉积物(Borrelli et al. 2017;Best 2019)，并大大增加了从大陆到海洋的营养物质的输送(Seitzinger et al. 2010;Beusen et al. 2016;Sinha et al. 2017)。为了确保水资源的可持续性和维持水生生态系统的完整性，需要更多地了解流域管理、河流流量、河流水力学和生境与生态系统之间的联系。事实证明，有效保护和恢复河流生态系统所需的知识很难获得，也很难转化为河流管理和水利工程的实践。虽然对许多河流过程进行了单独的研究，但要预测气候、土地利用和河流管理同时变化对水生生态系统的长期影响是极其困难的。因此，构成河流生态系统的关键过程的长期结果存在相当大的不确定性，例如河流流量条件的变化;沉积物、营养物和陆生有机物的输入;河流与边缘生境连通性的时空分布，包括潜流、河岸和漫滩环境。人们越来越认识到这些生态挑战，以及未来河流系统可能发生的更大变化，这促使人们对保护、恢复和恢复力措施产生了更大的兴趣，以保护河流系统的生物多样性、生态功能和社会效益。每个河流的保护和恢复工作都有广泛的目标。因此，在生物多样性保护、雨水保留、季节性储水和养分管理方面提出了不同的解决方案(Nienhuis和Leuven 2001;Angelopoulos et al. 2017;Roy et al. 2018;Weber et al. 2018)。由于理解当前水生生态系统面临的挑战的复杂性，很难确定单个水生系统内多重保护和恢复努力的长期结果(Friberg et al. 2016;Lorenz et al. 2018)，在将生态反应的关键环境驱动因素信息综合为河流管理的整体措施方面进展甚微(Palmer and Ruhi 2019;Roni 2019)。
{"title":"Hydraulic drivers of populations, communities and ecosystem processes","authors":"A. Packman, C. Robinson, N. Lamouroux","doi":"10.1080/24705357.2021.1951506","DOIUrl":"https://doi.org/10.1080/24705357.2021.1951506","url":null,"abstract":"The combination of climate change and increasing development of land and water resources is imposing pressure on aquatic ecosystems worldwide (Poff et al. 2007; Blann et al. 2009; Arthington et al. 2010; Best 2019; Boretti and Rosa 2019; Reid et al. 2019). Many drivers of fluvial processes are changing today, and many of these changes are expected to accelerate in the near future. Spatial patterns and timing of precipitation are changing globally, thereby shifting water inputs into freshwater systems and potentially producing more floods and droughts via intensification of the hydrological cycle, increasing frequency of extreme events, and increasing duration of dry seasons (Davis et al. 2015; Madakumbura et al. 2019; Koutsoyiannis 2020). Under increasing pressure from water insecurity, both governmental agencies and private landowners are increasing the abstraction of sourcewaters for human use, thereby moving and storing greater amounts of water throughout fluvial systems (Jaramillo and Destouni 2015; Rodell et al. 2018; Best 2019; Boretti and Rosa 2019). Beyond the well-established effects of dams fragmenting river ecosystems, increased damming of headwaters and large-scale water diversions affect downstream river ecosystems by dewatering rivers, shifting patterns of sediment deposition and aggradation, and reducing habitat heterogeneity (Veldkamp et al. 2017; Sabater et al. 2018; Best 2019). Ongoing land development and industrial agricultural practices are also accelerating soil erosion and export of nutrients from the terrestrial landscape to the aquatic environment (Blann et al. 2009; Seitzinger et al. 2010; Borrelli et al. 2017). Globally, the cumulative effects of these changes are altering continental balances of water (increasing evaporation from the continents to the atmosphere) (Jaramillo and Destouni 2015; Rodell et al. 2018; Zhan et al. 2019), eroding and exporting large amounts of soils and sediments (Borrelli et al. 2017; Best 2019), and greatly increasing the delivery of nutrients from the continents to the oceans (Seitzinger et al. 2010; Beusen et al. 2016; Sinha et al. 2017). Increased information on links between watershed management, river flow, river hydraulics and habitats, and ecosystems is needed to ensure the sustainability of water resources and maintain the integrity of aquatic ecosystems. The knowledge needed to effectively protect and restore river ecosystems has proven difficult to obtain and translate into practice for river management and hydraulic engineering. While many fluvial processes have been studied individually, it is extremely difficult to predict the long-term consequences of simultaneous changes in climate, land use, and river management on aquatic ecosystems. Consequently, there is considerable uncertainty in the long-term outcomes of key processes that structure river ecosystems, such as changing river flow conditions; inputs of sediments, nutrients, and terrestrial organic matter; and the spatiotem","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89822307","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 : 2021-07-03DOI: 10.1080/24705357.2021.1938254
G. Burgazzi, P. Vezza, G. Negro, Luca Astegiano, Riccardo Pellicanó, Beatrice Pinna, P. Viaroli, A. Laini
Abstract Habitat modelling aims to predict changes in the structure of aquatic communities as a function of habitat availability. It is a primary tool to inform management actions and to search for the best compromise between biodiversity conservation and water supply. The construction of these models requires in-depth knowledge about the main hydrological and geomorphological drivers that affect local communities. However, these drivers act at different spatial scales and determining which investigation scale is the best trade-off between model accuracy and model transferability is crucial. The present work aims to evaluate the mesoscale for habitat modelling of aquatic macroinvertebrates, by testing the effect of microhabitat (flow velocity, water depth, substrate), mesohabitat (riffles, glides, backwaters, isolated ponds) and spatial position (coordinates and derived spatial variables) on macroinvertebrate community variability. Multivariate spatial analyses were used to analyse the macroinvertebrate data collected in a braided reach of the Trebbia River (N Italy). Mesohabitat was a good predictor of macroinvertebrate community composition, although both microhabitat and space also showed a significant effect. The outcome of this work highlights the transferability of the results across mesohabitats, which supports the use of mesoscale modelling for macroinvertebrate distribution in braided rivers.
{"title":"Effect of microhabitats, mesohabitats and spatial position on macroinvertebrate communities of a braided river","authors":"G. Burgazzi, P. Vezza, G. Negro, Luca Astegiano, Riccardo Pellicanó, Beatrice Pinna, P. Viaroli, A. Laini","doi":"10.1080/24705357.2021.1938254","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938254","url":null,"abstract":"Abstract Habitat modelling aims to predict changes in the structure of aquatic communities as a function of habitat availability. It is a primary tool to inform management actions and to search for the best compromise between biodiversity conservation and water supply. The construction of these models requires in-depth knowledge about the main hydrological and geomorphological drivers that affect local communities. However, these drivers act at different spatial scales and determining which investigation scale is the best trade-off between model accuracy and model transferability is crucial. The present work aims to evaluate the mesoscale for habitat modelling of aquatic macroinvertebrates, by testing the effect of microhabitat (flow velocity, water depth, substrate), mesohabitat (riffles, glides, backwaters, isolated ponds) and spatial position (coordinates and derived spatial variables) on macroinvertebrate community variability. Multivariate spatial analyses were used to analyse the macroinvertebrate data collected in a braided reach of the Trebbia River (N Italy). Mesohabitat was a good predictor of macroinvertebrate community composition, although both microhabitat and space also showed a significant effect. The outcome of this work highlights the transferability of the results across mesohabitats, which supports the use of mesoscale modelling for macroinvertebrate distribution in braided rivers.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77059084","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 : 2021-07-02DOI: 10.1080/24705357.2021.1938258
Vahid Sobhi Gollo, Tabea Broecker, J. Lewandowski, G. Nützmann, R. Hinkelmann
Abstract Tube dwelling of chironomids often dominates benthic communities in freshwater ecosystems with high population density and pumping rates. This strongly enhances exchange across the sediment-water interface and impacts biogeochemical processes. Such processes are investigated by tracking the flow initiated by chironomid’s pumping through and around burrows using laboratory and computer models. We used modeling and experimental results of other authors considering U-shaped burrows embedded in the sediment to improve process-understanding and prove the plausibility of an integral modeling approach. In contrast to coupled models of pipe (burrow), surface water (overlying water column) and groundwater flow (surrounding sediment), we present a novel high-resolution integral formulation for the porous medium-surface water domain (called porousInter as part of OpenFOAM (Open Field Operation and Manipulation)). This approach solves the extended version of the Navier-Stokes equations allowing simultaneous flow simulation in the burrow, the overlying water column and the surrounding sediment to better account for feedback effects between the sediment and surface water. Using similar model setup as of a coupled approach, we performed scenarios of flow through burrow and sediment triggered by pumping in the center of the burrow. Plausible agreement of our integral model with results of a coupled model and experimental results was obtained when comparing flow patterns around the burrows, between two burrow branches and at burrow inlet and outlet.
{"title":"An integral approach to simulate three-dimensional flow in and around a ventilated U-shaped chironomid dwelled burrow","authors":"Vahid Sobhi Gollo, Tabea Broecker, J. Lewandowski, G. Nützmann, R. Hinkelmann","doi":"10.1080/24705357.2021.1938258","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938258","url":null,"abstract":"Abstract Tube dwelling of chironomids often dominates benthic communities in freshwater ecosystems with high population density and pumping rates. This strongly enhances exchange across the sediment-water interface and impacts biogeochemical processes. Such processes are investigated by tracking the flow initiated by chironomid’s pumping through and around burrows using laboratory and computer models. We used modeling and experimental results of other authors considering U-shaped burrows embedded in the sediment to improve process-understanding and prove the plausibility of an integral modeling approach. In contrast to coupled models of pipe (burrow), surface water (overlying water column) and groundwater flow (surrounding sediment), we present a novel high-resolution integral formulation for the porous medium-surface water domain (called porousInter as part of OpenFOAM (Open Field Operation and Manipulation)). This approach solves the extended version of the Navier-Stokes equations allowing simultaneous flow simulation in the burrow, the overlying water column and the surrounding sediment to better account for feedback effects between the sediment and surface water. Using similar model setup as of a coupled approach, we performed scenarios of flow through burrow and sediment triggered by pumping in the center of the burrow. Plausible agreement of our integral model with results of a coupled model and experimental results was obtained when comparing flow patterns around the burrows, between two burrow branches and at burrow inlet and outlet.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87470866","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 : 2021-07-02DOI: 10.1080/24705357.2021.1938256
R. Villanueva, Moritz Thom, J. Visscher, M. Paul, T. Schlurmann
Abstract Seagrasses are essential marine ecosystems for which restoration has proven challenging due to increased hydrodynamic stress. This study aims to analyze the flow alteration induced by an artificial seagrass (ASG) meadow by characterizing its wake effect through a shelter distance and thus yield guidance for seagrass restoration projects. Here, we define shelter distance as the longitudinal extent behind a meadow, with respect to the flow direction, where seagrass is protected and can hence grow successfully. Flume experiments were conducted for submerged meadows with three different lengths at constant canopy height, shoot density and water depth, and three different cross-section-averaged longitudinal flow velocities measured with state-of-the-art Particle Image Velocimetry (PIV). For the tested meadow morphology and hydrodynamic conditions, meadow length played a less important role regarding shelter distance, while incident flow velocity and effective canopy height governed the wake effect. Incident velocities <30 cm s−1 prompted shelter distances >2 m behind the meadow, whereas higher velocities led to a reduced shelter distance ranging from 20-40 cm. ASG additionally produced an upwelling effect on the vertical distribution of the velocity profile observed along the wake, regardless of meadow length and incident velocity. Our results suggest that restoration projects should aim for areas of low flow, where currents induced by tidal or wind waves are less pronounced in order to activate larger shelter distances.
{"title":"Wake length of an artificial seagrass meadow: a study of shelter and its feasibility for restoration","authors":"R. Villanueva, Moritz Thom, J. Visscher, M. Paul, T. Schlurmann","doi":"10.1080/24705357.2021.1938256","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938256","url":null,"abstract":"Abstract Seagrasses are essential marine ecosystems for which restoration has proven challenging due to increased hydrodynamic stress. This study aims to analyze the flow alteration induced by an artificial seagrass (ASG) meadow by characterizing its wake effect through a shelter distance and thus yield guidance for seagrass restoration projects. Here, we define shelter distance as the longitudinal extent behind a meadow, with respect to the flow direction, where seagrass is protected and can hence grow successfully. Flume experiments were conducted for submerged meadows with three different lengths at constant canopy height, shoot density and water depth, and three different cross-section-averaged longitudinal flow velocities measured with state-of-the-art Particle Image Velocimetry (PIV). For the tested meadow morphology and hydrodynamic conditions, meadow length played a less important role regarding shelter distance, while incident flow velocity and effective canopy height governed the wake effect. Incident velocities <30 cm s−1 prompted shelter distances >2 m behind the meadow, whereas higher velocities led to a reduced shelter distance ranging from 20-40 cm. ASG additionally produced an upwelling effect on the vertical distribution of the velocity profile observed along the wake, regardless of meadow length and incident velocity. Our results suggest that restoration projects should aim for areas of low flow, where currents induced by tidal or wind waves are less pronounced in order to activate larger shelter distances.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85228640","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 : 2021-07-02DOI: 10.1080/24705357.2021.1938252
M. Paul, N. Kerpen
Abstract The inclusion of coastal ecosystems in coastal protection strategies is highly desired, but for temperate regions it is hampered by uncertainty about the provision of relevant ecosystem services over the annual growth cycle. This flume study compared winter stages of the two salt marsh species Spartina anglica and Elymus athericus with and without above ground biomass to bare soil to assess their protection service against vertical bed erosion in the surf and swash zone. Results yielded no effect of the above ground biomass on mean erosion, even though the species responded differently with E. athericus buckling and S. anglica withstanding the hydrodynamic forcing. Equally, no significant differences were observed between species which is attributed to the comparable dry root biomass and soil bulk density of the used vegetated patches. While this similarity does not allow for establishment of quantitative relationships, the results suggest a species independent erosion protection efficiency persisting throughout the year. This has the potential to simplify the consideration of erosion protection by salt marsh in coastal protection strategies, as it alleviates the need for detailed differentiation on species or seasonal level of this ecosystem service.
{"title":"Erosion protection by winter state of salt marsh vegetation","authors":"M. Paul, N. Kerpen","doi":"10.1080/24705357.2021.1938252","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938252","url":null,"abstract":"Abstract The inclusion of coastal ecosystems in coastal protection strategies is highly desired, but for temperate regions it is hampered by uncertainty about the provision of relevant ecosystem services over the annual growth cycle. This flume study compared winter stages of the two salt marsh species Spartina anglica and Elymus athericus with and without above ground biomass to bare soil to assess their protection service against vertical bed erosion in the surf and swash zone. Results yielded no effect of the above ground biomass on mean erosion, even though the species responded differently with E. athericus buckling and S. anglica withstanding the hydrodynamic forcing. Equally, no significant differences were observed between species which is attributed to the comparable dry root biomass and soil bulk density of the used vegetated patches. While this similarity does not allow for establishment of quantitative relationships, the results suggest a species independent erosion protection efficiency persisting throughout the year. This has the potential to simplify the consideration of erosion protection by salt marsh in coastal protection strategies, as it alleviates the need for detailed differentiation on species or seasonal level of this ecosystem service.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89341669","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 : 2021-07-02DOI: 10.1080/24705357.2021.1938253
M. Taphorn, Raúl Villanueva, Maike Paul, Jan Visscher, Torsten Schlurmann
Abstract Seagrass surrogates are commonly used to mimic the behaviour of seagrasses exposed to currents and their effects on flow fields. The interaction is highly dependent on the chosen mechanic and geometric properties of the surrogates and needs to be understood in order to design artificial meadows. The interaction of single surrogates in unidirectional flow fields is studied by means of physical modelling. Surrogates made of plastic materials with different flexural rigidities, buoyancies and geometries are exposed to varying flow velocities. The instantaneous velocity fields in the vicinity and wake of the surrogates are measured by stereoscopic Particle Image Velocimetry (PIV). All employed surrogates disrupt and interact with the flow field by changing their posture. An empirical relation is derived between the flexural rigidity, buoyancy and characteristic diameter of the surrogates and the imposed differences in the attenuation ratio of flow velocities. Further, the approaching flow velocity and distance behind the surrogate influence the estimated attenuation. The vortex shedding frequency imposed by artificial seagrass is lower than frequencies determined for infinite, rigid cylindrical structures. Three main characterizing properties: the modulus of elasticity, buoyancy and cross-sectional dimensions need to be taken into account for design of artificial seagrass meadows. Our findings advance knowledge of fluid-structure interactions of flexible materials and help to progress proper design of artificial seagrass meadows.
{"title":"Flow field and wake structure characteristics imposed by single seagrass blade surrogates","authors":"M. Taphorn, Raúl Villanueva, Maike Paul, Jan Visscher, Torsten Schlurmann","doi":"10.1080/24705357.2021.1938253","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938253","url":null,"abstract":"Abstract Seagrass surrogates are commonly used to mimic the behaviour of seagrasses exposed to currents and their effects on flow fields. The interaction is highly dependent on the chosen mechanic and geometric properties of the surrogates and needs to be understood in order to design artificial meadows. The interaction of single surrogates in unidirectional flow fields is studied by means of physical modelling. Surrogates made of plastic materials with different flexural rigidities, buoyancies and geometries are exposed to varying flow velocities. The instantaneous velocity fields in the vicinity and wake of the surrogates are measured by stereoscopic Particle Image Velocimetry (PIV). All employed surrogates disrupt and interact with the flow field by changing their posture. An empirical relation is derived between the flexural rigidity, buoyancy and characteristic diameter of the surrogates and the imposed differences in the attenuation ratio of flow velocities. Further, the approaching flow velocity and distance behind the surrogate influence the estimated attenuation. The vortex shedding frequency imposed by artificial seagrass is lower than frequencies determined for infinite, rigid cylindrical structures. Three main characterizing properties: the modulus of elasticity, buoyancy and cross-sectional dimensions need to be taken into account for design of artificial seagrass meadows. Our findings advance knowledge of fluid-structure interactions of flexible materials and help to progress proper design of artificial seagrass meadows.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91350686","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 : 2021-06-30DOI: 10.1080/24705357.2021.1938251
Bernhard Wegscheider, T. Linnansaari, Mouhamed Ndong, K. Haralampides, A. St‐Hilaire, M. Schneider, R. Curry
Physical habitat models represent a widely used tool in river management, yet, there is a growing consensus—particularly for large rivers—that fundamental principles have limits, and it is evident ...
{"title":"Fish habitat modelling in large rivers: combining expert opinion and hydrodynamic modelling to inform river management","authors":"Bernhard Wegscheider, T. Linnansaari, Mouhamed Ndong, K. Haralampides, A. St‐Hilaire, M. Schneider, R. Curry","doi":"10.1080/24705357.2021.1938251","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938251","url":null,"abstract":"Physical habitat models represent a widely used tool in river management, yet, there is a growing consensus—particularly for large rivers—that fundamental principles have limits, and it is evident ...","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73600594","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 : 2021-06-29DOI: 10.1080/24705357.2021.1938255
G. Lama, A. Errico, V. Pasquino, S. Mirzaei, F. Preti, G. Chirico
Abstract One of the main purposes of Ecohydraulics is to predict the effects of riparian vegetation on aquatic ecosystems within real water channels. The interaction between water flow and riparian plants significantly affects flow dynamics, hydraulic conveyance, and water quality of vegetated water bodies. This study aimed at quantifying analytically the uncertainty in flow average velocity estimations associated with the uncertainty of Leaf Area Index (LAI) of Phragmites australis (Cav.) Trin. ex Steudel covering a vegetated channel. The impacts of this species on the hydrodynamics of vegetated streams are far to be completely understood. The uncertainty in flow average velocity was assessed through the first-order second-moment statistical method, by comparing direct and indirect LAI measurements of mature Phragmites australis plants. Indirect LAI values were obtained using the LICOR® LAI-2000 Plant Canopy Analyzer device. The results of this study suggest that the uncertainties in flow average velocity estimations are comparable to those associated with experimental measurements of streamwise velocity components retrieved in real vegetated flows fully covered by mature Phragmites australis plants.
{"title":"Velocity uncertainty quantification based on Riparian vegetation indices in open channels colonized by Phragmites australis","authors":"G. Lama, A. Errico, V. Pasquino, S. Mirzaei, F. Preti, G. Chirico","doi":"10.1080/24705357.2021.1938255","DOIUrl":"https://doi.org/10.1080/24705357.2021.1938255","url":null,"abstract":"Abstract One of the main purposes of Ecohydraulics is to predict the effects of riparian vegetation on aquatic ecosystems within real water channels. The interaction between water flow and riparian plants significantly affects flow dynamics, hydraulic conveyance, and water quality of vegetated water bodies. This study aimed at quantifying analytically the uncertainty in flow average velocity estimations associated with the uncertainty of Leaf Area Index (LAI) of Phragmites australis (Cav.) Trin. ex Steudel covering a vegetated channel. The impacts of this species on the hydrodynamics of vegetated streams are far to be completely understood. The uncertainty in flow average velocity was assessed through the first-order second-moment statistical method, by comparing direct and indirect LAI measurements of mature Phragmites australis plants. Indirect LAI values were obtained using the LICOR® LAI-2000 Plant Canopy Analyzer device. The results of this study suggest that the uncertainties in flow average velocity estimations are comparable to those associated with experimental measurements of streamwise velocity components retrieved in real vegetated flows fully covered by mature Phragmites australis plants.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75700798","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 : 2021-06-15DOI: 10.1080/24705357.2020.1871307
D. Courret, P. Baran, M. Larinier
Abstract Hydropeaking by hydroelectric facilities generates sudden changes in river flows and can affect the composition, abundance and structure of fish and invertebrate populations over long distances. To assess the level of hydrological alteration, as a factor of risk of biological impacts, a synthetic indicator was developed. Based on the analysis of 97 hydrometric stations and 1575 years of unaltered flow data, rates of change in flow were calculated. Formulas representing the fastest natural variations, depending on the mean stream flow, the type of variation (increase or decrease) and the range of variation were established. Based on the analysis of 80 hydrometric stations and 491 years of flow data affected by hydropeaking, a method was developed to identify hydropeaks, essentially defined as variations with a rate of change greater than the maximum natural value computed using the formulas. A synthetic indicator differentiating five levels of hydrological alteration was developed using linear discriminant analysis based on five parameters characterizing hydropeaking regimes. Examples show that this indicator is sensitive to changes in the management of hydroelectric facilities and provides information on the spatial and temporal evolutions in hydropeaking regimes, including the progressive attenuation during downstream propagation.
{"title":"An indicator to characterize hydrological alteration due to hydropeaking","authors":"D. Courret, P. Baran, M. Larinier","doi":"10.1080/24705357.2020.1871307","DOIUrl":"https://doi.org/10.1080/24705357.2020.1871307","url":null,"abstract":"Abstract Hydropeaking by hydroelectric facilities generates sudden changes in river flows and can affect the composition, abundance and structure of fish and invertebrate populations over long distances. To assess the level of hydrological alteration, as a factor of risk of biological impacts, a synthetic indicator was developed. Based on the analysis of 97 hydrometric stations and 1575 years of unaltered flow data, rates of change in flow were calculated. Formulas representing the fastest natural variations, depending on the mean stream flow, the type of variation (increase or decrease) and the range of variation were established. Based on the analysis of 80 hydrometric stations and 491 years of flow data affected by hydropeaking, a method was developed to identify hydropeaks, essentially defined as variations with a rate of change greater than the maximum natural value computed using the formulas. A synthetic indicator differentiating five levels of hydrological alteration was developed using linear discriminant analysis based on five parameters characterizing hydropeaking regimes. Examples show that this indicator is sensitive to changes in the management of hydroelectric facilities and provides information on the spatial and temporal evolutions in hydropeaking regimes, including the progressive attenuation during downstream propagation.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85697737","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}
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