Pub Date : 2019-01-02DOI: 10.1080/24705357.2019.1646616
T. Marsden, I. Stuart
Abstract In tropical coastal lowland rivers, there are frequently biodiverse upstream migrations of post-larval and juvenile diadromous fish from estuaries into freshwater. Tidal barriers completely block major migratory pathways for these fish and have contributed to major losses of freshwater biodiversity. In northern Australia, early efforts to improve tropical river fish passage with salmonid-style fishways completely failed. Since the mid-1990s, low gradient vertical-slot and rock fishways improved fish passage but the smallest and most abundant fish (i.e. from 10 to 100 mm long) often still failed to ascend. Since the mid-2000s, there was a paradigm shift in hydraulic design criteria for new fishways, with a renewed focus on: (i) low turbulence, (ii) maximized roughness and hydraulic boundary layers to optimise fish ascent. We used a combined methodology, firstly developing a conceptual model of fish movement to inform fishway design criteria, secondly tabulating past and present fishway design criteria, and thirdly conducting a series of brief field case-studies, at tidal barriers in tropical rivers for new technical and rock fishways. Our objective was to evaluate the success of these new designs for passage of very small (from 9 mm long) diadromous fish on low head barriers (i.e. <3 m high). We conclude that while there have been improvements in passage of small-bodied fish at tidal barriers further experimental work is still needed to test and refine current ecohydraulic fishway design criteria.
{"title":"Fish passage developments for small-bodied tropical fish: field case-studies lead to technology improvements","authors":"T. Marsden, I. Stuart","doi":"10.1080/24705357.2019.1646616","DOIUrl":"https://doi.org/10.1080/24705357.2019.1646616","url":null,"abstract":"Abstract In tropical coastal lowland rivers, there are frequently biodiverse upstream migrations of post-larval and juvenile diadromous fish from estuaries into freshwater. Tidal barriers completely block major migratory pathways for these fish and have contributed to major losses of freshwater biodiversity. In northern Australia, early efforts to improve tropical river fish passage with salmonid-style fishways completely failed. Since the mid-1990s, low gradient vertical-slot and rock fishways improved fish passage but the smallest and most abundant fish (i.e. from 10 to 100 mm long) often still failed to ascend. Since the mid-2000s, there was a paradigm shift in hydraulic design criteria for new fishways, with a renewed focus on: (i) low turbulence, (ii) maximized roughness and hydraulic boundary layers to optimise fish ascent. We used a combined methodology, firstly developing a conceptual model of fish movement to inform fishway design criteria, secondly tabulating past and present fishway design criteria, and thirdly conducting a series of brief field case-studies, at tidal barriers in tropical rivers for new technical and rock fishways. Our objective was to evaluate the success of these new designs for passage of very small (from 9 mm long) diadromous fish on low head barriers (i.e. <3 m high). We conclude that while there have been improvements in passage of small-bodied fish at tidal barriers further experimental work is still needed to test and refine current ecohydraulic fishway design criteria.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"116 1","pages":"14 - 26"},"PeriodicalIF":0.0,"publicationDate":"2019-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87815992","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 : 2018-07-03DOI: 10.1080/24705357.2018.1555777
A. Vowles, P. Karageorgopoulos, P. Kemp
ABSTARCT Culverts used to convey river water under roads and embankments are one of the most common small-scale barriers to longitudinal fish movements worldwide. Using an open channel flume, this study assessed the ability of upstream migrating adult river lamprey (Lampetra fluviatilis) to ascend a pipe culvert when unmodified (control [C]) and retrofitted with spoiler baffles (treatment [T]) under three flow regimes (low discharge [L], high discharge [H] and high discharge with a raised downstream water level [HD]). Few lamprey attempted to ascend the culvert under low (11%) and high (21%) discharge in both the control and the treatments. Despite a greater percentage attempting to pass (75%) under HD, they frequently failed. Contrary to our predictions, upstream progress was impeded by the spoiler baffles and may reflect low motivation or avoidance of the physical and/or hydraulic conditions encountered. This study emphasizes the need to better understand the factors influencing the behaviour and motivation of fish as they ascend fish passage structures, and of the importance of reporting negative results as fish passage solutions that are promising for some species may be ineffective for others.
{"title":"Upstream movement of river lamprey through a culvert retrofitted with spoiler baffles under experimental conditions","authors":"A. Vowles, P. Karageorgopoulos, P. Kemp","doi":"10.1080/24705357.2018.1555777","DOIUrl":"https://doi.org/10.1080/24705357.2018.1555777","url":null,"abstract":"ABSTARCT Culverts used to convey river water under roads and embankments are one of the most common small-scale barriers to longitudinal fish movements worldwide. Using an open channel flume, this study assessed the ability of upstream migrating adult river lamprey (Lampetra fluviatilis) to ascend a pipe culvert when unmodified (control [C]) and retrofitted with spoiler baffles (treatment [T]) under three flow regimes (low discharge [L], high discharge [H] and high discharge with a raised downstream water level [HD]). Few lamprey attempted to ascend the culvert under low (11%) and high (21%) discharge in both the control and the treatments. Despite a greater percentage attempting to pass (75%) under HD, they frequently failed. Contrary to our predictions, upstream progress was impeded by the spoiler baffles and may reflect low motivation or avoidance of the physical and/or hydraulic conditions encountered. This study emphasizes the need to better understand the factors influencing the behaviour and motivation of fish as they ascend fish passage structures, and of the importance of reporting negative results as fish passage solutions that are promising for some species may be ineffective for others.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"54 1","pages":"107 - 99"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80162235","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 : 2018-07-03DOI: 10.1080/24705357.2018.1535260
J. Lancaster
Abstract In ecohydraulics research, both physical and biological variables must be sampled at scales that are appropriate to the questions being addressed. This essay focuses on ecological topics that may be addressed in the context of ecohydraulics and the scales appropriate for their investigation. The first sections discuss definitions of scale, how environmental heterogeneity influences experimental and sampling designs, and the importance of recognizing that physical and ecological heterogeneity are not necessarily related. Thus, the scales appropriate for a particular research problem should be determined primarily by the ecological phenomenon of interest, plus the generation time and life-space of the study organisms. Studies over the large scales relevant to population and community ecology are logistically difficult and numerical models, but not scaled physical models, may facilitate extrapolations between scales for ecological phenomena. Three examples illustrate how complementary sets of studies executed at different scales can collectively contribute to ecological research problems in an ecohydraulics context. Two examples have strong roots in ecology (population dynamics in disturbed environments; ecosystem engineers) and the third arises from a need to solve applied problems (fish passage). These are topical areas of research to which ecohydraulics could make significant contributions.
{"title":"What is the right scale? Encouraging fruitful engagement for ecology with ecohydraulics","authors":"J. Lancaster","doi":"10.1080/24705357.2018.1535260","DOIUrl":"https://doi.org/10.1080/24705357.2018.1535260","url":null,"abstract":"Abstract In ecohydraulics research, both physical and biological variables must be sampled at scales that are appropriate to the questions being addressed. This essay focuses on ecological topics that may be addressed in the context of ecohydraulics and the scales appropriate for their investigation. The first sections discuss definitions of scale, how environmental heterogeneity influences experimental and sampling designs, and the importance of recognizing that physical and ecological heterogeneity are not necessarily related. Thus, the scales appropriate for a particular research problem should be determined primarily by the ecological phenomenon of interest, plus the generation time and life-space of the study organisms. Studies over the large scales relevant to population and community ecology are logistically difficult and numerical models, but not scaled physical models, may facilitate extrapolations between scales for ecological phenomena. Three examples illustrate how complementary sets of studies executed at different scales can collectively contribute to ecological research problems in an ecohydraulics context. Two examples have strong roots in ecology (population dynamics in disturbed environments; ecosystem engineers) and the third arises from a need to solve applied problems (fish passage). These are topical areas of research to which ecohydraulics could make significant contributions.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"107 1","pages":"63 - 76"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77422511","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 : 2018-07-03DOI: 10.1080/24705357.2019.1619990
Recognition that monitoring the effectiveness of fish passes has tended to use non-standardized methods that make it difficult to directly compare between sites and structures on which generalized conclusions, e.g. using meta-analyses, can be formed has led to current efforts to develop a European Standard guidance document (currently a draft) for assessing fish passage efficiency. It is argued that only systematic, reproducible monitoring studies assessing the performance of fish passes will enable us to improve and develop current fish pass design. Despite describing the need for a multi-method approach, e.g. involving traps, observation, and laboratory studies, the focus of the draft standard is solely directed towards telemetry, a bias that is clear in other recent publications (e.g. Silva et al. 2018). While telemetry (e.g. acoustic, radio, and PIT tagging techniques) undoubtedly has an important role to play as part of a suite of methods that may be employed by researchers to better understand the key factors that influence fish passage efficiency, reliance only on this tool is problematic for a number of reasons. First, telemetry studies often provide valuable information, but are frequently constrained by the sitespecific context on which the case studies are based at the time they are conducted. Second, in situ field studies are unable to control for multiple confounding variables that have the potential to influence results on which conclusions are based. Third, even the most high tech and fine-scale telemetry techniques available are unable to obtain the detailed information on fish behaviour that may be achieved through direct observation. Fourth, telemetry is unsuitable for small bodied adult fish or juveniles of many species, a critical limitation in many understudied regions, such as in the temperate South (e.g. Chile and New Zealand; see Knapp et al. 2019 in a future issue of the Journal of Ecohydraulics). Finally, despite the high standard of current surgical techniques used by those proficient in telemetry, there remains the potential for tag effects that may influence behavioural and other responses (e.g. Jadot et al. 2005; Thorstad et al. 2013). Thus, in contradiction to statements made in the draft standard document, telemetry may have disadvantages, as well as “major advantages”, when compared to the other methods available, and is not the only means by which efficiency estimates can be formed as implied. Laboratory studies enable a variety of observation methods to be used (Knapp et al. 2019), ranging from tracking of fish trajectories to visualisation of flow patterns using techniques such as Particle Imaging Velocimetry (PIV) that are difficult to apply in the field (but see Biggs et al. 2019 in a future issue of the Journal of Ecohydraulics). In the current issue, Vowles et al. (2019) use a large open channel flume to assess the potential for spoiler baffles to improve passage of upstream migrating adult river lamprey (L
认识到监测鱼类通道的有效性倾向于使用非标准化方法，这使得难以直接比较可以形成一般性结论的地点和结构，例如使用元分析，这导致目前努力制定评估鱼类通道效率的欧洲标准指导文件(目前是草案)。有人认为，只有系统的、可重复的监测研究才能评估鱼道的性能，使我们能够改进和发展目前的鱼道设计。尽管描述了多方法方法的必要性，例如涉及陷阱、观察和实验室研究，但标准草案的重点仅针对遥测，这在其他最近的出版物中是明显的偏见(例如Silva等人，2018)。虽然遥测技术(如声学、无线电和PIT标记技术)作为研究人员可以更好地了解影响鱼类通道效率的关键因素的一套方法的一部分，无疑发挥着重要作用，但由于许多原因，仅依赖这种工具是有问题的。首先，遥测研究通常提供有价值的信息，但经常受到案例研究进行时所依据的特定地点背景的限制。第二，现场研究无法控制可能影响结论所依据的结果的多个混杂变量。第三，即使是现有的最高科技和最精细的遥测技术也无法获得通过直接观察可以获得的关于鱼类行为的详细信息。第四，遥测技术不适用于小体成鱼或许多物种的幼鱼，这在许多研究不足的地区是一个严重的限制，例如在温带南部(如智利和新西兰;参见Knapp等人2019年在未来的《生态水力学杂志》上发表的文章)。最后，尽管精通遥测技术的人目前使用的手术技术标准很高，但仍然存在可能影响行为和其他反应的标签效应(例如Jadot等人，2005;Thorstad et al. 2013)。因此，与标准文件草案中所作的陈述相矛盾的是，与其他可用的方法相比，遥测技术可能有缺点，也可能有“主要优点”，而且并不是可以按照暗示的那样形成效率估计的唯一手段。实验室研究可以使用各种观察方法(Knapp等人，2019)，从跟踪鱼类轨迹到使用颗粒成像测速(PIV)等技术可视化流动模式，这些技术难以在现场应用(但请参阅Biggs等人，2019在未来一期的《生态水力学杂志》中)。在本期杂志中，Vowles等人(2019)使用一个大型明渠水槽来评估扰流挡板改善上游迁移的成年河七鳃鳗(Lampetra fluviatilis)通过全尺寸涵洞的潜力。本研究采用经典的操纵实验方法，在控制混杂变量的同时，利用录像技术对鱼对兴趣因素的操纵所表现出的精细行为进行量化。通过对精细尺度行为的观察，我们不仅深入了解了为什么鱼会通过，而且在这种情况下，为什么它们可能无法像预测的那样表现，强调了发表研究的重要性，这些研究既有消极的发现，也有积极的发现。当单独使用遥测技术时，确定支持所获得结果的机制并不总是可能的。这并不意味着实验没有缺点。这些研究代表了对现实的简化，这一问题往往因相对于主题物种大小的领域所施加的空间限制而加剧(Rice et al. 2010)。尽管在这类研究中，鱼通常不会被贴上标签(如果有的话，我们会增加一个进一步的混淆变量)，就像遥测的情况一样，鱼的捕获和处理可能会影响各种指标，包括行为或游泳表现的测量。这种影响也将适用于其他方法，如诱捕和标记-再捕获技术。对鱼类或其他水生动物的观察当然是生态水力学研究的一部分;另一种是物理观察。实验室或现场物理变量的数据收集也采用多种方法，也有不同的优缺点。在选择生物和物理观察方法时，必须彻底检查它们的局限性和兼容性。例如，平均速度测量可能不足以阐明基于鱼道中鱼的详细运动观察的鱼的行为，这可能取决于流动湍流。
{"title":"The importance of a holistic ecohydraulics approach in advancing fish passage design","authors":"","doi":"10.1080/24705357.2019.1619990","DOIUrl":"https://doi.org/10.1080/24705357.2019.1619990","url":null,"abstract":"Recognition that monitoring the effectiveness of fish passes has tended to use non-standardized methods that make it difficult to directly compare between sites and structures on which generalized conclusions, e.g. using meta-analyses, can be formed has led to current efforts to develop a European Standard guidance document (currently a draft) for assessing fish passage efficiency. It is argued that only systematic, reproducible monitoring studies assessing the performance of fish passes will enable us to improve and develop current fish pass design. Despite describing the need for a multi-method approach, e.g. involving traps, observation, and laboratory studies, the focus of the draft standard is solely directed towards telemetry, a bias that is clear in other recent publications (e.g. Silva et al. 2018). While telemetry (e.g. acoustic, radio, and PIT tagging techniques) undoubtedly has an important role to play as part of a suite of methods that may be employed by researchers to better understand the key factors that influence fish passage efficiency, reliance only on this tool is problematic for a number of reasons. First, telemetry studies often provide valuable information, but are frequently constrained by the sitespecific context on which the case studies are based at the time they are conducted. Second, in situ field studies are unable to control for multiple confounding variables that have the potential to influence results on which conclusions are based. Third, even the most high tech and fine-scale telemetry techniques available are unable to obtain the detailed information on fish behaviour that may be achieved through direct observation. Fourth, telemetry is unsuitable for small bodied adult fish or juveniles of many species, a critical limitation in many understudied regions, such as in the temperate South (e.g. Chile and New Zealand; see Knapp et al. 2019 in a future issue of the Journal of Ecohydraulics). Finally, despite the high standard of current surgical techniques used by those proficient in telemetry, there remains the potential for tag effects that may influence behavioural and other responses (e.g. Jadot et al. 2005; Thorstad et al. 2013). Thus, in contradiction to statements made in the draft standard document, telemetry may have disadvantages, as well as “major advantages”, when compared to the other methods available, and is not the only means by which efficiency estimates can be formed as implied. Laboratory studies enable a variety of observation methods to be used (Knapp et al. 2019), ranging from tracking of fish trajectories to visualisation of flow patterns using techniques such as Particle Imaging Velocimetry (PIV) that are difficult to apply in the field (but see Biggs et al. 2019 in a future issue of the Journal of Ecohydraulics). In the current issue, Vowles et al. (2019) use a large open channel flume to assess the potential for spoiler baffles to improve passage of upstream migrating adult river lamprey (L","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"35 1","pages":"61 - 62"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82578236","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 : 2018-07-03DOI: 10.1080/24705357.2019.1576021
Severin Stähly, W. Gostner, M. Franca, C. Robinson, A. Schleiss
Abstract The geometry and hydrodynamics of river reaches are key ecohydraulic descriptors. Statistics of water depth and velocity measurements are usually taken as proxies for habitat suitability in rivers. However, little is known about the sufficiency of data to produce effective and representative results. In this research, 19 reaches with differences in terms of discharge, river width, substrate, reach length, cross-section spacing and geomorphology are investigated. Measurements of flow depth and velocity were taken at multiple, equally spaced cross-sections along each reach. Data were sub-sampled using different methodologies and analysed each time. The sets of sub-sampled data were then compared with those calculated with the full data set from a reach. The focus was put towards the hydro-morphological index of diversity (HMID), a combination of the classical ecohydraulic variables flow depth and velocity. It represents the spatial variability of hydraulic habitats in a reach. The results point out that, with a well-defined sampling strategy, 100 measurement points lead to a good estimation of the HMID value in a reach, if more than eight measurement points are taken per cross-section. For geomorphologies with small complexity or when the analysis only includes the estimation of mean flow depth or mean flow velocity, this number can be decreased according to the results presented here. These findings help both, aquatic ecologists and engineers to estimate their data reliability for hydraulic field measurements in a river reach and are herein discussed taking into account the different studied morphologies.
{"title":"Sampling sufficiency for determining hydraulic habitat diversity","authors":"Severin Stähly, W. Gostner, M. Franca, C. Robinson, A. Schleiss","doi":"10.1080/24705357.2019.1576021","DOIUrl":"https://doi.org/10.1080/24705357.2019.1576021","url":null,"abstract":"Abstract The geometry and hydrodynamics of river reaches are key ecohydraulic descriptors. Statistics of water depth and velocity measurements are usually taken as proxies for habitat suitability in rivers. However, little is known about the sufficiency of data to produce effective and representative results. In this research, 19 reaches with differences in terms of discharge, river width, substrate, reach length, cross-section spacing and geomorphology are investigated. Measurements of flow depth and velocity were taken at multiple, equally spaced cross-sections along each reach. Data were sub-sampled using different methodologies and analysed each time. The sets of sub-sampled data were then compared with those calculated with the full data set from a reach. The focus was put towards the hydro-morphological index of diversity (HMID), a combination of the classical ecohydraulic variables flow depth and velocity. It represents the spatial variability of hydraulic habitats in a reach. The results point out that, with a well-defined sampling strategy, 100 measurement points lead to a good estimation of the HMID value in a reach, if more than eight measurement points are taken per cross-section. For geomorphologies with small complexity or when the analysis only includes the estimation of mean flow depth or mean flow velocity, this number can be decreased according to the results presented here. These findings help both, aquatic ecologists and engineers to estimate their data reliability for hydraulic field measurements in a river reach and are herein discussed taking into account the different studied morphologies.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"9 1","pages":"130 - 144"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84319047","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 : 2018-07-03DOI: 10.1080/24705357.2019.1573648
R. Boothroyd, R. Hardy, J. Warburton, T. Marjoribanks
Abstract In a series of high resolution numerical modelling experiments, we incorporated submerged riparian plants into a computational fluid dynamics (CFD) model used to predict flow structures and drag in river flow. Individual plant point clouds were captured using terrestrial laser scanning (TLS) and geometric characteristics quantified. In the first experiment, flow is modelled around three different plant specimens of the same species (Prunus laurocerasus). In the second experiment, the orientation of another specimen is incrementally rotated to modify the flow-facing structure when foliated and defoliated. Each plant introduces a unique disturbance pattern to the normalized downstream velocity field, resulting in spatially heterogeneous and irregularly shaped velocity profiles. The results question the extent to which generalized velocity profiles can be quantified for morphologically complex plants. Incremental changes in plant orientation introduce gradual changes to the downstream velocity field and cause a substantial range in the quantified drag response. Form drag forces are up to an order of magnitude greater for foliated plants compared to defoliated plants, although the mean drag coefficient for defoliated plants is higher (1.52 defoliated; 1.03 foliated). Variation in the drag coefficients is greatest when the plant is defoliated (up to ∼210% variation when defoliated, ∼80% when foliated).
{"title":"The importance of riparian plant orientation in river flow: implications for flow structures and drag","authors":"R. Boothroyd, R. Hardy, J. Warburton, T. Marjoribanks","doi":"10.1080/24705357.2019.1573648","DOIUrl":"https://doi.org/10.1080/24705357.2019.1573648","url":null,"abstract":"Abstract In a series of high resolution numerical modelling experiments, we incorporated submerged riparian plants into a computational fluid dynamics (CFD) model used to predict flow structures and drag in river flow. Individual plant point clouds were captured using terrestrial laser scanning (TLS) and geometric characteristics quantified. In the first experiment, flow is modelled around three different plant specimens of the same species (Prunus laurocerasus). In the second experiment, the orientation of another specimen is incrementally rotated to modify the flow-facing structure when foliated and defoliated. Each plant introduces a unique disturbance pattern to the normalized downstream velocity field, resulting in spatially heterogeneous and irregularly shaped velocity profiles. The results question the extent to which generalized velocity profiles can be quantified for morphologically complex plants. Incremental changes in plant orientation introduce gradual changes to the downstream velocity field and cause a substantial range in the quantified drag response. Form drag forces are up to an order of magnitude greater for foliated plants compared to defoliated plants, although the mean drag coefficient for defoliated plants is higher (1.52 defoliated; 1.03 foliated). Variation in the drag coefficients is greatest when the plant is defoliated (up to ∼210% variation when defoliated, ∼80% when foliated).","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"73 1","pages":"108 - 129"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79160183","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 : 2018-07-03DOI: 10.1080/24705357.2018.1457987
Aisha Mhashhash, B. Bockelmann-Evans, S. Pan
Abstract Cohesive sediment flocculates under particular circumstances, for example, the increase of salinity in the brackish zone of rivers, forming flocs that are larger and less dense than individual particles. The phenomenon of flocculation plays a significant role in the sediment transport processes of settling, deposition and erosion. This study used an extensive experimental setup using a particle image velocimetry (PIV) camera system to establish a new settling velocity equation as a function of salinity (S) and turbulence (TS). The results were compared with those of studies previously conducted at various estuaries. The experimental research was carried out in a 1 L glass beaker using suspended sediment samples from the Severn Estuary in the United Kingdom. A PIV system and an image processing routine were used to measure floc size distribution (FSD) and settling velocity. Based on the experimental data, Minitab was used to derive a new regression equation to predict the settling velocity.
{"title":"A new settling velocity equation for cohesive sediment based on experimental analysis","authors":"Aisha Mhashhash, B. Bockelmann-Evans, S. Pan","doi":"10.1080/24705357.2018.1457987","DOIUrl":"https://doi.org/10.1080/24705357.2018.1457987","url":null,"abstract":"Abstract Cohesive sediment flocculates under particular circumstances, for example, the increase of salinity in the brackish zone of rivers, forming flocs that are larger and less dense than individual particles. The phenomenon of flocculation plays a significant role in the sediment transport processes of settling, deposition and erosion. This study used an extensive experimental setup using a particle image velocimetry (PIV) camera system to establish a new settling velocity equation as a function of salinity (S) and turbulence (TS). The results were compared with those of studies previously conducted at various estuaries. The experimental research was carried out in a 1 L glass beaker using suspended sediment samples from the Severn Estuary in the United Kingdom. A PIV system and an image processing routine were used to measure floc size distribution (FSD) and settling velocity. Based on the experimental data, Minitab was used to derive a new regression equation to predict the settling velocity.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"73 1","pages":"77 - 85"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79663404","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 : 2018-07-03DOI: 10.1080/24705357.2018.1521709
S. Müller, Olivier Cleynen, S. Hoerner, Nils Lichtenberg, D. Thévenin
Abstract The characteristics of a vortex power plant integrated in a weir have been investigated using computational fluid dynamics, with a special focus on all flow properties relevant to fish migration and energy conversion. The numerical model relies on a Reynolds-averaged, unsteady description using the volume-of-fluid method to describe the free surface. Several monitors are implemented, quantifying, in particular, the distribution of water velocities within the plant, and the probability of impact between drifting objects and turbine blades. Parameters, such as volume flow rate, turbine clearance, turbine speed and number of turbine blades have been varied. The systematic observation of the distribution of velocities and power density help assess the ecological impact of those modifications. It is found that a moderate increase of the turbine clearance and a reduction of the number of blades provide an attractive compromise between power output and opportunity for easy migration. Finally, it is predicted that the hazard associated with a fish hitting turbine blades can be greatly reduced by a careful adaptation of the turbine rotation velocity. Those developments are a first step towards a systematic numerical assessment of the fish-friendliness of machines operating under stringent ecological regulations.
{"title":"Numerical analysis of the compromise between power output and fish-friendliness in a vortex power plant","authors":"S. Müller, Olivier Cleynen, S. Hoerner, Nils Lichtenberg, D. Thévenin","doi":"10.1080/24705357.2018.1521709","DOIUrl":"https://doi.org/10.1080/24705357.2018.1521709","url":null,"abstract":"Abstract The characteristics of a vortex power plant integrated in a weir have been investigated using computational fluid dynamics, with a special focus on all flow properties relevant to fish migration and energy conversion. The numerical model relies on a Reynolds-averaged, unsteady description using the volume-of-fluid method to describe the free surface. Several monitors are implemented, quantifying, in particular, the distribution of water velocities within the plant, and the probability of impact between drifting objects and turbine blades. Parameters, such as volume flow rate, turbine clearance, turbine speed and number of turbine blades have been varied. The systematic observation of the distribution of velocities and power density help assess the ecological impact of those modifications. It is found that a moderate increase of the turbine clearance and a reduction of the number of blades provide an attractive compromise between power output and opportunity for easy migration. Finally, it is predicted that the hazard associated with a fish hitting turbine blades can be greatly reduced by a careful adaptation of the turbine rotation velocity. Those developments are a first step towards a systematic numerical assessment of the fish-friendliness of machines operating under stringent ecological regulations.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"34 1","pages":"86 - 98"},"PeriodicalIF":0.0,"publicationDate":"2018-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89488469","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 : 2018-01-02DOI: 10.1080/24705357.2018.1457986
Christiana R. Czuba, J. Czuba, C. Magirl, A. Gendaszek, C. Konrad
ABSTRACT Human impacts on rivers threaten the natural function of riverine ecosystems. This paper assesses how channel confinement affects the scour depth and spatial extent of bed disturbance and discusses the implications of these results for salmon-redd disturbance in gravel-bedded rivers. Two-dimensional hydrodynamic models of relatively confined and unconfined reaches of the Cedar River in Washington State, USA, were constructed with surveyed bathymetry and available airborne lidar data then calibrated and verified with field observations of water-surface elevation and streamflow velocity. Simulations showed greater water depths and velocities in the confined reach and greater areas of low-velocity inundation in the unconfined reach at high flows. Data on previously published scour depth of bed disturbance during high flows were compared to simulated bed shear stress to construct a probabilistic logistic-regression model of bed disturbance, which was applied to spatial patterns of simulated bed shear stress to quantify the extent of likely bed disturbance to the burial depth of sockeye and Chinook salmon redds. The disturbance depth was not observed to differ between confined and unconfined reaches; however, results indicated the spatial extent of disturbance to a given depth in the confined reach was roughly twice as large as in the unconfined reach.
{"title":"Effect of river confinement on depth and spatial extent of bed disturbance affecting salmon redds","authors":"Christiana R. Czuba, J. Czuba, C. Magirl, A. Gendaszek, C. Konrad","doi":"10.1080/24705357.2018.1457986","DOIUrl":"https://doi.org/10.1080/24705357.2018.1457986","url":null,"abstract":"ABSTRACT Human impacts on rivers threaten the natural function of riverine ecosystems. This paper assesses how channel confinement affects the scour depth and spatial extent of bed disturbance and discusses the implications of these results for salmon-redd disturbance in gravel-bedded rivers. Two-dimensional hydrodynamic models of relatively confined and unconfined reaches of the Cedar River in Washington State, USA, were constructed with surveyed bathymetry and available airborne lidar data then calibrated and verified with field observations of water-surface elevation and streamflow velocity. Simulations showed greater water depths and velocities in the confined reach and greater areas of low-velocity inundation in the unconfined reach at high flows. Data on previously published scour depth of bed disturbance during high flows were compared to simulated bed shear stress to construct a probabilistic logistic-regression model of bed disturbance, which was applied to spatial patterns of simulated bed shear stress to quantify the extent of likely bed disturbance to the burial depth of sockeye and Chinook salmon redds. The disturbance depth was not observed to differ between confined and unconfined reaches; however, results indicated the spatial extent of disturbance to a given depth in the confined reach was roughly twice as large as in the unconfined reach.","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"45 1","pages":"17 - 4"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91324909","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 : 2018-01-02DOI: 10.1080/24705357.2018.1484331
C. Katopodis, P. Kemp
Morphodynamics and aquatic biota (i.e. plants and animals) interact through complex processes, to generate suitable, diverse and resilient habitats. We define morphodynamics in broad terms as the discipline of Earth surface characteristics and evolution which integrates hydrological, geomorphological and geological aspects. This definition is similar, although narrower to that offered by Paola et al. (2006), since we include ecological and biological aspects in Ecohydraulics. Complex physical processes are linked to planforms, longitudinal profiles and cross-sectional geometries in rivers, lakes and deltas and involve the cycling of water, sediment, ice, nutrients, solutes and organic materials in watersheds. Through surface, subsurface or groundwater flow, erosion, transport, deposition and ice conditions, morphodynamics shapes bars, pools, riffles, islands, side channels and other features in waterbodies (Paola et al. 2006; Wohl et al. 2015). Ecological dynamics, commonly understood less clearly, represent the even more complex life processes and food webs, responses by aquatic species and vegetation, populations and communities, as well as suitable habitats characterized by spatial complexity, connectivity and dynamism which meet biota life cycle requirements, enable ecosystem functionality and support biodiversity (Elosegi et al. 2010). Large differences in genetic flow, dispersal and mobility strategies or abilities of aquatic biota populations add another layer to this complexity and needs for more in-depth knowledge and understanding. With such complexities, it is not surprising that large knowledge gaps exist in morphodynamics and ecology, and particularly in the interaction between the two. Although often it is thought that geomorphology sets the template for biological processes (e.g. Vannote et al. 1980), recent studies indicate direct and indirect effects on physical processes from aquatic and riparian vegetation, particularly in the riparian zone (e.g. Gurnell et al. 2012), or even from fish through nutrient enrichment or potential effects on gravel substrates (e.g. DeVries 2012). Such interactions create numerous feedback mechanisms between biotic and abiotic processes, ecology and morphodynamics, generate further knowledge gaps and offer potentially great insights if elucidated though comprehensive studies. Since Ecohydraulics is at the interface between morphoand eco-dynamics and explores biota and physical interactions, breakthroughs in this interdisciplinary field become very challenging. At the same time, such challenges offer a plethora of opportunities for pioneering research and practical applications for interand trans-disciplinary advances in Ecohydraulics. River systems have influenced people and their settlements since the dawn of civilization, while humans continue to alter, regulate and manage them to: (1) suppress floods and control water levels; (2) supply water for domestic use, agriculture, recreation and many indu
形态动力学和水生生物群(即植物和动物)通过复杂的过程相互作用，产生合适的、多样化的和有弹性的栖息地。我们将形态动力学广义地定义为地球表面特征和演化的学科，它整合了水文、地貌和地质方面。这个定义与Paola等人(2006)提供的定义相似，但范围更窄，因为我们在生态水力学中包括了生态和生物方面。复杂的物理过程与河流、湖泊和三角洲的平台、纵向剖面和横截面几何形状有关，并涉及流域中水、沉积物、冰、营养物质、溶质和有机物质的循环。形态动力学通过地表、地下或地下水的流动、侵蚀、运输、沉积和结冰条件，塑造了水体中的沙洲、水池、河汊、岛屿、侧河道和其他特征(Paola et al. 2006;Wohl et al. 2015)。生态动力学，通常理解不太清楚，代表了更复杂的生命过程和食物网，水生物种和植被，种群和群落的响应，以及以空间复杂性，连通性和动态性为特征的适合栖息地，满足生物群生命周期要求，实现生态系统功能并支持生物多样性(Elosegi et al. 2010)。水生生物种群在遗传流动、扩散和迁移策略或能力方面的巨大差异，使这种复杂性又增加了一层，需要更深入的认识和理解。在如此复杂的情况下，形态动力学和生态学，特别是两者之间的相互作用方面存在巨大的知识差距也就不足为奇了。虽然通常认为地貌学为生物过程设定了模板(例如Vannote等人，1980)，但最近的研究表明，水生和河岸植被，特别是河岸地带的植被(例如Gurnell等人，2012)对物理过程产生了直接和间接的影响，甚至鱼类通过营养富集或对砾石基质的潜在影响(例如DeVries, 2012)。这种相互作用在生物和非生物过程、生态学和形态动力学之间创造了许多反馈机制，产生了进一步的知识空白，如果通过全面的研究加以阐明，可能会提供巨大的见解。由于生态水力学处于形态和生态动力学之间的界面，并探索生物群和物理相互作用，因此在这一跨学科领域取得突破变得非常具有挑战性。与此同时，这些挑战为生态水力学的跨学科进步提供了大量的开创性研究和实际应用机会。自文明出现以来，河流系统就影响着人类及其住区，而人类则继续改变、调节和管理它们，以实现以下目的:(1)抑制洪水和控制水位;(2)为生活、农业、娱乐和许多工业供水;(三)通航和水力发电;(4)流域间水从湿润区向干旱区转移;(五)治理泥沙、侵蚀和矿山废弃物;(6)将湿地和河流三角洲改造为农业或其他用途;(7)支持废物稀释、废物处理、伐木活动和造纸厂;(八)有意或者无意引入外来种的。河流的控制和管理改变了以生态动态性、栖息地连通性和物种多样性为特征的水生生态系统的动态性质。水坝、泵站、水渠、水电设施和其他基础设施以及生物入侵可能损害自然功能;使生物群的生存条件不适宜;碎片自由流动的河流;改变河流和溪流流量的时间和大小;破坏沉积物运输、养分循环、生物群运动以及与洪泛区和地下水的联系;影响长期河流形态、水质和冰况;增加对生物多样性的压力(Katopodis和Aadland, 2006年;Elosegi et al. 2010)。减少负面影响，了解生物群对变化的非生物环境的反应，制定和实施缓解措施，并评估其有效性，重点关注水生生物与形态动力学之间的动态相互作用，这需要创新的生态水力解决方案，并提出具有挑战性的研究问题。几千年来，人为影响留下了越来越普遍的形态特征。自然的河流、湖泊、三角洲甚至是河段，如果不是完全不存在的话，似乎也很罕见，尤其是考虑到航空运输和气候变化造成的污染。尽管人们普遍认识到，淡水对人类和水生生物、经济发展以及强大的生态系统功能至关重要。 全球范围内的这种河流改造已经并将继续改变生物多样性和生物群再分配，并对人类的水安全构成巨大风险。V - or - osmarty等人(2010)的一项全球分析发现，近80%的人类生活在对水安全的重大威胁中，而淡水水生栖息地退化速度的增加意味着数百种生物群正在受到威胁
{"title":"Challenges of integrating habitat for aquatic life and morphodynamics offer a plethora of opportunities for advances in Ecohydraulics","authors":"C. Katopodis, P. Kemp","doi":"10.1080/24705357.2018.1484331","DOIUrl":"https://doi.org/10.1080/24705357.2018.1484331","url":null,"abstract":"Morphodynamics and aquatic biota (i.e. plants and animals) interact through complex processes, to generate suitable, diverse and resilient habitats. We define morphodynamics in broad terms as the discipline of Earth surface characteristics and evolution which integrates hydrological, geomorphological and geological aspects. This definition is similar, although narrower to that offered by Paola et al. (2006), since we include ecological and biological aspects in Ecohydraulics. Complex physical processes are linked to planforms, longitudinal profiles and cross-sectional geometries in rivers, lakes and deltas and involve the cycling of water, sediment, ice, nutrients, solutes and organic materials in watersheds. Through surface, subsurface or groundwater flow, erosion, transport, deposition and ice conditions, morphodynamics shapes bars, pools, riffles, islands, side channels and other features in waterbodies (Paola et al. 2006; Wohl et al. 2015). Ecological dynamics, commonly understood less clearly, represent the even more complex life processes and food webs, responses by aquatic species and vegetation, populations and communities, as well as suitable habitats characterized by spatial complexity, connectivity and dynamism which meet biota life cycle requirements, enable ecosystem functionality and support biodiversity (Elosegi et al. 2010). Large differences in genetic flow, dispersal and mobility strategies or abilities of aquatic biota populations add another layer to this complexity and needs for more in-depth knowledge and understanding. With such complexities, it is not surprising that large knowledge gaps exist in morphodynamics and ecology, and particularly in the interaction between the two. Although often it is thought that geomorphology sets the template for biological processes (e.g. Vannote et al. 1980), recent studies indicate direct and indirect effects on physical processes from aquatic and riparian vegetation, particularly in the riparian zone (e.g. Gurnell et al. 2012), or even from fish through nutrient enrichment or potential effects on gravel substrates (e.g. DeVries 2012). Such interactions create numerous feedback mechanisms between biotic and abiotic processes, ecology and morphodynamics, generate further knowledge gaps and offer potentially great insights if elucidated though comprehensive studies. Since Ecohydraulics is at the interface between morphoand eco-dynamics and explores biota and physical interactions, breakthroughs in this interdisciplinary field become very challenging. At the same time, such challenges offer a plethora of opportunities for pioneering research and practical applications for interand trans-disciplinary advances in Ecohydraulics. River systems have influenced people and their settlements since the dawn of civilization, while humans continue to alter, regulate and manage them to: (1) suppress floods and control water levels; (2) supply water for domestic use, agriculture, recreation and many indu","PeriodicalId":93201,"journal":{"name":"Journal of ecohydraulics","volume":"41 1","pages":"1 - 3"},"PeriodicalIF":0.0,"publicationDate":"2018-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77930121","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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