Integrating two-dimensional water temperature simulations into a fish habitat model to improve hydro- and thermopeaking impact assessment

Storage hydropower plants, which are an important component of energy production in Switzerland, can lead to hydro- and thermopeaking, affecting river habitats and organisms. In this study, we developed an approach for integrating water temperature simulations into a habitat model to assess the impact of both hydro- and thermopeaking on the availability of suitable fish habitats. We focused on the habitat requirements of juvenile brown trout (Salmo trutta) in a semi-natural braided floodplain along the Moesa River (Southern Switzerland) in early summer. First, we defined different scenarios (with and without hydropeaking) based on the local hydrological and meteorological conditions. Second, we used a two-dimensional depth-averaged hydro- and thermodynamic model to simulate the spatial distributions of water depth, flow velocity, and water temperature. Third, we applied generalized preference curves for juvenile brown trout to identify hydraulically suitable habitats, and developed a new index to assess the availability of thermally suitable habitats. Finally, we quantified the extent to which hydraulically and thermally suitable habitats overlap in space and time. During both base and peak flow phases, most of the hydraulically and thermally suitable habitats are located in the side channels. High flow conditions combined with strong cold-thermopeaking lead to a higher thermal heterogeneity. However, disconnected habitats originate in the dewatering zone, increasing the risk of stranding as well as thermal stress. By helping to better understand the effects of thermopeaking on the availability of fish habitats, our approach could contribute to the design and evaluation of ecological restoration in hydropeaking rivers.     

Downstream environmental effects of dam operations: Changes in habitat quality for native fish species

Hydropeaking dam operation and water extractions for irrigation have been broadly stated as alterations to natural flow regimes, which have also been noticed in the Biobío Watershed, in Central Chile, since 1996. In the Biobío River, most of native fish species are endemic and very little is known about them. Their ecological and social values have never been estimated, and there is lack of information about their habitat preferences. Furthermore, changes on fish habitat availability due to natural and/or man‐made causes have not been evaluated. In this study, eight native fish species, in a representative reach of the Biobío River, were studied and their preferred habitats were surveyed and characterized. A hydrodynamic model was built and linked to the fish habitat simulation model CASiMiR. Fuzzy rules and fuzzy sets were developed for describing habitat preference of the native fish species. CASiMiR was then used to simulate how physical habitat conditions vary due to flow control (i.e. upstream dams). Results show how overall habitat quality, expressed as weighted usable area (WUA) and hydraulic habitat suitability (HHS), changes and fluctuates due to the dam operation and how the daily hydropeaking is influencing quantity, quality and location of different habitats. The study suggests that the analysed fish are highly susceptible to flow control, as dams are currently operated, and fish habitat improvement suggestions are proposed. Copyright © 2010 John Wiley & Sons, Ltd.     

A Fuzzy Rule‐based Model for the Assessment of Macrobenthic Habitats under Hydropeaking Impact

Hydropeaking presents one of the large impacts on river ecology and is gaining importance because of an increasinlgy volatile energy market with high portions of new renewable energies dependent on local climate conditions. This study presents the application of a fuzzy logic model for the investigation of macrobenthic habitats under hydropeaking conditions in the Norwegian river Surna. Preference data of the three taxa Baetis rhodani, Hydroptila spp. and Allogamus auricollis with distinctively different habitat requirements related to near‐bottom flow forces (high/low forces, and narrow range) are used. These data are transferred into the multivariate fuzzy rule‐based physical habitat model Computer Aided Simulation of Instream flow and Riparia in order to integrate water depth and river bed substrate as additional parameters. Permanently available habitats (persistent habitats) are assessed for different scenarios of hydropeaking operation. It is found that the amount of persistently high‐quality habitat is closely related to the size and range of fluctuations in hydraulic conditions occuring during hydropeaking events. Effects are much more distinct for species with a narrow range of hydraulic preference. The integration of water depth in the simulations has a noticable impact on the amount and quality of predicted habitats. Substrate conditions in the investigation site are homogeneous and, in the specific case considered, do not have a significant impact. The study suggests persistent habitats as a suitable indicator of hydropeaking impact on organisms with low mobility. The persistent habitat approach takes into account that organisms with a low mobility and a distinct range of tolerance related to hydraulic stress tend to settle in areas with permanently stable conditions. Multivariate aspects are accounted through the fuzzy rule‐based approach and do clearly affect habitat predictions. Habitat requirements of species particularly sensitive to hydropeaking are proposed for the investigation and application in the future. Copyright © 2016 John Wiley & Sons, Ltd.     

A probability-based model to quantify the impact of hydropeaking on habitat suitability in rivers

A negative effect of hydropower on river environment includes rapid changes in flow and habitat conditions. Any sudden flow change could force fish to move towards a refuge area in a short period of time, causing serious disturbances in the life cycle of the fish. A probability-based model was developed to quantify the impact of hydropeaking on habitat suitability for two fish species, brown trout (Salamo trutta) and Grayling (Thymallus thymallus). The model used habitat preference curves, river velocity and depth to develop the suitability maps. The suitability maps reveal that habitat suitability deteriorates as flow increases in the studied part of the river. The probability model showed that, on average, suitability indices are higher for adult grayling than juvenile trout in hydropeaking events in this part of the river. The method developed shows the potential to be used in river management and the evaluation of hydropeaking impacts in river systems affected by hydropower.     

Ground beetle habitat templets and riverbank integrity

The habitat templet approach was used in a scale‐sensitive bioindicator assessment for the ecological integrity of riverbanks and for specific responses to river management. Ground beetle habitat templets were derived from a catchment‐scale sampling, integrating the overall variety of bank types. This coarse‐filter analysis was integrated in the reach‐scale fine‐filtering approaches of community responses to habitat integrity and river management impacts. Higher species diversity was associated with the higher heterogeneity in bank habitats of the un‐navigable river reaches. The abundant presence of habitat specialists in the riverbank zone allows a habitat integrity assessment based on the habitat templet indicator species. Significant responses were detected for channel morphology in the width‐to‐depth ratio and for hydrological regime in peak frequency and peak velocity, enabling the development of evaluation methods for the impact assessment of river management and flood protection strategies. Copyright © 2005 John Wiley & Sons, Ltd.     

Flow amplitude or up-ramping rate? Quantifying single and combined effects on macroinvertebrate drift during hydropeaking simulations,considering sensitive traits

The hydrological regime of many alpine rivers is heavily altered due hydroelectric power generation. Hydropeaking operation produces frequent and irregular discharge fluctuations. Depending on the operational changes of flow amplitude and/or up-ramping rate as well as on river morphology, hydropeaking can lead to quick and strong variations in hydraulic stress affecting stream invertebrates and causing increased drift. In the present flume experimental study, we analyzed trait-specific drift reactions to single and combined effects of increased flow amplitude and up-ramping rate. We analyzed taxa according to their hydraulic habitat preference and flow exposure, as these traits seem to be indicative toward hydropeaking. The results show that the sudden increase in discharge and related flow velocity led to increased macroinvertebrate drift proportions in hydropeaking treatments, which differed significantly to parallel control runs (mean drift proportion in all hydropeaking setups: 13% compared to 5% in controls). Increasing flow amplitudes led to an increase in drift for most taxa and traits. This was particularly significant for taxa associated with lentic areas. The effect of the up-ramping rate on macroinvertebrate drift was nonsignificant but showed strong interactive effects with the flow amplitude, especially for taxa dwelling on the substrate surface. Our results therefore indicate that discharge-related parameters, such as flow velocity, primarily affect macroinvertebrate drift and the importance of the up-ramping rate increases, if certain discharge-related thresholds are exceeded. Vice versa, a reduction of the up-ramping rate at hydropeaking events with high flow amplitudes may reduce the effect on macroinvertebrate drift. Flow-exposed (surface) and flow-sensitive (lentic) taxa showed distinct drift reactions following hydropeaking treatments, which were significantly higher compared to effects on taxa associated to lotic and interstital habitats. Therefore, we conclude that both traits (hydraulic and vertical habitat preference) have proven as promising for analyzing hydropeaking effects. The trait classifications should be extended to a higher number of taxa and to different life stages as these may show different drift patterns.     

Response of Fish Communities to Hydrological and Morphological Alterations in Hydropeaking Rivers of Austria

Climate change asks for the reduction in the consumption of fossil‐based fuels and an increased share of non‐regulated renewable energy sources, such as solar and wind power. In order to back up a larger share of these intermittent sources, ‘battery services’ are needed, currently provided only in large scale by hydropower, leading to more rapid and frequent changes in flows (hydropeaking) in the downstream rivers. Increased knowledge about the ecosystem response to such operations and design of cost‐effective measures is needed. We analysed the response of fish communities to hydropeaking (frequency, magnitude, ramping rate and timing) and the interaction with the habitat conditions in Austrian rivers. An index of biotic integrity (Fish Index Austria) was used to compare river sections with varying degrees of flow fluctuations under near‐natural and channelized habitat conditions. The results showed that habitat conditions, peak frequency (number of peaks per year), ramping rate (water level variation) and interaction between habitat and ramping rate explained most of the variation of the Fish Index Austria. In addition, peaking during the night seems to harm fish more than peaking during the day. Fish communities in hyporhithral and epipotamal types of rivers are more affected by hydropeaking than those in metarhithral type of rivers. The results support the findings of other studies that fish stranding caused by ramping rates >15 cm h^?1 are likely to be the main cause of fish community degradation when occurring more often than 20 times a year. While the ecological status degrades with increasing ramping rate in nature‐like rivers, fish communities are heavily degraded in channelized rivers regardless of the ramping rate. The mitigation of hydropeaking, therefore, requires an integrative approach considering the combined effects of hydrological and morphological alterations on fish. © 2014 The Authors. River Research and Applications published by John Wiley & Sons, Ltd.     

Influence of habitat heterogeneity and bed surface complexity on benthic invertebrate diversity in a gravel‐bed river

Maintaining or restoring physical habitat diversity is a central tenet of sustainable river management, yet a link between habitat and ecological diversity in fluvial systems has long remained equivocal. The lack of consistent evidence partly reflects the problems of characterizing habitat in ways that are ecologically meaningful. This paper assesses the influence of habitat heterogeneity and complexity on macroinvertebrate assemblages in a mountain gravel‐bed river. With the use of 0.1‐m resolution data obtained from an acoustic Doppler current profiler, heterogeneity and complexity in hydraulic conditions and bed topography were characterized using 13 metrics applied to 30 areas, each 1 m², with an invertebrate sample collected from each area. Turnover of invertebrate taxa (i.e., β‐diversity) between sampled areas was rather limited, but observed differences in diversity were related significantly to several metrics of habitat heterogeneity. Invertebrate abundance was related to habitat diversity, patch size coefficient of variation, and patch size, whereas the Shannon diversity was related to the number of patches and patch size. None of the habitat complexity metrics accounted for a significant amount of observed variation in invertebrate communities between sampled areas. The paper demonstrates that high‐resolution data can help reveal relationships between habitat and benthic invertebrate diversity.     

河流栖息地适合度曲线与分级评价标准研究

河流栖息地具有多尺度、多等级、斑块化分布和动态变化等重要特征,常通过揭示栖息地质量的关键环境因子适合度来开展河流栖息地质量评价。本文基于国内外多种溪流型鱼类栖息地环境的流速、水深范围与偏好的流速、水深、水温研究成果,结合中国浙江省瓯江干流河段的自然环境特征和多样性的水生物学特点,选取喜缓流水型鱼类-唇䱻作为指示性物种,研究了河流栖息地关键环境因子:水深、流速、水温与水质适合度曲线,采用优、良、中、差分级评价方法,以流速、水深、水温和水质类别作为主要的判据因子,确定了河流栖息地评估的分级标准,为河流栖息地质量评价和生态适应性管理提供了科学依据。     

Technologies for the study of hydropeaking impacts on fish populations: Applications,advantages, outcomes,and future developments

Dam construction and streamflow regulation are increasing throughout the world, with impacts in impounded aquatic ecosystems. Hydropower dams, some of them causing a phenomenon called “hydropeaking” during their operation, are known for having a variety of impacts on downstream aquatic biota, particularly fish, and respective habitat. This can result in significant changes, from the community (e.g., fish assemblage structure) to the individual level (e.g., physiological and behavioural adjustments). Researchers and managers involved in the assessment of hydropeaking impacts must be resourceful and use methods that allow their precise evaluation, from large to fine-scale habitat and biological responses. In the last decades, technological advances allowed for the development of techniques and instrumentations that are increasingly being used in hydropeaking impact and mitigation assessments. This paper aims to provide a review, to researchers and managers interested in this field, of some of the most innovative methods and techniques, involving technology, that are available to study hydropeaking effects on downstream ecosystem, particularly from a fish perspective. We discuss the fundamentals behind such techniques, their advantages, and disadvantages, while also providing practical examples of their application and of the type of results that can be obtained. We finish by discussing some of the shortcomings of these methods and how related technology can evolve to solve current limitations.     

A comparison of avian communities and habitat characteristics in floodplain forests associated with valley plugs and unchannelized streams

Channelization of streams associated with floodplain forested wetlands has occurred extensively throughout the world and specifically in the southeastern United States. Channelization of fluvial systems alters the hydrologic and sedimentation processes that sustain these systems. In western Tennessee, channelization and past land‐use practices have caused drastic geomorphic and hydrologic changes, resulting in altered habitat conditions that may affect avian communities. The objective of this study was to determine if there were differences in avian communities utilizing floodplain forests along unchannelized streams compared to channelized streams with valley plugs, areas where sediment has completely filled the channel. During point count surveys, 58 bird species were observed at unchannelized sites and 60 species were observed at valley plug sites. Species associated with baldcypress‐tupelo (Taxodium‐Nyssa) swamps (e.g. Great Egret (Ardea albus) and Black‐crowned Night Heron (Nycticorax nycticorax)) and mature hardwood forests with open midstories (e.g. Eastern Wood‐Pewee (Contopus virens), Yellow‐throated Vireo (Vireo flavifrons), Cerulean Warbler (Dendroica cerulea) and Scarlet Tanager (Piranga olivacea)) were either only found at unchannelized sites or were more abundant at unchannelized sites. Conversely, species associated with open and early successional habitats (e.g. Tree Swallow (Tachycineta bicolor), Northern Mockingbird (Mimus polyglottos) and Blue Grosbeak (Passerina caerulea)) were either only found at valley plug sites or were more abundant at valley plug sites. Results of habitat modelling suggest that the habitat characteristics of floodplain forests at unchannelized sites are more suitable for Neotropical migrant bird species of conservation concern in the region than at valley plug sites. This study, in combination with previous research, demonstrates the ecological impacts of valley plugs span across abiotic and biotic processes and tropic levels. Copyright © 2010 John Wiley & Sons, Ltd.     

MORPHOLOGICALLY RELATED INTEGRATIVE MANAGEMENT CONCEPT FOR RECONNECTING ABANDONED CHANNELS BASED ON AIRBORNE LiDAR DATA AND HABITAT MODELLING

Most of the large rivers are heavily degraded and lack near‐natural conditions due to high human pressure (agricultural use and settlements) especially on former inundation areas. Hence, it is rarely possible to ‘restore’ predisturbance conditions of rivers and their floodplains. Further, river or floodplain restoration programs are often based on type‐specific reference conditions. Those reference conditions are mainly determined on the basis of historical maps not giving any information of, for example, sediment supply, flood frequency and vegetation cover (density). Especially for improving the ecological status of rivers with abandoned channel features, key habitats for target fish species have to be restored by reconnecting floodplains and their secondary channel system. In addition, because of the necessity of improving the ecological status, there is growing interest in interdisciplinary river restoration techniques. Within the presented article, an integrative concept is derived based on Light Detection and Ranging measurements and numerical modelling with respect to river dynamics (hydrologic and morphological). Further habitat modelling, based on unsteady depth‐averaged two‐dimensional hydrodynamics, is applied with a focus on the mesounit scale. For testing the conceptual model, various river reaches at the Morava River were selected, featuring different morphological characteristics. It was found that the applied management concept allows considering the important issues of river dynamics (morphological/hydrologic) using a flow‐ and flood‐pulse approach for identifying bottlenecks of target species at the Morava River. The reconnection of abandoned channels will result in an increase of hydromorphological heterogeneity and/or woody debris within the study reach. This might be of high relevance for habitat features (e.g. backwater habitats) especially for flow pulses between low flow and mean flow and/or in reaches without abandoned channels between low‐flow and the bankfull stage. Copyright © 2012 John Wiley & Sons, Ltd.     

Two-dimensional physical habitat modeling of effects of habitat structures on urban stream restoration

River corridors, even if highly modified or degraded, still provide important habitats for numerous biological species, and carry high aesthetic and economic values. One of the keys to urban stream restoration is recovery and maintenance of ecological flows sufficient to sustain aquatic ecosystems. In this study, the Hongje Stream in the Seoul metropolitan area of Korea was selected for evaluating a physically-based habitat with and without habitat structures. The potential value of the aquatic habitat was ...     

Soundpeaking – Hydropeaking induced changes in river soundscapes

Underwater soundscapes and their unique acoustic signatures are mainly generated through movement of streambed sediment, subsequent particle collisions, and turbulence created by water flowing over submerged obstructions such as rocks and woody debris. This study characterized river soundscapes in Alpine rivers of Trentino, (North East Italy) with the combined use of hydrophones and a new microelectricalmechanical systems based device (Hydroflown) that is capable of measuring particle velocity components of the sound field. Pool and riffle habitats affected and unaffected by hydropeaking were characterized in terms of their particle velocity and sound pressure levels across 10 octave bands (acoustic signature) to assess temporal variations in overall sound levels, changes in frequency composition, and relationship to hydromorphological habitat parameters. Data revealed that soundscapes affected by hydropeaking are highly homogenized, and sound pressure levels are strongly correlated with turbine discharge, which results in rapid, multiple‐fold spikes in low frequency amplitude levels within the typical hearing range of common teleost fish species. The outcomes of this study provide the basis for further examination of the resulting behavioural and physiological responses of organisms to anthropogenic changes in river soundscapes.     

Response of fish assemblages to restoration of rapids habitat in a Great Lakes connecting channel

Rapids habitats are critical spawning and nursery grounds for multiple Laurentian Great Lakes fishes of ecological importance such as lake sturgeon, walleye, and salmonids. However, river modifications have destroyed important rapids habitat in connecting channels by modifying flow profiles and removing large quantities of cobble and gravel that are preferred spawning substrates of several fish species. The conversion of rapids habitat to slow moving waters has altered fish assemblages and decreased the spawning success of lithophilic species. The St. Marys River is a Great Lakes connecting channel in which the majority of rapids habitat has been lost. However, rapids habitat was restored at the Little Rapids in 2016 to recover important spawning habitat in this river. During the restoration, flow and substrate were recovered to rapids habitat. We sampled the fish community (pre- and post-restoration), focusing on age-0 fishes in order to characterize the response of the fish assemblage to the restoration, particularly for species of importance (e.g. lake whitefish, walleye, Atlantic salmon). Following restoration, we observed a 40% increase in age-0 fish catch per unit effort, increased presence of rare species, and a shift in assemblage structure of age-0 fishes (higher relative abundance of Salmonidae, Cottidae, and Gasterosteidae). We also observed a “transition” period in 2017, in which the assemblage was markedly different from the pre- and post-restoration assemblages and was dominated by Catostomidae. Responses from target species were mixed, with increased Atlantic salmon abundance, first documented presence of walleye and no presence of lake sturgeon or Coregoninae.     

Spatial distribution and geomorphic condition of fish habitat in streams: an analysis using hydraulic modelling and geostatistics

Reach‐scale physical habitat assessment scores are increasingly used to make decisions about management. We characterized the spatial distribution of hydraulic habitat characteristics at the reach and sub‐reach scales for four fish species using detailed two‐dimensional hydraulic models and spatial analysis techniques (semi‐variogram analyses). We next explored whether these hydraulic characteristics were correlated with commonly used reach‐scale geomorphic assessment (RGA) scores, rapid habitat assessment (RHA) scores, or indices of fish biodiversity and abundance. River2D was used to calculate weighted usable areas (WUAs) at median flows, Q₅₀, for six Vermont streams using modelled velocity, depth estimates, channel bed data and habitat suitability curves for blacknose dace (Rhinichthys atratulus), brown trout (Salmo trutta), common shiner (Notropis cornutus) and white sucker (Catostomus commersoni) at both the adult and spawn stages. All stream reaches exhibited different spatial distributions of WUA ranging from uniform distribution of patches of high WUA to irregular distribution of more isolated patches. Streams with discontinuous, distinct patches of high score WUA had lower fish biotic integrity measured with the State of Vermont's Mixed Water Index of Biotic Integrity (MWIBI) than streams with a more uniform distribution of high WUA. In fact, the distribution of usable habitats may be a determining factor for fish communities. A relationship between predicted WUAs averaged at the reach scale and RGA or RHA scores was not found. Future research is needed to identify the appropriate spatial scales to capture the connections between usable patches of stream channel habitat. Copyright © 2008 John Wiley & Sons, Ltd.     

Seasonal selection of habitat by Spotted Bass and Shorthead Redhorse in a regulated river in the Midwest,USA

Riverine fish populations depend on habitats supporting their resource and life history needs. Dynamic streamflow caused by river regulation or natural events influences the distribution of downstream habitat characteristics. Through studying habitat selection, we can identify the most utilized and valuable habitats for the success of native fishes. We determined seasonal habitat selection of two common, native fish species on the Osage River downstream of Bagnell Dam, a hydroelectric dam in central Missouri, from April 2016 to June 2017 using radio telemetry. Spotted Bass (Micropterus punctulatus) are nest‐guarders, sight feeders, and habitat generalists, whereas Shorthead Redhorse (Moxostoma macrolepidotum) are fluvial dependent, migratory, and benthic feeders. Bayesian discrete choice analyses determined that both species selected particular water depth, velocity, and presence of submerged cover in some or all seasons, even as available habitat changed. Spotted Bass selected water depths <4.0 m near submerged cover during all seasons, low velocity during spring and summer, and near‐bank habitat in all seasons except spring. Shorthead Redhorse used fast flowing habitat during spring, 0.4–1.1 m/s velocity during summer, and low velocity in fall and winter (0.1–0.5 m/s). Shorthead Redhorse used submerged cover in all seasons except summer and selected specific ranges of depth within spring (2.4–4.4 m), summer (3.3–6.7 m), and winter (1.1–2.3 m). Our findings suggest that maintaining habitats with cover and diverse water depths and velocities, particularly both low and high velocity habitats during spring, may promote resilience by providing beneficial habitats for native fishes.     

ESTIMATION OF JUVENILE SALMON HABITAT IN PACIFIC RIM RIVERS USING MULTISCALAR REMOTE SENSING AND GEOSPATIAL ANALYSIS

We conducted a regional classification and analysis of riverine floodplain physical features that represent key attributes of salmon rearing habitats. Riverine habitat classifications, including floodplain area and river channel complexity, were derived at moderate (30 m) spatial resolution using multispectral Landsat imagery and global terrain data (90 m) encompassing over 3 400 000 km² and most North Pacific Rim (NPR) salmon rivers. Similar classifications were derived using finer scale (i.e. ≤ 2.4‐m resolution) remote sensing data over a smaller set of 31 regionally representative flood plains. A suite of physical habitat metrics (e.g. channel sinuosity, nodes, floodplain width) were derived from each dataset and used to assess the congruence between similar habitat features at the different spatial scales and to evaluate the utility of moderate scale geospatial data for determining abundance of selected juvenile salmon habitats relative to fine scale remote sensing measurements. The resulting habitat metrics corresponded favorably (p < 0.0001) between the moderate scale and the fine scale floodplain classifications; a subset of these metrics (channel nodes and maximum floodplain width) also were strong indicators (R² > 0.5, p < 0.0001) of floodplain habitats defined from the finer scale analysis. These relationships were used to estimate the abundance and distribution of three critical shallow water floodplain habitats for juvenile salmon (parafluvial and orthofluvial springs, and shallow shore) across the entire NPR domain. The resulting database provides a potential tool to evaluate and prioritize salmon conservation efforts both within individual river systems and across major catchments on the basis of physical habitat distribution and abundance. Copyright © 2011 John Wiley & Sons, Ltd.     

水库建设影响河流鱼类生境的保护研究

由于水库的建设会对河流产生阻隔,从而影响鱼类洄游、产卵、索饵等,本文以赤峰市东台子水库为例,结合西拉木伦河流域特征、水库特性及鱼类生活习性、繁殖特征等,简要阐述了通过采取水库生态调度、鱼类增殖放流站及鱼道建设等保护措施,对河道内的鱼类生境进行有效保护,可减少水库工程建设对鱼类生境的影响。     

大坝对鱼类栖息地的影响及评价方法述评

本文总结了大坝建设造成水流状态、水温、水质、底质和地形等因素的变化对鱼类栖息地造成的影响，并归纳了目前国内外对栖息地预测评价的主要方法，对每一种评价方法的特点进行了分析，最后对可采取的生态补偿措施进行了介绍。本文得到的结论为，大坝建设对鱼类的影响很大，但可以通过补偿措施加以恢复。