共查询到20条相似文献，搜索用时 15 毫秒
1.
Marcel Medinas de Campos Hans M. Tritico Pierre Girard Peter Zeilhofer Stephen K. Hamilton Ibraim Fantin‐Cruz 《河流研究与利用》2020,36(3):452-464
There are 104 hydroelectric facilities proposed to be installed in the watersheds that feed the Pantanal, a vast floodplain wetland located mostly in Brazil. The Pantanal is host to 23 long‐distance migratory fish species that ascend upland tributaries to spawn. A Geographic Information System was used to predict the impact of hydroelectric dams on potential migration routes for these species. Both anthropogenic (hydroelectric dams) and natural barriers were included in the analysis. Natural barriers were identified by river slope. Critical river slopes of 10 and 25%, above which fish were predicted to be incapable of ascending, were modeled as natural barriers. Based on this model, we show that between 2 and 14% of rivers in the Pantanal watershed are naturally blocked to fish migration. An additional 5 to 9% of rivers are currently blocked due to 35 existing hydroelectric facilities. If all proposed dams are built, the area flooded by new reservoirs will triple and the river kilometers blocked will double, blocking 25 to 32% of the river system to fish migration. The Taquari and Cuiabá River sub‐basins will be the most impacted, each having more than 70% of their rivers blocked. The impact of individual proposed facilities on the loss of migration routes is related to their proximity to existing barriers. Fourteen of the proposed dams are upstream from existing barriers and will therefore not further restrict long‐distance fish migration routes while proposed dams are predicted to close an additional 11,000 to 12,000 km of river channels. 相似文献
2.
M. J. Feio W. R. Ferreira D. R. Macedo A. P. Eller C. B. M. Alves J. S. França M. Callisto 《河流研究与利用》2015,31(1):70-84
Here, we set target values to measure the ecological improvement of streams, based on invertebrate communities, riparian vegetation, instream habitat conditions and water chemistry. The study area is a large tropical catchment (Rio das Velhas, Minas Gerais, Brazil) affected by pastures, mining areas and a large urbanized area but also includes natural protected areas. Two stream types were found in the catchment, based on stream size, elevation, climate and geology with significantly different macroinvertebrate communities. In spite of a marked wet/dry seasons' climatic pattern, that does not result in the segregation of communities. Four classes of global degradation (IV—bad to I—good condition) were defined based on the available abiotic information, corresponding to a gradient in structure and biotic metrics of macroinvertebrate communities, matching the current knowledge on taxa sensitivity to pollution and general disturbance. Class I corresponds to target conditions to be achieved under restoration programmes. Using this approach, we were able to detect an improvement of abiotic conditions in four urban streams that benefited from enhancement measures in 2007–2008. However, invertebrate communities improved clearly in only one site (biotic metrics and community structure). Our study highlighted that good water quality alone is not enough and that only the combined effect of water quality, riparian vegetation and instream habitat condition enhancement resulted in the improvement of invertebrate communities. An important limiting factor for macroinvertebrate communities' recovery may be the distance to source populations. We concluded that the combined use of biological and abiotic target values for measuring the recovery of streams is needed to fully achieve an ecological restoration. This approach can also be valuable in the regular monitoring of streams to assess stream degradation. Target values based on other biological elements, such as fishes and algae, and functional processes could also contribute to define more global and realistic goals. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
3.
This study was undertaken as part of a long‐term investigation of the ability of high‐level fishways to rehabilitate fish communities upstream of high dams. Effects of Tallowa Dam on fish of the Shoalhaven River system were studied by comparing species abundances, population size‐structures and the structure of fish communities above and below the dam. Fish were sampled twice yearly for two years at 12 sites throughout the catchment. Species richness was greater downstream of the dam, with 21 species, compared to 16 species upstream of the dam. Ten diadromous species are believed to be extinct above the dam because of obstructed fish passage. Another four migratory species capable of climbing the wall have reduced abundances upstream. Accumulations of fish, particularly juveniles, directly below the dam were evident for nine species. Fish communities upstream and downstream of the dam differed significantly, identifying the dam as a significant discontinuity in the available fish habitats within the system. Historical evidence suggests that before the dam was built, fish communities from the tidal limit to at least 130 m elevation were largely continuous. This study has demonstrated that Tallowa Dam is a major barrier to fish migration and has had adverse effects on the biodiversity of the system. The creation of Lake Yarrunga by Tallowa Dam has resulted in distinctive fish communities in riverine and lacustrine habitats. Populations of five species that occur both upstream and downstream of the dam have developed differences in their size structures. The fish community downstream of the dam also differs from its historical condition because of the virtual disappearance of Australian grayling (Prototroctes maraena) and the establishment of non‐native species. A high‐level fishway is now being designed for the dam to restore fish passage. Data from this study will serve as a baseline against which to assess the effectiveness of the fishway in rehabilitating fish communities of the river system. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
4.
张学进 《中国水能及电气化》2015,(7)
本文分析了绿色小水电建设工作背景,结合中央和地方已有的绿色小水电工作基础,提出了绿色小水电建设的基本思路、建设要求以及当前和“十三五”期间加快推进绿色小水电建设的工作打算。 相似文献
5.
6.
中小河流水电梯级开发对鱼类资源影响显著,主要表现为鱼类栖息环境的破坏。通过对广东省东江一级支流秋香江进行水生态调查与采样分析,对秋香江的鱼类资源现状进行了评估,并与历史资料进行对比研究,结果表明:由于秋香江流域水电梯级开发和其他人类活动导致鱼类缺乏合适的栖息环境,鱼类的种类和数量与历史记录相比急剧减少;鱼类种群结构较不稳定;鱼类多样性也逐渐降低。中小河流水电梯级开发应注重对整个流域进行统筹规划,保护河流水生态系统的完整性,严格要求水电站建设泄流设施并对其运行情况加强监管。 相似文献
7.
Adverse effects of 23 bypass- or mill stream-type small hydropower stations (SHPSs) have been studied by traditional benthological and ichthyological techniques. Four locations, if available, were distinguished for each SHPS: the natural flow sections (NFS) above and below the SHPS area, the mill stream or diversion channel bringing water to the turbine, and the reduced discharge section (RDS) of the former stream course. Most SHPSs took a high percentage of the stream discharge (turbine intake capacity was usually bigger than average yearly discharge of the stream at a given point). Despite this, the decrease in the stream-wetted area was relatively low (usually 0–30%). The changes of benthic communities did not show any distinct trend explicable by the SHPS operation. Mechanical damage of fish by turbines was found rather rarely with SHPSs. The diverting weir (which usually distributes the discharge between the RDS and the mill stream), in combination with the abstraction of water for SHPSs, was an important migration barrier for resident fish in 30% of SHPSs. Water abstraction causes succession from large-bodied fish species (adult brown trout, chub, dace, grayling, etc.) towards small-bodied fish (trout fry, minnow, bullhead, stone loach, gudgeon). Average individual weight and fish biomass decreased four times in RDSs. Fish biomass losses exhibit significant negative relationships to the ratio of turbine intake capacity and stream discharge. Several mitigation measures are suggested. © 1997 John Wiley & Sons, Ltd. 相似文献
8.
Many studies have investigated the ecological changes that occur below dams that release cold, hypolimnetic water, but very few studies have looked at the effects of the release of warm, surface waters. The effect of small, surface release dams on downstream thermal regimes is a major habitat concern for many cold‐water systems, however. The objective of this study was to examine the effects of summer temperature increases due to impoundment on downstream fish and macroinvertebrate communities in cold‐water streams. We sampled fish, macroinvertebrates and habitat upstream and downstream of dams on ten rivers during the summers of 1998 and 1999. Changes in mean summer temperature downstream varied from a cooling of 1 °C to an increase of more than 5 °C. Increasing temperatures downstream coincided with lower densities of several cold‐water fish species, specifically brown trout (Salmo trutta), brook trout (Salvelinus fontinalis) and slimy sculpin (Cottus cognatus) while overall fish species richness increased downstream. Density of mottled sculpin (Cottus bairdi), another cold‐water species, was not related to temperature changes below the dams. Macroinvertebrates showed shifts in community composition below dams that increased temperature. This study provides information useful for determining the extent of impact of these small, surface release dams, which are abundant across the country. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
9.
Small hydropower projects (SHPs) are promoted as low-impact alternatives for large hydropower. SHPs are generally commissioned on small- to medium-sized mountainous rivers, often in biodiverse regions, with backing in the form of subsidies, facultative policies and exemption from impact assessments as they are considered ‘green’. However, the ecological impacts of SHPs are understudied especially in highly seasonal tropical streams of Western Ghats of India, a global biodiversity hotspot and a distinct freshwater fish eco-region. We compared SHP-affected segments of a dammed and an undammed river in the Western Ghats of Karnataka, to assess how altered flow regime affects seasonal variability in habitat and water quality, and influences fish assemblage structure. We found that flow alteration by the SHP varied between different segments of the dammed river and with season. Furthermore, the nature of flow alteration influenced habitat variability, water quality and fish assemblage response in the dammed river. We observed that the dewatered segment of the dammed river experienced a lotic to lentic shift in habitat and water quality, which favoured fish species with eurytopic affinities. Fluctuating flows in the downstream segment subdued natural variability in flow regime and created novel habitats and water-quality conditions, affecting fish assemblages. The upstream segment of the dammed river retained natural variability in habitat and water quality, but did not mimic the undammed river in terms of fish composition. We also observed potential constraints on recruitment for migratory species of fish in the dammed river. Based on our results, we suggest how the placement of dewatered segment, and timing the closure of SHP operation in dry season based on ecological thresholds are potential solutions to mitigate the impacts of the SHPs. Furthermore, we recommend effective impact assessments, and adaptive management with active interventions to maintain genetic and ecological connectivity, as key to enhance the sustainability of the SHPs. 相似文献
10.
目前有些地方小水电的管理局面比较混乱，不利于小水电的长远发展。通过对永丰县小水电开发和管理现状的分析，建议设立小水电协会，强化小水电行业管理。 相似文献
11.
论大坝与生态 总被引：29，自引：1，他引：28
“大坝与生态”是人与自然和谐相处中的一个重要课题。从普遍意义上讲,修建大坝可能带来的生态问题主要有移民、对泥沙和河道的影响、对大气的影响、水体变化带来的影响、对鱼类和生物物种的影响、对文物和景观的影响、地质灾害、溃坝等八个方面。在不同的流域、不同的河段、不同的坝址上建坝,带来的生态问题是不同的,一定要具体问题具体分析。水利水电工作者必须高度重视水利水电发展中的生态问题,正确认识开发与生态的关系,科学评价大坝可能导致的生态环境问题,用科学发展观和人与自然和谐相处的理念正确认识并妥善处理现阶段遇到的问题,确保我国水利水电建设事业快速健康地发展。 相似文献
12.
The Penobscot River drains the largest watershed in Maine and once provided spawning and rearing habitats to 11 species of diadromous fishes. The construction of dams blocked migrations of these fishes and likely changed the structure and function of fish assemblages throughout the river. The proposed removal of two main‐stem dams, improved upstream fish passage at a third dam, and construction of a fish bypass on a dam obstructing a major tributary is anticipated to increase passage of and improve habitat connectivity for both diadromous and resident fishes. We captured 61 837 fish of 35 species in the Penobscot River and major tributaries, through 114 km of boat electrofishing. Patterns of fish assemblage structure did not change considerably during our sampling; relatively few species contributed to seasonal and annual variability within the main‐stem river, including smallmouth bass Micropterus dolomieu, white sucker Catostomus commersonii, pumpkinseed Lepomis gibbosus, and golden shiner Notemigonus crysoleucas. However, distinct fish assemblages were present among river sections bounded by dams. Many diadromous species were restricted to tidal waters downriver of the Veazie Dam; Fundulus species were also abundant within the tidal river section. Smallmouth bass and pumpkinseed were most prevalent within the Veazie Dam impoundment and the free‐flowing river section immediately upriver, suggesting the importance of both types of habitat that supports multiple life stages of these species. Further upriver, brown bullhead Ameiurus nebulosus, yellow perch Perca flavescens, chain pickerel Esox niger, and cyprinid species were more prevalent than within any other river section. Our findings describe baseline spatial patterns of fish assemblages in the Penobscot River in relation to dams with which to compare assessments after dam removal occurs. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
Most of the United States' 2.5 million dams are not under the jurisdiction of any public agency. These small (under 6 ft [1.83 m] tall) nonjurisdictional dams, unregulated and not inventoried anywhere, endanger public safety and degrade riparian ecosystems. Their problems are increasing as structures age and storm events become more violent. Property owners can be held liable for problems at dams. Through several policy changes and legal actions, states can vastly improve the situation. States should consider expanded jurisdiction over small dams, a program of inventorying and mapping all dams in state waterways, owner education and outreach, and shared resources to allow for improved public safety and river restoration through best dam management or dam removal practices. This article is categorized under:
- Human Water > Water Governance
- Engineering Water > Planning Water
- Water and Life > Stresses and Pressures on Ecosystems
14.
我国水电站大坝事故分析与安全对策 总被引：7，自引：0，他引：7
邢林生 《水利水电科技进展》2001,21(2):26-32
对水电站大坝事故的反馈分析表明 ,大多数事故与设计阶段的失误、施工过程遗留下的隐患、运行管理中的差错等因素有关 .应强化设计、施工、运行全过程的风险意识和安全管理 .对运行中的大坝要坚持实施定期检查 ,及时维修加固和改造 ,认真进行安全注册 ,严密制定汛期和低水位时的防范措施 ,加大科研力度和开展险情预计 ,以防止重大事故的突然发生 . 相似文献
15.
Philip M. Harrison Taylor Ward Dirk A. Algera Brad Culling Ted Euchner Alf Leake James A. Crossman Steven J. Cooke Michael Power 《河流研究与利用》2020,36(7):1033-1045
Potadromous salmonids that reside in hydropower reservoirs often have a high recreational and conservation value. However, the potential seasonal turbine entrainment vulnerability patterns of potadromous salmonids are not well understood. Here, we use acoustic telemetry to test the hypothesis that adults of two species of the Salvelinus genus (bull trout and lake trout) differ in their seasonal patterns of entrainment and entrainment vulnerability over a 2‐year period. Our results show that while both species were entrained at similarly low annual rates (~1%), these two salmonids differed in their patterns of forebay residency and proximity, with implications for entrainment risk. Bull trout occupied the forebay at low rates across all seasons, with no clear seasonal pattern of forebay proximity. In contrast, lake trout displayed a strongly seasonal pattern of entrainment vulnerability with a distinct movement away from the forebay during the summer, and a large increase in forebay proximity and use in the winter and spring. These findings provide a novel species‐specific demonstration of the potential entrainment vulnerability of lake trout. The seasonal patterns of entrainment vulnerability seen in previous bull trout studies, where bull trout occupied top pelagic predator niches, were not replicated in our study where bull trout occur in sympatry with another top pelagic predator. These findings, which indicate that species composition plays an important role determining entrainment vulnerability, have important implications for the conservation of indigenous lake trout and bull trout populations, and together highlight the need for a site‐specific approach to entrainment quantification. 相似文献
16.
17.
我国小水电发展战略研究 总被引：8，自引：0，他引：8
我国小水电资源十分丰富，可开发量达8700万kW。经过几十年的开发建设，截至2000年底，全国已建成小水电电站4万多座，装机达2485万kW，根据目前小水电的开发现状以及存在的问题，我国小水电的发展战略是：加快小水电开发，满足边远山区，民族地区和革命老区人民生产生活用电需求，实施小水电代柴，促进退耕还林还草，促进江河治理，改善农业基础设施，以农村电气化带动农村工业化和城镇化，改善生态，保护环境，为可持续发展战略服务。 相似文献
18.
Nonwadeable rivers are unique ecosystems that support high levels of aquatic biodiversity, yet they have been greatly altered by human activities. Although riverine fish assemblages have been studied in the past, we still have an incomplete understanding of how fish assemblages respond to both natural and anthropogenic influences in large rivers. The purpose of this study was to evaluate associations between fish assemblage structure and reach‐scale habitat, dam, and watershed land use characteristics. In the summers of 2011 and 2012, comprehensive fish and environmental data were collected from 33 reaches in the Iowa and Cedar rivers of eastern‐central Iowa. Canonical correspondence analysis (CCA) was used to evaluate environmental relationships with species relative abundance, functional trait abundance (e.g. catch rate of tolerant species), and functional trait composition (e.g. percentage of tolerant species). On the basis of partial CCAs, reach‐scale habitat, dam characteristics, and watershed land use features explained 25.0–81.1%, 6.2–25.1%, and 5.8–47.2% of fish assemblage variation, respectively. Although reach‐scale, dam, and land use factors contributed to overall assemblage structure, the majority of fish assemblage variation was constrained by reach‐scale habitat factors. Specifically, mean annual discharge was consistently selected in nine of the 11 CCA models and accounted for the majority of explained fish assemblage variance by reach‐scale habitat. This study provides important insight on the influence of anthropogenic disturbances across multiple spatial scales on fish assemblages in large river systems. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
19.
The World Commission on Dams (WCD) was a global environmental governance forum that worked between 1998 and 2000 to try to resolve long‐standing controversies between supporters and opponents of large dams. Its objectives were to assess the development effectiveness of large dams and to develop best practice guidelines for large dam construction and management, based on an extensive review of scientific evidence and wide‐ranging stakeholder consultation. This paper reviews literature discussing the WCD, to understand its influence on the debate on large dams and beyond. We find that its influence is debated within four main contexts: (a) interpretations of stakeholder responses to the WCD report and recommendations; (b) the persistence of the kinds of impacts of large dams that gave rise to the Commission's work; (c) the different visions for appropriate follow‐up strategies; and (d) insights from the WCD experience in the context of global environmental governance. Within these four contexts, we identify diverse opinions and directions of post‐WCD development and sources of disagreement on its merits and legacy, ranging from calls for its full implementation to dismissal and opposition. Commentators also differ in their assessment of whether the WCD sparked truly novel insights and propositions for dam decision‐making or whether it simply represented one among many other elements in the broader debate on dams. Most commonly, the WCD's work is cited in the context of persistent negative social and environmental impacts of dams: neither the impacts nor the controversy over large dams have ended. This article is categorized under:
- Engineering Water > Planning Water
- Engineering Water > Sustainable Engineering of Water
20.
小水电优化调度文化进化算法研究及应用 总被引：1，自引：1，他引：0
文化进化算法(MA)是基于人类社会文化知识演变过程的新算法,它模拟微观种群与宏观信仰知识两个层面的进化,通过模拟人类社会文化进化机制实现文化空间的进化与更新,并通过上层文化空间的经验知识指导下层群体的进化搜索方向及步长,最终形成双演化双促进的机制.将文化进化算法应用于求解小水电优化调度数学模型,用Matlab编程实例仿真,结果表明用此算法求解小水电调度优化问题是可行的.经比较,文化进化算法的搜索性能优于遗传算法(GA)和混合遗传算(HGA)等,是一个值得研究的方向. 相似文献
