The Impacts of Dam-Related Flow Regulation on the Physical and Ecological Characteristics of Rivers

大坝流量调节对河流物理和生态特征的影响

• 批准号: 0322850
• 负责人: Francis Magilligan
• 金额: $ 24.43万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0322850&HistoricalAwards=false
• 关键词: Impacts; Dam; Related; Flow; Regulation

Dams generate significant hydrogeomorphic alterations that have profoundly altered and degraded river ecosystems. General agreement exists within the aquatic community that particular nodes or zones within the riparian environment reflect and record disturbance in important ways and become critical bio-indicators of ecological integrity. These aquatic hotspots commonly occur where hydrologic flow paths converge with some fundamental ecological and geochemical component, such as at tributary junctions. Numerous previous studies have chronicled the hydrologic, geomorphic, or ecological impacts of dams, but rarely have these three responses been simultaneously evaluated in a watershed perspective where multiple dams exist. Few comprehensive evaluations exist of the hydrogeomorphic effects of dams that both examine whole watersheds and that encompass an array of dam types and operation strategies. The main goals of this research project are to elevate the analysis of dams away from a primarily singular case study view and to specifically link the ecological impacts of dams to the geomorphic response resulting from these hydrologic changes. Dams fragment watersheds, and the normal spatial suite of geochemical, ecological, and geomorphic processes are greatly disturbed along mainstems and at tributary junctions with the mainstem. This project will evaluate sediment sources and residence times at the event-to-decadal timescale in systems disturbed by multiple dams. The project also will determine the length-scale and magnitude of this disturbance on aquatic ecosystems at the watershed scale. Another main objective of the project is to evaluate how different dam types and management styles generate different sediment fluxes and resulting aquatic ecology. The residence time of this sediment embedded in the channel bed will be documented using short-lived radionuclides, such as 210-Pb and 7-Be. The project focuses directly on the effects of dams on both sediment storage and the residence time of bed sediment and their distinct or combined control on benthic community structure. This research will be conducted on tributaries and mainstem sections of the Upper Connecticut River watershed, a basin with a history of extensive damming and where extensive base data exist. This research has several important scientific and social components. Scientifically, the use of fallout radionuclides has far-reaching implications. There is no known quantitative expression of embeddedness, and these results could establish this technique as the scientific standard not only for studies related to dams but also for fisheries management in general. This research also is expected to have significant benefits for society, as its results will be important for Federal Energy Regulatory Commission (FERC) relicensing and for National Environmental Policy Act (NEPA) compliance. The research results also will help establish the necessary base conditions for adaptive management strategies.

水坝产生了重大的水文地貌变化，深刻地改变和退化了河流生态系统。水生生物界普遍认为，河岸环境中的特定节点或区域以重要方式反映和记录干扰，并成为生态完整性的关键生物指标。这些水生热点通常发生在水文径流与一些基本的生态和地球化学成分交汇的地方，例如在支流交界处。许多以前的研究记录了大坝对水文、地貌或生态的影响，但很少在存在多个大坝的分水岭视角下同时评估这三种反应。很少对大坝的水文地貌影响进行全面评估，这些大坝既检查整个流域，又涵盖一系列大坝类型和运行策略。这一研究项目的主要目标是将对大坝的分析从主要单一的案例研究视角提升，并具体地将大坝的生态影响与这些水文变化引起的地貌反应联系起来。堤坝破碎了分水岭，正常的地球化学、生态和地貌过程的空间组合沿主干和与主干的支流交界处受到极大干扰。该项目将在事件到十年的时间尺度上评估受多个大坝扰动的系统中的泥沙来源和停留时间。该项目还将确定这种干扰在分水岭尺度上对水生生态系统的长度、规模和程度。该项目的另一个主要目标是评估不同的大坝类型和管理方式如何产生不同的泥沙通量和由此产生的水生态。嵌入到河床中的这种沉积物的停留时间将使用短寿命放射性核素，如210-铅和7-Be进行记录。该项目直接侧重于水坝对底泥储存和底泥停留时间的影响，以及它们对底栖群落结构的不同或联合控制。这项研究将在康涅狄格河上游流域的支流和主干部分进行，该流域有广泛的筑坝历史，并有大量的基础数据。这项研究有几个重要的科学和社会组成部分。从科学上讲，放射性尘埃的使用具有深远的影响。目前还没有已知的嵌入性的定量表达，这些结果可能使这项技术不仅成为与大坝有关的研究的科学标准，而且也作为一般渔业管理的科学标准。这项研究预计也将为社会带来重大好处，因为其结果将对联邦能源管理委员会(FERC)的重新许可和国家环境政策法案(NEPA)的遵守至关重要。研究结果也将有助于为适应性管理战略建立必要的基础条件。