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原文传递 Engineering and Ecological Aspects of Dam Removal-An Overview.

题名：	Engineering and Ecological Aspects of Dam Removal-An Overview.
作者：	conyngham, j. fischenich, j. c. white, k. d.
关键词：	density, removal, communities, aging(materials), floods, civil engineering, cost benefit analysis, infrastructure, cards, farms, conservation, rivers, biology, reports, high density
摘要：	Decommissioning and removing dams has emerged as one of the central foci of the new millennium for infrastructure management, river conservation, and the restoration of fisheries populations (American Institute of Biological Sciences (AIBS) 2002; Heinz Center 2002). Anadromous, catadromous, and adfluvial species (Figure 1) are especially impacted by dam decommissioning and removal. It represents arguably the most powerful tool and largest opportunity for restoration of aquatic ecosystems and communities that currently exists. Several phenomena underlie this development: ' High dam densities and the aging of dam infrastructure. Of large dams, 85 percent will have exceeded their design lifespans by 2020 or soon thereafter (Federal Emergency Management Agency (FEMA) 2001). Though inventories are poor, dams exist at much higher densities than many realize (Figure 2). ' Threats or occurrences of dam failures (Figures 3, 4, 5). In 2000 and 2001, 520 dam incidents and 61 dam failures occurred; the American Society of Civil Engineers (ASCE) gave dam management and safety a grade of D in the last two editions of its Report Card for America's Infrastructure (ASCE 2002). / Supplementary Notes: The original document contains color images. / Availability Note: Product reproduced from digital image. Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0716；10p
报告类型：	科技报告