Will Dam Removal Increase Nitrogen Flux to Estuaries?
Will Dam Removal Increase Nitrogen Flux to Estuaries?
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DOI：
10.3390/w8110522
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发表时间：
2016-11-01
期刊：
影响因子：
3.4
通讯作者：
Simpson, Marissa
中科院分区：
文献类型：
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作者：
Gold, Arthur J.;Addy, Kelly;Simpson, Marissa
为了推进大坝拆除科学，需要将功能和效益分析与单个大坝的属性和对下游受水的影响联系起来。我们检查了新英格兰（美国）地区的7550座水坝，以寻找与水坝拆除相关的可能权衡。大坝拆除通常会改善安全或洄游鱼类通道，但可能会增加沿海流域的氮通量和富营养化。我们利用土地利用、河流流量和水文的地理空间数据，用算法估计了N的加载和移除。我们关注的是带有水库的水坝，这些水库增加了河流到达特定点的滞留时间，创造了局部氮去除量增加的热点。根据氮负荷、滞留时间和深度，大约有2200座水库具有去除氮的潜在效益。在整个河流订单中，对这些移氮大坝的安全担忧在28%到44%之间。一级河流是除氮坝的主要组成部分（70%），但只有3%的一级河流被归为高洄游价值。在拆除大坝可能会消除特定水库的氮去除功能的情况下，有必要对特定地点进行分析，以改善氮的输送估计，并检查保留水库同时增强鱼类通道和安全的替代方案。
To advance the science of dam removal, analyses of functions and benefits need to be linked to individual dam attributes and effects on downstream receiving waters. We examined 7550 dams in the New England (USA) region for possible tradeoffs associated with dam removal. Dam removal often generates improvements for safety or migratory fish passage but might increase nitrogen (N) flux and eutrophication in coastal watersheds. We estimated N loading and removal with algorithms using geospatial data on land use, stream flow and hydrography. We focused on dams with reservoirs that increase retention time at specific points of river reaches, creating localized hotspots of elevated N removal. Approximately 2200 dams with reservoirs had potential benefits for N removal based on N loading, retention time and depth. Across stream orders, safety concerns on these N removal dams ranged between 28% and 44%. First order streams constituted the majority of N removal dams (70%), but only 3% of those were classified as high value for fish passage. In cases where dam removal might eliminate N removal function from a particular reservoir, site-specific analyses are warranted to improve N delivery estimates and examine alternatives that retain the reservoir while enhancing fish passage and safety.