How Does Flow Alteration Propagate Across a Large, Highly Regulated Basin? Dam Attributes, Network Context, and Implications for Biodiversity
How Does Flow Alteration Propagate Across a Large, Highly Regulated Basin? Dam Attributes, Network Context, and Implications for Biodiversity
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DOI：
10.1029/2021ef002490
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发表时间：
2022-06-01
期刊：
影响因子：
8.2
通讯作者：
Sankarasubramanian，A.
中科院分区：
文献类型：
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作者：
Ruhi，Albert;Hwang，Jeongwoo;Sankarasubramanian，A.
大型水坝是河流生态系统退化的主要原因。虽然水坝在河流网络中具有下游水流的累积效应，但大多数水流改变研究都集中在单个水坝的局部影响上。在这里，我们研究了高度管制的科罗拉多河流域（CRB），以了解流量变化如何在河流网络中传播，受到水坝的位置和特性以及河流网络的结构（包括支流的存在）的影响。我们使用了一个空间马尔可夫网络模型，该模型由117个上下游月流量序列（2003-2017年）提供信息，以估计84个中大型大坝的流量变化，这些大坝占CRB总蓄水量的83%以上。使用最小绝对收缩和选择算子回归，然后我们研究了流量变化如何受到当地大坝特性的影响（例如，目的、存储容量）和网络级属性（例如，位置，上游累积存储）。流量变化在整个网络中变化很大，但往往在下游积累，并在主干中保持较高水平。大坝影响更多地由网络级属性（63%）而不是当地大坝属性（37%）来解释，这强调了在评估大坝影响时需要考虑网络背景。高影响水坝通常位于具有高水平的本地鱼类生物多样性、鱼类濒危或需要季节性水流的物种不再存在的子流域。这三个生物多样性方面，以及无坝下游栖息地的数量，表明通过控制流量释放恢复河流生态系统的潜力。我们的方法是可移植的，可以指导筛选大坝重新运行在其他高度管制的流域。
Large dams are a leading cause of river ecosystem degradation. Although dams have cumulative effects as water flows downstream in a river network, most flow alteration research has focused on local impacts of single dams. Here we examined the highly regulated Colorado River Basin (CRB) to understand how flow alteration propagates in river networks, as influenced by the location and characteristics of dams as well as the structure of the river network—including the presence of tributaries. We used a spatial Markov network model informed by 117 upstream‐downstream pairs of monthly flow series (2003–2017) to estimate flow alteration from 84 intermediate‐to‐large dams representing >83% of the total storage in the CRB. Using Least Absolute Shrinkage and Selection Operator regression, we then investigated how flow alteration was influenced by local dam properties (e.g., purpose, storage capacity) and network‐level attributes (e.g., position, upstream cumulative storage). Flow alteration was highly variable across the network, but tended to accumulate downstream and remained high in the main stem. Dam impacts were explained by network‐level attributes (63%) more than by local dam properties (37%), underscoring the need to consider network context when assessing dam impacts. High‐impact dams were often located in sub‐watersheds with high levels of native fish biodiversity, fish imperilment, or species requiring seasonal flows that are no longer present. These three biodiversity dimensions, as well as the amount of dam‐free downstream habitat, indicate potential to restore river ecosystems via controlled flow releases. Our methods are transferrable and could guide screening for dam reoperation in other highly regulated basins.