Fergus C Emi, Brooks J Renée, Kaufmann Philip R, Pollard Amina I, Herlihy Alan T, Paulsen Steven G, Weber Marc H
Oak Ridge Institute for Science and Education, U.S. Environmental Protection Agency, Corvallis, OR.
U.S. Environmental Protection Agency, Pacific Ecological Systems Division, Corvallis, OR.
Ecol Indic. 2021 Jan 1;122. doi: 10.1016/j.ecolind.2020.107241.
Lakes face multiple anthropogenic pressures that can substantially alter their hydrology. Dams and land use in the watershed (e.g., irrigated agriculture) can modify lake water regimes beyond natural ranges, and changing climate may exacerbate anthropogenic stresses on lake hydrology. However, we lack cost-effective indicators to quantify anthropogenic hydrologic alteration potential in lakes at regional and national extents. We developed a framework to rank lakes by the potential for dams and land use to alter lake hydrology (HydrAP) that can be applied at a national scale. The HydrAP framework principles are that 1) dams are primary drivers of lake hydro-alteration, 2) land use activities are secondary drivers that alter watershed hydrology, and 3) topographic relief limits where land use and dams are located on the landscape. We ranked lakes in the United States Environmental Protection Agency National Lakes Assessment (NLA) on a HydrAP scale from zero to seven, where a zero indicates lakes with no potential for anthropogenic hydro-alteration, and a seven indicates large dams and/or intensive land use with high potential to alter lake hydrology. We inferred HydrAP population distributions in the conterminous US (CONUS) using the NLA probabilistic weights. Half of CONUS lakes had moderate to high hydro-alteration potential (HydrAP ranks 3-7), the other half had minimal to no hydro-alteration potential (HydrAP ranks 0-2). HydrAP ranks generally corresponded with natural and man-made lake classes, but >15% of natural lakes had moderate to high HydrAP ranks and 10% of man-made lakes had low HydrAP ranks. The Great Plains, Appalachians, and Coastal Plains had the largest percentages (>50%) of high HydrAP lakes, and the West and Midwest had the lowest percentages (30%). Water residence time (τ) and water-level change were associated with HydrAP ranks, demonstrating the framework's intended ability to differentiate anthropogenic stressors that can alter lake hydrology. Consistently across ecoregions high HydrAP lakes had shorter τ. But HydrAP relationships with water-level change varied by ecoregion. In the West and Appalachians, high HydrAP lakes experienced excessive water-level declines compared to low-ranked lakes. In contrast, high HydrAP lakes in the Great Plains and Midwest showed stable water levels compared to low-ranked lakes. These differences imply that water management in western and eastern mountainous regions may result in large water-level fluctuations, but water management in central CONUS may promote water-level stabilization. The HydrAP framework using accessible, national datasets can support large-scale lake assessments and be adapted to specific locations where data are available.
湖泊面临着多种人为压力，这些压力会极大地改变其水文状况。流域内的水坝和土地利用（如灌溉农业）可使湖泊水位变化超出自然范围，而气候变化可能会加剧人为因素对湖泊水文的压力。然而，我们缺乏具有成本效益的指标来量化区域和国家范围内湖泊的人为水文变化潜力。我们开发了一个框架，根据水坝和土地利用改变湖泊水文的潜力对湖泊进行排名（HydrAP），该框架可应用于国家层面。HydrAP框架的原则是：1）水坝是湖泊水文变化的主要驱动因素；2）土地利用活动是改变流域水文的次要驱动因素；3）地形起伏限制了土地利用和水坝在景观中的位置。我们根据HydrAP等级（从0到7）对美国环境保护局国家湖泊评估（NLA）中的湖泊进行了排名，其中0表示没有人为水文变化潜力的湖泊，7表示大型水坝和/或高强度土地利用且具有高改变湖泊水文潜力的湖泊。我们利用NLA概率权重推断美国本土（CONUS）的HydrAP总体分布。美国本土一半的湖泊具有中度至高水文变化潜力（HydrAP等级为3 - 7），另一半具有最小至无水文变化潜力（HydrAP等级为0 - 2）。HydrAP等级通常与天然和人工湖泊类别相对应，但超过15%的天然湖泊具有中度至高HydrAP等级，约10%的人工湖泊具有低HydrAP等级。大平原、阿巴拉契亚山脉和沿海平原拥有高HydrAP等级湖泊的比例最大（>50%），而西部和中西部地区的比例最低（约30%）。水体停留时间（τ）和水位变化与HydrAP等级相关，这表明该框架能够区分可改变湖泊水文的人为压力源。在各个生态区域，高HydrAP等级的湖泊τ始终较短。但HydrAP与水位变化的关系因生态区域而异。在西部和阿巴拉契亚山脉，与低等级湖泊相比，高HydrAP等级的湖泊水位过度下降。相比之下，与低等级湖泊相比，大平原和中西部地区高HydrAP等级的湖泊水位较为稳定。这些差异表明，西部和东部山区的水资源管理可能导致较大的水位波动，而美国本土中部的水资源管理可能促进水位稳定。利用可获取的国家数据集的HydrAP框架可支持大规模湖泊评估，并可适用于有数据的特定地点。
