National framework for ranking lakes by potential for anthropogenic hydro-alteration

• Published in: Ecological indicators 2021-03, Vol.122 (C), p.107241, Article 107241
• Main Authors: Fergus, C. Emi, Brooks, J. Renée, Kaufmann, Philip R., Pollard, Amina I., Herlihy, Alan T., Paulsen, Steven G., Weber, Marc H.
• Format: Article
• Language: English
• Subjects: Anthropogenic stressors; Hydrologic alteration indicator; Lake water balance; Regional and national assessments; Water-level fluctuations
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2020.107241

•US lakes ranked on gradient of hydro-alteration potential using dam & land use data.•50% of US lakes have dams & land use with great potential to alter lake hydrology.•HydrAP rank associations with lake water-level change varied by ecoregion.•West and Appalachians lakes with high HydrAP ranks had large water-level change.•HydrAP provides tool to evaluate anthropogenic drivers of lake hydro-alteration.•Lakes with no potential for human hydro-alteration decreased from 2007 to 2012. 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. High HydrAP