Argonne National Laboratory, Environmental Science Division, 9700 S. Cass Avenue, Bldg. 240, Argonne, IL, USA,
Environ Monit Assess. 2014 Nov;186(11):7075-95. doi: 10.1007/s10661-014-3912-5. Epub 2014 Aug 17.
Large areas of public lands administered by the Bureau of Land Management and located in arid regions of the southwestern United States are being considered for the development of utility-scale solar energy facilities. Land-disturbing activities in these desert, alluvium-filled valleys have the potential to adversely affect the hydrologic and ecologic functions of ephemeral streams. Regulation and management of ephemeral streams typically falls under a spectrum of federal, state, and local programs, but scientifically based guidelines for protecting ephemeral streams with respect to land-development activities are largely nonexistent. This study developed an assessment approach for quantifying the sensitivity to land disturbance of ephemeral stream reaches located in proposed solar energy zones (SEZs). The ephemeral stream assessment approach used publicly-available geospatial data on hydrology, topography, surficial geology, and soil characteristics, as well as high-resolution aerial imagery. These datasets were used to inform a professional judgment-based score index of potential land disturbance impacts on selected critical functions of ephemeral streams, including flow and sediment conveyance, ecological habitat value, and groundwater recharge. The total sensitivity scores (sum of scores for the critical stream functions of flow and sediment conveyance, ecological habitats, and groundwater recharge) were used to identify highly sensitive stream reaches to inform decisions on developable areas in SEZs. Total sensitivity scores typically reflected the scores of the individual stream functions; some exceptions pertain to groundwater recharge and ecological habitats. The primary limitations of this assessment approach were the lack of high-resolution identification of ephemeral stream channels in the existing National Hydrography Dataset, and the lack of mechanistic processes describing potential impacts on ephemeral stream functions at the watershed scale. The primary strength of this assessment approach is that it allows watershed-scale planning for low-impact development in arid ecosystems; the qualitative scoring of potential impacts can also be adjusted to accommodate new geospatial data, and to allow for expert and stakeholder input into decisions regarding the identification and potential avoidance of highly sensitive stream reaches.
大面积由美国西南部干旱地区土地管理局管理的公共土地正被考虑用于开发大型公用事业规模的太阳能设施。在这些沙漠、冲积山谷进行的土地干扰活动有可能对短暂溪流的水文和生态功能产生不利影响。短暂溪流的监管和管理通常属于联邦、州和地方各级的一系列计划，但在土地开发活动方面保护短暂溪流的基于科学的指导方针基本上还没有。本研究开发了一种评估方法，用于量化位于拟议太阳能区 (SEZ) 的短暂溪流流域对土地干扰的敏感性。短暂溪流评估方法使用了公共可用的水文、地形、地表地质和土壤特征以及高分辨率航空影像的地理空间数据。这些数据集用于告知基于专业判断的潜在土地干扰对短暂溪流的选定关键功能（包括水流和泥沙输送、生态生境价值和地下水补给）的评分指数。总敏感性评分（水流和泥沙输送、生态生境和地下水补给的关键溪流功能评分之和）用于识别高度敏感的溪流流域，以便为 SEZ 中的可开发区域做出决策。总敏感性评分通常反映了各个溪流功能的评分；地下水补给和生态生境则存在一些例外。这种评估方法的主要局限性是缺乏对现有国家水文数据集的短暂溪流通道的高分辨率识别，以及缺乏描述流域尺度上对短暂溪流功能潜在影响的机制过程。这种评估方法的主要优势在于它允许在干旱生态系统中进行低影响开发的流域尺度规划；潜在影响的定性评分也可以进行调整，以适应新的地理空间数据，并允许专家和利益相关者参与关于识别和潜在避免高度敏感溪流流域的决策。
