Hoghooghi Nahal, Golden Heather E, Bledsoe Brian P, Barnhart Bradley L, Brookes Allen F, Djang Kevin S, Halama Jonathan J, McKane Robert B, Nietch Christopher T, Pettus Paul P
Oak Ridge Institute for Science and Education, c/o US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH 45268, USA.
Institute for Resilient Infrastructure Systems, College of Engineering, University of Georgia, Athens, GA 30602, USA.
Water (Basel). 2018;10(8):991. doi: 10.3390/w10080991. Epub 2018 Jul 27.
Low Impact Development (LID) is an alternative to conventional urban stormwater management practices, which aims at mitigating the impacts of urbanization on water quantity and quality. Plot and local scale studies provide evidence of LID effectiveness; however, little is known about the overall watershed scale influence of LID practices. This is particularly true in watersheds with a land cover that is more diverse than that of urban or suburban classifications alone. We address this watershed-scale gap by assessing the effects of three common LID practices (rain gardens, permeable pavement, and riparian buffers) on the hydrology of a 0.94 km mixed land cover watershed. We used a spatially-explicit ecohydrological model, called Visualizing Ecosystems for Land Management Assessments (VELMA), to compare changes in watershed hydrologic responses before and after the implementation of LID practices. For the LID scenarios, we examined different spatial configurations, using 25%, 50%, 75% and 100% implementation extents, to convert sidewalks into rain gardens, and parking lots and driveways into permeable pavement. We further applied 20 m and 40 m riparian buffers along streams that were adjacent to agricultural land cover. The results showed overall increases in shallow subsurface runoff and infiltration, as well as evapotranspiration, and decreases in peak flows and surface runoff across all types and configurations of LID. Among individual LID practices, rain gardens had the greatest influence on each component of the overall watershed water balance. As anticipated, the combination of LID practices at the highest implementation level resulted in the most substantial changes to the overall watershed hydrology. It is notable that all hydrological changes from the LID implementation, ranging from 0.01 to 0.06 km across the study watershed, were modest, which suggests a potentially limited efficacy of LID practices in mixed land cover watersheds.
低影响开发（LID）是传统城市雨水管理实践的一种替代方案，旨在减轻城市化对水量和水质的影响。地块和局部尺度的研究提供了LID有效性的证据；然而，对于LID实践在整个流域尺度上的影响却知之甚少。在土地覆盖比单纯的城市或郊区分类更为多样的流域中尤其如此。我们通过评估三种常见的LID实践（雨水花园、透水路面和河岸缓冲带）对一个0.94平方公里混合土地覆盖流域水文的影响，来填补这一流域尺度的空白。我们使用了一个名为“土地管理评估生态水文可视化模型”（VELMA）的空间明确生态水文模型，来比较实施LID实践前后流域水文响应的变化。对于LID情景，我们研究了不同的空间配置，使用25%、50%、75%和100%的实施范围，将人行道改造成雨水花园，将停车场和车道改造成透水路面。我们还沿着与农业土地覆盖相邻的溪流应用了20米和40米宽的河岸缓冲带。结果表明，所有类型和配置的LID都会使浅层地下径流、入渗以及蒸散总体增加，而峰值流量和地表径流减少。在各个LID实践中，雨水花园对整个流域水平衡的各个组成部分影响最大。正如预期的那样，最高实施水平的LID实践组合导致整个流域水文变化最为显著。值得注意的是，LID实施带来的所有水文变化，在整个研究流域范围为0.01至0.06平方公里，幅度较小，这表明LID实践在混合土地覆盖流域中的功效可能有限。
