Evaluation of Green Infrastructure Designs Using the Automated Geospatial Watershed Assessment Tool

In arid and semi-arid regions, green infrastructure (GI) designs can address several issues facing urban environments, including augmenting water supply, mitigating flooding, decreasing pollutant loads, and promoting greenness in the built environment. An optimum design captures stormwater, addressing flooding and water quality issues, in a way that increases water availability to support natural vegetation communities and landscaping in the built environment. A module was developed for the Automated Geospatial Watershed Assessment (AGWA) tool which supports the design and placement of a suite of GI practices, singularly or in combination, in order to simulate urban hydrology with and without GI features at the household and neighborhood scale.The GI tool takes advantage of the advanced, physically-based infiltration algorithms and geometric flexibility of the Kinematic Runoff and Erosion (KINEROS2) watershed model. The resulting software provides an up-to-date GIS-based GI assessment framework that automatically derives model parameters from widely available spatial data. It is also capable of manipulating GI features within a graphical interface to conveniently view and compare simulation results with and without GI features at a lot, neighborhood or small catchment scale. The new tool was used to assess a variety of GI designs across a subdivision in Sierra Vista, Arizona for the design objectives: maximize stormwater capture, maximize water augmentation, and maximize ecosystem services.