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Representing Green Infrastructure Management Techniques in Arid and Semi-arid Regions: Software Implementation and Demonstration using the AGWA/KINEROS2 Watershed Model
Citation:
Korgaonkar, Y., I. Burns, D. Guertin, D. Goodrich, C. Unkrich, J. Barlow, AND W. Kepner. Representing Green Infrastructure Management Techniques in Arid and Semi-arid Regions: Software Implementation and Demonstration using the AGWA/KINEROS2 Watershed Model. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/329, 2014.
Impact/Purpose:
This work provides environmental protection managers and practitioners with an ability to evaluate a selected set of Green Infrastructure (GI) features relative to low impact development in arid and semi-arid regions. Specifically, the Automated Geospatial Watershed Assessment (AGWA) hydrologic modeling and watershed assessment tool has been modified to help facilitate environmental assessment related to GI practices at multiple scales (lot, subdivision, and small watershed). The AGWA GI tool can be a used to inform planning decisions related to urban development and storm water management and will be useful in understanding expected differences in storm water runoff between neighboring developments or natural environments.
Description:
Increasing urban development in the arid and semi-arid regions of the southwestern United States has led to greater demand for water from a region of limited water resources which has fundamentally altered the hydrologic response of developed watersheds. Green Infrastructure (GI) practices are being widely adopted to mitigate the impacts of development on water quantity and quality. However, Geographic Information System (GIS)-based watershed tools that operate from the lot-to-subdivision-to-watershed level for rapid GI planning assessments are lacking. The Automated Geospatial Watershed Assessment (AGWA) tool was modified to allow the design and placement of a small set of GI practices in order to simulate urban hydrology with and without GI features. This software development effort was undertaken to take advantage of the advanced, physically-based infiltration algorithms and geometric flexibility of the Kinematic Runoff Erosion (KINEROS) 2 watershed model. The resulting software provides an up-to-date GIS GI assessment framework that automatically derives model parameters from widely available spatial data. It is also capable of manipulating GI features and simulating at the lot scale within a graphical interface to conveniently view and compare simulation results with and without GI features. These features distinguish the approach presented herein from existing GI hydrology tools. The AGWA GI software was then tested at the lot level with and without GI features to ensure programming integrity and hydrologically sound results. Further testing was conducted at the subdivision level without GI features as high-resolution rainfall-runoff observations were available from a subdivision in Sierra Vista, Arizona. This testing also confirmed programming integrity and the capability to realistically simulate urban hydrology. A set of case study simulations was then conducted for the Sierra Vista subdivision with various combinations of the implemented GI features. Results indicate that the resulting software was robust at the lot, subdivision, and small watershed level and it can realistically represent and simulate storm runoff responses for the selected GI features. The AGWA GI tool offers a foundation for the incorporation of a broader array of GI features.