Identifying Urban Watershed Boundaries and Area, Fairfax County, Virginia

Abstract Urban hydrology differs from that of natural environments, and thus urban watersheds require innovative evaluation techniques. Typical geospatial evaluation of urban hydrology begins with identification of water flow and watershed boundaries. This study identifies steps to delineate a highly urbanized watershed in Fairfax County, Virginia. Using standard techniques for natural watersheds and one-meter2 resolution lidar, watershed and flow accumulation raster datasets were derived. Then, modifications encountered within urban landscapes i.e., impervious surfaces, stormwater inlets, pipes, and retention ponds along with high-resolution aerial photos and lidarderived contour lines were integrated into the analysis. Regions redirecting water flow from stream channels and areas redirecting water flow into the stream channels were identified. These areas were removed or added, reducing the area by almost 17 percent, and the watershed boundary was significantly altered. This analysis illustrates the significance of the distinctive characteristics of the urban landscape in accurate delineations of urban watersheds.

[1]  Martin M. Kaufman,et al.  Urban Watersheds: Geology, Contamination, and Sustainable Development , 2011 .

[2]  Budhendra L. Bhaduri,et al.  Long-Term Hydrologic Impact of Urbanization: A Tale of Two Models , 2001 .

[3]  Julien Lhomme,et al.  Applying a GIS-based geomorphological routing model in urban catchments , 2004 .

[4]  Thomas Debo,et al.  Municipal Stormwater Management, Second Edition , 2002 .

[5]  Akira Kawamura,et al.  Development and testing of a distributed urban storm runoff event model with a vector-based catchment delineation , 2012 .

[6]  David J. Sample,et al.  Geographic Information Systems, Decision Support Systems, and Urban Storm-Water Management , 2001 .

[7]  U. Hatch,et al.  Watershed Retrofit and Management Evaluation for Urban Stormwater Management Systems in North Carolina , 2010 .

[8]  E. Terrence Slonecker,et al.  Remote sensing of impervious surfaces: A review , 2001 .

[9]  Robert Pitt,et al.  Stormwater Effects Handbook: A Toolbox for Watershed Managers, Scientists, and Engineers , 2001 .

[10]  M. B. McPherson,et al.  Problems in modeling urban watersheds , 1974 .

[11]  Fabrice Rodriguez,et al.  A distributed hydrological model for urbanized areas - Model development and application to case studies , 2008 .

[12]  Wolfgang Rauch,et al.  Comparison of two model based approaches for areal rainfall estimation in urban hydrology , 2014 .

[13]  Robert G. Traver,et al.  Improving Urban Stormwater Quality: Applying Fundamental Principles , 2010 .

[14]  Robert G. Traver,et al.  Integration of Education, Scholarship, and Service through Stormwater Management , 2010 .

[15]  H. Andrieu,et al.  Surface runoff in urban catchments: morphological identification of unit hydrographs from urban databanks , 2003 .