The majority of stormwater runoff in Bend, OR is uniquely managed via a combination of surface water discharge and dispersed infiltration systems. The City of Bend owns and operates over 7,000 dispersed infiltration systems, ranging from 3 to 100 feet deep. These systems are designed to prevent flooding and keep pollutants from impacting surface water quality in the Deschutes River. The City recently delineated its surface water drainage network that conveys stormwater to the River using rudimentary geoprocessing tools available in ArcPro. The workflow was fairly straightforward; utilize a Lidar derived DEM and overlay City infrastructure while incorporating expertise from field personnel to verify the accuracy of the final product. That work prompted a simple question: what are the isolated drainage basins for the dispersed systems that manage the bulk of stormwater City-wide? It became clear that urban hydrology would not be as simple to analyze as previous efforts. Jurisdictional boundaries, complex drainage patterns, and data limitations were only some of the implications that would need to be addressed to reflect the reality of managing stormwater in the high desert. Workflows identified in ESRI’s Arc Hydro guides were modified to fit the region’s unique hydrologic conditions. Ultimately, a data package was developed that is now available to provide data-driven outcomes that serve the community.
