A new algorithm to calculate weighted flow-accumulation from a DEM by considering surface and underground stormwater infrastructure

This study presents a new algorithm, called the Weighted Adaptive Stormwater Infrastructure (WASI) algorithm, to calculate weighted flow-accumulation of surface runoff by considering man-made stormwater infrastructure that modifies natural drainage flow paths across the landscape. The WASI algorithm incorporates ancillary data sets required to determine the depth of effective rainfall (i.e., rate of precipitation plus subsurface return flow, rate of evapotranspiration plus infiltration, duration of rainfall, depth of initial absorption to ground) and a priori information on surface and underground stormwater infrastructure into grid-based hydrologic analysis using a DEM. Using new software, named the WASI surface runoff calculator (implemented as part of this study), the WASI algorithm can be applied to urban and suburban areas where both surface and underground stormwater infrastructure is installed. This paper describes the concept and details of the WASI algorithm, as well as its applications to synthetic and real-world data sets which revealed that the new software can provide more accurate hydrologic information than other commercial GIS software such as IDRISI and ArcGIS.

► The WASI algorithm that calculates weighted flow-accumulation by considering man-made stormwater infrastructure is presented.
► New software named the WASI surface runoff calculator, is developed and can be applied to urban and suburban areas.
► New software can provide more accurate hydrologic information than other commercial GIS software such as IDRISI and ArcGIS.