Field Test of Paved Area Reduction Factors Using a Storm Water Management Model and Water Quality Test Site

Abstract

A water quality research facility located at Parking Lot K on the Auraria campus of the University of Colorado, Denver was used to create a calibrated hydraulic model that represents rainfall and runoff from a small, developed urban watershed. The calibrated model was used to test effective impervious values that have been proposed in previous research. Field tests included a hydraulic model that was calibrated with 3 years of recorded rainfall and runoff data and four case studies. Each case study compared the theoretical development of paved area reduction factors with two types of storm water low-impact development practices, a porous pavement section, and water quality pond. These two types of storm water best management practices have been defined as a conveyance-based and storage-based reduction factors in previous studies. This study found a strong correlation with theoretical reduction factors when they are compared to measured rainfall events and also when design storm distributions are applied to the calibrated field model. Four case studies presented in this paper conclude that the reduction factors presented in previous studies are accurate and applicable to for the Denver, Colorado area. The reduction factors were also tested with more widely used unit hydrograph procedures, and it was found that the reduction factors are accurate for other hydrologic modeling procedures and storm distribution types.