Optimal volume of non-point sources management detention considering spatio-temporal variability of land surface moisture condition

Abstract

This study presents the method to estimate the optimal volume of a non-point sources (NPS) management detention considering spatio-temporal variability of urban land surface moisture condition. In order to consider statistical characteristics of rainfall events, 3-parameter mixed exponential probability density function (PDF) is applied, and rainfall events are transformed to runoff events through Natural Resources Conservation Service-curve number method. Urban drainage catchment is divided into square-type grid cells, where runoff curve number is estimated by cells. Using the analytical model developed previously with derived probability distribution theory, the PDF of rainfall event depth is transformed to the PDF of stormwater depth. By cells, in consideration of changes in antecedent soil moisture condition and spatial variations in CN of drainage catchment, stormwater capture curve that can represent the drainage area is drawn and from which the optimal volume of a NPS management detention is estimated.