Disaggregated streamflow approach for improving water-quality modeling

Traditional hydrologic models employ a rainfall-runoffmodeling approach in which the accuracy of the results is largely dependent upon the ability to minimize the temporal and spatial errors associated with the rainfall data. The current paper examines the feasibility of using an alternative approach in which observed streamflow time series are disaggregated into baseflow, point source, and nonpoint source time series, which are then used as forcing functions to generate point and nonpoint source pollution load predictions. The potential utility of the approach is examined by comparing the results of four different watershed simulations against results obtained from the traditional approach using an Loading Simulation Program C (LSPC) model with standard statistical tests for both calibration and validation analyses. The disaggregation approach was found to yield superior results to that obtained using the traditional approach.