Development of a long-term nonprint pollution model for water quality management in small to medium watersheds

Abstract

The present study attempted to develop mathematical KONDI(KOrea Nonpoint Discharge and impact) model and integrated computer simulation packages to simulate runoff, nonpoint pollutant discharge, and the impact of nonpoint pollutant to lake water quality for long period. KONDI model is an integrated model operates on a daily time step and directly predict the influence of upland nonpoint pollutant to lake water quality. This model simulates water balance on a daily basis by incorporating the processes of evapotranspiration and soil water redistribution resulting from meteorological variations. Daily surface runoff and peak runoff are calculated in hydrology module and nonpoint pollutant is calculated using loading function with sediment. Lake impact is calculated using phosphorus mass balance. This model has been calibrated and verified by application to Hoedong Lake watershed. The model``s predictions and observed daily water runoff and lake phosphorus concentration compared favorably. The model``s strengths are shown to be flexible computational structure, a minimum of regionally specific code and a representation based on hydrologic and dyfraulic processes. This physically based model allows management alternative changes to be reflected in physically predictable parameters and by weather data simulation.