Development and application of a catchment scale diffuse nitrate modelling tool

Water pollution from diffuse sources is a problem of increasing concern. Efforts to control diffuse pollution have been confined mainly to agricultural land and forests. Little attention has been paid to sources of diffuse pollution from urban areas. A diffuse nitrate modelling tool (DNMT) has been developed for modelling the fate of nitrate in urban areas. This tool works at the catchment scale and has a modular structure that consists of three components: the hydrological module, the nitrogen cycle module and the nitrate transport module. The hydrological model describes the possible flow pathways. The nitrogen cycle model accounts for the mass balance of nitrate and calculates the amount of nitrate for potential loss. The nitrate transport module simulates the movement of nitrate within and from the soil to the receiving water. This paper demonstrates the development of the tool and its application in the White Cart Water catchment. This implementation of the tool shows that it has a good capability for simulating the fate of nitrate in urban catchments. Copyright © 2005 John Wiley & Sons, Ltd.