This paper presents calibration of a catchment water quality model for continuous simulation of the water quality parameters from a catchment to the catchment outlet. The model is an integration of two sub-models: the hydrologic model and the water quality model. The hydrologic model estimates the amount of surface water runoff generated from the catchment during the storm event/ events. The water quality model estimates the transportation of the pollutants (total nitrogen, total phosphorus and suspended solids) from a particular catchment. The water quality model integrates two sub-processes: pollutants build-up and pollutants wash-off. The model calculates separate build-up and wash-off from pervious and impervious catchment surfaces. Rainfall and water quality data were collected for the Hotham creek catchment in Gold Coast, Australia. Runoff calculations from hydrologic model were compared with calculated discharges through widely used Australian models WBNM and DRAINS. Finally, based on measured water quality data, model water quality parameters were calibrated for the above-mentioned catchment.
Keywords: model parameters, water quality, total nitrogen, total phosphorus, hydrologic model, build-up and wash-off