Long-term prediction of water quality for three types of catchment

A simple dynamic model relating the temporal change of the total mass of chemicals in a catchment to the chemical loading in the river provides high-accuracy predictions of absolute and time-integrated chemical loads. The developed model is able to reproduce effectively and simultaneously for all considered time scales the observed hysteresis in the relationship between chemical concentration in stream water and river discharge. Three types of catchment have been examined for long-term modelling: a local urban streamwater catchment, a transition urban-agricultural catchment and a large catchment with varied land use (urban, agricultural and protected forested areas). The long-period changes in model parameters and in water-quality variables are determined for each catchment.