Relating Effluent Control Parameters to River Quality Objectives Using a Generalised Catchment Simulation Model

A computer model has been developed which combines a simulation based approach with the modular logic of the steady-state catchment approach, and provides facilities for calibration and verification of simulated data against observed data. Temporal correlation of simulated variables (e.g. flow and concentration) is also possible. This model has been used to study the River Wey basin with a view to assessing the impact of twelve significant sewage effluent discharges upon the river, to identify where action is needed to restore and maintain the quality of the River Wey and its tributaries, and to seek a solution combining the various options of revising sewage works' operating targets and making improvements to works' performance. This study having been completed, the preferred options have been identified and are being put forward for discussion within the Authority.