Dynamic modelling of roadside gully pots during wet weather

Roadside gully pots form a common and important part of many surface water drainage networks. Their primary function is to retain larger solids from road runoff in order to minimise the problems associated with sediment deposition in downstream drainage structures and receiving waters. Typical processes occurring in pots during wet weather are dilution, dispersion, sedimentation, sediment bed build-up and erosion, washout of suspended and dissolved pollutants from the pot liquor and reaeration of the pot liquor. A dynamic water quality model has been developed to simulate these processes. To study the pollutant washout patterns and sludge bed erosion, simulated wet weather tests were carried out on pots draining six different types of roads. Results corroborated earlier findings and were used to successfully calibrate and verify the model.