Stormwater source control regulation: a hydrological comparison of alternative policies

Stormwater source control regulations are rapidly diffusing in many countries. Most of these are provisions that limit runoff rates at the parcel-scale, although some references indicate some negative side effects, at the catchment-scale, for this form of regulation. In this paper, we compare, at that scale, the effects of several runoff rate and runoff volume provisions, using a hydrological model calibrated on a real catchment in the Paris region. We considered two main objectives: to avoid sewer overflows and to preserve receiving waters. The results show that runoff volume provisions are more effective in terms of receiving waters preservation than the runoff rate ones. In terms of sewer overflows, both can reach the same performances.