Modelling Management Criteria for On-Site Pollution Control: Flow Rate and Volume-Based Approaches
Résumé
While the need for on-site stormwater and pollution control is generally well accepted by both scientists and practitioners, there is no real agreement yet on management or design criteria to be given to developers for implementation of most suitable runoff control practices. Hydrologic criteria, directly related to stormwater facility's sizing, may for instance usually either be expressed as flow rate or volume targets. Although these criteria are usually assumed to provide adequate runoff and pollution control, their comparison has only received scant attention and determining optimal values for both volume and flow rate targets probably remains difficult for most practitioners. The methodology presented here, therefore, aims to investigate the suitability of different flow rate and volume-based stormwater management options for on-site pollution control. Flow rate control and runoff volume reduction strategies have been simulated (over a 15-year period) with a relatively simple conceptual pervious-best management practice (pervious-BMP) model for different urban streets. First results indicated that permanent retention of relatively small runoff volumes could result in significant reduction of pollutant loads discharged to the environment, although BMPs' performance may be quite sensitive to pollutant wash-off dynamics.