The deeper the sump, the more effective the stormwater structure and catch basin filters will be both in terms of pollutant removals and reducing frequency of maintenance. More depth in a structure means more quiescence, thus allowing the pollutants a better chance to separate out and the basin drain filter to be more effective. Also, a deeper sump results in less scouring, thus the captured solids are more likely to be retained in the structure with the help of a catch basin trap. Finally, more depth provides more volume, which means fewer cycles between maintenance, which reduces the service cost over the lifetime of the facility.
