Streets or Basements? Where Do You Prefer Your Stormwater?

The Village of Lincolnwood is developing a storm water management program to reduce basement backups by taking advantage of the relatively flat terrain to use the streets to store and attenuate storm runoff before it enters the combined sewers. Flows entering the sewer system will be regulated by placing restrictors in catch basins and inlets while surface storage is managed through the use of containment berms.A detailed hydrologic / hydraulic model of the collection system was constructed to evaluate optimal sizing and placement of berms and restrictors. By dynamically simulating both one-dimensional sewer flows and two-dimensional overland flows, engineers were able to predict the extent and depth of surface flooding and sewer surcharging and make adjustments to the placement of berms and restrictors in order to maximize the utilization of available surface storage volume.The model determined, however, that surface storage alone would not be sufficient to provide the desired 10-year level of protection from basement flooding. Therefore a series of conventional stormwater management improvement alternatives have been developed which will provide the desired level of protection.