The New York City Department of Environmental Protection (DEP) is undertaking a number of projects aimed at improving water quality in the Gowanus Canal. Several of these projects are intended to reduce combined sewer overflows (CSOs) into the canal. CSOs are prone to occur during heavy rains when stormwater overwhelms the capacity of the local sewer system.Because Prospect Heights is part of the watershed for the Gowanus Canal, DEP plans to install a network of bioswales to absorb stormwater. Bioswales are tree pits with a curb cut to absorb runoff. This map shows the locations of approximately 40 bioswales to be created in Prospect Heights (marked by green dots).