Blue Roof and Combined Sewer Overflow (CSO) prevention

NYC, and in particular Brooklyn, is plagued by a high frequency of combined sewer overflows (CSOs) because of an undersized wastewater treatment system. This undersized condition is partly due to increased usage (treating volumes and flows beyond a design capacity) and due to the intentional design of combining sanitary sewage flows and storm water flows in the same pipeline. When CSO occurs, untreated water is discharged into the Hudson river carrying harmful compounds collected on streets into the water basin. Therefore, pollutants contained into water basins increase putting the environment under threat.
A solution to this problem is the capture of as much precipitation as possible every time it rains. Through a comprehensive blue roof program, I demonstrate herein that having blue roofs on every lot in Brooklyn will eliminate CSO events for rainfall events of less than one inch per day. This would decrease the number of CSO events from an estimated 57 events in 2010 to 25 or fewer events when such a program could be implemented. If this proposal is implemented, not only will pollution be prevented, but NYC would have eliminated the need for multi-million dollar investments to enhance treatment capacity. NYC should use the conclusions of this research to adopt such policy efforts such as a property tax rebate and other incentives for those property owners that install blue roofs.