Ecological and Best Management Practices Planning to Address Combined Sewer Overflows in New York City

摘要

Water quality in New York Harbor is currently impacted by combined sewage and stormwateroverflows during rain events. As part of the Mayor’s PlaNYC 2030 program, New York CityEnvironmental Protection (NYCDEP) is spearheading the Ecological and Best ManagementPractices (BMPs) Planning to Address Combined Sewer Overflows (CSOs) initiative. Amongthe ecological pilots being implemented are algal turf scrubbers and constructed ribbed musselbeds, oyster habitat reefs, and eelgrass beds. They will be monitored for potential water qualityimprovements in New York Harbor. NYCDEP is also currently piloting innovative and longtermsustainable source controls to evaluate their effectiveness in reducing the quantity ofstormwater runoff entering the sewer system in various types of ultra-urban environments. TheseBMP pilots are located within highway medians, park-and-ride lots, public parks, street-sidesidewalks, and public housing facilities throughout the City. The stormwater pilots beingimplemented and monitored include enhanced tree pits, stormwater infiltration swales,bioretention cells, pervious pavements, blue roofs, and subsurface retention systems. Flowmeasurements, weather data, and physical observation are being used to evaluate the effect ofthese pilots on storm hydrology. Basic water quality analyses are expected to indicate whetherthese pilots function similarly to BMPs in other regions and to identify potential maintenanceconcerns. Monitoring data for both ecological pilots and BMPs will be collected and analyzedover the course of two years after completion of each pilot construction. This information willultimately be utilized in combination with stormwater modeling efforts to evaluate the impact ofwatershed-level implementation, revise sewer codes and regulations, and develop guidelines forimplementing green-infrastructure throughout the City.