STORMWATER RUNOFF QUALITY IN NEW YORK CITY: PRELIMINARY RESULTS

Runoff water samples were collected and analyzed for Total Suspended Solids, Total nitrogen, Total organic carbon, Total Phosphorus, Total and dissolved metals, Total Dissolved Salts, Total Petroleum Hydrocarbon, and coliform counts as part of a green infrastructure monitoring study in the boroughs of Brooklyn and Queens in New York City. The samples were from 13 sites in Brooklyn and Queens that include 9 streetside (Right-of-Way) bioswales and rain gardens on two parking lots. For most sites, because of the space limitation, a stream- sampler was used. In most cases, runoff samples have been collected three times per year since 2011; a first-flush water sample was also collected in addition to a time-weighed composite. This data is intended for calculating the total solids, contaminants and nutrients that are removed from the sewer or stormwater system due to green infrastructure. Preliminary data shows that the ranges of these parameters in New York City are comparable to what’s found in other major cities (BMP database). There is high variability among sites and individual precipitation events during which the samples were collected.