Citation:

OCONNOR, T. MONITORING OF A BEST MANAGEMENT PRACTICE POND IN THE STATEN ISLAND BLUEBELL. Presented at New York Water Environment Association (NYWEA) 78th Annual Meeting, New York City, NY, February 05 - 08, 2006.

Impact/Purpose:

To inform the public

Description:

The USEPA's Urban Stormwater Management Branch has monitored stormwater drainage and best management practices (BMP) as part of its research program. One BMP being monitored, a wetland/retention pond, is in the Richmond Creek (RC) watershed in the New York City Department of Environmental Protection's Bluebelt program, which incorporates BMP on a watershed basis. The BMP, designated RC-5, removed suspended solids (SS), but not chemical oxygen demand (COD). Calculated SS loads demonstrated a 61% removal in excess of anticipated removals of 55-57%. Of three events monitored for COD, one had no removal, the second negative 146%, and the third 37%. This increase in COD during the second event may be due to biological activity in RC-5, and seasonal considerations, i.e., decaying leaves and wetland vegetation going into dormancy. The largest SS and COD discharges occurred on 12/11/03, which was the largest rain (>1 in.) and flow event monitored. Results indicated that the number of storms monitored was adequate to describe SS removal using a paired t-test on composite influent and effluent data after applying log transformations. Directly calculating the significance using a statistical test randomly comparing two data sets, non-paired results (Burton and Pitt, 2002), indicated a 0.94 significance in the log transformed SS results at a power of 0.5, just shy of 95% confidence. The statistical analysis also implied that obtaining several more storm data might improve the statistical confidence with which the results could be stated.

Record Details: