Estimating Groundwater Discharge and Contaminant Loading to Newtown Creek, Brooklyn/Queens New York

Estimating the amount of groundwater discharging to a surface water body is a fundamental underpinning for establishing a comprehensive CSM. The Newtown Creek Superfund Site is a tidal estuary in an urban setting. Newtown Creek, a tributary to the East River and the New York Harbor Estuary, is 3.5 miles long and 200 feet wide, has five tributaries, and is surrounded by a prolific porous media aquifer. The creek has a complex hydrogeologic history and has been the recipient of historical and ongoing releases of contamination. Determining the groundwater discharge to the creek is the first step is assessing the importance of groundwater as a contaminant loading mechanism to the creek. Several methods were used to evaluate groundwater discharge to the creek including Thermal Imaging, Trident Probes, UltraSeeps seepage metering, and intrusive investigations using a barge-mounted Waterloo Profiler. Groundwater samples were collected and heads were measured at multiple depth within and below the sediment. This talk will discuss the methods used to collect the groundwater discharge and contaminant load information and the analyses that were undertaken to determine the importance of groundwater as sources of fresh water and contaminants to Newtown Creek. The analyses showed that groundwater is a significant source of contaminant loads, second only to loads contributed from NAPL migration.