SYNTHESIS OF GEOPHYSICAL AND HYDROGEOLOGIC DATA AT THE HYDE PARK LANDFILL

The Hyde Park Landfill, Niagara Falls, New York, sits atop the bedrock hydrogeologic system of the Niagara Falls escarpment, stretching from Watertown, New York to Manatoulin Island, Ontario. The landfill contains an estimated 73,000 tons of chemical waste, including chlorobenzoates and phenols. The Niagara watershed displays halogenated organic contamination due to chemical production and disposal at many sites in the region. The contaminants move as non-aqueous (DNAPL) and dissolved plumes through the bedrock. In the vicinity of the landfill, the shallow bedrock formations are primarily dolomite and limestone sequences. Hydrogeologic investigations at this site and others in the Niagara region have demonstrated that groundwater flow is controlled by the secondary porosity (bedding-plane fractures, vertical joints, and dissolution features). Regional studies have identified laterally extensive near-horizontal flow zones. However, previous site investigations have not been conducted at a vertical resolution sufficient to identify distinct flow zones. Detailed investigations are currently underway to collect additional geologic and hydrogeologic data to refine the conceptual geologic and hydrogeologic models of the Site. The tests are designed to identify individual flow zones, quantify the properties of these zones, and characterize the connectivity. The results of these tests will guide the implementation of additional remedial activities at the site. Ongoing investigations include geologic logging of new boreholes, borehole geophysics, borehole flowmeter, and hydraulic testing. A suite of geophysical testing is being conducted, including caliper, natural gamma, SP, resistivity, temperature, and sonic profiling. The program also includes logging with an acoustic televiewer and a borehole camera. This paper presents selected results from these investigations, with an emphasis on our attempts to synthesize the new data into a coherent impression of the bedrock properties. We discuss the relative utility of the individual geophysical tests at the site, and examine how the geophysical data relate to the results of hydrogeologic tests.