Geophysics
Geophysics
The USGS uses an integrated geologic, hydrologic, and geophysical approach to characterize the unconsolidated and bedrock aquifers in the State. Hydrogeologic framework characterization is the backbone of most groundwater-related studies, including those involving aquifer mapping, saltwater-intrusion delineation, groundwater flow and transport modeling, geologic-hazards evaluation, water-tunnel construction and repair, geothermal assessments, and groundwater-quality sampling. The NYWSC uses state-of-the-art geophysical equipment for training and methods development for geophysics that include borehole-wall imagers, gamma spectral, induction, and full waveform sonic tools, and electromagnetic and heat-pulse flowmeters. A major recent study area is the Marcellus Shale of the Appalachian Basin, one of the largest formations that contain substantial accumulations of natural gas in the United States. Processing of the Marcellus Shale deposits, which were delineated on geophysical logs by their elevated gamma radiation and low density, require hydraulic fracturing; the NYWSC has been studying water resources issues associated with development of the Marcellus Shale deposits.
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Documenting Hydrogeologic Information Obtained from Deep-Borehole Drilling in Suffolk County, New York
Background Borehole drilling and well-installation are costly procedures, and securing funding for new well installation for the sake of research is often difficult.The Suffolk County Water Authority (SCWA) maintains a large network of deep wells for public supply that is constantly being upgraded as water demands increase. During the drilling process, contractors record drillers’ lo
Delineation of the Freshwater-Saltwater Interface at Selected Public-Supply Wells Using Advanced Surface and Borehole Geophysical Techniques, in Eastern Suffolk County, New York
The combination of a complex hydrogeologic framework, narrow land masses surrounded by saltwater, and extensive ground-water public-supply pumpage has produced localized areas of elevated chloride concentrations in ground water. This project uses advanced surface and borehole geophysical methods to determine the extent of saltwater intrusion and road-salt plumes at selected sites in eastern Suf
Delineation of Groundwater Flow, Lithology, Faults, and Fractures Along Existing and Proposed Water Tunnel
Problem The New York City Department of Environmental Protection (NYCDEP) has asked the U.S. Geological Survey (USGS) to assist in two major studies: 1) delineation of the source(s) of shallow groundwater and the extent that the Delaware Aqueduct is contributing to local flooding issues, and 2) delineation of the structural, geologic, and hydrologic conditions along proposed tunnel construction
Using Advanced Borehole Geophysical Methods to Characterize Fractures, Foliation, and Fractured-Rock Groundwater Flow at a Geothermal Test Site on Roosevelt Island, New York County, New York
Background The U.S. Geological Survey (USGS) has characterized fractures, foliation, and fractured-rock groundwater flow penetrated by test boreholes in crystalline bedrock underlying Manhattan Island, New York County, New York since 1998. New test boreholes will be drilled on Roosevelt Island in New York County for a Cornell University geothermal test project. Cornell University is partnering w
Aquifer Appraisal at the Tunison Laboratory of Aquatic Science, Cortland, New York
Problem - The Ithaca Subdistrict Office of the U.S. Geological Survey (USGS) is providing technical assistance to the USGS, Biological Resources Division (BRD), at the Tunison Laboratory of Aquatic Science (TLAS) in an investigation of the availability of fresh ground water. An expansion in the water supply at the laboratory is needed for a proposed spawning facility for salmon strains that are
Delineation of Rock Fractures, Faults, and Groundwater Flow in the Vicinity of Proposed Water Tunnels, New York City and Southeastern New York
Problem - The New York City Department of Environmental Protection (NYCDEP) is constructing or proposing water tunnels under New York City and areas of southeastern New York (Hudson River Basin). These tunnels can intersect faults and fractures that produce large amounts of ground water. For example, one tunnel excavation intersected fractures that produced over 200 gallons per minute of groun
Hydrogeology of the Tully Valley Mudboil Area, Southern Onondaga County, New York
Problem The Tully Valley, located in southern Onondaga County has been the source of sediment and brackish water discharge to Onondaga Creek, a tributary to the Seneca and Oswego Rivers and eventually Lake Ontario. Information on the origin of the Tully Valley mudboils, their persistence, and the possible extent of their migration within the Tully Valley is needed to mitigate or remediate (1)the d
Geohydrology of the Valley-Fill Aquifer in the Nanticoke Creek Valley near Endicott, New York
Problem The Village of Endicott relies on wells that supply ground water from sand and gravel aquifers within the Susquehanna River valley. Localized contamination in the Village of Endicott and elsewhere in the Susquehanna River Valley has been documented by U. S. Environmental Protection Agency (USEPA) and the New York State Department of Environmental Conservation (NYSDEC) from a number of comm
Hydrogeology and Surface/Groundwater Interactions in the Meads Creek Valley, Schuyler and Steuben Counties, New York
Problem - The interaction between ground water and surface water within the Meads Creek watershed is not well understood, and the need for understanding the interaction has increased in recent years because of widespread concerns related to water supply, ground- and surface-water contamination, loss of wetlands due to development; and other changes in the watershed. In addition, flooding in th
Nassau Hydrogeologic Maps
Problem - The major hydrogeologic units of Long Island, New York, have been delineated as part of the islandwide mapping effort of Smolensky, Buxton, and Shernoff that was published in 1989 as U.S. Geological Survey (USGS) Hydrologic Atlas (HA) 709. Concern about local details in the hydrogeologic framework that may not be represented in HA-709 has led the USGS, in cooperation with the U.S. Env