CHARACTERIZATION OF SURFACE AND GROUNDWATER CHEMISTRY BEFORE AND AFTER GAS DRILLING AND HYDRO-FRACTURING, TOWN OF MARYLAND, OTSEGO COUNTY, NEW YORK

Potentially, groundwater chemistry may be adversely affected by natural gas drilling and related activities such as hydro-fracturing; this study is an attempt to characterize water quality changes in response to such activities. Water analysis was conducted prior to, and subsequent to gas drilling and hydro-fracturing within a two-mile radius around the Ross well site in Central New York State, currently under active development. Drilling occurred in August 2009, followed by hydro-fracturing in November 2009. Within a two-mile radius of the Ross well, 18 residential wells and 12 surface waters were tested, including six residential wells and three surface waters down-flow (southeast) from the Ross well. Water samples were analyzed to determine concentrations of major elements, selected trace elements, and organic and volatile substances using ICP, ICP-MS, GC-MS, and Bacharach Cold Vapor Mercury Analyzer methods. Seasonal fluctuations in water chemistry and water table depth were not examined. The local unconfined aquifer water table is present within the upper part of the Hamilton Group; the approximate depth to the top of this aquifer was determined from perennial surface waters and well depths. The local aquifer occupies at least the Ludlowville and Skaneateles formations and is likely confined by the underlying Marcellus Shale. Gas-containing layers in the region include: the Marcellus Shale, a member of the Hamilton Group; the Oneida Conglomerate at the base of the Clinton Group; and the Utica Shale of the Trenton Group. Drilled depth of the Ross well is 4950 feet below ground level and extends into the Trenton Group, possibly as deep as the uppermost Precambrian basement The well casing extends 800 feet below the surface into the Skaneateles Formation, leaving approximately 415 feet of uncased well within the Skaneateles Formation. The uncased portion of the well continues through the remainder of the Hamilton Group, Onondaga Formation, Tristates, Helderberg, Clinton, Trenton, Chazy, Beekmantown Groups, and possibly into the Precambrian basement.