Factors related to well yield in the fractured-bedrock aquifer of New Hampshire

Abstract

The New Hampshire Bedrock Aquifer Assessment was designed to provide information that can be used by communities, industry, profes sional consultants, and other interests to evaluate the groundwater development potential of the fractured-bedrock aquifer in the State. The assess ment was done at statewide, regional, and well field scales to identify relations that potentially could increase the success in locating high-yield water supplies in the fractured-bedrock aquifer. statewide, data were collected for well construc tion and yield information, bedrock lithology, surficial geology, lineaments, topography, and various derivatives of these basic data sets. Regionally, geologic, fracture, and lineament data were collected for the Pinardville and Windham quadrangles in New Hampshire. The regional scale of the study examined the degree to which predictive well-yield relations, developed as part of the statewide reconnaissance investigation, could be improved by use of quadrangle-scale geologic mapping. Beginning in 1984, water-well contractors in the State were required to report detailed information on newly constructed wells to the New Hampshire Department of Environmental Services (NHDES). The reports contain basic data on well construction, including six character istics used in this study-well yield, well depth, well use, method of construction, date drilled, and depth to bedrock (or length of casing). The NHDES has determined accurate georeferenced locations for more than 20,000 wells reported

Discontinuous Nature of Phreatic Aquifers in Granitic Rocks at Watershed Scale: A Stratiform Model from Perennial Streams and Well Data

“…The advocated influence of lithology is consistent with the results of Moore, et al [27] orWalsh and Clark [28] under different climatic conditions but similar geology: migmatites display higher regolith thicknesses and yields than foliated plutons.…”

Identifying watershed-scale barriers to groundwater flow: Lineaments in the Canadian Shield

“…Previous studies document limited or inconsistent correlation between well yields and lineaments, suggesting that the permeability underlying lineaments is variable (Waters et al, 1990;Gustafsson, 1994;Mabee et al, 1994;Sander et al, 1997;Edet et al, 1998;Mabee, 1999;Magowe and Carr, 1999;Moore et al, 2002). Similarly, permeable zones with high infl ow in bedrock tunnels do not correlate consistently with the location of lineaments (Banks et al, 1992;Mabee et al, 2002).…”

“…Consulting hydrogeologists and researchers often continue to assume a priori that lineaments are fractured recharge and fl ow conduits with high groundwater potential (e.g., Krishnamurthy et al, 2000;Sener et al, 2005;Shaban et al, 2006). However, lineaments do not correlate with well yields, or only lineaments with certain characteristics correlate to well yields, but these correlations are not consistent across different geological, topographic, and geomorphic settings (Waters et al, 1990;Gustafsson, 1994;Mabee et al, 1994Mabee et al, , 2002Sander et al, 1997;Edet et al, 1998;Mabee, 1999;Magowe and Carr, 1999;Moore et al, 2002;Solomon and Quiel, 2006;Sander, 2007). Therefore, the assumption that lineaments are fractured conduits is not consistent with much of the well yield data around lineaments.…”

Methyl tert-Butyl Ether (MTBE) in Public and Private Wells in New Hampshire: Occurrence, Factors, and Possible Implications

“…Wells within 100 m of lineaments identified on 1:20000-scale photography had a 9-fold reduced odds of MTBE contamination (EXP( ) ) 0.113). Mapped lineaments are linear ground-surface features identified on aerial or satellite imagery that can indicate fractures in the underlying bedrock aquifers and are indicative in some areas of high-yielding water wells (16). One explanation is that MTBE may be diluted by high groundwater fluxes commonly associated with lineaments.…”