Temperature logging of groundwater in bedrock wells for geothermal gradient characterization in New Hampshire, 2012

Degnan, James; Barker, Gregory; Olson, Neil; Wilder, Leland

Abstract:

The U.S. Geological Survey, in cooperation with the New Hampshire Geological Survey, measured the fluid temperature of groundwater in deep bedrock wells in the State of New Hampshire in order to characterize geothermal gradients in bedrock. All wells selected for the study had low water yields, which correspond to low groundwater flow from fractures. This reduced the potential for flow-induced temperature changes that would mask the natural geothermal gradient in the bedrock. All the wells included in this study were privately owned, and permission to use the wells was obtained from homeowners before logging. Maximum groundwater temperatures at the bottom of the logs were between 11.7 and 17.3 degrees Celsius. Geothermal gradients were generally higher than typically reported for other water wells in the United States. Some of the high gradients were associated with high natural gamma emissions. Groundwater flow was discernible in 5 of the 10 wells studied but only obscured the portion of the geothermal gradient signal where groundwater actually flowed through the well. Temperature gradients varied by mapped bedrock type but can also vary by differences in mineralogy or rock type within the wells.

Genre:

USGS Numbered Series

ProdID:

70040577

Citation Author:

Degnan, James; Barker, Gregory; Olson, Neil; Wilder, Leland

Citation Contributing Office:

New England Water Science Center

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Citation Language:

English

Citation Larger Work Title:

Citation LatN:

45.310000

Citation LatS:

42.700000

Citation LonE:

-70.610000

Citation LonW:

-72.560000

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Citation Phsyical Description:

vi; 19 p.; Temperature and Gamma Geophysical Logs

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Citation Public Comments:

Prepared in cooperation with the New Hampshire Geological Survey

Citation Publisher:

U.S. Geological Survey

Citation Series:

Data Series

Citation Series Code:

Citation Series Number:

728

Citation Search Results Text:

Temperature logging of groundwater in bedrock wells for geothermal gradient characterization in New Hampshire, 2012; 2012; DS; 728; Degnan, James; Barker, Gregory; Olson, Neil; Wilder, Leland

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Citation Year:

2012

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citation/reference

Text:

Temperature logging of groundwater in bedrock wells for geothermal gradient characterization in New Hampshire, 2012; 2012; DS; 728; Degnan, James; Barker, Gregory; Olson, Neil; Wilder, Leland