Groundwater level trends and drivers in two northern New England glacial aquifers

Journal of the American Water Resources Association
By: , and 

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Abstract

We evaluated long-term trends and predictors of groundwater levels by month from two well-studied northern New England forested headwater glacial aquifers: Sleepers River, Vermont, 44 wells, 1992-2013; and Hubbard Brook, New Hampshire, 15 wells, 1979-2004. Based on Kendall Tau tests with Sen slope determination, a surprising number of well-month combinations had negative trends (decreasing water levels) over the respective periods. Sleepers River had slightly more positive than negative trends overall, but among the significant trends (p < 0.1), negative trends dominated 67 to 40. At Hubbard Brook, negative trends outnumbered positive trends by a nearly 2:1 margin and all seven of the significant trends were negative. The negative trends occurred despite generally increasing trends in monthly and annual precipitation. This counterintuitive pattern may be a result of increased precipitation intensity causing higher runoff at the expense of recharge, such that evapotranspiration demand draws down groundwater storage. We evaluated predictors of month-end water levels by multiple regression of 18 variables related to climate, streamflow, snowpack, and prior month water level. Monthly flow and prior month water level were the two strongest predictors for most months at both sites. The predictive power and ready availability of streamflow data can be exploited as a proxy to extend limited groundwater level records over longer time periods.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Groundwater level trends and drivers in two northern New England glacial aquifers
Series title Journal of the American Water Resources Association
DOI 10.1111/1752-1688.12432
Volume 52
Issue 5
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) New England Water Science Center
Description 19 p.
First page 1012
Last page 1030