Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA

Hydrogeology Journal
By: , and 

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Abstract

Lysimeter-percolate and well-hydrograph analyses were combined to evaluate recharge for the Masser Recharge Site (central Pennsylvania, USA). In humid regions, aquifer recharge through an unconfined low-porosity fractured-rock aquifer can cause large magnitude water-table fluctuations over short time scales. The unsaturated hydraulic characteristics of the subsurface porous media control the magnitude and timing of these fluctuations. Data from multiple sets of lysimeters at the site show a highly seasonal pattern of percolate and exhibit variability due to both installation factors and hydraulic property heterogeneity. Individual event analysis of well hydrograph data reveals the primary influences on water-table response, namely rainfall depth, rainfall intensity, and initial water-table depth. Spatial and seasonal variability in well response is also evident. A new approach for calculating recharge from continuous water-table elevation records using a master recession curve (MRC) is demonstrated. The recharge estimated by the MRC approach when assuming a constant specific yield is seasonal to a lesser degree than the recharge estimate resulting from the lysimeter analysis. Partial reconciliation of the two recharge estimates is achieved by considering a conceptual model of flow processes in the highly-heterogeneous underlying fractured porous medium.

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Publication type Article
Publication Subtype Journal Article
Title Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA
Series title Hydrogeology Journal
DOI 10.1007/s10040-006-0149-6
Volume 15
Issue 5
Year Published 2007
Language English
Publisher Springer
Description 13 p.
First page 915
Last page 927
Country United States
State Pennsylvania
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