Multiple well-shutdown tests and site-scale flow simulation in fractured rocks

Groundwater
By: , and 

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Abstract

A new method was developed for conducting aquifer tests in fractured-rock flow systems that have a pump-and-treat (P&T) operation for containing and removing groundwater contaminants. The method involves temporary shutdown of individual pumps in wells of the P&T system. Conducting aquifer tests in this manner has several advantages, including (1) no additional contaminated water is withdrawn, and (2) hydraulic containment of contaminants remains largely intact because pumping continues at most wells. The well-shutdown test method was applied at the former Naval Air Warfare Center (NAWC), West Trenton, New Jersey, where a P&T operation is designed to contain and remove trichloroethene and its daughter products in the dipping fractured sedimentary rocks underlying the site. The detailed site-scale subsurface geologic stratigraphy, a three-dimensional MODFLOW model, and inverse methods in UCODE_2005 were used to analyze the shutdown tests. In the model, a deterministic method was used for representing the highly heterogeneous hydraulic conductivity distribution and simulations were conducted using an equivalent porous media method. This approach was very successful for simulating the shutdown tests, contrary to a common perception that flow in fractured rocks must be simulated using a stochastic or discrete fracture representation of heterogeneity. Use of inverse methods to simultaneously calibrate the model to the multiple shutdown tests was integral to the effectiveness of the approach.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Multiple well-shutdown tests and site-scale flow simulation in fractured rocks
Series title Groundwater
DOI 10.1111/j.1745-6584.2009.00651.x
Volume 48
Issue 3
Year Published 2010
Language English
Publisher Wiley
Contributing office(s) National Research Program - Western Branch, Toxic Substances Hydrology Program
Description 15 p.
First page 401
Last page 415
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