Tracking tracer breakthrough in the hyporheic zone using time‐lapse DC resistivity, Crabby Creek, Pennsylvania

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Abstract

Characterization of the hyporheic zone is of critical importance for understanding stream ecology, contaminant transport, and groundwater‐surface water interaction. A salt water tracer test was used to probe the hyporheic zone of a recently re‐engineered portion of Crabby Creek, a stream located near Philadelphia, PA. The tracer solution was tracked through a 13.5 meter segment of the stream using both a network of 25 wells sampled every 5–15 minutes and time‐lapse electrical resistivity tomographs collected every 11 minutes for six hours, with additional tomographs collected every 100 minutes for an additional 16 hours. The comparison of tracer monitoring methods is of keen interest because tracer tests are one of the few techniques available for characterizing this dynamic zone, and logistically it is far easier to collect resistivity tomographs than to install and monitor a dense network of wells. Our results show that resistivity monitoring captured the essential shape of the breakthrough curve and may indicate portions of the stream where the tracer lingered in the hyporheic zone. Time‐lapse resistivity measurements, however, represent time averages over the period required to collect a tomographic data set, and spatial averages over a volume larger than captured by a well sample. Smoothing by the resistivity data inversion algorithm further blurs the resulting tomograph; consequently resistivity monitoring underestimates the degree of fine‐scale heterogeneity in the hyporheic zone.

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Additional publication details

Publication type Conference Paper
Title Tracking tracer breakthrough in the hyporheic zone using time‐lapse DC resistivity, Crabby Creek, Pennsylvania
DOI 10.4133/1.3445534
Year Published 2010
Language English
Publisher Environmental and Engineering Geophysical Society
Contributing office(s) Branch of Regional Research-Central Region
Larger Work Type Conference Paper
Larger Work Title Proceedings of the 23rd Annual Symposium on the Application of Gephysics to Engrineering and Envrionmental Problems (SAGEEP) Keystone, CO April 11-15, 2010
Conference Title 23rd Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP)
Conference Location Keystone, CO
Conference Date April 11-15 2010
Country United States
State Pennsylvania
Other Geospatial Crabby creek
Online Only (Y/N) N
Additional Online Files (Y/N) N