Time-lapse gravity data for monitoring and modeling artificial recharge through a thick unsaturated zone

Water Resources Research
By: , and 

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Abstract

Groundwater-level measurements in monitoring wells or piezometers are the most common, and often the only, hydrologic measurements made at artificial recharge facilities. Measurements of gravity change over time provide an additional source of information about changes in groundwater storage, infiltration, and for model calibration. We demonstrate that for an artificial recharge facility with a deep groundwater table, gravity data are more sensitive to movement of water through the unsaturated zone than are groundwater levels. Groundwater levels have a delayed response to infiltration, change in a similar manner at many potential monitoring locations, and are heavily influenced by high-frequency noise induced by pumping; in contrast, gravity changes start immediately at the onset of infiltration and are sensitive to water in the unsaturated zone. Continuous gravity data can determine infiltration rate, and the estimate is only minimally affected by uncertainty in water-content change. Gravity data are also useful for constraining parameters in a coupled groundwater-unsaturated zone model (Modflow-NWT model with the Unsaturated Zone Flow (UZF) package).

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Time-lapse gravity data for monitoring and modeling artificial recharge through a thick unsaturated zone
Series title Water Resources Research
DOI 10.1002/2016WR018770
Volume 52
Issue 9
Year Published 2016
Language English
Publisher American Geophysical Union (Wiley)
Contributing office(s) Arizona Water Science Center
Description 18 p.
First page 7244
Last page 7261