Pervasive, preferential flow through mega-thick unsaturated zones in the Southern Great Basin

Groundwater
By: , and 

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Abstract

Recharge from preferential flow through mega-thick (100–1,000 m) unsaturated zones is a pervasive phenomenon, as demonstrated with a case study of volcanic highland recharge areas in the Great Basin province in southern Nevada, USA. Statistically significant rising water-level trends occur for most study-area wells and resulted from a relatively wet period (1969–2005) in south-central Nevada. Wet and dry winters control water-level trends, with water levels rising within a few months to a year following a wet-winter recharge event and declining during sustained dry periods. Even though a megadrought has persisted since 2000, this drought condition did not preclude major recharge events. Modern groundwater reaching the water table is consistent with previous geochemical studies of the study area that indicate mixing of modern and late Pleistocene recharge water. First-order approximations and simple mixing models of modern and late Pleistocene water indicate that 10 to 40 percent of recharge is preferential flow and that modern recharge may play a larger role in the water budget than previously thought.

Publication type Article
Publication Subtype Journal Article
Title Pervasive, preferential flow through mega-thick unsaturated zones in the Southern Great Basin
Series title Groundwater
DOI 10.1111/gwat.13187
Volume 60
Issue 4
Year Published 2022
Language English
Publisher National Groundwater Association
Contributing office(s) Nevada Water Science Center
Description 14 p.
First page 496
Last page 509
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