Premium
Pervasive, Preferential Flow through Mega‐Thick Unsaturated Zones in the Southern Great Basin
Author(s) -
Jackson Tracie R.,
Fenelon Joseph M.,
Gainey Seth R.
Publication year - 2022
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/gwat.13187
Subject(s) - groundwater recharge , water table , structural basin , geology , hydrology (agriculture) , volcano , depression focused recharge , period (music) , groundwater , geochemistry , paleontology , aquifer , physics , geotechnical engineering , acoustics
Abstract Recharge from preferential flow through mega‐thick (100–1000 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% of recharge is preferential flow and that modern recharge may play a larger role in the water budget than previously thought.