Evaluation of stream capture related to groundwater pumping, Lower Humboldt River Basin, Nevada

• DOI: 10.3133/sir20235110
• Publication Date: 2023-12-29T17:29:22Z
• Authors: Cara A. Nadler; Susan C. Rybarski; Hai Pham
• Keywords: MODFLOW; Groundwater model

First posted December 29, 2023 For additional information, contact: Director,Nevada Water Science CenterU.S. Geological Survey2730 N. Deer Run RoadCarson City, Nevada 89701 The Humboldt River Basin is the only river basin that contained entirely within State of Nevada. effect groundwater pumping on not well understood. Tools are needed to determine stream capture and manage in Basin. objective this study estimate storage change caused by withdrawals lower can provide Engineer with data information surface-water resources.A numerical flow model was developed for purpose estimating from pre-2016 future as any location potential This using MODFLOW-NWT represent hydrologic system, including River; Rye Patch Reservoir; evapotranspiration; municipal, agricultural, mining, domestic wells; agricultural drains. Aquifer properties were calibrated results numerous single- multi-well aquifer tests (Nadler, 2020) through process calibration.Historical estimated 1960–2016 predictive system projected 100 years into (2017–2116) based historical patterns. Stream drain relatively low periods. During period, increased during dry connections sources less water sourced wells storage. Storage levels generally recovered subsequent wet years. Overall, has been main source Basin, followed evapotranspiration capture. remain constant 9 percent after years.Capture maps created visualize spatial variability time a database be used resources. These show would minor located across most simulated area, except locations close Reservoir. Drains also those directly adjacent In general, supply storage-dominated over evapotranspiration-dominated area.Capture difference generated where might have greater limitations associated nonlinear processes, such head-dependent boundary conditions. Higher differences indicate larger map bias therefore uncertainty due inability account processes. highest but otherwise minimal. Drain region network River, Reservoir, drains introduce very little nonlinearity model, their Potential introduces fair amount result significant, localized time. Groundwater higher rates lowering table below root zone faster than essentially removing rates. Wells no longer then more Thus, increases well.Capture prediction parameter estimation evaluated covariance matrix adaptation-evolution strategy. One hundred Monte Carlo realizations parameters applied assess at 13 grid cell domain. indicated given (river, drains, or evapotranspiration) proximity source. magnitude maximum fraction uncertainties capture, plus minus (±) 0.17, ±0.10, ±0.20, ±0.22, respectively.