MODFLOW6 models used to evaluate potential stresses and hydrologic conditions driving water-level fluctuations in well ER-5-3-2, Frenchman Flat, Southern Nevada

Dataset · Wed Mar 22 04:00:00 EDT 2023

DOI:https://doi.org/10.5066/P95C0NG5· OSTI ID:1962872

Jackson, Tracie R. ^[1]; Frus, Rebecca J. ^[2]

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1. USGS, Nevada Water Science Center; U.S. Geological Survey, Nevada Water Science Center, Boulder City, NV
2. USGS, Nevada Water Science Center

The hydrograph for well ER-5-3-2 in Frenchman Flat, southern Nevada, has previously unexplained water-level fluctuations. Four, three-dimensional, groundwater models (MODFLOW 6) were developed to evaluate potential stresses and hydrologic conditions affecting the well ER-5-3-2 hydrograph. Four model scenarios were developed that simulated: (1) wellbore leakage without recharge, (2) wellbore leakage with recharge, (3) shallow (low transmissivity) and deep (high transmissivity) carbonate rocks, and (4) lateral heterogeneity of carbonate rocks. Input and output files for the four model scenarios are in the model and output directories, respectively. Hydraulic conductivity, specific storage, and wellbore-leakage rates (when simulated) were estimated with parameter estimation (PEST) by minimizing a weighted composite, sum-of-squares objective function. The objective function was informed by measurement and Tikhonov regularization observations. Measurement observations included drawdowns from the constant-rate aquifer test and water-level altitudes measured in well ER-5-3-2 from 2001-2021. Tikhonov regularization informed hydraulic conductivity and specific storage parameters that were insensitive to measurement observations, where homogeneity was the preferred relation. Batch files, executables, and MODFLOW 6, PEST, and post-processing utilities are in the ancillary directory. Supplementary data also are included in the ancillary directory, including site information, high-frequency water-level and aquifer-test data, transmissivity estimates, water-chemistry data, and water-temperature analyses. This USGS data release contains data, analyses, and model files for the simulations and analysis results described in U.S. Geological Survey Scientific Investigations Report (https://doi.org/10.3133/sir20225132).

• Research Organization: U.S. Geological Survey, Nevada Water Science Center, Boulder City, NV
• Sponsoring Organization: USDOE; USDOE Office of Environmental Management (EM); USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: EM0004969
• OSTI ID: 1962872
• Report Number(s): 10.5066/P95C0NG5
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
ER-5-3-2
Frenchman Flat
Hydrograph
MODFLOW6
PEST
Tikhonov
USGS
aquifer-test
heterogeneity
homogeneity
model scenarios
water-chemistry
water-level
water-temperature