Hydrology and numerical simulation of groundwater movement and heat transport in Snake Valley and surrounding areas, Juab, Miller, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod. To order this and other USGS information products, visit http://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AbstractSnake Valley and surrounding areas, along the UtahNevada state border, are part of the Great Basin carbonate and alluvial aquifer system. The groundwater system in the study area consists of water in unconsolidated deposits in basins and water in consolidated rock underlying the basins and in the adjacent mountain blocks. Most recharge occurs from precipitation on the mountain blocks and most discharge occurs from the lower altitude basin-fill deposits mainly as evapotranspiration, springflow, and well withdrawals.The Snake Valley area regional groundwater system was simulated using a three-dimensional model incorporating both groundwater flow and heat transport. The model was constructed with MODFLOW-2000, a version of the U.S. Geological Survey's groundwater flow model, and MT3DMS, a transport model that simulates advection, dispersion, and chemical reactions of solutes or heat in groundwater systems. Observations of groundwater discharge by evapotranspiration, springflow, mountain stream base flow, and well withdrawals; groundwater-level altitudes; and groundwater temperatures were used to calibrate the model. Parameter values estimated by regression analyses were reasonable and within the range of expected values.This study represents one of the first regional modeling efforts to include calibration to groundwater temperature data. The inclusion of temperature observations reduced parameter uncertainty, in some cases quite significantly, over using just water-level altitude and discharge observations. Of the 39 parameters used to simulate horizontal hydraulic conductivity, uncertainty on 11 of these parameters was reduced to one order of magnitude or less. Other significant reductions in parameter uncertainty occurred in parameters representing the vertical anisotropy ratio, drain and river conductance, recharge rates, and well withdrawal rates.The model provides a good representation of the groundwater system. Simulated water-level altitudes range over almost 2,000 meters (m); 98 percent of the simulated values of water-level altitudes in wells are within 30 m of observed water-level altitudes, and 58 percent of them are within 12 m. Nineteen of 20 simulated discharges are within 30 percent of observed discharge. Eighty-one percent of the simulate...

Beyond Classical Observations in Hydrogeology: The Advantages of Including Exchange Flux, Temperature, Tracer Concentration, Residence Time, and Soil Moisture Observations in Groundwater Model Calibration

“…This was found even though only 3 data points of Q GW were used alongside 13 data points of H, and despite the fact that the weighting scheme purely reflected the measurement uncertainty and was not scaled to guarantee equal importance to both observation groups. Also Masbruch et al (), in a study already discussed in section in relation to observations of T, showed with their data worth analysis that among all their observation types, the most informative for most of their model parameters was Q GW from spring discharge. Observations of ET and Q base , however, had negligible information content for their flow parameters if used alongside Q GW.…”

“…The benefits and the problems that are associated with these assumptions when evaluating model predictive uncertainty and data worth were discussed and compared to the nonlinear and more robust but computationally much more demanding Markov chain Monte Carlo method by Gallagher and Doherty (). Sensitivity analyses (see Hill & Tiedeman, ; Gannett et al, ; Masbruch et al, ; Rasa et al, ), influence statistics (see Hill & Tiedeman, ; La Vigna et al, ), and singular‐value‐decomposition‐based principal component analysis (see Doherty, ; Doherty & Hunt, ; Schilling et al, ) provide additional computationally efficient means to estimate the information content of specific observations or observation types. All these methods are based on the sensitivity matrices calculated with automated flow model calibration routines that are based on weighted multivariate objective functions.…”

“…Adding yet more observation types to model calibration and information content analysis, Masbruch et al () calibrated a 3‐D coupled flow, heat, and transport model of a real‐world system against observations of H, Q SW , T, and exchange fluxes (baseflow, spring discharge, and ET). Using the procedures implemented in UCODE, they employed a rigorous, multivariate‐objective‐function‐based calibration and systematically assessed the sensitivities between, and the information content of, the different unconventional observation types toward the calibrated parameters (quantifying composite scaled sensitivities, parameter correlations, influence statistics, and posterior confidence intervals).…”

“…The review showed that more often than not, the validity of flux or mass transport simulations calibrated against a combination of classical observations and T was not assessed by directly comparing the simulations to flux or mass transport observations. This is not good practice, especially in the light of the findings from the thorough analyses carried out by Bravo et al (), Kurtz et al (), Masbruch et al (), and Delsmann et al (), who demonstrated that as soon as there are multiple unknowns among the hydraulic and thermal properties and relevant exchange fluxes, and as soon as measurement errors are taken into account, calibration of an IFM against H and T is likely to result in correct temperature reproduction but incorrect representation of fluxes. If observations of T were complemented by a combination of classical and additional unconventional observations (e.g., by C or Q GW ), an acceptable calibration of flow, heat, and mass transport was much more likely.…”

Analyses of infrequent (quasi-decadal) large groundwater recharge events in the northern Great Basin: Their importance for groundwater availability, use, and management

“…The majority of groundwater recharge within the study area is assumed to occur in the higher‐altitude mountain range as direct infiltration of precipitation or snowmelt which, in part, is controlled by the bedrock permeability of the mountain blocks [ Masbruch et al ., ] or along mountain fronts. This assumption is supported by the analysis of environmental tracers and numerical modeling of groundwater flow in several studies within the Great Basin [ Brooks et al ., ; Masbruch et al ., ; Manning and Solomon , ]. Groundwater recharge also occurs through seepage from streams and canals, and from unconsumed irrigation of both surface water and groundwater.…”