Development and Application of Numerical Models to Estimate Fluxes through the Regional Aquifer beneath the Pajarito Plateau

Keating, E. H.; Robinson, Bruce A.; Vesselinov, Velimir V.

doi:10.2136/vzj2004.0101

Cited by 16 publications

(14 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Definition of hydrogeological units is an iterative process, and further refinement of hydrogeological units is expected as additional hydrological measurements for rock units become available. Keating et al (2005) discussed the development and application of numerical models for estimating fluxes through the groundwater system beneath the Pajarito Plateau.…”

Section: Relation Between Geologic and Hydrogeologic Frameworkmentioning

confidence: 99%

“…Potentiometric maps indicate that the Sierra de los Valles is an important recharge area for the Pajarito Plateau groundwater system (Purtymun, 1984; Rogers et al, 1996; Keating et al, 2005). Regional groundwater moves generally eastward across the plateau toward the Rio Grande (Purtymun and Johansen, 1974; Purtymun, 1984, 1995).…”

Section: Geologic Setting Of Groundwater Occurrencesmentioning

confidence: 99%

“…Regional groundwater moves generally eastward across the plateau toward the Rio Grande (Purtymun and Johansen, 1974; Purtymun, 1984, 1995). Keating et al (2005) discussed potentiometric maps, hydraulic gradients, and permeability data for the regional saturated zone.…”

Section: Geologic Setting Of Groundwater Occurrencesmentioning

confidence: 99%

See 2 more Smart Citations

Geologic Framework of a Groundwater System on the Margin of a Rift Basin, Pajarito Plateau, North‐Central New Mexico

Broxton

Vaniman

2005

Vadose Zone Journal

View full text Add to dashboard Cite

that includes the LANL and the adjacent communities of Los Alamos and White Rock, San Ildefonso Pueblo The Pajarito Plateau is an important source of abundant potable land west of the Rio Grande, and a northern outlying groundwater for Los Alamos National Laboratory (LANL) and the part of Bandelier National Monument (Fig. 3). Areas communities of Los Alamos and White Rock. Geologic investigations were undertaken as part of a plateau-wide hydrogeological investiga-of the southern Pajarito Plateau in Bandelier National tion to develop conceptual models of the groundwater system as a Monument are not discussed because there are no hyframework for numerical simulations of groundwater flow. The Pajadrogeologic data from wells in this area. The northern rito Plateau is located in the western part of the Españ ola basin where plateau is not discussed because hydrogeologic data for rocks of the Jemez and Cerros del Rio volcanic fields overlie and the Santa Clara Pueblo is not available to the public. interfinger with Neogene basin-fill sedimentary rocks. The vadose Groundwater drawn from beneath the plateau is the zone is about 200 m (600 ft) thick beneath mesas on the east side of primary source of municipal and industrial water used the plateau and more than 375 m (1245 ft) thick on the west side. by LANL and by adjacent communities. Water supply Groundwater occurs as shallow groundwater in canyon-floor alluvium, wells on the plateau are 600 to 950 m (2000-3110 ft) moderately deep groundwater perched in bedrock units of the vadose zone, and groundwater associated with the regional saturated zone.deep (Purtymun, 1995;Koch and Rogers, 2003), andThe most productive rocks of the regional aquifer occur in a westward-they tap the western-central part of the Españ ola basin thickening wedge of coarse-grained, Miocene and Pliocene volcaregional aquifer in Miocene and Pliocene sedimentary niclastic rocks derived from the Jemez volcanic field. Eastern aquifer and volcanic rocks. Although numerous wells penetrate rocks consist of fine-grained, somewhat less productive Miocene sedithe upper part of the regional saturated zone, none fully mentary deposits derived from highland sources to the east and north.penetrate the aquifer. Intermediate and mafic lavas interbedded with the Miocene and Plio-Water quality is typically good, but the effects of cene sedimentary deposits are components of the regional aquifer LANL operations can be detected in parts of the locally. The hydrogeology of the Pajarito Plateau is probably typical groundwater system. Locally, shallow and intermediate of groundwater systems along the margins of the Rio Grande rift where arid to semiarid, sediment-filled basins receive most of their perched groundwater systems of the vadose zone conrecharge from adjacent mountainous areas.

show abstract

Section: Relation Between Geologic and Hydrogeologic Frameworkmentioning

confidence: 99%

Section: Geologic Setting Of Groundwater Occurrencesmentioning

confidence: 99%

See 1 more Smart Citation

Geologic Framework of a Groundwater System on the Margin of a Rift Basin, Pajarito Plateau, North‐Central New Mexico

Broxton

Vaniman

2005

Vadose Zone Journal

View full text Add to dashboard Cite

show abstract

“…The focus of this paper is the deep perched groundwater. A brief description of the alluvial groundwater is presented below for completeness, and the regional aquifer is described elsewhere (Keating et al, 2005).…”

Section: Perched Water Observations Beneath the Pajarito Plateaumentioning

confidence: 99%

Observations and Modeling of Deep Perched Water Beneath the Pajarito Plateau

Robinson

Broxton

Vaniman

2005

Vadose Zone Journal

Self Cite

View full text Add to dashboard Cite

est because (i) they represent natural groundwater resources that are protected under State law; (ii) their Geologic characterization of the Pajarito Plateau, in support of chemical and isotopic characteristics help constrain environmental investigations of potential groundwater contamination at Los Alamos National Laboratory, has provided the opportunity to groundwater transport rates through the vadose zone; examine the nature and extent of deep perched groundwater in this (iii) perching horizons may divert, slow, or stop the semiarid setting. Deep perched groundwater occurs at widely dispersed vertical migration of groundwater through the vadose locations across the Pajarito Plateau. A total of 33 perched-zone occurzone, or they may indicate the presence of a fast subrences were identified in 29 wells. The saturated thickness of perched surface pathway, depending on the characteristics of the zones is highly variable, ranging from about 1 to Ͼ122 m (Ͼ400 ft).perched zone; and (iv) they can be used as vadose zone Observations are consistent with a conceptual model of low-permemonitoring points that provide early warning of conability horizons on which infiltrating water sits. Deep perched groundtaminants approaching the regional aquifer. water is most often found beneath wet canyons, suggesting that in The vadose zone beneath the Pajarito Plateau ranges addition to perching horizons, locally high percolation rates are rein thickness from 180 m (590 ft) to more than 365 m quired to yield saturated conditions. Two conceptual models of perching systems are considered, one relatively stagnant and one more dy-(1200 ft), and it consists of Pliocene alluvial fan deposits namic. To simulate deep perched groundwater in vadose zone flow covered by thick Pleistocene ash-flow tuffs. The Pliomodels, a new method is developed that considers the interfaces becene sediments interfinger laterally with lavas from the tween hydrogeologic units to be the horizons where the saturated Jemez volcanic field to the west and the Cerros del Rio permeability is lower than either of the units above or below the intervolcanic field to the east. An in-depth description of face. A constant multiplier called the permeability reduction factor is the geology of the Pajarito Plateau is presented by Broxapplied at the interface between two hydrostratigraphic units to simuton and Vaniman (2005), who explain and illustrate the late the perching horizon. We demonstrate the method with two-dimenstratigraphic units discussed here. Perched groundwater sional numerical simulations performed for Los Alamos Canyon, repliis found within canyon-bottom alluvium and within bedcating perched saturation as observed and showing how contaminant rock units of the vadose zone. Characterization of these dispersal may be enhanced in certain perched systems compared with dispersion in the underlying zone of regional saturation.

show abstract

“…Physically based, watershed‐scale models that include the unsaturated zone (Corwin 1996; Vanclooster et al 2005) that are both robust and efficient can improve our understanding of both human impacts (Keating et al 2005; Schoups et al 2005; Panday et al 2009) and climate variability (Earman and Dettinger 2011) on the quality of groundwater resources since unsaturated zone transport effects the fate of contaminants as they are transmitted between land surface and the water table (Nielsen et al 1986) as well as to streams (Kirchner et al 2000). This new functionality will stand to benefit the large number of MODFLOW and MT3DMS users (Panday and Huyakorn 2008; Hill et al 2010) by providing the capabilities necessary for extending existing regional‐scale MODFLOW‐MT3DMS models to the unsaturated zone.…”

Section: Introductionmentioning

confidence: 99%

Modeling Variably Saturated Subsurface Solute Transport with MODFLOW‐UZF and MT3DMS

et al. 2012

View full text Add to dashboard Cite

The MT3DMS groundwater solute transport model was modified to simulate solute transport in the unsaturated zone by incorporating the unsaturated‐zone flow (UZF1) package developed for MODFLOW. The modified MT3DMS code uses a volume‐averaged approach in which Lagrangian‐based UZF1 fluid fluxes and storage changes are mapped onto a fixed grid. Referred to as UZF‐MT3DMS, the linked model was tested against published benchmarks solved analytically as well as against other published codes, most frequently the U.S. Geological Survey's Variably‐Saturated Two‐Dimensional Flow and Transport Model. Results from a suite of test cases demonstrate that the modified code accurately simulates solute advection, dispersion, and reaction in the unsaturated zone. Two‐ and three‐dimensional simulations also were investigated to ensure unsaturated‐saturated zone interaction was simulated correctly. Because the UZF1 solution is analytical, large‐scale flow and transport investigations can be performed free from the computational and data burdens required by numerical solutions to Richards' equation. Results demonstrate that significant simulation runtime savings can be achieved with UZF‐MT3DMS, an important development when hundreds or thousands of model runs are required during parameter estimation and uncertainty analysis. Three‐dimensional variably saturated flow and transport simulations revealed UZF‐MT3DMS to have runtimes that are less than one tenth of the time required by models that rely on Richards' equation. Given its accuracy and efficiency, and the wide‐spread use of both MODFLOW and MT3DMS, the added capability of unsaturated‐zone transport in this familiar modeling framework stands to benefit a broad user‐ship.

show abstract

Development and Application of Numerical Models to Estimate Fluxes through the Regional Aquifer beneath the Pajarito Plateau

Cited by 16 publications

References 26 publications

Geologic Framework of a Groundwater System on the Margin of a Rift Basin, Pajarito Plateau, North‐Central New Mexico

Geologic Framework of a Groundwater System on the Margin of a Rift Basin, Pajarito Plateau, North‐Central New Mexico

Observations and Modeling of Deep Perched Water Beneath the Pajarito Plateau

Modeling Variably Saturated Subsurface Solute Transport with MODFLOW‐UZF and MT3DMS

Contact Info

Product

Resources

About