Diffuse-flow conceptualization and simulation of the Edwards aquifer, San Antonio region, Texas

Lindgren, R.J.

doi:10.3133/sir20065319

Cited by 21 publications

(81 citation statements)

References 11 publications

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“…a Initial values from Lindgren et al (2004), Lindgren (2006) and Musgrove et al (2010). b 95%-confidence, 95%-coverage tolerance limit based on log values except for pH, which is already a log value.…”

Section: Analytementioning

confidence: 99%

Section: Unconfined Carbonate Aquifermentioning

confidence: 99%

“…Aquifer heterogeneity in the Edwards is controlled by large and unpredictable variations in karst features (Lindgren, 2006). We assumed random Gaussian variations in permeability, using mean, variance, and correlation lengths determined for this aquifer by Painter et al (2007) and Lindgren (2006) (Table 3). Stochastic fields of heterogeneous permeability were generated using the pilot point method and random Gaussian interpolation (Deutsch and Journel, 1992;Dai et al, 2007;Harp et al, 2008).…”

Section: Unconfined Carbonate Aquifermentioning

confidence: 99%

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Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

Carroll

Keating

Mansoor

et al. 2014

International Journal of Greenhouse Gas Control

113

106

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a b s t r a c tIn this paper we describe potential impacts to groundwater quality due to CO 2 and brine leakage, discuss an approach to calculate thresholds under which "no impact" to groundwater occurs, describe the time scale for impact on groundwater, and discuss the probability of detecting a groundwater plume should leakage occur. To facilitate this, multi-phase flow and reactive transport simulations and reduced-order models were developed for two classes of aquifers, considering uncertainty in leakage source terms and aquifer hydrogeology. We targeted an unconfined fractured carbonate aquifer based on the Edwards Aquifer in Texas and a confined alluvium aquifer based on the High Plains Aquifer in Kansas, which share characteristics typical of many drinking water aquifers in the United States. The hypothetical leakage scenarios centered on the notion that wellbores are the most likely conduits for brine and CO 2 leaks. Leakage uncertainty was based on hypothetical injection of CO 2 for 50 years at a rate of 5 million tons per year into a depleted oil/gas reservoir with high permeability and, one or more wells provided leakage pathways from the storage reservoir to the overlying aquifer. This scenario corresponds to a storage site with historical oil/gas production and some poorly completed legacy wells that went undetected through site evaluation, operations, and post-closure.For the aquifer systems and leakage scenarios studied here, CO 2 and brine leakage are likely to drive pH below and increase total dissolved solids (TDS) above the "no-impact thresholds"; and the subsequent plumes, although small, are likely to persist for long periods of time in the absence of remediation. In these scenarios, however, risk to human health may not be significant for two reasons. First, our simulated plume volumes are much smaller than the average inter-well spacing (1-2.6 wells/km 2 ) for these representative aquifers, so the impacted groundwater would be unlikely to be pumped for drinking water. Second, even within the impacted plume volumes little water exceeds the primary maximum contamination levels. These observations point to: BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). 154 S.A. Carroll et al. / International Journal of Greenhouse Gas Control 29 (2014) 153-168• The potential utility of uncertainty quantification methods to evaluate the risk of leakage and inform monitoring and corrective action plans of a potential site for long-term CO 2 storage by capturing storage reservoir, leakage pathway, and aquifer heterogeneity. • The importance of establishing baseline groundwater chemistry that captures the pre-injection variability of underground sources of drinking water (USDW) above the reservoir because the EPA has adopted a "no net degradation" policy toward the protection of groundwater resources. • The need to test and develop spatially diverse monitoring techniques capable of detecting leakage early to employ effective mitigation strategies, and more importantly to add confidence to as...

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Section: Analytementioning

confidence: 99%

Section: Unconfined Carbonate Aquifermentioning

confidence: 99%

Section: Unconfined Carbonate Aquifermentioning

confidence: 99%

See 1 more Smart Citation

Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

Carroll

Keating

Mansoor

et al. 2014

International Journal of Greenhouse Gas Control

113

106

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show abstract

“…The accuracy of computer simulations (Maclay and Land 1988;Kuniansky and Holligan, 1994;Lindgren and others, 2004;Lindgren, 2006) of the Edwards aquifer can be improved by incorporating more detailed information pertaining to the geology and geologic structure controlling groundwater flow paths of the system. This is particularly true for a part of the Edwards aquifer locally known as the Knippa Gap in the western part of the Edwards aquifer near Knippa, Tex.…”

Section: Introductionmentioning

confidence: 99%

Geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Texas

Clark¹,

Pedraza²,

Morris³

2013

Scientific Investigations Report

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“…SEAWAT allows for more accurate simulation of effects of increased dissolved-solids concentrations (such as those seen in the brackish-water transition zone and saline zone) on density and groundwater flow. Using SEAWAT for this model analysis required the Edwards aquifer to be simulated with eight model layers, many more than were used in previous numerical models of the aquifer (Lindgren and others, 2004;Lindgren, 2006). This increased vertical discretization allows for better representation of the hydrostratigraphy of the aquifer ( fig.…”

Section: What Was the Focus Of The Model?mentioning

confidence: 99%

New insights into the Edwards Aquifer—Brackish-water simulation, drought, and the role of uncertainty analysis

Foster¹,

White²

2016

Fact Sheet

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• Uncertainty analysis provided insights as to the reliability of the model inputs and model results.• Brackish water is not expected to move appreciably toward production wells near the transition zone interface if a repeat of drought-of-record conditions occurs.• The model is reliable for predicting brackish-water movement near production wells.• The model is not reliable for predicting Bexar County index well J-17 water levels or for predicting flows at Comal and San Marcos Springs.• Many hydraulic properties of the Edwards aquifer, as well as recharge to the aquifer, remain highly uncertain, even after the model has been calibrated.

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Diffuse-flow conceptualization and simulation of the Edwards aquifer, San Antonio region, Texas

Cited by 21 publications

References 11 publications

Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

Geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Texas

New insights into the Edwards Aquifer—Brackish-water simulation, drought, and the role of uncertainty analysis

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