Five Gallons in a Ten Gallon Hat: Groundwater Sustainability in Texas

Despite the hopes and desires of scientists, engineers, and planners, the projected future of groundwater production in Texas is unsustainable. About 95 percent of locally-expressed desired future conditions are based on water-level declines, groundwater is currently being produced at 1.8 times the maximum sustainable amount, and groundwater is expected to be produced 2.4 times the maximum sustainable amount. However, Texas has an opportunity to consider groundwater sustainability since current production for all aquifers excluding the Ogallala Aquifer is only 80 percent of the maximum sustainable amount of production.To better understand how groundwater is produced sustainably, I identified five types of sustainable groundwater management in Texas: (1) hydrologically-forced, (2) court-forced, (3) legislatively-forced, (4) desire-driven, and (5) de facto. There is also the situation where it is politically difficult to achieve sustainability, generally when production far exceeds sustainable production, thus requiring controversial production reductions. Hydrologically-forced sustainable production seems to only occur when aquifers are small and highly productive. In Texas, part of the Edwards and Gulf Coast aquifers are sustainably managed due to court and legislative forcing, the latter in response to the former. Through the establishment of desired future conditions, a dozen or so groundwater conservation districts have explicitly expressed a desire to manage groundwater resources sustainably. And there are cases of aquifers being produced sustainably without any management action--at least for now. But there are also many aquifers not produced sustainably because production or permits have exceeded maximum sustainable production.Based on the results of this study, I recommend that (1) groundwater conservation districts include decadal water budgets in explanatory reports for desired future conditions or the Texas Water Development Board include these budgets as part of the delivery of modeled available groundwater numbers, (2) the Texas Water Development Board carefully consider the process of estimating maximum sustainable production if and when they are required to provide those estimates, and (3) the Legislature consider requiring maximum sustainable production as another factor for groundwater conservation districts to consider when establishing desired future conditions

Solute Transport through the Austin Chalk Weathered Zone at the SSC Site

The purpose of this work is to better understand the occurrence and movement of groundwater and the transport of solutes in near-surface Austin Chalk in the vicinity of the Superconducting Super Collider (SSC) site. The scope of work includes (1) further characterization of the hydrogeological attributes of the weathered zone pertinent to solute transport and (2) numerical simulation of groundwater flow and solute transport to estimate solute transport time and paths. This work determines transport times and relative solute concentrations in the vicinity of spoil piles, the linear accelerator, or other potential sources of contamination at the SSC site. The results summarized in this report will be useful for assessing the risk of solute migration from the SSC site and evaluating short- and long-term monitoring needs. This report presents the results of (1) further characterization of the weathered zone, (2) interpretive models generalized for average weathered-zone properties and environment, and (3) three-dimensional modeling of groundwater flow and solute transport at the West Campus of the SSC. Characterization and modeling work focus on the hydrologic and geographic setting of the West Campus, which can be used as an analog for flow and transport beneath spoil piles located at the access sites at various locations on the SSC footprint underlain by Austin Chalk.Bureau of Economic Geolog

Internet of Texas Water Data: Use Cases for Flood, Drought, and Surface Water –Groundwater Interaction

Texas’ public and private companies, organizations, and agencies have collected water data for different purposes and at different scales for many years. These data are scattered across multiple platforms with different standards, often making important data sets inaccessible or incompatible. This leaves Texas’ decision makers, industries, landowners, and communities with significant amounts of data of limited use to support real-time decision making, development of opportunities for water security, or for modeling an accurate picture of Texas’ water future. On April 17, 2018, the Connecting Texas Water Data Workshop brought together experts representative of Texas’ water sectors to engage in the identification of critical water data needs and discuss the design of a data system that facilitates access to and use of public water data in Texas. Workshop participants described desires for future water data management and access, and key attributes of a comprehensive, open access, public water data information system.https://digitalcommons.tamusa.edu/water_books/1000/thumbnail.jp

Hydrologic and Hydrogeologic Survey of Camps Barkley, Bowie, Mabry, Maxey, and Swift and Fort Wolters

The Bureau of Economic Geology (BEG) is conducting hydrologic and hydrogeologic studies of Texas National Guard training facilities at Camps Barkley, Bowie, Mabry, Maxey, and Swift and Fort Wolters. These investigations, in conjunction with aquatic and biological surveys conducted by the Texas Parks and Wildlife Department, will provide information needed by the Texas National Guard to plan training and preparedness activities such that environmental resources will be protected and enhanced without compromising national security readiness. This report presents data and analyses collected and performed by BEG researchers from October through December 1995. The activities presented in this report include results of the (1) hydrogeologic analysis, (2) surface-water analysis, and (3) well inventory on the camps and fort. The hydrogeologic analysis includes hydrostratigraphy, aquifer properties, ground-water chemistry, water levels, preliminary conceptual flow model, and drilling plans. Surface-water analysis includes description of principal streams and drainage basins, watershed delineation, and plots of flow duration and frequency. We present some results of our drilling program in the hydrogeologic analysis. Well reports will be presented in our February interim report and well tests and analyses in the final report. This report is divided into 6 sections with each section discussing the hydrologic and hydrogeologic assessment for an individual training facility.Bureau of Economic Geolog

Floodplain Analyses and Drilling Reports for Camps Barkeley, Bowie, Mabry, Maxey, and Swift and Fort Wolters

The Bureau of Economic Geology (BEG) is conducting hydrologic and hydrogeologic studies of Texas National Guard training facilities at Camps Barkeley, Bowie, Mabry, Maxey, and Swift and Fort Wolters. These investigations, in conjunction with aquatic and biological surveys conducted by the Texas Parks and Wildlife Department, will provide information needed by the Texas National Guard to plan training and preparedness activities such that environmental resources will be protected and enhanced without compromising national security readiness. This report presents interim results on floodplain analysis and drilling activities. Floodplain analysis results include 100-year rainfalls, 100-year flood hydrographs at camp and fort outlets, and maps of the 100-year floodplain at each training facility. Our drilling results include well schematics, well schedules, and location maps. Results are reported in 6 sections with each section discussing the drilling reports and floodplain mapping for an individual training facility. The methods section contains details about the procedures used to drill and complete the wells and map the floodplains.Bureau of Economic Geolog

Assigning Water Levels and Ground Water Depletions in the Ogallala Aquifer

The purpose of this report is to evaluate the assignment of water levels in monitor wells in order to create ground-water depletion maps of the Panhandle Ground Water Conservation District No. 3 (PGWCD No. 3). Ground-water depletion maps document and quantify the decrease in ground-water resources in the PGWCD No. 3 by monitoring the historical lowstand of water levels in the Ogallala aquifer. They are used to assign water-level declines to eligible properties for Federal tax credit. Because area landowners rely on these maps for such assignments and because the maps are used in documenting ground-water resources, the procedures used in their creation should be accurate, fair, and timely. The PGWCD No. 3 currently uses a floating, 5-yr, back- calculated average to guide water-level assignments used in generating ground-water-depletion maps. This approach, however, may significantly underestimate water-level declines in individual wells and may give nonreproducible results from well to well. During this study, we assessed the limitations of this approach, described the complications of assigning water levels, and evaluated alternative approaches to define water levels used in determining depletions more accurately. Our goal was to develop a defensible approach that more accurately represents water levels in the Ogallala aquifer. This report specifies how water levels should be assigned in monitor wells in order to minimize errors and provide the most hydrologically reasonable, defensible, and accurate water- level declines. A subsequent report will discuss an automated and statistically rigorous method for assigning depletions to individual properties. These reports will allow the PGWCD No. 3 to maximize the quality of the data used in depletion analysis and to minimize the errors and time used in assigning depletions in the district.Bureau of Economic Geolog

Lubbock County Pilot Study for Development of a Hydrogeologic Geographic Information System (HGIS) to Support TNRCC Implemation of Risk Reduction Rules

Regional hydrologic, geologic, soils, and cultural background information and data from 217 leaking petroleum storage tank (LPST) sites in Lubbock County, Texas, are used to construct an Arc/INFO Geographic Information System (GIS). The study evaluates the use of this technology to provide context information for new site evaluation and risk assessment as well as to evaluate the effectiveness of past site characterization, risk assessment, and remediation strategies. Methods and costs of producing the database in this pilot study are described. Several analyses of these data are presented as a demonstration of the uses of this tool. The heterogeneity within the unsaturated zone is characterized spatially and statistically. Hydrologic variables including water level and hydraulic conductivity from well tests are mapped. The effect of this observed variability on Risk-Based Corrective Action (RBCA) calculations is assessed. The evolution of contaminant plumes can be viewed, and relationships between plumes and water-supply wells quantified. This pilot study demonstrates an application of GIS technology to a moderate-size dataset of contaminated-site information. The demonstration is intended not only to provide information about the Lubbock County study area but also to serve as a prototype and feasibility study for the application of this technology to other large contaminated-site datasets, including LPST-site data in other major urban areas, other types of contaminated sites, and industry applications.Bureau of Economic Geolog

Ground-Water and Surface-Water Hydrology of Camp Bowie, Brown County, Texas

Data for this report is available at the Texas Data Repository: https://doi.org/10.18738/T8/UMVGJPGround-water and surface-water investigations of Camp Bowie, Brown County, Texas, were conducted to provide the Texas Army National Guard information needed to preserve environmental quality and resources while planning and conducting training and preparedness activities. Spatial information such as surface geology, watersheds, elevation data, floodplains, well locations, and water levels were converted to digital files and submitted to the Texas Army National Guard Geographic Information System office at Camp Mabry, Austin, Texas, for future use in managing the training facility. Similar investigations were conducted at Camps Barkeley, Mabry, Maxey, and Swift, and at Fort Wolters. Results of those studies are presented separately. Previously published reports and public data files were examined to obtain background information on the camp and surrounding area. These data were used to guide more focused studies on the training facility. Ground-water studies included locating existing wells on and near the camp, installing new wells as needed, testing and sampling selected wells, determining ground-water levels, chemical compositions, and aquifer hydraulic properties, and developing a conceptual model of ground-water flow. Surface-water studies focused on delineating watersheds and mapping floodplains.Bureau of Economic Geolog

Ground-Water and Surface-Water Hydrology of Camp Mabry, Travis County, Texas

Ground-water and surface-water hydrologic investigations of Camp Mabry, Travis County, Texas, were conducted to provide the Texas Army National Guard information needed to plan and conduct training and preparedness activities while preserving environmental quality and resources. Spatial information such as surface geology, watersheds, elevation data, floodplains, well locations, and water levels were converted to digital files and submitted to the Texas Army National Guard Geographic Information System office at Camp Mabry, Austin, Texas, for future use in managing the training facility. Similar investigations were conducted at Camps Barkeley, Bowie, Maxey, and Swift and at Fort Wolters. Results of those studies are presented separately. Previously published reports and public data files were examined to obtain background information on the camp and surrounding area. These data were used to guide more focused studies on the training facility. Ground-water studies included locating existing wells in and near the camp, installing new wells as needed, testing and sampling selected wells, determining ground-water levels, chemical compositions, and aquifer hydraulic properties, and developing a conceptual model of ground-water flow. Surface-water studies focused on delineating watersheds and mapping floodplains.Bureau of Economic Geolog

Predictions of Groundwater Levels and Spring Flow in Response to Future Pumpage and Potential Future Droughts in the Barton Springs Segment of the Edwards Aquifer

A two-dimensional numerical groundwater-flow model was developed for the Barton Springs segment of the Edwards aquifer to evaluate groundwater availability and predict water levels and spring flow in response to increased pumpage and droughts from 2000 through 2050. A steady-state model was developed on the basis of average recharge for a 20-yr period (1979 through 1998) and pumpage values for 1989. Hydraulic conductivity zones (10) were adjusted to obtain good agreement between measured and simulated hydraulic heads. Zones of hydraulic conductivity ranged from 1 to 1,000 ft/d. We conducted transient simulations using recharge and pumping data for a 10-yr period from 1989 through 1998 that includes periods of low and high water levels. Good agreement was found between measured and simulated flow at Barton Springs (root mean square error [RMSE, average of squared differences in measured and simulated discharges] 17 cfs) and between measured and simulated water levels in many of the monitoring wells (mean RMSE 40 ft). The simulation results overestimate spring discharge by about 10 cfs during low flow periods. To assess the impact of future pumping and potential future droughts on groundwater availability, we conducted transient simulations using extrapolated pumpage for a 10-yr period (2041 through 2050) and using average recharge for a 3-yr period and recharge from the 1950s drought for the remaining 7 yr. Results for this scenario predict that flow in Barton Springs will become very low ( 4 cfs) toward the end of the drought. Because of the bias in the simulation results, the combination of drought and future pumpage could result in no discharge at Barton Springs. Additional scenarios were simulated that included current pumpage and no pumpage. These simulations indicate that with current pumpage, spring discharge will decrease to levels similar to those calculated for the end of the 1950s drought (11 cfs). No pumpage resulted in discharges as low as 17 cfs. Actual flows, which may be about 7 cfs because of the bias in the simulation results, indicate that drought conditions similar to those of the 1950s will require no pumpage if spring discharges similar to those of the 1950s are to be maintained.Bureau of Economic Geolog