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Hickory UWCD # 1: Groundwater Management Plan Adopted 2024

A certificate for Hickory Underground Water Conservation District No. 1, acknowledging completion of a groundwater management plan.

District Mission

The Hickory Underground Water Conservation District No. 1 (“District”) strives to conserve, preserve, prevent waste, protect, and recharge the underground waters of all aquifers within its legal boundaries, as far as practicable, to minimize the draw-down of the water table and the reduction of artesian pressure within the District Boundaries.

Time Period

This plan becomes effective upon approval by the Executive Administrator of the Texas Water Development Board and remains in effect for a period of five years. The plan may be revised at any time, or after years when the plan will be reviewed, revised, or amended and is approved as administratively complete by the Texas Water Development Board.


At the request of area citizens, the Texas Water Development Board entered an order on December 29, 1975, delineating a subdivision of the Hickory Aquifer Underground Water Reservoir in Concho, Kimble, Llano, Mason, McCulloch, Menard, and San Saba Counties. In November 1981, a petition was submitted to the Texas Water Commission calling for the creation of the Hickory Underground Water Conservation District No. 1 (“District”). At a hearing on June 9, 1982, before the Texas Water Commission, the petition was granted, and the District was created.

The confirmation election required by the state statute was held August 14, 1982; the District was officially established with a 94% approval of voters in those areas of Concho, Kimble, Mason, McCulloch, Menard, and San Saba Counties within the District boundaries.

On August 12, 1999, the petition of creation was amended by the TNRCC (now Texas Commission on Environmental Quality) to include all aquifers within the legal boundaries and management jurisdiction of the District.

On January 11, 2003, landowners of Mason County petitioned the District to annex the remainder of Mason County not currently in the District, and on May 3, 2003, in a special election held at the Mason County Courthouse, the remainder of Mason County was annexed into the District with an approval of 88% of the voters.

Regional Cooperation and Coordination

Regional Water Planning Groups

In 1998 the District was apportioned into two Regional Water Planning Groups established pursuant to §16.053 of the Texas Water Code. Concho, Kimble, Mason, McCulloch, and Menard Counties are located in Region F and San Saba County is in the Lower Colorado Regional Water Planning Group (Region K). The District’s Regional planning responsibilities are within a 46-county area, stretching from Matagorda Bay to the Pecos River in West Texas.

Groundwater Management Area 7

In 2003 the Texas Water Development Board designated the boundaries of 16 groundwater management areas in Texas. The District lies entirely within Groundwater Management Area 7, which encompasses 34 counties and 20 groundwater conservation districts within an area of approximately 42,000 square miles. The groundwater management area was designated for the Edwards-Trinity Aquifer, but also includes all or portions of the minor Lipan-Kickapoo, Hickory, Ellenburger-San Saba, and Dockum aquifers, as well as a small portion of the Ogallala aquifer.

The District participates in the mandatory joint planning process mandated by 36.108 of the Texas Water Code and actively worked with the other 19 GMA 7 Districts to develop Desired Future Conditions (DFCs) for all relevant aquifers in the GMA.

West Texas Regional Groundwater Alliance

The District is a member of the West Texas Regional Groundwater Alliance (WTRGA). The regional alliance consists of seventeen (17) locally created and locally funded Districts that encompass almost 8.75 million acres or 13,000 square miles of West Texas. This West Texas region is as diverse as the State of Texas, making it necessary for each member district to develop its own unique priority management goals and rules to best serve the needs of its constituents. In 1988, four (4) groundwater districts (Coke County UWCD, Glasscock GCD, Irion County WCD, and Sterling County UWCD) signed the original Cooperative Agreement. Since then, the number of groundwater conservation districts in the area has more than quadrupled. The current member districts are:


Coke County UWCDCrockett County GCDGlasscock GCD
Hickory UWCDIrion County WCDLipan-Kickapoo WCD
Plateau UWCD&SDSanta Rita UWCDSterling County UWCD
Sutton County UWCDMenard County UWDLone Wolf GCD
Hill Country UWCDJeff Davis County UWCDMiddle Pecos GCD
Permian Basin UWCDWes-Tex GCD

The WTRGA was created to implement common objectives of coordinating and facilitating the conservation, preservation, and beneficial use of water and related sources. Local districts monitor the water-related activities of farming and ranching, oil and gas, industrial entities, and municipalities.

District Location and Extent

The District is located near the geographical center of Texas and is comprised of approximately 1,683,000 acres in portions of Concho, Kimble, McCulloch, Menard, and San Saba Counties and all of Mason County. In 2003 the District gained approximately 433,000 acres with the annexation of the remainder of Mason County that had not been included when the District was initially created.

Principal industries in the District are listed in the table below1. The District’s economy is based to a large degree on agriculture with 12% of acreage in the District being cropland. Principal municipalities in or near the district boundaries are Brady, San Saba, Mason, and Eden.

ConchoLivestock production, government enterprises, tourism, hunting, fishing
KimbleLivestock production, tourism, hunting, fishing cedar oil and wood
MasonAgriculture, hunting, tourism
McCullochAgribusiness, tourism, manufacturing, mining
MenardAgribusiness, hunting, tourism, minor oil, and gas production
San SabaGovernment enterprises, retail pecan industry, tourism, hunting



The District is within the Colorado River basin and is bisected by the Llano and San Saba Rivers, as well as numerous other creeks, Drainage is typically from west to east.

There are two major geologic features within the District. The Llano Uplift (Central Basin) is in the eastern southern portions of the District. This feature is made up of ancient Cambrian Age rocks ranging in age from 1.0 to 1.2 billion years old and comprised of granite and older metamorphic rocks. The northern and western parts of the District are in the Edwards Plateau Region and are made up of Cretaceous Age limestone, dolomite, and marble.

The District elevation ranges from 1,100 to 2,300 feet above sea level.

Statement of Guiding Principles

The District is created and organized under the terms and provisions of Article XVI, Section 59 of the Constitution of Texas, and Chapter 36 (formerly Chapter 52) of the Texas Water Code, Vernon’s Texas Civil Statues, and the District’s actions are authorized by, and consistent with this constitutional and statutory provision, including all amendments and additions. The District is created for the purpose of conserving, preserving, recharging, controlling subsidence, protecting, and preventing waste and as far as practicable to minimize the draw-down of the water table and reduction of artesian pressure in all aquifers within the District boundaries. In order to carry out its constitutional and statutory purposes, the District has all the powers authorized by Article XVI, Section 59, of the Texas Constitution and Chapter 36 of the Texas Water Code, Vernon’s Civil Statues together all amendments and additions.

The District’s purpose and powers are implemented through promulgation and enforcement of the District's Rules which are adopted and revised under the authority of Subchapter E, Chapter 36, Texas Water Code, and are incorporated herein as part of the District’s Management Plan. A copy of the District's Rules is available on the District's website at and in Appendix C.


Groundwater Resources of the District

Hickory Aquifer2&3

The Hickory Aquifer is the primary source of the District's groundwater, which is used for irrigation, public water supply, industrial, stock, and domestic needs of the people and entities served.

The Hickory Aquifer occurs in parts of the counties in the Llano Uplift region of Central Texas. Discontinuous outcrops of the Hickory Sandstone overlie, or flank exposed Precambrian rocks that form the central core of the uplift. The down-dip artesian portion of the aquifer encircles the uplist and extends to maximum depths approaching 4,000 feet. Most of the water pumped from the aquifer is used for irrigation. The largest capacity wells, however, have been completed for municipal water supply and industrial purposes in the Mason, Eden, and Brady area.

The Hickory Sandstone Member of the Cambrian Riley Formation is composed of some of the oldest sedimentary rocks found in Texas. In most of the northern and western portions of the aquifer, the Hickory can be differentiated into lower, middle, and upper units, which reach a maximum thickness of 480 feet in southwestern McCulloch County. In the southern and eastern extent of the aquifer, the Hickory consists of only two units. Extensive block faulting has compartmentalized the Hickory Aquifer, thus restricting hydrologic connection from one area to another.

Edwards-Trinity Aquifer3

The Edwards-Trinity Plateau Aquifer underlies the Edwards Plateau east of the Pecos River and the Stockton Plateau west of the Pecos River, supplying water to all or parts of 41 counties.

The aquifer consists of saturated sediments of lower Cretaceous age Trinity Group formations. The natural chemical quality of water ranges from fresh to slightly saline. The water is typically hard and may vary widely in concentrations of dissolved solids and bicarbonate. The salinity of the groundwater tends to increase toward the west.

Wells yields are typically low in the easter portion of the Edwards-Trinity, consequently there is little pumpage from the aquifer within the District.

Ellenburger-San Saba Aquifer3

The Ellenburger-San Saba Aquifer underlies 4,000 square miles in parts of 15 counties in the Llano Uplift area of Central Texas. Discontinuous outcrops of the aquifer generally encircle older rocks in the core of the Uplift. The remaining down-dip portion contains fresh to slightly saline water to depths of approximately 3,000 feet below land surface.

Water produced from the aquifer has dissolved solids ranging from 200 to 3,000 mg/l, but usually less than 1,000 mg/l. The quality of water deteriorates rapidly away from the outcrop area. Approximately 20 miles or more down-dip from the outcrop, the water is typically unsuitable for most uses.

Most of the deep municipal wells, which supply the City of Brady, produce an unknown amount of water from the Ellenburger-San Saba sequence of rocks. A substantial portion of the water supply for the City of San Saba is believed to be from the Ellenburger-San Saba and Marble Falls Aquifers.

Marble Falls Aquifer3

The Marble Falls Aquifer occurs primarily in the portions of McCulloch and San Saba Counties within the District. Smaller amounts of water are also used for rural domestic supplies, watering of livestock, and irrigation. Only small portions of Mason and Kimble Counties are affected by this aquifer.

The Marble Falls Aquifer occurs in several outcrops, primarily along the northern and eastern flanks of the Llano Uplift Region of Central Texas. Groundwater occurs in fractures, solution cavities, and channels in the limestone of the Marble Falls Formation of the Pennsylvanian Bend Group. The maximum thickness is 600 feet. Numerous large springs issue from the aquifer and provide a significant part of the base-flow to the San Saba River in McCulloch and San Saba Counties and to the Colorado Rivers in San Saba and Lampasas Counties.

Existing data for the Marble Falls Aquifer show that it contains mostly fresh water in outcrop areas and becomes mineralized a short distance down-dip from the outcrop areas. However, very few data exist to evaluate the brackish water that is present.

Most Marble Falls Aquifer wells produce fresh groundwater in the outcrop, while groundwater becomes highly mineralized within a relatively short distance of the down-dip. However, because the areal extent of the Marble Falls Aquifer is relatively limited, and because much of the existing data indicate that the aquifer has a limited groundwater availability, the Marble Falls Aquifer must be considered a very limited source of brackish groundwater. Due to the presumed deep nature where brackish groundwater would be located, and the low productivity of the aquifer, relative costs are expected to be moderate to high.

Modeled Available Groundwater in District Aquifers4

The District actively participates in joint planning with 19 other groundwater conservation districts (GCDs) in Groundwater Management Area 7 (GMA 7) pursuant to Section 36.108 of the Texas Water Code. The estimates of Modeled Available Groundwater (MAG) for each GCD in GMA 7 are based on the Desired Future Conditions (DFCs) adopted by GMA 7’s member districts on August 19, 2021.

The models used in determining the MAGs and the parameters and assumptions relied upon for the aquifers of the District are described in GAM Run 21-012 Modeled Available Groundwater for the Aquifers in Groundwater Management Area 7 dated August 12, 2022, attached as Appendix B.

Edwards Trinity Plateau Aquifer

There are limited supplies of groundwater from the Edwards-Trinity (Plateau) Aquifer within the boundaries of the District. Any such wells in the District are used almost exclusively for domestic and livestock purposes. Therefore, GMA 7 districts declared the Edwards-Trinity (Plateau) Aquifer is not relevant for joint planning purposes in the District and did not adopt a DFC for the 2020-2070 planning period. Consequently, MAGs are not estimated for the aquifer within the District. A map showing the area of the aquifer is on page 31 of the GAM Run 21-012 MAG in Appendix B.


Ellenburger-San Saba Aquifer4

Total MAG for the Ellenburger-San Saba Aquifer within the District is 12,887 acre-feet/year for reach decade of the 2020-2070 period. See page 41-42 GAM Run 21-012 MAG for total Modeled Available Groundwater and the MAGs for the Ellenburger-San Saba Aquifer located in each county, or portion thereof, within the District. A map showing the area of the aquifer is on page 41 of GAM Run 21-012 MAG in Appendix B.

Hickory Aquifer4

Total MAG for the Hickory Aquifer is 44,483 acre-feet/year for each decade of the 2020-2070 period. See page 45 of Appendix B for the total MAG and the MAGs for the aquifer in each county, or portion thereof, located within the District. A map of the area of the aquifer is on page 44 of Appendix B.

Marble Falls Aquifer4

The Marble Falls Aquifer was declared irrelevant for joint planning purposes within the boundaries of GMA 7. No DFCs were adopted for this aquifer, nor MAGs calculated.

Methodology for Calculating District Water Usage, Surface Water Supply, and Demand

District Water Usage, Surface Water Supply and Demand numbers for counties are allocated to the District in proportion to the percentage of the area of the respective counties within the District as follows:  Concho 11.44%; Kimble 2.55%; Mason 100%; McCulloch 79.92%; Menard 13.51%; and San Saba 55.88%  Refer to Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 in Appendix A.10

Estimate of the Annual Volume of Recharge, the Annual Volume of Water that Discharges from the Aquifer, and the Annual Volume of Flow between Aquifers in the District

For greater depth, please see attached GAM Run 23-019 in the Appendix D or online at


Projected Water Demands

2022 Adopted State Water Plan7


The projected water demands for each water user group in the respective counties for each decade of the planning period are detailed in the 2022 Statewide Water Plan Demands by County ( Refer to Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 in Appendix A.  10

The City of San Angelo was issued a permit to pump water out of the Hickory Aquifer within the District boundaries in 1997.  The City is amping up the well field and treatment expansions, hoping to increase production up to nine million gallons per day in 2026 (approximately 10,000 acre-feet/year). According to the City’s permit, they can pump 10,000 acre-feet a year from 2026 until 2035 and 12,000 acre-feet annually starting in 20368. These amounts are an important piece of the District’s planning for future water demand.

Surface Water Resources of the Hickory UWCD No. 1

The San Saba and Llano Rivers bisect the District; however, only a small amount is used for anything other than livestock or domestic use. Refer to Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 in Appendix A.10

Projected Water Supply Needs7

Refer to Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 in Appendix A.10

Projected needs listed in the Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 indicate that from 2020 until 2070, the need throughout the District will remain steady.  Municipal needs listed in Appendix A, pages 14 and 15 include Junction and Menard which are out of District. Municipal needs within the District are in Mason (Mason County) and Brady (McCulloch County), with a slight decrease in Mason from 2020 to 2070, from 700 acre-feet to 676. In Brady the need increases over the same time period from 1,391 acre-feet in 2020 to 1,414 in 2070. The District works with municipalities, requiring a State approved water conservation plan and drought management plan as well as annual water use reports.

In addition to these projected needs, the City of San Angelo plans to utilize the San Angelo wellfield at full capacity, pumping 10,000 acre-feet/year starting in 2026 and jumping to 12,000 acre-feet annually in 20368.  These figures appear to be well within available supplies, but Federal Drinking Water Standards relating to the levels of radionuclides in much of the Hickory water supply will significantly diminish the availability of groundwater for public water supply purposed. According to the Texas Commission on Environmental Quality, public water supplies in Brady, Eden, and other smaller systems, as well as the water being transported to the City of San Angelo may be impacted by Federal Standards. The City of San Angelo is expanding their treatment facilities to accommodate this issue.


Projected Water Management Strategies in the 2022 Adopted State Water Plan7

Refer to Estimated Historical Groundwater Use and 2022 State Water Plan Datasets for Hickory Underground Water Conservation District No. 1 in Appendix A.10 

Projected water management strategies listed in the TWDB estimated historical  water use/2022 State Water Plan data packet, and located within the District are: Municipal Water Conservation (Eden, Millersview-Doole WSC, Mason, Brady, San Saba, and Richland SUD), Irrigation Conservation (Concho County, Kimble County, Mason County, McCulloch County, Menard County, and San Saba County), Water Audit and Leaks (Millersview-Doole WSC), Subordination (San Angelo System, OH Ivie Non System,  and Brady Creek Reservoir), Mining Conservation (Mason County and McCulloch County), Advanced Water Treatment (Mason and Brady) and Drought Management (North San Saba WSC, Richland SUD, and San Saba County). 

The Projected Water Management Strategies found on pages 17 through 21 emphasize Demand Reduction.  The District works with municipalities requiring water conservation plans and drought management plans in order to reduce demand. The District has developed a series of tracking methodologies and goals documented in this management plan toward the same end.   

Actions, Procedures, Performance, and Avoidance for Plan Implementation

The District will implement the provisions of this plan and will utilize the provisions of this plan as a guidepost for determining the direction or priority for District operations and activities. Operations of the District, all agreements entered into by the District, and any additional planning efforts in which the District may participate will be consistent with the provisions of this plan.

The District has adopted rules relating to the permitting of wells and production of groundwater and continues to review and revise those rules in accordance with the best scientific evidence available and pursuant to changes in state laws and regulations. The rules adopted by the District shall be pursuant to TWC§36 and the provisions of this plan. All rules will be adhered to and enforced. The promulgation and enforcement of the rules will be based on the best technical evidence available.

A copy of the District's Rules is available on the District's website at and in Appendix C


The District shall treat all citizens indiscriminately.  Citizens may apply to the District for discretion in enforcement of the rules on grounds of adverse economic effect or unique local conditions. In granting of discretion to any rule, the Board of Directors shall consider the potential for adverse effects on adjacent landowners.  The exercise of said discretion by the District Board shall not be construed as limiting the power of the District Board.

The District will seek cooperation in the implementation of this plan and the management of groundwater supplies within the District. All activities will be undertaken in cooperation and coordinated with the appropriate state, regional, or local management entity.

Tracking Methodology

The District Manager will provide a report of staff activities to the Board of Directors quarterly at board meetings to ensure management objectives and goals are being achieved.

Management Goals, Objectives, and Performance Standards

Goal 1.0           To provide the most efficient use of groundwater.

Management Objective

1.1       Annually the District will provide educational materials identifying conservation measures for the efficient use of water.  Annually, two (2) District newsletter issues will be published that contain water conservation information. Handout packets with conservation literature will be provided at the annual McCulloch County Soil and Water Conservation Field Day or one other water related function.

                        Performance Standard

1.1a     Number of newsletters published annually containing water conservation information.

                        1.1b     Number of events annually where conservation material was provided

Management Objective

1.2       To monitor groundwater availability over the five-year management period, the District will identify and monitor 50 wells for water levels and obtain annual water levels on the monitored wells.

                        Performance Standard

                        1.2       Number of monitored wells measured annually.

Goal 2.0           To control and prevent the waste of groundwater.

Management Objective

2.1       Once each year the District will lend flowmeters to assist at least one irrigator within the District to evaluate irrigation systems and reduce waste.

                        Performance Standard

2.1       The number of District irrigators who receive loans of flowmeters to assist in evaluating their irrigation systems.

Goal 3.0           Addressing natural resource issues that impact the use and availability of groundwater and are impacted by the use of groundwater.

Management Objective

3.1       Every year the District will conduct water quality tests on at least twenty (20) wells  within the District boundaries.

                        Performance Standard

                        3.1       The number of wells tested each year for water quality.

Goal 4.0           Addressing drought conditions.

            Management Objective

4.1a     Monitor the Palmer Drought Severity Index (PDSI) quarterly and more frequently during abnormally dry conditions, notifying all District public water suppliers of severe drought when they occur 

4.1b     Notify area residents through the District newsletter of severe drought conditions when they occur and advise them that they may find useful information on the current drought status at the TWDB Water Data for Texas drought link at

                        Performance Standards

4.1a     Report the current drought status of the District to the Board of Directors quarterly at District Board meetings

4.1b     Annually report to the Board of Directors the number of times area residents are notified of severe drought conditions in the District newsletter and number of times that letters are sent to public water suppliers warning of severe drought conditions.

Goal 5.0a         Addressing conservation.

            Management Objective

5.1       At least annually the District will provide literature promoting water conservation in a public education presentation.

                        Performance Standards

5.1a     Report to Board of Directors annually the number of times water conservation information was distributed to area residents or in public informational or educational meetings

Goal 5.0b        Addressing rainwater harvesting.

            Management Objective

5.2       The District will display rainwater harvesting manuals at the District office and at least once annually provides notices in the District newsletter that these manuals are available free of charge.

                        Performance Standards

5.2a     Report to the Board of Directors annually on the number of times notice was published in the District newsletter about the availability of rainwater harvesting manuals in the District office.

            Management Objective

5.3       Include information on rainwater harvesting in one public education presentation annually.

                        Performance Standards

                        5.3a     Report to the Board of Directors annually the number of educational presentations that included rainwater harvesting information

Goal 6.0           Addressing the Desired Future Conditions of the District aquifers.

            Management Objective

6.1       Monitor three (3) water levels annually in the Hickory aquifer outcrop and one (1) level annually in the Ellenburger-San Saba outcrop are of the District to determine whether the drawdown objectives of the District’s DFCs are being met. These wells have been chosen as benchmarks because they are not being used/pumped and we have long-standing reliable historical records for them.

                        Performance Standards

6.1       Annual report to the Board of Directors on monitor wells measured annually to determine whether drawdown objectives are being met.

36.1071 (a) Management Goals Not Applicable to the District

Goal 1.0           Controlling and Preventing Subsidence  9

Following District review of the TWDB report Identification of the Vulnerability of the Major and Minor Aquifers of Texas with Subsidence with Regard to Groundwater Pumping, the District concluded that this goal was not applicable to the operation of the District. According to the report conducted by LRE Water, LLC, “Results of the assessment suggest that the Ellenburger-San Saba Aquifer has a low to medium-low risk for future subsidence due to pumping (page 4-141) “ The same study concluded that both the Hickory Aquifer and the Marble Falls have low risks for future subsidence due to pumping (page 4-149 and 4-178).  The report may be accessed at

Goal 2.0           Addressing recharge enhancement.

The Texas Water Development Board, at the request of the District, completed a study of the area within the District to evaluate the possibility of beneficial artificial recharge of this area of the Hickory Aquifer. Evaluation of the Hickory Aquifer and Its Relationship to Katemcy Creek and Its Major Tributaries for Beneficial Recharge, McCulloch and Mason Counties, Texas, is available at the District office.  The study along with subsequent studies does not support an economically feasible recharge program. This goal is not applicable to the operations of the District.

Goal 3.0           Addressing precipitation enhancement.

The District has investigated participation in the West Texas Weather Modification Program which performs cloud-seeding operations out of San Angelo, Texas, but had determined it is not economically feasible.  This goal is not applicable to the operations of the District.


Goal 4.0           Addressing conjunctive surface water management issues.

The City of Brady has halted plans to utilize Brady Lake Reservoir; therefore, this goal is no longer necessary. . This goal is not applicable to the operations of the District.

Goal 5.0           Brush Control

The District recognizes the benefits of brush control through increased spring flows and the

enhancement of native turf which limits runoff. However, most brush control projects within the

District are carried out and funded through the experts at Natural Resources Conservation

Service (NRCS) and ample educational material and programs on brush control are provided by

the Texas AgriLife Extension Service. This management goal is not applicable to the operations

of the District.


1      2022-2023 Texas Almanac, 71st Edition, Texas State Historical Association

2          Aquifers of Texas, Report 380, TWDB, 2011

3          Hickory Aquifer. Minor, TWDB website,

4          GAM Run 21-012 Modeled Available Groundwater for the Aquifers in Groundwater Management Area 7, August 12, 2022


5          2020 Historical Water Use Estimates, TWDB,

6          GAM Run 23-019, TWDB, August 16, 2023


7          2022 Statewide Water Plan, Download Data

8          Hickory Aquifer Overview, City of San Angelo Water Utilities,

9          Vulnerability of Texas Aquifers to Pumping-Induced Subsidence

10           Estimated Historical Groundwater Use and 2022 State Water Plan Datasets; Hickory UWCD #1 by Stephen Allen, TWDB, Groundwater Division October 31, 2023





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