Aquifer Science

HTGCD General

Cypress Creek Dye Trace Study Summary Report. Arismendez, S.S., Jackson, D., 2024.

Groundwater Conservation District Requirements for Protecting Water Quality, Fults, H., 2022.

Preliminary Report on the Installation of Two Multilevel Monitor Wells Near Jacob’s Well, Smith, B. A., and Watson, J.A., 2022.

Potentiometric Surfaces of the Lower and Middle Trinity Aquifer in Southwestern Hays County, Texas, HTGCD, 2022.

Hays Trinity Groundwater Conservation District: District Recharge Review, Webster, P.J., 2021.

Hays Trinity Groundwater Conservation District: Model Scenario: 2011-like Drought with Current Production, Webster, P. J., 2021.

Hays Trinity Groundwater Conservation District: Trinity Recharge in the Northern portion of Hays County, Webster P.J., 2020.

Hays Trinity Groundwater Conservation District: Exempt Well Production Estimation Methodology, Webster, P.J. and Flatten, C., 2020.

Summary of Findings: Upper Onion Creek Dye Trace, Hays County, Texas, Winter 2017, Watson, J.A. and others, 2017.

Geologic Mapping of the Upper Glen Rose Unit 3 (Lower Cretaceous) in the Onion Creek Basin, Western Hays County, Texas: Implications for Recharge to the Trinity Aquifer, Watson, J.A. and others, 2018.

Update on Current Dye-Trace Studies in the Upper Onion Creek Watershed, Hays County, Texas, Interagency Memorandum, 2018.

Comparison of Groundwater Monitoring Data with Groundwater Model Results, GMA 9, Hutchison, W.R., and others, 2014.

Water & Wastewater Facilities Plan for Portions of Hays County West of the I-35 Corridor, HDR Engineering, 2011.

Hydrogeologic atlas of the Hill Country Trinity Aquifer, Blanco, Hays and Travis Counties, Central Texas, Wierman, D.A. and others, 2010.

Woody plant encroachment has increased stream flow in Edwards Plateau, Texas, Texas A&M AgriLife Communications, 2010.

Cypress Creek Project and the Desired Future Conditions Desired Future Conditions Progress for GMA 9, Wierman, D.A., 2009.

Cypress Creek/Jacob’s Well Hydrogeologic Report, Wierman, D.A. and others, 2008.

Analyses of Streamflow Gain-Loss Studies for the Trinity Aquifer in Hays County, Texas, Slade, R.M., Jr. 2007.

Dedicated Monitor Well Technical Data


Skipton Well: Report
Skipton Well: Main Text
Skipton Well: Appendix
Downhole Camera Video
Geophysical Log
Geophysical Log with ASB Annotation


DSISD Well: Report
DSISD Well: Main Text
DSISD Well: Appendix
Downhole Camera Video
Geophysical Log
Geophysical Log with ASB Annotation

Old Hundred

Old Hundred Well: Report
Old Hundred Well: Main Text
Old Hundred Well: Appendix
Downhole Camera Video
Geophysical Log
Geophysical Log with ASB Annotation


Burton Well Report


ESD Well: Report
ESD Well: Main Text
ESD Well: Appendix
Downhole Camera Video
Geophysical Log
Geophysical Log with ASB Annotation

HTGCD Region K

Projected Water Quality Degradation for Bear Creek at Ranch Road 1826 Resulting from Direct Discharge Wastewater Permit Requested by Hays County WCID # 1, April 20, 2006, By Raymond M. Slade, Jr., PH, Certified Professional Hydrologist

Ground-Water Evaluation in and Adjacent to Dripping Springs, Texas, Daniel A. Muller, Texas Water Development Board Report 322, 1990.

Hays County Regional Water and Wastewater Study, Prepared by HDR Engineering for the Hays County Water Development Board, 1989.

Regional Water System Study for the City of Dripping Springs, Prepared by Turner, Collie & Braden for the City of Dripping Springs, 1988.

HTGCD Region L

Evaluation for the Development of a Jacob’s Well Groundwater Management Zone in Hays County, Texas, July 2019

Cypress Creek/Jacob’s Well Hydrogeologic Report – December,2008
Title Page thru Chapter 6
Chapter 7 Text  Figures (A)  Figures (B)
Chapter 8 thru Tables
Appendix 1  Appendix 2  Appendix 3  Appendices 4-5

Hydrogeological characterization of baseflow to Jacob’s Well spring, Hays County, Texas, Sarah C. Davidson, Thesis for Master of Science in Geological Sciences, The University of Texas at Austin, December 2008

Wimberley Regional Wastewater Planning Study, Prepared by Guadalupe-Blanco River Authority and R.J. Brandes Company, 1996.

Ground-Water Conditions of the Trinity Group Aquifer in Western Hays County, (Wimberley Woodcreek Area), Muller, Daniel A., Wesley McCoy, Texas Water Development Board Report LP-205, 1987.


A Streetcar Named Desired Future Conditions:The New Groundwater Availability For Texas
Robert E. Mace, Rima Petrossian, Robert Bradley, William F.Mullican, III
Texas Water Development Board, Austin, Texas 78711-3231
State Bar of Texas
7th Annual The Changing Face Of Water Rights In Texas
May 18-19, 2006
San Antonio
Chapter 3.1

Mace, Robert E., William F. Mullican, III, and Shao-Chih (Ted) Way, 2001, Estimating groundwater availability in Texas (PDF) in the proceedings of the 1st annual Texas Rural Water Association and Texas Water Conservation Association Water Law Seminar: Water Allocation in Texas: The Legal Issues.” Austin, Texas, January 25-26, 2001

Mace, Robert E., Ali H. Chowdhury, Roberto Anaya, Shao Chih (Tec) Way, September 2000. Groundwater Availability of the Trinity Aquifer, Hill Country Area, Texas: Numerical Simulations through 2050
Texas Water Development Board Report 53.

Borehole Geophysical Techniques for Determining the Water Quality and Reservoir Parameters of Fresh and Saline Water Aquifers in Texas, TWDB Report 343 – by Hughbert A. Collier, June 1993.

Bluntzer, Robert L., 1992, Evaluation of the Ground-Water Resources of the Paleozoic and Cretaceous Aquifers in the Hill Country of Central Texas. (PDF)
Texas Water Development Board, Report 339.


Geologic framework and hydrogeologic characteristics of the Edwards Aquifer outcrop, Hays County, Texas; John A. Hanson and Ted A. Small; U.S. Geological Survey, Water-Resources Investigations Report 95–4265, in cooperation with the Edwards Underground Water District, 1995.

Edwards-Trinity Aquifer System, Oklahoma, Texas; Text & Figures,  USGS Ground Water Atlas of the United States, HA 730-E  Figures

Engineering Assessment and Environmental Inventory and Issues Report Artifical Recharge Enhancement Onion Creek, Hays County, Texas; Prepared for the BS/EACD by the TWDB, 1992.

Other Sources