Bringing Back Comanche Springs An Analysis of the History, Hydrogeology, Policy, and Economics Report: 2020-08 December 2020 Authors: Robert E. Mace, Ph.D., P.G. The Meadows Center for Water and the Environment - Texas State University Sharlene Leurig, Texas Water Trade Harry Seely, WestWater Research Douglas A. Wierman, P.G., Blue Creek Consulting LLC A report for the National Fish and Wildlife Foundation, the Fort Stockton Convention and Visitors Bureau, and the Cynthia and George Mitchell Foundation. Front Cover Photo: Historic postcard of the Comanche Spring pool and bath house circa 1947 (postcard from the personal collection of Robert Mace). Back Cover Photo: Beauty pageant at Comanche Springs during the Water Carnival with the Big Chief Spring in the background (taken in 2014 by Sarah Wilson). Bringing Back Comanche Springs An Analysis of the History, Hydrogeology, Policy, and Economics Authors: Robert E. Mace, Ph.D., P.G. Executive Director, The Meadows Center for Water and the Environment - Texas State University Sharlene Leurig, CEO, Texas Water Trade Harry Seely, Principal, WestWater Research Douglas A. Wierman, P.G. President, Blue Creek Consulting LLC December 2020 Report: 2020-08 601 University Drive, San Marcos Texas 78666 512.245.9200 | [email protected] | www.MeadowsWater.org The use of brand names in this report does not indicate endorsement by the authors, the authors’ employers, or the funders. Geoscientist Seals The contents of this report document the work of the following Licensed Texas Geoscientists: The seal appearing on this document was authorized on June 26, 2020 by Robert E. Mace The seal appearing on this document was authorized on June 26, 2020 by Douglas A. Wierman, P.G. Mr. Wierman contributed to the content on describing the geologic setting; aquifers; and pumping, desired future conditions, and modeled available groundwater. Dr. Mace contributed to these sections and all other hydrogeologic work and review. The Leon Springs are the real thing. Messrs Beeman and Mills can show, In Summer, Fall, Winter, and Spring, What the Leon Valley will grow. The alfalfa hay, which begins coming in May, Is of the purest emerald green. When prices are right, it finds its way To distant and less favored scenes. The cattle are fine, and so are the swine, And the horses are of noble strain. The men, well, they are two of a kind, None better from Texas to Maine. -Anonymous Published in the Fort Stockton Pioneer on April 9, 1915. Fort Stockton sign at the Chamber of Commerce in For Stockton (taken on August 22, 2008 by Robert Mace). CONTENTS Executive Summary 13 1.0 Introduction 15 2.0 Study Area 16 3.0 A Series of Springs 18 4.0 Hydrogeology 22 4.1 Edwards-Trinity (Plateau) Aquifer 26 4.2 Dockum Aquifer 27 4.3 Rustler Aquifer 27 4.4 Capitan Reef Complex Aquifer 27 4.5 Cross-Formational Flow 28 5.0 Use and Development 31 5.1 Pre-Irrigation 31 5.2 Spring Irrigation 34 5.3 Recreation 37 5.4 The First Wells 38 5.5 Pumps and Pumping 40 5.6 Impacts from Groundwater Production 41 5.6.1 pre-1935 42 5.6.2 1935 through 1947 42 5.6.3 post-1947 43 5.6.4 Decreasing Flows, Increasing Tensions, and a Lawsuit 45 5.6.5 Low Flow to No Flow, Declining Water Levels 49 6.0 The Return of the Springs 51 7.0 Groundwater Managemen 53 8.0 Groundwater Export? 60 9.0 Bringing Back Year-Round Springflow: How Much Pumping for How Much Flow? 63 9.1 How Much Springflow Is Needed? 63 9.2 How Much Does Pumping Need to Be Reduced? 64 9.2.1 Using the Water Budget 65 9.2.2 Using the Groundwater Model 69 10.0 Economics 73 10.1 Management Zone 1 Groundwater Permits 73 10.2 Initial Groundwater Volume Target 77 10.3 Alternatives for Reducing Groundwater Pumping 77 10.3.1 Leasing Full Season Permits 77 10.3.2 Leasing Partial Season Permits 78 10.3.3 Purchasing Permits 78 10.3.4 Improving Irrigation Efficiency 78 10.3.5 Switching Crops 78 10.3.6 Switching Sources 79 10.4 Preliminary Recommendations 79 10.4.1 Phased Approach 80 10.4.2 Target Wet Water 80 10.4.3 Pursue Multiple Alternatives 80 10.5 Funding Groundwater Conservation in the Comanche Springs Contributing Zone 81 10.5.1 WaterSMART 81 10.5.2 U.S. Fish and Wildlife Service Section VI 82 10.5.3 Natural Resources Conservation Service 82 10.5.4 Texas Water Development Board Agricultural Conservation Program 83 10.5.5 State Revolving Funds 83 10.5.6 State Water Implementation Fund for Texas 84 10.5.7 Annual Revenues—Pool Entry Fees 84 10.5.8 Annual Revenues—Tax Revenues from Increased Non-Local Spending 85 10.5.9 Annual Revenues—Water Sales 86 10.5.10 Municipal Bonds 87 10.5.11 Outcomes-Based Bonds 88 10.5.12 Private Equity 89 10.6 Leveraging These Sources 90 11.0 Groundwater Export 91 12.0 Recommendations 92 12.1 Hydrohistory 92 12.1.1 Research the pre-1920 flow measurements 92 12.1.2 Research Leon Springs flow data 92 12.1.3 Research the history of the Improvement District including the history of wells in its jurisdiction 93 12.2 Hydrogeology 93 12.2.1 Continuously monitor springflow at Comanche Springs 93 12.2.2 Refine estimates of the proportion of young and old water in the aquifer, including irrigation return flows 93 12.2.3 Revisit pumping estimates 93 12.2.4 Research the hydrogeology of Comanche Creek north of Interstate-10 94 12.2.5 Increase the resolution of stress periods in the model from annual to monthly 94 12.2.6 Revise pumping, recharge, and inflow in the model 94 12.2.7 Develop a lumped parameter model 94 12.2.8 Evaluate the potential effects of a warming climate on the system 94 12.2.9 Assess springflow at Diamond Y Springs 94 12.2.10 Evaluate the composite hydrograph for the Leon-Belding Irrigation Area 95 12.3 Water Market 95 12.3.1 Establish a leasing market for agricultural water 95 12.3.2 Identify most-preferred alternative aquifer in Management Zone 1 95 12.3.3 Evaluate appropriate locations for aquifer storage and recovery 96 12.3.4 Amend surface water rights on Comanche Creek to enable a broader array of uses 96 12.3.5 Form a special purpose entity to fund spring restoration 96 12.4 Policy 96 12.4.1 Remove the South Coyanosa Springs area from Management Zone 1 96 12.4.2 Consider limiting permits rather than pumping 97 12.4.3 Set desired future conditions for management zones and use the sub-regional model to evaluate the modeled available groundwater volumes instead of the regional model 97 12.4 Next Steps 97 13.0 Conclusions 98 14.0 Acknowledgments 100 15.0 References 101 LIST OF APPENDICES Appendix A: Estimation of Seasonal Discharge (2008–2010) from the Formerly Perennial Comanche Springs 115 Appendix B: List of Defendants and Special Defendants in the District Court Case 129 Appendix C: Flow Measurements Taken at Comanche Springs During this Study 130 Appendix D: Natural Pool Morphology 131 Appendix E: Springflow Deficit Approach for Estimating Pumping 151 LIST OF FIGURES Figure 2.1 Study area 17 Figure 3.1 Study area showing springs, Leon Dam, and the Belding Fault 19 Figure 3.2 Comanche Springs 20 Figure 4.1 Hydrogeologic section of the study area 23 Figure 4.2 Major geologic structural features in the greater Pecos County area 24 Figure 4.3 Location for the cross-section 24 Figure 4.4 An approximately east-west cross-section through the study area 25 Figure 4.5 An approximately north-south cross-section through the study area 25 Figure 4.6 Major and minor aquifers in the study area 26 Figure 4.7 Groundwater levels in Edwards-Trinity, Rustler, and Capitan Reef aquifers 29 Figure 5.1 Discoloration of alluvium in Comanche Creek downstream from Comanche (and other) Springs 32 Detail of the artificial ciénega built by Texas Parks and Wildlife Department at San Solomon Figure 5.2 32 Springs Figure 5.3 A survey from 1875 showing the original irrigation ditches 35 Figure 5.4 Primary irrigation ditches in the Fort Stockton area circa 1902 36 Figure 5.5 Evolution of the swimming hole at Big Chief and Government springs 37 Six wells drilled between 1916 and 1917 around Leon Springs by the Leon Springs Irrigation Figure 5.6 39 Company Photograph of the first pumping well drilled in the Leon-Belding area by the Davenport Figure 5.7 40 Irrigation Land Associates Figure 5.8 Springflow at Comanche Springs from 1941 to 1965 43 Figure 5.9 Spring flow at San Pedro Spring 44 Figure 5.10 Composite hydrograph from wells in the Leon-Belding Irrigation Area 44 Figure 7.1 Groundwater management zones in the Middle Pecos Groundwater Conservation District 55 Figure 7.2 Management Zone 1 55 Modeled available groundwater, permitted production, and recent production for the Edwards- Figure 7.3 58 Trinity Aquifer in Groundwater Management Area 7 Modeled available groundwater, permitted production, and recent production and for the Figure 7.4 58 Rustler Aquifer Modeled available groundwater, permitted production, and recent production and for the Figure 7.5 59 Capitan Reef Aquifer Figure 9.1 Estimates of pumping in the Leon-Belding Irrigation Area and Management Zone 1 68 Historical pumping in the Harden and others (2011) model for Management Zone 1 and seven Figure 9.2 71 scenarios of projected pumping Simulated flow at Comanche Springs for the historical pumping in the Harden and others Figure 9.3 72 (2011) model for Management Zone 1 and for seven scenarios of projected pumping Figure 10.1 Modeled contributions of groundwater storage to springflow at Comanche Springs 74 10 \\ THE MEADOWS CENTER FOR WATER AND THE ENVIRONMENT BRINGING BACK COMANCHE SPRINGS // 11 Permitted volume and annual groundwater use in Management Zone 1 from 2008 through Figure 10.2 74 2016 Figure 10.3 Irrigated