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DFC Status and Petition Update

Explore the Desired Future Conditions (DFCs) and model simulation results for groundwater resources in Texas, focusing on various aquifers and scenarios. Learn about pumping and drawdown impacts, climatic scenarios, and sustainability considerations.

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DFC Status and Petition Update

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    1. DFC Status and Petition Update Bill Hutchison, Ph.D., P.E., P.G. Director, Groundwater Resources Texas Water Development Board Groundwater 101 November 10, 2010

    2. Topics Statewide summary of DFCs Examples of DFCs Petition update

    3. Desired Future Conditions Deadline to adopt initial DFCs was September 1, 2010 71 DFCs adopted First = December 17, 2007 Last = August 30, 2010 Submittal to TWDB complete All have been found to be administratively complete

    7. Summary of DFCs

    8. Summary of DFCs

    9. Recharge Assumption Summary 4 DFCs considered drought conditions 67 DFCs assumed “average” recharge conditions

    10. Model Runs Simulations of changes in: Groundwater pumping and/or Drought conditions Output examples: Drawdown Spring Flows Storage Volumes

    11. Model Runs Simulations of changes in: Groundwater pumping and/or Drought conditions Output examples: Drawdown Spring Flows Storage Volumes

    12. Model Runs Simulations of changes in: Groundwater pumping and/or Drought conditions Output examples: Drawdown Spring Flows Storage Volumes

    13. DFC Examples GMA 7 – Edwards-Trinity (Plateau) Aquifer GMA 4 – Bone Spring-Victorio Peak Aquifer

    15. DFCs in GMA 7 Edwards-Trinity (Plateau) Aquifer 7 feet of drawdown in 2060 (GMA 7 Average) Summary of how DFC was established

    18. GMA 7 “Vision” Minimize drawdown in east (headwaters area) Provide for irrigation demands in west (significant drawdown)

    19. GMA 7 “Vision” Minimize drawdown in east (headwaters area) Provide for irrigation demands in west (significant drawdown)

    20. “Request” Pumping County-by-county pumping (27 counties) Total GMA 7 “request” = 530,000 AF/yr 2005 GMA 7 pumping = 400,000 AF/yr Assumed average recharge Estimate drawdown in 2060

    22. Six Initial Scenarios Scenario 0 (2005 Pumping) Scenario 1 (“Request” Pumping) Scenario 2 (110% of Request Pumping) Scenario 3 (120% of Request Pumping) Scenario 4 (130% of Request Pumping) Scenario 5 (140% of Request Pumping)

    23. Pumping and Drawdown Summary Scenario 0 400,000 AF/yr 4 feet Scenario 1 530,000 AF/yr 6 feet Scenario 2 586,000 AF/yr 7 feet Scenario 3 639,000 AF/yr 8 feet Scenario 4 692,000 AF/yr 9 feet Scenario 5 746,000 AF/yr 10 feet

    26. July 28, 2010 GMA 7 Meeting Discussed “request pumping” scenario Compare and contrast with continuation of 2005 pumping Compare and contrast with incremental increases GCD representatives developed 5 new scenarios (individual county adjustments) Model runs completed at meeting

    27. Pumping and Drawdown Summary Scenario 6 548,000 AF/yr 7 feet Scenario 7 550,000 AF/yr 7 feet Scenario 8 566,000 AF/yr 7 feet Scenario 9 571,000 AF/yr 7 feet Scenario 10 571,000 AF/yr 7 feet

    28. GMA 7 Adopted Scenario 10 7 feet of drawdown in 2060 (GMA Average) Pumping = 571,000 AF/yr “Request pumping” of 530,000 AF/yr Met predefined “vision”

    31. GMA 4 Bone Spring-Victorio Peak Aquifer

    35. Alternative Conceptual Models Structural Geology Isotope Geochemistry Hybrid of other two

    39. 772 50-Year Simulations 3 models 2 southern boundary conditions 7 climatic scenarios 15 pumping scenarios

    41. Climatic Scenarios Recharge is driven by precipitation Developed alternative precipitation estimates from published dataset of tree-ring data Ni and others, 2002 (U of Arizona) Covers 988 years (1000 to 1988) Developed Seven 50-Year Scenarios

    55. 7 Climatic Scenarios

    56. 15 Pumping Scenarios 3 “constant” pumping 12 “variable” pumping (based on concept of HCUWCD rules) AF/acre limit based on groundwater elevation in a single monitoring well Range in annual pumping: 0 to ~120,000 AF/yr

    57. Results Pumping vs. Groundwater Storage Change Pumping vs. Drawdown (HCUWCD) Pumping vs. Drawdown (Irrigated Area)

    60. If Goal is to Achieve Zero Storage Change for Entire HCUWCD Area

    61. Pumping vs. Drawdown Entire HCUWCD Irrigated Area

    67. Historic Pumping (~80,000 AF/yr) Storage Decline = 1,000 to 22,000 AF/yr HCUWCD Drawdown (50 yr) = 2 to 9.5 ft Irrigated Area Drawdown (50 yr) = -3 to 9.5 ft

    69. Current HCUWCD Limit Net 2.8 AF/ac on Permitted Acreage ~ 95,000 AF/yr of pumping 1948-2002 pumping was 79,000 AF/yr Storage Decline = 4,000 to 31,000 AF/yr HCUWCD Drawdown (50 yr) = 5 to 13 ft Irrigated Area Drawdown (50 yr) = 5 to 20 ft

    70. Sustainable Pumping? Zero Storage Change? Less than a few feet of drawdown? Entire HCUWCD? Irrigated Area of HCUWCD? Worst Case Climate Scenario (50-yr average = 87%)? Average Climate (i.e. 100%)?

    71. HCUWCD Requested a Narrower Range of Analysis Relationship between net pumping and drawdown in 50 years: Average recharge conditions Irrigated area of HCUWCD

    73. Pumping vs. Drawdown net pumping = 1757.5*(drawdown) + 70,925 where: pumping in acre-feet per year drawdown after 50 years in feet

    74. Pumping vs. Drawdown

    75. Pumping vs. Drawdown

    76. Pumping “Comparisons” Before staff finalizes MAG values, TWDB requested comparisons: Current “Groundwater Availability” from State Water Plan Total drainable water in storage Recharge “Maximum Sustainable” pumping

    78. GMA 11 Yegua-Jackson, Sparta, Queen City, Carrizo-Wilcox aquifers DFC adopted on April 13 17 ft drawdown (GMA average)

    79. GMA 11 DFC = 17 ft drawdown (GMA average) Drawdown varies by county and aquifer Differences in pumping Differences in aquifer characteristics DFCs are not defined by geographical areas

    80. GMA 11 Pumping Total Pumping = 543,000 AF/yr Current Use ~ 137,000 AF/yr

    81. GMA 11 Total Pumping (from DFC) Groundwater Availability (SWP) Total Groundwater Storage Recharge Maximum Sustainable Pumping 543,000 AF/yr 548,000 AF/yr 3.1 billion AF 934,000 AF/yr 393,000 AF/yr

    82. Maximum Sustainable Pumping Simulated over 500 years What is the highest pumping that will result in an equilibrium (drawdown levels off)?

    87. Assumption Achieving equilibrium between total inflow and total outflow No consideration to: Springflow reductions Reductions in baseflow Impacts to shallow wells Subsidence

    95. GMA 13 Sparta, Queen City, Carrizo-Wilcox aquifers 23 ft drawdown (GMA average) Drawdown varies by county and aquifer Differences in pumping Differences in aquifer characteristics DFCs are not defined by geographical areas

    96. GMA 13 Pumping Total Pumping = 426,000 AF/yr Current Use ~ 274,000 AF/yr

    97. GMA 13 Total Pumping Groundwater Availability Total Groundwater Storage Recharge Maximum Sustainable Pumping 426,000 AF/yr 468,000 AF/yr 2.1 billion AF 194,000 AF/yr 298,000 AF/yr

    101. Update on Petitions GMA 9 (January 21, 2010) Edwards Group of the Edward-Trinity (Plateau) Aquifer GMA 1 (February 17, 2010) Ogallala and Rita Blanca Aquifers

    102. GMA 9 Edwards Group of Edwards-Trinity Aquifer DFC of zero net drawdown Maximize spring flow Maximize river base flow Petitions filed challenging the reasonableness of adopted DFC Issues with model estimated MAG number

    104. Conceptual Cross Section

    105. State Water Plan Availability (AF/yr) (Kerr County)

    108. Managed Available Groundwater (AF/yr) (Kerr County)

    109. Comparison State Water Plan Groundwater Availability 5,208 AF/yr Estimated 8 to 19 ft of drawdown after 50 yrs Managed Available Groundwater 1,263 AF/yr “Zero” drawdown (Hill Country Model)

    110. Model Comparison Zero Drawdown in Kerr County Hill Country Model 1,263 AF/yr Plateau Model 1,300 AF/yr

    111. Key Findings Reported Groundwater Availability in petitions is not comparable to Managed Available Groundwater The two groundwater models yield similar results in Kerr County

    112. Future Pumping in Edwards Group in Kerr County All pumping is from exempt wells Headwaters GCD does not issue permits for Edwards wells Examined historic trends Projected future exempt pumping

    119. Findings (Kerr County) Managed Available Groundwater of 1,263 AF/yr will be exceeded due to growth in exempt pumping Desired Future Condition (zero drawdown) is not achievable

    120. Recommendation (Kerr County) 9 ft drawdown in 2060 4,000 AF/yr pumping in 2060 12 percent impact to springflow 2,000 AF/yr increased stream recharge

    122. Recommendation (Bandera and Kendall Counties) The Edwards Group of the Edwards-Trinity (Plateau) Aquifer is not relevant Uses are less than 300 AF/yr No permits are issued

    123. GMA 9 Action on TWDB Recommendations Public Hearing held on “new” (recommended) DFC on February 22, 2010 July 26, 2010 meeting: Bandera and Kendall counties – zero drawdown Kerr County – not relevant October 14, 2010 TWDB meeting: No Board comment on “revised” DFCs

    124. GMA 1 Desired Future Conditions in Three Areas Analysis of Historic Pumping Analysis of Petitioners’ Request Northwest counties pumping reduction Hemphill County pumping increase

    127. Historic Pumping Summary Area 1 pumping - 4 counties ~ 800,000 AF/yr (1990s) Area 2 pumping – Hemphill County ~ 3,000 AF/yr (1990s) Area 3 pumping – 13 counties ~ 400,000 AF/yr (1990s)

    129. Northwest Counties (Area 1) Petitioners’ “request”: DFC of 50/50 Result would be reduced pumping 130,000 AF/yr 6.6 million AF over 50 years

    130. Northwest Counties (Area 1) Reduced pumping would result in economic impact Estimated to be $358 million over 50 years

    131. Hemphill County (Area 2) Petitioners’ “request”: DFC of 50/50 Result would be increased pumping Evaluated lateral flow impacts Evaluated impacts to river baseflow and springflow

    136. Recommendation The desired future conditions adopted by the groundwater conservation districts in Groundwater Management Area 1 are reasonable

    137. Post-TWDB Finding of “Reasonable DFC” March 16, 2010 – Petitioners (Mesa Water, L.P. and G&J Ranch) filed suit in Travis County District Court Set aside TWDB decision Find the DFCs are not reasonable Attorney General’s office is handling this on behalf of TWDB

    138. Post-TWDB Finding of “Reasonable DFC” September 2010, Mesa Water, L.P. filed a petition with TCEQ: Issue an order requiring adoption of a single DFC Adopt and equitably enforce rules designed to achieve the DFC Dissolve the boards of directors of the Districts in GMA 1 Dissolve the districts

    139. Next Steps TWDB developing Managed Available Groundwater values Model improvement continuing Legislative session begins January 2011 Potential changes to the process “Next” round of DFCs due in 5 years

    140. Questions?

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