1. Groundwater Availability as a Matter of Law: A Discussion of the Statutory Model for Quantifying the Resource and Determining Water Availability presented by Michael A. Gershon mgershon@lglawfirm.com University of Texas School of Law Energy Center March 5, 2013 816 Congress Avenue, Suite 1900 Austin, Texas 78701 (512) 322-5800 www.lglawfirm.com

2. Groundwater Availability as a Matter of Law

4. Stakeholders-Regulators Groundwater users (utilities, developers, industry, farmers, ranchers, landowners) Groundwater regulators (GCDs, TWDB, TCEQ, RRC, cities, counties) Those who want to protect/enjoy water Plants and animals that depend upon aquatic habitat Downstream interests on receiving streams

5. Groundwater Availability as a Matter of Law

6. CONCEPTS AND TERMINOLOGY Modeled Available Groundwater: the amount of groundwater that TWDB determines may be produced on an average annual basis to achieve a Desired Future Condition - T EX. W ATER C ODE § 36.001 Desired Future Condition: a quantitative description of the desired condition of an aquifer in a Groundwater Management Area (expressed in aquifer level, aquifer volume, or spring flow) at one or more specified future times – adopted in accordance with Texas Water Code § 36.108 - T EX. W ATER C ODE § 36.001 Total Estimated Recoverable Storage: estimated amount of groundwater within an aquifer that accounts for recovery scenarios that range between 25% and 75% of the porosity-adjusted aquifer volume - 31 T EX. A DMIN. C ODE § 356.10

7. Groundwater Availability as a Matter of Law

8. GCDs (97) within GMAs (16)

9. Groundwater Availability as a Matter of Law REGIONAL/STATEWIDE DECISIONS: IT’S ALL ABOUT ADOPTING DFCs (Tex. Water Code § 36.108) GCDs must consider nine (9) factors: 1)aquifer uses or conditions within the GMA, including conditions that differ substantially from one geographic area to another 2)water supply needs and water management strategies included in the state water plan 3)hydrological conditions, including the Total Estimated Recoverable Storage, average annual recharge, inflows, and discharge 4)other environmental impacts, including impacts on spring flow and other interactions between groundwater and surface water

10. Groundwater Availability as a Matter of Law ADOPTING DFCs (continued) 5)impact on subsidence 6)socioeconomic impacts reasonably expected to occur 7)impact on private property rights in groundwater 8)feasibility of achieving the Desired Future Condition 9)any other information relevant to the DFC

11. Groundwater Availability as a Matter of Law The GAM (model) MODFLOW is the U.S. Geological Survey modular finite-difference flow model, which is a computer code that solves the groundwater flow equation. The program is used by hydrogeologists to simulate the flow of groundwater through aquifers. The code is written primarily in Fortran.

12. Groundwater Availability as a Matter of Law TWDB’s Groundwater Availability Model (GAM)

13. Groundwater Availability as a Matter of Law The governing partial differential equation for a confined aquifer used in MODFLOW is: where: K xx, K yy are K zz are the values of hydraulic conductivity along the x, y, and z coordinate axes (L/T) h is the potentiometric head (L) W is a volumetric flux per unit volume representing sources and/or sinks of water, where negative values are extractions, and positive values are injections (T −1 ) S s is the specific storage of the porous material (L −1 ) and t is time (T)

14. Groundwater Availability as a Matter of Law

15. IN PRACTICE  DFC adopted: e.g., 10 feet of aquifer drawdown allowed over 50 years  DFC appeals process  TWDB runs its GAM (model) to calculate the MAG (overall groundwater availability)  Each GCD considers MAG and DFC in developing overall regulatory program  Each GCD considers MAG, DFC and site-specific information when it reviews each permit application

16. Groundwater Availability as a Matter of Law SITE-SPECIFIC DECISIONS: IT’S ALL ABOUT GCD RULES AND PERMITTING (Tex. Water Code §§ 36.113, et seq.) GCDs have regulatory options: - well spacing - correlative rights - historic use - management zones Permitting mandatory (drilling permits, operating permits): “Each GCD, to the extent possible, shall issue permits up to the point that exempt and permitted withdrawals will achieve the DFC.”

17. Groundwater Availability as a Matter of Law SITE-SPECIFIC DECISIONS: IT’S ALL ABOUT GCD RULES AND PERMITTING (Tex. Water Code §§ 36.113, et seq.) GCDs must consider following criteria during permitting: (1)the annual MAG values (2)amount authorized under previously issued permits (3)amount actually produced under permits (4)amount of exempt use (5)precipitation and production patterns (6)whether the proposed use unreasonably affects existing groundwater and surface water resources or existing permit holders (7)whether proposed use is a beneficial use (8)consistency with GCD’s management plan ** Texas Supreme Court’s holding in EAA v. Day/McDaniel

18. Groundwater Availability as a Matter of Law GROUNDWATER AVAILABILITY DETERMINATIONS BY CITIES AND COUNTIES (T EX. L OCAL G OV ’ T C ODE §§ 212.0101, 232.0032) Purpose:confirmation that developer has water prior to approval of plat Requirement:certification by P.G. or P.E. that adequate groundwater is available for subdivision certification must be substantiated by pump test and extensive requirements set forth in TCEQ Rules (30 TAC Ch. 230)

19. Groundwater Availability as a Matter of Law PRIORITIES/ISSUES Defining the Groundwater Resource: Accountability for accurate water levels, spring flow, pumping. Are aquifers replenishable or finite? Water quality? Assessing the demand on the resource: Does demand exceed supply? Is there enough to go around? Who supplies the water? At what cost? Allocating the Resource: Who owns it? How do we allocate it? Is there a market for selling it? How are the markets regulated? Haves vs. have-nots?

20. Groundwater Availability as a Matter of Law PRIORITIES/ISSUES Impacts on the environment Spring flows Source water protection Avoiding intrusion of lower quality water Endangered species …and compare… Impacts on the economy

21. Groundwater Availability as a Matter of Law: A Discussion of the Statutory Model for Quantifying the Resource and Determining Water Availability presented by Michael A. Gershon mgershon@lglawfirm.com University of Texas School of Law Energy Center March 5, 2013 816 Congress Avenue, Suite 1900 Austin, Texas 78701 (512) 322-5800 www.lglawfirm.com