consistent with "Scenario 6" in TWDB GAM Task 10-

Staff Report & Agenda Item Details

9) consistent with "Scenario 6" in TWDB GAM Task 10- 005 Edwards Group of Edwards-Trinity IPlateauJ Allow for no net increase in average drawdown in Bandera and Kendall counties through 2080 Ellenburger-San Saba Allow for an increase in average drawdown of no more than 7 feet in Kendall County through 2080 Hickory Allow for an increase in average drawdown of no more thanT feet in Kendall County through 2080 Additionally, Groundwater Management Area 9 voted to declare certain aquifers andf or portions of aquifers to be non-relevant for the purposes of joint planning, as shown in Table 2. TABLE 2. AQUIFERS AND PORTIONS OF AQUIFERS WHICH WERE DECLARED NON-RELEVANT FOR THE PURPOSES OF IOINT PLANNTNG WTTH|N GROUNDWATER MANAGEMENT AREA 9. Maior or minor aquifer Non-relevant area Edwards (Balcones Fault Zone) Aquifer Entire aquifer (Bexar, Comal, Hays, and Travis countiesl Edwards Croup of Edwards-Trinity [Plateau) Aquifer Portion in Blanco and Kerr counties Ellenburger-San Saba Aquifer Portion in Blanco and Kerr counties Hickory Aquifer Portion in Blanco, Hays, Kerr, and Travis counties Marble Falls Aquifer Entire aquifer (Blanco County) GAM Run 27-014 MAG: Modeled Available Groundwater for the Aquifers in Groundwater Management Area 9 December 8,2022 Page 5 of24 After reviewing the submitted documents, TWDB staff requested clarifications regarding the methodology and assumptions used in the definitions of desired future conditions. Appendix A includes the responses to these clarifications that Groundwater Management Area 9 provided to the TWDB on October L7,2022. METHODS: Hickory and Ellenburger-San Saba Aquifers The groundwater availability model for the minor aquifers of the Llano Uplift Region of Texas (Version 1.01; Shi and others, 2076a,2016b) was used to calculate the drawdown and modeled available groundwater for the Hickory and Ellenburger-San Saba aquifers (Llano Uplift aquifers) within Groundwater Management Area 9. The predictive model files used in the evaluation were originally developed by the TWDB in the previous joint planning cycle for GAM Run t6-023 (fones, 2077). The evaluation in GAM Run 1"6-023 only went to 2070, so the TWDB extended the model files to 2080 for this evaluation. Pumping was distributed evenly across the Kendall County portion of the Llano Uplift aquifers and then varied until the desired future condition was achieved within the accepted tolerance defined by Groundwater Management Area 9. Modeled water levels were extracted for December 2010 [initial water levels equivalent to the final stress period of the historically calibrated model) and December 2080 [stress period 70). Drawdown was calculated as the difference in water levels between those two endpoints. Drawdown averages were calculated by aquifer for each area specified in the desired future conditions. The modeled available groundwater values were determined by extracting pumping rates by decade from the model results using ZONEBUDGET USG Version 1.00 [Pand

This docket item is classified as NEUTRAL (0.0 Score Impact). Routine administrative reports, monthly accounts payable/disbursement registers, minutes approvals, and procedural motions are logged for public transparency but carry zero weight in calculating an official's Roll-Call Freedom Score.