GMA Modeling and Decision Making_James Beach
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This document summarizes the joint planning process for desired future conditions (DFCs) of groundwater management areas in Texas. It discusses that groundwater conservation districts must decide on DFCs that balance highest practical production with conservation, considering factors like existing and future supply/demand, hydrogeology, impacts, and property rights. Districts use modeling to simulate pumping scenarios and assess impacts, with stakeholder input. The process aims to find the right balance between competing objectives, but does not always satisfy all stakeholders.
GMA Modeling and Decision Making_James Beach
- 2. Execu&ve Summary 1. What are we deciding? Ø The Joint planning process 2. How do we decide? Ø Modeling toolbox 3. Who is the decider? Ø You and stakeholders 4. What could possibly go wrong? 2
- 8. Desired Future Condi&ons — allowable water level decline in the future — volume of groundwater remaining in the future — minimum spring flow — water quality goals — allowable subsidence — combinaDons or other aquifer-specific goals — other……. 8
- 11. Assessing Modeling Results — Remaining saturated thickness maps/tables — Percent of Current Water Remaining in Storage — Percent of Available Drawdown above Top of Aquifer — Drawdown — Percent Decline in Water Level — Impact on ExisDng Public Water Supply Wells — Regional impact of Local Pumping changes — Decrease in Springflow (especially in droughts) — Subsidence — Many others… 11
- 12. Simula&on Results Average Drawdown -200 -100 0 100 200 300 400 500 600 2010 2020 2030 2040 2050 2060 2070 Average Drawdown, Feet Hensell Aquifer Average Drawdown - Hill County
- 14. Impact of LOCAL changes on the REGION 14 Woodbine Fredericksburg / Washita Paluxy Glen Rose Hensell Pearsall Hosston Ellis 1,312 192 280 32 0 4 3,181 Hill 604 262 362 118 231 55 3,368 Johnson 711 916 876 586 449 2 1,460 Somervell 0 20 229 3,343 50 1,356 County Increase in Pumping for Run 7 (acre-feet per year)
- 16. Stakeholders — Consult your a_orney — You are the “Decider” — Engage stakeholders early and oben — Document engagement a_empts — Document input from stakeholders — Consult your a_orney — As appropriate, develop modeling scenarios to address stakeholder input — Ask regularly if you have considered the 9 factors as quanDtaDvely as possible — Consult your a_orney 16
- 18. Ongoing Debates about the Process — conceptually sound - but difficult to implement — How to apply regional, long-term DFCs on a local basis today? — leaves districts vulnerable to peDDons/lawsuits — is too complex and is prone to favor local uses over “exports” — doesn’t provide a volume of water that could pracDcably be produced — inappropriately “reverse-engineers” groundwater availability — allows districts to micro-manage local groundwater availability — allows the districts to inappropriately deny permits 18
- 19. Take Home — Two 5-year rounds of planning over a 10-year Dme frame indicate that each GMA focuses on different goals and prioriDes in order to find “the balance” — In some management areas – nobody is happy – some stakeholders feel there is too much impact on springs/streams while groundwater developers think the pumping is too restricDve to support growth — In agricultural areas, maintaining irrigaDon has been a key objecDve, even if aquifer storage is depleted over Dme — In some environmentally sensiDve areas, maintaining springflow is a high priority — ProtecDng the private landowners access to groundwater for domesDc & livestock purposes is criDcal almost everywhere. — In dipping aquifers, finding a balance that protects well owners and streams/ springs in the outcrop while increasing downdip producDon seems to be focus 19