To Update or not to Update? Modeling DFCs - Bill Hutchison
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This document discusses the process of updating Desired Future Conditions (DFCs) for various Groundwater Management Areas (GMAs) in Texas. It provides examples of key issues from the second round of DFC updates for GMAs 2, 3, 4, 7, 11, and 14. For the current third round of updates, it notes that some DFCs may remain unchanged while others are adjusted based on new models, policy changes, or water plan updates. It highlights new model runs being considered in GMA 11 and 14 to help evaluate proposed DFC changes.
To Update or not to Update? Modeling DFCs - Bill Hutchison
- 1. To Update or Not to Update? Modeling DFCs Bill Hutchison, Ph.D., P.E., P.G. January 20, 2020 TAGD Business Meeting
- 2. Planning vs. Management vs. Regulation • Planning (Joint Planning Process) • Desired future conditions (DFC) • Modeled available groundwater (MAG) • Management (GCD Management Plan) • Goal 8 (Addressing in a quantitative manner the desired future conditions (DFC) of the groundwater resources in the District) • Regulation (GCD Rules) • Spacing Rules • Permitting (MAG is one of the factors in permitting)
- 3. Desired Future Condition (DFC) • Quantified conditions of groundwater resources • Specified time or times in the future • Broad Policy Goal • Drawdown • Spring flow • Storage volumes • Updated at least every 5 years
- 4. Model Runs • Simulations of changes in: • Groundwater pumping and/or • Drought conditions • Output examples: • Drawdown • Spring Flows • Storage Volumes
- 5. Model Runs • Simulations of changes in: • Groundwater pumping and/or • Drought conditions • Output examples: • Drawdown • Spring Flows • Storage Volumes DFC
- 6. Model Runs • Simulations of changes in: • Groundwater pumping and/or • Drought conditions • Output examples: • Drawdown • Spring Flows • Storage Volumes MAG
- 7. Important Dates • September 1, 2010 (“first round”) • Statutory DFC deadline • No specific process or documentation requirements • May 1, 2016 (“second round”) • Proposed DFCs must be adopted by this date • First time 2011 process implemented • May 1, 2021 (“third round”) • Proposed DFCs must be adopted by this date • Same 2011 process (no changes)
- 8. Second Round • New Process • Proposed DFC, Public Hearings, Final DFCs • Nine Factors and Balancing Test • Explanatory Report • New Models (examples) • Ogallala and Dockum (GMAs 1, 2, 3, 7) • Rustler (GMAs 3 and 7) • Llano Uplift (GMA 7)
- 9. Third Round (Current) • No change to process • Some DFCs will remain unchanged • Some DFCs will change • New GAMs • Significant policy changes? • Minor adjustments based on changing conditions • Changes in Regional Water Plans? • Changes due to issues associated with monitoring and compliance? • Examples (GMAs 2, 3, 4, 7, 11, 14)
- 10. 2 GMA 2
- 11. GMA 2 • 7 GCDs • 5 Aquifers • Second round key issues • Property rights • Socioeconomic effects • New GAM • Third round • No new model runs • Update explanatory report
- 12. 3 GMA 3
- 13. GMA 3 • 2 GCDs • 7 Aquifers • Second round key issues • New GAMs replaced aquifer analyses • Overlap with GMA 7 for most aquifers • Third round • Reeves County GCD new rules (based on DFC) • No changes/No new model runs • Update explanatory report • Vote on proposed DFC expected October 2020
- 14. 4 GMA 4
- 15. GMA 4 • 5 GCDs • 9 Aquifers • Second round key issues • Documenting nine factors for 6 relevant aquifers with limited data and resources • Third round • No new model runs • Update explanatory report
- 16. 7 GMA 7
- 17. GMA 7 • 21 GCDs • 14 Aquifers • Second round key issues • Pending litigation • Surface water impacts (eastern portion) • New GAMs • Val Verde County (no GCD - relevant or not relevant) • Third round • No new model runs • Update explanatory report
- 18. 11 GMA 11
- 19. GMA 11 • 4 GCDs • 7 Aquifers • Second round key issues • Regional Water Plan Strategies (D and I) • GAM limitations • Third round • Paused until GAM update is complete (mid 2020) • GAM update includes two model runs useful to GMA 11 • Same “drawdown” – new “pumping” • Same “pumping” – new “drawdown” • GMA 11 planning on reviewing these two simulations before deciding if any other simulations are needed
- 20. 14 GMA 14
- 21. GMA 14 • 5 GCDs • Plus 2 subsidence districts and 2 non-GCD counties • 6 Aquifers • Second round issues • New GAM • Second round DFCs resulted in a petition challenging the reasonableness of DFC (Montgomery County)
- 22. GMA 14 Third Round • New Board for Lone Start GCD • Initial model runs for “balancing test” • Wade Oliver – INTERA • Focused on alternative simulations using concept of “available drawdown”
- 24. GMA 14 Available Drawdown Analysis • Available drawdown • Using well records, calculate “available drawdown” • Calculate “median available drawdown” for each county • Find pumping to achieve x % remaining median available drawdown in 2070 • 100 % = roughly same groundwater levels as 2009 • 90%, 80%, 70%, 60%, 50% • After reviewing results at November 2019 meeting, added 75% scenario with some modifications
- 25. Questions and Discussion Bill Hutchison, Ph.D., P.E., P.G. billhutch@texasgw.com 512-745-0599