Cypress Creek Project and the Desired Future Conditions Process Negotiating the Bumps at the Intersection of Science and Public Policy Douglas A. Wierman, P.G., Hays Trinity GCD October 1, 2009
Alphabet Soup• GMA – Groundwater Management Area• GCD – Groundwater Conservation District• DFC – Desired Future Condition• MAG – Managed Available Groundwater• GAM – Groundwater Availability Model• TWDB – Texas Water Development Board• DOR – Drought of Record
Outline of Today’s Presentation• Overview of the DFC Process• Hydrogeology of Jacob’s Well and Cypress Creek• Status of GMA #9 DFCs and MAGs• Possible DFC/MAG Implementation Strategies in HTGCD
Overview of the DFC Process• In September, 2005, House Bill 1763 of the 79th Texas legislature became effective. HB 1763 was incorporated into Chapter 36 of the Texas Water Code. No funding made available.• Groundwater planning was regionalized into Groundwater Management Areas (GMAs) which consist of individual GCDs and areas not included in a GCD.• With significant public input, GMAs must establish a Desired Future Conditions for each aquifer in the GMA for the period 2010 through 2060 by September 2010.
Overview of the DFC Process• TWDB, primarily through the use of groundwater availability models, determines how much water can be pumped from the aquifer to achieve the DFC. This volume of water is known as the Managed Available Groundwater, or MAG.• With public input, individual GCDs must develop management strategies and rules to permit groundwater withdrawal up to the MAG.
Desired Future Conditions• A quantitative description of a natural aquifer condition/property as a goal – not well discharges• DFCs are set for all aquifers in a GMA• Aquifer may be subdivided “geographically”• Approved by vote of two thirds of at least two- thirds of the GMA’s GCDs (In GMA #9, as few as 4 of 9 GCDs can determine DFCs for the entire GMA)
Managed Available Groundwater• Managed Available Groundwater – water that will be available to all end users that meets the DFC under applicable regulatory constraints• MAG values are de facto “caps” and the mandatory basis for Regional/State Water Plans• Rules adopting/enforcing MAGs and supporting DFCs are mandatory upon all GCDs in a GMA
Major and Minor Aquifers ofGMA #9• Edwards (BFZ)• Edwards-Trinity (Plateau)• Trinity – Upper, Middle and Lower• “Paleozoics” – Ellenburger-San Saba – Hickory – Marble Falls
GCDs of GMA 9• Bandera County River Authority And Ground Water District• Barton Springs/Edwards Aquifer Conservation District• Blanco-Pedernales Groundwater Conservation District• Cow Creek Groundwater Conservation District• Edwards Aquifer Authority• Hays Trinity Groundwater Conservation District• Headwaters Groundwater Conservation District• Medina County Groundwater Conservation District• Trinity-Glen Rose Groundwater Conservation District• No GCD in Comal or Travis Counties
Hydrogeology of Jacob’s Well and Cypress Creek•Hydrogeologic Setting•Sources of Water to Cypress Creek Base Flow from Jacob’s Well Storm Surge from Aquifer Storm Water Run-off
Local StratigraphyDeveloped by A.S. Broun,District Geologist
Structural Cross Section B to B’ – Cypress CreekDrainageLower Cretaceous Trinity Group, Hays County, Texas
Structural Cross Section B-B’(cropped and enlarged)
Hydrogeology of Jacob’s Well andCypress Creek Takeaways• Base Flow from Jacob’s Well is Cypress Creek• Base Flow originates in the Cow Creek Member of the Middle Trinity Aquifer• Recharge Zone is local and up dip to the west
Status of GMA #9 DFCs and MAGs• GAM 9 has voted and approved DFCs for the Marble Falls, Ellenberger, Hickory and Edwards- Trinity (Plateau)• DFC for Edwards-Trinity (Plateau) set for the preservation of stream flow in the Upper Guadalupe River and it’s tributaries• MAG determined for the Edwards-Trinity (Plateau)• MAG has been appealed
Status of GMA #9 DFCs and MAGs• DFCs to be set for the Upper, Middle and Lower Trinity• TWDB has performed several GAM runs at the request of GMA #9 for Upper and Middle Trinity aquifers, not Lower Trinity Aquifer• 2000 GAM vs. 2009 GAM update
Hill County Trinity GAM2000 GAM vs. 2009 GAM• 2000 GAM included Edwards Trinity Plateau, Upper and Middle Trinity Aquifers• 2009 GAM update added Lower Trinity• All GAM runs to date use 2000 GAM• New GAM runs with 2009 GAM in process
Hays Trinity Groundwater Conservation District Trinity aquifer Water Budget Based on the TWDB Edwards-Trinity aquifer GAM (in acre-feet per year) Recharge (rainfall infiltration) Pumping Springs & Seeps (Stream Leakage) Upper Trinity aquifer •Upper Glen Rose Formation Loss EdwardsGains to to Edwards aquiferAquifer AquiferStorage (Head Dependant Bounds) (Storage) Middle Trinity aquifer •Lower Glen Rose Formation Down-gradient Movement Out •Hensel Sand of HTGCD •Cow Creek Limestone (Horizontal Exchange) Hammett Shale (aquitard) Trinity Lower Trinity aquifer – Not Included in Model aquifer •Sligo & Hosston Formations
GAM Runs HTGCD Middle Trinity• Steady-State (GAM Run 08-70a)• 2008 Current Pumping• GAM Run 08-20, 15-ft drawdown• GAM Run 08-70a (25% > 2008)• GAM Run 08-70b (50% > 2008)• GAM Run 08-30, variable drawdown• GAM Run 08-15, 35-ft drawdown
Do we consider the DOR, or do we close the DOR and just be average?• Should we plan for average precipitation or DOR?• Is sustainability always the best policy? Is it always a possible policy?• Use of drought planning during DOR?
The Real Issue How does the HTGCD allocate a finite resource that has never been fully regulated in an environment where most feel it is their right to pump as much groundwater as they want.
GMA Allowable Designated Public Pumping Reps Implementing Setting Policies andGMA DFCs Procedures Determining DistrictTWDB Rules & Bylaws Enabling MAGs Legislation By Aquifer Distributing District TWCTWDB MAGs to Management Chapter 36 GCDs/Cty’s Plan 2010 Joint Regional Planning GCD Processes Statutes
Possible Allocation Strategies• Management Zones – Recognize that different aquifers and geologic conditions exist – Occurrence and maintenance of stream flow varies across District – Recharge characteristics vary across District (age of water and mining)
Possible Allocation Strategies• Historical Use for Non-Exempt Wells – Water right based on some portion of past production – May be permanent or short term – May be transferable and/or marketable to other areas or other uses
Possible Allocation Strategies• Reasonable Use for Non-Exempt Wells – Current permitting strategy for the HTGCD – Permits based on a “reasonable” amount of water for a specified purpose and duration
Possible Allocation Strategies• Quantifiable Property Rights – Often referred to as correlative right – Based in amount of land owned or controlled – May be transferable (marketable) to other areas or other uses – Could include multiple aquifers beneath a property
Challenges to the HTGCD• Exempt Wells - Residential – Single family domestic use exempt up to 25,000 gpd – Domestic wells can be drilled on any size lot – Current pumpage estimates rely on 330 gpd that results in 42% (2403 ac-ft) of 2008 pumpage – Using the exempt “permitted” amount, domestic wells could use 182,000 ac-ft
Challenges to the HTGCD• Exempt Wells –Agricultural Wells – Exempt from permitting and regulation – Vineyards and orchards are increasing and expected to continue to grow – Currently using 16% of total production
Impact of Exempt Use Growth 2008 GW Production 2371, 42% Exempt Uses Non-Exempt Uses 3300, 58%
Impact of Exempt Use Growth 2033 GW Production with 2% Annual Exempt Growth and 6000 ac-ft MAG 300, 5% Exempt Non-Exepmt 5700, 95%
DFC Process and Cypress Creek Project • HTGCD needs stakeholder feedback on desired condition of Cypress Creek – Are aesthetics of flow the primary criteria? – Is a Jacob’s Well management area necessary? – What level of flow keeps creek off the 303d list? – What is the acceptable level of risk of the creek going dry? – Is the community ready to bear the financial cost of a low risk strategy?
Implementation Schedule• DFCs/MAGs – 1Q 2010• Revise Management Plan – 2Q 2010• Adopt New Rules – 3Q 2010• Rule Implementation – 4Q 2010• GMA 9 meets at least annually to monitor progress towards DFCs• GAM 9 revisits and may reset DFCs in five years (or less?)
Historical Water Level Trends 30º 11 47 North Henly Church Middle Trinity 98º 12 45 West 57-55-401 Depth 460 feet Elevation 1326 feet Colorado watershed 1100 Water Level 1080 Linear Regression 1060Water Level Elevation (feet) 1040 1020 y = -0.14x + 1186 1000 980 960 940 920 900 Jan-99 Jan-00 Jan-01 Jan-03 Jan-04 Jan-05 Jan-07 Jan-08 Jan-02 Month Jan-06
Current Thinking of HTGCD• Due to the nature of the GAM, be conservative at this time• Allow for MAG to be metered out to account for growth of exempt wells• Set up groundwater management zones in critical areas• Account for DOR through drought planning
Where Does GMA-9 Go From Here? More Assessments More Public Input More Decision-making More Recommendations Complete process in 2009