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Desired Future Condition (DFC) Presentation
1. 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
2. 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
3. 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
4. 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.
5. 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.
6. 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)
7. 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
8.
9. Major and Minor Aquifers of
GMA #9
• Edwards (BFZ)
• Edwards-Trinity (Plateau)
• Trinity – Upper, Middle and Lower
• “Paleozoics”
– Ellenburger-San Saba
– Hickory
– Marble Falls
10. 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
11. 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
20. Hydrogeology of Jacob’s Well and
Cypress 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
21. 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
22. 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
23. Hill County Trinity GAM
2000 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
24. 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 Edwards
Gains to to Edwards aquifer
Aquifer Aquifer
Storage (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
25. 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
31. 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?
32. 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.
33. GMA
Allowable
Designated Public
Pumping
Reps
Implementing
Setting Policies and
GMA DFCs Procedures
Determining District
TWDB Rules & Bylaws Enabling
MAGs Legislation
By Aquifer
Distributing District TWC
TWDB MAGs to Management Chapter 36
GCDs/Cty’s Plan 2010
Joint Regional Planning GCD Processes Statutes
34. 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)
35. 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
36. 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
37. 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
38. 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
39. 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
40. Impact of Exempt Use Growth
2008 GW Production
2371, 42%
Exempt Uses
Non-Exempt Uses
3300, 58%
41. 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%
42. 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?
43. 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?)
44.
45.
46. 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
1060
Water 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
47. 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
48. Where Does GMA-9 Go From
Here?
More Assessments
More Public Input
More Decision-making
More Recommendations
Complete process in 2009
