Hays Trinity Hays Trinity Groundwater Groundwater Conservation Conservation

DistrictDistrict

HTGCD Mission HTGCD Mission StatementStatement

““Given the critical importance of water to life and Given the critical importance of water to life and of that part of the water cycle called of that part of the water cycle called groundwater to local families, agriculture, groundwater to local families, agriculture, commerce, stream flows and wildlife habitat, commerce, stream flows and wildlife habitat, the Hays Trinity Groundwater Conservation the Hays Trinity Groundwater Conservation District works to conserve, preserve, recharge District works to conserve, preserve, recharge and prevent waste of groundwater within and prevent waste of groundwater within western Hays County. To help accomplish these western Hays County. To help accomplish these goals the District is charged to gather goals the District is charged to gather information needed for sound decisions, to information needed for sound decisions, to provide that information to citizens and local provide that information to citizens and local agencies, and to insure that groundwater is agencies, and to insure that groundwater is used efficiently and at sustainable rates.”used efficiently and at sustainable rates.”

Texas Priority Groundwater Texas Priority Groundwater Management AreasManagement Areas

1991- Hays Trinity 1991- Hays Trinity became part of Hill became part of Hill County PGMACounty PGMA

2001 – HTGCD 2001 – HTGCD created by 77created by 77thth Legislature (S.B. 2)Legislature (S.B. 2)

2003 – HTGCD 2003 – HTGCD confirmed 2:1 in confirmed 2:1 in popular electionpopular election

Water Administration:Water Administration:Texas Water CodeTexas Water Code

Water Administration:Water Administration:Texas Water CodeTexas Water Code

Chapter 36.0015 says: Chapter 36.0015 says: “Groundwater Conservation “Groundwater Conservation Districts created as provided Districts created as provided by this chapter are the state’s by this chapter are the state’s preferred method of preferred method of groundwater management.”groundwater management.”

Chapter 36.0015 says: Chapter 36.0015 says: “Groundwater Conservation “Groundwater Conservation Districts created as provided Districts created as provided by this chapter are the state’s by this chapter are the state’s preferred method of preferred method of groundwater management.”groundwater management.”

Some Function of GCDsSome Function of GCDs

Provide for local control of GW resources Provide for local control of GW resources in lieu of Rule of Capture (the right to in lieu of Rule of Capture (the right to pump all the GW you can with no pump all the GW you can with no consideration for the impact to other consideration for the impact to other property owners or the eco-systems);property owners or the eco-systems);

Establish GW resource management Establish GW resource management policy for jurisdiction;policy for jurisdiction;

Establish GW rights and issue production Establish GW rights and issue production permitspermits

GCDs are accountable to electorate;GCDs are accountable to electorate;

Single Single Member Member

Districts w/in Districts w/in HTGCDHTGCD

Summary of What the Summary of What the DistrictDistrict

Does Not RegulateDoes Not Regulate Single Household Wells- must register but Single Household Wells- must register but

not permitted or metered by the District; not permitted or metered by the District; No inspection of single household wells No inspection of single household wells

without permission; without permission; Wells used for conventional farming and Wells used for conventional farming and

ranching activities including such ranching activities including such intensive operations as aquiculture, intensive operations as aquiculture, feedlots or poultry operations;feedlots or poultry operations;

Wells used for the dewatering and Wells used for the dewatering and monitoring of lignite production and oil & monitoring of lignite production and oil & gasgas

There are over 6,650 There are over 6,650 wellswells

in the District; in the District; District regulates District regulates

less than 2%. less than 2%.

(Exempt single family residential wells (Exempt single family residential wells and agricultural wells may be drilled on and agricultural wells may be drilled on

anyanyspacing and take water from permitted spacing and take water from permitted

well owners and other exempt well well owners and other exempt well owners)owners)

Al Broun, P.G. Al Broun, P.G. District GeologistDistrict Geologist

Management Plan Management Plan GoalGoal::

Maximize Development Maximize Development of the Trinity Aquifer of the Trinity Aquifer andand Maintain Sufficient Maintain Sufficient Water in the Aquifer to Water in the Aquifer to Maintain 90% of Stream Maintain 90% of Stream

Leakage During A Repeat Leakage During A Repeat of Drought of Record.of Drought of Record.

StratigraphyStratigraphy

Hays Trinity Groundwater Conservation DistrictHays Trinity Groundwater Conservation DistrictTrinity aquifer Water Budget Based on the TWDB Edwards-Trinity Trinity aquifer Water Budget Based on the TWDB Edwards-Trinity

aquifer GAMaquifer GAM(in acre-feet per year)(in acre-feet per year)

Lower Trinity aquifer – Lower Trinity aquifer – Not Included in ModelNot Included in ModelSligo & Hosston FormationsSligo & Hosston Formations

Middle Trinity aquifer•Lower Glen Rose Formation

•Hensel Sand

•Cow Creek Limestone

PumpingPumpingSprings & Seeps

(Stream Leakage)

Springs & Seeps(Stream Leakage)

Upper Trinity aquifer•Upper Glen Rose Formation

Recharge(rainfall infiltration)

Recharge(rainfall infiltration)

Trinityaquifer

Edwardsaquifer

Lossto Edwards

Aquifer(Head Dependant Bounds)

Lossto Edwards

Aquifer(Head Dependant Bounds)

Down-gradientMovement Out

of HTGCD(Horizontal Exchange)

Down-gradientMovement Out

of HTGCD(Horizontal Exchange)

Gains toAquiferStorage

(Storage)

Gains toAquiferStorage

(Storage)

Hammett Shale (aquitard)

TWDB Estimate ofTWDB Estimate ofUseable GroundwaterUseable Groundwater

Total = 3,411 ac-ft per yearTotal = 3,411 ac-ft per yearRegion K: 2,500 ac-ft per yearRegion K: 2,500 ac-ft per year

Region L: 911 ac-ft per yearRegion L: 911 ac-ft per year

Basis of Estimates:Basis of Estimates: TWDB Hill Country Trinity Aquifer GAM, 2000 TWDB Hill Country Trinity Aquifer GAM, 2000

TWDB State Water Plans for Region K & LTWDB State Water Plans for Region K & L

[The GAM’s do not include the resources of the Lower Trinity [The GAM’s do not include the resources of the Lower Trinity

(Sligo / Hoston)] (Sligo / Hoston)]

Hays Trinity Groundwater Conservation DistrictTrinity aquifer Water Budget Based on the TWDB Edwards-Trinity aquifer GAM

(in acre-feet per year)

Lower Trinity aquifer – Not Included in Model•Sligo & Hosston Formations

Middle Trinity aquifer•Lower Glen Rose Formation

•Hensel Sand

•Cow Creek Limestone

Pumping-3,411 ac-ft

Pumping-3,411 ac-ft Springs & Seeps

-2,939 ac-ft(Stream Leakage)

Springs & Seeps-2,939 ac-ft

(Stream Leakage)

Upper Trinity aquifer•Upper Glen Rose Formation

Recharge(rainfall infiltration)

+14,326 ac-ft

Recharge(rainfall infiltration)

+14,326 ac-ft

Trinityaquifer

Edwardsaquifer

Lossto Edwards

Aquifer-13,252 ac-ft

(Head Dependant Bounds)

Lossto Edwards

Aquifer-13,252 ac-ft

(Head Dependant Bounds)

Down-gradientMovement Out

of HTGCD-6,589 ac-ft(Horizontal Exchange)

Down-gradientMovement Out

of HTGCD-6,589 ac-ft(Horizontal Exchange)

Gains toAquiferStorage

+11,866 ac-ft(Storage)

Gains toAquiferStorage

+11,866 ac-ft(Storage)

Hammett Shale (aquitard)

Represents 1956

(Drought of Record)

Represents 1956

(Drought of Record)

Geologic Map & Control Points

Lower Glen Rose, Lower Glen Rose, WoodcreekWoodcreek

Lower Glen Rose, WoodcreekLower Glen Rose, WoodcreekLower Glen Rose, WoodcreekLower Glen Rose, Woodcreek

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SWN 57-56-5--Lat 30-10-42.16627 Lon 98-03-12.38847 Elevation 1117.7 Feet

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Mount Baldy SWN 57-64-

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Lat 30-00-57.6707328 Lon 98-07-0.985026

Elevation 938.633 Feet

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Curtis JohnsonSWN 57-47-901

Lat 30-15-31.7376108 Lon 98-07-47.2901736 Elevation 1229.9 Feet

Groundwater Usage 2003-Groundwater Usage 2003-20042004HTGCD HTGCD

20032003HTGCDHTGCD

20042004Region L Region L

20032003Region K Region K

20032003Region L Region L

20042004Region K Region K

20042004

Annual Rainfall (Austin)-Annual Rainfall (Austin)- 25.45”25.45” 52.68”52.68” 25.45”25.45” 25.45”25.45” 52.68”52.68” 52.68”52.68”

Dripping Springs Water Supply Dripping Springs Water Supply CorporationCorporation

253253 5151 253253 5151

Wimberley Water Supply Wimberley Water Supply CorporationCorporation

664664 564564 664664 564564

AquaTexas/WoodcreekAquaTexas/Woodcreek 591591 558558 591591 558558

Woodcreek Golf CourseWoodcreek Golf Course 192192 7272 192192 7272

Agricultural Usage Agricultural Usage 152152 152152 5959 9393 5959 9393

Other Water Supply CorporationsOther Water Supply Corporations 538538 538538 210210 328328 210210 328328

Residential, (5000 Exempt Wells) Residential, (5000 Exempt Wells) 1,8501,850 1,8501,850 721721 1,1291,129 721721 1,1291,129

Total (acre-feet)Total (acre-feet) 4,2404,240 3,7853,785 2,4372,437 1,8031,803 2,1842,184 1,6011,601

Lower TrinityLower Trinity 283283 283283 110110 173173 110110 173173

Total less Lower TrinityTotal less Lower Trinity 3,9573,957 3,5023,502 2,3272,327 1,6301,630 2,0742,074 1,4281,428

Available WaterAvailable Water 3,7133,713 3,7133,713 1,2131,213 2,5002,500 12131213 2,5002,500

Surplus/Surplus/DeficitDeficit (244)(244) 211211 (1114)(1114) 870870 (861)(861) 1,0721,072

Groundwater Usage 2003-2006Groundwater Usage 2003-2006Production in Acre-FeetProduction in Acre-Feet HTGCDHTGCD

20032003HTGCDHTGCD

20042004HTGCDHTGCD

20052005HTGCDHTGCD

20062006

Annual Rainfall (Austin)-Annual Rainfall (Austin)- 25.45”25.45” 52.68”52.68” 22.33”22.33” 34.70”34.70”

Dripping Springs Water Supply Dripping Springs Water Supply CorporationCorporation

(253)(253) (51)(51) (71)(71) (193)(193)

Wimberley Water Supply CorporationWimberley Water Supply Corporation (664)(664) (564)(564) (653)(653) (693)(693)

AquaTexas/WoodcreekAquaTexas/Woodcreek (591)(591) (558)(558) (666)(666) (649)(649)

Woodcreek Golf CourseWoodcreek Golf Course (192)(192) (72)(72) (87)(87) (113)(113)

Agricultural Usage Agricultural Usage (152)(152) (152)(152) (152)(152) (152)(152)

Other Water Supply Cos ‘Other Water Supply Cos ‘03&’04 were 03&’04 were estimated based on connectionsestimated based on connections

(538)(538) (538)(538) (226)(226) (376)(376)

Residential (~5,000 Exempt Wells) Residential (~5,000 Exempt Wells) (1,850)(1,850) (1,850)(1,850) (2,032) [5,500](2,032) [5,500] (2,139) [5,787](2,139) [5,787]

Total (acre-feet)Total (acre-feet) (4,240)(4,240) (3,785)(3,785) (3,986)(3,986) (4,315)(4,315)

Estimated Lower Trinity UsageEstimated Lower Trinity Usage 283283 283283 283283 285285

Total less Lower TrinityTotal less Lower Trinity (3,957)(3,957) (3,502)(3,502) (3,703)(3,703) (4,030)(4,030)

Available Water in Upper and Available Water in Upper and Middle TrinityMiddle Trinity

3,7133,713 3,7133,713 3,7133,713 3,7133,713

Surplus/Surplus/Deficit Deficit in Upper and Middle in Upper and Middle TrinityTrinity

(244)(244) 211211 1010 (317)(317)

groundwatermanagement

areas

What What House Bill House Bill

17631763sayssays

Regionalizes decisionsRegionalizes decisions Districts over regionsDistricts over regions Permitting targetPermitting target

desired future

conditions

managedavailable

groundwater

(policy) + (science) = groundwater availability

Districts in GMAsdecide Desired Future Conditions

and deliver to TWDB

TWDB provides estimates of Managed Available Groundwater

to districts and regions

Districts and regions includeManaged Available Groundwater

in plans

Example MAG Allocation Example MAG Allocation Scenario (2006)Scenario (2006)

DFC Modeling Results 3411 ac-ftExempt Wells

•Residential (6650) 2560

•Agricultural 152

MAG for Permitting 699

Non-exempt Usage2125

(1425 ac-ft)Wimberley Valley Non-exempt Usage 1500 ac-ft

Requested Non-exempt Irrigation Usage 600 ac-ft

Hays Trinity Hays Trinity Groundwater Groundwater Conservation Conservation

DistrictDistrict