The document outlines practical considerations for developing brackish groundwater resources in Texas, noting that an estimated 2.7 billion acre-feet of brackish groundwater exists statewide but requires significant characterization. It discusses the need to balance brackish groundwater production with impacts to freshwater resources and mentions challenges defining legally binding production zones. Production must follow rules to prevent waste, promote conservation, and control subsidence while allowing highest practical usage of groundwater.

1. James Beach, PG
LBG-Guyton Associates
August 27, 2015

2. Outline
 Practical side of brackish development
 Brackish groundwater volumes
 Management issues and brackish groundwater
production zones
 Things to watch

3. ~40,000 wells
Deep saline units not included
Texas Brackish
Groundwater

4. West Texas

5. “ The complex nature of solution trough………..
The base of the formation is often difficult, if not
impossible, to determine.”
“It is not uncommon to encounter a significant
accumulation of clay in some wells. However,
correlation of individual lithologic units over large
distances is, at best, tenuous.”
-BRACs Pecos Valley Aquifer report
TWDB BRACs

6. Boring Location
BRACs Report: Base of Pecos Valley Alluvium

7. Base of Alluvium
Base of Alluvium

8. “The technique of using geophysical well log correlation was
inherently biased toward a signature that indicated a coarse,
unconsolidated geological unit overlying a more uniform
siltstone or shale unit. This bias may have precluded us from
including basal fine-grained deposits in the Pecos Valley Alluvium
that are almost indistinguishable from the underlying Triassic
and Permian units.”
-BRACs Pecos Valley Aquifer report

11. Characterization Questions
 On a limited budget………….
 How many wells?
 How deep?
 Desired water quality for treatment?
 Law of Diminishing Returns

12. Field Investigations
 Test Drilling
 Water Quality Assessment
 Aquifer Pumping Tests

13. Brackish Considerations
 Areal extent and productivity of brackish aquifer
 Cost of treatment
 Methods of concentrate management

14. Practical Considerations
 Brackish groundwater should be considered as an
alternative new supply in some areas
 Significant portion of brackish may not be in BGPZ
 Feasibility and cost depend on many site-specific
factors
 Financial, regulatory, hydrogeologic and engineering
issues should be considered simultaneously during
all phases of the project

15. Take Home on Practical Issues
 In many places, brackish groundwater still requires
significant characterization
 Typical groundwater development concepts still
apply
 Significant investment is generally required to
develop a brackish project

16. Brackish Volumes

17. Estimated Brackish Volumes in Texas
2.7 Billion AF !!

18. 2.7 Billion AF

19. Unconfined
Confined

21. Brackish Groundwater Availability
Region
Total Estimated Volume of
Brackish Groundwater “In Place”
in all Aquifers
(acre/feet)
Total Minimum Confined
Volume of Brackish Groundwater
(acre/feet)
A- Panhandle 19,072,000 27,600
B- Region B 14,528,000 7,000
C- Region C 84,864,000 84,900
D- Northeast Texas 55,712,000 71,300
E- Far West Texas 125,004,800 377,600
F- Region F 371,548,800 1,299,500
G- Brazos 195,113,600 426,800
H- Region H 192,912,000 470,500
I- East Texas 195,432,000 437,400
J- Plateau 8,515,200 122,600
K- Lower Colorado 201,080,000 872,200
L- South Central Texas 416,576,000 1,191,200
M- Rio Grande 394,848,000 1,220,900
N- Coastal Bend 331,040,000 1,368,800
O- Llano Estacado 91,611,200 151,600
P- Lavaca 7,800,000 25,900
Total 2,705,657,600 8,155,800

22. Brackish Volumes in Texas

23. Balancing test
Highest Practicable Level
of Groundwater
Production
Conservation,
Preservation, Protection,
Recharging, and
Prevention of Waste of
Groundwater, and Control
of Subsidence
23

24. Brackish Groundwater Production
Zone Issues
 Balancing desire to use brackish with long-term
impacts
 “significant” impact?
 extent of BGPZ
 How to implement production in BGPZ
 What if BGPZ does have significant impact on
freshwater supplies
 Details of BGPZ in non-district areas

25. Pecos Valley MAGs

26. Looking Forward for Brackish
 More Characterization Needed
 True value of water will be better identified
 Local economies play important role
 Strongly held viewpoints and beliefs (and water
still flows toward money)
 More Proactive Mitigation?
 Petitions and lawsuits
 More clarity with time….

27. LBG-GUYTON ASSOCIATES
James Beach, P.G.
jbeach@lbg-guyton.com
(512) 327-9640
Austin San Antonio Houston