James Beach, PG

LBG-Guyton AssociatesAugust 27, 2015

Outline

� Practical side of brackish development

� Brackish groundwater volumes

� Management issues and brackish groundwater � Management issues and brackish groundwater

production zones

� Things to watch

~40,000 wellsDeep saline units not included

Texas Brackish

Groundwater

West Texas

“ The complex nature of solution trough………..

The base of the formation is often difficult, if not impossible, to determine.”

TWDB BRACsTWDB BRACs

“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

BRACs Report: Base of Pecos Valley Alluvium

Boring Location

Base of Alluvium

Base of Alluvium

“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 that are almost indistinguishable from the underlying Triassic and Permian units.”

-BRACs Pecos Valley Aquifer report

Characterization Questions� On a limited budget………….

� How many wells?

� How deep?

� Desired water quality for treatment?� Desired water quality for treatment?

� Law of Diminishing Returns

Field Investigations

� Test Drilling

� Water Quality Assessment

� Aquifer Pumping Tests� Aquifer Pumping Tests

Brackish Considerations

� Areal extent and productivity of brackish aquifer

� Cost of treatment� Cost of treatment

� Methods of concentrate management

Practical Considerations

� Brackish groundwater should be considered as an alternative new supply in some areas

� Significant portion of brackish may not be in BGPZ� 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

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

Brackish Volumes

Estimated Brackish Volumes in Texas

2.7 Billion AF !!2.7 Billion AF !!

2.7 Billion AF

Unconfined

Confined

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 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

Brackish Volumes in Texas

Balancing test

Conservation,

Highest Practicable Level of Groundwater

Production

Conservation, Preservation, Protection,

Recharging, and Prevention of Waste of

Groundwater, and Control of Subsidence

23

Brackish Groundwater Production

Zone Issues

� Balancing desire to use brackish with long-term

impacts

� “significant” impact?� “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

Pecos Valley MAGs

Looking Forward for Brackish

� More Characterization Needed

� True value of water will be better identified

� Local economies play important role� 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….

LBG-GUYTON ASSOCIATESLBG-GUYTON ASSOCIATESJames Beach, P.G.

jbeach@lbg-guyton.com

(512) 327-9640

Austin San Antonio Houston