The Dockum Aquifer, West Texas

Robert G. Bradley, P.G.Texas Water Development

Board

Geologic Setting

• Cooper Canyon– Reddish-brown to orange siltstone and mudstone

with lenses of sandstone, and conglomerate• Trujillo

– Gray, brown, greenish-gray, fine to coarse-grained sandstone and sandy conglomerate with thin gray and red shale interbeds

• Tecovas – Variegated, sometimes sandy mudstone with

interbedded fine to medium grained sandstones.• Santa Rosa

– Red to reddish-brown sandstone and conglomerate.

North-South Cross Section

Northern Cross Section

Central Cross Section

Southern Cross Section

Approximate water-level

elevations in the Dockum

aquifer 1981-1996

Legend

Contour interval = 200 feet Elevation in feet above sea level

2400

2600

PECOS

REEVES

CROCKETT

GAINES

HALE

DALLAM

IRION

LAMB

OLDHAM

UPTON

LYNN KENT

COKE

HARTLEY

FLOYD

ANDREWS

REAGAN

WARD

NOLAN

TERRY GARZA

ECTOR

TOM GREEN

DEAF SMITH

FISHER

MOORE

MOTLEY

MARTIN

BAILEY

POTTER

CRANE

CARSON

SCURRY

CROSBY

CASTRO

BORDEN

PARMER

DICKENS

MIDLAND

RANDALL

SWISHER

BRISCOE

DAWSON

HOWARD

HOCKLEY LUBBOCK

SHERMAN

WINKLER

MITCHELL

STERLING

YOAKUM

LOVING

HANSFORD

COCHRAN

GLASS-COCK

ARM-STRONG

HUTCHIN-SON

3400

3000

3800

220034

00

2600

3800

0 50Miles

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0 50Miles

Distribution of Total Dissolved

Solids

1985- 1996

<5,000 mg/l TDS

>10,000 mg/l TDS

D

!TDS sample collected in accordance with procedures in TWDB UM-51 (1991)

TDS sample not collected in accordance with procedures in TWDB UM-51 (1991)

0 50Miles

Salinity hazard for areas

overlying the Dockum aquifer

Salinity hazard area

Historical water use from

the Dockum aquifer

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

1994 1995 1996 1997 1998 1999 2000

Year

Gro

undw

ater

Use

(acr

e-fe

et)

Municipal

Manufacturing

Mining

Irrigation

Livestock

Conclusions

• Recoverable water in sandstone/conglomerates

• Locally important where sufficient sandstone thickness is present

• Recharged by precipitation on outcrop and by leakage in confined areas

• Regional flow to east and southeast• Poor quality (high TDS and Salinity)