Texas Almanac, 1988-1989 Page: 68
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68 TEXAS ALMANAC 1988-1989
Water Supplies and Needs
The 69th Legislature separated the state's single water agency, the Texas Department of Water Resources, into
two agencies: the Texas Water Commission and the Texas Water Development Board. In addition, the three-
member Texas Water Commission was retained to handle judicial matters, and a six-member Texas Water Devel-
opment Board was retained to establish board policy.
Texas, through Its river authorities, municipalities, water districts and state-level agencies, exercises the
dominant role in development of municipal and industrial water supplies. Approximately 80 percent of the money
invested in the state's water projects has been provided by Texas entitles of government.
Ground-Water Supplies and Use
Aquifers underlie more than half of the area of fresh to slightly saline and is hard. Most of the munici-
Texas. This ground water has long been the principal palities on the Plateau depend on this aquifer for their
source of municipal supplies, but cities now Increasing- water supply. Where the land is arable and yield from
ly depend upon surface reservoirs due to depletion of wells is sufficient, irrigated farming is possible. Prob-
water in aquifer storage. More than half of Texas'total lems exist in those areas where development has ex-
agricultural crop value is produced utilizingground wa- ceeded the capabilities of the aquifer.
terfor irrigation, mainly from the High Plains (Ogallala) Edwards (Balcones Fault Zone) 1L Ground water oc-
aquifer, which underlies most of the Panhandle. curs in fractures, honeycomb zone and solution chan-
Declining water levels, mining and exhaustion of nels in this aquifer that underlies an area along the
ground water, coupled with increasing energy costs, Balcones Fault Zene from Kinney County on the west
are major problems facing the state's water managers . through Bexer County to Bell County on the north. Geo-
today. logically, it is made up of.the Edwards and associated
Majoraquifers in Texas follow (see map): limestones of Cretaceous age and consists of massive to
High Plains (Ogallala) - This formation furnishes thin-bedded, nodular, cherty, gypseous, argillaceous,
practically the only usable quality water on the High white to gray limestone and dolomite of the Comanche
Plains. It is composed of unconsolidated, fine- to Peak, Edwards and Georgetown formations, which have
coarse-grained, gray to red sand, clay, silt and gravel. been downset from the Edwards Plateau due to fault-
Effective recharge from precipitation is small, averag- ing. The aquifer is recharged rapidly by water dis-
ing less than one-quarter inch'yeariy, whereas pump- charged from springs along the edge of the Edwards
ing is heavy, averaging about 5.3 million acre-feet year- Plateau, which then flows in streams that traverse the
Jy. Depletion at the present pumping rate threatens this many faults along the Balcones. The ground water
as a water source for Irrigation. The High Plains (Ogal- moves through the aquifer generally in an easterly,
lala) aquifer supplies Texas' largest Irrigated farming northeasterly direction to points of discharge, notable
region, which produces most of Texas' cotton; grain, of which are Leona, San Antonio, San Pedro, Comal, San
sorghum and other crops. Marcos, Barton and Salado springs, plus numerous
Alluvium and Bolson Deposits - These water-bear- smaller springs. In Bexer County, wells pumping from
ing deposits are scattered throughout many areas In this aquifer are among the world's largest. The water is
the state. They include the Hueco and Mesilla Bolsons, generally of good quality and it is used for public sup-
the Cenezic Alluvium of West Texas, the alluviums of ply, irrigation, industrial, domestic and livestock wa-
North Central Texas, the Leona Alluvium of Tom Green tering purposes. Hydrologically, the aquifer Is unique
County and the Brazoes River Alluvium of Southeast Tex- and is one of the state's most valuable natural re-
as. These deposits consist generally of sand, gravel, silt sources. In the past, the aquifer was adequate to meet
and clay. The quality of the water can range from fresh San Antonio's water needs, but increased growth and
to saline. development in this area necessitate additional surface
In the westernmost Texas region, the Mesilla and water supplies.
.Hueco Bolsons are the primary source of water supply Trinity Group - These basal Cretaceous-age rocks
for the El Paso area, where serious problems'exist re- extend over a large area of North and Central Texas
guarding ground-water depletion and quality degrada- and are composed primarily of sand with interbedded
tion. Other sources of ground-water supply are from clays, limestone, dolomite, gravel and conglomerates.
the SaltBelson (Wildhorse Draw, Michigan Flat, Lobe Flat The Trinity Group is made up of the Twin Mountains,
and Ryan Flat areas), the Red Light Draw Bolson, the Glen Rose and Paluxy formations; however, to the west
Green River Valley Bolson and the Presidio and:Redford and north where the Glen Rose Formation thins or
Belsons. In the Cenozoic Alluvium-region, the Coyonosa pinches out, the Twin Mountains and Paluxy formations
area of northwest Pecos and northeast Reeves counties coalesce and are called the Antlers Fomation. The wa-
and northeastern Ward County are the most productive ter quality is acceptable for most municipal and Indus-
areas of usable quality ground water. Supplies are pro- trial purposes. Extensive irrigation occurs in Coman-
duced from theSeymouraquifer in North Central Texas. che, Eastland and Erath counties. The aquifer has been
Edwards-Trinity (Plateau) --This aquifer underlies overdeveloped in the Dallas-Fort Worth metropolitan
the Edwards Plateau region of Southwest Texas. It con- area and in the vicinity of Waco, where water levels
sists of saturated sediments of the Lower Cretaceous have declined to near 1,200 feet below the land surface.
Comanchean Series made up of sand, sandstone, gravel Carrizo-Wilcox - This aquifer of Eocene age is one
and conglomerate of the Trinity Group (Antlers Sand); of the most extensive water-bearing formations in Tex-
and cherty, gypseous, argillaceous, cavernous lime- as geograpically, and it furnishes water to wells in a
stones and dolomites of the Comanche Peak, Edwards wide belt extending from the Rio Grande northeast-
and Georgetown formations. The ground water general- ward into Arkansas and Louisiana. It consists of hydro-
lyflowssoutheasterly, and neartheedgeofthePlateau, logically connected ferruginous, cross-bedded sand
movement Is toward the main streams where the water With clay, sandstone, silt, lignite and gravel of the Wil-
issues from springs. The water ranges in quality from cox Group and overlying Carrizo Formation. Throughout
[Envira 2177 no 71 t
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Texas Almanac, 1988-1989, book, 1987; Dallas, Texas. (texashistory.unt.edu/ark:/67531/metapth113819/m1/71/: accessed February 22, 2019), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; crediting Texas State Historical Association.