U.S. Department of the Interior a U.S. Geological Survey

U.S. Geological Survey

Programs in Texas

The U.S. Geological Survey (USGS) is 

the Federal Government’s primary source 

of data on the quantity and quality of the 

Nation’s water resources, its principal 

civilian map making agency, and its primary provider of information on natural 

hazards and mineral, energy, and biological resources. The USGS makes unbiased 

scientific information available equally to 

all interested parties. 

Most USGS work in Texas involves the 

appraisal of the State’s water resources in 

cooperation with more than 80 local, 

State, and Federal agencies. The foundation of a wide range of hydrologic datacollection and interpretive programs is 

the stream-gaging program. The Texas 

network of streamflow-gaging stations, 

which provides water data for waterresources planning and design, hydrologic research, and operation of waterresources projects, is part of a nationwide 

aggregation of networks that is unique 

because of nationally consistent, prescribed standards by which the data are 

collected and processed. 

The USGS continues to expand collection of data for paper and digital maps. 

The best-known products of the USGS in 

Texas are its 1:24,000-scale topographic 

maps. These maps depict basic natural 

and cultural features of the landscape. 

Maps at this scale (1 inch on the map 

represents 2,000 feet on the ground) are 

useful for civil engineering, land-use 

planning, and natural-resource monitoring, and have long been favorites with 

the general public for a wide variety of 

outdoor uses.

The USGS also continues to monitor 

geologic conditions in Texas associated 

with rare but potentially dangerous 

earthquakes. Recently, the Nation Biological Service (now the Biological 

Resources Division) joined the USGS to 

continue their appraisal of the nation’s 

biological resources.

Monitoring Floods, Droughts, and 

Earthquakes

In fall 1994, the USGS measured major 

floods in the Houston area. The 100-year 

flood (the peak streamflow that has a 

1-percent chance of being equaled or 

exceeded in any given year) was equaled 

or exceeded at 16 of the 43 stream sites 

monitored. By 1996, the opposite 

extreme—drought, severe in places and 

moderate in others—gripped the entire 

State (fig. 1). USGS monitoring of drought 

conditions is as meticulous and intense as 

the monitoring of flood conditions. For the 

first 6 months of 1996 for each of 16 longterm streamflow-gaging stations distributed throughout the State, streamflow volumes, which are a common indicator of 

hydrologic conditions, ranged from 0.2 to 

44 percent of the mean volume. Streamflow volumes for the first 6 months of 1996 

set record lows for 3 of the 16 stations. 

In recent years, the USGS, in cooperation with local, State, and Federal agencies 

in Texas, has made a concerted effort to 

replace outdated monitoring equipment 

with state-of-the-art Data Collection Platforms (DCP’s). The USGS operates about 

320 DCP’s at stream sites throughout the 

State. The DCP’s transmit stream elevations or water-quality data to a satellite, 

which, in turn, transmits the data back to a 

local ground station and into the USGS 

computer system. These data generally are 

transmitted at 4-hour intervals, but all 

DCP’s are being programed to transmit 

data more frequently on a “storm-event” 

basis—a feature that allows streamflow 

data during floods to reach users of the data 

almost instantly. DCP technology, together 

with the Internet-based World Wide Web 

(WWW; see p. 3), is bringing the USGS to 

its goal of making realtime hydrologic data 

available to water managers and the public.

In 1995, a magnitude 5.3 earthquake 

struck the Alpine–Marathon area of Texas. 

The largest historical earthquake, magnitude 6.4, to strike this region occurred in 

1931 near Valentine. Both earthquakes 

caused damage; however, neither was large 

enough to rupture the ground surface. 

Large, surface-rupturing earthquakes (magnitude greater than 6.5) have not occurred 

in west Texas in historic times, but geologic 

Index of Subjects

Monitoring Floods, Droughts, and 

Earthquakes

Water-Quality Trends

U.S.–Mexico Border Activities

New Maps for Texas

National Coal Assessment

Potential for Desertification of the Texas 

High Plains

Texas Earth Science Information on the World 

Wide Web

Earth Science Information Centers

A New USGS Division—Biological Resources

Sung Park/Austin American-Statesman, reprinted 

by permission

Figure 1. Severe drought in Central Texas is 

reflected by the dry, cracked streambed of the 

Pedernales River, July 1996. Mean annual flow of 

the Pedernales near the site of this photograph is 

about 200 cubic feet per second.
100-mile transborder zone

95°

105 100° °

30°

35°

0 100 200 MILES

0 100 200 KILOMETERS

Texas

New Mexico

Chihuahua

Coahuila

Nuevo

Leon

Tamaulipas

Sonora

evidence suggests that they might have in 

prehistoric times. The USGS, in cooperation 

with the Bureau of Economic Geology, has 

recently completed a compilation of data on 

potentially active faults in west Texas and 

adjacent Mexico. The compilation includes 

a conventional map (1:500,000 scale) and 

fully documents published information on 

24 faults with evidence of surface rupture 

within the last 1.6 million years. The compilation is particularly useful for seismic hazard evaluation of regions, such as west 

Texas, that have low seismicity. The compilation is the first of many similar State and 

regional compilations that are planned for 

the United States.

Water-Quality Trends

The USGS has been using age-dated 

bottom-sediment cores from reservoirs, 

wetlands, and estuaries in Texas to evaluate 

historic water-quality trends in upstream 

watersheds. The technique, which was 

developed as a part of the National WaterQuality Assessment Program and subsequently applied in other USGS studies in 

Texas, is particularly useful because appropriate historic water-quality data are lacking for long-term trends assessment.

One of the first sites where the USGS 

applied the technique is White Rock Lake, 

which is a 2-square-mile reservoir in northeastern Dallas. Soils from the watershed 

have been eroding from the land surface 

into streams and subsequently accumulating on the bottom of the reservoir since its 

construction in 1912. By analyzing discrete 

sections of age-dated sediment cores, scientists are able to reconstruct water-quality 

conditions associated with the change from 

agricultural to urban land use and with the 

implementation of more stringent environmental controls. 

For example, a concentration-depth profile of the insecticide DDT in bottom sediments from White Rock Lake with a history 

of deposition indicated (fig. 2) shows that 

DDT was first detected in sediments deposited in about 1942. Concentrations peak in 

sediments deposited in about 1963 and 

decrease by a factor of more than 25 from 

1963 to 1994. Production of DDT in the 

United States began in 1939, peaked in the 

early 1960’s, and declined from the early 

1960’s until 1972 when its use was banned. 

(The U.S. Environmental Protection 

Agency banned all uses of DDT primarily 

because amounts were building up in the 

environment and some cancer tests in laboratory animals showed positive results.) 

Detection of DDT in the upper parts of the 

core indicates that DDT continues to enter 

White Rock Lake, presumably in streams 

that carry soils eroded from the watershed.

U.S.–Mexico Border Activities

With the adoption of the North American Free Trade Agreement, interest in environmental issues associated with economic 

development has increased on both sides of 

the U.S.–Mexico border. Texas is one of 

four States involved in environmental and 

mapping activities in the area along the 

border (fig. 3). The USGS has several relevant initiatives. For example:

• Within the Rio Grande/Rio Bravo international watershed, the USGS is using 

age-dated bottom-sediment cores from 

reservoirs to define historic trends in 

water quality. This approach is being 

applied to Cochiti Lake and Elephant 

Butte Reservoir, New Mexico, International Amistad Reservoir, Texas/Coahuila State, Mexico, International Falcon Reservoir, Texas/Tamaulipas State, 

Mexico, and Laguna Madre, Texas. 

Occurrence and trends in radioactive 

elements in the upper Rio Grande Basin 

and pesticides and trace metals in the 

middle and lower parts of the Basin are 

of particular interest. The study is a 

cooperative effort with the Texas Natural Resource Conservation Commission, 

the El Paso County Water Conservation 

and Improvement District No. 1, the 

U.S. Bureau of Reclamation, and the 

Pueblo de Cochiti Tribe, in consultation 

with the International Boundary and 

Water Commission, the New Mexico 

Environment Department, and the U.S. 

Department of Energy. 

• The USGS is acquiring data needed in 

the border region of Texas to address 

surface-water quality issues that could 

arise as the region continues to develop. 

Figure 2. Con

centration of total DDT in bottom sediments 

of White Rock Lake in Dallas, Texas.

Figure 3. USGS environmental and mapping activities in the Rio Grande /Rio Bravo border 

region are increasing as a result of the North American Free Trade Agreement.
• Data for future constituent trend analyses 

and studies of constituent transport and 

of processes, such as storage and remobilization of sediments and associated 

contaminants, are being collected. Datacollection sites are on the mainstem of 

the Rio Grande (six sites), at the Pecos 

River near Langtry, and at the Arroyo 

Colorado near Harlingen. The new 

water-quality initiative in the basin is 

associated with the USGS National 

Stream Quality Accounting Network, 

the focus of which is on the quantity and 

quality of water that moves within and 

from large river basins. 

• Ground water is becoming increasingly 

important in parts of the border region, 

particularly in the El Paso area where 

freshwater resources are scarce, and the 

Laredo area, one of the fastest-growing 

urban areas in the United States. In the 

El Paso area, withdrawals of ground 

water at rates exceeding those of natural 

recharge have reduced supplies; a 

related effect is land subsidence from 

compaction of the aquifer system. The 

USGS is cooperating with the City of El 

Paso to construct a regional computerized hydrologic model to simulate the 

flow of fresh and saline water and compaction in the aquifer system. The 

model will help the City evaluate future 

water-management schemes. Increasing 

demand for water associated with industrial development and population 

growth in Laredo is causing that city to 

consider ground water as a source of 

additional public supply. Currently 

(1996) the Rio Grande supplies all of 

the municipal water for Laredo. The 

USGS is cooperating with the City in a 

multi-year study of the water-yielding 

potential and the quality of water of 

selected aquifers in the Laredo area.

• The USGS is cooperating with local, 

State, and Federal agencies and other 

organizations in the United States and 

Mexico to develop digital map data for 

the border area. These data support a 

wide range of studies by scientists of 

environmental and resource-management agencies on both sides of the border. Cartographic data are being 

collected within a 100-mile zone on 

each side of the border (fig. 3). In 1996, 

the USGS acquired color-infrared aerial 

photographs for the 100-mile zone on 

the U.S. side of the border. The USGS 

is producing digital orthophotoquads 

from the color-infrared aerial photographs. A digital orthophotoquad combines the image characteristics of a 

photograph with the geometric qualities 

of a map. The digital orthophotoquads 

are useful for revising and upgrading 

various maps, which include the popular USGS 1:24,000-scale topographic 

maps, along the border. 

New Maps for Texas

The USGS is preparing 485 digital orthophotoquads that cover the Texas Gulf Coast 

through a partnership between the Texas 

Natural Resource Conservation Commission, the General Land Office, and the 

USGS. The Texas Natural Resource Conservation Commission uses digital orthophotoquads for various purposes which include 

watershed delineation and building hydrologic models. The General Land Office uses 

digital orthophotoquads to support oil-spill 

prevention and mitigation, to locate sensitive wildlife habitat areas, and to depict current shorelines and land-water contacts.

Digital orthophotoquads are being prepared for much of east and central Texas as a 

result of a partnership between the Texas 

Department of Information Resources and 

the USGS. The Natural Resources Conservation Service, the Consolidated Farm Services Agency, and the USGS are providing 

funding and source materials. The digital 

orthophotoquad data are being held by the 

Texas Natural Resources Information System and also are being archived by the 

USGS for public distribution.

National Coal Assessment

Texas ranks sixth in coal production in 

the United States. Most coal in the Gulf 

Coast area is used as fuel for electric powergenerating plants. In the National Coal 

Assessment in Texas, the USGS is working 

with the Bureau of Economic Geology and 

the Railroad Commission of Texas to provide high-quality, organized information 

and interpretations on the location, quality, 

and quantity of the coal to be mined during 

the next several decades. Particular attention 

is being given to the characterization of hazardous air pollutants identified by the 1990 

Clean Air Act Amendments.

Potential for Desertification of 

the Texas High Plains

 Desertification is the loss of productive 

land. A cooperative study by the USGS, the 

Museum of Texas Tech University, and the 

University of Wisconsin suggests that stabilized sand dunes on the Texas High 

Plains could become active with only slight 

changes in climate. Sand dunes presently 

stabilized by sparse vegetation occur over 

much of the Texas Panhandle and adjacent 

States. Radiocarbon dating and soils studies indicate that more than 1 million acres 

of these dunes have been active in the past 

1,000 years. Historical observations and 

examination of archival aerial photographs 

indicate appreciable areas of dune activity 

in the 19th century and during the 1930’s 

drought. In a 21st century “greenhouse” 

climate or even under natural climatic 

cycles, the potential for reactivation of 

these dunes is high. Activation of presently 

stabilized sand dunes would significantly 

impact grazing, agriculture, and transportation routes in the Texas Panhandle.

Texas Earth Science Information 

on the World Wide Web

The WWW, together with DCP technology, is allowing public Internet access to upto-the-day, if not up-to-the-minute, hydrologic data. The USGS has placed a vast 

amount of hydrologic data and information 

for Texas on the WWW. By using any Internet browser, people can locate, view, and 

retrieve data, text, and graphical information 

generated by the USGS. Public access to the 

data and information is through the Texas 

USGS website at:

http://txwww.cr.usgs.gov/

The Texas USGS website is continually 

evolving and improving. Currently (1996), 

available data include realtime and historic 

streamflow data, water-quality and groundwater data, peak-discharge information, and 

monthly precipitation data (obtained from 

the National Weather Service). For example, a canoeist interested in current streamflow conditions on the Guadalupe River in 

central Texas can access and retrieve an upto-date hydrograph (or tabular data) of flow 

at the USGS streamflow-gaging station at 

Comfort. Each of the online data bases 

allows searching for information by county, 

hydrologic basin, or keyword search.

The Texas USGS website also contains 

regularly updated information about ongoing activities, staff directories, brief 

descriptions of current projects in Texas in 

easily retrievable formats, and links to other 

online sources of natural-resources information. The USGS library in Texas maintains reference material online, which 

includes bibliographic references, report 

abstracts, and the entire contents of selected 

recent publications. 
For More

Information

The USGS also is assisting local and 

State government agencies, universities, and 

private firms to develop and make accessible 

on the WWW spatial data that incorporate 

Federal Geographic Data Committee 

(FGDC) policies and standards. This assistance comes through the National Spatial 

Data Infrastructure (NSDI) Competitive 

Cooperative Agreements Program (CCAP), 

which was established by the FGDC through 

the USGS. One of three recent CCAP grants 

awarded to Texas will enable the University 

of Texas at Dallas, Bruton Center for Development Studies, to establish a NSDI website 

with procedures in place to make its data 

holdings consistent with FGDC standards. 

Earth Science Information 

Centers

Earth Science Information Centers 

(ESIC’s) and their affiliates nationwide provide information to the public about USGS 

programs, products, and technological 

developments. The Texas Natural Resources 

Information System in Austin is an ESIC 

affiliate. As part of the national ESIC network, this office provides information on 

cartography, geography, digital data, remote 

sensing, geology, geophysics, geochemistry, 

hydrology, geohydrology, aerial photography, and land use. It is supported by the 

USGS with reference materials, technical 

assistance, training and outreach activities, 

and access to USGS data bases.

A New USGS Division—

Biological Resources

The USGS in Texas is working with others to provide the scientific understanding 

and technologies needed to support the 

sound management and conservation of the 

State’s biological resources. For example: 

• The USGS is cooperating with government agencies and private entities on 

long-term research at Padre Island 

National Seashore to increase understanding of five species of threatened or 

endangered sea turtles of the northwestern Gulf of Mexico. Data are being 

gathered to help scientists determine 

ways to protect, manage, and recover 

sea turtle populations (fig. 4). 

• A series of studies in partnership with 

State and Federal agencies is ongoing 

at Caddo Lake, which is a unique wetland in northeastern Texas and a critical 

resting site during migration for two 

declining warbler species. 

• USGS scientists serve on technical advisory committees for several oil companies that fund major research projects 

in the Gulf of Mexico. 

• USGS toxicologists contribute to oil-spill 

contingency planning in Galveston Bay 

and other critical areas.

USGS state representative

8011 Cameron Road

Austin, TX 78754

Ph: (512) 873–3000

Fax: (512) 873–3090

Email: dc_tx@usgs.gov

Additional earth science

information can be found by

accessing the USGS Home Page

on the World Wide Web at

http://www.usgs.gov/

For more information on

all USGS reports and products

(including maps, images,

and computerized data), call

1-800-USA-MAPS

The USGS provides maps,

reports, and information to help

others meet their needs to manage,

 develop, and protect America’s water,

energy, mineral, biological, and land

resources. We help find the natural

resources needed to build tomorrow,

and supply the scientific understanding needed to help minimize or mitigate the effects of natural hazards

and environmental damage caused

by natural and human activities. The

results of our efforts touch the daily

 life of almost every American.

U.S. Geological Survey

Fact Sheet FS–043–96

Figure 4. Research Biologist Donna Shaver, aided by National Park Service personnel and beach 

visitors, investigate one of the first two confirmed returnees associated with an international, multiagency, experimental project to establish a secondary nesting colony of Kemp’s Ridley sea turtles at 

Padre Island National Seashore, May 1996. The only remaining nesting ground for this turtle is in 

Mexico. The turtles stay at sea about 12 years before returning to their nesting ground to reproduce. 

(Photograph by Carolyn Gorman, National Park Service.)