U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 045-99

April 1999

Texas

Online Assessment of Hydrologic

Conditions

In 1997, the Texas Legislature

passed a comprehensive revision to

the Texas Water Code. This legislation (Senate Bill 1) changed water

planning in Texas from a statewide

to a regional activity. By September

2001, the 16 regions created by

Senate Bill 1 must produce water

plans to address their water needs

during drought-of-record conditions,

and must identify water-management

strategies for periods when streamflows, reservoir storage, and groundwater levels are 50 and 75 percent of

normal.

A key aspect of the mandated

planning is assessment of current

and near-realtime hydrologic conditions. The USGS, in cooperation

with the Texas Water Development

Board, has begun a project to

develop and maintain maps and

tables on the Internet that present

comparative and descriptive assessments of current streamflows,

reservoir storage, and ground-water

levels for climatic regions, hydrologic regions, and river basins of

Texas.

The statewide assessment network

currently comprises 30 streamflow

stations, and ultimately will comprise 50 streamflow stations, 124

reservoirs, and 40 wells. Online

State maps show network stations

linked to tables of current and the

past 7- and 30-day streamflows,

percentages of time that current

values are exceeded, and other

station-specific information (fig. 1).

The hydrologic assessment for

Texas can be accessed through the

USGS Texas home page at http://

tx.usgs.gov/.

Near-Realtime Water-Quality

Monitoring

The U.S. Environmental Protection

Agency (EPA) initiated the Environmental Monitoring for Public Access

and Community Tracking (EMPACT)

Program in 1998. The goal of

EMPACT is to provide public access

to accurate, clearly communicated,

timely environmental monitoring

data—physical, chemical, and

biological information intended to

give insight into environmental

conditions—in 75 major metropolitan

areas of the country.

The USGS, in cooperation with the

EPA, initiated a pilot EMPACT

project in 1998 to monitor and report

on the water quality at three sites on

Buffalo Bayou, a primary stream in

the Houston metropolitan area and

tributary to the Houston Ship Channel. All data collected are to be

presented on the Internet through the

EPA home page. Monitored waterquality properties are to be provided

on a near-realtime basis in graphical

and tabular displays that include

explanatory information, descriptive

statistics, and applicable State standards for the selected properties.

Partnerships Generate New Map

Products

The Texas Strategic Mapping Initiative (StratMap) is a multiyear initiative among the State of Texas, the

USGS, and local partners to develop

current digital data layers for Texas.

The data layers include digital

orthophoto quadrangles (DOQ) (fig.

2), digital elevation models (DEM)

(fig. 3), high-resolution water features, topographic contours, transportation, boundary, and soil surveys. A

DOQ is a digital image of an aerial

photograph that combines the image

characteristics of a photograph with

the geometric qualities of a map. The

DOQ’s, created from 1995 to 1997

color-infrared photographs, are the

DAILY STREAMFLOW

ASSESSMENT FOR TEXAS

BY CLIMATIC REGION

ASSESSED APR 20, 1999

Streamflow-gaging station showing the

percentage of time the mean flow for the

previous 1 day was equaled or exceeded,

on the basis of long-term station data

0 — 5 percent (very high flow)

5 — 30 percent (high flow)

30 — 70 percent (normal flow)

70 — 95 percent (low flow)

95 — 100 percent (very low flow)

Station currently unavailable

Click on streamflow-gaging

station or climatic region

for more information

High

 Plains Low Rolling Plains

North

Central

East

Texas

Trans - Pecos Edwards

Plateau

South

Central

Southern

Lower

Valley

Upper

Coast

Figure 1. One of several maps

available on the Internet that shows,

by color code, the percentage of time

that mean flow for the previous day at

network stations has been equaled or

exceeded.
science for a changing world

foundation for developing the other

data layers. A seamless DEM of the

entire State will be used to delineate

small watersheds; this information is

essential for water management and

protection. The high-resolution hydrography will be integrated into the

National Hydrography Dataset, a welldocumented, maintainable, and

nationally consistent dataset for hydrologic modeling that the USGS and

the EPA are cooperatively developing.

StratMap is a model approach to

encouraging cooperation with private,

local, State, and Federal agencies to

create a spatial data framework that is

too costly for any single entity to

finance. Appropriations in Texas

Senate Bill 1 provided initial funding

for StratMap. The USGS has established a Texas mapping liaison office

in Austin to help support this cooperative effort.

Coal and Oil and Gas Resources

The assessment of Texas Gulf Coastal

Plain coal deposits is part of the

USGS National Coal Resource

Assessment, a multiyear project to

identify and characterize coal beds

and coal zones that will provide the

bulk of the Nation’s coal-derived

energy during the first quarter of the

21st century. Texas ranks sixth among

the States in U.S. coal production.

Most of the coal mined in Texas is

used as fuel for electric powergenerating plants. In Texas, the USGS

is working with the Bureau of Economic Geology, the Railroad Commission, and mining companies to

provide high-quality, digital, georeferenced databases and geologic

interpretations characterizing the coal

that is expected to be mined during

the next 30 years in several priority

areas. Geologic studies are underway

to improve understanding of the

stratigraphy of the coal-bearing beds.

Emphasis is being given to characterization of coal geochemistry, including the environmentally sensitive

trace elements identified by the U.S.

Clean Air Act Amendments of 1990.

The USGS also is conducting a

National Oil and Gas Assessment to

understand the geologic reasons for,

and assess the availability of, oil and

gas resources in the United States. In

1995, the Assessment determined that

the Austin Chalk in Texas and Louisiana is the Nation’s largest onshore

domestic continuous-type, unconventional oil resource. “Unconventional”

refers to a broad class of hydrocarbon

deposits that cannot be developed by

traditional methods. Recent exploration and production in the Austin

Chalk has shown that the unit has

additional potential as a continuoustype deep-gas resource. In 1997, an

Austin Chalk well in Washington

County, Tex., set an initial gas-flowrate record for horizontal wells in the

United States of 84.7 million cubic

feet per day.

USGS scientists are studying the

stratigraphy and the burial and

production histories of the Austin

Chalk to determine a reasonable

quantitative estimate of this large

domestic oil and gas resource.

Through such studies, scientists

improve their understanding of the

generation, distribution, accumulation, availability, and recoverability

of oil and gas. For example, data and

Figure 3. Digital elevation model

(DEM) of the Big Bend area near

Lajitas, Tex., looking southeast across

the Rio Grande. This DEM has been

combined with an infrared Landsat

satellite image, which accounts for

the false color. Red indicates

vegetation.

Figure 4. General chemical

composition of samples from the

Austin Chalk from an oil well, Giddings

field, Tex. The producing zone in this

well is in the lower part of the Austin

Chalk, where nonchalk material

content is near or less than 10

percent, and brittle chalk rock content

is most abundant.

0 10 20 30 40 50 60 70 80 90 100

PERCENTAGE (BY WEIGHT) OF NONCHALK

MATERIAL AND CHALK ROCK IN BULK ROCK

DEPTH BELOW LAND SURFACE, IN FEET 7500

7550

7600

7650

7700

7750

7850

7900

7800

7950

8000

8050

8100

L zone

K zone

J zone

I zone

H zone

G zone

F zone

E zone

D zone

C zone

B zone

A zone

INFORMAL ZONES

Eagle Ford Shale

Base of

Austin

Chalk

Producing zone

Ash bed

Nonchalk Chalk

Figure 2. Digital orthophoto quadrangle (DOQ) of Brownsville, Tex.-

Matamoros, Tamaulipas, area.
Texas

relations between composition and

production demonstrate that productive intervals commonly have the

lowest nonchalk material content and

are the most “brittle” zones of the

Austin Chalk (fig. 4). Knowledge of

the distribution of the Austin Chalk

assists scientists in outlining geographic extent, maturity, and economics, among other factors, needed to

identify current and future exploration areas.

United States-Mexico

Border Activities

The United States and Mexico share

concern about many environmental

issues within the 2,000-mile border

region that comprises parts of four

U.S. and six Mexican States. The

USGS is involved in many initiatives

to provide relevant scientific information for this region of diverse physical

settings and habitats.

Mapping

Current, accurate, binationally

compatible geographic and spatial

data are required to develop appropriate and effective ways to address

environmental issues. The USGS in

Texas is working with Federal, State,

and local agencies and other organizations in the United States and

Mexico to develop digital map data

for the 100-mile zone on each side of

the border. From 1996 color-infrared

aerial photographs of the zone on the

U.S. side of the border, the USGS is

completing DOQ’s to be used to

revise maps and databases necessary

for environmentally related projects.

High-resolution land-use and landcover data from the DOQ’s are being

used in a cooperative USGS-Texas

Natural Resource Conservation Commission (TNRCC) project to determine the relative contributions of

contaminants from various areas to

Arroyo Colorado, a stream near the

mouth of the Rio Grande. The landuse data will be used in a watershed

model developed by the USGS and

applied by the TNRCC to obtain total

maximum daily load allocations for

selected contaminants in Arroyo

Colorado.

The U.S. Department of the Interior

High-Priority Digital Data Program

has allowed the USGS, in partnership

with private industry, to complete

DEM’s, digital raster graphs (DRG),

and public land-survey system (where

applicable) and boundary digital line

graphs (DLG) for the entire U.S. part

of the border region. A DRG is a

scanned image of a USGS topographic map that can be used as a

base to register, collect, and interpret

other data. A DLG is a digital representation of areas, lines, and points

composed of specific data.

Additional information about U.S.-

Mexico border mapping is on the

Internet at http://rmmcweb.cr.usgs.

gov/public/usm/index.html.

Habitat Degradation and Fish and

Wildlife Health

The Rio Grande Basin, which includes Big Bend National Park and

the Lower Rio Grande Valley National Wildlife Refuge System, is a

diverse and sensitive ecosystem. A

multiphase binational toxic-substances study has shown some

evidence of degraded water quality

and habitat; however, little is understood about the specific sources of

contaminants and the ecological

effects of expanding industrial

development and population growth.

USGS scientists are studying selected

reaches of the lower Rio Grande,

focusing on the relations between

habitat degradation and the health of

fish and wildlife communities dependent upon the river system (figs. 5

and 6). The USGS is conducting its

work in collaboration with established binational partners in the

border region—the U.S. Fish and

Wildlife Service, Bureau of Reclamation, National Park Service, TNRCC,

Texas Parks and Wildlife Department

(TPWD); and counterparts in Mexico,

which include the Commission for

the Understanding and Use of Biological Diversity and the Secretariat

for Environment, Natural Resources

and Fisheries.

Water-Quality Monitoring

The USGS has monitored water quality in the Rio Grande Basin as a part

Figure 5. Blue Sucker with skin lesions

found in the lower Rio Grande during

an aquatic-contaminant investigation

to assess the biological significance

of degraded water quality.

Figure 6. Blood and hair analyses for

organic and heavy metal contaminants are part of a long-term ocelot

population monitoring program on

Laguna Atascosa National Wildlife

Refuge, south of San Antonio.

(Photograph by Linda Laack, U.S. Fish and

Wildlife Service.)
Printed on recycled paper

USGS office locations USGS State Representative

8027 Exchange Drive

Austin, TX 78754-4733

(512) 927-3500

FAX (512) 927-3590

USGS Home Page:

http://www.usgs.gov

Reports and products:

1-888-ASK-USGS

The USGS has 180

employees in Texas

Angleton

College Austin Station

Nacogdoches

Corpus Christi

Padre Island

Fort Worth

Houston

Lubbock

San Angelo

San

Antonio

Wichita 

Falls

M E X I C O

of the USGS National Stream Quality

Accounting Network (NASQAN)

since 1995. NASQAN is designed to

characterize the concentrations and

transport of sediment and selected

chemical constituents in the Nation’s

large rivers. NASQAN sampling at

eight sites in the Rio Grande Basin in

Texas is providing information needed to identify regional sources of

various constituents, including agricultural chemicals and trace elements.

Kemp’s Ridley Sea Turtle—

Increasing Odds For Survival

The Kemp’s ridley is the world’s

most endangered sea turtle. The only

major nesting site for the sea turtle is

a beach near Rancho Nuevo in

Mexico. During the 1940’s, an

estimated 40,000 females nested on

this Mexican beach. The number of

nesting turtles dropped to the hundreds during the 1970’s. In 1978, to

help preserve the species, an international experimental project was

launched at Padre Island National

Seashore in Texas to establish a

secondary nesting colony. In recent

years, the discovery of Kemp’s ridley

turtle nests at Padre Island has

confirmed the success of the program.

USGS scientists are conducting

studies to document Kemp’s ridley

nesting and to protect, monitor, and

incubate eggs in an effort to sustain

the secondary breeding colony.

Additional studies are focused on

other species of sea turtles in the

Mansfield Channel along the southern

Texas coast.

Effects of Urbanization on Water

Quality of the Edwards Aquifer

Recharge Zone, San Antonio

The highly productive Edwards

aquifer is the sole source of water for

San Antonio, and is the major source

of water in south-central Texas. Most

recharge to the Edwards aquifer is

from direct infiltration of rainfall and

streamflow losses in the faulted and

fractured limestone outcrops of the

recharge zone. The permeable rocks

of the outcrop make the source water

for public supply susceptible to

contamination from spills or leakage

of hazardous materials and runoff

from rapidly developing urban areas

on and near the recharge zone.

The USGS is assessing the quantity

and quality of runoff and the quality

of shallow ground water to learn

more about the relations between

residential and commercial land use

and the quality of Edwards aquifer

water in and near the recharge zone

(fig. 7). Information to define current

conditions and to assess potential

land-use impacts is being developed

through cooperative surface-water

projects with the San Antonio Water

System and ground-water projects

supported by the USGS and the

Edwards Aquifer Authority.

New Wastewater Treatment

Decreases the Environmental

Impact of Animal Feedlots

Working with the EPA, U.S. Department of Energy, Texas State Soil and

Water Conservation Board, TPWD,

and animal feedlot operators, the

USGS has developed a treatment for

wastewater from feedlots that makes

the water suitable for reuse using

constructed wetlands. Water and

manure are collected from 1,000 head

of cattle and 280 sows at the Texas

Tech University Animal Science

Facility in New Deal. The water and

manure are directed through a series of

ponds to allow settling of waste,

removal of nutrients by aquatic plants,

and removal of organic material by

aquatic organisms. The treated water

ultimately is diverted into a playa lake.

This integrated treatment of feedlot

wastewater demonstrates conversion

of livestock wastes by microorganisms, aquatic plants, and animals

including sulfur-reducing bacteria,

microalgae, duckweed, and fish. The

process also involves diverting some

of the waste to an anaerobic pit

designed for recovery of methane gas

that is used on-site for producing

steam and electrical energy.

Figure 7. USGS personnel lower a

pump for water sampling into an

Edwards aquifer recharge zone

monitoring well in San Antonio.