You are here: Home → Permitting → Water Rights and Availability → Water Availability Models

Water Availability Models

Maps of water availability in the river basins of Texas. Water availability model and river basin input files. Executable files for running the water availability models.

Background

Water Availability by River Basin

WRAP: The Modeling Program

Input Files by River Basin

Background

What is a water availability model?

A water availability model is a computer-based simulation predicting the amount of water that would be in a river or stream under a specified set of conditions.

The model of a specific river basin consists of two parts:

  • the modeling program, called "WRAP", short for Water Rights Analysis Package
  • a text file that contains basin-specific information for WRAP to process (these text files are called input files)
Back to Top

How are these models used?

Water Availability Models are used to determine whether water would be available for a newly requested water right or amendment.

TCEQ staff uses two models in evaluating applications:

  • the Full Authorizaton simulation, in which all water rights utilize their maximum authorized amounts, is used to evaluate applications for perpetual water rights and amendments.
  • the Current Conditions simulation, which includes return flows, is used to evaluate applications for term water rights and amendments.

If water is available, these models estimate how often the applicant could count on water under various conditions. For example, would water be available only one month out of the year, half the year, or all year? And would that water be available in a repeat of the drought of record?

In evaluating applications for a new appropriation of water and some applications for amendments to existing water rights, TCEQ staff must consider recommended environmental flow needs. Environmental flow needs include instream flows and freshwater inflows to bays and estuaries.

The water availability models provide information that assists TCEQ staff in determining whether to recommend the granting or denial of an application.

Back to Top

Water Availability by River Basin

What are general water availability maps?

These maps are generated from WAM output for both of the permitting runs (Full Authorization and Current Conditions) for each basin. The maps generally indicate the percentage of months during the period of record that unappropriated water is available at various locations in each basin.

Back to Top

How are general water availability maps used?

The water availability maps can be used as a general indicator to see if water would be available with sufficient frequency to consider submitting a new application or an amendment to an existing water right. The availability of storage, the total amount requested, the type of use, environmental flow needs and other factors could affect the availability of unappropriated water for a particular project.

In using these maps, please keep these points in mind:

  • The maps do not show how much water is present at any given point. If the river is always full but every drop is appropriated, the map will be red, showing that no water is available.
  • The maps do not show how much water is available. They show only how often some water is available.
  • Each map is valid as of the date shown on the map. New water rights or amendments to existing water rights may have been approved since the maps were created.
  • The State Wide Availability Maps provides a very general look at water availability for the entire state. To look at water availability in a specific basin, use the main specific maps.
Back to Top

General Water Availability Maps by River Basin

Of the twenty three river basins in Texas, maps are available for the following:

Other maps will be posted here as they become available.

Back to Top

Canadian River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Red River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Sulphur River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Cypress River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Sabine River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Neches River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Neches-Trinity Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Trinity River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Trinity-San Jacinto Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

San Jacinto River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions

San Jacinto-Brazos Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Brazos River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Full Authorization

Current Conditions
Current Conditions
Back to List of Maps

Colorado River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions

Colorado-Lavaca Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions

Lavaca River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions

Lavaca-Guadalupe Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions

Guadalupe River Basin

Click on Images to see full-size maps

Full Authorization
Current Conditions

San Antonio River Basin

Click on Images to see full-size maps

Full Authorization
Current Conditions

San Antonio-Nueces Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Nueces River Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

Nueces-Rio Grande Coastal Basin Availability Maps

Click on Images to see full-size maps

Full Authorization
Current Conditions
Back to List of Maps

WRAP: The Modeling Program

All river basin models are compatible with the March 2003 version of WRAP. The TX-WRAP, Tables, and WinWRAP files are compressed in executable (.EXE) format (Help with Downloading Files.)

Back to Top

Input Files by River Basin

Data files necessary to run the water availability model for the following river basins are available as compressed files in "ZIP" format (Help with Downloading Files.)

Data for the TCEQ permitting runs (Full Authorization and Current Conditions) is available. In addition to the basin specific files needed to run the models, a text file is included in the ZIP file for each permitting run that details recent changes to the input files.

If you need more information, please contact: The Water Rights Permitting & Surface Water Availability Team at 512/239-4691 or send an email to: wras@tceq.texas.gov

It should be noted that the basin input files are dated and the information can change as new and amended water rights are added to the models.

Back to Top

Canadian River Basin

Back to List of River Basins

Red River Basin

Back to List of River Basins

Sulphur River Basin

Back to List of River Basins

Cypress River Basin

Back to List of River Basins

Sabine River Basin

Back to List of River Basins

Neches River Basin

Back to List of River Basins

Neches-Trinity Coastal Basin

Back to List of River Basins

Trinity River Basin

Back to List of River Basins

Trinity-San Jacinto Coastal Basin

Back to List of River Basins

San Jacinto River Basin

Back to List of River Basins

Brazos River Basin and San Jacinto-Brazos Coastal Basin

Back to List of River Basins

Colorado River Basin and Brazos-Colorado Coastal Basin

Back to List of River Basins

Colorado-Lavaca Coastal Basin

Back to List of River Basins

Lavaca River Basin

Back to List of River Basins

Lavaca-Guadalupe Coastal Basin

Back to List of River Basins

Guadalupe River Basin and San Antonio River Basin

Back to List of River Basins

San Antonio-Nueces Coastal Basin

Back to List of River Basins

Nueces River Basin

Back to List of River Basins

Nueces-Rio Grande Coastal Basin

Rio Grande Basin

Back to List of River Basins
Related content
Document Actions
Last Modified Fri, 29 Jul 2011
©2002-2012 Texas Commission on Environmental Quality