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Water Availability Models

Information about the Water Availability Model (WAM) and the Water Rights Analysis Package (WRAP). Explanation of various river basin input and GIS files. WRAP input files for running the water availability models.

HOT The Sunset Advisory Commission directed TCEQ to create a report on the status of its water availability models (WAMs), including the development and structure of WAMs, information on ongoing WAM updates, prioritization for other WAM dataset updates, and estimated cost for the prioritized updates. (Recommendation 3.3).

Water Availability Model Status Report

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 used by TCEQ consists of two parts:

  • the modeling program, "WRAP"(Water Rights Analysis Package)
  • text files that contain basin-specific information for WRAP to process (input file or WAM)
WAM Resolved Technical Issues

How are these models used?

TCEQ staff use the models in evaluating water rights applications to help determine if water would be available for a newly requested water right or amendment, or if an amendment might affect other water rights.

  • Full Authorization simulation model:
    • all water rights utilize their maximum authorized amounts
    • used to evaluate applications for perpetual water rights and amendments
  • Current Conditions simulation model:
    • includes return flows and current water use
    • used to evaluate applications for term water rights

If water is available, these models estimate how often water would be available. For example, would it be available only during very wet times, or would it also be available during very dry times?

Applicants may also use the models when preparing to apply for a new water right or an amendment.

WRAP: The Modeling Program

The WRAP modeling system includes computer programs for processing basin input files for each river basin in Texas. Texas A&M University maintains these programs, executables, and manuals.

Input files for the model

  • New permanent water rights or amendments
    • Full Authorization data set: This model shows the amount of water that would remain available for appropriation if all currently permitted perpetual water rights holders withdrew their full authorized amount of water.
  • New term water rights
    • Current Conditions data set: This model shows the amount of water that would remain available for appropriation if all permitted water rights holders withdrew the amount of water they are now using. Includes return flows.

What do I get with the files?

  • Full Authorization (Run 3) or Current Conditions (Run 8) data sets include:
    • *.dat, *.dis, *.eva, *.fad, *.flo, *.txt files and others as applicable.
    • Note: Not all basins include all of these files. TCEQ does not maintain the current conditions WAM in basins where water rights use most or all of their authorized water. Information on water use is now available through the Texas Water Rights Viewer.
  • GIS files and information on the location of water rights points and reservoirs is now available through the Texas Water Rights Viewer.

    WRAP Input files by River Basin

    The agency standard used for zipping files is the freeware 7ZIP. If you experience difficulties downloading and extracting data from our site, please try the following:1) download the 7ZIP software from the web and use it to extract the data; and/or 2) contact your IT department and confirm that there are no limitations for downloading the files. The file extensions inside the zip files may be blocked by your firewall. If you still cannot download the data, please contact us at

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