Model changes management of Texas surface waters
In an office on the second floor of a Texas A&M University building, on a desktop computer operating with the popular Microsoft Windows, Dr. Ralph Wurbs has designed a computer modeling system that has changed the way Texas manages its rivers, streams and reservoirs.
The modeling system called Water Rights Availability Package, or WRAP for short, is a set of computer programs developed by Wurbs, a professor of civil engineering, and his graduate students that simulates management of the water resources of river basins. The model helps determine how much and at what level of reliability water will be available for environmental and human needs.
The Texas Commission on Environmental Quality (TCEQ) uses WRAP in its Texas Water Availability Modeling (WAM) system to evaluate and approve surface water right permits in Texas. Any water resources development project or water use action involving the streams and lakes of the state requires either a new permit or modification of an existing permit. The WRAP/WAM modeling system determines whether sufficient water is available for a proposed new or expanded water use and assesses the impacts on all the other water uses in the river basin.
Currently, the state has about 8,000 active water right permits.
TCEQ requires that permit applicants and their consultants use the WRAP/WAM system in preparing their applications.
“Discussion of pertinent issues is significantly enhanced by both the water right permit applicant and regulatory agency staff using the same modeling system,”Wurbs said.
TCEQ and its partner agencies—Texas Water Development Board and Texas Parks and Wildlife Department—and consulting firms developed the WAM system after the Texas Legislature enacted Senate Bill 1 in 1997, following the drought of 1996.
In addition to the generalized WRAP simulation model, the WAM system has specific information (or datasets) for all 23 river basins in the state.
Ten consulting engineering firms, under contract with TCEQ during 1997–2003, developed the individual datasets and simulated a set of alternative wateruse scenarios. The Center for Research in Water Resources at the University of Texas provided geographic information system (GIS) support for developing the datasets. During the same time Wurbs and his graduate students, working under a contract between the commission and the Texas Water Resources Institute, expanded WRAP methodologies and software from earlier versions.
The state currently has active permits for about 3,500 reservoirs, thousands of water supply diversions, several hydroelectric plants and numerous environmental instream flow requirements. Each of these active permits is included in the datasets.
Besides the commission using the WAM/WRAP modeling system in water rights permiting, the Texas Water Development Board and its 16 regional planning groups use the modeling system for developing its water plans, which were also mandated by Senate bill 1. TCEQ’s approval of water right permit applications requires that proposed actions be consistent with relevant regional plans.
River authorities, water districts and other water management organizations are beginning to use the WRAP model in operational planning studies to optimize operations of their facilities and available water resources,Wurbs said.
“The Texas experience has also generated interest in similar applications of WRAP in other states and countries,” he said, including a project in Armenia by one of his graduate students.
Twenty years of refining
The WRAP modeling program and its widespread use did not get where it is overnight. Dr. Ralph Wurbs and his stream of graduate students have tweaked and fine-tuned WRAP for 20 years.
The original WRAP, initially called TAMUWRAP, stemmed from a 1986–1988 research project at Texas A&M University titled, Optimizing Reservoir Operations in Texas, sponsored by the federal/state Cooperative Research Program administered by the U.S. Geological Survey and Texas Water Resources Institute. The Brazos River Authority served as the nonfederal sponsor.
Some of the newest changes to WRAP, developed during 2002–2005 and documented in TWRI’s Technical Report 284 released in January 2006, include:
- Capabilities for short-term reliability analyses based on current storage conditions (Or what is the likelihood of meeting water needs in the near future knowing storage conditions today?)
- Flood control operations
- Salinity tracking motivated primarily by natural salt pollution problems in several Texas river basins
- Daily or other sub-monthly time steps
- Disaggregation of monthly naturalized flows to daily flows
- Flow forecasting
- Flow routing
- Calibration of routing parameters
Other recent updates to WRAP with significant enhancements can be found in the following publications:
- Water Rights Analysis Package Modeling System Reference Manual. TWRI Technical Report 255, Second Edition, April 2005.
- Water Rights Analysis Package Modeling System Users Manual. TWRI Technical Report 256, Second Edition, April 2005.
- Fundamentals of Water Availability Modeling with WRAP. TWRI Technical Report 283, April 2005. This report serves as an introductory tutorial to help new users apply the model quickly for basic water availability modeling applications.
- Comparative Evaluation of Generalized Reservoir/River System Models. TWRI Technical Report 282, April 2005. This report combines a broad coverage of reservoir/river system modeling in general with a focus on the SUPER, RiverWare, MODSIM, HEC-ResSim, and WRAP modeling systems.
These technical reports are available at http://twri.tamu.edu/reports.php.
The software and documentation are also available at http://ceprofs.tamu.edu/rwurbs/wrap.htm. The public domain WRAP software and documentation, along with input datasets for all the river basins of Texas and other WAM information, are available under the heading Water Availability Modeling at the TCEQ Web site: http://www.tceq.org.
Development and expansion of WRAP has been sponsored by:
- Texas Commission on Environmental Quality
- U.S. Army Corps of Engineers Fort Worth District.
- Texas Water Resources Institute
- U.S. Department of the Interior
- Texas Advanced Technology Program administered by the Higher Education Coordinating Board
