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The Trans-Texas Water Program (TTWP) is a comprehensive integrated water resources planning process that is designed to identify the most cost-effective and environmentally acceptable methods for meeting future water needs in a large portion of Texas encompassing approximately one-third of the state’s population.

The TTWP represents a new approach to water resources planning and management in Texas. For the first time, water resources planning is being conducted through a partnership of state, regional, local, and federal resource agencies in collaboration with an array of potentially affected stakeholders. An extensive menu of options are being studied with an underlying objective being to optimize the use of existing water supplies and delay the need for new source development. Also, rather than being considered as an afterthought, environmental water needs and potential environmental impacts are at the forefront of the planning process.

The TTWP is also a flexible planning process in that it was designed to proceed in phases such that as information becomes available it can be used to refine or adjust the scope-of-work.

Preliminary Findings

One of the early decisions of the statewide Trans-Texas Policy Management Committee (PMC) was that current Texas Water Development Board (TWDB) water demand projections would be used as the baseline for planning in each study area. At the time Phase I studies were initiated TWDB’s most recent demand projections were those developed for the 1992 update of the State Water Plan. The Trans-Texas PMC adopted the demand scenario known as the "high-case with conservation" as the baseline projection, which was also used as the accepted scenario in the State Water Plan. The planning horizon selected by the PMC was the year 2050.

A key task in Phase I for the TTWP Southeast Study Area was to analyze projected water demands relative to available ground and surface water supplies in the 32 counties included in the study area. The results of this analysis, which were published in the Phase I Report, indicated that, taken as a whole, water demands within the Southeast Study Area would reach nearly 4.7 million acre-feet per year (4,195.89 million gallons per day) by the year 2050. Of this amount, roughly 3.3 million acre-feet per year (2,946.05 MGD) or 70 percent of the Southeast Area total was projected to be needed in the eight-county Houston Standard Metropolitan Statistical Area (SMSA). In consideration of presently available water supplies, it was estimated that the Houston SMSA would require supplemental water supplies from new Houston area sources or from outside the immediate area by the year 2020.

Concurrent with TTWP Phase I studies, TWDB, Texas Natural Resource Conservation Commission (now the Texas Commission on Environmental Quality), and Texas Parks & Wildlife Department  were engaged in a cooperative water planning process commonly referred to as "consensus state water planning". The overall goal of this process was to develop a new State Water Plan which would be accepted and supported by each agency. A key element of this consensus water planning process was the development of a new "most likely" water demand forecast that would serve as the baseline planning scenario for the new State Water Plan. New "consensus" demand projections were adopted by TWDB in January, 1995.

At meetings in March, 1994 and February, 1995, the Trans-Texas PMC adopted the policy that the new "consensus" demand projections would be used in the TTWP once they became available. As a consequence, one task in the Phase II scope- of-work for the Southeast Study Area was to update and reevaluate study area water demand projections and timelines for acquisition of supplementary water supplies. In July 1995, TTWP consultants released a technical memorandum report with this updated planning information. The results have been reviewed and accepted by the Southeast Area PMC and the Southeast Area Technical Advisory Committee and show projected water demands in 2050 for the 32-county study area to be roughly 900,000 acre-feet per year (803.47 MGD) less than the Phase I forecast. In particular, projected water demands for the Houston and Galveston metropolitan areas are 500,000 acre-feet per year (446.37 MGD) less than previously projected.

With significantly lower projected water demands for the Houston SMSA it now appears that available Houston area water supplies will be sufficient until approximately the year 2040. In addition, it can be expected that several water management options included in Phase II Studies will prove to be cost-effective in the near and mid-term and will further extend the time at which supplemental water sources will be needed for this area. These water management options include enhanced conservation, wastewater reuse, systems operations of existing reservoirs, and potential contractual water transfers from the Brazos and Trinity Basins.


The transfer of surplus "state" waters from basins having surplus supplies has long been considered as a viable means of supplying areas experiencing water shortages. Each of the last three State Water Plans have identified the Toledo Bend Reservoir as critical for meeting future water needs in all of the Southeast Texas Study Area. The key question has been the timing of the need for supplemental water to be supplied through interbasin transfers.

The results of the conceptual planning accomplished in Phase I for the TTWP Southeast Area indicated a mid and long-term need for additional supplies in the greater Houston area and identified the transfer of surplus state water from the Toledo Bend Reservoir as an alternative worthy of further study. Consequently, a major element of the Phase II scope-of-work was to evaluate in greater detail the costs, environmental impacts, and legal/institutional issues associated with such a water transfer. In addition to studying potential impacts of large scale diversions to the ecology of the Sabine River and Sabine Lake, the Phase II scope included an evaluation of several alternative routes for conveying water from the Sabine River to the greater Houston area.

Based on findings regarding the timing of the need for supplemental water supplies for the Houston area the Southeast Area PMC has revised the Phase II scope- of-work for tasks relating to transfers of surplus state waters from the Sabine Basin to include only conceptual planning and to issue a summary report of these findings.

Funding for the Phase II study of the transfer of surplus state waters from the Sabine Basin to the Houston area is being redirected to environmental studies to improve the current state of knowledge about the Sabine Lake estuary system and to increase public input and coordination concerning this important ecosystem. A Technical Advisory Team has been formed to plan for a Sabine Lake Conference scheduled for September 13 & 14, 1996 in the Golden Triangle Area. The Technical Advisory Team is composed of a broad based group of people from Texas and Louisiana. Also, Lamar University  is involved in the studies being conducted in the Sabine Lake Estuary.

Another cornerstone in the Trans-Texas Water Program is that one area of the State will not be hurt to help another area of the State. The primary responsibility of the SRA in the TTWP is to protect Sabine Basin water resources for future use in the Sabine Basin and, if there are future interbasin transfers, to insure that the basin of origin is protected. In order to accomplish this a Water Equity Committee of 24 local leaders has been appointed by the South East Texas Regional Planning Commission to assist with determining the various equity issues involved in interbasin transfers (i.e. - how do we make it fair to all concerned?). At the same time, we recognize that many areas of the State may experience water shortages which will get worse in future years if nothing is done to provide workable solutions. The Trans-Texas Water Program is our opportunity to have input into resolving regional water issues in an acceptable manner and minimizing the possibility of major political battles in future years.

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