5.2.1 Regional Summaries

The South Central Texas Regional Water Plan includes water management strategies which emphasize water conservation and reuse and maximize use of available water rights and existing reservoirs. The Plan avoids development of large new reservoirs and minimizes depletion of water stored in aquifers. The Plan recognizes and includes several projects that are in various stages of implementation at this time, but are not yet complete. Additional strategies having significant support within the region, yet requiring further study regarding quantity of dependable water supply made available during severe drought, feasibility, and/or cost of implementation, are also included in the Plan. The water management strategies included in the South Central Texas Regional Water Plan are shown in Figure 5.2-1 and identified in Table 5.2-1 along with the associated new supply and presumed allocation to each county in the year 2050.

Water management strategies emphasizing conservation and reuse are expected to provide for about 21 percent of new supplies available in the year 2050 and include:

Municipal Demand Reduction (Conservation) (L-10 Mun.);

Irrigation Demand Reduction (Conservation) with Transfer (L-10 Irr.);

SAWS Recycled Water Program;

Aquifer Storage & Recovery (ASR) (SCTN-1a); and

Irrigation Demand Reduction (Conservation) (L-10 Irr.).

Water management strategies maximizing use of available water rights and resources and existing reservoirs are expected to provide for about 61 percent of new supplies available in the year 2050 and include:

Edwards Irrigation Transfers (L-15);

Canyon Reservoir – River Diversion (G-15C);

Canyon Reservoir – Wimberley, Woodcreek, & Blanco (G-24);

Lower Guadalupe River Diversions (SCTN-16);

New Colorado River Diversion (LCRA);[1]

Simsboro Aquifer (SCTN-3c);

Purchase Water from Major Provider (PMP); and

Desalination of Seawater (SCTN-17).

Water management strategies that simultaneously develop groundwater supplies and minimize depletion of storage in regional aquifers are expected to provide for about 11 percent of new supplies available in the year 2050 and include:

Edwards Recharge – Type 2 Projects (L-18a);

Carrizo Aquifer – Wilson & Gonzales (CZ-10C);

Carrizo Aquifer – Gonzales & Bastrop (CZ-10D); and

Carrizo Aquifer – Local Supply (SCTN-2a).

Projects recognized in the Plan that are presently being implemented are expected to provide for about 7 percent of new supplies available in the year 2050 and include:

Schertz-Seguin Water Supply Project (SSWSP);

Western Canyon Regional Water Supply Project (WCRWSP);

Hays/IH35 Water Supply Project (HIH35WSP)

Lake Dunlap WTP Expansion and Mid-Cities Water Transmission System (CRWA);

Carrizo Aquifer – Bexar & Guadalupe (BMWD);

Trinity Aquifer – Bexar (BMWD); and

Canyon Reservoir Contract Renewal (GBRA).

The Regional Water Plan includes several water management strategies that require further study and funding prior to implementation. Several of these strategies employ technologies that have been used previously, but further research is necessary to determine the cost of implementation, optimal scale and location, and quantity of dependable water supply that would be available in severe drought. These strategies are:

Brush Management (SCTN-4);

Weather Modification (SCTN-5);

Rainwater Harvesting (SCTN-9);

Additional Municipal Recycling (Reuse) Programs;

Small Aquifer Recharge Dams;

Edwards Aquifer Recharge & Recirculation Systems;

Cooperation with Corpus Christi for New Water Sources; and

Additional Storage (ASR and/or Surface).

Although specific quantities of new supply dependable in drought have not been determined for these strategies, it is understood that their implementation will contribute positively to storage and system management of many diverse strategies in the Regional Water Plan. The SCTRWPG recommends that State funding be made available to cooperatively support the refinement and implementation of these strategies.

The Regional Water Plan also includes the Edwards Aquifer Recharge and Recirculation Systems. The SCTRWPG recommends State and local funding for research at a level that would ensure consideration of this strategy in the next 5-year planning cycle. However, this management strategy may not be implemented unless the Plan is specifically amended to allow implementation.

Following publication of the Initially Prepared Plan (IPP) on August 17, 2000, the Regional Water Planning Group carefully reconsidered this strategy in light of its fundamental importance to many interests. The IPP included a footnote (IPP at pages ES-25 and 5-8) that indicated the strategy was included for research but not for implementation “unless the Plan is specifically amended to allow implementation.” The Planning Group has replaced that footnote with a discussion of its reasons for including the water management strategy for research and not for implementation.

Members of the SCTRWPG have expressed a wide range of views about this strategy. On the one hand, the Recharge and Recirculation System is viewed as experimental at best and dangerous at worst by several members of the RWPG. First, communities dependent on springflow from the Edwards formation to meet needs in the Guadalupe River Basin point to computer model runs showing potential aquifer drawdowns to levels far below its historic lows in the San Antonio area and the consequent potential for drying up the springs. The downstream Guadalupe River Basin interests state that they cannot accept a regional plan that jeopardizes this essential source of water. They want to see a clear demonstration that implementing Recharge and Recirculation will not damage the springs. Environmental groups wanting to protect endangered and threatened species at the springs also find the risk associated with what is regarded as an unproven technology to be unacceptable. They are also concerned about the potential damage to riparian and estuarine species and habitat if base flows are diverted during drought periods and/or flood flows are diverted during wetter periods. Utility managers, citing their requirements under Certificates of Convenience and Necessity to provide reliable supplies for municipal uses, are concerned that the lack of experience with this technology and the adverse results of computer model runs conducted by the Technical Consultant raise too many questions about the strategy for it to be recommended for implementation.

On the other hand, some members of the RWPG believe that the computer modeling done to date does not present an accurate picture of the system’s effects and capabilities. They believe the modeling is unfair in presenting results for a time period beginning with the drought of record, and they compare this to modeling the yield of a reservoir built early in the drought of record—there would be no yield for many years. (The Technical Consultant states that the modeling of this strategy was based on beginning conditions of a full aquifer and advise that substantial start-up time could be needed upon implementation in order for this strategy to provide additional dependable water supply during drought.) Others fear that implementation of some of the water management strategies included in the plan would preclude implementation of Recharge and Recirculation at a later time. They focus, in particular, on the need to include in the plan the strategy of Lake Dunlap diversions to the recharge area of the Edwards Aquifer. If the strategy of diverting water from the Guadalupe River at the Saltwater Barrier is implemented first, they fear that the Dunlap diversions would be impossible. That would mean that a major component of Recharge and Recirculation System would be precluded, damaging the chances of ever implementing this strategy.

All these interests nevertheless agree that the Recharge and Recirculation strategy may hold great promise and that optimizing use of the Edwards Aquifer is a cornerstone of water policy for the Water User Groups dependent on this underground source. They all support inclusion of this strategy in the Regional Water Plan for purposes of assuring continued research. They agree that implementation of the strategy would require an amendment of the Regional Water Plan. The amendment process can occur at any time after formal approval of the Regional Water Plan and requires a public hearing after a 30-day notice period.

The members of the South Central Texas Regional Water Planning Group have further agreed that the Recharge and Recirculation strategy must move as expeditiously as possible through the necessary phases of research to resolve uncertainties about how it could work in practice. To this end, the Planning Group members agree to support the accelerated research effort in the manner appropriate to each, whether by providing funding, reviewing research findings, offering in-kind services or other means. The goal of this effort will be to conclude the research as soon as practicable, possibly within a 3-year period and in any case in time for reviewing results for possible inclusion of this strategy in the next planning cycle. In this way, the Regional Water Planning Group intends to maintain its consensus approach to planning with careful regard to all interests it represents across the South Central Texas Region.

The Lockhart Reservoir is recommended as a potential reservoir site. Although the Regional Plan recommends other means of meeting projected water needs in Caldwell County, the SCTRWPG recognizes the strong interest of the local government in shifting from low-quality groundwater sources to a surface water supply system. The reservoir is considered by the local government to be an important economic development project to create new growth opportunities for the area. There are questions about economic feasibility at present, but the SCTRWPG recognizes the efforts in Caldwell County and by the Guadalupe Blanco River Authority to find a viable strategy to move the project forward. When that strategy is ready, the SCTRWPG will review the Lockhart Reservoir water supply option as a possible amendment to the Regional Water Plan.

The majority of the projected water supply needs or shortages in the South Central Texas Region are associated with municipal, industrial, steam-electric, and mining uses. Figure 5.2-2

summarizes these projected needs and illustrates the phased implementation of water management strategies necessary to ensure that these needs are satisfied. Clearly, implementation of a number of water management strategies on an expedited basis will be necessary to avoid significant hardship, water rationing, and/or cessation of discharge from Comal Springs in the event of severe drought during the next decade. Implementation of the South Central Texas Regional Water Plan could result in the development of more than 700,000 acft/yr of new water supplies that will be reliable in the event of a repeat of the most severe drought on record.

Substantial water supply needs or shortages are also projected for irrigation use in the South Central Texas Region. The Regional Water Planning Group has determined that it is not economically feasible to meet projected irrigation needs at this time since the net farm income to pay for water is less than the costs of water at the potential sources (Section 6). However, installation of Low Energy Precision Application (LEPA) equipment in six counties
(Table 5.2-1) is recommended as part of the Irrigation Demand Reduction (Conservation) (L-10 Irr.) water supply strategy included in the Plan. During the next planning cycle, the RWPG intends to examine agricultural needs throughout the region and to undertake additional socio-economic studies of Regional Water Plan impacts on agricultural resources. It will also review water management strategies that may meet irrigation needs during the planning period of
2005–2055.

Costs associated with the implementation and long-term operations and maintenance of water management strategies have been estimated in accordance with Texas Water Development Board rules and general guidelines. Projected annual and unit costs for the South Central Texas Regional Water Plan are summarized by decade in Figures 5.2-3 and 5.2-4, respectively. Annual costs (in 1999 dollars) are estimated to range from a low of about $120,000,000 in the immediate future, as some of the least costly water management strategies are developed, to a high of about $420,000,000 in 2040, at which time Desalination of Seawater (SCTN-17) is projected to be implemented. Estimated unit costs for the development of new supplies range from a low of $530 per acft to a high of $737 per acft and average $617 per acft or $1.89 per 1,000 gallons over the 50-year planning horizon. Unit costs tend to decrease beyond 2030 as the 30-year debt service period is completed for the many strategies to be implemented on an expedited basis. Cost estimates reflect regional water treatment capacity and balancing storage facilities sufficient to meet peak daily and seasonal water demands in the larger urban areas. Note also that no costs have been included for those projects in the Plan that are presently being implemented. Specific cost estimating procedures used in the technical evaluation of water management strategies for the South Central Texas Region are summarized in Appendix A of Volume III.

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[1] On December 14, 2000, late in the planning cycle, additional analysis by Region K of the Colorado River Diversion option with the full application of consensus environmental flow criteria indicated the yield of the project could be reduced by 19,000 acft/yr, resulting in an estimated 131,000 acft/yr of water available for transfer to Region L (Bexar and Hays Counties). The SCTRWPG acknowledges the different yield amounts for this project contained in Region L and Region K, and acknowledges that the yield of this project may be reduced to 131,000 acft/yr, and that the unit cost would be increased somewhat. This change could affect supplies to Hays County and Bexar County, and may necessitate supplying Hays County needs from other sources. However, due to this information being discovered late in the planning cycle, the SCTRWPG decided to retain the project in the Region L Plan with a yield of 150,000 acft/yr; however, this discrepancy between the two regional plans will be addressed early in the next planning cycle. There are adequate “contingency” supplies available within the Region L Plan to compensate for the proposed reduction in yield of the project.