Section 5
Regional, County, City,
Water User Group, and Major Provider Plans

5.1       Regional Water Planning Process

The South Central Texas Regional Water Planning Group (SCTRWPG) has employed a planning process (Figure 5.1-1) focused on the development of a Regional Water Plan to meet the needs of every water user group in the region for a period of fifty years.  Given the history of sharp and divisive conflict concerning water planning in this region, the planning process has provided extraordinary opportunities for participation by water user groups in providing input to achieve the goal of a plan that will “provide for the orderly development, management, and conservation of water resources…” 31 TAC 357.5(a).  To build consensus among the constituencies represented by the members of the SCTRWPG, the planning process has emphasized the coordination and careful integration of technical information with information provided through public participation.   Figure 5.1-1.  Planning Process

Conflict over the past several decades in this region has focused on how to manage the Edwards Aquifer so as to meet the needs of many water user groups.  Central to progress in resolving this conflict, and thus in achieving the formulation of a water plan acceptable to all constituencies represented in the SCTRWPG, is the assurance that all of the different competing strategies for meeting water needs will be given consideration.  It has thus been central to the viability of the planning process itself that the evaluation of water supply options and combinations of these options in the context of a regional plan receive extraordinary attention.

To this end, the SCTRWPG has employed a planning process that ensures evaluation of virtually all the water supply options or management strategies that have been proposed or discussed in the past, together with several new ones that have never before been subjected to technical evaluation.  To achieve confidence by all constituencies in the planning process, it has been necessary to evaluate the options both on a stand-alone basis (Volume III—Technical Evaluations of Water Supply Options) and in various combinations in the context of alternative plans (Volume II—Technical Evaluations of Alternative Regional Water Plans).  Given the fact that some of the proposed strategies for regional management are at odds with one another, it has been important to look at a series of alternative regional water plans.  By formulating five alternative regional water plans, the SCTRWPG has carefully considered many diverse management strategies.  In keeping with logical and acceptable planning methods, the SCTRWPG has taken the best components of these alternative plans and developed a Regional Water Plan (Volume I – Executive Summary and Regional Water Plan).

5.1.1    Water Supply Options

The SCTRWPG completed the technical evaluation of some 61 water supply options identified for potential inclusion in alternative plans and ultimately the Regional Water Plan (see Volume III, Introduction for a description of procedures used to identify and evaluate water supply options).  These options can be generally categorized by source of water as follows:

·        Local/Conservation/Reuse/Exchange

·        Edwards Aquifer Recharge

·        River Diversions with Storage

·        Existing Reservoirs

·        Potential New Reservoirs

·        Carrizo and Other Aquifers

Table 5.1-1 summarizes key information regarding some 79 water supply options (including variations of the 61 originally identified for consideration) for which technical evaluations were completed.  In Table 5.1-1, the water supply options are categorized in accordance with the manner in which the water might be used within the context of a regional plan and ranked by unit cost of supply.  Additional summary information in Table 5.1-1 includes quantity of water, land impacted, time to implement, and qualitative measures of environmental sensitivity, public acceptability, and reliability.  Comprehensive documentation of the technical evaluation of these water supply options is included in Volume III.

5.1.2    Alternative Regional Water Plans

The SCTRWPG defined a Regional Water Management Alternative Plan (hereinafter referenced as an Alternative Regional Water Plan) as a combination of options and strategies that could meet the water needs of the entire South Central Texas Region.  The SCTRWPG formulated five alternative regional water plans using the water supply options in Table 5.1-1 (and others identified through public participation) and authorized technical evaluation of each plan.  Appendix B summarizes the procedures followed in the formulation of alternative regional water plans.  The five alternative regional water plans are identified as follows:

·        Planning Unit (PU) Alternative

·        Environmental/Conservation (EC) Alternative

·        Economic/Reliability/Environmental/Public Acceptance (EREPA) Alternative

·        Inter-Regional Cooperation (IRC) Alternative

·        Recharge & Recirculation (R&R) Alternative

Technical evaluations and comparisons of these five alternative regional water plans are summarized in Volume II.  Upon review and consideration of these five alternative plans, the SCTRWPG formulated the Regional Water Plan which is summarized at the regional, county, city, and water user group level in Section 5.2.  General procedures and assumptions for technical evaluation of the five alternative plans and the Regional Water Plan are enumerated in Appendix B.

In Volume III, the technical evaluations of the water supply options are presented as if each would be a stand-alone, individual management strategy.  These stand-alone options were often modified in the formulation of alternative regional water plans.  In many cases, only a portion of the potential water supply of an individual option was needed to satisfy the projected water needs of water users of the region.  In other cases, a similar option evaluated at one location on a stand-alone basis was included in an alternative regional water plan at another location.  Incorporating such modifications and refinements, the Regional Water Plan and the alternative regional water plans were individually evaluated using technical procedures and assumptions similar to those for the evaluations of water supply options.

In order to facilitate and expedite the technical evaluations of alternative regional water plans, the Guadalupe–San Antonio River Basin Water Availability Model (WAM)[1] and the Edwards Aquifer Model (GWSIM4)[2],[3] were enhanced and computationally linked.  Enhancements to GWSIM4 include program logic and data development for simulation of Critical Period Management Rules under development by the Edwards Aquifer Authority, Edwards Aquifer pumpage transfers from irrigation to municipal use, and the southern Bexar County aquifer storage and recovery program being developed by the San Antonio Water System.  Enhancements to the WAM include the addition of program logic to facilitate daily computations necessary for application of Consensus Environmental Water Needs Criteria (Appendix B, Volume III) in the simulation of new reservoirs and river diversions with storage.  In addition, GWSIM4 and the WAM may now be computationally linked so that options and alternative plans involving diversions of springflow and other streamflow to the outcrop of the Edwards Aquifer for recharge enhancement and increased pumpage from the aquifer may be simulated efficiently.

In the process of evaluating alternative regional water plans, consideration of seasonal and peak day water demands was essential to ensure that sufficient water treatment and distribution capacities would be included.  Daily variations in water supplied by the San Antonio Water System during 1996 were assumed representative of typical urban areas during drought.  For planning purposes, it has been assumed that regional water treatment and distribution facilities would be developed to serve multiple user groups with water from multiple sources, thereby realizing economies of scale.  Considering the dependable annual supply and transmission capacity associated with each of the various water supply options comprising an alternative plan as well as the daily variations in water demand, small reservoirs providing balancing storage were sized and located near regional water treatment facilities in Bexar, Comal, and Hays Counties.

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);[4]

·        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.

 

5.2.2    County Summaries

Water management strategies recommended for implementation to meet projected needs or shortages in each of the 21 counties within the South Central Texas Region are summarized in Tables 5.2-2 through 5.2-22 and Figures 5.2-1 through 5.2-25 (Atascosa County: Graph and Table,   Bexar County: Graph  and Table ,    Caldwell County:  Graph  and Table,    Calhoun County: Graph  and Table,    Comal County:  Graph  and Table,   DeWitt County: Graph and Table,   Dimmit County: Graph and Table,   Frio County: Graph  and Table,   Goliad County:  Graph and Table,    Gonzales County:  Graph and Table,                 Guadalupe County:  Graph and Table,   Hays County:  Graph and Table,   Karnes County:  Graph and Table,   Kendall County:  Graph and Table,   La Salle County:  Graph and Table,   Medina County:  Graph and Table,   Refugio County:  Graph and Table,   Uvalde County:  Graph and Table,   Victoria County:  Graph  and Table,   Wilson County:  Graph and Table,    Zavala County:  Graph  and Table ).  These tables and figures illustrate the phased implementation of water management strategies at the county level.  Counties are presented in alphabetical order from Atascosa County to Zavala County.  The counties having the greatest municipal, industrial, steam-electric, and mining needs and, hence, the greatest quantities of new water supply are Bexar, Comal, Hays, and Guadalupe.  Particular attention to the notes at the base of each county table is encouraged.  More detailed information regarding allocation of new water supplies to specific cities and other water user groups within each county may be found in Section 5.3. (Atascosa County Surplus/Shortage - Tables 5.3.1-1 to 19, BexarCounty Surplus/Shortage, Caldwell County Surplus/Shortage,   CalhounCounty Surplus/Shortage,  ComalCounty Surplus/Shortage,  DeWittCounty Surplus/Shortage, DimmitCounty Surplus/Shortage, FrioCounty Surplus/Shortage,  GoliadCounty Surplus/Shortage,   Gonzales County Surplus/Shortage, Guadalupe County Surplus/Shortage, Hays County Surplus/Shortage, KarnesCounty Surplus/Shortage ,  Kendall County Surplus/Shortage, LaSalleCounty Surplus/Shortage,  Medina County Surplus/Shortage, RefugioCounty Surplus/Shortage ,  Uvalde County Surplus/Shortage ,  VictoriaCounty Surplus/Shortage ,  Wilson County Surplus/Shortage,  ZavalaCounty Surplus/Shortage)

5.2.3    Water Management Strategies

Following is a brief description of each of the water management strategies included in the South Central Texas Regional Water Plan along with the associated dependable water supply during drought.

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

Management strategy includes municipal water conservation practices and programs to reduce per capita water use in cities by amounts in addition to reductions already incorporated into the TWDB advanced water conservation case water demand projections.  Planned additional municipal water conservation focused on public education programs, accelerated retrofit of toilets, and changes in lawn irrigation could effectively increase supply through demand reduction in the South Central Texas Region by about 44,600 acft/yr in the year 2050.  Volume III, Section 1.1 includes a detailed discussion of this management strategy.

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

Management strategy achieves water conservation through the installation of Low Energy Precision Application (LEPA) irrigation systems and furrow dikes.  Planned implementation of these conservation measures in Bexar, Medina, Uvalde, Atascosa, Frio, and Zavala Counties could effectively increase supply for irrigation through demand reduction by about 28,900 acft/yr after adjustment for planned Edwards Irrigation Transfers (L-15).  Volume III, Section 1.1 includes a detailed discussion of this management strategy.

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

Management strategy involves voluntary transfer of water conserved through the installation of Low Energy Precision Application (LEPA) irrigation systems and furrow dikes on farms obtaining supplies from the Edwards Aquifer to municipal users.  Planned implementation of these conservation measures on about 53 percent of applicable acreage in Bexar, Medina, and Uvalde Counties could effectively increase municipal water supply for Bexar County by about 27,300 acft/yr (85 percent of 32,134 acft/yr), after adjustment for planned Edwards Irrigation Transfers (L-15) and consideration of Critical Period Management reductions during drought.

Edwards Irrigation Transfers (L-15)

Management strategy is based upon the provisions of Senate Bill 1477, as amended, which provides for the creation of the Edwards Aquifer Authority, establishes a withdrawal permit system, and potentially allows a permit holder to sell or lease up to 50 percent of his irrigation rights.  Planned voluntary transfers of 50,219 acft/yr (about 53 percent of eligible proposed Edwards irrigation rights in Bexar, Medina, and Uvalde Counties totaling 95,430 acft/yr) could effectively increase municipal water supply by about 42,700 acft/yr (85 percent of 50,219 acft/yr), after consideration of Critical Period Management reductions during drought.  Volume III, Section 1.3 includes a detailed  discussion of this management strategy.

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

Management strategy involves the construction of recharge enhancement structures located atop the Edwards Aquifer recharge zone (Type 2 Projects) on streams that are often dry.  These structures impound water only for a few days or weeks following storm events and recharge water very quickly to the aquifer, typically draining at a rate of 2 to 3 feet per day.  Planned projects include Indian Creek, Lower Frio, Lower Sabinal, Lower Hondo, Lower Verde, San Geronimo, Northern Bexar / Medina County Projects (Limekiln, Culebra, Government Canyon, Deep Creek, Salado Dam No. 3), Salado Creek FRS, Cibolo Dam No. 1, Dry Comal, and Lower Blanco.  Consensus Environmental Criteria were applied in the technical evaluations of projects comprising this management strategy located on streams which typically flow.  Summaries of applicable instream flow criteria are included in Volume III, Appendix F. Implementation of these projects could enhance spring discharge and increase dependable municipal water supply for Bexar County by about 21,600 acft/yr.  It is specifically recognized by the SCTRWPG that alternative projects at these locations that may be larger in size and storage capacity are consistent with the Regional Water Plan.  Volume III, Section 2.2 includes a detailed discussion of this management strategy.

Canyon Reservoir – River Diversion (G-15C)

Management strategy involves the purchase of stored water from Canyon Reservoir made available by amendment of Certificate of Adjudication No. 18-2074 to authorize additional diversions.  An application for this amendment has been submitted by the Guadalupe-Blanco River Authority (GBRA) and is presently under consideration by the Texas Natural Resource Conservation Commission (TNRCC).  Planned implementation of this strategy could include diversion from Lake Nolte, transmission and treatment facilities, and distribution of an additional dependable supply of about 15,700 acft/yr in Comal County.

Volume III, Section 4.1 includes a detailed discussion of a water supply option identified as Canyon Lake Water Released to Lake Nolte – Treated Water to Distribution System or Recharge Zone.  The SCTRWPG has considered the utility of this management strategy as a potential new treated water supply to Comal, Guadalupe, and/or Hays Counties in the context of alternative regional water plans (Volume II) and has recommended its implementation to meet projected needs in Comal County in the Regional Water Plan.  Estimates of cost and assessments of environmental issues and cumulative effects of implementation are presented herein.

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

Management strategy involves the purchase of stored water from Canyon Reservoir made available by amendment of Certificate of Adjudication No. 18-2074 to authorize additional diversions.  An application for this amendment has been submitted by GBRA and is presently under consideration by the TNRCC.  Planned implementation of this strategy would include diversion from Canyon Reservoir, transmission and treatment facilities, and distribution of an additional dependable supply of about 1,350 acft/yr to the Cities of Wimberley, Woodcreek, and Blanco in rural Hays and Blanco Counties.

Lower Guadalupe River Diversions (SCTN-16)

Management strategy involves the diversion of water from the San Antonio River above the Guadalupe River Saltwater Barrier to two 25,000 acft off-channel reservoirs, transmission to a regional water treatment facility, and distribution in Bexar County.  Sources of water include presently underutilized surface water rights held by GBRA and Union Carbide Corporation (up to about 67,200 acft/yr), unappropriated streamflow, and groundwater from the Gulf Coast Aquifer (up to 20,000 acft/yr).  Planned implementation of this strategy will provide a dependable supply of about 94,500 acft/yr beginning in 2010. Based on long-term averages derived from monthly simulations over a 56 year historical period, this dependable supply is comprised of 66,200 acft/yr available under existing water rights, 20,200 acft/yr available as unappropriated streamflow, 11,200 acft/yr available as groundwater from the Gulf Coast Aquifer, and a loss of 3,100 acft/yr to net evaporation from the off-channel reservoirs.  The off‑channel reservoirs would be located in Refugio, Victoria, or Calhoun Counties proximate to the diversion facilities.  Technical evaluations of this management strategy have assumed that this off-channel storage will be in the form of reservoirs created by two “ring-dike” embankments and will have no contributing drainage area.  Consensus Environmental Criteria were applied in the technical evaluation of this management strategy.  Summaries of applicable instream flow criteria are included in Volume III, Appendix F.

New Colorado River Diversion Option (LCRA)

Management strategy is based on a July 6, 2000 proposal by the Lower Colorado River Authority (LCRA) and involves the diversion of water from the Colorado River near Bastrop and Bay City to off-channel reservoirs, transmission to regional water treatment facilities, and distribution in Hays and Bexar Counties.  Sources of water include presently underutilized surface water rights, stored water from the Highland Lakes System, and groundwater from the Gulf Coast Aquifer.  Planned implementation of this strategy will provide a dependable supply of about 150,000 acft/yr to the South Central Texas Region in 2050 as well as an additional 180,000 acft/yr to meet irrigation needs in the Lower Colorado Region.

The SCTRWPG has, with certain qualifications, adopted this management strategy and its associated facilities necessary to provide for a new supply of 150,000 acft/yr as proposed by the LCRA and Region K.  The recommended management strategy includes approximately 100,000 acft of off-channel storage to be located in Wharton and Matagorda Counties.  Estimates of cost have assumed that this off-channel storage will be in the form of reservoirs created by four “ring-dike” embankments and having no contributing drainage area.  Potential sharing of costs for such associated facilities is a subject of on-going negotiations.  Estimated costs for purchase of water from the LCRA shown in the Regional Water Plan are based on LCRA’s current in-basin rate of $105 acft/yr plus a 25 percent out-of-basin surcharge.  Ultimate costs for purchase of water will be a subject of negotiation.

The SCTRWPG has been informed that evaluations of this option have been completed by Region K in accordance with applicable law.  The SCTRWPG is also cognizant of various comments and concerns regarding potential effects of this option on instream flows and freshwater inflows to bays and estuaries and has included summary information provided by LCRA regarding potential changes in streamflow in Section 5.2.4.  As the quantity of water which may ultimately be made available to Region L by the LCRA and Region K is uncertain at this time, the SCTRWPG has included the originally proposed quantity of 150,000 acft/yr in the Regional Water Plan.[5]  More specifically, the Plan includes up to 18,000 acft/yr diverted near Bastrop for delivery to Hays County and up to 132,000 acft/yr diverted near Bay City for delivery to Bexar County.

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

Management strategy involves the immediate development of well fields in the Carrizo Aquifer in northern Wilson and southern Gonzales Counties, a collection system, transmission to a regional water treatment facility, and distribution in Bexar County.  Strategy has been formulated subject to the rules and policies of the Evergreen and Gonzales County Underground Water Conservation Districts.  Planned implementation of this strategy includes annual production of approximately 11,000 acft and 5,000 acft from Wilson and Gonzales Counties, respectively, throughout the 50-year planning period.

Volume III, Section 6.1 includes a detailed discussion of water supply options identified as Carrizo-Wilcox Aquifer between San Marcos and Frio Rivers which involve the potential production of either 40,000 acft/yr or 75,000 acft/yr from new well fields in Wilson and Gonzales Counties.  Upon consideration of simulated Carrizo Aquifer drawdown associated with these production rates in the context of alternative regional water plans (Volume II), the SCTRWPG has included the production rate of 16,000 acft/yr in the Regional Water Plan.  The cumulative effects of implementation and long-term operation of this management strategy, as included in the Regional Water Plan, are summarized in Section 5.2.4.

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

Management strategy involves the phased development of well fields in the Carrizo Aquifer in northern Gonzales and southern Bastrop Counties, a collection system, transmission to a regional water treatment facility, and distribution in Comal and Guadalupe Counties.  Strategy has been formulated subject to the rules and policies of the Gonzales County Underground Water Conservation District and consideration of the draft rules of the Lost Pines Groundwater Conservation District.  Well field development in southern Bastrop County is not expected to occur prior to the year 2040.  Planned implementation of this strategy includes maximum annual production of approximately 15,000 acft and 12,500 acft from Gonzales and Bastrop Counties, respectively, in 2050.

Volume III, Section 6.2 includes a detailed discussion of a water supply option identified as Carrizo-Wilcox Aquifer between Colorado and Frio Rivers which involves the potential production of 220,000 acft/yr from new well fields in Atascosa, Wilson, Gonzales, and Bastrop Counties.  Upon consideration of simulated Carrizo Aquifer drawdown associated with production rates of 58,500 acft/yr and 90,000 acft/yr from Gonzales and Bastrop Counties in the context of alternative regional water plans (Volume II), the SCTRWPG has included a maximum production rate of 27,500 acft/yr in the Regional Water Plan at year 2050.  The cumulative effects of implementation and long-term operation of this management strategy, as included in the Regional Water Plan, are summarized in Section 5.2.4.  It is noted that the Region L estimates of groundwater production in Bastrop County exceed Region K estimates of availability in and beyond year 2030.  The two Regional Water Planning Groups have agreed that discussion of differences will be more productive upon completion of the new Groundwater Water Availability Models presently under development by the TWDB.

Carrizo Aquifer – Local Supply (SCTN-2a)

Management strategy involves the phased development or expansion of well fields in the Carrizo Aquifer for the purpose of meeting local municipal, industrial, steam-electric, or mining needs in Atascosa, Caldwell, Dimmit, and Wilson Counties.  Planned implementation of this strategy provides new dependable supplies totaling about 14,700 acft/yr for the South Central Texas Region in 2050.

Simsboro Aquifer (SCTN-3c)

Management strategy involves the phased development and expansion of well fields in the Simsboro Aquifer in Milam, Lee, and Bastrop Counties for the purposes of facilitating on-going mining operations and production of municipal and industrial water supply.  Implementation of this management strategy maximizes the beneficial use of water that is pumped to depressurize the mines by developing collection, transmission, treatment, and distribution facilities for use in Bexar County as opposed to being discharged into local streams for disposal.  Planned implementation of this strategy will provide a dependable annual supply of approximately 55,000 acft throughout the 50-year planning period.

Projected pumpage associated with this management strategy is consistent with the Brazos G Initially Prepared Regional Water Plan (Milam and Lee Counties) for the entire 50‑year planning period.  Projected pumpage in Bastrop County after 2020, however, exceeds the current estimate of available supply adopted by the Lower Colorado Regional Water Planning Group (Region K).  Periodic discussions between representatives of the South Central Texas and Lower Colorado Regions have focused on concerns regarding potential water level declines in the outcrop of the Simsboro Aquifer, three different groundwater models of the area, mitigation of impacts to affected wells, and equitable treatment of property owners within a groundwater district.  Differences between Region L’s projected pumpage and Region K’s estimate of available supply are more than 20 years from the present while development of new Carrizo (Simsboro) Aquifer Groundwater Availability Models (GAMs) under Texas Water Development Board direction is to be completed by about 2002.  Hence, it has been agreed that discussions will be more productive upon completion of the GAMs at which time additional scientific information will be available to both regions.

Volume III, Section 6.3 includes a detailed discussion of a water supply option identified as Simsboro Aquifer – Bastrop, Lee, and Milam Counties with Delivery to a Major Municipal Demand Center which involves the potential production of 75,000 acft/yr from new and existing well fields.  Subsequent to the completion this analysis in late 1999, the San Antonio Water System completed a study of its own[6] and recommended that a production rate of 55,000 acft/yr be considered in the technical evaluation of alternative regional water plans in which this management strategy would be included.  The cumulative effects of implementation and long-term operation of this management strategy, as included in the Regional Water Plan, are summarized in Section 5.2.4. 

SAWS Recycled Water Program (SAWS)

Management strategy involves the phased expansion of SAWS Recycled Water Program to provide dependable water supplies for non-potable uses and meet 20 percent of SAWS projected water demand.  Current SAWS Recycled Water Program is capable of delivering about 35,000 acft/yr and consumptive reuse of about 25,000 acft/yr is included as current supply.  Planned phased implementation of this management strategy will provide an additional dependable annual supply of about 19,800 acft in 2010 and about 52,200 acft in 2050.

This management strategy involves the continued implementation and expected future expansion of the SAWS Recycled Water Program.  Facilities for future expansion are expected to include Southern Interconnections between the Leon Creek, Dos Rios, and Salado Creek wastewater treatment facilities as well as a Northern Interconnection linking the Leon Creek and Salado Creek transmission lines.  Costs for expected future expansion are based on actual costs for implementation to-date and are included in the Regional Water Plan.

The SCTRWPG recognizes that SAWS and other water suppliers throughout the region may choose to reuse or reclaim the increased treated wastewater volumes associated with increased municipal water use, especially such wastewater volumes derived from privately owned groundwater and interbasin transfer of surface water.  The SCTRWPG further recognizes that this reuse may be accomplished directly (“flange-to-flange”) or indirectly through bed and banks delivery to downstream diversion and/or storage sites subject to applicable low.  Such lawful reuse of treated wastewater is consistent with the South Central Texas Regional Water Plan.

Purchase Water from Major Provider (PMP)

Management strategy involves the purchase of water supplies from, or participation in the development of new water supplies with, an identified Major Water Provider.  Major water providers include the San Antonio Water System (SAWS), Bexar Metropolitan Water District (BMWD), Guadalupe-Blanco River Authority (GBRA), City of New Braunfels, City of San Marcos, and Canyon Regional Water Authority (CRWA).  This strategy may also involve the purchase of water supplies from, or participation in the development of new water supplies with, the Regional Water Provider(s) for Bexar County.

Three purchases of water from major providers have been specifically identified in the Regional Water Plan and total 14,240 acft/yr.  The largest of these involves the phased purchase of up to 8,000 acft/yr by Kendall County water user groups from the Regional Water Provider for Bexar County or another major provider.  Costs for this management strategy include those for purchase, treatment, transmission, and distribution of water and are based on detailed feasibility studies for the Western Canyon Regional Water Supply Project.  The Plan includes a purchase of 5,000 acft/yr by the City of San Marcos from the Guadalupe-Blanco River Authority (GBRA) for diversion at Lake Dunlap and transmission in an existing pipeline to a regional treatment facility at San Marcos.  Costs include those for water purchase, expansion of the treatment facility, and distribution.  The Plan also includes the purchase of 1,240 acft/yr by the City of Victoria from GBRA.  This additional water supply would be delivered from Canyon Reservoir via the Guadalupe River and diverted, treated, and distributed using primarily existing facilities.

Desalination of Seawater (SCTN-17)

Management strategy involves the long-term development of intake and treatment facilities on the north shore of San Antonio Bay near Seadrift and transmission of treated water for distribution in Bexar County.  This management strategy utilizes a source of water that is essentially unlimited; however, costs of treatment and location for brine discharge (as may affect marine habitat and species) remain concerns.  Planned implementation of this strategy will provide a dependable annual supply of approximately 56,000 acft beginning in 2040 and increasing to about 84,000 acft by 2050.  Volume III, Section 1.10 includes a detailed discussion of this management strategy.

The SCTRWPG also considered an alternative water supply option involving desalination of seawater[7] sponsored by the TWDB and the Lavaca Regional Water Planning Group (Region P).  This option would include intake and treatment facilities at the Joslin Steam-Electric Station near Point Comfort with additional facilities for transmission to and distribution within Bexar County.  The option has not been included in the Regional Water Plan because the intake is located in an estuary reportedly having sediments contaminated with mercury and Polycyclic Aromatic Hydrocarbons[8].  In addition, the Calhoun County Navigation District has communicated to members of the SCTRWPG that the location of such a facility is unacceptable because of potential liability to the District.  Should these matters be favorably resolved, the SCTRWPG may consider amendment of the Regional Water Plan at some time in the future.

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

Management strategy involves the immediate development of SAWS planned 60 mgd aquifer storage and recovery (ASR) system in southern Bexar County so that supplies available from the Edwards Aquifer in winter months may be stored in the Carrizo Aquifer for subsequent recovery in the summer months, thereby substantially reducing peak municipal demands on the Edwards Aquifer during the summer.  Planned implementation of this strategy does not increase overall water supply on an annual basis, but does increase the reliability of current supplies for all municipal water user groups dependent upon the Edwards Aquifer.  While Volume III, Section 6.8 includes detailed discussions of similar management strategies, the specific strategy included in the Regional Water Plan is best described in a report prepared for SAWS.[9]

Schertz-Seguin Water Supply Project (SSWSP)

Management strategy involves the development of a well field located primarily in southern Gonzales County by the Schertz-Seguin Local Government Corporation and is currently in the implementation phase.  This Corporation will be responsible for creating and operating a wholesale water supply system to serve the long-term needs of these two communities located in Guadalupe and Bexar Counties.  Planned implementation of this strategy will provide a dependable annual supply of approximately 20,000 acft.

Western Canyon Regional Water Supply Project (WCRWSP)

Management strategy is currently in the implementation phase and involves the development of a water treatment plant west of Canyon Reservoir and a water transmission system to deliver treated water to project participants.  This strategy is dependent upon the amendment of Certificate of Adjudication No. 18-2074 authorizing additional diversions from

Canyon Reservoir which is currently pending before the Texas Natural Resource Conservation Commission.  Planned implementation of this strategy by the Guadalupe-Blanco River Authority will provide a dependable annual supply of approximately 10,500 acft to participants including the Bulverde Utility Company, Apex Water Services, Comal Independent School District, City of Boerne, City of Fair Oaks Ranch, San Antonio Water System, Bexar Metropolitan Water District, and San Antonio River Authority.

Hays/IH35 Water Supply Project

Management strategy is currently in the implementation phase and involves the delivery of stored water from Canyon Reservoir via a diversion facility at Lake Dunlap and transmission pipeline paralleling IH 35 to supply water user groups in Hays County.  A regional water treatment plant near San Marcos and a raw water pipeline connecting the plant to Lake Dunlap have been completed to-date.  Planned facilities include a potable water pipeline from the San Marcos Water Treatment Plant to the City of Kyle, Creedmoor-Maha, City of Buda, and other county entities.

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

Management strategy is a part of the Canyon Regional Water Authority plan, and is currently in the design and construction phase.  The Lake Dunlap WTP Expansion and Mid-Cities Water Transmission System will supply approximately 5,200 acft/yr of additional supply to Canyon Regional Water Authority’s member entities which include Crystal Clear WSC, Springs Hill WSC, Green Valley SUD, East Central WSC, City of Marion, City of Cibolo, and BMWD (NE Service Area).  The water will be diverted from Lake Dunlap north of the City of Seguin and delivered via a new pipeline network to those participating entities. 

Carrizo Aquifer – Bexar & Guadalupe (BMWD)

Management strategy is a part of Bexar Metropolitan Municipal Water District (BMWD) plan.  The strategy is being implemented and will supply about 4,000 acft/yr to BMWD to supply to its customers in southern and northeastern Bexar County. 

Trinity Aquifer – Bexar (BMWD)

Management strategy is a part of Bexar Metropolitan Municipal Water District (BMWD) plan.  The strategy is in the process of being implemented and is estimated to supply about 1,000 acft/yr to BMWD to supply to its customers in Northern Bexar County.

Canyon Reservoir Contract Renewal (GBRA)

Management strategy is renewal of existing contracts with New Braunfels (December 5, 2001 expiration) for 6,700 acft/yr, with San Marcos (July 7, 2047 expiration) for 5,000 acft/yr, with Kyle (December 31, 2038 expiration) for 589 acft/yr, and with Port Lavaca (February 20, 2008 expiration) for 1,500 acft/yr.  Other existing Canyon Reservoir contracts remain in force throughout the planning period or are assumed to be renewed upon expiration.

Brush Management (SCTN-4)

Management strategy involves the selective removal of brush from rangeland watersheds in counties of the South Central Texas Region located in the Edwards Plateau Vegetational Area or having significant projected shortages.  In other counties, it is assumed that the quantities of brush are not large enough to produce water supply benefits.  There are 1.1 million acres of brush infested land in the 12.8 million acre planning region.  The practice has been studied, some watersheds have been treated and others are presently being selectively cleared.  The Texas State Soil and Water Conservation Board, and agencies of the U.S. Department of Agriculture have landowner cost sharing and technical assistance programs for well-planned wildlife habitat compatible brush management/clearing programs.  Although it is not possible to estimate the quantities of water that this strategy would contribute during drought, the strategy could contribute to increased streamflows and increased aquifer recharge during non-drought periods.  To the extent that such additions to these water resources are stored for use later, the strategy could contribute to supplies available during drought.  The water from this strategy would be available for development or recovery by individual water user groups and by water suppliers that serve several different water user groups.

Weather Modification (SCTN-5)

Management strategy involves the seeding of clouds with silver iodide by licensed professionals to increase precipitation within the planning region.  This management strategy has been studied and is being practiced in 15 counties of the region’s 21 county area at the present time. Although it is not possible to estimate the quantities of water that this strategy would contribute during drought, the strategy could contribute to increased precipitation on rangeland and cropland, as well as increasing stream flows and aquifer recharge during non-drought periods.  Increased precipitation on range and cropland would contribute directly to crop, livestock, and wildlife production, and in the case of irrigated crop production would reduce the need to apply irrigation water. To the extent that such additions to these water resources are stored for use later, the strategy could contribute to supplies available during drought.  The water from this strategy would be available for development or recovery by individual water user groups and by water suppliers that serve several different water user groups.

Rainwater Harvesting (SCTN-9)

Management strategy is the catching and storing of rainwater from roofs of homes and other buildings largely for use at or very near the sites from which the water is caught.  The strategy is being used in parts of the South Central Texas Planning Region for household water supplies for both potable and non-potable uses.  Although this strategy is limited due to rainfall levels, time of rainfall events, and capacities of storage facilities, the strategy can supply a part, or in some cases all, of the water needed by individual households and business establishments in areas that are too distant or too sparsely settled to be served efficiently by public systems.  Rainwater harvesting in the Trinity Aquifer area of the region (Northern Bexar, Comal, Hays, Medina, and Uvalde Counties) can supplement supplies from wells completed in this aquifer, and thereby extend the capabilities of this aquifer to support the demands that are projected to be placed upon it. 

Additional Municipal Recycling (Reuse) Programs

Management strategy involves expansion of programs that reclaim municipal wastewater for non-potable uses such as irrigation of golf courses, parks, and open spaces of cities, landscape watering of large office and business complexes, cooling of large office and business complexes, steam-electric power plant cooling, irrigation of farms that produce livestock feed and forage, irrigation of farms that produce sod, ornamentals, and landscape plants, and for instream uses such as river walks and waterways.  This strategy is being used within the region by entities including SAWS, SARA, and CCMA and can be expanded as the quantities of municipal wastewater increase with population growth.  An advantage of this strategy is that the water has already been developed and brought to the locations of many of the uses listed above.  With additional treatment, this water can be reclaimed for further use, as opposed to being discharged for disposal, at a cost to the municipalities that have used it once.

The SCTRWPG recognizes that SAWS, SARA, CCMA, and other water suppliers throughout the region may choose to reuse or reclaim the increased treated wastewater volumes associated with increased municipal water use, especially such wastewater volumes derived from privately owned groundwater and interbasin transfer of surface water. The SCTRWPG further recognizes that this reuse may be accomplished directly (“flange-to-flange”) or indirectly through bed and banks delivery to downstream diversion and/or storage sites subject to applicable law.  Such lawful reuse of treated wastewater is consistent with the South Central Texas Regional Water Plan.

Small Aquifer Recharge Dams

Management strategy is the construction of small dams on ephemeral waterways to capture runoff and hold it for seepage into aquifers of the planning region.  The strategy is needed and appears to be applicable in the northern parts of the northern counties of the South Central Texas Water Planning Region overlying the Trinity Group of Aquifers that are being heavily stressed by a rapidly growing population.  This strategy can be implemented by individual landowners of the area, but would probably need cost sharing by organized groups who obtain and depend upon the aquifers to be recharged, and to the extent that such structures reduce soil erosion, may qualify for technical and financial assistance from state and federal agencies. 

Edwards Aquifer Recharge & Recirculation Systems

Management strategy involves artificial recharge of the Edwards Aquifer, capture of the resulting increased springflows, and returning these quantities of water to further recharge the aquifer.  Artificial recharge could be done using runoff from the Edwards Plateau, water imported from other watersheds, the subsequent increment of springflow resulting from artificial recharge, and/or a combination of these sources.  The purpose of this strategy is to maintain springflows at satisfactory levels to protect the habitats of endangered species that exist in the springs and specified reaches of spring fed streams, while at the same time increasing the quantity of water that can be withdrawn from the aquifer to meet the needs of water user groups.  The quantities of water that could be withdrawn from the aquifer depend upon the quantities of recharge, the location(s) at which the recharge is made to the aquifer, levels of the aquifer at the time of recharge, residence time of recharged water in the aquifer, and perhaps other factors that are not known or well understood.  The major reason for the Recharge and Recirculation strategy is to use the aquifer to store and distribute water to water user groups that have already established themselves in proximity to the aquifer. 

Cooperation with Corpus Christi for New Water Sources

Management strategy involves cooperation and partnership with Corpus Christi of the Coastal Bend Water Planning Region (Region N) in the development of additional or “New Water Sources.”  The potentials include desalination, surface water from the Lower Colorado River that might be conveyed via Corpus Christi’s Mary Rhodes Pipeline from Lake Texana to the City of Corpus Christi in exchange for water to recharge the Edwards Aquifer that is now included in Corpus Christi’s permit for Choke Canyon Reservoir, groundwater along and near the Mary Rhodes Pipeline, surface water from the Brazos River Basin via the Mary Rhodes Pipeline, and perhaps other sources in or adjacent to the coastal areas of Regions L and N.  In any case, the objective of this option is benefit both regions by improving efficiency and lowering costs of developing New Sources of water for both regions.  One of the ways to accomplish parts of this objective is to increase the usage of already existing facilities and sources of water. 

Additional Storage (ASR and/or Surface)

Management strategy involves implementing large, regional scale ASR and/or surface storage facilities adequate in size to store surplus flows of surface water during periods of high streamflows, including flood flows, to be available during extended periods of drought.  Present management strategies of the South Central Texas Regional Water Plan are sized and scheduled to meet seasonal and daily variations of demand, but some current supplies may not be fully reliable during extended or multi-year droughts.  Thus the need for surface reservoirs, large scale ASR Systems, or multipurpose reservoirs.  If the water management issue is a supply for emergencies or drought, water could be stored in the Carrizo or Gulf Coast Aquifers for several years before it is recovered.  Water treatment capacity necessary to meet peak day demands may be available at non-peak times (fall, winter, and spring) to treat water for aquifer storage and subsequent recovery.

Lockhart Reservoir (G-21)

The Lockhart Reservoir is recommended as a potential reservoir site. Although the Regional Water 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 RWPG will review the Lockhart Reservoir water supply option as a possible amendment to the Regional Water Plan.

 


[1] HDR Engineering, Inc., “Water Availability in the Guadalupe – San Antonio River Basin,” Texas Natural Resource Conservation Commission, December 1999.

[2] Klemt, W.B., Knowles, T.R., Elder, G.R., and Sieh, T.W., “Ground-water Resources and Model Applications for the Edwards (Balcones Faulty Zone) Aquifer in the San Antonio Region, Texas,” Texas Water Development Board Report 239, 1979.

[3] Thorkildsen, D. and McElhaney, P.D.., “Model Refinement and Applications for the Edwards (Balcones Fault Zone) Aquifer in the San Antonio Region, Texas,” Texas Water Development Board Report 340, 1992.

[4] 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.

[5] 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 the Regional Water Plans for 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 could 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 wtihin the Region L plan to compensate for the proposed reduction in yield of the project.

[6] HDR Engineering, Inc. and Paul Price Associates, Inc., “Preliminary Feasibility of Options to Deliver Alcoa/CPS Groundwater to Bexar County,” San Antonio Water System, January 2000.

[7] Turner, Collie & Braden, Inc., “Investigation of Joslin Steam Electric Station for Co-Location of a Desalination Facility,” Lavaca Regional Water Planning Group in Conjunction with Region L and N Planning Groups, June 2000.

[8] U.S. Environmental Protection Agency, “Alcoa/Lavaca Bay, Texas,” EPA ID# TXD008123168, EPA Region 6, February 2, 2000.

[9] CH2M Hill, “Aquifer Storage Recovery Project, Preliminary Investigation and Feasibility Analysis Step 2 Report,” San Antonio Water System, February 2000.