5.2.6 Implementation Issues

5.2.6.1 Summary of Key Information

Pursuant to TAC 357.7(a)(7), regional water plan development shall include evaluations of water management strategies providing certain key information pursuant to TWDB criteria. Key information regarding the South Central Texas Regional Water Plan is summarized by subject area below. In addition, Table 5.2-25 provides a summary of key information, pursuant to TWDB evaluation criteria, for each water management strategy included in the Regional Water Plan.

Quantity, Reliability, and Cost

· Plan reflects substantial commitment to Municipal and Irrigation Demand Reduction (Conservation) (L-10) throughout the South Central Texas Region, thereby encouraging efficient utilization of existing water supplies and reducing quantities of new supply needed.

· Plan includes reliable new water supplies sufficient to meet projected drought needs for municipal, industrial, steam-electric power, and mining uses through the year 2050.

· Plan recognizes that water management strategies such as brush management, weather modification, rainwater harvesting, and small recharge dams contribute positively to storage and system management of diverse sources of supply.

· Annual costs associated with new supplies delivered to each water user group range from about $120,000,000 dollars early in the planning period to about $420,000,000 in 2040. Unit costs range from $530 per acft to $737 per acft and average $617 per acft or $1.89 per 1,000 gallons over the 50-year planning period.

· During the more immediate planning period extending through 2030, the Regional Water Plan has the least average unit cost of the alternative plans considered.

Environmental Factors

· See Section 5.2.6.2 for summary of environmental benefits and concerns.

Impacts on Water Resources

· Plan implementation results in no unmitigated reductions in water available to existing rights.

· Generally modest long-term reductions in water levels in the Carrizo Aquifer as withdrawals associated with management strategies in the Plan are in conformance with the policies of the Evergreen and Gonzales County Underground Water Conservation Districts.

Impacts on Agricultural and Natural Resources

Inclusion of water management strategies to meet projected irrigation needs (shortages) in full is estimated to be economically infeasible at this time. Irrigation Demand Reduction

(Conservation) (L-10 Irr.) through the installation of Low Energy Precision Application (LEPA) systems is recommended to offset a portion of projected irrigation needs (shortages) in six counties.

· Plan includes Brush Management (SCTN-4) and Weather Modification (SCTN-5) which are expected to contribute positively to storage and system management of diverse water management strategies. Weather Modification (SCTN-5) assists irrigation and dry-land agriculture (crops and ranching) and increases water supply for wildlife habitat.

· Plan includes about 53 percent of potential maximum voluntary transfer of Edwards Aquifer irrigation permits to municipal use through lease or purchase.

· Plan includes installation of LEPA systems on about 53 percent of applicable acreage in Uvalde, Medina, and Bexar Counties with conserved water being transferred to municipal use.

Other Relevant Factors per SCTRWPG

· Potential effects of Plan implementation on Edwards Aquifer springflows has been identified as a relevant factor by the South Central Texas Regional Water Planning Group (SCTRWPG). As shown in Section 5.2.3, implementation of Plan is expected to increase discharges from both Comal Springs and San Marcos Springs.

· Flexibility in the phasing and order of implementation of management strategies comprising the Plan has been identified as a relevant factor or concern by the SCTRWPG. Major Water Providers and water user groups need the ability to expedite or reschedule implementation of any specific management strategy as necessary and appropriate.

Comparison of Strategies to Meet Needs

· Selection of water management strategies comprising the Regional Water Plan was based upon guiding principles and assumptions of the SCTRWPG as discussed in Section 6.3.

Interbasin Transfer Issues

· Plan includes at least three potential interbasin transfers: (a) from the Lower Colorado River near Bastrop to Hays County; (b) from the Lower Colorado River near Bay City to Bexar County; and (c) from San Antonio Bay near Seadrift to Bexar County. Interbasin transfer(s) may also be associated with Edwards Aquifer Recharge & Recirculation Systems once this management strategy is more completely defined.

· Projected needs (shortages) in basin(s) of origin are met throughout the planning period.

Third-Party Impacts of Voluntary Redistribution of Water

· Positive effects for municipal water user groups and potentially negative effects upon rural economies associated with Edwards Irrigation Transfers (L-15) and Irrigation Demand Reduction (Conservation) (L-10 Irr.) with Transfers.

· Payment to farmers for voluntary irrigation water transfer provides capital for farmers to install higher efficiency irrigation systems. In many cases, this allows irrigation to continue at present levels so that the transfer does not adversely affect the regional economy.

· Lower water levels in some portions of the Carrizo Aquifer.

Regional Efficiency

· Edwards Irrigation Transfers (L-15) require no new facilities. Transferred water would likely be available at or very near locations having projected municipal, industrial, steam-electric power, and mining needs in Uvalde, Medina, Atascosa, and Bexar Counties.

· Regional water treatment and balancing storage facilities in Bexar County increase efficiency, improve reliability, and reduce unit cost.

· San Antonio Water System Regional Aquifer Storage & Recovery System (SCTN-1a) substantially reduces peak summer pumpage from the Edwards Aquifer.

Effect on Navigation

· Not applicable.

5.2.6.2 Environmental Benefits and Concerns

The South Central Texas Regional Water Planning Group has identified the following environmental benefits and concerns associated with the implementation of the Regional Water Plan.

Environmental Benefits

· Substantial commitment to water conservation through adoption of Texas Water Development Board (TWDB) advanced conservation water demand projections results in fewer water management strategies necessary to meet projected water needs. The South Central Texas Region is the only planning region in the state to adopt the advanced conservation water demand projections.

· Additional commitment to accelerated conservation (above and beyond that in the TWDB’s advanced conservation water demand projections) through Demand Reduction (L-10) results in fewer water management strategies necessary to meet projected water needs. Demand Reduction (L-10) accounts for more than 22 percent of the total new water supplies for municipal, industrial, steam-electric, and mining uses in 2010. Even in 2050, Demand Reduction (L-10) accounts for more than 10 percent of the total new water supplies for the referenced uses.

· Development of new water supply sources for Bexar, Comal, and Hays Counties reduces reliance on the Edwards Aquifer during drought thereby contributing to maintenance of springflow and protection of endangered species. The Regional Water Plan recognizes the on-going initiatives of the Edwards Aquifer Authority (EAA) to develop a Habitat Conservation Plan and implement Critical Period Management rules which will help to define the requirements for maintenance of springflow and protection of endangered species.

· Phased implementation of the Regional Water Plan (including timely utilization of Management Supplies) results in increased instream flows in the Guadalupe and San Antonio Rivers and increased freshwater inflows to the Guadalupe Estuary, particularly during the drier months and more extended drought periods.

· Edwards Aquifer Recharge Enhancement through the construction of Type 2 recharge dams (L-18a) contributes not only to municipal water supply, but also to maintenance of springflow, protection of endangered species, increased instream flows, and increased freshwater inflows to the Guadalupe Estuary.

· The Regional Water Plan makes greatest beneficial use of existing surface water rights and major storage facilities (Canyon Reservoir, Highland Lakes System) thereby minimizing the development of new water supply sources and associated environmental impacts. Examples include reliance on presently under-utilized water rights held by the Guadalupe-Blanco River Authority (GBRA) and Union Carbide Corporation (UCC) below the confluence of the Guadalupe and San Antonio Rivers (SCTN-16) and by the Lower Colorado River Authority (LCRA) on the Lower Colorado River. Enhanced use of existing surface water rights and major storage facilities accounts for more than one third of the total new water supplies for municipal, industrial, steam-electric, and mining uses by 2050.

· The Regional Water Plan avoids large-scale development of new reservoirs having associated terrestrial and aquatic habitat and cultural resources impacts and focuses on smaller, off-channel balancing reservoirs essential for efficient operations and meeting peak seasonal water needs.

· Inclusion of Edwards Aquifer transfers from irrigation use to municipal use through lease/purchase of pumpage rights (L-15) and development of conserved water through installation of LEPA irrigation systems (L-10 Irr.) results in substantial increases in municipal water supply without construction of additional transmission and storage facilities having associated environmental effects.

· The San Antonio Water System (SAWS) goal of meeting 20 percent of projected water demand through its Recycled Water Program makes greatest use of developed water resulting in fewer water management strategies necessary to meet projected water needs.

· Inclusion of modest Carrizo Aquifer groundwater development (CZ-10C, CZ-10D, and SCTN-2a) has minimal associated environmental effects as compared to those typically associated with development of new surface water supplies.

· Inclusion of Desalination of Seawater (SCTN-17) is perceived to have fewer associated environmental effects, as compared to those typically associated with development of new (fresh) surface water supplies.

Environmental Concerns

· Potential reductions in freshwater inflows to bays and estuaries including associated effects on wetland and marsh habitats and marine species are identified as matters of concern. Primary concerns focus upon the potential effects of the New Colorado River Diversion Option (LCRA) on freshwater inflows to Matagorda Bay. Secondary concerns are identified for the Nueces Estuary as a result of implementation of Edwards Recharge—Type 2 Projects (L-18a).

· Concentration of Edwards Aquifer pumpage closer to Comal Springs as a result of implementation of Edwards Irrigation Transfers (L-15) and additional transfers of conserved water developed by installation of LEPA irrigation systems (L-10 Irr.) tends to reduce discharge from Comal Springs.

· Potential conflicts with stream segments identified by TPWD as ecologically significant are associated with the New Lower Colorado River Diversion Option (LCRA), Lower Guadalupe River Diversions (SCTN-16), and Edwards Recharge—Type 2 Projects (L-18a).

· Potential effects on small springs may be associated with the development of groundwater supplies from the Carrizo Aquifer (CZ-10C, CZ-10D, and SCTN-2a) and from the Simsboro Aquifer (SCTN-3c).

· Intake siting, brine discharge location(s), and potential effects on marine habitat and species are environmental concerns associated with Desalination of Seawater (SCTN-17).