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Region L - South Central Texas

2005 Regional Water Plan Overview

Regional Facts

Major Cities	San Antonio, Victoria
Population: 2000	2,042,221
Population: 2060	4,297,786
Total Water Use: 2000	896,353 Acre-Feet
Total Water Use: 2060	1,273,003 Acre-Feet
Primary Rivers	Guadalupe, San Antonio, Nueces, Lavaca-Guadalupe, San Antonio-Nueces
Major Aquifers	Edwards (BFZ), Trinity, Carrizo-Wilcox, Gulf Coast
Annual Precipitation	20-44 Inches
Net Evaporation	28-56 Inches

Basic Plan Facts

Population in the region is projected to more than double between 2000 and 2060
Total capital cost of water supply measures: Not Available
Off-channel reservoirs and diversions on the Lower Guadalupe and Lower Colorado Rivers are proposed
Proposed groundwater strategies result in long-term drawdown of water levels in aquifers
The Plan proposes projects significantly in excess of projected needs.

What's at Issue?

The San Antonio area faces major challenges because of the need to reduce dependence on the Edwards Aquifer in order to protect spring flows at Comal and San Marcos Springs and associated endangered and threatened species.

Several proposed water development projects could have significant effects on more of the principal rivers and associated bay and estuarine systems of our State. Components of the Region L plan have the potential to affect the ecological health of not only the San Antonio and Guadalupe Rivers but also the Colorado, Nueces, and Lavaca-Navidad Rivers. The plan also could have affects on several of the major estuarine systems of Texas: San Antonio Bay (Guadalupe Estuary), Corpus Christi (Nueces Estuary) and Matagorda Bays. A prominent example is the proposed Guadalupe River Diversion to San Antonio. This strategy would include serious reductions in freshwater inflows to the Guadalupe estuary, and threatens endangered Whooping Cranes at the Aransas National Wildlife Refuge. The San Antonio Water System has dropped their participation in the Guadalupe River Diversion Project. The Region L Planning Group has yet to remove the Project from the Plan however.

Groundwater projects in the Plan are projected to result in long-term drawdowns in the Trinity, Carrizo, and Gulf Coast Aquifers. These drawdowns could result in decreased springflow, decreased baseflow to rivers and estuaries, and increased pumping cost for local groundwater users. In some instances, the proposed volumes of pumpage from the projects exceed the recommendations of local groundwater control districts.

Action Items

Here are some of the items the Region L Planning Group must address.

Conservation and Drought Management
For conservation and drought management, the plan needs to...

Implement Irrigation Water Conservation Strategies. The plan assumes that irrigation conservation is being practiced to the extent feasible, despite the fact that 720,000 additional acres are not irrigated with center pivots.
Recognize the full potential for municipal conservation. The municipal conservation goal in the plan is the existing average of 172 gpcd (gallons per capita per day), well above the 140 gpcd recommended by the State Water Conservation Implementation Task Force.
Incorporate drought management as a water management strategy. Not considering existing local statutory limitations on non-essential water use during times of drought inflates demands that can lead to an overemphasis on costly water projects.

Environmental Flows
To secure the protection of flows for fish and wildlife, the plan needs to...

Include environmental water needs as a specifically recognized category of water demand that must be planned for.
Include in the discussions the numerous other springs in the area that have wildlife and ecological importance.
Designate stream segments in the region that meet the criteria as having "unique ecological value". No segments were designated in the 2006 regional plan. The Texas Parks and Wildlife Department recommends 20 segments for designation in this region.

Economics
To ensure that only the most economically sound water supply strategies are implemented, the plan needs to...

Recommend specific projects for meeting only the projected need. The Plan proposes projects that supply over 800,000 acre-feet/year, yet projected demands are only 417,000 acre-feet/year.