SEGUIN – Guadalupe-Blanco River Authority (GBRA) officials are urging citizens in its 10-county statutory district, which includes Caldwell, Calhoun, Comal, DeWitt, Gonzales, Guadalupe, Hays, Kendal, Refugio and Victoria counties, to conserve water and comply with drought management measures implemented by local municipalities.
The water conservation plea comes amidst the U.S. Department of Agriculture’s recent declaration of 213 of Texas’ 254 counties as a natural disaster area as a result of the extreme drought conditions the state has faced since at least January.
Also contributing to the request for conservation are low flows throughout the basin. On July 10, 2011, United States Geological Survey (USGS) gauges read 1.4 cubic feet per second (cfs) for the inflow at Spring Branch into Canyon Reservoir. The median inflow at Spring Branch is 161 cfs. Flows at San Marcos Springs were down to 107 cfs (median flow is 164 cfs) and Comal Springs flows were down to 175 cfs (median flow is 308 cfs).
One bright spot is Canyon Reservoir with an elevation at 903.95 mean sea level (msl), which is 90% full, provides firm yield to water supply system customers. Canyon Reservoir is operated by GBRA for water supply and the U.S. Army Corps of Engineers for flood protection. The reservoir is refilled with flood flows and does not provide a constant elevation.
GBRA officials imposed Stage 2 restrictions on June 8 for residents who live along its Hydroelectric Lakes. The critical period applies to any diverter of water other than contracted stored water that diverts and uses water from any of the GBRA Hydroelectric Lakes ― Lake Dunlap (Comal and Guadalupe counties, Lake McQueeney (Guadalupe County), Lake Placid (Guadalupe County), Lake Nolte (Guadalupe County), H4 or Lake Gonzales and H5 or Lake Wood (both in Gonzales County). Stage 3 restrictions could be imposed if the average 24-hour spring flow rate at Comal Springs flows at or below 150 cfs.
On the lower end of the basin, the drought has similarly affected river flow. The gauge at Victoria read 260 cfs (median flow is 1010 cfs), triggering Stage 2 restrictions for the City of Victoria. Stage 2 enacts mandatory water restrictions on Victoria residents and limits landscape irrigation and other water uses. The flow into the San Antonio Bay and Estuary is around 400 cfs.
Other areas within GBRA’s statutory district, such as Boerne and Fair Oaks Ranch in Kendall County, have implemented and begun to enforce water restrictions. Several of the monitoring wells in the Trinity Aquifer are at historical low levels.
When flows drop below 150 cfs at Comal and 100 cfs at San Marcos, endangered species, including the Fountain Darter and the San Marcos Gambusia technically are in “jeopardy.” In addition to protecting endangered species, spring flows are important to water rights and even water supply in the Guadalupe and San Marcos rivers – a supply that is used by cities, industries and agricultural producers.
Prolonged high temperatures, at least 18 days of 100-plus degree temperatures recorded in some Central Texas locations during the month of June, and lack of rainfall are contributing to the declining water levels throughout the Guadalupe River Basin and the Edwards Aquifer.
The level of the Edwards Aquifer J-17 well was 644.4 on July 10. The Edwards Aquifer Authority triggers Stage 2 Critical Period at 650 msl, which demands 30 percent restrictions for aquifer users in Bexar, Medina and parts of Atascosa, Comal, Guadalupe, Hays and Calwell counties. Stage 3 Critical Period is triggered when J-17 reaches 640.
The GBRA was established by the Texas Legislature in 1933 as a water conservation and reclamation district. GBRA provides stewardship for the water resources in its 10-county statutory district, which begins near the headwaters of the Guadalupe and Blanco rivers, ends at San Antonio Bay, and includes Kendall, Comal, Hays, Caldwell, Guadalupe, Gonzales, DeWitt, Victoria, Calhoun, and Refugio counties.
