Rain brings increases in spring flow and groundwater levels

November 2021 Hydro Report

The wet conditions this Fall have boosted spring flow at area Middle Trinity springs.  Flow in the Blanco River peaked at 9,210 cfs on Oct. 14.  After runoff subsided, springs continue well above previous baseflow conditions.  Pre-rain conditions at Pleasant Valley and Park Springs on the Blanco River upstream of Fischer Store Road saw an increase in baseflow from 16 cfs to nearly 22 cfs.  Baseflow at Jacob’s Well increased from 2-3 cfs to just below is about 20 cfs.

Groundwater levels and spring flow fluctuate through time. Rainfall and pumping are the biggest factors influencing aquifer conditions. The Texas Water Development Board, in conjunction with many groundwater conservation districts, maintains monitor wells throughout the state (the data are publicly accessible on this web link). The water level in the Mt. Baldy monitor well (Middle Trinity) has responded to the influx of recharge.  Oftentimes, groundwater levels are slower to respond than spring flow, and the Mt. Baldy well measurements show only a slight delay, which shows the highly developed flowpaths within the Middle Trinity karst system.  Water level rise plateaued and has begun to decline again with lack of additional rain.

Mt Baldy Monitor Well – 30 day view hydrograph.
Mt. Baldy Monitor Well – Period of record view

While we can’t control the weather, we can conserve water and look for innovative ways to use alternate supplies (like site-harvested supplies—rainwater and AC condensate) to lessen impacts of pumping. Typically, the high water use period extends from May 1 – September 30. Less pumping and continued wet conditions could create much needed recharge and boost water levels and spring flow. While each aquifer behaves differently, all groundwater is limited and deserves to be used wisely. For more information on native landscapes, rainwater harvesting, leak identification tips and more, visit the Home Owner Resource page.

No matter what area agencies call their drought declaration, coordinated water conservation is important to preserve groundwater availability, spring flow, and water supplies.

Agency Drought Stage Date Declared Details
Hays Trinity GCD Jacob’s Well GMZ – 20% Curtailment
Remaining GCD – No Drought
Jun. 2021 Board Order, 6/3/2020
Barton Springs Edwards Aquifer CD No Curtailment Jul. 2021 Press Release, 7/8/2021
Edwards Aquifer Authority No Curtailment May 2021 Press Release, 5/7/2021

[Updated 11/14/2021]

For updates, useful links, and archived Hydro Reports, visit the WVWA Water Monitoring page.