There are several key players when it comes to water monitoring in the Hill Country.  Each agency publishes data through different platforms and reports.  This page compiles useful references that can help get a more comprehensive view of water resources in the Hill Country.

Water levels and spring flow on the decline (again)
September 2021 Hydro Report

With above average rainfall for Central Texas, surface vegetation is thriving, rainwater catchment systems are full, but aquifer conditions aren’t doing as well. Water levels in monitor wells rose after this summer’s wet conditions, but they’ve started to decline again. Similarly, after summer rains baseflow increased from Middle Trinity springs (Jacob’s Well and Pleasant Valley Springs shown above), but flow is slowly decreasing.

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 and the data are publicly accessible on the web (link). Looking at annual trends for the Edwards, Middle Trinity, and Lower Trinity, there are similarities and differences. Comparing the annual graphs, each monitor well shows a water level rise after the wet conditions in late April through early June. The long term trends show recent declines in water levels over the past few years.

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 9/16/2021]

Annual rainfall average for Central Texas is approximately 33 inches per year.  To understand recharge potential, it’s important to track where rain falls, how fast it falls, and how saturated the soils are.  Key rain gages for the area are (upstream to downstream):

Realtime comparison of two key spring flow sites: (USGS gages: Blanco at Fischer Store–08170950 and Jacob’s Well–08170990)

Jacob’s Well Spring, Cypress Creek

Jacob’s Well is a Middle Trinity Aquifer spring that provides the baseflow for Cypress Creek.

    • Realtime data: USGS 08170990 Jacobs Well Spg nr Wimberley, TX
    • Spring flow is a strong indicator of groundwater levels in the Jacob’s Well Groundwater Management Zone (JW GMZ), because low spring flow directly correlates to low well water levels.
    • The 10-day average spring flow is a drought trigger for the HTGCD Jacob’s Well GMZ (Thresholds:  10% Curtailment: below 6 cfs; 20% Curtailment: below 5 cfs; 30% Curtailment: below 3 cfs).
    • Groundwater pumping causes 1 to 1.5 cfs fluctuation in flow and is more evident under low flow conditions.

Pleasant Valley and Park Spring, Blanco River

Pleasant Valley and Park Springs are Middle Trinity Aquifer springs that provide significant baseflow for the Blanco River, especially during dry periods.

The Hill Country’s iconic streams are known for their clear water and rocky bottoms.  Oftentimes, cracks, caves, and faults are visible in stream beds.  When creeks and rivers are flowing, these cracks, caves, and faults channel water from the surface into the groundwater system below.  Streamflow gages are strategically located to help monitor gaining (where springs are found) and losing (where recharge happens) sections of creeks and rivers. Key gages include:

Groundwater monitoring is an art.  TWDB, HTGCD, and BSEACD have extensive monitoring networks.

Key wells from west to east:

Archived Hydro Reports

Month   Cypress Creek – Jacob’s Well Blanco River – Pleasant Valley & Park Springs Date Published
2021 July Spring flow increased, Groundwater levels still low 3.9 cfs 33.2 cfs 7/6/2021
2021 May Recharge! 2.2 cfs 13.5 cfs 5/18/2021
2021 April Lowest Groundwater Level Recorded Since 2005 1.4 cfs 11.4 cfs 4/22/2021
2021 March 2.4 cfs 13.5 cfs 3/10/2021
2021 January 0.3 cfs 11.8 cfs 1/19/2021
2020 December 1.3 cfs 16.8 cfs 12/8/2020
2020 November 1.1 cfs 17.1 cfs 11/11/2020
2020 October 1.7 cfs 17.7 cfs 10/25/2020
2020 September 6.5 cfs 25.2 cfs 9/14/2020

Please note:  Page under construction.  Please email robingary@wimberleywatershed.org with suggestions or questions.