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.

November 2020 Hydro Report

No matter what area agencies call their drought declaration, it’s obvious water levels and spring flows have declined to exceptionally low levels. In order to preserve groundwater availability, coordinated water conservation measures are essential.

Groundwater Drought Declarations

Agency Drought Stage Date Declared Details
Hays Trinity GCD Jacob’s Well GMZ – 30% Curtailment
Remaining GCD – 20% Curtailment
Nov. 2020 Board Order, 11/1/2020
Barton Springs Edwards Aquifer CD Stage II Alarm Drought (20% Curtailment or more) Oct. 2020 Press Release, 10/9/2020
Edwards Aquifer Authority San Antonio Pool – Stage I Restrictions (20% Curtailment) Oct. 2020 Press Release, 10/16/2020

 

With dry soils, even the six inches of rain in early September did little to boost groundwater storage for the long term.  The plants and soils absorbed much of the moisture, so the rain did little to generate runoff and recharge.  This late in the dry season, it will take several consecutive rains to wet the soils before sustained recharge can refill the aquifers.

The hottest part of the year has passed, and water use will begin to decline as outdoor watering decreases.  Even so, water conservation now will help extend water resources until enough rain events generate meaningful recharge.

Take a moment to tune up your well and clean your pump house, fix pesky drips and leaks, dip your toes in the Blanco or stroll along Cypress Creek.  Be part of the collective solution to protect our shared water supply.

 

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:

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