Drought Management
The Hays Trinity Groundwater
Conservation District has moved into 30% Curtailment Stage of groundwater
pumping in the Jacobs Well Groundwater Management Zone and 20% Curtailment Stage district wide. In order to help
ensure the health of the aquifer in the Jacobs Well Groundwater Management
Zone and its residents, please protect your aquifer by limiting water use
to indoor Covid-19 fighting uses, HTGCD Board and Staff.
New Drought Contingency Plan containing updated Rules 13 and 15 is available
here.
The HTGCD uses Pedernales and Blanco River streamflow as District-wide drought
indicators because these rivers are recharge features of our aquifers. Aquifer
recharge occurs relatively slowly, and streamflow indicates the current and
future health of the Trinity Aquifer in the District -- and therefore determines
what stage of drought we must observe.
Data shows healthy streamflow in the Perdernales River is above 31.6 cubic
feet per second (cfs), and 28.5 cfs in the Blanco River. The District recommends
conservative use of water when streamflow is healthy.
When streamflow drops below a drought trigger -- shown in the table below as
"Alarm," "Critical," and "Emergency" -- a daily counter begins. If the counter
for both drought indicators reaches 30 days, the District Board will declare the
appropriate drought stage.
To move out of a drought stage, both drought indicators must flow 60 consecutive
days above the current drought trigger in order to give aquifers time to recharge.
The declaration of the District coming out of drought stage will go into effect on
the next Board Meeting.
HTGCD Zone
Stage Start Date: September 2020
Discharge Flow Rate |
30 Day Mean |
60 Day Mean |
Alarm Trigger |
Critical Trigger |
Emergency Trigger |
Region K |
|
 |
Pedernales Rv nr Johnson City, TX (08153500) as of 2021-01-23 | 21.22 |
17.1 |
31.6 |
10.2 |
2.23 |
|
Days with flow Above Stage Trigger | |
|
0 |
38 |
60+ |
|
Days with flow Below Stage Trigger |
|
|
20 |
0 |
0 |
|
|
Region L |
|
 |
Blanco Rv at Wimberley, TX (08171000) as of 2021-01-23 |
13.79 |
13.66 |
28.5 |
14.5 |
9.28 |
|
Days with flow Above Stage Trigger |
|
|
0 |
0 |
60+ |
|
Days with flow Below Stage Trigger |
|
|
30+ |
12 |
0 |
Streamflow is measured by the United States Geological Survey (USGS) gages at the Blanco River
in Wimberley and the Pedernales River in Johnson City. These gage readings are represented by
the graphs above. The yellow triangles represent the median flow over an 80-year period and
the blue line represents streamflow in CFS. More information about the Blanco and Pedernales
River can be found by clicking the USGS symbol to the left of the name in the table above.
Jacob's Well Groundwater Management Zone Drought Management
In order to protect groundwater supplies and Jacob's Well spring flow in the 39
square mile Jacobs's Well Groundwater Management Zone, District Rule 15 designates
cutback triggers based on Jacob's Well spring flow. When flows from Jacob's Well
averages six cfs or less during any 10-day period, The District Board declares
appropriate drought stage.
Discharge Flow Rate |
30 Day Mean |
10 Day Mean |
Alarm Trigger |
Critical Trigger |
Emergency Trigger |
|
Jacob's Well Groundwater Management Zone |
|
 |
Jacobs Well Spg nr Wimberley, TX (08170990) as of 2021-01-23 |
0.86 |
0.64 |
6 |
5 |
3 |
|
|
|
|
|
|
|
|
Days with flow Below Stage Trigger |
|
|
30+ |
30+ |
30+ |
Jacob's Well Management Zone
Stage Start Date: November 2020
National and state drought information links
HTGCD Drought Stage History
For print version with graphs included,
Click here
To close graphs, Click here
Region K Drought Stage Triggers
Region L Drought Stage Triggers