Drought Management

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.

December 2018

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.

National and state drought information links
HTGCD Drought Stage History