Stage 1 drought status hits numerous areas within Brazos River basin

Stage 1 drought status hits numerous areas within Brazos River basin

The Brazos River Authority, on March 18, 2022 announced the implementation of a Stage 1 – Drought Watch for several reservoirs and reservoir systems within the BRA water supply system.

The declaration comes after multiple areas throughout the basin met triggers set within tACRdata-9x16-ppt-201...he BRA Drought Contingency Plan associated with the Palmer Hydrological Drought Index (PHDI), a suite of indicators developed within the U.S. Weather Bureau.

As of March 17, 2022, 95% of the Brazos River basin – which crosses most of the physiographic regions of Texas - was experiencing a certain level of drought. Parts of the upper and central basin were experiencing exceptional drought status, the highest level on the U.S. Drought Monitor’s scale. The basin starts about 50 miles west of the Texas-New Mexico state line and stretches to the Gulf of Mexico.

The declaration comes after portions of the state reported a historic winter dry spell. John Nielsen-Gammon, Ph.D., state climatologist in the College of Geosciences Department of Atmospheric Sciences at Texas A&M University, said here that most of the state is very dry, and the rain outlook is not promising.

Reservoirs affected by the March 18 Stage 1 Drought Watch notice include Lakes Proctor, Aquilla, Belton, and Limestone. The reservoir systems affected by the declaration include the Possum Kingdom-Granbury-Whitney Reservoir System and the Georgetown-Stillhouse Hollow Reservoir System.

The PHDIis an indicator of the level of wet or dry conditions within a particular area. Due to the drier than normal conditions in the Brazos River basin, the monthly PHDI has dropped below the -2.4 trigger.  

“The PHDI is a metric that incorporates different hydrological variables, such as declining streamflow, groundwater levels, and departure from normal rainfall. This metric indicates the level of hydrological impacts of drought,” said BRA Water Services Manager Aaron Abel. “If you have wet conditions, the PHDI is positive. As a certain area dries with below normal rainfall, the PHDI becomes lower. If it goes into negative territory, that’s when you typically see the potential for drought conditions affecting water resources on longer timescales. Although our reservoirs’ levels are not significantly impacted by drought yet, the PHDI is an early warning indicator that more significant reservoir level drawdowns may occur if we continue to have below-normal rainfall.”

The stated goals of Stage 1 – Drought Watch are to raise awareness of the developing drought situation and achieve a 5% voluntary reduction of the water use that would have occurred in the absence of any drought contingency measures.

Each water contract holder that obtains supply from any of the affected reservoirs or reservoir systems is asked to:

  1. Activate their Drought Contingency Plan;
  2. Increase public education efforts on ways to reduce water use;
  3. Notify customers of actions being taken; and
  4. Any other actions they deem appropriate for your situation.

Additional information on Stage 1 – Drought Watch implementation can be found on pages 9 and 10 of the BRA Drought Contingency Plan here. Current drought information is also available here.

On March 17, the National Weather Service Weather Forecast Office in Fort Worth released information that said the outlook for the next three months favors abnormally warm and dry conditions to persist across North and Central Texas. It’s also important to note that regardless of antecedent conditions, it is typical for this region to experience river and flash flooding during the spring months as springtime thunderstorms can produce excessive rainfall with rapid runoff.

The Brazos River Authority monitors water supply and drought conditions within the basin and will notify both contract holders and the public when changes under the plan are made, or additional action is required.