Drought Deepens Across Texoma as Lake Texoma Slips Below Conservation Pool

Cooke County was entirely in moderate drought on the U.S. Drought Monitor map valid Aug. 18, two Oklahoma counties on the north side of Texoma had dropped into severe drought, and Lake Texoma sat just under the top of its conservation pool on Friday, according to Water Data for Texas and the U.S. Army Corps of Engineers Tulsa District.

The change came fast. The Drought Monitor showed Cooke County with no drought at all on July 28. Three weeks later the whole county was in the moderate category.

NOAA and National Weather Service precipitation grids showed no measured rain at the Gainesville sample point over the last 10 days or the last 30. Sampled cells at Sherman, Durant and Marietta each came back at 0.00 inches in the 10-day product. A normal August in Gainesville brings close to 2.8 inches, by the weather service's climatology for the city.

Conditions were more severe on the Oklahoma side of Texoma. The Aug. 18 map placed roughly a third of Marshall County and about 15 percent of Love County in severe drought, the second of the Monitor's four categories. Neither county carried any severe drought on the Aug. 11 map. Most of Grayson County was in moderate drought, with no severe drought in Grayson or Cooke. State totals ran the same direction: Oklahoma stood at about 62 percent in severe drought or worse, against roughly 14 percent in Texas.

Water Data for Texas listed Lake Texoma at 99.6 percent full Friday, its most recent instantaneous reading less than two inches under the 617-foot conservation pool elevation. The lake's mean level has fallen better than a foot and a half since July 21. The Corps' Tulsa District logged the same elevation at 8 a.m. Friday, about a tenth of a foot below normal. Nearby Ray Roberts Lake was around 97 percent full after standing full a month earlier.

The Drought Monitor's weekly summary attributed the dry stretch to high pressure over the southern United States, which held precipitation off the southern Great Plains during the week ending with the Aug. 18 map. The weather service office in Norman said Friday's showers would be light and give little drought relief, and that hot, dry weather would raise fire-weather conditions from late in the weekend into early next week across western Oklahoma and western North Texas. The Climate Prediction Center's seasonal outlook reported one-to-three-class worsening across the North Central and South Central Plains and anticipated drought persisting in parts of the Southern Great Plains.

The verified sources for this report show water-supply planning risk rather than a documented current municipal outage. Region C, the state water planning region that takes in Cooke and Grayson counties, defines a water need as the shortage that appears when drought pushes demand past existing supply, and projects dry-year regional demand growing by more than half between 2030 and 2080. The region says supply, conservation and reuse decisions have to be made now to guard against future droughts. Denison's own conservation plan claims rights to tens of thousands of acre-feet a year from Lake Texoma and names the lake as a main municipal source.