LAKE WHITNEY, TEXAS -- The last measurable rain may have fallen on Monday evening, but water pouring into the lake from swollen creeks and rivers continues to contribute to a steady rise in the level of the lake. As of 11:00 am Thursday, the lake level was 541.26, or 8.26 over the normal level of 533. The historical rate of rise for the previous 24 hour period was 1.97 feet. That rate of increase has slowed a bit from yesterday's 2.04, even with lowered releases from the Whitney dam.
In the days leading up to Memorial Day, lake officials were releasing hefty amounts at the dam, averaging well over 10,000 cubic feet per second pouring into the Brazos below the dam. Late on Tuesday, the outflow was reduced to almost zero. That rose a bit on Wednesday and Thursday morning, with releases currently showing at 457 cubic feet per second, which is minuscule.
Mid-day Wednesday, the Corps closed the majority of its public recreation facilities. Lake Whitney State Park also closed on Wednesday. Social media lit up soon after with reports of the lake being "closed." That description is technically incorrect. The lake is not off-limits or closed. Private facilities, like lakeside resorts, typically remain open and individuals with boats that are accessible (either in private docks or in the marinas) may still take them out on the lake.
Releases upriver pouring in
Releases from dams upriver have varied according to local rainfall amounts. On Wednesday, the nearest dam to Whitney, Lake Granbury, was releasing 26,000 cubic feet per second at one point but averaged 23,000 cubic feet most of the day. Today's releases are a more moderate 15,000 CF/S.
It takes roughly three days for water released from Granbury to reach Whitney. Above Granbury, Possum Kingdom Lake increased its outflow today to more than 16,000 CF/S, which means Granbury will again need to increase output to maintain its near-constant level. Both Possum Kingdom and Granbury are managed entirely by the Brazos River Authority.
As long as the releases from the Whitney dam are minimal, even without further rainfall, the rise in the water will continue, as water flows down the Brazos from the upper two lakes. A steady rate of near two feet per 24 hours is possible, even as the lake reaches areas where the water can spread farther into low-lying areas.
In 2016, when the lake hit its highest water levels in the last decade, the water rose from 19 feet over normal to 28 feet over normal in just four days. And at those levels, the water has a lot of space to spread out, meaning it takes a lot more water to create a two-foot per day rise.
What the lake can hold
At the current lake level, the flood pool is still only 16% full according to the Corps of Engineers. Since its construction, the highest water level the lake has seen was in 1957, when it reached near the top of the flood pool at 570.25 feet of elevation. Since that time, the highest water level was in 1990, when it reached 564.89, more than 31 feet over normal.
Read more about the history of Lake Whitney here:
Receive notifications of local news with the News Break app. Download it here.