Floodgates at the Denison Dam are open as Lake Texoma and the surrounding region continues to reel from record rainfall in September and prepare as another wet weekend approaches.


U.S. Army Corps of Engineers Assistant Lake Texoma Manager Tommy Holder said the floodgates will remain open, 24-hours a day until the agency’s efforts make an impact on flooding, which Holder said has led to numerous campground and boat ramp closures. As of Wednesday afternoon, Holder said the lake’s surface stood at an elevation of just over 621 feet. The Denison Dam’s uncontrolled spillway begins at an elevation of 640 feet and the top of the dam peaks at 670 feet.


“The lake has risen roughly about four feet,” Holder said. “So, we’re currently releasing about 15,325 cubic feet of water per second.”


The National Weather Service reports the Sherman-area received 10.51 inches of rainfall in September and the month now ranks as one of Texas’ five wettest on record. An additional 2.95 inches of rain has fallen on Sherman since the start of October and NWS Meteorologist Jason Godwin of the agency’s Fort Worth field office said the frequent and heavy rains that have fallen across the region are the result of larger weather patterns at play.


“We’ve seen a lot of it come from tropical cyclones in the eastern Pacific that have recurved up into Mexico and the Southwest,” Godwin said. “We’ve had moisture from those make it into our area and that has combined with a more active weather pattern that’s typical for the fall.”


Though Sherman’s totals speak to the amount of rainfall received locally, Holder said the drainage basin surrounding Lake Texoma is expansive and has collected the runoff from many other hard hit locations.


“The watershed for Lake Texoma is about equivalent in size to the state of Indiana,” Holder said. “That’s about 39,700 square miles.”


And Godwin said long-range forecasts indicate much of the south-central U.S., including Lake Texoma’s watershed, is likely to see higher than usual rainfall throughout the autumn and winter months, thanks to a familiar and reoccurring, warming pattern.


“The Climate Prediction Center, which is part of the National Weather Service, they put out an El Niño watch, thinking there’s a reasonable chance we could go into that pattern,” Godwin said. “And if that’s in fact the case, that tends to result in a wetter-than-normal winter for the Southern Plains, including here in North Texas.”


With the runoff of recent rains still making its way to Lake Texoma, Holder said it was likely that waters would continue to rise and possible that officials would begin to release even greater volumes of water in the days and weeks ahead. An additional one to two inches of rain are predicted to fall across the region this weekend, but Holder said he and the U.S. Army Corps of Engineers will take stock of the lake’s status each day and adjust accordingly.


“We don’t manage water until it’s on the ground,” Holder said. “But with that said, we’re always mindful of the weather and the forecast.”