River managers and forecasters are watching where the rain falls Monday to decide how to adjust dam releases and who needs to be warned of what's coming.
Monday morning the National Weather Service River Forecast Center predicted minor to moderate flooding across parts of northeast Oklahoma. But if heavier rainfall cells shift the flooding could occur in other areas or be worse than expected.
Forecasts for minor to moderate flooding this afternoon or Tuesday morning were predicted at several locations, including Polecat Creek at Sapulpa, Bird Creek at Sperry and Avant, and Caney Creek at Collinsville, Ramona and Bartlesville.
“We’ll have to keep an eye on it because there will be some isolated heavier amounts in some places so it could go even higher than forecast in some areas,” said hydrologist Eric Jones with the River Forecasting Center in Tulsa. “This is our best forecast of where the rain will fall but it may shift to the north, south, east or west, and that may shift the water level from one basin to another.”
Minor flooding is categorized as having water outside the channel of a creek or river that may cause inconveniences. Moderate flooding may close some roads and encroach on people’s property. Flooding is considered major at the point it begins entering homes, building and closing major roads, he said.
The forecast for the Arkansas River at Tulsa will continue to depend most heavily on U.S. Army Corps of Engineers releases from Keystone Dam, which decreased significantly over the weekend.
Keystone Lake dropped 2 feet since Saturday and continues to fall as flow into the lake dropped by nearly 30 percent and releases from dam were cut back from 80,000 to 60,000 cubic feet per second early Monday.
The Arkansas River at Tulsa dropped nearly 2 feet in that same period, from 12.9 feet to 11 feet. The river was at its high point six days ago at 14.49 feet, when the Corps announced it was nearing “regulation stage,” which is 15 feet.
U.S. Army Corps of Engineers spokesman Preston Chasteen said operations at the reservoirs will remain steady until after the expected rains and adjustments will be made at that time.
"For right now we just have to wait and see," he said.
Minor flooding is forecast on the Arkansas River at Muskogee. The river was at 27.11 feet early Monday but is forecast to rise to minor flooding level at 1 a.m. Tuesday at 27.9 feet with a crest near 30 feet late Tuesday. The river at Muskogee has been near or above its “regulation stage” of 27 feet since May 4.
Other Northeast Oklahoma rivers with minor flooding forecasts include the Neosho River at Commerce and the Illinois River at Tahlequah.