The Nemaha County Sheriff's Office announced Thursday a dam located one mile south of Sabetha is in danger of failing, but Nemaha County emergency manager Russel Lierz said failure isn't certain.
"It's releasing water but not a complete failure at this time," Lierz said late Thursday afternoon. "We don't know when exactly it will fail and how much will be released between now and the failure. We feel there is a possibility of it failing but we are not an imminent threat."
Lierz said the dam has been releasing water since Tuesday morning and water level is currently about 35 feet.
"There's a large hole on the back side of the dam, so at this time we don't have a crystal ball to look in," Lierz said. "We just can't predict exactly what it's going to do."
The large hole will not be repaired until more water drains, Lierz said.
The alert was posted on the sheriff's office Facebook page and said the possible dam failure would cause flash flooding downstream on the Delaware River.
Locations that would impacted if the dam fails are US-36 highway, the Kickapoo Indian Reservation and Golden Eagle Casino.
"Best-case scenario if it does break, it does a slow release is what we are hoping," Lierz said.
Water could rise to about 13.8 feet at US-36 highway approximately one hour after dam failure, the alert said.
Dam failure could also cause water to rise about 11.2 feet at US-75 highway about three hours after.
The National Weather Service issued a flash flood warning for the areas of east-central Nemaha County, northeast Jackson County and southwest Brown County.