Billions of gallons of water flow through Meander Reservoir. When just a few inches of rainfall are added, the water needs to go somewhere to prevent damage to the 3500-foot dam. 

"When you're not full, the reservoir will continue to fill up. But when you're full, it will start to exceed the capacity of the reservoir and go over the spillway," says Chief Engineer Tom Halloway. 

Close to 1.5 inches of rain fell on Thursday, adding up to around 81.5 million gallons of water,  Some of that water was discharged, causing flooding along Route 46. 

When the water in Meander Reservoir reaches a certain point it flows over the primary spillway, and the water is discharged down meander creek.

If primary spillways aren't enough, there are two auxiliary spillways to the west of the primary spillway. The auxiliaries were built in 1995, but those haven't been used since there construction.  Halloway says the reservoir has emergency plans in place if rainfall would exceed 20 inches in a 72 hour period. 

"We've had an engineering study done in regard to a breach of a dam and what kind of event would occur,  and what area would be impacted. We have mapping which has been provided that to the emergency management agencies in regard to a failure or a partial failure would occur, what would be impacted and what they would see downstream," adds Halloway.