I have a 3/4 acre stream-fed pond which has had major problems with the overflow spillway over the last 7 years. The original spillway was eroding, so we attempted to have a new one cut into the bank, but shortly afterwards, the old spillway partially blew out after 13" of rain in 4 days. The old spillway was filled in again, but the new spillway never really handled the overflow adequately - it just was not cut into the bank low enough to take the water and instead, the water gradually eroded the soil at the original spillway. There is a good stretch of rip rap in the new spillway - 50'x 10' but it sits up too high and is barely being used.
With the recent hard rains during the last several weeks, the original spillway has opened up and now has continuous flow; the pond level is nearly 6" below the vertical drainage pipe in the pond. To compound the problem, the overflow floods across the gravel driveway because the 2 24" drainage pipes are not enough to handle the volume of water in a flood. I've lost a portion of the driveway as a result. The excavator that did the work the first 2 times didn't get it right, so someone else is scheduled to do the repair work. Any suggestions as to how to best address the spillway design and the drainage issues?? We're looking at: building up the bank at the outlet so the water level rises to original level; widening the spillway to 10'-12' -to include the original and new spillways; cutting into the bank so that the spillway level will take water across entire stretch; and adding at least 1 more 24" pipe under the driveway to accommodate the volume during floods. What do folks think of these proposed solutions? Do any of these ideas sound like they'll adequately address the problems? Any suggestions would be greatly appreciated.
