Pond Boss Forums INTRO Questions & Observations Fish Over Spillway

I was wondering what usaully happens to the fish in a pond when it floods and water goes over the spillway. Do most fish swim upstream and tend to stay in the pond or do they usaully get washed downstream? If it matters what kind of fish I have:(bass, bluegill, channel cat and fatheads). I have placed a two foot high section of hardware screen across the spillway to minimize fish escape during mild floods but was wondering what would happen if this was washed away.

In California we get all of our rain in the "winter" which causes huge water flows into and out of our ponds. In my case I have a brook outflow that travels about 1/4 mile before dumping into a larger brook via a 2' diversion pipe. At the highest flows, fish getting washed over the spillway will wind up in some cases in the middle of a field hundreds of feet beyond the diversion pipe which can't handle the maximum flow. Even more remarkable is the fact that I find adult Bluegills, Bass and large numbers of baby bluegills stranded in puddles and very much alive. So, I am obliged to go fishing in my fields and return these escapes to the pond. Conversely, I have found Rainbow Trout in the brook swimming upstream. They would have to come up through the earlier mentioned diversion pipe, quite an effort. I'm sure a screen would help you, in my case they plug up quickly and create other problems at the spillway. Basically, I think fish will swim upstream if they can, some species more compelled to do so than others.

There is a method that I use that helps keep fish from completly leaving the area and is a great way to keep a supply of bait fish at reach at any time.If you can construct a small exit pond behind your spillway.It is best to construct it away from the back of the exit a little bit but can put it right behind the pipe or exit just have to line the banks with rip rap to hold the bank back.You'll want to make this about 3-4' deep and narrow enough to be able to sain fish to put back in main pond it needs to have a sharp exit ledge to help keep fish in also lined with rip rap.I like to put these in and have seen fish swim back up to these and spawn.Then you have some fish to restock or use as forage for your pond.Hope this gives you some thing you might be able to use good luck.

I would not be too concerned with fish escaping over your spillway. A few fish will escape but bass, bluegill and channel cat will not usually go over in large enough numbers to have a negative impact on the fish population. I would only worry about it if your pond is very small, like less than 1/2 acre. then a few bass will make a big difference.

Grass carp are another story. they are native to rivers and will instinctivly move into flowing water. Fish passage barriers on spillway type drains are essential to keeping grass carp in a pond. I would also consider one if trout are stocked.

if you decide to put up a barrier consult a qualified contractor or engineer. flowing water is a powerful thing. I have seen a few home made barriers destroyed after large rain events and the land owner ends up spending money again. Its best to do things once.

Shan

I agree with Shan. Quite a few Fathead Minnows will go over the spillway also. Screens inevitably clog with algae & debris. Verticle bars are usually better, but they to will clog. You need to have an overflow designed for any screen device so that when the inevitable happens, water will find its way through the spillway. Remember that most dams/dykes are designed for the current water level, and if you add another foot of water onto that, you could be creating a dangerous situation.

I agree with you Mike you should never alter the capacity of a pond or a spillway unless you are able to beef up your levy ponds that have been designed for a certain capacity should not be altered or it could cause alot of problems.But if you want to keep a few fish and keep some around to use for bait or just to put back in to the pond for forage in the fall to help with the winter then and exit pond is the way to go it can be constructed without altering the exsisting pond at anytime.I have even used these as a sorce to stock fish in other ponds that need alittle help because of a bad spawn.DOC