Pond Boss Forums POND CONSTRUCTION Building a dam Overflow question

My overflow on my 4 acre pond is a 4' oval drain pipe(horizontal). I have put a 5' x 8" solid cement bench top in from of the pipe this summer to raise the water level 8"(worked great). In order to have a draw down I need to bust up the cement top. My question is, I would like to make somthing to put in its place that would make the draw down easier. Would treated 2x8s work with some kind of sliding door or any other ideas that are out there....thx...CT

Why is the pipe oval? Can you buy an extension for your pipe? If so, slip on an "ell", and turn the ell upwards, then add a short piece of pipe into the upward pointing ell, and your lake will rise, and still overflow through the pipe.

That wont work for alot of reasons. The 8" rise is all Im gonna get. The oval pipe is 20' long with a 4' by 3' opening (it runs thru the high part of the dam)

Sounds like you should consider using what is commonly referred to as a "stop-log" structure. This is often used when flooding fields for waterfowl, but I don't see why it wouldn't work for you.

Basically it's a frame made of metal or concrete that is used in place of an exit pipe. The base is always made of concrete and the vertical legs are often made of channel iron. Treated lumber of the appropriate length and height is slipped into the vertical legs and pressed firmly to the concrete base. The wood will swell and prevent water from going through. So basically, you have a vertical track on each side that guides the lumber and holds it vertical. The concrete provides a flat even base. Sometimes caulk is used if the lumbar is to be in place for a long time and no water seepage is desired.

In order for this to work, you would need to prevent any water from getting to your pipe by building walls on either side of the structure. This would be a permanent modification that would be easy to take care of.

Now if you want to go low-tech, sandbags filled with clay might work.

I also guess that you are using the emergency spillway to regulate overflow, thus the 8" max rise.

No this is the regular spillway. The emergency spill is on the other end 1' higher. Do you know where, on the net, I could look a picture of this thing you are talking about? All tho the sand bag idea is good too..thx...CT

This is the best one I could find:
web page

Ignore the fish barrier portion of the pictures and discussion and instead focus on the construction of the stoplogs themselves.

This isn't a great link, but when I posted previously I couldn't find even one decent picture on the web.

Well, I did some more looking and here's some more:
here
also here

and some interesting reading from my old waterfowl habitat instructor at the University of Missouri (not to be confused with my young waterfowl habitat instructor at Southeast Missouri State University)
good stuff

Thanks abunch Fishman!