Pond Boss Forums AERATION Systems questions need help with outlet at dam

Great site guys, I joined a couple of years ago when I first built my pond. Now i'm looking for some info on what to do now. I originaly had just a culvrt, rocked in on top of the dam. That definitely didn't work. First spring almost lost the hole dam. So then I had to redo the dam.I have a 6 inch pipe going threw the dam 5 ft down. That pipe is ontop of untouch earth. The dam goes another 4 ft down then. the hole dam is made out of clay and below is all clay. The dam is about 9ft tall and 1o ft wide. As you can see from pics. Its been growing grass for 2 1/2 years now. I think its time to hold back some water. My Idea is to just put a 90 on the pipe and bring it up 4 1/2 feet. It would drain from the top down under dam. Is this going to work and is it about the only think I can do now at this point? At the top of the pipe should I put elbow on it. I live in western maine where we get alot of Ice and snow. Whats that going to do to the top of the pipe. My pond is 75ft wide by 150ft. I also regulate most of the water going into it. Herer's a pic of pond. the father end is the dam and the last pic is the pipe under it

I just put an AgriDrain inlet control structure on my pond, but I am only going to raise the water level maybe 18 inches. I will raise my water leve about 6 inches per year to allow my water plants to adjust. How high is your emergency spillway?

Well i guess i don't really have a emergency spill way. It would just go over the dam.

You might want to think about carving out an emergency spillway through undisturbed soil to carry flood water around the dam (constructed to leave enough freeboard on the dam to protect the dam from washing out). Once you get a good crop of grass growing in the spillway, then raise the inlet to the outlet pipe to a level a few feet under the spillway (or as far as needed depending on your drainage area into the pond). You mentioned that you regulate most of the water that goes into your pond. What do you mean by that?

My pond has two inlets. 1st is just spring run off that goes in the pond. The other is asteady flow from my well. When we driled and cap the well it would flow right out of the top at a good rate. So I piped the excess form the well to the pond. This runs constantly at a good flow.I put another valve and pipe near the pond to control that source to the pond. Right now its not going in it.What did you mean by freeboard? You said put spillway through undisturbed soil but there isn't any unditurbed soil on that end of the pond,its mostly all fill. The dam is all grass now.

By freeboard I mean the distance from the highest point in the emergency spillway to the top of the dam. You do not want water to run over the dam. The emergency spillway can be constructed at any point on the pond as long as it caries water around the dam rather than over it.