Get a piece of corrogated plastic drain pipe 4 inches bigger in diameter and place it over your 10 inch pipe. Allow the corrogated Pipe to go down into the water 6 to 8 feet or whatever depth you can go down, your water will now discharge from the bottom.Make sure you have several inches above your 10 inch pipe so that when you lake rises it cant go over the top. You gain several benifits, you are discharging water that is low in oxygen from near the bottom and when you begin to fertilize you are not loosing fertile water as you will on a top discharge. Dont worry about the pipe getting cloged because your water is comming from the bottom of the pond. To adjust how far down the corrogated pipe goes down on you drain get 2 threaded rods and place them thru the corrogated pipe and allow these to set on top of your 10 inch pipe. I have this on my pond and it works great.

Jake