We have a 5 acre pond that we are looking to drop around 2 to 3 feet in order to clean out the head water as it has accumulated silt over many years. The middle of the pond is roughly 15 feet deep. I have placed the head of my pipe roughly 15 feet from the bank into the water and about 3 feet deep. The pipe then runs uphill about 155 feet to a T which is at the peak of the hill and used to pour water in to fill up the pipes. The pipe then runs downhill to the drain end 180 feet where I have it capped off until I have the pipes fill with water and ready to release in order to cause a siphon effect and pull the pond water out.
I am running into an issue on the pond side of the T. The water seems to be draining into the pond under water and not holding in the pipes. As mentioned, the pipe is underwater about 15’ out from the bank and 3’ deep. I would think that the pipes would be full of water up to that point and not capable of being pushed out because of all the water pressure in the pond. Also, I have checked for pipe leaks and there appear to be none.
Can someone please help with any suggestions on why that end of the siphon is not holding water?
