As I said earlyer the seep tube is about 4 foot under the intended water line, and the slump is 20 inches under the spillway and my question is;

What is the best way to raise the water line back to the intended level?

Do I have to have the seep tube dug out and reset, or can I fill the seep tube with concrete and put a siphon system in at the current level of the slump and level the dam off?