Me personally I chose to spend my money on the water source first since I knew that was a 100% way to keep the pond full. I later rewoorked at my pace. I went this route because there was no 100% way to know if I would stop the leaks. It has paid off because the first rework did not stop the leaks and I was also able to have a water source during the drought.
I do not know if you are interested or not but there is a big 3 day construction and farming auction coming up Jan 31 thru Feb 2 in Dothan Al.. The auction generally has a good bit of Irrigation and piping in it. I have picked up a good bit up metal & pvc pipe there over the years for a good price. The last couple of years I have bid live internet bidding thru proxibid after going down going down and looking at what I might want. http://www.deancoauction.com/auctions.html
