Merry Christmas! I'm hoping updating this thread makes more sense than creating a new one. This summer/fall answered a lot of questions about the pond. I'll try to be as thorough and concise as I can. I had spent several days dredging the pond last spring. I believe a lot of the material I was removing was organic material like pine needles mixed with a non native grey clay layer(bentonite?) that was sitting on top of an old cracked and deteriorated liner. I remember this layer rolling up like sod, but it wasn't completely consistent and I'd estimate I only removed 4-6 cubic yards. It made a noticeable difference in how fast the pond filled/emptied. The pond stayed relatively low and was only about 6 feet at its deepest point after receiving 24,000+ gallons a day from april-october. The water was shut off mid October and the pond was completely empty by mid November which has never happened. It had supported a fish population for years... I also measured the flow rate which is definitely 24,000 gallons or more a day.
We've decided it makes sense to line the pond somehow. Still undecided on the best product. It seems like a traditional liner is prone to tearing and breaking down. I swim during the summer and don't want to worry about stepping on it and causing damage or replacing it in 10 years. We're thinking that whatever we end using to seal it, it makes sense to leave a portion of the basin top unlined so that the water seeps into the ground feeding the trees and continuing to flow(gravity fed) fresh water into it rather than equalizing when the water level reaches the input pipe. 18" seems like a good gap, but it's really hard to anticipate if that will achieve our goal of maximizing the depth without compromising water quality. The irrigation canal that feeds the pond is a service that is pretty expensive and only runs 6 months out of the year so we want to keep it flowing those months it's on.
I plan on using a string/water level to mark the circumference and keep the decided liner level consistent. If we go with a traditional liner, is it required to bury the entire thing to protect it from UV/punctures? What is the suitable trench depth/width for burying the edges?
My dad who owns the pond doesn't have the motivation or knowledge to do the job and is considering hiring a handyman who told him "he could do it". This guy is not a pond guy. It makes just as much sense for me to do it and save my dad thousands in labor costs. In my experience, especially in this area people commonly oversell therselves and misrepresent their skills/experience. Nothing against the handyman, but for all we know he has 0 experience doing ponds, and would be doing it for the money. I'm a professional rigger/carpenter with many years and certifications on heavy machinery. Not a pond guy either, but as detail oriented as anyone! I'd like to do it for my dad free of charge and make sure we get the best possible outcome. Money saved on labor can be used towards better materials available.
Thanks for any advice, I look forward to coming up with a solid plan that I can put into action in the next few months. Sorry for any repetition from my older posts, it's been a while laugh. Happy holidays!
Jesse