I dug a 14x14 in ground pond in FL, used an EDPM liner. I poured a concrete base, then made a 3 foot tall raised area with concrete blocks which had a preformed pond shell in the top. The water was pumped into that pond, spilled over the front and down the waterfall and part of it went down a little side stream and spilled into the pond. It was so tranquil there. I used to go out and sit and listen to the water falling for hours. I had huge koi after a while, like 2 feet long! Grew them from babies in a fish tank.
I had water hyacinth, papyrus, and iris plus palm trees . I love the jungle look. Oh and water lillies, pink and yellow ones.