I have a question (actually many) about the feasibility of building (DIY) a waterfall and pond in the area pictured below. Hopefully you can read the dimensions and estimating about 3' deep. My initial thought is to have two 8wide shoulders stairsteped 8" to anchor the liner. This would only give me around 23" wide chanel, If need be I could get another 16" by sawing it off the patio as chalk marked. I am retired so I have the time but this would be my first attempt at a project like this and my skills, plumbing - electrical, are basic at best. I would appreciate any feedback you might have.