It would be hard to figure out the costs, of-course any construction project has many variables. Assuming that you already own the land, the liner is going to be around 45,000$. The construction costs will be ~1,000$ per day, so based on the magnitude of the project that's what your looking at. In the USA anyway.
Austin MK 1000 per day. not a bad guess. once they get measurements on how much soil needed moving, that's a HUGE part of the project price. also, to build up the embankment they need soil. they may had to import dirt in to build the embankment. once they figure that out, that's another cost. one thing for sure...it ain't cheap.
I guess the dam finished in 10 days by 10 workers each 150 dollar per day as labour cost. And some 3 trucks once bulldozer. Each cost 200 per day. 23 k, and bringing the soil, I assume you have the soil, and that black membrane would off course cost you some 50 k on that vast area, so you would have some hidden costs so think from 100 k to 150 you would need. 😁 I don't live in USA but I think so the project would cost something like that