It depends on how well the house is serving you now, and if it is a primary residence, secondary, or a rental.

If the only problem is that you anticipate problems, keep it, keep living in it until there are signs that actual problems are looming – like major moves in the foundation that make it dangerous to live in. Did a foundation contractor tell you there are foundation problems to scare you into a big project ? Or a trusted engineer? Or did you see a crack in the slab and panic ?Big difference.

Maybe get an appraisal on the house. Don’t tell them about the foundation issues. Just determine the value of the place if it were structurally sound after a major foundation reinforcement project.

Then determine the cost to make it all better. Ask an engineer (recommend Bruce Cosart) what they think needs to be done, maybe employ a geo-technical engineer as well. I’d want to measure the movement. Maybe have a surveyor take measurements every 6 months. If the slab is cracked and there is no movement for a couple of years, maybe all is good. If an engineer and geo-engineer look at each other and say “holy shit” then you have work to do and decisions to make.

Once you know the scope of the problem, the cost to fix it, and the utility of the house to you, then you can make some decisions. If it is safe to live in but unsellable, keep it forever.

How old is the Riverbed?

If the riverbed is more than 99 years old, it’s one thing, if the riverbed is dry the last 10 years it’s another.

Also why did the river dry up? Have industries pumped it dry or did snowpack go away?

Consult a hydrological engineer and see if you can get flood insurance.