Then move out of the city to another area and forbid the building of new structures is the answer. Just move the population 10 miles or more away to a non sinking area over the next 100 years the ones closest to the low areas first then proceed from there. Don't allow businesses to expand in the affected areas and tell insurance companies they cannot insure buildings that are in the sinking area for structural damage so the businesses will move since they will not stay if they cannot have insurance and banks will not loan non insured buildings since they want to protect their investments. People will move when the businesses that need workers move and renters will move where the jobs are and parents will move to protect their kids if they are able. Sure it's expensive but it's going to be a lost cause either way if the sinking keeps up.