There is space and it's not hilly
Space? For how many runways?
How many runways do you want?
There's lots of lovely green fields just waiting for the concrete - build four runways to start with.
Reserve the space for two more, call it car parking, warehouse space - anything that is cheap to tear down ... whatever happens don't use the space for housing or as prime office space and always declare that runways will be built there so the nimbys cant complain when the build starts