Look, filling in these streambeds and paving over them a century-plus ago probably seemed like a good idea at the time. Swamps were widely recognized by then as mosquito havens and malaria was a serious problem. Draining, filling, putting in proper underground storm drainage, those were all the rage circa 1910.
However. Storm drains are not always maintained properly. Land uses shift. Old memories of "there was a pond there, still is sometimes when it rains" fade. Finally, new people who Have No Idea move into town and are happy to snap up unbuilt lots at a fantastically (suspiciously?) low prices.
No matter where you're considering moving but especially so in the case of Apalachicola, do yourself a favor and look up old maps of the place, and scout out for low spots to avoid. Inset there's a map of Apalachicola dating from 1857, before these streams and marsh ponds were filled. (click to embiggen) Everywhere on the map where there's a red dot, that's where there's frequent flooding, obvious drainage problems, mold & mildew, repeated begging for special exceptions to zoning, lawsuits over midnight hauls of fill dirt, or at the very least, damp and cranky people. Notice how these spots mostly seem to fall along old streambeds or on low ground near the river or bay.
Gravity, man, it works. Water flows downhill. Don't be downhill.
