What matters for project planning
Two parts of this record reach a deck and one does not. Inside a mapped flood hazard area, the flood damage prevention ordinance can govern whether and how a structure may be placed, which makes flood status a siting question best answered before design rather than after. The karst warning is the second and it is about what the footings will find: irregular underground drainage and sinkhole potential mean the ground under one post may differ from the ground under its neighbor, and that is worth establishing rather than assuming. Routine stormwater requirements mostly do not apply to a deck, since it adds little impervious surface -- though on a sloping lot the grading around it can.
Official sources
Verify the property, not just the city
None of this citywide detail can confirm your parcel's flood status, whether karst or bedrock sits close to the surface, or what's hidden in the existing structure. Check those specifics with the city or county and your chosen provider before scope is finalized.
Sources reviewed 2026-07-20. External requirements and maps can change.