Flood · Glossary
Floodway
Updated 2026-07-20
A floodway is the channel of a river plus adjacent areas that must be kept free of encroachment to convey the base flood without raising water surface levels beyond a designated amount.
What it means
A floodway is the channel of a river plus adjacent areas that must be kept free of encroachment to convey the base flood without raising water surface levels beyond a designated amount.
Why it matters for land decisions
Confirm how the concept applies to your specific parcel with the city or county planning department and the controlling agency map or ordinance.
- Treat online GIS as a first-pass screen.
- Verify before design, escrow, or lending decisions.
People also ask
What is Floodway?
A floodway is the channel of a river plus adjacent areas that must be kept free of encroachment to convey the base flood without raising water surface levels beyond a designated amount.
Is a GIS overlay enough to decide?
No. Public GIS is a screening tool. Official determinations come from the governing agency, recorded documents, and licensed professionals when required.
Official sources
Related terms
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