"Floodway" means the stream channel plus that portion of the overbanks that must be kept free from encroachment in order to discharge the one percent annual chance flood without increasing flood levels by more than one foot, which is adopted into a local floodplain management ordinance.

Source. (See Revision Note #1 and Revision Note #2 at chapter heading for Env-Wq 1600) #13944, eff 4-27-24