Due to the episodic nature of natural flood events and the resulting changes to hydrologic and hydraulic conditions along the watercourses within the county, base flood peak discharges, flow volumes, and associated regulatory floodplain and erosion hazard areas are subject to continuous revision. At a minimum, base flood values and base flood elevations will meet or exceed the current values established by the NFIP and reflect historic flood information and general, current, watershed conditions. When flood events occur that alter floodplain and erosion hazard conditions, the Chief Engineer may recommend modifications of floodplain management regulations for adoption by the Board and by FEMA.
The chief engineer will maintain current regulatory floodplain and erosion hazard area maps for the Santa Cruz River, Rillito Creek, and other major watercourses as necessary.
A. The regulatory floodplains and floodways for the Santa Cruz River, Canada del Oro Wash, Tanque Verde Creek, Agua Caliente Wash, Pantano Wash, San Pedro River, Rincon Creek, Cienega Creek, Lee Moore Wash, Brawley Wash, Black Wash, Rillito Creek, and all other major watercourses, shall be based upon flood insurance study flood hazard boundary maps or, where such maps are not available, the best available technical data and floodplain maps, as prepared by the District or by an Arizona registered civil engineer, and approved by the Chief Engineer. As flood repair and flood control improvements are constructed, the Chief Engineer will prepare revised floodplain maps for the purpose of regulation.
B. All watersheds that generate flood peak discharges exceeding five thousand cfs for the base flood discharge shall have their flood peak discharges listed by the chief engineer. These discharges will be amended, if necessary, as revised base flood discharge estimates become available.
(Ord. 2010-FC5 § 1 (part), 2010; Ord. 2005 FC-2 § 2 (part), 2005; Ord. 1999 FC-1 § 1 (part), 1999; Ord. 1988 FC-2 Art. 6 (A) (2), 1988)