A. The protection standard of this chapter is based on the flood insurance study for the village. If a base flood elevation or 100-year frequency flood elevation is not available for a particular site, the protection standard shall be according to the best existing data available in the Illinois state water survey's floodplain information repository. When a party disagrees with the best available data, he or she may finance the detailed engineering study needed to replace existing data with better data and submit it to IDNR/OWR and FEMA.
B. The base flood or 100-year frequency flood elevation for the SFHAs of the Des Plaines River and Salt Creek shall be delineated on the 100-year flood profiles in the countywide flood insurance study for Cook County prepared by FEMA and dated November 6, 2000, and such amendments to such studies and maps as may be prepared from time to time.
C. The base flood or 100-year frequency flood elevation for the SFHAs of those parts of unincorporated Cook County that are within the one and one-half (11/2) mile extraterritorial jurisdiction of the village or that may be annexed into the village shall be as delineated on the 100-year profiles in the countywide flood insurance study for Cook County prepared by FEMA and dated November 6, 2000, and such amendments or revisions to such studies and maps as may be prepared from time to time.
D. The base flood or 100-year frequency flood elevation for each SFHA delineated as an AH zone or AO zone shall be that elevation (or depth) delineated on the flood insurance rate map of the village.
E. The base flood or 100-year frequency flood elevation for each of the remaining SFHAs delineated as an A zone on the flood insurance rate map of the village shall be according to the best existing data available in the Illinois state water survey floodplain information repository. When no base flood or 100-year frequency flood elevation exists, the base flood or 100-year frequency flood elevation for a riverine SFHA shall be determined from a backwater model, such as HEC-II, WSP-2 or a dynamic model such as HIP. The flood flows used in the hydraulic models shall be obtained from a hydrologic model such as HEC-1, TR-20 or HIP or by techniques presented in various publications prepared by the United States geological survey for estimating peak flood discharges. Flood flows should be based on anticipated future land use conditions in the watershed, as determined from adopted local and regional land use plans. Along any watercourses draining more than one square mile, the above analysis shall be submitted to IDNR/OWR for approval, and once approved, must be submitted to the Illinois state water survey floodplain information repository for filing. For a nonriverine SFHA, the base flood elevation shall be the historic flood of record, plus three feet (3'), unless calculated by a detailed engineering study and approved by the IDNR/OWR for drainage areas greater than one square mile. (1965 Code § 7-18-6)