This Chapter's protection standard 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, then the protection standard shall be according to the best existing data available in the Illinois State Water Survey's Floodplain Information Repository that has been approved by DNR/OWR and FEMA. 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 DNR/OWR and FEMA.
(A) The base flood or 100-year frequency flood elevation for the SFHAs of Crystal Creek, Crystal Creek Tributary, and the Des Plaines River, shall be as delineated on the 100-year flood profiles in the countywide Flood Insurance Study for Cook County prepared by the Federal Emergency Management Agency and dated August 19, 2008.
(B) 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 mile extraterritorial jurisdiction or that may be annexed into the Village shall be as delineated on the 100-year flood profiles in the countywide Flood Insurance Study for Cook County prepared by the Federal Emergency Management Agency and dated August 19, 2008.
(C) 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.
(D) 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.
(1) 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.
(2) The flood flows used in the hydraulic models shall be obtained from a hydrologic model, such as HEC-I, TR-20, or HIP, or by techniques presented in various publications prepared by the United States Geological Survey for estimating peak flood discharges.
(3) Along any water-courses draining more than one square mile, the above analyses shall be submitted to DNR/OWR for approval. Once approved it must be submitted to the Illinois State Water Survey Floodplain Information Repository for filing.
(4) For a non-riverine SFHA, the Base Flood Elevation shall be the historic Flood of Record plus three feet, unless calculated by a detailed engineering study and approved by DNR/OWR for drainage areas greater than one square mile.
(Ord. 05-2528, passed 7-26-05; Am. Ord. 08-2680, passed 5-27-08)