How are the floodplain zones (AE, AO and X) reflected on the maps defined?
The flood zones are defined as follows: Zone AE: Areas where 100-year flows are hydraulically connected to the South Boulder Creek mainstream or other conveyance paths with a hydraulic gradient will be designated as Zone AE. All areas of flooding in excess of 3″, regardless of hydraulic connectivity or gradient will be designated as Zone AE. BFEs will be reported for all the areas designated within Zone AE. NOTE: Given the +/- 0.5-foot accuracy of the one-foot contour interval mapping, the AE boundary will be determined where the computed depth is equal to or greater than one foot (when rounded to the nearest one foot). Zone AO: Areas where 100-year flows have a computed depth (when rounded to the nearest one foot) equal to or greater than one foot that do not meet the criteria established for Zone AE will be designated as Zone AO. This will generally include ponded and shallow flow areas between 1′ and 3′ deep. Zone X-shaded: Areas where 100-year flows do not meet the criteria establi
