A. Development on properties that include any portion of a foothill or hillside tributary floodplain shall provide for channel stabilization and bank stabilization or be set back from the edge of the floodplain sufficient to protect the use and floodplain from flood related erosion. Such measures shall be certified by a professional engineer licensed in the state of Idaho to be effective for the flood flows and velocities anticipated at the site as determined through the completion of an FES as set forth in subsection 8-3F-6D4 of this article.
B. Transportation routes shall not be allowed within areas determined to be floodways except as necessary to cross the floodway where no reasonable alternative exists. Bridges that cross foothill or hillside tributary floodplains shall have all horizontal bridge support members elevated to at least one foot (1') above BFE, and all supporting members shall be designed to withstand the flows and velocities of the base flood. If culverts are used, the roadway surface must be one foot (1') above the determined BFE.
C. Check dams shall be designed and certified by a professional engineer licensed in the state of Idaho and reviewed and approved by the Ada County engineer to ensure the safety of persons and property that could be affected by the construction of the check dam. An FES, as set forth in subsection 8-3F-6D4 of this article, shall be completed by a professional engineer licensed in the state of Idaho on behalf of the applicant/owner, submitted to and approved by the Ada County engineer as part of the floodplain application. (Ord. 835, 12-3-2014; Ord. 914, 6-10-2020)