(A) Floodways (riverine). Located within SFHAs, established in § 155.07
, are areas designated as floodways. The floodway is an extremely hazardous area due to the velocity of floodwaters, which carry debris, potential projectiles, and has erosion potential. Under the provisions of the Flood Control Act (IC 14-28-1) a permit for construction in a floodway from the Indiana Department of Natural Resources is required prior to the issuance of a local building permit for any excavation, deposit, construction, or obstruction activity located in the floodway. This includes land preparation activities such as filling, grading, clearing, and paving undertaken before the actual start of construction of the structure. General licenses and exemptions to the requirements of the Flood Control Act (IC 14-28-1 and 312 IAC 10) may apply to qualified additions/improvements to existing lawful residential structures, rural bridges, logjam removals, wetland restoration, utility line crossings, outfall projects, creek rock removal, and prospecting.
(1) If the site is in a regulatory floodway as established in § 155.07, the Floodplain Administrator shall require the applicant to forward the application, along with all pertinent plans and specifications, to the Indiana Department of Natural Resources and apply for approval for construction in a floodway, provided the activity does not qualify for a general license or exemption.
(2) No action shall be taken by the Floodplain Administrator until approval has been granted by the Indiana Department of Natural Resources for construction in the floodway, or evidence provided by an applicant that the development meets specified criteria to qualify for a general license or exemption to the requirement of the Flood Control Act. The floodplain development permit shall meet the provisions contained in this subchapter.
(3) The floodplain development permit cannot be less restrictive than an approval issued for construction in a floodway issued by the Indiana Department of Natural Resources, or the specified criteria used to qualify for a general license or exemption to the Flood Control Act for a specific site/project. However, a community's more restrictive regulations (if any) shall take precedence.
(4) In floodway areas identified on the FIRM, development shall cause no increase in flood levels during the occurrence of the base flood discharge without first obtaining a conditional letter of map revision and meeting requirements of § 155.24(A). A conditional letter of map revision cannot be issued for development that would cause an increase in flood levels affecting a structure and such development should not be permitted.
(5) In floodway areas identified by the Indiana Department of Natural Resources through detailed or approximate studies but not yet identified on the effective FIRM as floodway areas, the total cumulative effect of the proposed development, when combined with all other existing and anticipated development, shall not adversely affect the efficiency of, or unduly restrict the capacity of the floodway. This adverse effect is defined as an increase in the elevation of the regulatory flood of at least fifteen-hundredths of a foot as determined by comparing the regulatory flood elevation under the project condition to that under the natural or pre-floodway condition as proven with hydraulic analyses.
(6) For all projects involving channel modifications or fill (including levees) the city shall submit the data and request that the Federal Emergency Management Agency revise the regulatory flood data per mapping standard regulations found at 44 CFR § 65.12.
(B) Fringe (riverine). If the site is in the fringe (either identified on the FIRM or identified by the Indiana Department of Natural Resources through detailed or approximate studies and not identified on a FIRM), the Floodplain Administrator may issue the local floodplain development permit provided the provisions contained in this subchapter have been met.
(C) SFHAs without established base flood elevation and/or floodways/fringes (riverine).
(1) Drainage area upstream of the site is greater than one square mile:
(a) If the site is in an identified floodplain where the limits of the floodway and fringe have not yet been determined, and the drainage area upstream of the site is greater than one square mile, the Floodplain Administrator shall require the applicant to forward the application, along with all pertinent plans and specifications, to the Indiana Department of Natural Resources for review and comment.
(b) No action shall be taken by the Floodplain Administrator until written approval from the Indiana Department of Natural Resources (approval for construction in a floodway, letter of authorization, or evidence of general license qualification) or a floodplain analysis/regulatory assessment citing the 1% annual chance flood elevation and the recommended flood protection grade has been received from the Indiana Department of Natural Resources.
(c) Once the Floodplain Administrator has received the proper written approval, evidence of general license qualification, or floodplain analysis/ regulatory assessment approving the proposed development from the Indiana Department of Natural Resources, a floodplain development permit may be issued, provided the conditions of the floodplain development permit are not less restrictive than the conditions received from the Indiana Department of Natural Resources and the provisions contained in this section have been met.
(2) Drainage area upstream of the site is less than one square mile:
(a) If the site is in an identified floodplain where the limits of the floodway and fringe have not yet been determined and the drainage area upstream of the site is less than one square mile, the Floodplain Administrator shall require the applicant to provide an engineering analysis showing the limits of the floodplain and 1% annual chance flood elevation for the site.
(b) Upon receipt, the Floodplain Administrator may issue the local floodplain development permit, provided the provisions contained in this subchapter have been met.
(D) SFHAs not identified on a map.
(1) If a proposed development site is near a waterway with no SFHA identified on a map, the Floodplain Administrator shall verify the drainage area upstream of the site. If the drainage area upstream of the site is verified as being greater than one square mile, the Floodplain Administrator shall require the applicant to forward the application, along with all pertinent plans and specifications, to the Indiana Department of Natural Resources for review and comment.
(2) No action shall be taken by the Floodplain Administrator until written approval from the Indiana Department of Natural Resources (approval for construction in a floodway, letter of authorization, or evidence of general license qualification) or a floodplain analysis/regulatory assessment citing the 1% annual chance flood elevation and the recommended flood protection grade has been received from the Indiana Department of Natural Resources.
(3) Once the Floodplain Administrator has received the proper written approval, evidence of general license qualification, or floodplain analysis/regulatory assessment approving the proposed development from the Indiana Department of Natural Resources, a floodplain development permit may be issued, provided the conditions of the floodplain development permit are not less restrictive than the conditions received from the Indiana Department of Natural Resources and the provisions contained in this subchapter have been met.
(Ord. 3-2024, passed 3-4-2024)
Statutory reference:
Similar provisions, see IC 14-28-1 or 312 IAC 10