(A) Regulated flood hazard areas. The regulated flood hazard areas are the 100-year floodplains illustrated and referenced in the following specific studies and reports described as follows:
(1) April 15, 1986 FEMA flood insurance rate map for the city. (Attached to the ordinance codified herein as Appendix A.);
(2) The regulated flood hazard areas specifically described or illustrated in the above referenced studies and maps of the 100-year floodplain have been delineated, designated and established by order or determination by the DNRC pursuant to M.C.A. §§ 76-5-201 et seq.; and
(B) Interpretation of regulated flood hazard area boundaries.
(1) The mapped boundaries of the floodplain illustrated in the referenced studies and maps in this section are a guide for determining whether property is within the regulated flood hazard area.
(2) A determination of the outer limits and boundaries of the regulated flood hazard area or the flood fringe and floodway within the regulated flood hazard area includes an evaluation of the maps as well as the particular study data referenced in this section. Supporting study material for base flood elevations takes precedence over any map illustrations if it exists.
(3) The regulated flood hazard area boundary is delineated by the base flood elevation. The physical field regulatory boundary of the regulated flood hazard area is the actual intersection of the applicable study base flood elevation with the existing adjacent terrain of the watercourse or drainway.
(ARM 36.15.501(6))
(4) The floodway boundary where identified within the floodplain is as illustrated on the referenced maps and studies. Since the floodway boundary is a study feature, the location of the boundary may be physically located by referencing the study data to a ground feature. The Floodplain Administrator’s interpretation of the boundary and decision may be appealed as set forth in § 152.13.
(5) The Floodplain Administrator may request additional information described below to determine whether or not the proposed development is within the regulated flood hazard area.
(a) Where base flood elevations exist, the property owner may provide additional information which may include elevation information provided by an engineer or land surveyor in order to determine if the proposed development is subject to these regulations. (ARM 36.15.501(6))
(b) Where base flood elevations do not exist, the property owner may provide additional information to be considered to determine the location of the regulatory boundary or alternatively provide a computed base flood elevation provided by an engineer.
(c) The Floodplain Administrator’s interpretation of the boundaries and decision may be appealed as set forth in § 153.13.
(6) Any owner or lessee of property who believes his or her property has been inadvertently included in the regulated flood hazard area including the floodway or flood fringe may submit scientific and/or technical information to the Floodplain Administrator for a determination if the property is appropriately located. Scientific or technical information submitted to FEMA by an owner to affect the insurance rating for insurance purposes may be considered by the Floodplain Administrator. A determination by the Floodplain Administrator is independent of any determination by FEMA for insurance purposes.
(C) Alteration of regulated flood hazard area.
(1) Revisions or updates to the specific maps and data that alter the established floodplains or floodway of the regulated flood hazard area requires DNRC approval pursuant to M.C.A. § 75-5-203. An alteration of the regulated flood hazard area is a DNRC approved amendment to the DNRC order that originally delineated and designated the 100-year floodplain and is the basis of the regulated flood hazard area referenced in division (A)(2) above. A DNRC approved alteration consists of revisions or updates to the specific maps and data of the referenced studies in this section and forms the basis for an amendment to the regulated flood hazard area in these regulations;
(ARM 36.15.505)
(2) Any change to the regulated flood hazard area as a result of a DNRC alteration is effective upon amendment to the regulated flood hazard area described in division (A)(1) above;
(3) Substantial natural physical change or new technical or scientific flood data showing that the base flood elevation has or may be changed or was erroneously established shall be brought to the attention of DNRC and FEMA;
(ARM 36.15.505(1)(a)) (44 C.F.R. § 65.3)
(4) Any floodplain permit application for a proposed development or artificial obstruction must be denied until a DNRC alteration pursuant to M.C.A. § 76-5-203 is approved if it causes an increase of 0.5 feet or more to the base flood elevation of a regulated flood hazard area without a floodway or an increase of more than 0.00 feet to the base flood elevation of a floodway;
(5) To propose an alteration a petition must be submitted to DNRC and must include the following information:
(a) Certification that no buildings are located in the areas which would be impacted by the increased base flood elevation;
(44 C.F.R. § 65.12(a)(5))
(b) Evidence of notice to all property and land owners of the proposed impacts to their properties explaining the proposed impact on their property;
(44 C.F.R. § 65.12(a)(3))
(c) Information that demonstrates that alternatives are not feasible;
(44 C.F.R. § 65.12(2))
(d) Information that demonstrates that development is for a public use or benefit; and
(e) Any other supporting information and data as needed for approvals.
(ARM 36.15.505) (44 C.F.R. § 60.3(c)(10)) (44 C.F.R. § 60.3(d)(3)) (44 C.F.R. § 65.7(3)) (44 C.F.R. § 65.12))
(6) The Floodplain Administrator may represent the permit authority for any necessary applications, approvals or endorsements such as the FEMA community acknowledgment form to FEMA where affecting the FEMA special flood hazard area;
(7) A determination by the Floodplain Administrator that land areas located within the regulated flood hazard area are above the base flood elevation as proven by a certified elevation survey does not constitute or require an alteration or an amendment of the regulated flood hazard area and may be maintained as a public record that more explicitly defines the regulated flood hazard area boundary;
(8) Elevating with suitable fill as permitted does not alter the regulated flood hazard area or remove the elevated area from the regulated flood hazard area; and
(ARM 36.15.505(2))
(9) A floodplain permit implementing the physical change cannot be approved until a CLOMR has been issued by FEMA.
(Ord. 2018-01, passed 5-21-2008)