(A) An alteration in this paragraph is a change to the existing boundary to the specific maps and data of the referenced studies in this section that form the basis for the regulated flood hazard area.
(B) An alteration may be the result of new data and information or when technical or scientific flood data show that the base flood elevation has or may be changed or was erroneously established and the boundaries of the regulated flood hazard area are incorrect.
(C) Any alteration must be based on reasonable hydrological certainty.
(D) Any alteration or proposed alteration of one-half feet or more in the base flood elevation requires approval of the DNRC in addition to an amendment of the adopted jurisdictional map.
(E) Any additional notices or approvals required by FEMA for the purpose of updating flood insurance rate maps of changes as a result of permitted activity that cause any change in topography by fill or changes in the base flood elevation is the responsibility of the permit applicant. The Floodplain Administer may represent any necessary approvals or endorsements by the permit authority to FEMA.
(F) The Floodplain Administrator shall maintain a record of all alterations.
(G) An alteration is not required when property located within the regulated flood hazard area is shown to be naturally above the base flood elevation.
(H) Except in a flood fringe, alteration approval from DNRC is required if property is to be raised to a level above the base flood elevation by suitable fill and where the encroachment by the fill causes a rise in the base flood elevation of more than one-half feet. No portion of the fill may be within the floodway.
(I) No alteration of a regulated flood hazard area is required when property located within the regulated flood hazard area is elevated with fill to at or above the base flood elevation and is permitted.
(J) When property located within the regulated flood hazard area is naturally above the base flood elevation as proven by a certified elevation survey provided by an engineer or land surveyor, the property owner may be required to submit a letter of map change (LOMA) to FEMA in order to affect the flood risk designation for insurance purposes. Information on the process and requirements are available through FEMA.
(K) Alteration of the floodplain usually requires FEMA approval for modification to their FEMA Insurance Rate Maps and may require preapproval by conditional letter of map revision, and/ or letter of map revision or other map change approvals in addition to approval from the Floodplain Administrator and DNRC.
(Ord. 2013-01, passed 1-30-2013)
Statutory reference:
Alteration of floodplains, see ARM 36.15.505, 36.15.505(1)(b), 36.15.505(2)
Floodway delineation, see ARM 36.15.502