An application for a permit must demonstrate the following goals and criteria are considered and incorporated into the design of any use or artificial obstruction in the floodway requiring a permit.
(A) All projects in the floodway where specifically required herein as requiring an encroachment analysis, must undergo a thorough hydrologic and hydraulic analysis prepared by an engineer to demonstrate their effect on flood flows, velocities and the base flood elevation.
(B) A conditional approval from FEMA of any proposed increase of more than zero (0.00) feet in the base flood elevation must accompany the application. An application for a FEMA conditional letter of map revision approval requires a supporting encroachment analysis.
(C) The maximum allowable increase to the base flood elevation is one-half foot (0.50), unless approval of an alteration of the regulated flood hazard area pursuant to §§ 11-1-45 through 11-1-47 of this chapter occurs with approval of the variance pursuant to §§ 11-1-130 through 11-1-135 of this chapter:
(1) Projects must assure that the carrying capacity of the altered or relocated watercourse is maintained;
(2) Projects must be designed and constructed to ensure that they do not increase the flood hazard on other properties and be reasonably safe from flooding;
(3) The danger to life and property due to backwater or diverted flow caused by the obstruction or use;
(4) The danger that the obstruction or use may be swept downstream to the injury of others;
(5) The availability of alternative locations;
(6) The construction or alteration of the obstruction or use in such manner as to lessen the flooding danger;
(7) The permanence of the obstruction or use;
(8) The anticipated development in the foreseeable future of the area which may be affected by the obstruction or use;
(9) Relevant and related permits for the project have been obtained;
(10) Projects must conform to the additional minimum standards and provisions of this chapter as specified for the use or artificial obstruction specified herein;
(11) Such other factors as are in harmony with the purposes of these regulations, the Montana Floodplain and Floodway Management Act and the accompanying Administrative Rules of Montana; and
(12) The safety of access to property in times of flooding for ordinary and emergency services is subject to other more stringent regulations.
(Ord. 2013-01, passed 1-30-2013)
Federal law reference:
Encroachments and community considerations, see 44 C.F.R. § 60.3
Planning considerations for flood-prone areas, see 44 C.F.R. § 60.22
Revision of flood insurance maps, see 44 C.F.R. § 65.12
Statutory reference:
Alteration of floodplains, see ARM 36.15.505
Minimum criteria for permits, see ARM 36.15.604
Permit criteria, see ARM 36.15.216(2)
Prohibited uses, see ARM 36.15.605(b)
Variance request considerations, see MCA 76-5-406