For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
100-YEAR FLOOD. One percent annual chance flood. See BASE FLOOD.
ALTERATION. Any change or addition to an artificial obstruction that either increases its external dimensions or increases its potential flood hazard (ARM §36.15.101(2)).
APPURTENANT STRUCTURE. A structure in which the use is incidental or accessory to the use of a principal structure (44 C.F.R. §59.1).
ARTIFICIAL OBSTRUCTION. Any obstruction which is not natural and includes any development, dam, diversion, wall, riprap, embankment, levee, dike, pile, abutment, projection, revetment, excavation, channel rectification, road, bridge, conduit, culvert, building, refuse, automobile body, fill, or other analogous structure or matter in, along, across or projecting into any regulated flood hazard area that may impede, retard or change the direction of the flow of water, either in itself or by catching or collecting debris carried by the water, or that is placed where the natural flow of the water would carry the same downstream to the damage or detriment of either life or property. See also DEVELOPMENT (ARM §36.15.101(3)).
BASE FLOOD (FLOOD OF 100-YEAR FREQUENCY). A flood having a 1% chance of being equaled or exceeded in any given year (ARM §36.15.101(4); 44 C.F.R. §59.1).
BASE FLOOD ELEVATION (BFE). The elevation above sea level of the base flood in relation to the National Geodic Vertical Datum of 1929 or the North American Vertical.
BASEMENT. Any area of a building, except a crawlspace, as having its lowest floor below ground level on all sides (44 C.F.R. §59.1; NFIP Insurance Manual, Rev. October 2021).
BUILDING. A walled and roofed structure, including a gas or liquid storage tank that is principally above ground, as well as a manufactured home (44 C.F.R. §59.1).
CHANNEL. The geographical area within either the natural or artificial banks of a watercourse or drain way.
CONDITIONAL LETTER OF MAP REVISION (CLOMR). A FEMA letter of approval for a proposed physical change that when completed would propose to change the flood zones, delineation or elevations on the FEMA flood insurance rate map or FEMA flood boundary map, and may amend the FEMA flood insurance study through a subsequent LOMR. The CLOMR may be considered in an evaluation by DNRC and the Floodplain Administrator during consideration of a proposed alteration to the regulated flood hazard area.
CRAWLSPACE. An enclosure that has its interior floor area no more than five feet below the top of the next highest floor. See ENCLOSURE and SUBGRADE CRAWLSPACE (NFIP Insurance Manual, Rev. October 2021).
DNRC. Montana Department of Natural Resources and Conservation.
DEVELOPMENT. Any human-made change to improved or unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations, or storage of equipment or materials. See also ARTIFICIAL OBSTRUCTION (44 C.F.R. §59.1).
ELEVATED BUILDING. A building that has no basement and that has it lowest elevated floor raised above ground level by foundation walls, shear walls, posts, piers, pilings or columns. A building on a crawlspace is considered an ELEVATED BUILDING (NFIP Insurance Manual, Rev. October 2021).
ENCLOSURE. The portion below the lowest elevated floor of an elevated building that is either partially or fully shut in by rigid walls, including a crawlspace, subgrade crawlspace, stairwell, elevator or a garage below or attached.
ENCROACHMENT. Activities or construction within the regulated flood hazard area, including fill, new construction, substantial improvements and other development.
ENCROACHMENT ANALYSIS. A hydrologic and hydraulic analysis performed by an engineer to assess the effects of the proposed artificial obstruction or non-conforming use on base flood elevation, flood flows and flood velocities.
ESTABLISH. To construct, place, insert or excavate (ARM §36.15.101(9)).
EXISTING ARTIFICIAL OBSTRUCTION or NON-CONFORMING USE. An artificial obstruction or non-conforming use that was established before land use regulations were adopted pursuant to MCA §76-5-301(1).
FEMA. The Federal Emergency Management Agency.
FLOOD FRINGE. The identified portion of the floodplain of the regulated flood hazard area outside the limits of the floodway (ARM §36.15.101(10)).
FLOOD OF 100-YEAR FREQUENCY (BASE FLOOD). A flood magnitude expected to recur on the average of once every 100-years or a flood magnitude that has a 1% chance of occurring in any given year (44 C.F.R. §59.1).
FLOOD PROOFING. Any combination of structural and non-structural additions, changes or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, electrical, plumbing, HVAC systems, structures and their contents. The term includes wet flood proofing, dry flood proofing and elevation of structures (44 C.F.R. §59.1).
FLOODPLAIN. The area of the regulated flood hazard area including and adjoining the watercourse or drainway that would be covered by the floodwater of a base flood. The area is partitioned into a flood fringe and floodway where specifically designated. See REGULATED FLOOD HAZARD AREA.
FLOODPLAIN ADMINISTRATOR. Community official or representative appointed to administer and implement the provisions of this chapter.
FLOODWAY. The identified portion of the floodplain of the regulated flood hazard area that is the channel and the area adjoining the channel that is reasonably required to carry the discharge of the base flood without cumulatively increasing the water surface by more than one-half foot.
LETTER OF MAP CHANGE (LOMC). An official response from FEMA that amends or revises the FEMA special flood hazard area and FEMA flood insurance study for flood insurance purposes and/or flood risk hazard. FEMA LETTERS OF MAP CHANGE specific to an amendment or revision include:
(1) LETTER OF MAP AMENDMENT (LOMA). A letter of determination from FEMA issued in response to a request that a property or structure is not subject to the mandatory flood insurance requirement because it was inadvertently located in the effective FEMA special flood hazard area. The material submitted and response from FEMA may be considered by the Floodplain Administrator for determining if a property or structure is within the regulated flood hazard area and subject to these regulations.
(2) LETTER OF MAP REVISION BASED ON FILL (LOMR-F). A letter of approval from FEMA removing the mandatory requirement for flood insurance on property based on placement of fill or an addition. Placement of fill or an addition must be preceded by a permit pursuant to these regulations. Placement of fill does not remove the development from the regulated flood hazard area or these regulations.
(3) LETTER OF MAP REVISION (LOMR). An official FEMA amendment to the currently effective FEMA flood insurance rate map or FEMA flood boundary map based on a physical change to the floodplain of the special flood hazard area. It is issued by FEMA and changes flood zones, delineations and elevations on the FEMA flood insurance rate map or FEMA flood boundary map and may amend the FEMA flood insurance study. It must be preceded by an approved alteration of the designated floodplain from DNRC and subsequently an amendment to the regulated flood hazard area.
LOWEST FLOOR. Any floor of a building, including a basement used for living purposes, storage or recreation. This includes any floor that could be converted to such a use (ARM §36.15.101(14); 44 C.F.R. §59.1).
MANUFACTURED HOME PARK OR SUBDIVISION. Includes the construction of facilities for servicing the manufactured home lots and at a minimum, includes the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads (44 C.F.R. §59.1).
MANUFACTURED OR MOBILE HOME. A building that may be residential or non-residential, is transportable in one or more sections, built on a permanent chassis and designed to be used with or without a permanent foundation when connected to the required utilities and includes park trailers, travel trailers and other similar vehicles placed on a site for greater than 180 consecutive days (ARM §36.15.101(15)).
NEW CONSTRUCTION. Structures for which the commencement of clearing, grading, filling or excavating to prepare a site for construction occurs on or after the effective date of these regulations and includes any subsequent improvements to such structures (ARM §36.15.101(20); 44 C.F.R. §59.1).
NEW MANUFACTURED HOME PARK OR SUBDIVISION. A manufactured home park or subdivision for which the construction of facilities for servicing the lots on which the manufactured homes are to be affixed includes, at a minimum, the installation of utilities, the construction of streets and either final site grading or the pouring of concrete pads, and is completed on or after the effective date of floodplain management regulations adopted by a community (44 C.F.R. §59.1).
NON-RESIDENTIAL. Buildings, including manufactured homes that are not residential, including commercial, agricultural, industrial buildings and accessory buildings. See RESIDENTIAL.
OWNER. Any person who has dominion over, control of or title to an artificial obstruction.
PERSON. Includes any individual, or group of individuals, corporation, partnership, association or any other entity, including state and local governments and agencies (44 C.F.R. §59.1).
RECREATIONAL VEHICLE. A park trailer, travel trailer or other similar vehicle which is:
(1) Built on a single chassis;
(2) Four hundred square feet or less when measured at the largest horizontal projections;
(3) Designed to be self-propelled or permanently towable by a motorized vehicle; and
(4) Designed primarily for use as temporary living quarters for recreation, camping, travel or seasonal use, not for use as a permanent dwelling (44 C.F.R. §59.1).
REGULATED FLOOD HAZARD AREA. A floodplain whose limits have been designated pursuant to MCA Title 76, Chapter 5, Part 2, and is determined to be the area adjoining the watercourse that would be covered by the floodwater of a base flood. The REGULATED FLOOD HAZARD AREA consists of the floodway and flood fringe where specifically designated (ARM §36-15-101(11)).
RESIDENTIAL BUILDING. A dwelling or building for living purposes or place of assembly or permanent use by human beings and including any mixed use of residential and non-residential use. All other buildings are non-residential.
RIPRAP. Stone, rocks, concrete blocks or analogous materials that are placed along the bed or banks of a watercourse or drainway for the purpose of preventing or alleviating erosion (ARM §36.15.101(18)).
SCOUR DEPTH. The maximum depth of streambed scour caused by erosive forces of the base flood.
SPECIAL FLOOD HAZARD AREA. Land area which has been specifically identified by the Federal Emergency Management Agency as the floodplain within a community subject to a 1% or greater chance of flooding in any given year. It is useful for the purposes of identifying flood hazards by local subdivisions of government for regulatory purposes, as well as use by the national flood insurance program for establishing risk zones and flood insurance premium rates. The FEMA flood hazard area zone designation or flood risk potential is as illustrated on FEMA’s flood hazard boundary map or flood insurance rate map.
STRUCTURE. Any artificial obstruction.
SUBGRADE CRAWLSPACE. A crawlspace foundation enclosure that has its interior floor no more than five feet below the top of the next higher floor and no more than two feet below the lowest adjacent grade on all sides. A foundation exceeding either dimension is a basement (NFIP Insurance Manual, Rev. October 2021).
SUBSTANTIAL DAMAGE. Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would exceed 50% of the market value of the structure before the damage occurred (C.F.R. §59.1).
SUBSTANTIAL IMPROVEMENT. Any repair, reconstruction or improvement of a structure where the cost equals or exceeds 50% of the market value of the structure, either before the improvement or repair is started or if the structure has been damaged, and is being restored, before the damage occurred.
(1) Substantial improvement is considered to occur when the first construction of any wall, ceiling, floor or other structural part of the building commences.
(2) The term does not include:
(a) Any project for improvement of a structure to comply with existing state or local health, sanitary or safety code specifications which are solely necessary to assure safe living conditions; or
(b) Any alteration of a structure listed on the national register of historic places or state inventory of historic places (ARM §36.15.101(21); 44 C.F.R. §59.1)).
SUITABLE FILL. Fill material which is stable, compacted, well graded and pervious, not adversely affected by water and frost, devoid of trash or similar foreign matter, tree stumps or other organic material; and is fitting for the purpose of supporting the intended use and/or permanent structure (ARM § 36.15.101(22)).
VARIANCE. A grant or relief from the development requirements of these regulations which would permit construction in a manner that would be otherwise prohibited by these regulations by an approval pursuant §§11.06.120.010 through 11.06.120.060 (ARM §36.15.101(23)).
VIOLATION. A finding and order pursuant to the regulations against the owner or responsible party of the failure of a structure or other development to be fully compliant with these regulations (44 C.F.R. §59.1).
(Prior Code, § 11.06.020.010) (Ord. 6, passed 3-16-1981; Ord. 2021-15, passed 12-20-2021)
Statutory reference:
Artificial obstruction, see MCA § 76-5-103(1)
Channel, see MCA § 76-5-103(2)
Establish, see MCA § 76-5-103(7)
Existing artificial obstruction or non-conforming use, see MCA § 76-5-404(3)
Flood of 100-year frequency (base flood), see MCA § 76-5-103(9)
Floodway, see MCA § 76-5-103(5) and (11)
Owner, see MCA § 76-5-103(13)
Regulated flood hazard area, see MCA §§ 76-5-103(4) and (10)