12-9-2: GENERAL REQUIREMENTS:

An application for a permit shall meet the following requirements:

   A.   All projects shall be designed and constructed to ensure that they do not adversely affect the flood hazard on other properties and are reasonably safe from flooding;

   B.   All projects shall assure that the carrying capacity of the Floodway is not reduced. All projects in the Floodway shall meet the following:

      1.   Demonstrate that the project does not increase the Base Flood Elevation by conducting an encroachment analysis certified by an engineer. A minimal or qualitative encroachment analysis may be accepted when the project or development does not require a structure, alteration of the Floodway, involve fill, grading, excavation or storage of materials or equipment but is also certified by an engineer to not exceed the allowable encroachment to the Base Flood Elevation; and

      2.   The allowable encroachment to the Base Flood Elevation is 0.00 feet, and no significant increase to the velocity or flow of the stream or water course unless approval of an alteration of the Regulated Flood Hazard Area pursuant to section 12-4-3 and an approved FEMA Conditional Letter of Map Revision occurs before permit issuance ((ARM 36.15.604) (ARM 36.15.505) (ARM 36.15.605(b)) (44 CFR 60.3(a)(3 and 4)) (44CFR 65.12(a)); and

   C.   An application for a Floodplain permit must also demonstrate the following factors are considered and incorporated into the design of the use or artificial obstruction in the Floodway:

      1.   The danger to life and property due to backwater or diverted flow caused by the obstruction or use ((MCA 76-5-406(1)) (ARM 36.15.216(2)(a)));

      2.   The danger that the obstruction or use may be swept downstream to the injury of others ((MCA 76-5-406(2)) (ARM 36.15.216(2)(b)));

      3.   The availability of alternative locations ((MCA 76-5-406(3)) (ARM 36.15.216(2)(c));

      4.   Construct or alter the obstruction or use in such manner as to lessen the flooding danger ((MCA 76-5-406(4)) (ARM 36.15.216(2)(d)));

      5.   The permanence of the obstruction or use and is reasonably safe from flooding ((MCA 76-5-406(5) (ARM 36.15.216(2e)));

      6.   The anticipated development in the foreseeable future of the area which may be affected by the obstruction or use ((MCA 76-5-406(6)) (ARM 36.15.216(2f)));

      7.   Relevant and related permits for the project have been obtained (44 CFR 60.3(a)(2));

      8.   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 ((MCA 76-5-406(7)) (ARM 36.15.216(2)(g))); and

      9.   The safety of access to property in times of flooding for ordinary and emergency services (44CFR 60.22 (c)(7)). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-3: MINING OF MATERIAL REQUIRING EXCAVATION FROM PITS OR POOLS:

Provided, in addition to the requirements of section 12-9-2, that:

   A.   A buffer strip of undisturbed land of sufficient width as determined by an engineer to prevent flood flows from channeling into the excavation is left between the edge of the channel and the edge of the excavation (ARM 36.15.602(1)(a));

   B.   The excavation meets all applicable laws and regulations of other local and state agencies (ARM 36.15.602(1)(b)); and

   C.   Excavated material may be processed on site but is stockpiled outside the Floodway (ARM 36.15.602(1)(c)). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-4: RAILROAD, HIGHWAY AND STREET STREAM CROSSINGS:

Including other transportation related crossings provided, in addition to the requirements of section 12-9-2, that:

   A.   Crossings are designed to offer minimal obstructions to the flood flow (ARM 36.15.602(2));

   B.   Where failure or interruption of public transportation facilities would result in danger to public health or safety and where practicable and in consideration of FHWA Federal-Aid Policy Guide 23CFR650A:

      1.   Bridge lower chords shall have freeboard to at least two (2) feet above the Base Flood Elevation to help pass ice flows, the base flood discharge and any debris associated with the discharge; and

      2.   Culverts shall be designed to pass the Base Flood discharge and maintain at least two (2) feet freeboard on the crossing surface;

   C.   Normal overflow channels, if possible are preserved to allow passage of sediments to prevent aggradations; and

   D.   Mid stream supports for bridges, if necessary, have footings buried below the maximum scour depth. (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-5: LIMITED FILLING FOR ROAD AND RAILROAD EMBANKMENTS:

Including other transportation related embankments not associated with stream crossings and bridges provided, in addition to the requirements of section 12-9-2, that:

   A..   The fill is suitable fill;

   B.   Reasonable alternate transportation routes outside the floodway are not available (ARM 36.15.602(3)); and

   C.   The encroachment is located as far from the stream channel as possible (ARM 36.15.602(3)). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-6: BURIED OR SUSPENDED UTILITY TRANSMISSION LINES:

Provided, in addition to the requirements of section 12-9-2, that:

   A.   Suspended utility transmission lines are designed such that the lowest point of the suspended line is at least six (6) feet higher than the Base Flood Elevation (ARM 36.15.602(4));

   B.   Towers and other appurtenant structures are designed and placed to withstand and offer minimal obstruction to flood flows (ARM 36.15.602(4));

   C.   Alternatives such as alternative routes, directional drilling, and aerial crossings are considered when technically feasible; and

   D.   Utility transmission lines carrying toxic or flammable materials are buried to a depth of at least twice the calculated maximum scour depth determined by an engineer for the Base Flood (ARM 36.15.602(4)). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-7: STORAGE OF MATERIALS AND EQUIPMENT:

Provided, in addition to the requirements of section 12-9-2, that:

   A.   The material or equipment is not subject to major damage by flooding and is properly anchored to prevent flotation or downstream movement (ARM 36.15.602(5)(a)); or

   B.   The material or equipment is readily removable within the limited time available after flood warning. Storage of flammable, toxic or explosive materials shall not be permitted (ARM 36.15.602(5)(b)). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)

12-9-8: DOMESTIC WATER SUPPLY WELLS:

Provided, in addition to the requirements of section 12-9-2, that:

   A.   They are driven or drilled wells located on ground higher than surrounding ground to assure positive drainage from the well (ARM 36.15.602(6));

   B.   They require no other structures (e.g. a well house) (ARM 36.15.602(6));

   C.   Well casings are water tight to a distance of at least twenty five (25) feet below the ground surface and the well casing height is a minimum of two (2) feet above the base flood elevation or capped with a watertight seal and vented two (2) feet above the base flood elevation ((ARM 36.15.602(6)));

   D.   Water supply lines have a watertight seal where the lines enter the casing (ARM 36.15.602(6));

   E.   All pumps and electrical lines and equipment are either of the submersible type or are adequately flood proofed (ARM 36.15.602(6)); and.

   F.   Check valves are installed on main water lines at wells and at all building entry locations ((44 CFR 60.3 (a)(5)) (ARM 36.15.602(6))). (Ord. 16-3, 11-7-2016; amd. Ord. 16-3, 12-19-2022)