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:
1. 
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.
A. 
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.
B. 
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 Article 12.3.4 occurs with approval of the variance pursuant to Article 12.3.12.
2. 
Projects must assure that the carrying capacity of the altered or relocated watercourse is maintained.
3. 
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.
4. 
The danger to life and property due to backwater or diverted flow caused by the obstruction or use;
5. 
The danger that the obstruction or use may be swept downstream to the injury of others;
6. 
The availability of alternative locations;
7. 
The construction or alteration of the obstruction or use in such manner as to lessen the flooding danger;
8. 
The permanence of the obstruction or use;
9. 
The anticipated development in the foreseeable future of the area which may be affected by the obstruction or use;
10. 
Relevant and related permits for the project have been obtained;
11. 
Projects must conform to the additional minimum standards and provisions of this ordinance as specified for the use or artificial obstruction specified herein; and
12. 
Such other factors as are in harmony with the purposes of these regulations, the Montana Flood Plain and Floodway Management Act, and the accompanying Administrative Rules of Montana.
13. 
The safety of access to property in times of flooding for ordinary and emergency services.
(Ord. 895, 10-9-2012)
Provided that:
1. 
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;
2. 
The excavation meets all applicable laws and regulations of other local and state agencies; and
3. 
Excavated material may be processed on site but is stockpiled outside the flood plain.
(Ord. 895, 10-9-2012)
Provided that:
1. 
Crossings are designed to offer minimal obstructions to the flood flow;
2. 
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:
A. 
Bridge lower chords shall have freeboard to at least two feet above the Base Flood Elevation to help pass ice flows, the base flood discharge and any debris associated with the discharge; and
B. 
Culverts are designed to pass the base flood discharge and maintain at least two feet freeboard on the crossing surface.
3. 
If possible, normal overflow channels are preserved to allow passage of sediments to prevent aggradations;
4. 
Mid-stream supports for bridges, if necessary, have footings buried below the maximum scour depth; and
5. 
An encroachment analysis is prepared by an engineer.
(Ord. 895, 10-9-2012)
Not associated with stream crossings and bridges provided that:
1. 
The fill is the suitable fill;
2. 
Reasonable alternate transportation routes outside the floodway are not available;
3. 
The encroachment is located as far from the stream channel as possible;
4. 
The project includes mitigation of impacts to other property owners in the vicinity of the project and the natural stream function; and
5. 
An encroachment analysis is prepared by an engineer.
(Ord. 895, 10-9-2012)
Provided that:
1. 
Suspended utility transmission lines are designed such that the lowest point of the suspended line is at least six feet higher than the Base Flood Elevation;
2. 
Towers and other appurtenant structures are designed and placed to withstand and offer minimal obstruction to flood flows;
3. 
When technically feasible, the crossing will not disturb the bed and banks of the stream and alternatives such as alternative routes, directional drilling, and aerial crossings are considered; and
4. 
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.
(Ord. 895, 10-9-2012)
Provided that:
1. 
The material or equipment is not subject to major damage by flooding and is properly anchored to prevent flotation or downstream movement; and
2. 
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.
(Ord. 895, 10-9-2012)
Provided that:
1. 
They are driven or drilled wells located on ground higher than surrounding ground to assure positive drainage from the well;
2. 
They require no other structures (e.g., a well house);
3. 
Well casings are water tight to a distance of at least 25 feet below the ground surface and the well casing height shall be a minimum of 18 inches above the base flood elevation;
4. 
Water supply and electrical lines have a watertight seal where the lines enter the casing;
5. 
All pumps and electrical lines and equipment are either of the submersible type or are adequately floodproofed; and
6. 
Check valves are installed on main water lines at wells and at all building entry locations.
(Ord. 895, 10-9-2012)
Provided that:
1. 
Access roads require only limited fill and do not obstruct or divert flood waters;
2. 
Meet the accessory structures requirements;
3. 
An encroachment analysis must be prepared by an engineer;
4. 
No dwellings or permanent mobile homes are allowed;
5. 
Recreational vehicles and travel trailers are ready for highway use with wheels intact, with only quick disconnect type utilities and securing devices, and have no permanently attached additions; and
6. 
There is no large-scale clearing of riparian vegetation within 50 feet of the mean annual high water mark.
(Ord. 895, 10-9-2012)
Structures accessory to appurtenant to permitted uses such as boat docks, loading and parking areas, sheds, emergency airstrips, permanent fences crossing channels, marinas, picnic shelters and tables and lavatory, provided that:
1. 
The structures are not intended for human habitation or supportive of human habitation;
2. 
If the structures are substantial as determined by the permit issuing authority, an encroachment analysis must be prepared by an engineer;
3. 
The structures will, insofar as possible, be located on ground higher than the surrounding ground and as far from the channel as possible;
4. 
Only those wastewater disposal systems that meet the requirements and separation distances under ARM 17.36.101-116 and ARM 17.36.301-345 are allowed;
5. 
Service facilities within these structures such as electrical, heating and plumbing are floodproofed;
6. 
Structures are firmly anchored to prevent flotation;
7. 
The structures do not require fill and/or substantial excavation;
8. 
No large scale clearing of riparian vegetation within 50 feet of the mean annual high water mark; and
9. 
The structures or use cannot be changed or altered without permit approval.
(Ord. 895, 10-9-2012)
Must be designed by an engineer and constructed to withstand the flood depths, hydrodynamic and hydrostatic pressures, velocities, impact, buoyancy, and uplift forces associated with the base flood and include an encroachment analysis. The design shall also show compliance with the following additional criteria:
1. 
LEVEE AND FLOODWALL construction or alteration:
A. 
The proposed construction or alteration of a levee or floodwall must be designed and constructed with suitable fill and to safely convey a base flood;
B. 
Except to protect agricultural land only, are constructed at least 3 feet higher than the elevation of the base flood;
C. 
Unless to protect only agricultural land, protection of structures of more than one land owner requires engineering and construction to meet state and federal levee standards and be publicly owned for the purpose of construction, operation and maintenance; and
D. 
For any increase in the elevation of the base flood the following information must be provided:
i. 
The estimated cumulative effect of other reasonably anticipated future permissible uses;
ii. 
The type and amount of existing flood prone development in the affected area; and
iii. 
Impacts to existing or foreseeable development.
2. 
BANK STABILIZATION PROJECTS, PIER AND ABUTMENT PROTECTION projects if:
A. 
The materials for the project should be the least environmentally damaging and practicable designed to withstand a base flood within five years or other time as required by the Flood Plain Administrator and does not require substantial yearly maintenance after that period;
B. 
Materials for the project may be designed to erode over time but not fail catastrophically and impact others. Erosions and raveling of the materials may be designed to be at least similar in amount and rate to existing natural stream banks during the base flood;
C. 
The project must not increase erosion upstream, downstream, or adjacent to the site;
D. 
Materials for the project may include but are not limited to rip rap, root wads, brush mattresses, willow watting, woody debris or combinations of analogous materials;
E. 
The stream's biological capacity and habitat potential shall be incorporated in the project design; and
F. 
The project includes compensating efforts by replacing and providing substitute resources or environments through creation, restoration, enhancement or preservation of similar or appropriate resource areas.
3. 
CHANNELIZATION PROJECTS where the excavation and/or construction of an artificial channel is for the purpose of diverting the entire flow of a stream from its established course and provided the projects do not increase veloCity to a level that will cause erosion.
4. 
DAMS provided:
A. 
The design and construction is in accordance with the Montana Dam Safety Act and applicable safety standards; and
B. 
The project will not increase flood hazards downstream either through operational procedures or improper hydrologic/hydraulic design.
(Ord. 895, 10-9-2012)
Projects intended to reestablish the terrestrial and aquatic attributes of a natural stream and not for protection of a structure or development provided:
1. 
The project design is reviewed and approved by an engineer;
2. 
An encroachment analysis is performed by an engineer;
3. 
The project will not increase erosion upstream, downstream, or adjacent to the site;
4. 
Materials may include but are not limited to rip rap, root wads, brush mattresses, willow watting, woody debris or combinations of analogous materials;
5. 
Erosions and raveling of the materials are similar in amount and rate to existing natural stream banks during the base flood; and
6. 
The project meets the terrestrial and aquatic resource capabilities of the area.
(Ord. 895, 10-9-2012)