A. Purpose And Intent: This section is intended to provide for the orderly and reasonable use of hillside areas while protecting the public health, safety and welfare by accomplishing the following:
1. Soil Conditions: Steer development to locations that have stable soil and utilize appropriate engineering techniques that accommodate the natural site conditions.
2. Maintain Natural Conditions: Minimize alterations to natural hillsides to maintain significant landforms and natural drainage patterns.
3. Intensity: Permit an intensity of development compatible with the natural characteristics of hillside terrain.
4. Public Services: Promote cost effective public services by encouraging development in less steeply sloped areas and ensuring adequate access for emergency vehicles.
5. Safety: Protect the public from unsafe development and property damage by ensuring that hillside development is reasonably located and properly constructed. Minor and isolated slope variations occurring over a run of ten feet (10') or less are exempt.
B. Applicability: This section shall apply to all development on slopes steeper than eight percent (8%) except development occurring on minor and isolated slope variations in which the slope may be steeper than eight percent (8%) for a run of ten feet (10') or less.
C. Grading And Filling:
1. Amount Of Grading Permitted: The percentage of the site that can be graded and/or filled shall be determined by the slope of the site, with more grading allowed on less steep slopes. The amount of coverage and grading permitted is established below.
PERCENT LOT COVERAGE, GRADING
AND FILL ALLOWED ON SLOPES
Coverage | Fill/Grade | ||
Slope | Percent Coverage Allowed | Slope | Percent Grading Allowed |
0 - 15% | n/a | 0 - 15% | 70 |
15.1 - 20% | 15 | 15.1 - 20% | 50 |
20.1 - 25% | 10 | 20.1 - 25% | 30 |
>25% | 0 | >25% | 0 |
Minor and isolated slope variations occurring over a run of 10 feet or less are exempt | |||
2. Ungraded Area: The undeveloped portion of the site that is not graded or filled shall be maintained in an undisturbed state with natural grade and vegetation.
D. Lot Coverage:
1. Amount Of Coverage Permitted: The percentage of the site that can be covered with impermeable surfaces is determined by the slope of the site, with more lot coverage allowed on less steep slopes. The amount of lot coverage permitted is established in this section.
2. Uncovered Area: The portion of the site that is not covered with impervious surfaces shall be revegetated with native landscaping materials to minimize erosion and stabilize slopes. At a minimum, the density of vegetation shall approximate the density of vegetation that existed in the pre-construction state.
E. Cuts And Fills:
1. Maximum Grade: The slope of a cut or fill grade shall not exceed two to one (2:1) or fifty percent (50%) to allow revegetation.
2. Setback: The toe of a fill slope, or top of a cut or fill slope shall be set back from the property line at least one-half (1/2) the height of the cut or fill slope.
3. Toe Of Natural Slope: Cutting the toe of a natural slope is prohibited.
F. Drainage: Natural drainage channels shall be preserved.
G. Soils: Development shall not be located on unstable soils. The Zoning Administrator may require a geotechnical study to determine the stability of soils. (Ord. 567, 3-20-2017)
H. Retaining Walls/Fencing: Retaining walls shall not exceed the height of eight feet (8'). More than one retaining wall in a terraced arrangement shall be permitted. Retaining walls lower than three feet (3') designed and constructed to retain earth are exempt from other standards of this title that regulate walls. Walls taller than three feet (3') are required to be permitted and must include a stamp from a licensed Montana engineer.
Fences in Residential Zones (R - Zones) shall not exceed six feet (6') in height above natural grade. The use of barbed wire or electric fences in Residential Zones is prohibited.
Fences in Business Zones (numbered B and C Zones) shall not exceed six feet (6') in height above natural grade. The use of barbed wire or electric fences in Business Zones is prohibited.
Fences in Manufacturing Zones (CLM and M-I) shall not exceed eight feet (8') in height above natural grade. The use of barbed wire is allowed in Manufacturing Zones. The use of electric fences is prohibited in Manufacturing Zones. (Ord. 570, 2-2-2018)