(A)   Purpose.
      (1)   The purpose of this district is to protect and preserve the natural and scenic resources of bluffs and steep slopes.
      (2)   These resources represent an enhancement to the community and if left unprotected, risk impairment to the health, safety, tax base and general welfare of the community and natural ecological functioning of the local environment.
   (B)   Scope, interpretation and application.
      (1)   The provisions of this section shall apply to all lands located within the Bluff Protection District, within the corporate limits of the City, and are delineated on the official zoning map of the City.
      (2)   Where the provisions of this chapter or any other ordinance are in conflict, the more restrictive regulations shall take precedence.
   (C)   Permitted uses. Permitted uses in the overlay district include all permitted and accessory uses allowed in the underlying zoning district, unless listed as a conditional or prohibited use in this chapter.
   (D)   Conditional uses.
      (1)   All uses considered conditional uses in the underlying zoning district shall be considered conditional uses under this chapter, unless prohibited by this or other applicable ordinances;
      (2)   Campgrounds;
      (3)   Utility transmission lines; and
      (4)   Infrastructure owned and constructed by the City.
   (E)   Prohibited uses.
      (1)   Sand and gravel extraction;
      (2)   Commercial manufacturing of sand and gravel by-products;
      (3)   Junkyards;
      (4)   Downhill ski areas;
      (5)   Cemeteries; and
      (6)   All other uses not authorized in the underlying zoning district.
   (F)   District dimensional requirements.
      (1)   The following chart sets forth the minimum area, setbacks and other requirements of the Bluff Protection District.
All Lots
Building setback from top of bluff
100 feet
Building setback from toe of bluff
25 feet
Maximum lot area covered by impervious surface measured to the centerline of the road
Vegetative cutting area setback from top of bluff
50 feet
      (2)   No structures shall be placed or result in grading on any slope equal to or greater than 12% as measured over a 50-foot distance.
   (G)   General performance standards.
      (1)   The exterior color of new or renovated structures, including roofs, shall be of earth or summer vegetation tones, unless completely screened from Highway 3.
      (2)   No land shall be subdivided which is determined by the City to be unsuitable by reason of flooding, inadequate drainage, soil and rock formations with severe limitations for development, severe erosion potential, unfavorable topography, inadequate water supply or any other features likely to be harmful to the health, safety or welfare of the future residents of the proposed subdivision or the community. Soil borings shall be required in any proposed subdivision within the Bluff Protection District, to establish the suitability of the land for development. The testing is required before any preliminary plat may be approved, but may be waived by the Zoning Administrator when adequate data is already available.
      (3)   Existing drainage patterns shall not be disturbed except by public rights-of-way or easements which cross drainage patterns in a general perpendicular direction.
   (H)   Grading and erosion control standards. Grading, filling, excavating or otherwise changing the topography shall not be conducted without a grading permit from the Zoning Administrator. A grading permit may be issued only if:
      (1)   Slopes equal to or greater than 12% are not affected;
      (2)   No more than one-third of the surface of the development area shall be devoid of vegetative ground cover at any time;
      (3)   Temporary ground cover such as mulch shall be used and permanent cover such as sod shall be planted as soon as possible;
      (4)   An erosion control plan to prevent erosion and trap sediment shall be employed in accordance with regulations of the state’s Pollution Control Agency and approved by the City Engineer;
      (5)   Fill is stabilized according to accepted engineering standards;
      (6)   Alternations to topography do not adversely affect adjacent or nearby properties;
      (7)   Site design that minimizes vegetation removal and slope alteration; and
      (8)   Clear cutting of vegetation is prohibited, except to remove the minimum amount of vegetation necessary for placing roads, trails, utilities, structures and parking areas.
   (I)   Vegetation removal performance standards. On slopes of 12% or greater (measured over a 50-foot distance), there shall be no vegetative cutting of live trees or shrubs without a vegetative cutting permit from the Zoning Administrator. A permit may be issued under the following conditions:
      (1)   The cutting, including topping, involves trees less than four inches DBH (diameter at breast height as measured at 54 inches above the ground);
      (2)   The cutting, including topping, involves vegetation which is not screening any structure from view from Highway 3;
      (3)   The essential character, quality and density of existing growth is preserved and continuous canopy cover is maintained;
      (4)   Removal of dead or diseased trees;
      (5)   The cutting is necessary for the maintenance of transportation or utility rights-of-way; and
      (6)   A vegetative cutting permit is not required for the following; provided, the existing quality, character, density and canopy is maintained as viewed from Highway 3:
         (a)   Clearing for a validly permitted structures, roadways and parking areas; and
         (b)   Maintenance, trimming or pruning located within a transportation or utility right-of-way.
   (J)   Stairway and lift standards. All stairways and lifts on bluffs shall be visually inconspicuous. Stairways and lifts are the preferred alternatives to major topographic alterations for achieving access up and down bluffs and steep slopes. Stairways, lifts and landings shall meet the following design requirements.
      (1)   Stairways and lifts must not exceed four feet in width on residential lots. Wider stairways may be used for public open space uses.
      (2)   Landings for stairways and lifts must not exceed 32 square feet in area. Landings larger than 32 square feet may be used for public open space uses.
      (3)   Canopies or roofs are not permitted in stairways, lifts or landings.
      (4)   Stairways, lifts and landings may be either constructed on posts or pilings, or placed into the ground; provided, they are designed in a manner that ensures control of soil erosion.
      (5)   Stairways, lifts and landings shall be located in the most visually inconspicuous portion of lots, as viewed from adjacent areas, assuming summer, leaf-on conditions.
   (K)   Conservation design - planned unit developments. A pattern of subdivision development which places dwelling units into compact groupings is encouraged when the proposed grouping provides a better means of preserving open space, natural hydrological functioning, woods, scenic views and other natural features than the application of the standard dimensional requirements. Exceptions to impervious surface and setback requirements may be allowed for planned unit developments that provide significant public and environmental benefits as described in the City’s PUD ordinance.
(Ord. passed 3-20-2002, § 19)