§ 160.27 BUFFER YARDS.
   (A)   Purpose, application and use. It shall be recognized that the creation of zoning districts does not in itself sufficiently protect persons and properties from possible harm or detrimental influences that are or may be present on an adjoining property, and that the special buffer yards as set forth in this section are necessary to more fully achieve the purposes and intent of this Code. A buffer yard shall consist of a setback together with plant materials and may also be required to include a berm, fence, wall or combination thereof according to the requirements of this Code. Use thereof shall be restricted to landscaped open space to create and maintain a necessary transition and physical barrier between contrasting land uses. Each buffer yard setback shall be designed, constructed and perpetually maintained with plantings, topography and fences, walls or other barriers to screen, separate and eliminate or substantially mitigate existing or potential nuisances such as dirt, litter, noise, glare of lights, odor, intrusion of privacy, danger from fires or explosions, and other adverse influences.
   (B)   Location and use. Buffer yards shall be located on the entire common perimeter of the contrasting uses, and extend to the lot lines. No part of any buffer yard shall be used for any building or other structure, parking, storage, display, loading, active recreation, as a location for refuse containers, or for any other use or activity which may create a nuisance or be otherwise detrimental to the adjoining property.
   (C)   Provision of buffer yard. Buffer yards shall be provided and maintained in accordance with the following.
      (1)   (a)   If adjoining properties in different zoning districts were improved prior to the enactment of buffer yard requirements, any existing partial or total noncompliance with the buffer yard requirements of this section shall be deemed a legal nonconformity. Should a buffer yard be desired where a conforming buffer does not exist, or if the buffer yard requirements are increased because of a zoning change or other amendment to this Code, or other reason, the establishment or increase of a buffer shall be by mutual agreement between property owners, by conditions of rezoning, or as otherwise provided by law. However, if an existing improved property is redeveloped, the legal nonconformity for that portion of such property being redeveloped shall be considered to be extinguished, and the land to be vacant land and subject to the buffer requirements.
         (b)   If a buffer yard exists all or in part, even if not required at the time of initial development, it shall not be reduced or otherwise modified in a manner that creates or increases nonconformity with this Code.
      (2)   New nonresidential developments shall be responsible for providing and maintaining buffer yards adjacent to existing or planned residential development.
   (D)   Buffer yard design options.
      (1)   Any of the following buffer yard options may be utilized, unless a specific requirement is established by agreement with neighboring property owners; is required by the Board of Adjustment for a conditional use; or is required by the City Council as a condition of zoning or site plan approval. Buffer areas shall be seeded or sodded with turf grass, planted with other approved ground cover, or satisfactorily mulched.
      (2)   No buffer yard shall be less than ten feet in width.
      (3)   An existing buffer yard shall not at any time be eliminated or reduced to a lower standard except after public hearing and approval by the City Council in accordance with the procedures for a rezoning, and a finding that conditions have changed to such extent that they can be satisfactorily mitigated by lesser, alternative measures. For the purposes hereof, option (a) of (4) and (5) shall be considered to be a lower standard than option (b), and likewise option (b) to be a lower standard than option (c) by reason of greater circulation control, noise attenuation, reduced maintenance, and other mitigation.
      (4)   Buffer yards shall be provided by churches and other religious organizations located in the “A-2,” “R-1L,” “R-1I,” “R-1S,” “R-3” and “R-4” Districts, commercial “O-R” uses, and properties zoned “C-O,” “C-N” or “C-G” that adjoin properties zoned for any residential use, and properties zoned “C-H” that adjoin any properties zoned “O-R”, in accordance with any one or approved combination of the following options:
         (a)   A buffer yard of 26 feet or more in width; and nine coniferous overstory trees, ten understory trees and 20 shrubs for each 100 lineal feet;
         (b)   A buffer yard of 25 feet or less in width; a five-foot high earth berm or six-foot high opaque wood fence; and three overstory trees, six understory trees and nine shrubs for each 100 lineal feet; or
         (c)   A six-foot high masonry wall, to be designed with face brick, stucco or similar finished surface facing towards the residential district.
      (5)   Buffer yards shall be provided by properties zoned “C-H”, “M-1” or “M-2” that adjoin properties zoned for any residential use, in accordance with any one or approved combination of the following options:
         (a)   A buffer yard 35 feet or more in width; four-foot high earth berm or opaque wood fence; and four deciduous overstory trees, six understory trees, six coniferous overstory trees and 15 shrubs for each 100 lineal feet;
         (b)   A buffer yard with a minimum width of 25 feet; five-foot high earth berm or six-foot high opaque wood fence; and nine coniferous trees, ten understory trees and 20 shrubs for each 100 lineal feet; or
         (c)   A six-foot high masonry wall, to be designed with face brick, stucco or similar finished surface facing towards the residential district; and six coniferous trees for each 100 lineal feet.
   (E)   Buffer yard exceptions and substitutions.
      (1)   Blank wall. Berms or fences otherwise required need not extend along the building, and planting requirements may be reduced by 10%, if the building is designed to have no windows, or entrances other than minimum required emergency exits, and does not have any other potential source of noise, light, hazard or other nuisance orienting onto or affecting the buffer yard; provided that this shall not be construed to reduce buffer requirements along parking or loading areas and similar areas of activity.
      (2)   Existing trees. Existing trees that satisfy the landscaping requirements of this section may be counted toward satisfying such requirements on a one to one ratio, except that oaks, maples, lindens, and similar high quality trees with a diameter of four inches or more, measured at a height of four feet, may be credited at a ratio of two existing trees for three required.
      (3)   Coniferous species. Coniferous trees or shrubs may be substituted without limitation for deciduous material.
      (4)   Solar access. Where solar access is required to be protected on an adjoining property, understory trees may be substituted for overstory trees where overstory trees would destroy such access.
   (F)   Minimum size and distribution.
      (1)   Buffer yards shall be designed, and plant material distributed, in the manner that the Department of Community Development deems to be the most appropriate for the protection of adjoining properties. Consideration may be given to topography, prevention of prohibited use of the buffer area, preservation of solar access, privacy and similar considerations.
      (2)   (a)   Plant materials shall not be pruned or otherwise prevented from growing to sufficient size to perform the intended purpose, and shall be so sized at planting to provide the desired buffering within a reasonable time period.
         (b)   Generally, overstory trees shall be eight feet or taller; understory and coniferous trees five feet or taller; and shrubs 18 inches or taller when planted.
      (3)   Plant materials shall be properly branched, and shall be of such type as may be approved by the Department of Community Development. Balled in burlap or container stock is preferred, and a maintenance bond shall be provided for a period of one year to guarantee survival of bare-root stock. Performance bonds may also be required in the event buffers have not been completed prior to occupancy.
      (4)   Buffer yards shall be properly maintained so as to satisfy the intended purpose in perpetuity.
   (G)   Contractual reduction. Where desired, the owner of an existing residence may waive any or all right to protection by buffers required of a proposed commercial development, or to substitute such alternative provisions as may be agreeable to all parties, including the City Council. Such agreement will be kept on file with the city, and may be recorded if deemed appropriate.