18.65.360 Streams and shorelines – Standard buffers.
(1) Streams and Shorelines – Buffers. No development may take place within a stream or shoreline water body or within the following standard buffer areas except as allowed within this chapter or the SMP (Chapter 16.05 CMC). Buffer widths shall be measured outward on a horizontal plane from the ordinary high water line or top of bank if ordinary high water line cannot be identified:
(a) If the stream or shoreline buffer does not include a steep slope hazard area or landslide hazard area:
(i) A Type S water body (shoreline) buffer is as defined in the shoreline master program (SMP) (Table 16.05.280-2 CMC);
(ii) A Type F stream buffer is 115 feet;
(iii) A Type Np stream buffer is 60 feet; and
(iv) A Type Ns stream buffer is 30 feet;
(b) If the stream or shoreline buffer does include a steep slope hazard area or landslide hazard area, the buffer width is the greater of either the buffer in this section, or the SMP, or 25 feet beyond the top of the hazard area; and
(c) The stream or shoreline buffer includes the entire mapped severe channel migration hazard area plus the appropriate stream buffer required by this section measured from the outer edge of the severe channel migration hazard area.
(2) Buffer Averaging. The Director may approve a modification of the minimum required standard buffer widths, on a case-by-case basis, by averaging buffer widths, based on review of a critical area report prepared by a qualified professional describing the current function of the stream and the stream buffer and the measures that will be taken to ensure that there is no loss of stream function due to buffer averaging if:
(a) The Director determines that the ecological structure and function of the buffer after averaging is equivalent to or greater than the structure and function before averaging;
(b) The resulting buffer meets the following standards:
(i) The total area of the buffer after averaging is equivalent to or greater than the area of the buffer before averaging;
(ii) The additional buffer is contiguous with the standard buffer;
(iii) Averaging does not occur waterward of the top of the associated steep slopes or into a channel migration zone; and
(iv) Averaging does not occur into the buffer of a wetland except as otherwise allowed;
(c) In no case shall a standard average stream buffer be reduced to less than 60 percent of the standard buffer in any location;
(d) Averaging does not result in any impact to another critical area;
(e) Averaging does not result in a significant adverse impact to habitat associated with species of local importance; and
(f) Buffer averaging within a shoreline jurisdiction shall also be subject to the City’s SMP regulations as set forth in CMC 16.05.280(2)(c).
(3) Buffer Reduction. The Director may approve a modification of the minimum required buffer width for a development proposal if the applicant demonstrates that the buffer cannot provide certain functions because of soils, geology or topography subject to the following:
(a) The Director shall establish the buffer width based on the ecological functions that the buffer can provide based on soils, geology and topography;
(b) The buffer widths established in accordance with this subsection are not further modified as provided for in subsection (2) of this section; and
(c) Within shoreline jurisdiction, stream and Pipe Lake shoreline buffer reductions and mitigation are implemented pursuant to CMC 16.05.230(3) and 16.05.280(2)(c).
(4) Where a legally established street transects a stream buffer, the Director may approve a modification of the minimum required buffer width to the edge of the roadway if the part of the buffer on the other side of the roadway:
(a) Does not provide additional protection of the proposed development or the stream;
(b) Does not perform any biological, geological or hydrological buffer functions relating to the undisturbed portions of the stream buffer;
(c) The alterations allowed in CMC 18.65.050 are not allowed in buffers established in accordance with this subsection; and
(d) The buffer widths established in accordance with this subsection are not further modified as provided for in subsections (2) and (3) of this section.
(5) The Director may establish minimum buffer widths for streams that are created as a result of enhancement or restoration projects that are not mitigation for a development proposal or alteration.
(6) The buffer areas established by this section do not apply to any segment of a stream that is presently within a culvert, unless that stream will be taken out of the culvert as part of development of the subject property.
(7) Permanently Altered Buffer. The Director may provide written approval for a buffer reduction when existing conditions are such that portions of the required buffer exist in a permanently altered state (e.g., roadways, paved parking lots, and permanent structures) and do not provide any buffer function, based on review of a critical area report prepared by a qualified professional. The buffer may be reduced up to the area where the altered conditions exist.
(8) Increased Buffer Widths. The Director may require increased buffer widths that are necessary to protect habitat, health, safety, and welfare on site-specific areas as follows:
(a) When the Director determines that the buffer width is insufficient to prevent habitat degradation;
(b) When a channel migration zone is present. The stream buffer width shall be measured from the outer edge of the channel migration zone; or
(c) When the stream buffer area is within an erosion or landslide hazard area. (Ord. 09-19 § 9 (Exh. D); Ord. 06-17 § 4 (Exh. B))