14.100.550 Fish and Wildlife Habitat Conservation Areas—Water Bodies—Buffers.
The shoreline administrator shall have the authority to require buffers from the edges of all streams in accordance with the following:
A. Buffers shall be established for activities as necessary to protect the integrity, functions and values of the resource. Buffer widths shall reflect the sensitivity of the species or habitat and the type and intensity of the adjacent human use or activity.
B. The buffer widths required by this section are based on scientific studies of the conditions necessary to sustain ecological functions and values to support anadromous and resident fish and presume the existence of a dense native vegetation community in the buffer zone adequate to protect the stream functions and values at the time of the proposed activity. Buffers shall be measured as follows:
1. Type S Water. Buffers for all waters, as inventoried as “shorelines of the state” under the jurisdiction of the SMA, except associated wetlands, shall be regulated in accordance with Section 14.50.430.02.
2. Type F-A Water. Segments of natural waters other than Type S waters, which are greater than ten (10) feet in width: buffer width of one hundred fifty (150) feet.
3. Type F-B Water. Segments of natural waters other than Type S waters, which are less than ten (10) feet in width: buffer width of one hundred (100) feet.
4. Type Np Water. Segments of natural waters that are perennial nonfish habitat streams: buffer width of seventy-five (75) feet.
5. Type Ns Water. Segments of natural waters within defined channels that are seasonal, nonfish habitat streams: buffer width of fifty (50) feet.
6. Nonfish-bearing streams in existing subdivisions:
a. Where streams have been placed in separate tracts, buffers will be provided by the tract, provided a minimum dimension of twenty-five (25) feet from the edge of the stream is provided;
b. Where streams have not been placed in separate tracts, or if a minimum dimension of twenty-five (25) feet from the edge of the stream is not provided, buffers will meet the dimensional requirements in subsection (B)(4) of this section, unless existing structures are located within the buffer. In that case, the following provisions shall apply:
(1) An inner riparian buffer shall be provided with a dense community of native trees, shrubs and groundcover. The dimension of this buffer shall be a minimum of fifteen (15) feet, and may be expanded if sufficient clearance is available between the stream and existing primary structures;
(2) An outer riparian buffer may be provided to extend within ten (10) feet of an existing primary structure. Within the outer buffer, a maximum of twenty-five (25) percent of the zone may be used as grass turf, with the balance a dense community of native trees, shrubs and groundcover.
C. Buffer Measurement.
1. The buffer shall be measured landward horizontally on both sides of the water body from the OHWM as identified in the field perpendicular to the alignment of the stream or lake/pond bank.
2. The required buffer shall be extended to include any adjacent regulated wetland(s), landslide hazard areas, and/or erosion hazard areas and required buffers, but shall not be extended across roads or other lawfully established structures or hardened surfaces that are disconnected functionally and effectively from the stream.
3. Where lands adjacent to a stream display an average continuous slope of twenty (20) percent to thirty-five (35) percent and the required buffer is less than one hundred (100) feet, the buffer shall extend to a thirty (30) percent greater dimension.
4. In all cases, where slopes within the required buffer exceed thirty-five (35) percent, the buffer shall extend to a minimum dimension of twenty-five (25) feet from the top of said slopes or if a buffer associated with a geological hazard is present, to whichever extent is greater.
5. Buffers in Conjunction with Other Critical Areas. Where other critical areas defined in this chapter fall within the water body buffer, the buffer area shall be the most expansive of the buffers applicable to any applicable critical area.