Environmentally Critical Areas | Environment & Sustainability
the bank if the ordinary high water mark cannot be identified:
i. The minimum buffer required for the stream class involved or a 25-foot buffer beyond the top of the slope, whichever is greater, if the horizontal length of the slope, including small benches and terraces, is within the buffer for that stream class; or ii. A 25-foot buffer beyond the minimum buffer width required for the stream class involved if the horizontal length of the slope, including small benches and terraces, extends beyond the buffer for that stream class. c. Any stream adjoined by a riparian wetland or other contiguous critical area shall have the buffer required for the stream type involved or the buffer that applies to the wetland or other critical area, whichever is greater. d. Buffer Averaging. Buffer width averaging may be allowed by the City if: i. It will provide additional natural resource protection, as long as the total area contained in the buffer on the development proposal site does not decrease (see also SDC 21.06.020F.2.d. for buffer compensation requirements for trails); ii. The stream contains variations in sensitivity due to existing physical characteristics or the character of the buffer varies in slope, soils, or vegetation, and the stream would benefit from a wider buffer in places and would not be adversely impacted by a narrower buffer in other places; iii. The buffer width is not reduced to less than 50 percent of the standard buffer;
STREAM BUFFERS
Stream Type
Standard Buffer (ft)
Type S Type F
150’ 150’
Type Np Type Ns
75’ 50’
i. Where a legally established and constructed street transects a stream buffer, the department may approve a modification of the standard buffer width to the edge of the street if the isolated part of the buffer does not provide additional protection of the stream and provides insignificant biological, geological or hydrological buffer functions relating to the stream. If the resulting buffer distance is less than 50 percent of the standard buffer, no further reduction shall be allowed. ii. Where a buffer has been previously established on a legally created parcel or tract that was legally established according to the regulations in place at the time of establishment, and is permanently recorded on title or placed within a separate tract, the buffer shall remain as previously established, provided it is equal to or greater than 50 percent of the required standard buffer distance for the applicable stream category. b. Any stream with an ordinary high water mark within 25 feet of the toe of a slope 30 percent or steeper, but less than 40 percent, shall have:
Effective | January 1, 2022
Title 21: Sammamish Development Code | 113
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