28.16.080 Required buffers.
(1) Buffer Requirements. The following buffers shall be required for wetlands based on the rating of the wetland as outlined in PMC 28.16.030, and land use intensity described in Table 28.16.080(2).
Any wetland created, restored, or enhanced as compensation for approved wetland alterations shall also include the standard buffer required for the category of the created, restored, or enhanced wetland.
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Wetland Characteristics |
Buffer Width by Impact of Proposed Land Use |
Other Measures Recommended for Protection |
|---|---|---|
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Category IV Wetlands (For wetlands scoring less than 16 points for all functions) |
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Score for all three basic functions is less than 16 points |
Low – 25 feet Moderate – 40 feet High – 50 feet |
No recommendations at this time |
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Category III Wetlands (For wetlands scoring 16 to 18 points or more for all functions) |
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Moderate level of function for habitat (score for habitat 5 to 7 points) *If wetland scores 8 to 9 habitat points, use Category II buffers |
Low – 75 feet Moderate – 110 feet High – 150 feet |
No recommendations at this time |
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Score for habitat 3 to 5 points |
Low – 40 feet Moderate – 60 feet High – 80 feet |
No recommendations at this time |
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Category II Wetlands (For wetlands scoring 19 to 21 points or more for all functions or having the “Special Characteristics” identified in the rating system) |
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High level of function for habitat (score for habitat 8 to 9 points) |
Low – 100 feet Moderate – 150 feet High – 200 feet |
Maintain connections to other habitat conservation areas |
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Moderate level of function for habitat (score for habitat 5 to 7 points) |
Low – 75 feet Moderate – 110 feet High – 150 feet |
No recommendations at this time |
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High level of function for water quality improvement and low for habitat (score for water quality 8 to 9 points; habitat less than 5 points) |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No additional surface discharges of untreated runoff |
|
Riparian forest |
Buffer width to be based on score for habitat functions or water quality functions |
Riparian forest wetlands need to be protected at a watershed or subbasin scale Other protection based on needs to protect habitat and water quality functions |
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Not meeting above characteristic |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No recommendations at this time |
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Vernal pool |
Low – 100 feet Moderate – 150 feet High – 200 feet Or develop a regional plan to protect the most important vernal pool complexes; buffers of vernal pools outside protection zones can then be reduced to: Low – 40 feet Moderate – 60 feet High – 80 feet |
No intensive grazing or tilling of wetland |
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Category I Wetlands (For wetlands scoring 22 points or more for all functions or having the “Special Characteristics” identified in the rating system) |
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Wetlands of High Conservation Value |
Low – 125 feet Moderate – 190 feet High – 250 feet |
No additional surface discharges to wetland or its tributaries No septic systems within 300 feet of wetland Restore degraded parts of buffer |
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High level of function for habitat (score for habitat 8 to 9 points) |
Low – 100 feet Moderate – 150 feet High – 200 feet |
Restore degraded parts of buffer Maintain connections to other habitat conservation areas |
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Moderate level of function for habitat (score for habitat 5 to 7 points) |
Low – 75 feet Moderate – 110 feet High – 150 feet |
No recommendations at this time |
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High level of function for water quality improvement (8 to 9 points) and low for habitat (less than 5 points) |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No additional surface discharges of untreated runoff |
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Not meeting above characteristics |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No recommendations at this time |
Note:See Table 28.16.080(2) in this section, or as amended by Ecology, for types of land uses that can result in low, moderate, and high impacts to wetlands.
(2) The land use intensity table describes the types of proposed land use that can result in high, moderate, and low levels of impacts to adjacent wetlands.
(3) Measuring Buffer Dimensions. Wetland buffers shall be measured horizontally in a landward direction from the delineated wetland edge.
(4) Wetlands Adjacent to Slopes. Where lands adjacent to a wetland display a continuous slope of 25 percent or greater, the buffer shall include such sloping areas. Where the horizontal distance of the sloping area is greater than the required standard buffer, the buffer shall be extended to a point 25 feet beyond the top of the bank of the sloping area.
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Level of Impact from Proposed Change in Land Use |
Types of Land Use Based on Common Zoning Designations |
|---|---|
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High |
• Commercial • Urban • Industrial • Institutional • Retail sales • Residential (more than one unit/acre) • Conversion to high-intensity agriculture (dairies, nurseries, greenhouses, growing and harvesting crops requiring annual tilling and raising and maintaining animals, etc.) • High-intensity recreation (golf courses, ball fields, etc.) • Small lot agricultural that are not of long-term commercial significance |
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Moderate |
• Residential (one unit/acre or less) • Moderate-intensity open space (e.g., parks with impervious surface for biking, jogging) • Paved driveways and gravel driveways serving three or more residences • Paved trails • Utility corridor or right-of-way shared by several utilities and including access/maintenance road |
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Low |
• Forestry (cutting of trees only) with controlled cutting under appropriate authorization • Low-intensity open space (e.g., hiking, bird-watching, preservation of natural resources) • Unpaved trails • Utility corridor without a maintenance road and little or no vegetation management |
[Ord. 4525 § 1, 2021; Ord. 3911 § 2, 2009; Code 1970 § 28.16.080.]