18.08.100 Wetlands – Buffer areas.
A. Following the department’s determination of the category for a wetland associated with a proposal, the department shall determine appropriate buffer widths. Wetland buffer zones shall be evaluated for all development proposals and activities adjacent to wetlands to determine their need to protect the integrity, functions and values of the wetland. Wetland buffer widths are determined by the category of wetland, the intensity of impacts of a land use and the functions or special characteristics of the wetland that need to be protected as determined by the rating system. All wetland buffer zones are measured perpendicular from the wetland boundary as surveyed in the field. Except as otherwise permitted by this chapter, wetland buffers shall consist of a relatively intact native vegetation community adequate to protect the wetland functions and values at the time of proposed activity. If the vegetation is inadequate then the buffer width shall be planted to maintain the buffer width.
B. Impact of Land Use. Different uses of land can result in a high, moderate or low level of impact to adjacent wetlands. Types of land use are categorized into impact levels as shown on the following table:
|
Level of Impact from Land Use |
Types of Land Uses Based on Common Use Categories |
|---|---|
|
High |
Residential uses (greater than one unit per acre); schools; churches; public facilities, public/private services and government administrative uses (excluding parks, rights-of-way and utilities); lodging uses; personal, professional, product and automotive services; health care services; commercial and sales uses; animal clinics and kennels; marine-related uses; industrial uses; restaurant uses; museum, club and recreation hall uses; high-intensity parks, outdoor and indoor recreation (golf courses, ballfields, tennis clubs, swimming pools, etc.); conversion to high-intensity agriculture (dairies, nurseries, greenhouses, growing and harvesting crops requiring annual tilling and raising and maintaining animals, etc.); hobby farms. |
|
Moderate |
Residential uses (less than one unit per acre); moderate-intensity parks and outdoor recreation (parks with biking, jogging, etc.); conversion to moderate-intensity agriculture (orchards, hay fields, etc.) and paved trails; building of logging roads; utility corridor or right-of-way shared by several utilities and including access/maintenance road. |
|
Low |
Forestry (cutting of trees only); low-intensity parks and open space (hiking, bird-watching, preservation of natural resources, etc.) and unpaved trails; utility corridor without a maintenance road and little or no vegetation management. |
C. If a wetland meets more than one of the wetland characteristics listed in the tables in subsection D, E, F or G of this section, the buffer width required to protect the wetland is the widest buffer width.
D. Category I Wetlands. The following buffer widths for Category I wetlands are required:
|
Wetland Characteristics |
Buffer Widths by Impact of Land Use |
Other Protection Measures Required |
|---|---|---|
|
Natural Heritage Wetlands |
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 |
|
Bogs |
Low – 125 feet Moderate – 190 feet High – 250 feet |
No additional surface discharges to wetland or its tributaries Restore degraded parts of buffer |
|
Forested |
Buffer width to be based on score for habitat functions or water quality functions |
If forested wetland scores high for habitat, need to maintain connections to other habitat areas Restore degraded parts of buffer |
|
Estuarine |
Low – 100 feet Moderate – 150 feet High – 200 feet |
None required |
|
Wetlands in coastal lagoons |
Low – 100 feet Moderate – 150 feet High – 200 feet |
None required |
|
High level of function for habitat (score for habitat 8 – 9 points) |
Low – 150 feet Moderate – 225 feet High – 300 feet |
Maintain connections to other habitat areas Restore degraded parts of buffer |
|
Moderate level of function for habitat (score for habitat 5 – 7 points) |
Low – 75 feet Moderate – 110 feet High – 150 feet |
None required |
|
High level of function for water quality improvement (8 – 9 points) and low for habitat (3 – 4 points) |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No additional surface discharges of untreated runoff |
|
Not meeting any of the above characteristics |
Low – 50 feet Moderate – 75 feet High – 100 feet |
N/A |
E. Category II Wetlands. The following buffer widths for Category II wetlands are required:
|
Wetland Characteristics |
Buffer Widths by Impact of Land Use |
Other Protection Measures Required |
|---|---|---|
|
High level of function for habitat (score for habitat 8 – 9 points) |
Low – 150 feet Moderate – 225 feet High – 300 feet |
Maintain connections to other habitat areas |
|
Moderate level of function for habitat (score for habitat 5 – 7 points) |
Low – 75 feet Moderate – 110 feet High – 150 feet |
None required |
|
High level of function for water quality improvement and low for habitat (score for water quality 8 – 9 points; habitat 3 – 4 points) |
Low – 50 feet Moderate – 75 feet High – 100 feet |
No additional surface discharges of untreated runoff |
|
Estuarine |
Low – 75 feet Moderate – 110 feet High – 150 feet |
None required |
|
Interdunal |
Low – 75 feet Moderate – 110 feet High – 150 feet |
None required |
|
Not meeting above characteristics |
Low – 50 feet Moderate – 75 feet High – 100 feet |
None required |
F. Category III Wetlands. The following buffer widths for Category III wetlands are required:
|
Wetland Characteristics |
Buffer Widths by Impact of Land Use |
Other Protection Measures Required |
|---|---|---|
|
Moderate to high level of function for habitat (score for habitat 5 – 9 points) |
Low – 75 feet Moderate – 110 feet High – 150 feet |
None required |
|
Not meeting above characteristic |
Low – 40 feet Moderate – 60 feet High – 80 feet |
None required |
G. Category IV Wetlands. The following buffer widths for Category IV wetlands are required:
|
Wetland Characteristics |
Buffer Widths by Impact of Land Use |
Other Protection Measures Required |
|---|---|---|
|
Score for all three basic functions is 9 – 15 points |
Low – 25 feet Moderate – 40 feet High – 50 feet |
None required |
H. A 15-foot building setback is required from the edge of a wetland buffer.
I. Where a legally established developed roadway transects a wetland 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 road does not provide any buffer functions to protect the wetland in question.
J. Where a legally established bulkhead transects a wetland buffer, the director may approve a modification of the minimum required buffer width as long as the biologic, hydrologic and water quality functions of the wetland are protected. This modification would be evaluated on a case-by-case basis and rely upon a sensitive areas study provided by a qualified biologist where it can be demonstrated that an equal or greater protection of the wetland would occur. Measures may include bioengineering of shoreline protection, revegetation with native species, or other shoreline or buffer enhancement measures. (Ord. 1322 § 8, 2015; Ord. 1036 § 17, 2006; Ord. 726 § 4, 1996; Ord. 628 § 1, 1992; Ord. 611 § 1, 1991).