35.35.050 Regulations – Wetland buffers.
(1) Buffer Widths. Buffers shall be established and maintained to protect all regulated wetlands. The standard wetland buffer width shall be determined according to the regulated wetland classification and category (CCC 35.35.040), wetland characteristics, and the level of impact (Table 7-1) from proposed change in land use. The resulting buffers are shown in Tables 7-2, 7-3 and 7-4 for low, moderate and high impact land uses, respectively. Buffer widths shall be measured along a horizontal line perpendicular to the delineated regulated wetland edge (CCC 35.35.040) as marked in the field.
(2) Reduction of High Impact Land Use Buffer Widths. Wetland buffer widths for new high impact land uses (Table 7-4) may be reduced to those required for moderate impact land uses (Table 7-3) under the following conditions:
(a) For wetlands that score moderate or high for habitat (five points or more for the habitat functions), the width of buffer can be reduced if both of the following conditions are met:
(i) A vegetated corridor at least 100 feet wide is protected between the wetland and any priority habitats (see definition) identified on maps by the Washington Department of Fish and Wildlife available to the public. The corridor must be protected for the entire distance between the wetland and the priority habitat by some type of legal protection such as a conservation easement.
(ii) The measures in Table 7-5 are implemented, where applicable, to minimize the impacts of adjacent land uses.
(b) For wetlands that score less than five points for habitat, the buffer width can be reduced to that required for moderate impact land uses by implementing the measures in Table 7-5, where applicable, to minimize the impacts of the proposed land uses.
(3) Wetland Buffer Condition. Wetland buffers shall be retained in a natural condition or may be improved to enhance buffer functions and values. Buffers shall be maintained in a predominantly well vegetated and undisturbed condition defined as an average density of at least 150 trees and/or shrubs per acre or 55 percent areal cover of woody vegetation, whichever is greater. The Administrator may allow exceptions when existing buffer vegetation does not meet this tree/shrub requirement for sites that are otherwise predominantly characterized by native vegetation. The vegetated area shall comprise at least 80 percent of the buffer area. Native vegetation is preferred but existing non-native trees and shrubs may be allowed as long as they provide similar habitat functions to native trees and shrubs. Invasive or noxious weed species shall not count toward the density or cover thresholds. Alterations to buffers that are not associated with an allowed use or development shall be prohibited.
(4) Multiple Buffers. In the event that buffers for any shorelines and/or critical areas are contiguous or overlapping, the landward-most edge of all such buffers shall apply.
Level of Impact from Proposed Change in Land Use | Land Use Types |
|---|---|
High | • Commercial, industrial, and institutional uses • Multifamily residential • Residential (more than one unit per acre) • Conversion to high intensity agriculture (e.g., dairies, nurseries, greenhouses, animal and livestock, and growing and harvesting crops requiring annual tilling) • High intensity recreation (golf courses, sport fields, playgrounds, etc.) • Other uses not listed in the moderate or low impact category, or similar expected level of impacts to such uses |
Moderate | • Single-family residential (parcel size one acre or greater) • Moderate intensity recreational open spaces (e.g., parks with biking, jogging, etc.) • Conversion to moderate intensity agriculture (orchards, hay fields, etc.) • Paved trails • Building of logging roads • Utility corridor right-of-way shared by several utilities and including access/maintenance road |
Low | • Forest management • Single-family residential on existing lots of record on parcels five acres (or 1/128 of a standard section) or greater in size meeting the criteria for minor new development in CCC 35.30.030(2) • Low intensity recreational open spaces (e.g., hiking) with no or minimal vegetation clearing and management • Unpaved trails • Utility corridor without a maintenance road and little or no vegetation management |
Wetland Category | Wetland Characteristics • Habitat (H) | Standard Buffer Width |
|---|---|---|
Category I (Total of scores for all functions is 23 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 150 feet |
Bogs or wetlands of high conservation value | 125 feet | |
Estuarine and coastal lagoons | 100 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 75 feet | |
Not meeting any of above characteristics | 50 feet | |
Category II (Total of scores for all functions is 20 – 22 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 150 feet |
Estuarine | 75 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 75 feet | |
Not meeting any of above characteristics | 50 feet | |
Category III (Total of scores for all functions is 16 – 19 points) | Moderate level of habitat function (H score 5 – 7 points) | 75 feet |
Low habitat function (H score 3 – 4 points) | 40 feet | |
Category IV (Total of scores for all functions is less than 16 points) | Score for all basic functions is less than 16 points | 25 feet |
Wetland Category | Wetland Characteristics • Habitat (H) | Standard Buffer Width |
|---|---|---|
Category I (Total of scores for all functions is 23 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 225 feet |
Bogs or wetlands of high conservation value | 190 feet | |
Estuarine and coastal lagoons | 150 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 110 feet | |
Not meeting any of above characteristics | 75 feet | |
Category II (Total of scores for all functions is 20 – 22 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 225 feet |
Estuarine | 110 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 110 feet | |
Not meeting any of above characteristics | 75 feet | |
Category III (Total of scores for all functions is 16 – 19 points) | Moderate level of habitat function (H score 5 – 7 points) | 110 feet |
Low habitat function (H score 3 – 4 points) | 60 feet | |
Category IV (Total of scores for all functions is less than 16 points) | Score for all basic functions is less than 16 points | 40 feet |
Wetland Category | Wetland Characteristics • Habitat (H) | Standard Buffer Width |
|---|---|---|
Category I (Total of scores for all functions is 23 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 300 feet |
Bogs or wetlands of high conservation value | 250 feet | |
Estuarine and coastal lagoons | 200 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 150 feet | |
Not meeting any of above characteristics | 100 feet | |
Category II (Total of scores for all functions is 20 – 22 points or having “special characteristics” identified in the rating form) | High level of habitat function (H score 8 – 9 points) | 300 feet |
Estuarine | 150 feet | |
Moderate level of habitat function (H score 5 – 7 points) | 150 feet | |
Not meeting any of above characteristics | 100 feet | |
Category III (Total of scores for all functions is 16 – 19 points) | Moderate level of habitat function (H score 5 – 7 points) | 150 feet |
Low habitat function (H score 3 – 4 points) | 80 feet | |
Category IV (Total of scores for all functions is less than 16 points) | Score for all basic functions is less than 16 points | 50 feet |
Disturbance | Required Measures to Minimize Impacts |
|---|---|
Lights | • Direct lights away from wetland |
Noise | • Locate activity that generates noise away from wetland • If warranted, enhance existing buffer with native vegetation plantings adjacent to noise source • For activities that generate relatively continuous, potentially disruptive noise, such as certain heavy industry or mining, establish an additional 10-foot heavily vegetated buffer strip immediately adjacent to the outer wetland buffer |
Toxic runoff | • Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered • Establish covenants limiting use of pesticides and herbicides within 150 feet of wetland • Apply integrated pest management |
Stormwater runoff | • Retrofit stormwater detention and treatment for roads and existing adjacent development • Prevent channelized flow from lawns that directly enters the buffer • Use low intensity development techniques (for more information refer to the drainage ordinance and manual) |
Change in water regime | • Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces and new lawns |
Pets and human disturbance | • Use privacy fencing OR plant dense vegetation to delineate buffer edge and to discourage disturbance using vegetation appropriate for the ecoregion • Place wetland and its buffer in a separate tract or protect with a conservation easement |
Dust | • Use best management practices to control dust |
(5) Interrupted Buffer. When a wetland buffer contains an existing legally established public or private (does not include driveways) road, the County may allow development on the landward side of the road; provided, that the development will not have an adverse impact to the wetland. Likewise, in an existing subdivision where there is a legally established residence on a developed lot between the wetland and the proposed lot for development, the buffer shall not extend onto the undeveloped lot. The County shall consider the hydrologic, geologic, and/or biological habitat connection potential and the extent and permanence of the buffer interruption.
(6) Buffer Averaging. The Administrator may allow averaging of the standard wetland buffer widths shown in Tables 7-2 through 7-4. The averaging shall only be allowed when necessary to accommodate a single-family residential development or a water-dependent or water-related development in those limited instances when adherence to the standard buffer is infeasible or presents a substantial hardship because of site conditions, lot configuration or other circumstances. To ensure no net loss of buffer area, the buffer width may be reduced in one location and must be increased in another location to maintain the same overall buffer area. Residential subdivisions and non-water-dependent non-water-related developments shall not be eligible for wetland buffer averaging except through a shoreline variance. Proposals for buffer averaging shall not require a shoreline variance or compensatory mitigation if all of the following conditions are met:
(a) The minimum width of the buffer at any given point is at least 75 percent of the standard width per Tables 7-2 through 7-4, or 35 feet, whichever is greater.
(b) The net buffer area (acreage) after averaging is the same as the standard buffer area without averaging.
(c) The reduced portion of the buffer cannot exceed 40 percent of the buffer length. In other words, the buffer width along 60 percent of the buffer length must remain unreduced. For example, in a 100-foot-long segment of wetland buffer, a reduced buffer width may be applied to no more than 40 feet of length.
(d) The area that is added to the buffer to offset the reduction is well vegetated as defined in subsection (3) of this section. The Administrator shall require planting or enhancement of the buffer to meet the stated density and/or cover targets if the existing vegetation conditions of the buffer do not meet the density and/or cover targets.
(7) Mitigation for Buffer Averaging. Prior to approving a request for wetland buffer averaging, the Administrator shall ensure the development and uses adjacent to the reduced buffer are designed to separate and screen the wetland from impacts such as noise, glare, vegetation trampling, etc. The site design shall consider the varying degrees of impacts of different land uses. For example, parking lots, store entrances, and roads generally have higher noise and glare impacts than the rear of the store. Site screening should take advantage of natural topography or existing vegetation, wherever possible. Where natural screening is not available, berms, landscaping, and structural screens should be implemented (e.g., orient buildings to screen parking lots and store entrances from critical areas).
(8) Buffer Reduction. Alterations of the buffer that do not meet the minimum standard buffer requirements or buffer averaging requirements of this section shall require a shoreline variance in accordance with Chapter 35.50 CCC.
(9) Hazard Tree Removal. Removal of a hazard tree may be allowed in the wetland or buffer when trimming is not sufficient to address the hazard. Where the hazard is not immediately apparent to the Administrator, the hazard tree determination shall be made after the Administrator review of a report prepared by a qualified arborist or forester. Any tree removal shall be the minimum necessary to balance protection of the critical area and its buffer with protection of life and property. To mitigate impacts of tree removal, the Administrator shall require planting of tree(s) or other vegetation, and may require leaving hazard trees taken down in buffer areas for habitat and/or woody debris recruitment along riparian corridors.
(10) Increased Wetland Buffers. The Administrator may increase wetland buffer zone widths, not to exceed 300 feet, for a development project on a case-by-case basis when a larger buffer is necessary to protect wetland functions and values. Such determination shall be based on site-specific and project-related conditions which include, but are not limited to:
(a) Wetland sites with known locations of endangered or threatened species for which a habitat management plan indicates a larger buffer is necessary to protect habitat values for such species;
(b) The adjacent land is susceptible to severe erosion, and erosion control best management practices will not effectively prevent adverse wetland impacts; and/or
(c) The buffer condition is significantly degraded (e.g., minimal vegetation, lack of native vegetation).
(11) Buffer for Wetland Mitigation Sites. Any wetland that is created, restored, or enhanced as compensation for an approved wetland alteration shall have the standard buffer required for the category of the created, restored, or enhanced wetland.