18.65.320 Wetlands – Buffers | Covington Municipal Code

18.65.320 Wetlands – Buffers.

(1) Wetland – Buffers. Except as otherwise provided in this section, buffers shall be provided from the wetland edge in accordance with the following standards:

(a) The standard buffer widths of the following table shall apply if impact minimization measures are included in accordance with subsection (2), (3), or (4) of this section:

WETLAND CATEGORY AND CHARACTERISTICS	BUFFER
Category I
Bog	225 feet
Habitat score from 8 to 9 points	225 feet
Habitat score from 6 to 7 points	110 feet
Category I wetlands not meeting any of the criteria above	75 feet
Category II
Habitat score from 8 to 9 points	225 feet
Habitat score from 6 to 7 points	110 feet
Category II wetlands not meeting any of the criteria above	75 feet
Category III
Habitat score from 8 to 9 points	225 feet
Habitat score from 6 to 7 points	110 feet
Category III wetlands not meeting any of the criteria above	60 feet
Category IV	40 feet

(2) Buffer Impact Minimization Measures. The following measures shall be implemented in order to utilize the standard buffer widths as noted in subsection (1) of this section.

(a) The following measures shall be used by an applicant to obtain a standard buffer width under subsection (1) of this section:

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 heavy industry, 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 within 150 feet of wetland
	•	Apply integrated pest management
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 of wildlife by humans and pets using vegetation appropriate for the ecoregion
Pets and human disturbance	•	Place wetland and its buffer in a separate tract or protect with a conservation easement
Dust	•	Use best management practices to control dust
Degraded buffer condition	•	Nonnative plants to be removed and replaced with native vegetation per an approved landscaping plan to be bonded and monitored for not less than a five-year period after completion to assure at least 80% survival of plantings
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
Disruption of corridors or potential or existing wildlife habitat connections	•	Maintain connections to off-site areas that are undisturbed
	•	Restore corridors or connections to off-site habitats by replanting

(3) If a Category I or II wetland with habitat score seven points or greater is located within 300 feet of a priority habitat area as defined by the Washington State Department of Fish and Wildlife, the buffer established by subsection (1) of this section shall be increased by 50 feet unless:

(a) The applicant provides a relatively undisturbed vegetated corridor at least 100 feet wide between the wetland and all priority habitat areas located within 300 feet of the wetland. The corridor shall be protected for the entire distance between the wetland and the priority habitat through dedication to the City of a conservation easement, native or the equivalent; and

(b) The applicable mitigation measures in subsection (2)(a) of this section shall be applied.

(4) Buffer Averaging. The Director may approve a modification of the standard buffer widths required on a case-by-case basis by averaging buffer widths, based on review of a critical area report prepared by a qualified professional describing the current functions of the wetland and its buffer and the measures that will be taken to ensure that there is no loss of wetland function due to buffer averaging, if:

(a) The Director determines that the ecological structure and function of the buffer after averaging are equivalent to or greater than the structure and function before averaging;

(b) The resulting buffer meets the following standards:

(i) The total area of the buffer after averaging is equivalent to or greater than the area of the buffer before averaging;

(ii) The additional buffer is contiguous with the standard buffer; and

(iii) Averaging does not occur into the buffer of another wetland or stream except as otherwise allowed.

(c) In no case shall a standard averaged buffer width be reduced to less than 75 percent of the standard buffer at any location;

(d) Averaging does not result in any impact to other critical areas; and

(e) Averaging does not result in a significant adverse impact to habitat associated with species of local importance.

(5) Where a legally established street transects a wetland buffer, the Director may approve a modification of the minimum required buffer width to the edge of the roadway if part of the buffer is on the other side of the roadway:

(a) Does not provide additional protection of the proposed development or the wetland;

(b) Does not perform any biological, geological or hydrological buffer functions relating to the undisturbed portions of the wetland buffer;

(c) The alterations allowed in CMC 18.65.050 are not allowed in buffers established in accordance with this subsection; and

(d) The buffer widths established in accordance with this subsection are not further modified as provided for in subsections (3) and (4) of this section.

(6) The City may establish minimum buffer widths for wetlands that are created as a result of enhancement or restoration projects that are not mitigation for a development proposal or alteration. (Ord. 09-19 § 9 (Exh. D); Ord. 06-17 § 4 (Exh. B))