14.28.280 Wetland buffers--Standard buffer zone widths

14.28.280 Wetland buffers--Standard buffer zone widths.

A. Wetland buffer zones shall be required for all regulated activities adjacent to regulated wetlands. 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. All buffers shall be measured from the wetland boundary as surveyed in the field pursuant to the requirements of LMC 14.28.090.

B. The width of the wetland buffer zone shall be determined according to wetland category, the proposed land use and the wetland’s identified functions and values. This methodology shall be applied except when the community and economic development director, through consultation with the Department of Ecology, determines that another methodology better addresses best available science and/or the specific circumstances of the wetland and wetland protection needs.

C. Where an area of a wetland may be classified under more than one category, the category having the greatest buffer area shall apply. These buffer widths presume that buffer area is comprised of relatively intact native vegetation community adequate to protect the wetland functions at values at the time of the proposed activity. If the vegetation is not adequate, then the buffer width may need to be increased or planted to maintain the standard width. Buffer width required for points identified pursuant to the Department of Ecology wetland rating system. (See Table 14T-19).

1. For wetlands that score six or more points for habitat function, the following conditions must be maintained in order to use the standard buffers, as follows:

a. If an existing, relatively undisturbed vegetated corridor at least one hundred feet wide exists between the on-site wetland and other priority habitats, as defined by the Washington State Department of Fish and Wildlife, and the off-site portion of the corridor is already protected via an existing conservation easement, critical areas regulations, or other legal requirement, the portion of the corridor on-site must also be protected by a similar legal protection. All other applicable criteria found in subsection (C)(2) of this section must also be met. The evaluation of presence or absence of the conditions described above must be completed as part of the critical areas report.

b. If no such corridor is present to protect, the standard buffers alone may be used with the other applicable criteria contained in this section. If an option for protection of a corridor, as defined under subsection (C)(1)(a) of this section, exists on the parcel, but is not provided, standard buffer widths must be increased by thirty-three percent.

2. The buffer widths in Table 14T-19 assume that the buffer is vegetated with a native plant community appropriate for the ecoregion. If the existing buffer is unvegetated, sparsely vegetated, or vegetated with invasive species that do not perform needed functions, the buffer should either be planted to create the appropriate plant community or the buffer should be widened to ensure that adequate functions of the buffer are provided.

a. Table 14T-19. Wetland Buffer Table.

Wetland Category and Type	Buffer Width (in feet) Based on Habitat Score
Wetland Category and Type	3--5 (Low)	6--7 (Medium)	8--9 (High)
I: Estuarine and Coastal Lagoons	150 (buffer width not based on habitat scores)
I: Bogs and Wetlands of High Conservation Value	190		225
I: All Others	75	110	225
II: Estuarine and Coastal Lagoons	110 (buffer width not based on habitat scores)
II: All	75	110	225
III: All	60	110	225
IV: All	40

b. Table 14T-68. Required measures to minimize impacts to wetlands. Measures are required, where applicable to a specific proposal. If not implemented, wetland buffers as indicated in Table 14T-69 will be used.

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’ 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 ft 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 (per PSAT publication on LID techniques)
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

c. Table 14T-69. The following wetland buffer requirements if habitat corridor is not provided per subsection (C)(1) of this section or minimization measures per subsection (C)(2)(b) of this section are not implemented:

Wetland Category and Type	Buffer Width (in feet) Based on Habitat Score (if minimization measures are not met)
Wetland Category and Type	3--5 (Low)	6--7 (Medium)	8--9 (High)
I: Estuarine and Coastal Lagoons	200 (buffer width not based on habitat scores)
I: Bogs and Wetlands of High Conservation Value	250		300
I: All Others	100	150	300
II: Estuarine and Coastal Lagoons	150 (buffer width not based on habitat scores)
II: All	100	150	300
III: All	80	150	300
IV: All	50

(Ord. 1585 §3, 2021; Ord. 1505 §10, 2017; Ord. 1449 §7, 2014; Ord. 1295 §1, 2007; Ord. 1215 §8, 2003; Ord. 912 §1 Sec. 7.1(a), 1991).