Chapter 15.620


15.620.010    Identification and rating of wetlands.

15.620.020    Critical area report – Additional requirements for wetlands.

15.620.030    Performance standards – General requirements.

15.620.040    Performance standards – Compensatory mitigation requirements.

15.620.010 Identification and rating of wetlands.

A.    Identification and Delineation. Identification of wetlands and delineation of their boundaries pursuant to this chapter shall be done in accordance with the approved federal wetland delineation manual and applicable regional supplements. All areas within the city meeting the wetland designation criteria in that procedure are hereby designated critical areas and are subject to the provisions of this chapter.

B.    Wetland Ratings. Wetlands shall be rated according to the Washington State Department of Ecology wetland rating system found in the Washington State Wetland Rating System for Eastern Washington (Publication No. 14-06-030, Hruby, T., 2014, or as may be subsequently revised by Ecology). These documents contain the definitions and methods for determining if the criteria below are met.

1.    Wetland Rating Categories.

a.    Category I. Category I wetlands are those that represent a unique or rare wetland type, are more sensitive to disturbance than most wetlands, are relatively undisturbed and contain ecological attributes that are impossible or too difficult to replace within a human lifetime, and provide a high level of functions. The following types of wetlands are Category I:

i.    Alkali wetlands;

ii.    Wetlands of high conservation value that are identified by scientist of the Washington Natural Heritage program/DNR;

iii.    Bogs and calcareous fens;

iv.    Mature and old growth forested wetlands over a quarter of an acre with slow growing trees;

v.    Forested wetlands with stands of aspen;

vi.    Wetlands scoring between 22 and 27 points in the Eastern Washington Wetland Rating System.

b.    Category II. Category II wetlands are difficult, though not impossible, to replace, and provide high levels of some functions. These wetlands occur more commonly than Category I wetlands, but still need a relatively high level of protection. Category II wetlands include:

i.    Forested wetlands in the floodplains of rivers;

ii.    Mature and old growth forested wetlands over a quarter of an acre with native fast growing trees;

iii.    Vernal pools; or

iv.    Wetlands scoring between 19 and 21 points in the Eastern Washington Wetland Rating System.

c.    Category III. Category III wetlands have a moderate level of functions (scores between 16 and 18 points). These wetlands can often adequately be replaced with a well-planned mitigation project. Wetlands scoring between 16 to 18 points generally have been disturbed in some way, and are often less diverse and more isolated from other natural resources in the landscape than Category II wetlands.

d.    Category IV. Category IV wetlands have the lowest levels of functions, scoring less than 16 points in the Eastern Washington Rating System, and are often heavily disturbed. These are wetlands that should be able to be replaced and in some cases improved. These wetlands may provide some important functions, and also need to be protected.

2.    Date of Wetland Rating. Wetland rating categories shall be applied as the wetland exists on the date of adoption of the rating system by the local government, as the wetland naturally changes thereafter, or as the wetland changes in accordance with permitted activities. Wetland rating categories shall not change due to illegal modifications.

C.    Mapping. The National Wetland Inventory provides the approximate location and extent of potential wetlands as shown in the city’s geographic system data. Other maps may also be used as they are developed and subsequently adopted by the city. Soil maps produced by U.S. Department of Agriculture National Resources Conservation Service may be useful in helping to identify potential wetland areas. These maps are to be used as a guide for the city, project applicants, and/or property owners, and may be continuously updated as new critical areas are identified. They are a reference and do not provide a final critical area designation.

The exact location of a wetland shall be determined through site visits and identified wetlands shall have their boundaries delineated for regulation consistent with the requirements of this section. [Ord. 4803 § 6, 2018; Ord. 4656 § 1 (Exh. O2), 2013.]

15.620.020 Critical area report – Additional requirements for wetlands.

A.    All critical areas located within 300 feet of the project area that have been designated by the city and are shown on city, state, or federal government agency maps and/or reports shall be addressed in a critical area report for wetlands.

B.    Wetland Analysis. A written assessment of the wetland, the appropriate wetland type, and required buffer under the provisions of this chapter.

C.    As provided for under ECC 15.610.100, the director may require additional information to be included in the critical area report when determined to be necessary for the review of the proposed activity. Additional information for wetlands that may be required includes, but is not limited to, the following:

1.    Vegetative, faunal, and hydrologic characteristics;

2.    Soil and substrate characteristics;

3.    Topographic elevations;

4.    A discussion of water sources supplying the wetland and documentation of the hydrologic regime. Such discussion shall include an analysis of existing and future hydrologic regimes and proposed hydrologic regime for enhanced, created, or restored mitigation areas, if provided for in the project. [Ord. 4803 § 6, 2018; Ord. 4656 § 1 (Exh. O2), 2013.]

15.620.030 Performance standards – General requirements.

A.    Activities may only be permitted in a wetland or wetland buffer if the applicant can show that the proposed activity will not degrade the functions and functional performance of the wetland and other critical areas.

B.    Activities and uses shall be prohibited in wetlands and wetland buffers, except as provided for in this chapter.

C.    Category I Wetlands. Activities and uses shall be prohibited from Category I, except as provided for in the public agency and utility exception, reasonable use exception, and variance sections of this chapter.

D.    Category II, III, and IV Wetlands. Activities and uses that result in unavoidable and necessary impacts may be permitted in Category II, III, and IV wetlands and associated buffers in accordance with an approved critical area report and mitigation plan, but only if the proposed activity is the only reasonable alternative that will accomplish the applicant’s objectives. Full compensation for the acreage and loss functions will be provided under the terms established under ECC 15.620.040(F) and (G).

E.    Wetland Buffers. The following buffer widths have been established in accordance with the best available science. They are based on the category of wetland and habitat score as determined by a qualified wetland professional using the Washington State Wetland Rating System for Eastern Washington: 2014 Update (Ecology Publication No. 14-06-030, Hruby, T., or as may subsequently be revised by Ecology). The adjacent land use intensity is assumed to be high or moderate, see Table 15.620.030(E)(4).

1.    If an applicant chooses not to apply the mitigation measures in Table 15.620.030(E)(2), or is unable to provide a protected corridor where available, then Table 15.620.030(E)(3) must be used.

2.    The buffer widths in Tables 15.620.030(E)(1) and (E)(3) 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.

3.    For low intensity land uses, see Table 15.620.030(E)(4), the buffer may qualify for a buffer reduction by the no less than 75 percent of the otherwise required buffer, as determined by the director.

4.    Measurement of Wetland Buffers. All buffers shall be measured from the wetland boundary as surveyed in the field. The width of the wetland buffer shall be determined according to the wetland category. The buffer for a wetland created, restored, or enhanced as compensation for approved wetland alterations shall be the same as the buffer required for the category of the created, restored, or enhanced wetland. Only fully vegetated buffers will be considered. Lawns, walkways, driveways, and other mowed or paved areas will not be considered buffers.

5.    Increased Wetland Buffer Widths. In those situations in which a SEPA checklist discloses that the above buffer widths may not be sufficient to mitigate the significant adverse environmental impacts of the proposal on the wetland, the director may invoke the procedures in Chapter 15.270 ECC (SEPA) and WAC 197-11-158. The director may require increased buffer widths in accordance with the recommendations of the experienced, qualified professional wetland scientist who produced the required critical areas report and best available science on a case-by-case basis when a larger buffer is necessary to protect wetland functions and values based on site-specific characteristics. The increased buffer width shall not exceed a maximum of 100 percent increase over the buffer width that would otherwise be required by this subsection. This determination shall be based on one or more of the following criteria:

a.    A larger buffer is needed to protect other critical areas;

b.    The buffer or adjacent uplands have a slope greater than 15 percent or is susceptible to erosion and standard erosion-control measures will not prevent adverse impacts to the wetland;

c.    The buffer area has minimal vegetative cover. In lieu of increasing the buffer width where existing buffer vegetation is inadequate to protect the wetland functions and values, implementation of a buffer planting plan may substitute. Where a buffer planting plan is proposed, it shall include densities that are not less than three feet on center for shrubs and eight feet on center for trees and require monitoring and maintenance to ensure success. Existing buffer vegetation is considered inadequate and will need to be enhanced through additional native plantings and (if appropriate) removal of nonnative plants when:

i.    Nonnative or invasive plant species provide the dominant cover,

ii.    Vegetation is lacking due to disturbance and wetland resources could be adversely affected, or

iii.    Enhancement plantings in the buffer could significantly improve buffer functions;

d.    The standard buffer is less than that which is necessary to protect documented endangered, threatened, or sensitive wildlife species which have a primary association with the wetland;

e.    The wetland contains plants listed as sensitive, threatened, or endangered;

f.    The proposed development density is greater than two or more residential units per acre and abuts a Category I or II wetland with high habitat value of 19 to 27 points obtained in the wetland critical areas report; or

g.    The wetland is associated with a stream segment on the 303(d) list for pollutants, or has a total daily maximum load for sediment or temperature and the proposal includes removal of trees and shrubs or untreated stormwater runoff.

6.    Wetland Buffer Width Averaging. The director may allow modification of the standard wetland buffer width in accordance with an approved critical area report and the best available science on a case-by-case basis by averaging buffer widths. Averaging of buffer widths may only be allowed where a qualified professional wetland scientist demonstrates that:

a.    It will not reduce wetland functions or functional performance;

b.    The wetland contains variations in sensitivity due to existing physical characteristics or the character of the buffer varies in slope, soils, or vegetation, and the wetland would benefit from a wider buffer in places and would not be adversely impacted by a narrower buffer in other places;

c.    The total area contained in the buffer area after averaging is no less than that which would be contained within the standard buffer; and

d.    The buffer width is not reduced to less than 75 percent of the standard width or 35 feet.

7.    Interrupted Buffer.

a.    Where a legally established, preexisting use of the buffer exists, those proposed activities that are within the wetland or stream buffer, but are separated from the critical area by an existing permanent substantial improvement, which serves to eliminate or greatly reduce the impact of the proposed activity upon the critical area, are exempt; provided, that the detrimental impact to the critical area does not increase. However, if the impacts do increase, the city shall determine if additional buffer may be required along the impact area of the interruption. Substantial improvements may include developed public infrastructure such as roads and railroads. Substantial improvements may not include paved trails, sidewalks, or parking areas. An allowance for activity in an interrupted buffer may require a critical areas report for the type of critical areas buffer that is affected. In determining whether a critical areas report is necessary, the city shall consider the hydrologic, geologic and/or biological habitat connection potential and the extent and permanence of the interruption.

b.    Where a legally established, preexisting structure or use is located within a regulated wetland or stream buffer and where the regulated buffer is fully paved and does not conform to the interrupted buffer provision above, the buffer will end at the edge of the pavement, adjacent to the wetland or stream.

8.    Buffer Consistency. All mitigation sites shall have buffers consistent with the buffer requirements of this chapter.

9.    Buffer Maintenance. Except as otherwise specified or allowed in accordance with this chapter, wetland buffers and buffers of mitigation sites shall be retained in an undisturbed condition, or shall be maintained as enhanced pursuant to any required permit or approval. Removal of invasive nonnative weeds is required for the duration of the mitigation bond.

10.    Buffer Uses. The following uses may be permitted within a wetland buffer in accordance with the review procedures of this chapter, provided they are not prohibited by any other applicable law and they are conducted in a manner so as to minimize impacts to the buffer and adjacent wetland:

a.    Conservation and Restoration Activities. Conservation or restoration activities aimed at protecting the soil, water, vegetation, or wildlife.

b.    Passive Recreation. Passive recreation facilities designed in accordance with an approved critical area report, including:

i.    Walkways and trails; provided, that those pathways which are generally parallel to the perimeter of the wetland shall be located in the outer 25 percent of the buffer area, and constructed with a surface that does not interfere with the permeability. Raised boardwalks utilizing nontreated pilings area may be acceptable;

ii.    Wildlife viewing structures; and

iii.    Fishing access areas down to the water’s edge that shall be no larger than six feet.

c.    Stormwater Management Facilities. Stormwater management facilities, limited to stormwater dispersion outfalls and bioswales, may be allowed within the outer 25 percent of the buffer of Category III or IV wetlands only; provided, that:

i.    No other location is feasible; and

ii.    The location of such facilities will not degrade the functions or values of the wetland. Stormwater management facilities are not allowed in buffers of Category I or II wetlands.

Table 15.620.030(E)(1) Wetland Buffer Requirements If Table 15.620.030(E)(2) Is Implemented

Wetland Category

Buffer Width Based on Habitat Score (Feet)

3 – 4 Habitat Points

5 Habitat Points

6 – 7 Habitat Points

8 – 9 Habitat Points

Category I: Based on total score





Category I: Forested





Category I: Bogs and wetlands of high conservation value


Category I: Alkali


Category II: Based on total score





Category II: Vernal pool


Category II: Forested





Category III (all)





Category IV (all)


Table 15.620.030(E)(2) Required Measures to Minimize Impacts to Wetlands

(Measures are required, where applicable to a specific proposal)


Required measures to minimize impacts


Direct lights away from wetland


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 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

Change in water regime

Infiltrate or treat, drain, and disperse into buffers 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


Use best management practices to control dust

Table 15.620.030(E)(3) Wetland Buffer Requirements If Table 15.620.030(E)(2) Is Not Implemented

Wetland category

Buffer width (feet) based on habitat score

3 – 4 habitat points

5 habitat points

6 – 7 habitat points

8 – 9 habitat points

Category I: Based on total score





Category I: Forested





Category I: Bogs and wetlands of high conservation value


Category I: Alkali


Category II: Based on total score





Category II: Vernal pool


Category II: Forested





Category III (all)





Category IV (all)


Table 15.620.030(E)(4) Types of Proposed Land Use That Can Result in High, Moderate, and Low Levels of Impacts to Adjacent Wetlands

Level of Impact from Proposed Land Use

Types of Land Use






Retail sales

Residential (more than 1 unit/acre)

High intensity recreation (golf courses, ball fields, etc.)


Residential (1 unit/acre or less)

Moderate intensity open space (parks with biking, jogging, etc.)

Paved trails

Utility corridor right-of-way shared by several utilities and including access/maintenance road


Low intensity open space (hiking, bird-watching, preservation of natural resources, etc.)

Unpaved trails

Utility corridor without a maintenance road or little or no vegetation management

F.    Signs and Fencing of Wetlands.

1.    Temporary Markers. The outer perimeter of the wetland and buffer and the limits of those areas to be disturbed pursuant to an approved permit or authorization shall be marked in the field in such a way as to ensure that no unauthorized intrusion will occur and is subject to inspection by the director prior to the commencement of permitted activities. The director shall have the authority to require that temporary fencing be placed on-site to mark the outer perimeter of the wetland and its associated buffer area. This temporary marking, and any required temporary fencing, shall be maintained throughout construction and shall not be removed until permanent signs, if required, are in place.

2.    Permanent Signs. As a condition of any permit or authorization issued pursuant to this chapter, the director may require the applicant to install permanent signs along the boundary of a wetland or buffer.

a.    Permanent signs shall be made of a metal face with a green color background and white letters; attached to a metal post, or another nontreated material of equal durability; made with a sign face no smaller than one foot by one foot square and no larger than two feet by two feet square; and mounted with the bottom of the sign face no less than three feet above and no more than five feet above adjacent grade. Signs must be posted at a minimum of one per lot of record, or on large parcels every 300 feet, or additional signs as required by the director and must remain unobstructed and be maintained by the property owner in perpetuity. The sign(s) shall be worded as follows or with alternative language approved by the director:

Protected Critical Area

Do Not Disturb

Contact the city of Ellensburg

Regarding Uses and Restriction

b.    The provisions of subsection (F)(2)(a) of this section may be modified by the director as necessary to assure protection of sensitive features or wildlife. [Ord. 4803 § 6, 2018; Ord. 4656 § 1 (Exh. O2), 2013.]

15.620.040 Performance standards – Compensatory mitigation requirements.

Compensatory mitigation for alterations to wetlands shall achieve equivalent or greater biologic functions. Compensatory mitigation plans shall be consistent with the State Department of Ecology Wetland Mitigation in Washington State – Part 2: Developing Mitigation Plans, 2006, or as may be subsequently revised.

A.    Mitigation shall be required in the following order of preference:

1.    Avoiding the impact altogether by not taking a certain action or parts of an action.

2.    Minimizing impacts by limiting the degree or magnitude of the action and its implementation, by using appropriate technology, or by taking affirmative steps to avoid or reduce impacts.

3.    Rectifying the impact by repairing, rehabilitating, or restoring the affected environment.

4.    Reducing or eliminating the impact over time by preservation and maintenance operations.

5.    Compensating for the impact by replacing, enhancing, or providing substitute resources or environments.

B.    Mitigation for Affected Functions or Functions Lost as a Result of the Proposed Activity. Compensatory mitigation actions shall address functions affected by the alteration to achieve functional equivalency or improvement and shall provide similar wetland functions as those lost by the proposed activity, except when:

1.    The lost wetland provides minimal functions as determined by a site-specific function assessment, and the proposed compensatory mitigation action(s) will provide equal or greater functions or will provide functions shown to be limiting within a watershed through a formal Washington State watershed assessment plan or protocol; or

2.    Out-of-kind replacement will best meet formally identified watershed goals, such as replacement of historically diminished wetland types.

C.    Preference of Mitigation Actions. Mitigation actions that require compensation by replacing, enhancing, or substitution shall occur in the following order of preference:

1.    Restoring wetlands on upland sites that were formerly wetlands.

2.    Creating wetlands on disturbed upland sites such as those with vegetative cover consisting primarily of nonnative introduced species. This should only be attempted when there is a consistent source of hydrology and it can be shown that the surface and subsurface hydrologic regime is conducive for the wetland community that is being designed.

3.    Enhancing or rehabilitating significantly degraded wetlands. Such enhancement or rehabilitation should be part of a mitigation package that includes replacing the impacted area meeting appropriate ratio requirements.

D.    Type and Location of Mitigation. Unless it is demonstrated that a higher level of ecological functioning would result from an alternate approach, compensatory mitigation for ecological functions shall be either in-kind and on-site, or in-kind and within the same stream reach, subbasin, or drift cell. Mitigation actions shall be conducted within the same subdrainage basin and on the site as the alteration except when all of the following apply:

1.    There are no reasonable on-site or in-subdrainage basin opportunities or on-site and in-subdrainage basin opportunities do not have a high likelihood of success, after a determination of the natural capacity of the site to mitigate for the impacts. Consideration should include: anticipated wetland mitigation replacement ratios, buffer conditions and proposed widths, hydrogeomorphic classes of on-site wetlands when restored, proposed flood storage capacity, potential to mitigate riparian fish and wildlife impacts (such as connectivity);

2.    Off-site mitigation has a greater likelihood of providing equal or improved wetland functions than the impacted wetland; and

3.    Off-site locations shall be in the same subdrainage basin unless:

a.    Established watershed goals for water quality, flood or conveyance, habitat, or other wetland functions have been established and strongly justify location of mitigation at another site; or

b.    Credits from a state certified wetland mitigation bank are used as mitigation and the use of credits is consistent with the terms of the bank’s certification.

E.    Mitigation Timing. Mitigation projects shall be completed with an approved monitoring plan prior to activities that will disturb wetlands. In all other cases, mitigation shall be completed immediately following disturbance and prior to use or occupancy of the activity or development. Construction of mitigation projects shall be timed to reduce impacts to existing fisheries, wildlife, and flora.

The director may authorize a one-time temporary delay, up to 120 days, in completing minor construction and landscaping when environmental conditions could produce a high probability of failure or significant construction difficulties. The delay shall not create or perpetuate hazardous conditions or environmental damage or degradation, and the delay shall not be injurious to the health, safety, and general welfare of the public. The request for the temporary delay must include a written justification that documents the environmental constraints which preclude implementation of the mitigation plan. The justification must be verified and approved by the city and include a financial guarantee.

F.    Mitigation Ratios.

1.    Acreage Replacement Ratios. The following ratios shall apply to creation or re-establishment, rehabilitation, or enhancement that is in-kind, is on-site, is the same category, is timed prior to or concurrent with alteration, and has a high probability of success. These ratios do not apply to remedial actions resulting from unauthorized alterations; greater ratios shall apply in those cases. These ratios do not apply to the use of credits from a state certified wetland mitigation bank. When credits from a certified bank are used, replacement ratios should be consistent with the requirements of the bank’s certification.

Table 15.620.040(F) Wetland Mitigation Ratios

Category and Type of Wetland

Creation or Re-establishment



Category I: Bog, natural heritage site

Not considered possible

Case by case

Case by case

Category I: Mature forested




Category I: Based on functions




Category II




Category III




Category IV




2.    Increased Replacement Ratio. The director may increase the ratios under the following circumstances:

a.    Uncertainty exists as to the probable success of the proposed restoration or creation;

b.    A significant period of time will elapse between impact and replication of wetland functions;

c.    Proposed mitigation will result in a lower category wetland or reduced functions relative to the wetland being impacted; or

d.    The impact was an unauthorized impact.

G.    Wetland Mitigation Banks.

1.    Credits from a wetland mitigation bank may be approved for use as compensation for unavoidable impacts to wetlands when:

a.    The bank is certified under Chapter 173-700 WAC;

b.    The director determines that the wetland mitigation bank provides appropriate compensation for the authorized impacts; and

c.    The proposed use of credits is consistent with the terms and conditions of the bank’s certification.

2.    Replacement ratios for projects using bank credits shall be consistent with replacement ratios specified in the bank’s certification.

3.    Credits from a certified wetland mitigation bank may be used to compensate for impacts located within the service area specified in the bank’s certification. In some cases, bank service areas may include portions of more than one adjacent drainage basin for specific wetland functions. [Ord. 4803 § 6, 2018; Ord. 4656 § 1 (Exh. O2), 2013.]