Skip to main content
Loading…
This section is included in your selections.

(1) Purpose. The purpose of this section is to promote public health and welfare by instituting local measures to preserve naturally occurring wetlands that exist in the City’s shoreline jurisdiction for their associated value. These areas may serve a variety of vital functions, including, but not limited to, flood storage and conveyance, water quality protection, recharge and discharge areas for groundwater, erosion control, sediment control, fish and wildlife habitat, recreation, education, and scientific research.

(2) Wetland Designation. Under this chapter, wetlands shall be designated in accordance with the definitions, methods, and standards set forth in the approved 1987 USACE Wetlands Delineation Manual, as amended and its applicable regional supplements, as amended (The Arid West Final Regional Supplement was last updated in 2008 at time of SMP adoption). All areas within the City of Pasco meeting the criteria identified in this delineation manual, regardless of whether or not these areas have been formally identified as wetlands, are hereby designated as wetland critical areas and are subject to the provisions of this chapter.

(3) Wetland Rating (Classification).

(a) The wetlands rating system is intended to differentiate between wetlands based on their sensitivity to disturbance, rarity, irreplaceability, and the functions and values they provide. A general description of wetland categories and the rationale for each category is provided in PMC 29.05.070, Definitions (see “Wetland Categories”).

(b) Wetlands shall be rated (classified) as either Category I, Category II, Category III, or Category IV according to the criteria listed in this section. This rating system is based on the Washington Department of Ecology’s Washington State Wetlands Rating System for Eastern Washington-Ecology Publication No. 14-06-030 (October 2014), as amended. The most current edition of this document should be used in classifying wetlands and developing wetland mitigation plans.

(4) Wetland Indicators. The following indicators of wetland presence shall be used by the Shoreline Administrator to determine if a wetland detailed study is needed:

(a) Listing in the City’s critical areas mapping resources as a wetland or resources listed in PMC 29.25.010(5);

(b) Documentation, through references in state or federal handbooks and/or reports by qualified experts;

(c) A finding by a qualified wetland biologist that an appropriate hydrologic, soil, and/or vegetation regime indicative of a wetland exists; or

(d) A reasonable belief by the Shoreline Administrator that a wetland may exist, supported by a site visit and subsequent consultation with a qualified wetland biologist.

(5) Wetland Detailed Study. Requirements. If a wetland detailed study is required, it shall meet the following requirements in addition to the basic requirements identified in PMC 29.25.020(10):

(a) The wetland detailed study shall be completed by a qualified wetlands biologist.

(b) The extent and boundaries of any wetlands shall be determined in accordance with the methodology specified under subsection (2) of this section. The boundary shall be surveyed and mapped at a scale no smaller than one inch equals 200 feet.

(c) A wetland community description and wetland classification shall be completed, consistent with the requirements of subsection (2) of this section.

(d) A written values and functions assessment shall be completed and address site hydrology (source of water in the system, water quality, flood and stream flow attenuation, seasonality of presence of water, if applicable), soils, vegetation, fish and wildlife habitat, recreation, and aesthetics.

(e) The site plan for the proposed activity shall be mapped at the same scale as the wetland map, showing the extent of the proposed activity in relationship to the surveyed wetland, including a detailed narrative describing the project, its relationship to the wetland, and its potential impact on the wetland.

(f) The proposed mitigation plan shall follow the general mitigation plan requirements described in PMC 29.25.020(13), and address how the activity has been mitigated to avoid and minimize adverse impacts to wetlands. The Wetland Mitigation in Washington State – Part 2: Developing Mitigation Plans, Department of Ecology Publication No. 06-06-011b, March 2006 (or any succeeding documents) should be used as a basis for mitigation.

(6) Wetland Detailed Study Exemptions. In addition to activities exempted in PMC 29.25.020(3) and PMC 29.35.080, the following activities shall not require a wetland detailed study, provided they are conducted using accepted BMPs as determined by the Shoreline Administrator:

(a) Conservation or preservation of soil, water, vegetation, fish, or other wildlife.

(7) Basic Wetland Requirement. A regulated wetland or its required buffer can only be altered if the wetland detailed study shows that:

(a) The proposed alteration does not degrade the quantitative and qualitative functions of the wetland and results in no net loss of ecological function, or

(b) Any degradation can be adequately mitigated to protect the wetland function. Any proposed alteration approved pursuant to this section shall include mitigation necessary to mitigate the impacts of the proposed alteration on the wetland as described in this section and PMC 29.25.020(13).

(8) Required Buffers.

(a) Buffer Requirements. The following buffers shall be required for wetlands based on the rating of the wetland as outlined in subsection (3) and land-use intensity described in Table 29.25.030(8)(b).

(i) 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.

Table 29.25.030(8)(a). Wetland Buffer Width Requirements

Wetland Characteristics

Buffer Width by Impact of Proposed Land Use

Other Measures Recommended for Protection

Category IV Wetlands (For wetlands scoring less than 16 points for all functions)

Score for all three basic functions is less than 16 points

Low – 25 feet

Moderate – 40 feet

High – 50 feet

No recommendations at this time

Category III Wetlands (For wetlands scoring 16 to 18 points or more for all functions)

Moderate level of function for habitat (score for habitat 5 to 7 points)

*If wetland scores 8 to 9 habitat points, use Category II buffers

Low – 75 feet

Moderate – 110 feet

High – 150 feet

No recommendations at this time

Score habitat for 3 to 4 points

Low – 40 feet

Moderate – 60 feet

High – 80 feet

No recommendations at this time

Category II Wetlands (For wetlands scoring 19 to 21 points or more for all functions or having the “Special Characteristics” identified in the rating system)

High level of function for habitat (score for habitat 8 to 9 points)

Low – 100 feet

Moderate – 150 feet

High – 200 feet

Maintain connections to other habitat areas

Moderate level of function for habitat (score for habitat 5 to 7 points)

Low – 75 feet

Moderate – 110 feet

High – 150 feet

No recommendations at this time

High level of function for water quality improvement and low for habitat (score for water quality 8 to 9 points; habitat less than 5 points)

Low – 50 feet

Moderate – 75 feet

High – 100 feet

No additional surface discharges of untreated runoff

Riparian forest

Buffer width to be based on score for habitat functions or water quality functions

Riparian forest wetlands need to be protected at a watershed or subbasin scale

Other protection based on needs to protect habitat and water quality functions

Not meeting above characteristic

Low – 50 feet

Moderate – 75 feet

High – 100 feet

No recommendations at this time

Vernal pool

Low – 100 feet

Moderate – 150 feet

High – 200 feet

Or develop a regional plan to protect the most important vernal pool complexes; buffers of vernal pools outside protection zones can then be reduced to:

Low – 40 feet

Moderate – 60 feet

High – 80 feet

No intensive grazing or tilling of wetland

Category I Wetlands (For wetlands scoring 22 points or more for all functions or having the “Special Characteristics” identified in the rating system)

Wetlands of high conservation value

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

High level of function for habitat (score for habitat 8 to 9 points)

Low – 100 feet

Moderate – 150 feet

High – 200 feet

Restore degraded parts of buffer

Maintain connections to other habitat areas

Moderate level of function for habitat (score for habitat 5 to 7 points)

Low – 75 feet

Moderate – 110 feet

High – 150 feet

No recommendations at this time

High level of function for water quality improvement (8 to 9 points) and low for habitat (less than 5 points)

Low – 50 feet

Moderate – 75 feet

High – 100 feet

No additional surface discharges of untreated runoff

Not meeting above characteristics

Low – 50 feet

Moderate – 75 feet

High – 100 feet

No recommendations at this time

Note:

See Table 29.25.030(8)(b) in this section, or as amended by Ecology, for types of land uses that can result in low, moderate, and high impacts to wetlands.

(b) The Land Use Intensity Table describes the types of proposed land use that can result in high, moderate, and low levels of impacts to adjacent wetlands.

Table 29.25.030(8)(b). Land Use Intensity Table

Level of Impact from Proposed Change in Land Use

Types of Land Use Based on Common Zoning Designations

High

• Commercial

• Urban

• Industrial

• Institutional

• Retail sales

• Residential (more than one unit/acre)

• Conversion to high-intensity agriculture (dairies, nurseries, greenhouses, growing and harvesting crops requiring annual tilling and raising and maintaining animals, etc.)

• High-intensity recreation (e.g., golf courses and ball fields)

• Hobby farms

Moderate

• Residential (1 unit/acre or less)

• Moderate-intensity open space (e.g., parks with biking and jogging)

• Paved driveways and gravel driveways serving three or more residences

• Paved trails

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

Low

• Forestry (cutting of trees only)

• Low-intensity open space (e.g., hiking, bird-watching, and preservation of natural resources)

• Unpaved trails

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

(c) Measuring Buffer Dimensions. Wetland buffers shall be measured horizontally in a landward direction from the delineated wetland edge.

(d) Wetlands Adjacent to Slopes. Where lands adjacent to a wetland display a continuous slope of 25 percent or greater, the buffer shall include such sloping areas. Where the horizontal distance of the sloping area is greater than the required standard buffer, the buffer shall be extended to a point 25 feet beyond the top of the bank of the sloping area.

(9) Buffer Width Modifications.

(a) Administrative Buffer Width Averaging. The required buffer widths established in this SMP may be modified by the Shoreline Administrator for a development on existing legal lots of record in place at the time of adoption of this SMP.

Buffer widths may be modified in accordance with the provisions of this section only where the applicant demonstrates all of the following:

(i) Averaging is necessary to avoid an extraordinary hardship to the applicant caused by circumstances peculiar to the property;

(ii) The designated buffer area contains variations in sensitivity to ecological impacts due to existing physical characteristics or the character of the buffer varies in slope, soils, or vegetation;

(iii) The total area contained within the buffer after averaging is no less than that contained within the standard buffer prior to averaging;

(iv) The minimum buffer width at its narrowest point shall not be less than 65 percent of the required buffer width established under this SMP; and

(v) The buffer width averaging does not result in a net loss of ecological function.

(b) Wetland Buffer Reductions.

(i) For wetlands that score moderate or high for habitat function, the width of the buffer can be reduced if the following criteria are met:

(A) A relatively undisturbed vegetative corridor of at least 100 feet in width is protected between the wetland and any other priority habitats; and

(B) The protected area is preserved by means of easement, covenant or other measure; and

(C) Measures identified in subsection (9)(b)(ii)(A) of this section are taken to minimize the impact of any proposed land use.

(ii) For wetlands that score low for habitat function, the buffer width can be reduced to that required for moderate land-use impacts by applying the following measures to minimize the impacts of the proposed land uses:

(A) Wetland buffers may be administratively modified based on reducing the intensity of impacts from land uses. Buffer widths required for high-intensity land uses may be reduced to those required for moderate land use intensity under the following conditions:

Direct lights away from the wetland and buffer.

Locate activities that generate noise away from the wetland and buffer.

Establish covenants limiting use of pesticides within 200 feet of a wetland.

Implement integrated pest-management programs.

Infiltrate or treat, detain and disperse runoff into buffer.

Post signs at the outer edge of the critical area or buffer to clearly indicate the location of the critical area according to the direction of the City.

Plant buffer with native vegetation appropriate for the region to create screens or barriers to noise, light, and human intrusion, as well as to discourage domestic animal intrusion.

Use low-impact development where appropriate.

Establish a permanent conservation easement to protect the wetland and the associated buffer.

(10) Compensatory Mitigation. As a condition of any development permit or approval, which results in on-site loss or degradation of regulated wetlands and/or wetland buffers, the City may require the applicant to provide compensatory mitigation to ensure no net loss of ecological function and to offset impacts resulting from the actions of the applicant. The following standards shall apply:

(a) The mitigation shall be conducted on property that shall be protected and managed to avoid further loss or degradation. The applicant shall provide for long-term preservation of the mitigation area.

(b) Mitigation ratios shall be consistent with the following entitled Washington State Department of Ecology manual; Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance (Version 1, Publication No. 06-06-011a, March 2006) and Wetland Mitigation in Washington State, Part 2: Developing Mitigation Plans (Version 1, Publication No. 06-06-011b, March 2006). See Table 29.25.030(13), Wetland Mitigation Ratios for Eastern Washington.

(c) Mitigation shall follow an approved mitigation plan and reflect the restoration/creation ratios specified above.

(d) The applicant shall enter in to a wetland mitigation monitoring agreement with the City as a condition of approval. The monitoring program will continue for at least eight years from the date of plant installation. Monitoring will continue for 10 years where woody vegetation (forested or shrub wetlands) is the intended result.

These communities take at least eight years after planting to reach 80 percent canopy closure. Reporting for a 10-year monitoring period shall occur in years 1, 2, 3, 5, 7, and 10. Monitoring in all instances shall be bonded. Reporting results of the monitoring data to the City is the responsibility of the applicant.

(e) Mitigation shall be completed prior to or concurrently with wetland loss, or, in the case of an enforcement action, prior to continuation of the activity by the applicant.

(f) On-site mitigation is generally preferred over off-site mitigation.

(g) Off-site mitigation allows replacement of wetlands away from the site on which the wetland has been impacted by a regulated activity. Off-site mitigation will be conducted in accordance with the restoration/creation ratios described above and in Table 29.25.030(13), Wetland Mitigation Ratios (for Eastern Washington). Off-site mitigation shall occur within the same drainage basin as the wetland loss occurs; provided, that Category IV wetlands may be replaced outside of the watershed if there is no reasonable alternative. Off-site mitigation may be permitted where:

(i) On-site mitigation is not feasible due to hydrology, soils, or other factors.

(ii) On-site mitigation is not practical due to probable adverse impacts from surrounding land uses or would conflict with a federal, state, or local public safety directive.

(iii) Potential functional values at the site of the proposed restoration are greater than the lost wetland functional values.

(h) When the wetland to be altered is of a limited functional value and is degraded, mitigation shall be of the wetland community types needed most in the location of mitigation and those most likely to succeed with the highest functional value possible.

(i) Except in the case of cooperative mitigation projects in selecting mitigation sites, applicants shall pursue locations in the following order of preference:

(i) Filled, drained, or cleared sites that were formerly wetlands and where appropriate hydrology exists.

(ii) Upland sites adjacent to wetlands, if the upland is significantly disturbed and does not contain a mature forested or shrub community of native species, and where the appropriate natural hydrology exists.

(j) Where out-of-kind replacement is accepted, greater restoration/creation ratios may be required.

(k) Construction of mitigation projects shall be timed to reduce impacts to existing wildlife and plants. Construction shall be timed to ensure that grading and soil movement occurs during the dry season, and planting of vegetation shall be specifically timed to the needs of target species.

(11) Innovative Mitigation.

(a) One or more applicants, or an organization may undertake a mitigation project together if it is demonstrated that all of the following circumstances exist:

(i) Creation of one or several larger wetlands may be preferable to many small wetlands;

(ii) The group demonstrates the organizational and fiscal capability to act cooperatively;

(iii) The group demonstrates that long-term management of the mitigation area will be provided; and

(iv) There is a clear potential for success of the proposed mitigation at the identified mitigation site.

(b) Wetland mitigation and banking programs shall be consistent with the provisions outlined in the Department of Ecology’s publication Wetland Mitigation in Washington State, Part 1: Agency Policies and Guidance (Version 1, Publication No. 06-06-011a, March 2006) and Wetland Mitigation in Washington State, Part 2: Developing Mitigation Plans (Version 1, Publication No. 06-06-01b, March 2006).

(i) 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 Shoreline Administrator determines 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.

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

(iii) 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, the service area of the bank may include portions of more than one adjacent drainage basin for specific wetland functions.

(12) Mitigation Exceptions. Requirements for mitigation do not apply when a wetland alteration is intended exclusively for the enhancement or restoration of an existing regulated wetland, and the proposal will not result in a loss of wetland function and value, subject to the following conditions:

(a) The enhancement or restoration project shall not be associated with a development activity.

(b) A restoration plan shall be prepared and approved as described in subsection (13) of this section.

(13) Restoration. Restoration is required when a wetland or its buffer has been altered in violation of this chapter. The following minimum performance standards shall be met for the restoration of a wetland; provided, that if it can be demonstrated by the applicant that greater functional and habitat values can be obtained, these standards may be modified:

(a) The original wetland configuration should be replicated, including depth, width, and length at the original location.

(b) The original soil types and configuration shall be replicated.

(c) The wetland, including buffer areas, shall be replanted with native vegetation, which replicates the original species, sizes, and densities.

(d) The original functional values shall be restored, including water quality and wildlife habitat functions.

(e) Required replacement ratios are shown in the Re-establishment or Creation column of Table 29.25.030(13), Wetland Mitigation Ratios for Eastern Washington.

(f) A restoration plan shall be prepared and approved prior to commencement of restoration work. Such a plan shall be prepared by a qualified wetland biologist and describe how the proposed actions meet the minimum requirements described above. The Shoreline Administrator shall, at the applicant’s expense, seek expert advice in determining the adequacy of the Restoration Plan. Inadequate plans shall be returned to the applicant for revision and resubmittal.

(14) Wetland mitigation ratios are provided in the Table 29.25.030(14).

Table 29.25.030(14). Wetland Mitigation Ratios for Eastern Washington

Category and Type of Wetland Impacts

Re-establishment or Creation

Rehabilitation Only1

Re-establishment or Creation and Rehabilitation1

Re-establishment or Creation and Enhancement1

Enhancement Only1

All Category IV

1.5:1

3:1

1:1 R/C and 1:1 RH

1:1 R/C and 2:1 E

6:1

All Category III

2:1

4:1

1:1 R/C and 2:1 RH

1:1 R/C and 4:1 E

8:1

All other Category II

3:1

6:1

1:1 R/C and 4:1 RH

1:1 R/C and 8:1 E

12:1

Category I based on score for functions

4:1

8:1

1:1 R/C and 6:1 RH

1:1 R/C and 12:1 E

16:1

Category I Natural Heritage site

Not considered possible2

6:1

Rehabilitation of a Natural Heritage site

R/C not considered possible2

R/C not considered possible2

Case-by-case

Notes:

1These ratios are based on the assumption that the rehabilitation or enhancement actions implemented represent the average degree of improvement possible for the site. Proposals to implement more effective rehabilitation or enhancement actions may result in a lower ratio, while less effective actions may result in a higher ratio. The distinction between rehabilitation and enhancement is not clear cut. Instead, rehabilitation and enhancement actions span a continuum. Proposals that fall within the gray area between rehabilitation and enhancement will result in a ratio that lies between the ratios for rehabilitation and the ratios for enhancement.

2Natural Heritage sites, alkali wetland, and bogs are considered irreplaceable wetlands because they perform some functions that cannot be replaced through compensatory mitigation. Impacts to such wetlands would therefore result in a net loss of some functions no matter what kind of compensation is proposed.

Reference:

Washington State Department of Ecology, U.S. Army Corps of Engineers Seattle District, and U.S. Environmental Protection Agency Region 10, March 2006. Wetland Mitigation in Washington State – Part 1: Agency Policies and Guidance (Version 1). Washington State Department of Ecology Publication No. 06-06-011a. Olympia, Washington (2006).

E = Enhancement

R/C = Re-establishment or Creation

RH = Rehabilitation

[Ord. 4314 § 2, 2016; Code 1970 § 29.01.520.]