Chapter 19.20
WETLANDS
Sections:
19.20.010 Designation, rating, and mapping wetlands.
19.20.020 Activities allowed in wetlands.
19.20.030 Critical areas report – Additional requirements for wetlands.
19.20.040 Performance standards – General requirements.
19.20.050 Performance standards – Compensatory mitigation requirements.
19.20.060 Performance standards – Subdivisions.
19.20.010 Designation, rating, and mapping wetlands.
A. Designating Wetlands. Wetlands are those areas, designated in accordance with the Washington State Wetland Identification and Delineation Manual (1997) or as revised, that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation adapted for life in saturated soil conditions. All areas within the City meeting the wetland designation criteria in the Identification and Delineation Manual, regardless of any formal identification, are hereby designated critical areas and are subject to the provisions of this title.
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 documents, 2004 revision, or as further 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:
i. Alkali wetlands;
ii. Wetlands of high conservation value;
iii. Bogs and calcareous fens;
iv. Mature and old-growth forested wetlands with slow growing trees;
v. Forests with stands of aspen; and
vi. Wetlands that perform functions at high levels (scores of 22 points or more).
These wetlands are those that (1) represent a unique or rare wetland type; (2) are more sensitive to disturbance than most wetlands; (3) are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime; or (4) provide a high level of function.
In using the rating system, the City will not consider wetlands that have one-quarter acre or more of forests with aspen as Category I unless they also meet some of the other criteria for a Category I wetland (see list above). Wetlands with stands of aspen are not considered to be rare in Spokane County or that they provide a unique habitat in short supply in the county.
b. Category II. Category II wetlands are:
i. Forested wetlands in the floodplains of rivers;
ii. Mature and old-growth forested wetlands with fast growing trees;
iii. Vernal pools; and
iv. Wetlands that perform functions well (scores between 19 and 21 points).
These wetlands are difficult, though not impossible, to replace, and provide high levels of some functions.
c. Category III. Category III wetlands are wetlands with a moderate level of functions (scores between 16 and 18 points) and can often be adequately replaced with a well-planned mitigation project. Wetlands scoring between 16 and 18 points generally have been disturbed in some ways and are often less diverse or 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 (scores less than 16 points) and are often heavily disturbed. These are wetlands that we should be able to replace and, in some cases, improve. However, experience has shown that replacement cannot be guaranteed in any specific case. These wetlands may provide some important functions, and also need to be protected.
C. Mapping. The exact location of a wetland’s boundary shall be determined through the performance of a field investigation by a qualified professional wetland scientist applying the Washington State Wetlands Identification and Delineation Manual as required by RCW 36.70A.175 (Ecology Publication No. 96-94, 1997). Additionally, soil maps produced by the U.S. Department of Agriculture National Resources Conservation Service may be useful in helping to identify potential wetland areas. (Ord. C-946 § 41, 2020; Ord. C-664 § 44, 2007)
19.20.020 Activities allowed in wetlands.
The activities listed below are allowed in wetlands in addition to those activities listed in, and consistent with, the provisions established in AHMC 19.10.160, Allowed activities, and do not require submission of a critical areas report, except where such activities result in a loss to the functions and values of a wetland or wetland buffer. These activities include:
A. Conservation or preservation of soil, water, vegetation, fish, shellfish, and other wildlife that does not entail changing the structure or functions of the existing wetland.
B. The harvesting of wild crops in a manner that is not injurious to natural reproduction of such crops and provided the harvesting does not require tilling of soil, planting of crops, chemical applications, or alteration of the wetland by changing existing topography, water conditions, or water sources.
C. Drilling for utilities under a wetland; provided, that the drilling does not interrupt the ground water connection to the wetland or percolation of surface water down through the soil column. Specific studies by a hydrologist are necessary to determine whether the ground water connection to the wetland or percolation of surface water down through the soil column is disturbed.
D. Enhancement of a wetland through the removal of normative invasive species. Weeding shall be restricted to hand removal and weed material shall be removed from the site. Bare areas that remain after weed removal shall be revegetated with native shrubs and trees at natural densities. Some hand seeding may also be done over the bare areas with native herbs. (Ord. C-946 § 42, 2020; Ord. C-664 § 45, 2007)
19.20.030 Critical areas report – Additional requirements for wetlands.
In addition to the general critical areas report requirements of AHMC 19.10.210, critical areas reports for wetlands must meet the requirements of this section. Critical areas reports for two or more types of critical areas must meet the report requirements for each relevant type of critical area.
A. Preparation by a Qualified Professional. A critical areas report for wetlands shall be prepared by a qualified professional who is a certified professional wetland scientist or a noncertified professional wetland scientist with a minimum of five years of experience in the field of wetland science and with experience preparing wetland reports.
B. Area Addressed in Critical Areas Report. The following areas shall be addressed in a critical areas report for wetlands:
1. The project area of the proposed activity;
2. All wetlands and recommended buffers within 300 feet of the project area; and
3. All shoreline areas, water features, and other critical areas, and related buffers within 300 feet of the project area.
C. Wetland Analysis. In addition to the minimum required contents of AHMC 19.10.210, Critical areas report – Requirements, a critical areas report for wetlands shall contain an analysis of the wetlands including the following site- and proposal-related information at a minimum:
1. A written assessment and accompanying maps of the wetlands and buffers within 300 feet of the project area, including the following information at a minimum:
a. Wetland delineation and required buffers;
b. Existing wetland acreage;
c. Wetland category;
d. Vegetative, faunal, and hydrologic characteristics;
e. Soil and substrate conditions;
f. Topographic elevations, at two-foot contours; and
g. A discussion of the water sources supplying the wetland and documentation of hydrologic regime (locations of inlet and outlet features, water depths throughout the wetland, evidence of recharge or discharge, evidence of water depths throughout the year – drift lines, algal layers, moss lines, and sediment deposits).
2. A discussion of measures, including avoidance, minimization, and mitigation, proposed to preserve existing wetlands and restore any wetlands that were degraded prior to the current proposed land use activity.
3. A habitat and native vegetation conservation strategy that addresses methods to protect and enhance on-site habitat and wetland functions.
4. Functional evaluation for the wetland and adjacent buffer using a local or state agency staff-recognized method and including the reference of the method and all data sheets.
5. Proposed mitigation, if needed, including a written assessment and accompanying maps of the mitigation area, including the following information at a minimum:
a. Existing and proposed wetland acreage;
b. Vegetative and faunal conditions;
c. Surface and subsurface hydrologic conditions, including an analysis of existing and future hydrologic regime and proposed hydrologic regime for enhanced, created, or restored mitigation areas;
d. Relationship within watershed and to existing water bodies;
e. Soil and substrate conditions, topographic elevations;
f. Existing and proposed adjacent site conditions;
g. Required wetland buffers (including any buffer reduction and mitigation proposed to increase the plant densities, remove weedy vegetation, and replant the buffers);
h. Property ownership; and
i. Associated wetlands and related wetlands that may be greater than 300 feet from the subject project.
6. A scale map of the development proposal site and adjacent area. A discussion of ongoing management practices that will protect wetlands after the project site has been developed, including proposed monitoring and maintenance programs.
7. A bond estimate for the installation (including site preparation, plant materials and installation, fertilizers, mulch, and stakes) and the proposed monitoring and maintenance work for the required number of years.
8. Title Notification. All activity in critical area protection areas shall be accompanied by a title.
D. Additional Information. When appropriate, the City Planner may also require the critical areas report to include an evaluation by the state Department of Ecology or an independent qualified expert regarding the applicant’s analysis and the effectiveness of any proposed mitigating measures or programs, and to include any recommendations as appropriate.
1. If the development proposal site contains or is within a wetland area, the applicant shall submit an affidavit which declares whether the applicant has knowledge of any illegal alteration to any or all wetlands on the proposed site and whether the applicant previously had been found in violation of this title. If the applicant has been found previously in violation, the applicant shall declare whether such violation has been corrected to the satisfaction of the jurisdiction.
2. The City Planner shall determine if the mitigation and monitoring plans and bonding measures proposed by the applicant are sufficient to protect the public health, safety, and welfare, consistent with the goals, purposes, objectives and requirements of this title. (Ord. C-946 § 43, 2020; Ord. C-664 § 46, 2007)
19.20.040 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 title.
C. Category II and III Wetlands. With respect to activities proposed in Category II and III wetlands, the following standards shall apply:
1. Water-dependent activities may be allowed where there are no practicable alternatives that would have a less adverse impact on the wetland, its buffers and other critical areas.
2. Where non-water-dependent activities are proposed, it shall be presumed that alternative locations are available, and activities and uses shall be prohibited, unless the applicant demonstrates that:
a. The basic project purpose cannot reasonably be accomplished and successfully avoid, or result in less adverse impact on, a wetland on another site or sites in the general region; and
b. All alternative designs of the project as proposed, that would avoid or result in less of an adverse impact on a wetland or its buffer, such as a reduction in the size, scope, configuration, or density of the project, are not feasible.
D. Wetland Buffers.
1. Buffer Requirements. The following buffer widths have been established in accordance with the best available science. They are based on the category of wetland and the 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, or as revised and approved by Ecology). The adjacent land use intensity is assumed to be high.
a. For wetlands that score five points or more for habitat function, the buffers in Table 19.20.040.1 can be used if both of the following criteria are met:
i. A relatively undisturbed, vegetated corridor at least 100 feet wide is protected between the wetland and any other priority habitat as defined by the Washington State Department of Fish and Wildlife (WDFW). The latest definitions of priority habitats and their locations are available on the WDFW website at:
http://wdfw.wa. gov/hab/phshabs.htm.
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.
Presence or absence of a nearby habitat must be confirmed by a qualified biologist. If no option for providing a corridor is available, Table 19.20.040.1 may be used with the required measures in Table 19.20.040.2 alone.
ii. The measures in Table 19.20.040.2 are implemented, where applicable, to minimize the impacts of the adjacent land uses.
b. For wetlands that score three to four habitat points, only the measures in Table 19.20.040.2 are required for the use of Table 19.20.040.1.
c. If an applicant chooses not to apply the mitigation measures in Table 19.20.040.2 or is unable to provide a protected corridor where available, then Table 19.20.040.3 must be used.
d. The buffer widths in Tables 19.20.040.1 and 19.20.040.3 assume that the buffer is vegetated with a native plant community appropriate for the ecoregion. If the existing buffer is not vegetated, 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.
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Buffer Width (in feet) Based on Habitat Score with Corridor Provided |
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Wetland Category |
3-4 |
5 |
6-7 |
8-9 |
|
Category I: Based on total score |
75 |
90 |
120 |
150 |
|
Category I: Forested |
75 |
90 |
120 |
150 |
|
Category I: Bogs and Wetlands of High Conservation Value |
190 |
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Category I: Alkali |
150 |
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|
Category II: Based on total score |
75 |
90 |
120 |
150 |
|
Category II: Vernal pool |
150 |
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Category II: Forested |
75 |
90 |
120 |
150 |
|
Category III (all) |
60 |
90 |
120 |
150 |
|
Category IV (all) |
40 |
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Disturbance |
Required Measures to Minimize Impacts |
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|---|---|---|---|---|
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Lights |
• Direct lights away from wetland. |
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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 ft. heavily vegetated buffer strip immediately adjacent to the outer buffer. |
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Toxic Runoff |
• Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered. • Establish covenants limiting the use of pesticides within 150 ft. of wetland. • Apply integrated pest management. |
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Storm Water Runoff |
• Retrofit storm water detention and treatment for roads and existing adjacent development. • Prevent channelized flow from lawns that directly enter the buffer. • Use low intensity development techniques. |
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Change in Water Regime |
• Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces and new lawns. |
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Pest 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 separate tract or protect with a conservation easement. |
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Dust |
• Use best management practices to control dust. |
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Buffer Width (in feet) Based on Habitat Score with Corridor not Provided |
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|---|---|---|---|---|
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Wetland Category |
3-4 |
5 |
6-7 |
8-9 |
|
Category I: Based on total score |
100 |
130 |
180 |
200 |
|
Category I: Forested |
100 |
130 |
180 |
200 |
|
Category I: Bogs and wetlands of high conservation value |
250 |
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|
Category I: Alkali |
200 |
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|
Category II: Based on total score |
100 |
130 |
180 |
200 |
|
Category II: Vernal pool |
200 |
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Category II: Forested |
100 |
130 |
180 |
200 |
|
Category III (all) |
80 |
130 |
180 |
200 |
|
Category IV (all) |
50 |
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2. Increased Wetland Buffer Widths. Buffer widths shall be increased on a case-by-case basis as determined by the City Planner when a larger buffer is necessary to protect wetland functions and values. This determination shall be supported by appropriate documentation showing that it is reasonably related to protection of the functions and values of the wetland. The documentation must include but not be limited to the following criteria:
a. The wetland is used by a state or federally listed plant or animal species or has essential or outstanding habitat for those species, or has unusual nesting or resting sites such as heron rookeries or raptor nesting trees; or
b. The adjacent land is susceptible to severe erosion, and erosion-control measures will not effectively prevent adverse wetland impacts; or
c. The adjacent land has minimal vegetative cover or slopes greater than 30 percent.
3. Buffer averaging to improve wetland protection may be permitted when all of the following conditions are met:
a. The wetland has significant differences in characteristics that affect its habitat functions, such as a wetland with a forested component adjacent to a degraded emergent component or a “dual-rated” wetland with a Category I area adjacent to a lower-rated area.
b. The buffer is increased adjacent to the higher-functioning area of habitat or more-sensitive portion of the wetland and decreased adjacent to the lower-functioning or less-sensitive portion as demonstrated by a critical areas report from a qualified wetland professional.
c. The total area of the buffer after averaging is equal to the area required without averaging.
d. The buffer at its narrowest point is never less than either three-quarters of the required width or 75 feet for Category I and II, 50 feet for Category III and 25 feet for Category IV, whichever is greater.
4. Averaging to allow reasonable use of a parcel may be permitted when all of the following are met:
a. There are no feasible alternatives to the site design that could be accomplished without buffer averaging.
b. The averaged buffer will not result in degradation of the wetland’s functions and values as demonstrated by a critical areas report from a qualified wetland professional.
c. The total buffer area after averaging is equal to the area required without averaging.
d. The buffer at its narrowest point is never less than either three-quarters of the required width or 75 feet for Category I and II, 50 feet for Category III and 25 feet for Category IV, whichever is greater.
5. Buffers on Mitigation Sites. All wetland mitigation sites shall have buffers consistent with the buffer requirements of this chapter. Buffers shall be based on the expected or target category of the proposed wetland mitigation site.
6. Buffer Maintenance. Except as otherwise specified or allowed in accordance with this chapter, wetland buffers shall be retained in an undisturbed or enhanced condition. In the case of compensatory mitigation sites, removal of invasive non-native weeds is required for the duration of the mitigation bond (AHMC 19.10.400).
7. Impacts to Buffers. Requirements for the compensation for impacts to buffers are outlined in AHMC 19.20.050(C).
8. Overlapping Critical Area Buffers. If buffers for two contiguous critical areas overlap (such as buffers for a stream and a wetland), the wider buffer applies.
9. Allowed Buffer Uses. The following uses may be allowed 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 and in accordance with an approved critical area report, including:
i. Walkways and trails; provided, that those pathways are limited to minor crossings having no adverse impact on water quality. They should be generally parallel to the perimeter of the wetland, located only in the outer 25 percent of the wetland buffer area, and located to avoid removal of significant trees. They should be limited to pervious surfaces no more than five feet in width for pedestrian use only. Raised boardwalks utilizing non-treated pilings may be acceptable.
ii. Wildlife-viewing structures.
c. Educational and scientific research activities.
d. Normal and routine maintenance and repair of any existing public or private facilities within an existing right-of-way; provided, that the maintenance or repair does not increase the footprint or use of the facility or right-of-way.
e. The harvesting of wild crops in a manner that is not injurious to natural production of such crops and provided the harvesting does not require tilling of soil, planting of crops, chemical applications, or alteration of the wetland by changing existing topography, water conditions, or water sources.
f. Drilling for utilities/utility corridors under a buffer, with entrance/exit portals located completely outside of the wetland buffer boundary; provided, that the drilling does not interrupt the ground water connection to the wetland or percolation of surface water down through the soil column. Specific studies by a hydrologist are necessary to determine whether the ground water connection to the wetland or percolation of surface water down through the soil column is disturbed.
g. Enhancement of a wetland buffer through the removal of non-native invasive plant species. Removal of invasive plant species shall be restricted to hand removal. All removed plant material shall be taken away from the site and appropriately disposed of. Plants that appear on the Washington State Noxious Weed Control Board list of noxious weeds must be handled and disposed of according to a noxious weed control plan appropriate to that species. Revegetation with appropriate native species at natural densities is allowed in conjunction with removal of invasive plant species.
h. Repair and maintenance of nonconforming uses or structures where legally established within the buffer, provided they do not increase the degree of nonconformity.
10. Signs and Fencing of Wetlands.
a. Temporary Markers. The outer perimeter of the wetland or 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. This temporary marking shall be maintained throughout construction and shall not be removed until permanent signs, if required, are in place.
b. Permanent Signs. As a condition of any permit or authorization issued pursuant to this chapter, the City Planner may require the applicant to install permanent signs along the boundary of a wetland or buffer.
i. Permanent signs shall be made of an enamel-coated metal face and attached to a metal post, or another nontreated material of equal durability, Signs must be posted at an interval of one per lot or every 50 feet, whichever is less, and must be maintained by the property owner in perpetuity. The sign shall be worded as follows or with alternative language approved by the City Planner:
Protected Wetland Area
Do Not Disturb
Contact the City of Airway Heights
Regarding Uses and Restriction
ii. The provisions of subsection (D)(10)(b)(i) of this section may be modified as necessary to assure protection of sensitive features or wildlife.
11. Fencing.
a. The City Planner shall determine if fencing is necessary to protect the functions and values of the critical area. If found to be necessary, the City Planner shall condition any permit or authorization issued pursuant to this chapter to require the applicant to install a permanent fence at the edge of the wetland buffer, when fencing will prevent future impacts to the wetland.
b. The applicant shall be required to install a permanent fence around the wetland or buffer when domestic grazing animals are present or may be introduced on site.
c. Fencing installed as part of a proposed activity or as required in this subsection shall be designed so as to not interfere with species migration, including fish runs, and shall be constructed in a manner that minimizes impacts to the wetland and associated habitat.
12. Applicant must submit a sign permit application. (Ord. C-946 § 44, 2020; Ord. C-664 § 47, 2007)
19.20.050 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’s 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).
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 Lost or Affected Functions. 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, 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 significantly degraded wetlands in combination with restoration or creation. Such enhancement should be part of a mitigation package that includes replacing the impacted area and 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, sub-basin, 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, 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, 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 City Planner 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 that 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 restoration 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. The first number specifies the acreage of replacement wetlands and the second specifies the acreage of wetlands altered.
a. Category III: two-to-one.
2. Increased Replacement Ratio. The City Planner 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. Wetlands Enhancement as Mitigation.
1. Impacts to wetland functions may be mitigated by enhancement of existing significantly degraded wetlands but must be used in conjunction with restoration and/or creation. Applicants proposing to enhance wetlands must produce a critical areas report that identifies how enhancement will increase the functions of the degraded wetland and how this increase will adequately mitigate for the loss of wetland area and function at the impact site. An enhancement proposal must also show whether existing wetland functions will be reduced by the enhancement actions.
2. At a minimum, enhancement acreage shall be double the acreage required for creation or restoration under subsection (G) of this section. The ratios shall be greater than double the required acreage where the enhancement proposal would result in minimal gain in the performance of wetland functions and/or result in the reduction of other wetland functions currently being provided in the wetland.
3. Mitigation ratios for enhancement in combination with other forms of mitigation shall range from 6:1 to 3:1 and be limited to Class III and Class IV wetlands.
H. 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 City Planner 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. C-946 § 45, 2020; Ord. C-664 § 48, 2007)
19.20.060 Performance standards – Subdivisions.
The subdivision and short subdivision of land in wetlands and associated buffers is subject to the following:
A. Land that is located wholly within a wetland or its buffer may not be subdivided.
B. Land that is located partially within a wetland or its buffer may be subdivided; provided, that an accessible and contiguous portion of each new lot:
1. Is located outside of the wetland and its buffer; and
2. Meets the minimum lot size requirements of AHMC Title 17, Zoning.
C. Access roads and utilities serving the proposed subdivision may be permitted within the wetland and associated buffers only if the City determines that no other feasible alternative exists and when consistent with this title. (Ord. C-946 § 46, 2020; Ord. C-664 § 49, 2007)