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. Airway Heights only has manmade Category III wetlands, excluding wetlands on tribal ground. See the 2007 critical areas inventory for more information. The Spokane Tribe currently has no known wetlands in the City or urban growth area and may have more information after their environmental impact statement is complete. Per the National Wetlands Inventory, the Kalispel Tribe has three small wetlands, but no wetland plants or hydric soils were found and the site was determined not to contain wetlands.
1. Wetland Rating Categories.
a. Category I. Category I wetlands are:
i. Alkali wetlands;
ii. Wetlands that are identified by scientists of the Washington Natural Heritage Program/DNR as high-quality wetlands;
iii. Bogs;
iv. Mature and old-growth forested wetlands over one-quarter acre with slow-growing trees;
v. Forests with stands of aspen; and
vi. Wetlands that perform many functions very well (scores of 70 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 over one-quarter acre with fast-growing trees;
iii. Vernal pools; and
iv. Wetlands that perform functions well (scores between 51 and 69 points).
These wetlands are difficult, though not impossible, to replace, and provide high levels of some functions.
c. Category III. Category III wetlands are:
i. Vernal pools that are isolated; and
ii. Wetlands with a moderate level of functions (scores between 30 and 50 points).
d. Category IV. Category IV wetlands have the lowest level of functions (scores less than 30 points) and are often heavily disturbed. These are wetlands that we should be able to replace and in some cases be able to 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 approximate location and extent of wetlands are shown on the adopted critical area maps. 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.
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’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). (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 nonnative 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-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-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. Standard Buffer Widths. The standard buffer widths presume the existence of a relatively intact native vegetation community in the buffer zone adequate to protect the wetland functions and values at the time of the proposed activity. If the vegetation is inadequate, then the buffer width shall be increased or the buffer should be planted to maintain the standard width. Airway Heights only has manmade Category III wetlands. See the 2007 critical areas inventory for more information.
a. Category III: 75 feet.
2. 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 and the proposed land use. 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.
3. Increased Wetland Buffer Widths. The City Planner shall require increased buffer widths in accordance with the recommendations of an experienced, qualified professional wetland scientist and the 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. 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; or
c. The buffer area has minimal vegetative cover. In lieu of increasing the buffer width where existing buffer vegetation is inadequate to project 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.
4. Wetland Buffer Width Averaging. The City Planner may allow modification of the standard wetland buffer width in accordance with an approved critical areas 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.
5. Buffer Consistency. All mitigation sites shall have buffers consistent with the buffer requirements of this chapter.
6. Buffer Maintenance. Except as otherwise specified or allowed in accordance with this title, wetland buffers shall be retained in an undisturbed or enhanced condition. Removal of invasive nonnative weeds is required for the duration of the mitigation bond.
7. Buffer Uses. The following uses may be permitted within a wetland buffer in accordance with the review procedures of this title; 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 areas report, including:
i. Walkways and trails; provided, that those pathways that 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 areas 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. Storm Water Management Facilities. Storm water management facilities, limited to storm water 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.
iii. Storm water management facilities are not allowed in buffers of Category I or II wetlands.
E. Signs and Fencing of Wetlands.
1. 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.
2. 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.
a. 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
b. The provisions of subsection (E)(2)(a) of this section may be modified as necessary to assure protection of sensitive features or wildlife.
3. 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 (E)(3) 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.
4. Applicant must submit a sign permit application. (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 the 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-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-664 § 49, 2007)