Chapter 18.60 CRITICAL AREAS REGULATIONS

The purpose of this chapter is to implement the goals and policies of the Washington State Growth Management Act, and specifically RCW 36.70A.060, which requires each local jurisdiction to adopt rules for protection of environmentally critical areas. This chapter also implements elements of the Washington State Environmental Policy Act, Chapter 43.21C RCW, and the Maple Valley comprehensive plan which call for protection of the natural environment and the public health and safety. The provisions of this chapter are designed to accomplish the following:

A. Establishing development standards to protect defined critical areas;

B. Protecting members of the public and public resources and facilities from injury, loss of life, property damage or financial loss due to flooding, erosion, landslides, seismic events, soil subsidence or steep slope failures;

C. Protecting unique, fragile and valuable elements of the environment including, but not limited to, wildlife and its habitat;

D. Requiring mitigation of unavoidable impacts on environmentally critical areas by regulating alterations in or near critical areas;

E. Preventing cumulative adverse environmental impacts on water availability, water quality, ground water, wetlands and streams;

F. Measuring the quantity and quality of wetland and stream resources and preventing overall net loss of wetland and stream functions;

G. Protecting the public trust as to navigable waters and aquatic resources;

H. Alerting members of the public including, but not limited to, appraisers, owners, potential buyers or lessees to the development limitations of critical areas; and

I. Providing City officials with sufficient information to protect critical areas. (Ord. O06-333 § 1).

18.60.020 Applicability.

A. The provisions of this chapter shall apply to all land uses in the City of Maple Valley, and all persons, projects or agencies within the City shall comply with the requirements of this chapter.

B. The City of Maple Valley shall not approve any permit or otherwise issue any authorization to alter the condition of any land, water or vegetation or to construct or alter any structure or improvement without first assuring compliance with the requirements of this chapter.

C. Approval of a development proposal pursuant to the provisions of this chapter does not discharge the obligation of the applicant to comply with the provisions of this chapter.

D. When any provision of any other chapter of the Maple Valley Municipal Code conflicts with this chapter or when the provisions of this chapter are in conflict, that provision which provides more protection to environmentally critical areas shall apply unless specifically provided otherwise in this chapter or unless such provision conflicts with federal or State laws or regulations.

E. The provisions of this chapter shall apply to all forest practices over which the City has jurisdiction pursuant to Chapter 76.09 RCW and WAC Title 222. (Ord. O-06-333 § 1).

18.60.030 Definitions.

A. “A” Definitions.

1. “Anadromous fish” is a life history strategy of certain fish (e.g., salmon) where rearing occurs in saltwater and spawning occurs in freshwater.

B. “B” Definitions.

1. “Best available science (BAS)” means current scientific information used in the process of designating, protecting, or restoring critical areas; that is, scientific information derived from a valid scientific process as defined by WAC 365-195-900 through 365-195-925.

2. “Buffer or buffer area” means vegetated areas adjacent to wetlands or other aquatic resources that can reduce impacts from adjacent land uses through various physical, chemical, and/or biological processes.

C. “C” Definitions.

1. “Channel migration zone” (CMZ) means the area within which a river channel is likely to migrate and occupy over a specified time period (e.g., 100 years).

2. “Compensatory mitigation” means the restoration (reestablishment or rehabilitation), establishment (creation), enhancement, and/or certain circumstances for the preservation of wetlands for the purposes of offsetting unavoidable adverse impacts that remain after all appropriate and practicable avoidance and minimization has been achieved.

3. “Critical areas” means any of those areas which are subject to natural hazards or those land features which support unique, fragile or valuable natural resources including fishes, wildlife and other organisms and their habitat and such resources which carry, hold or purify water in their natural state. Critical areas include geologically hazardous areas (coal mine hazard areas, erosion hazard areas, landslide hazard areas, seismic hazard areas, steep slope hazard areas), flood hazard areas, critical aquifer recharge areas, streams, fish and wildlife habitat conservation areas, and wetlands.

4. “Critical aquifer recharge areas” (CARA) means those areas with a critical recharging effect on aquifers used for potable water, including areas where an aquifer that is a source of drinking water is vulnerable to contamination that would affect the potability of the water, or is susceptible to reduced recharge (WAC 365-190-030(3), 365-190-100). CARA include:

a. Those areas that have prevailing geologic conditions associated with infiltration rates that create a high potential for contamination of ground water resources or contribute significantly to the replenishment of ground water.

b. Wellhead protection areas (WHPA) defined by the boundaries of the six-month, one-, five- and 10-year time of ground water travel, or boundaries established using alternate criteria approved by the Department of Health in those settings where ground water time of travel is not a reasonable delineation criterion, in accordance with WAC 246-290-135.

c. Those critical aquifer recharge areas delineated by a hydrogeologic study prepared in accordance with the state Department of Ecology guidelines.

d. Susceptible ground water management areas as designated pursuant to Chapters 173-100 WAC.

e. Special protection areas as defined by WAC 173-200-090.

f. Those aquifer recharge areas meeting the criteria for susceptibility or vulnerability established by the state Department of Ecology.

g. Sole source aquifers as designated by the U.S. Environmental Protection Agency under the Sole Source Aquifer Protection Plan authorized by Section 1424(e) of the Safe Drinking Water Act of 1974.

h. Other areas listed in WAC 365-190-100(4).

5. “Critical habitat” means specific geographic areas that contain features essential to the conservation of an endangered or threatened species and may require special management and protection. Critical habitat may also include areas that are not currently occupied by the species but are needed for its recovery.

6. “Creation” means the manipulation of the physical, chemical, or biological characteristics present to develop a wetland that did not previously exist at an upland site. Creation results in a gain in wetland area and functions. A typical action is the excavation of upland soils to elevations that will produce a wetland hydroperiod and hydric soils and support the growth of hydrophytic plant species.

7. “Cumulative impacts” means the combined, incremental effects of human activity on critical area functions and values. Cumulative impacts result when the effects of an action are added to or interact with the effects of other actions in a particular place and within a particular time. It is the combination of these effects, and any resulting environmental degradation, which should be the focus of cumulative impact analysis and changes to policies and permitting decisions.

D. “D” Definitions.

1. “Development” means a land use consisting of the construction or exterior alteration of structures; grading, dredging, drilling, or dumping; filling; removal of sand, gravel or minerals; bulkheading; driving of pilings; or any project of a temporary or permanent nature that modifies structures, land, wetlands, buffers, or shoreline and that does not fall within the allowable exemptions or exceptions contained in the Maple Valley Code.

2. “Director” means the Director of the Community Development Department or designee.

E. “E” Definitions.

1. “Ecosystem functions” are the products, physical and biological conditions, and environmental qualities of an ecosystem that result from interactions among ecosystem processes and ecosystem structures. Ecosystem functions include, but are not limited to, sequestered carbon, attenuated peak streamflows, aquifer water level, reduced pollutant concentrations in surface and ground waters, cool summer in-stream water temperatures, and fish and wildlife habitats.

2. “Ecosystem values” are the cultural, social, economic, and ecological benefits attributed to ecosystem functions.

3. “Enhancement” means the manipulation of the physical, chemical, or biological characteristics of a wetland to heighten, intensify, or improve specific function(s). Enhancement results in the gain of selected function(s) but may also lead to a decline in other function(s). Enhancement does not result in a gain in wetland area.

4. “Erosion” (see also “geologically hazardous areas”) means the process by which soil particles are mobilized and transported by natural agents such as wind, rainsplash, frost action or surface water flow.

5. “Erosion hazard areas” means those areas underlain by soils which are subject to severe erosion when disturbed. Such soils include, but are not limited to, those classified as having a severe to very severe erosion hazard according to the USDA Natural Resources Conservation Service, These soils include, but are not limited to, any occurrence of River Wash (“Rh”) or Coastal Beaches (“Cb”) and the following when they occur on slopes 15 percent or steeper: Alderwood Gravelly Sandy Loam (AgD), Alderwood and Kitsap (AkF), Beausite Gravelly Sandy Loam (BeD and BeF), Ovall Gravelly Loam (OvD and OvF), Ragnar Fine Sandy Loam (RaD), and Ragnar-Indianola association (RdE).

F. “F” Definitions.

1. “Fish and wildlife habitat conservation area” means land management for maintaining populations of species in suitable habitats within their natural geographic distribution so that the habitat available is sufficient to support viable populations over the long term and isolated subpopulations are not created. Fish and wildlife habitat conservation areas do not include such artificial features or constructs as irrigation delivery systems, irrigation infrastructure, irrigation canals, or drainage ditches that lie within the boundaries of and are maintained by a port district or an irrigation district or company.

Fish and wildlife habitat conservation areas include:

a. Areas where endangered, threatened, and sensitive species have a primary association;

b. Habitats and species of local importance;

c. Naturally occurring ponds do not include ponds deliberately designed and created from dry sites, such as canals, detention facilities, wastewater treatment facilities, farmponds, temporary construction ponds (of less than three years duration) and landscape amenities. However, naturally occurring ponds may include those artificial ponds intentionally created from dry areas in order to mitigate conversion of ponds, if permitted by a regulatory authority;

d. Waters of the State, as defined in RCW 90.48.020.

e. Lakes, ponds, streams, and rivers planted with game fish by a governmental or tribal entity.

f. Areas in which State-listed priority habitats and species are found, have a primary association with, or contain suitable habitat for said listed species, as referenced in the most updated version of the Washington Department of Fish and Wildlife’s Priority Habitats and Species (PHS) list and shown on the corresponding PHS map.

2. “Flood hazard areas” (also known as frequently flooded areas) means those areas subject to a general and temporary condition of partial or complete inundation of normally dry land areas from:

a. The overflow of inland waters and/or

b. The unusual and rapid accumulation of runoff of surface waters from any source.

3. “Functions and values” means the ecosystem services provided by critical areas to society, including, but not limited to, improving water quality, providing fish and wildlife habitat, supporting terrestrial and aquatic food chains, reducing flooding and erosive flows, wave attenuation, carbon sequestration, thermal refugia, historical or archaeological importance, cultural uses and significance, education opportunities, and recreation.

G. “G” Definitions.

1. “Geologically hazardous areas” means areas that because of their susceptibility to erosion, sliding, earthquake, or other geological events, are not suited to the siting of commercial, residential, or industrial development consistent with public health or safety concerns. These include areas susceptible to erosion, sliding, earthquake, or other geological events. Areas that are susceptible to one or more of the following types of hazards shall be classified as geological hazardous areas: erosion hazard, steep slope hazard area, landslide hazard, and seismic hazard (WAC 365-190-120).

H. “H” Definitions.

1. “Hazardous substance processing or handling” means the use, storage, manufacture, or other land use activity involving hazardous substances, but does not include individually packaged consumer products or quantities of hazardous substances less than five gallons in volume per container. Hazardous substances shall not be disposed on-site unless in compliance with Dangerous Waste Regulations, Ch. 173-303 WAC, and any pertinent local ordinances, such as sewer discharge standards.

2. “Hazardous waste” means and includes all dangerous waste and extremely hazardous waste as designated pursuant to Chapter 70.105 RCW and Chapter 173-303 WAC.

a. “Dangerous waste” means any discarded, useless, unwanted or abandoned substances including, but not limited to, certain pesticides, or any residues or containers of such substances which are disposed of in such quantity or concentration as to pose a substantial present or potential hazard to human health, wildlife, or the environment because such wastes or combinations of such wastes:

i. Have short-lived, toxic properties that may cause death, injury, or illness or have mutagenic, teratogenic, or carcinogenic properties; or

ii. Are corrosive, explosive, flammable, or may generate pressure through decomposition or other means.

b. “Extremely hazardous waste” means any waste which:

i. Will persist in a hazardous form for several years or more at a disposal site and which in its persistent form presents a significant environmental hazard and may be concentrated by living organisms through a food chain or may affect the genetic make-up of humans or wildlife, and

ii. Is disposed of at a disposal site in such quantities as would present an extreme hazard to humans or the environment.

I. “I” Definitions.

1. “Impermeable” means not permitting passage (as of a fluid) through its substance.

2. “Impervious surface” means a surface area that either prevents or retards the entry of water into the soil or other substrate that would occur under natural conditions prior to development. A non-vegetated surface area that causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under predevelopment or predeveloped conditions. Common impervious surfaces include, but are not limited to, rooftops; walkways; patios; driveways; parking lots; storage areas; concrete or asphalt paving; gravel roads; packed earthen materials; and oiled macadam, or other surfaces that similarly impede the natural infiltration of stormwater.

J. “J” Definitions. Reserved.

K. “K” Definitions. Reserved.

L. “L” Definitions.

1. “Landslide” means episodic downslope movement of a mass including, but not limited to, vegetation, soil and rock.

2. “Landslide hazard area” (see also “geologically hazardous areas”) means those areas subject to severe risks of landslides. The areas are subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include any areas susceptible to landslide because of any combination of bedrock, soil, slope (gradient), slope aspect, structure, hydrology, or other factors, including the following:

a. Area with all three of the following characteristics:

i. Slopes steeper than 15 percent;

ii. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock; and

iii. Springs or ground water seepage;

b. Any area which has shown movement during the Holocene epoch, from 10,000 years ago to the present, or which is underlain by mass wastage debris from that epoch;

c. Any area potentially unstable as a result of rapid stream incision, stream bank erosion or undercutting by wave action including stream channel migration zones; or

d. Any area located in a canyon or active alluvial fan, presently subject to or potentially subject to inundation by debris flows or catastrophic flooding.

e. Areas of historic failures, such as:

i. Those areas delineated by the United States Department of Agriculture Natural Resources Conservation Service as having a significant limitation for building site development;

ii. Areas designated as quaternary slumps, earthflows, mudflows, lahars or landslides on maps published by the United States Geological Survey or Washington Department of Natural Resources.

f. Slopes that are parallel or subparallel to planes of weakness (such as bedding planes, joint systems, and fault planes) in subsurface materials;

g. Slopes having gradients steeper than 80 percent subject to rockfall during seismic shaking;

M. “M” Definitions. Reserved.

N. “N” Definitions.

1. “Native vegetation” means plant species that occur naturally in a particular region or environment and were present before European colonization.

2. “Non-federally regulated wetland” means a wetland that is not jurisdictional under the federal Clean Water Act. Sometimes referred to as “isolated wetlands,” these wetlands remain regulated under State and local laws and rules, whether or not they are protected by federal law.

O. “O” Definitions.

1. “Ordinary high water mark” means the mark that will be found by examining the bed and banks and ascertaining where the presence and action of waters are so common and unusual, and so long continued in all ordinary years, as to mark upon the soil a character distinct from that of the abutting upland, in respect to vegetation as that condition exists on June 1, 1971, as it may naturally change thereafter, or as it may change thereafter in accordance with permits issued by the City of Maple Valley or the Department of Ecology.

P. “P” Definitions.

1. “Preservation” means the removal of a threat to, or preventing the decline of, wetland conditions by an action in or near a wetland. This term includes activities commonly associated with the protection and maintenance of wetlands through the implementation of appropriate legal and physical mechanisms (such as recording conservation easements and providing structural protection like fences and signs). Preservation does not result in a gain of wetland area and functions (but may result in a gain in functions over the long term).

2. “Priority habitats” are (as defined by WDFW) habitat types or elements with unique or significant value to a diverse assemblage of species. A priority habitat may consist of a unique vegetation type (e.g., shrub-steppe) or dominant plant species (e.g., juniper savannah), a described successional stage (e.g., old growth forest), or a specific habitat feature (e.g., cliffs).

3. “Priority species” are (as defined by WDFW) State Endangered, Threatened, Sensitive and Candidate species; animal aggregations (e.g., heron colonies, bat colonies) considered vulnerable; and species of recreational, commercial, or tribal importance that are vulnerable.

Q. “Q” Definitions.

1. “Qualified professional,” for purposes of Chapter 18.60 MVMC, means a person with experience and training in the applicable critical area. A qualified professional must have obtained a B.S. or B.A. or equivalent degree in biology, engineering, environmental studies, fisheries, geomorphology or related field, and two years of related work experience.

a. A qualified professional for watercourses, wetlands, and fish and wildlife habitat conservation areas must have a degree in biology or related field and relevant professional experience.

b. A qualified professional for preparing geotechnical reports and geotechnical design recommendations must be a professional geotechnical engineer, licensed in the State of Washington, as defined under WAC 16-210-010(5). Identification and evaluation of geologic hazards may be performed by geologists or other geology professionals with experience identifying geologic hazards.

R. “R” Definitions.

1. “Reestablishment” means the manipulation of the physical, chemical, or biological characteristics of a site with the goal of returning natural/historic functions and environmental processes to a former aquatic resource. Re-establishment results in rebuilding a former aquatic resource and results in a gain in aquatic resource area and functions.

2. “Rehabilitation” means the manipulation of the physical, chemical, or biological characteristics of a site with the goal of repairing natural/historic functions (and environmental processes) to a degraded aquatic resource. Rehabilitation results in a gain in aquatic resource function but does not result in a gain in aquatic resource areas.

3. “Repair or maintenance” means an activity that restores the character, scope, size and design of a serviceable area, structure, or land use to its previously authorized and undamaged condition. Activities that change the character, size or scope of a project beyond the original design and drain, dredge, fill, flood, or otherwise alter critical areas are not included in this definition.

4. “Restoration” means the manipulation of the physical, chemical, or biological characteristics of a site with the goal of returning natural/historic functions (and environmental processes) to a former or degraded aquatic resource. For the purpose of tracking net gains in aquatic resource area, restoration is divided into two categories: reestablishment and rehabilitation.

S. “S” Definitions.

1. “Seismic hazard areas” (see also “geologically hazardous areas”) means those areas subject to severe risk of earthquake induced ground shaking, slope failure, settlement or subsidence, soil liquefaction, surface faulting, or tsunamis. Settlement and soil liquefaction conditions occur in areas underlain by cohesionless soils of low density typically in association with a shallow groundwater table. One indicator of potential for future earthquake damage is a record of earthquake damage in the past. Ground shaking is the primary cause of earthquake damage in Washington, and ground settlement may occur with shaking.

2. “Species, listed” means any species listed under the federal Endangered Species Act or listed as State endangered, threatened and sensitive (see WAC 220-610-110 or current “Priority Habitat and Species List,” Washington Department of Fish and Wildlife).

3. “Steep slope hazard areas” (see also “geologically hazardous areas”) means those areas on slopes 40 percent or steeper within a vertical elevation change of at least 10 feet. A slope is delineated by establishing its toe and top and is measured by averaging the inclination over at least 10 feet of vertical relief. For the purpose of this definition:

a. The toe of a slope is a distinct topographic break in slope which separates slopes inclined at less than 40 percent from slopes 40 percent or steeper. Where no distinct break exists, the toe of a steep slope is the lowermost limit of the area where the ground surface drops 10 feet or more vertically within a horizontal distance of 25 feet; and

b. The top of a slope is a distinct, topographic break in slope which separates slopes inclined at less than 40 percent from slopes 40 percent or steeper. Where no distinct break exists, the top of a steep slope is the upper most limit of the area where the ground surface drops 10 feet or more vertically within a horizontal distance of 25 feet.

4. “Streams” mean an area where open surface water produces a defined channel or bed, not including irrigation ditches, canals, storm or surface water runoff devices, or other entirely artificial watercourses, unless they are used by salmonids or are used to convey a watercourse that was naturally occurring prior to construction. A channel or bed need not contain water year-round, provided there is evidence of at least intermittent flow during years of normal rainfall.

Streams are classified according to the following types:

Type	Description
Type “S” – Shoreline	Streams and waterbodies that are designated “shorelines of the state” as defined in RCW 90.58.030.
Type “F” – Fish	Streams and waterbodies that are known to be used by fish or meet the physical criteria to be potentially used by fish. Fish streams may or may not have flowing water all year; they may be perennial or seasonal.
Type “Np” – Non-Fish	Streams that have flow year-round and may have spatially intermittent dry reaches downstream of perennial flow. Type Np streams do not meet the physical criteria of a Type F stream. This also includes streams that have been proven not to contain fish using methods described in Forest Practices Board Manual Section 13.
Type “NS” – Non-Fish Seasonal	Streams that do not have surface flow during at least some portion of the year, and do not meet the physical criteria of a Type F stream.

5. “Stream functions” means natural processes performed by streams including functions which are important in facilitating food chain production, providing habitat for nesting, rearing and resting sites for aquatic, terrestrial and avian species, maintaining the availability and quality of water, such as purifying water, acting as recharge and discharge areas for groundwater aquifers, moderating surface and stormwater flows and maintaining the free flowing conveyance of water, sediments and other organic matter.

T. “T” Definitions. Reserved.

U. “U” Definitions.

1. “Unavoidable impacts” means adverse impacts that remain after all appropriate and practicable avoidance and minimization has been achieved.

V. “V” Definitions. Reserved.

W. “W” Definitions.

1. “Wellhead protection zone” means a zone designated under guidance from the Washington Department of Health Wellhead Protection Program pursuant to Chapter 246-290 WAC to protect areas with a critical recharging effect on aquifers used for potable waters.

2. “Wetlands” means those areas which are inundated or saturated by ground or surface water at a frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.

Wetlands generally include swamps, marshes, bogs and similar areas, or other artificial features intentionally created to mitigate conversions of wetlands pursuant to wetlands mitigation banking.

Wetlands do not include artificial features created from nonwetland areas including, but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds and landscape amenities, or those wetlands created after July 1, 1990, that were unintentionally created as a result of the construction of a road, street, or highway.

Where the vegetation has been removed or substantially altered, a wetland shall be determined by the presence or evidence of hydric or organic soil, as well as by other documentation, such as aerial photographs, of the previous existence of wetland vegetation.

3. “Wetland delineation” means the method used to establish the existence (location) and physical limits (size) of a wetland for purposes of federal, State, and local regulations.

4. “Wetland edge” means the line delineating the outer edge of a wetland, consistent with the approved federal wetland delineation manual and applicable regional supplement.

5. “Wetland functions” means natural processes performed by wetlands including functions which are important in facilitating food chain production, providing habitat for nesting, rearing and resting sites for aquatic, terrestrial and avian species, maintaining the availability and quality of water, acting as recharge and discharge areas for groundwater aquifers and moderating surface and stormwater flows, as well as performing other functions including, but not limited to, those set forth in 33 CFR 320.4(b)(2), 1988.

6. Wetland, Isolated. See “Non-federally regulated wetland.”

7. “Wetland mitigation bank” means a site or suite of sites where resources are restored, created, enhanced, and/or preserved, for the purpose of providing compensatory mitigation for impacts. In general, a mitigation bank sells compensatory mitigation credits to permittees whose obligation to provide compensatory mitigation is then transferred to the mitigation bank sponsor. The operation and use of a mitigation bank are governed by a mitigation banking instrument.

8. “Wetland mosaic” means an area with a concentration of multiple small wetlands, in which each patch of wetland is less than one acre; patches are less than 100 feet from each other; and areas delineated as wetland are more than 50 percent of the total area of the entire mosaic, including uplands and open water.

X. “X” Definitions. Reserved.

Y. “Y” Definitions. Reserved.

Z. “Z” Definitions. Reserved. (Ord. O-24-831 § 1 (Exh. C); Ord. O-12-492 § 6; Ord. O-06-333 § 1).

18.60.040 Appeals.

Any decision to approve, condition or deny a development proposal based on the requirements of this chapter may be appealed according to and as part of the appeal procedure for the permit or approval involved. (Ord. O-06-333 § 1).

18.60.050 Critical area rules.

The Director of Community Development is authorized to adopt such administrative rules and regulations as are necessary and appropriate to implement the provisions of this chapter. (Ord. O-06-333 § 1).

18.60.060 Complete exemptions.

The following are exempt from the provisions of this chapter and any other applicable administrative rules. All exempted activities shall use reasonable methods to avoid potential impacts to critical areas. Exemption does not give permission to degrade a critical area or ignore risk from natural hazards. Any part of a critical area or buffer that is subject to an exempted alteration shall be promptly restored, rehabilitated or replaced by the party responsible for performing the alterations, and result in no net loss of critical area functions and values.

A. Alterations in response to emergencies which threaten the public health, safety and welfare or which pose an imminent risk of damage to private property as long as any alteration undertaken pursuant to this subsection is reported to the Department immediately. The Director shall confirm that an emergency exists and determine what, if any, mitigation shall be required to protect the health, safety, welfare and environment and to repair any resource damage.

B. Public water, electric and natural gas distribution, public sanitary sewer, cable communications, telephone utility and related activities undertaken pursuant to approved best management practices, as follows:

1. Normal and routine maintenance or repair of existing utility structures or rights-of-way;

2. Relocation of electric facilities, lines, equipment or appurtenances, not including substations, with an associated voltage of 55,000 volts or less, only when required by a local governmental agency which approves the new location of the facilities;

3. Replacement, operation, repair, modification or installation or construction in existing, developed utility corridors, an improved right-of-way or authorized private roadway of all electric facilities, lines, equipment or appurtenances, not including substations;

4. Relocation of public sewer local collection, public water local distribution, electric, natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or appurtenances, only when required by a local governmental agency which approves the new location of the facilities;

5. Replacement, operation, repair, modification, installation or construction of public sewer and water, electric, natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or appurtenances when such facilities are located within an improved public right-of-way or City-authorized private roadway;

C. Maintenance, operation, repair, modification or replacement of publicly improved roadways as long as any such alteration does not involve the expansion of roadways or related improvements into previously unimproved rights-of-way or portions of rights-of-way;

D. Maintenance, operation or repair of publicly improved recreation areas as long as any such alteration does not involve the expansion of improvements into previously unimproved recreation areas;

E. Public agency development proposals only to the extent of any construction contract awarded prior to adoption of critical areas regulations on November 27, 1990; provided, that any law or regulation in effect at the time of such award shall apply to the proposal;

F. Invasive and/or noxious plant removal using hand tools and Ecology-approved aquatic herbicides and adjuvants. Avoid the use of hazardous substances and soil compaction.

G. Habitat enhancement actions that do not involve clearing, grading, in-water work or construction activities, such as revegetation with native plants. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.070 Partial exemptions.

The following developments, activities, and associated uses shall be exempt from the review process of this chapter and any administrative rules promulgated thereunder provided such activities are otherwise consistent with the purpose of this chapter and other applicable regulations. The Director may apply conditions to an underlying permit or approval to ensure that the uses are consistent with the provisions of this chapter. Other State and federal permits and approvals may still apply.

A. Structural modification of, addition to or replacement of structures, except single detached residences, in existence prior to adoption of critical areas regulations on November 27, 1990, which do not meet the building setback or buffer requirements for wetlands, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the structure lying within the above-described building setback area, critical area or buffer;

B. Structural modification of, addition to or replacement of single-family detached residences in existence prior to adoption of critical areas regulations on November 27, 1990, which do not meet the building setback or buffer requirements for wetlands, streams or steep slope hazard areas if the modification, addition, replacement or related activity does not increase the existing footprint of the residence lying within the above-described buffer or building setback area by more than 1,000 square feet over that existed prior to adoption of critical areas regulations on November 27, 1990, and no portion of the modification, addition or replacement is located closer to the critical area or, if the existing residence is in the critical area, extends farther into the critical area; and

C. Maintenance or repair of structures which do not meet the development standards of this chapter for coal mine, landslide or seismic hazard areas if the maintenance or repair does not increase the footprint of the structure and there is no increased risk to life or property as a result of the proposed maintenance or repair.

D. A permit or approval sought as part of a development proposal for which multiple permits are required if:

1. The City previously reviewed all critical areas on the site;

2. There is no material change in the development proposal since the prior review;

3. There is no new information available which is important to any critical area review of the site or particular critical area;

4. The permit or approval under which the prior review was conducted has not expired or, if no expiration date, no more than five years lapsed since the issuance of that permit or approval; and

5. The prior permit or approval, including any conditions, has been complied with. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.080 Exceptions.

A. Public Agency/Utility Exception. If the application of this chapter would prohibit a development proposal by a public agency or utility, the agency or utility may apply for an exception pursuant to this subsection:

1. The public agency or utility shall apply to the Department and shall make available to the Department other related project documents such as permit applications to other agencies, special studies and SEPA documents.

2. The Department shall review the application based on the following criteria and may approve the application only if:

a. There is no other practical alternative to the proposed development with less impact on the critical area;

b. The proposal minimizes the impact on critical areas; and

c. The proposal results in no net loss to wetlands or fish and wildlife habitat conservation areas.

3. The department shall process exceptions, provide public notice, and provide opportunity for the public to request a public hearing, and provide an appeal process consistent with the provisions of Process 2.

4. This exception shall not allow the use of the following critical areas for regional retention/detention facilities except where there is a clear showing that the facility will protect public health and safety or repair damaged natural resources:

a. Type S or Type F streams or buffers;

b. Category I wetlands or buffers with plant associations of infrequent occurrence; or

c. Category I or II wetlands or buffers which provide critical or outstanding habitat for herons, raptors or State or federal designated endangered or threatened species unless clearly demonstrated by the applicant that there will be no impact on such habitat.

Other State and federal permits and approvals may still apply.

B. Reasonable Use Exception. If the application of this chapter would deny all reasonable use of the property, the applicant may apply for an exception pursuant to this subsection:

1. The applicant may apply for a reasonable use exception pursuant to Process 2 without first having applied for a variance. The applicant shall apply to the department, and the department shall make a final decision based on the following criteria:

a. The application of this chapter would deny all reasonable use of the property;

b. There is no other reasonable use with less impact on the critical area;

c. The proposed development does not pose an unreasonable threat to the public health, safety or welfare on or off the development proposal site and is consistent with the general purposes of this chapter and the public interest;

d. Any alterations permitted to the critical area shall be the minimum necessary to allow for reasonable use of the property; and any authorized alteration of a critical area under this subsection shall be subject to conditions established by the department including, but not limited to, mitigation and monitoring under an approved mitigation plan.

e. The inability of the applicant to derive reasonable use of the property is not the result of actions by the current or previous owner in subdividing the property or adjusting a boundary line, thereby creating the undevelopable condition, after the effective date of the ordinance codified in this chapter.

2. The Director of Community Development shall review the application in consultation with the City Attorney and the Public Works Department and shall approve the application only if the following criteria are met:

a. The application of this chapter would deny all reasonable use of the property;

b. There is no other reasonable use with less impact on the critical area;

d. Any alterations permitted to the critical area shall be the minimum necessary to allow for reasonable use of the property.

Other State and federal permits and approvals may still apply. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.090 Modification or waiver of critical area requirements for single-family residential.

The purpose of this section is to provide an alternative to the exception process and to minimize impacts to critical areas by allowing minor modifications which allow single-family residences on existing, legal lots without requiring a variance or exception. The Director shall have the discretion to modify or waive some or all of the requirements of this chapter in accordance with the provisions of this section.

A. The applicant for the modification or waiver of critical area requirements shall submit any critical area special studies following a preapplication review meeting as well as such other documents or studies, as requested by the Director.

B. The Director may grant a modification or waiver of critical area requirements for single-family residence applications provided:

1. The proposal is the minimum necessary to accommodate the building footprint and access. In no case, however, shall the area of alteration exceed 5,000 square feet, including access.

2. Access is located so as to have the least impact on the critical area and its buffer.

3. The proposal preserves the functions and values of wetlands and streams to the maximum extent possible.

4. Adverse impacts resulting from alterations of steep slopes are minimized.

5. The proposal includes on-site mitigation to the maximum extent possible.

6. The proposal will not significantly affect drainage capabilities, flood potential, erosion hazard areas, and steep slopes and landslide hazards on neighboring properties.

7. The proposal first develops noncritical area land, then the critical area buffer before the critical area itself is developed.

8. The proposal complies with State and federal regulations.

C. The Director shall require on-site or off-site mitigation measures to compensate for the loss of the functions and values of the critical areas and may impose mitigating conditions to the modification or waiver in order to meet the standards of this subsection.

D. Modifications pursuant to this chapter that relate only to the buffer or building setback requirements for Single-Family Residential Permits shall be reviewed and decided using Process 1 in conjunction with the Building Permit application. Modifications that would impinge upon the critical area itself shall be reviewed and decided using Process 2.

E. This section shall not apply to the following critical areas:

1. Steep slope hazard areas that are unmitigatable landslide hazard areas;

2. Steep slope hazard areas of slope greater than 70 percent where either the lot or slope are abutting and above a Category I or II wetland or Type S and Type F stream, and associated buffers, or an open stormwater conveyance system;

3. Type S and Type F streams and associated buffers; and

4. Category I and II wetlands and associated buffers

Other State and federal permits and approvals may still apply. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.100 Disclosure by applicant.

A. The applicant shall disclose to the City the presence of critical areas on the development proposal site and any mapped or identifiable critical areas within 100 feet of the applicant’s property to the extent known by, or readily available to, the applicant.

B. If the development proposal site contains or is within a critical area, the applicant shall submit a statement which declares whether the applicant has knowledge of any illegal alteration to any or all critical areas on the development proposal site and whether the applicant previously has been found in violation of this chapter. If the applicant previously has been found in violation, the applicant shall declare whether such violation has been corrected to the satisfaction of the City. (Ord. O-06-333 § 1).

18.60.110 Critical area review.

A. The City shall perform a critical area review for any development proposal permit application or other request for permission to proceed with an alteration on a site which includes a critical area or is within an identified critical area buffer or building setback area.

B. As part of the critical area review, the City shall:

1. Determine whether any critical area exists on the property and confirm its nature and type;

2. Determine whether a critical area special study is required;

3. Evaluate the critical area special study;

4. Determine whether the development proposal is consistent with this chapter;

5. Determine whether any proposed alteration to the critical area is necessary by utilizing mitigation sequencing as outlined in MVMC 18.60.140; and

6. 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 chapter. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.120 Critical area special study requirement.

A. When review is required, an applicant for a new development proposal which includes a critical area or is within an identified critical area buffer shall submit a critical area special study to adequately evaluate the proposal and all probable impacts.

B. The City may waive the full requirement for a special study if the applicant documents, to the City’s satisfaction, that any of the following are met:

1. There will be no alteration of the critical area or buffer;

2. The development proposal will not have an impact on the critical area in a manner contrary to the goals, purposes, objectives and requirements of this chapter; and

3. The minimum standards required by this chapter are met.

C. If necessary to ensure compliance with this chapter, the City may require additional information from the applicant, separate from the special study. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.130 Contents of critical area special study.

A. The critical area special study shall be in the form of a written report that has been prepared by a qualified professional and shall contain the following, as applicable:

1. Identification and characterization of all critical areas on or encompassing the development proposal site;

2. Assessment of the impacts or risks of any alteration proposed for a critical area or buffer, assessment of the impacts of any alteration on the development proposal, other properties and the environment, and/or assessment of the impacts to the development proposal resulting from development in the critical area or buffer;

3. Studies which propose adequate mitigation, maintenance, monitoring and contingency plans and bonding measures;

4. A scale map of the development proposal site; and

5. Detailed studies on habitat value, hydrology, geological hazard, erosion and sedimentation and/or water quality. Such detailed studies shall include specific recommendations for mitigation which may be required as a condition of any development proposal approval. The recommendations may include, but are not limited to, construction techniques or design, drainage or density specifications.

6. Mitigation, if required.

7. Other detailed studies, as required by the Director.

B. A critical area special study may be combined with any studies required by other laws and regulations; and

C. If the development proposal will affect only a part of the development proposal site, the City may limit the scope of the required special study to include only that part of the site which may be affected by the development. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.140 Mitigation sequencing.

A. As determined by the City, mitigation sequence measures shall be in place to protect critical areas and buffers from alterations occurring on the development proposal site, as defined in WAC 197-11-768. The following mitigation options are listed in 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 to critical areas by repairing, rehabilitating, or restoring the affected environment.

4. Reducing or eliminating the impact or hazard over time by preservation and maintenance operations during the life of the action.

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

6. Monitoring the hazard or other required mitigation and taking remedial action when necessary.

B. Where monitoring reveals a significant deviation from predicted impacts or a failure of mitigation or maintenance measures, the applicant shall be responsible for appropriate corrective action which, when approved, shall be subject to further monitoring.

C. If compensatory mitigation is required, to the maximum extent practical, mitigation should occur on or contiguous to the development site. The city may approve mitigation that is off the development site (including permittee responsible sites, mitigation banks or in-lieu fee programs) if an applicant demonstrates that:

1. It is not practical to mitigate on or contiguous to the development proposal site; and

2. The off-site mitigation will achieve equivalent or greater functions and values. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06333 § 1).

18.60.150 Financial guarantees.

Financial guarantees may be required by the Director in the form of bonds, letters of credit, assignment of savings accounts, or similar performance or maintenance security devices. (Ord. O-06-333 § 1).

18.60.160 Vegetation management plan.

A. For all development proposals where preservation or enhancement of existing vegetation is required by this chapter or by conditions of approval for a Process 2, 3, or 4 application, a vegetation management plan shall be submitted and approved prior to issuance of the permit or other request for permission to proceed with an alteration.

B. The vegetation management plan shall identify the proposed clearing limits for the project and any areas where vegetation in a critical area or its buffer is proposed to be disturbed.

C. Where clearing includes cutting any merchantable stand of timber, as defined in WAC 222-16-010(28), the vegetation management plan shall include a description of proposed logging practices which demonstrates how all critical areas will be protected in accordance with the provisions of this chapter.

D. Clearing limits as shown on the plan shall be marked in the field in a prominent and durable manner. Proposed methods of field marking shall be reviewed and approved by City prior to any site alteration. Field marking shall remain in place until the Certificate of Occupancy or final project approval is granted.

E. The vegetation management plan may be incorporated into a temporary erosion and sediment control plan or landscaping plan where either of these plans is required by other laws or regulations.

F. Submittal requirements for vegetation management plans shall be set forth in administrative rules. (Ord. O-06-333 § 1).

18.60.170 Critical area tract markers and signs.

A. Permanent survey stakes delineating the boundary between adjoining property and critical area tracts shall be set, using iron or concrete markers as established by current survey standards.

B. The boundary between a critical area tract and contiguous land shall be identified with permanent signs at intervals as required by the Director. (Ord. O-06-333 § 1).

18.60.180 Notice on title.

A. The owner of any property containing critical areas or buffers on which a development proposal is approved, except a public right-of-way or the site of a permanent public facility, shall file a notice approved by the City with the King County Records and Elections Division. The required contents and form of the notice shall be set forth in administrative rules. The notice shall inform the public of the presence of critical areas or buffers on the property, of the application of this chapter to the property and that limitations on actions in or affecting such critical areas or buffers may exist. The notice shall run with the land.

B. The applicant shall submit proof that the notice has been filed for public record before the City shall issue permits for any development proposal for the property or, in the case of subdivisions, short subdivisions and binding site plans, at or before recording the final plat or final binding site plan. (Ord. O-06-333 § 1).

18.60.190 Critical area tracts and designations on site plans.

A. Critical area tracts shall be used to delineate and protect those critical areas and buffers listed below in development proposals for subdivisions, short subdivisions or binding site plans, and shall be recorded on all documents of title of record for all affected lots:

1. All landslide hazard areas and buffers which are one acre or greater in size;

2. All erosion or steep slope hazard areas and buffers which are one acre or greater in size;

3. All wetlands and buffers; and

4. All streams and buffers.

B. Any required critical area tract shall be held in an undivided interest by each owner of a building lot within the development with this ownership interest passing with the ownership of the lot or shall be held by an incorporated homeowners’ association or other legal entity which assures the ownership, maintenance and protection of the tract.

C. Site plans submitted as part of development proposals for Building Permits, master plan developments and Clearing and Grading Permits shall include and delineate all landslide, and steep slope hazard areas, streams and wetlands, buffers and building setbacks. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.200 Alteration.

Any human activity which results or is likely to result in an impact upon the existing condition, function or value, of a critical area is an alteration which is subject to specific limitations as specified for each critical area. Alterations include, but are not limited to, grading, filling, dredging, draining, channelizing, applying herbicides or pesticides or any hazardous substance, discharging pollutants except stormwater, grazing domestic animals, paving, constructing, applying gravel, modifying for surface water management purposes, cutting, pruning, topping, trimming, relocating or removing vegetation or any other human activity which results or is likely to result in an impact to ecological functions or values such as existing vegetation, hydrology, fish or wildlife habitat. Alterations do not include walking, fishing or any other passive recreation or other similar activities. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.210 Building setbacks.

Unless otherwise provided, buildings and other structures shall be set back a distance of 15 feet from the edges of all critical area buffers or from the edges of all critical areas, if no buffers are required. The following may be allowed in the building setback area:

A. Landscaping;

B. Uncovered decks;

C. Building overhangs if such overhangs do not extend more than 18 inches into the setback area; and

D. Impervious ground surfaces, such as driveways and patios; provided, that such improvements may be subject to special drainage provisions. (Ord. O-06-333 § 1).

18.60.220 Erosion hazard areas.

Erosion hazard areas (a type of geologically hazardous area) include areas likely to become unstable, such as bluffs, steep slopes, and areas with unconsolidated soils. The following development regulations are required for any area identified as “erosion hazard”:

A. Clearing on an erosion hazard area is allowed only from April 1st to September 1st, except that:

1. Up to 15,000 square feet may be cleared on any lot, subject to any other requirement for vegetation retention and subject to any Clearing and Grading Permit required by the MVMC; and

2. Timber harvest may be allowed pursuant to an approved Forest Practice Permit issued by the Washington Department of Natural Resources.

B. All development proposals on sites containing erosion hazard areas shall include a temporary erosion control plan consistent with this section and other laws and regulations prior to receiving approval. Specific requirements for such plans shall be set forth by the Director.

C. All subdivisions, short subdivisions or binding site plans on sites with erosion hazard areas shall comply with the following additional requirements:

1. Except as provided in this section, existing vegetation shall be retained on all lots until Building Permits are approved for development on individual lots;

2. If any vegetation on the lots is damaged or removed during construction of the subdivision infrastructure, the applicant shall be required to submit a restoration plan to the City for review and approval. Following approval, the applicant shall be required to implement the plan;

3. Clearing of vegetation on lots may be allowed without a separate Clearing and Grading Permit if the City determines that:

a. Such clearing is a necessary part of a large scale grading plan;

b. It is not feasible to perform such grading on an individual lot basis; and

c. Drainage from the graded area will meet water quality standards to be established by administrative rules.

D. Where the City determines that erosion from a development site poses a significant risk of damage to downstream receiving waters, based either on the size of the project, the proximity to the receiving water or the sensitivity of the receiving water, the applicant shall be required to provide regular monitoring of surface water discharge from the site. If the project does not meet water quality standards established by law or administrative rules, the City may suspend further development work on the site until such standards are met.

E. The use of hazardous substances, pesticides and fertilizers in erosion hazard areas shall be prohibited unless specifically approved on a case-by-case basis by the City. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.230 Landslide hazard areas.

The following development regulations are required for any area identified as landslide hazard (a type of geologically hazardous area). A development proposal on a site containing a landslide hazard area shall meet the following requirements:

A. A minimum buffer of 50 feet shall be established from all edges of the landslide hazard area. The buffer shall be extended as required to mitigate a steep slope or erosion hazard or as otherwise necessary to protect the public health, safety and welfare;

B. Unless otherwise provided herein or as part of an approved alteration, removal of any vegetation from a landslide hazard area or buffer shall be prohibited, except for limited removal of vegetation necessary for surveying purposes and for the removal of hazard trees determined to be unsafe according to tree selection rules promulgated pursuant to this chapter. Notice to the City shall be provided prior to any vegetation removal permitted by this subsection;

C. Vegetation on slopes within a landslide hazard area or buffer which has been damaged by human activity or infested by noxious weeds may be replaced with vegetation native to the City pursuant to an enhancement plan approved by the City. The use of hazardous substances, pesticides and fertilizers in landslide hazard areas and their buffers may be prohibited by the City; and

D. Alterations to landslide hazard areas and buffers may be allowed only as follows:

1. A landslide hazard area located on a slope 40 percent or steeper may be altered only if the alteration meets the standards and limitations set forth for steep slope hazard areas in MVMC 18.60.250;

2. A landslide hazard area located on a slope less than 40 percent may be altered only if the alteration meets the following requirements:

a. The development proposal will not decrease slope stability on contiguous properties; and

b. Mitigation based on the best available engineering and geological practices is implemented which either eliminates or minimizes the risk of damage, death or injury resulting from landslides; and

3. Neither buffers nor a critical area tract shall be required if the alteration meets the standards of this subsection (D). (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.240 Seismic hazard areas.

A development proposal on a site containing a seismic hazard area (a type of geologically hazardous area) shall meet the following requirements:

A. Unless exempt, development proposals shall be subject to review standards based on two occupancy types: critical facilities and other structures. The review standards for critical facilities shall be based on longer earthquake reoccurrence intervals. The review standards for both occupancy types shall be set forth in administrative rules;

B. Alterations to seismic hazard areas may be allowed only as follows:

1. The evaluation of site-specific subsurface conditions shows that the proposed development site is not located in a seismic hazard area; or

2. Mitigation based on the best available engineering and geological practices is implemented which either eliminates or minimizes the risk of damage, death or injury resulting from seismically induced settlement or soil liquefaction.

C. Buildings with less than 2,500 square feet of floor area or roof area (whichever is greater) that contain no living quarters and that are not used as places of employment or public assembly are exempt from the provisions of this section. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.250 Steep slope hazard areas.

A development proposal on a site containing a steep slope hazard area shall meet the following requirements:

A. A minimum buffer of 50 feet shall be established from the top, toe and along all sides of any slope 40 percent or steeper. The buffer shall be extended as required to mitigate a landslide or erosion hazard or as otherwise necessary to protect the public health, safety and welfare. The buffer may be reduced to a minimum of 10 feet if, based on a special study, the City determines that the reduction will adequately protect the proposed development and the critical area. For single-family residential Building Permits only, the City may waive the special study requirement if other development in the area has already provided sufficient information or if such information is otherwise readily available. The City may authorize buffer reductions to no less than 10 feet if the City determines that the reduction will adequately protect the proposed development and the critical area pursuant to the requirements for a special study under MVMC 18.60.130.

B. Unless otherwise provided herein or as part of an approved alteration, removal of any vegetation from a steep slope hazard area or buffer shall be prohibited, except for limited removal of vegetation necessary for surveying purposes and for the removal of hazard trees determined to be unsafe according to tree selection rules promulgated pursuant to this chapter. Notice to the City shall be provided prior to any vegetation removal permitted by this subsection.

C. Vegetation on steep slopes within steep slope hazard areas or their buffers which has been damaged by human activity or infested by noxious weeds may be replaced with vegetation native to the City pursuant to a vegetation management plan approved by the City. The use of hazardous substances, pesticides and fertilizers in steep slope hazard areas and their buffers may be prohibited by the City.

D. Alterations to steep slope hazard areas and buffers may be allowed only as follows:

1. Approved surface water conveyances, as specified in the King County Surface Water Design Manual or other reference source or manual in use by the City, may be allowed on steep slopes if they are installed in a manner to minimize disturbance to the slope and vegetation;

2. Public and private trails may be allowed on steep slopes as approved by the City. Under no circumstances shall trails be constructed of concrete, asphalt or other impervious surfaces which will contribute to surface water runoff, unless such construction is necessary for soil stabilization or soil erosion prevention or unless the trail system is specifically designed and intended to be accessible to handicapped persons. Additional requirements for trail construction may be set forth in administrative rules;

3. Utility corridors may be allowed on steep slopes if a special study shows that such alteration will not subject the area to the risk of landslide or erosion;

4. Limited trimming and pruning of vegetation may be allowed on steep slopes pursuant to an approved vegetation management plan for the creation and maintenance of views if the soils are not disturbed and the activity is subject to administrative rules;

5. Approved mining and quarrying activities may be allowed;

6. Stabilization of sites where erosion or landsliding threaten public or private structures, utilities, roads, driveways or trails, or where erosion and landsliding threatens any lake, stream, wetland or shoreline. Stabilization work shall be performed in a manner which causes the least possible disturbance to the slope and its vegetative cover;

7. Reconstruction, remodeling, or replacement of existing structures;

8. Reconstruction, remodeling, or replacement of an existing structure upon another portion of an existing impervious surface which was established pursuant to City laws and regulations may be allowed, provided:

a. If within the buffer, the structure is located no closer to the steep slope than the existing structure;

b. The existing impervious surface within the buffer or steep slope is not expanded as a result of the reconstruction or replacement.

E. The following are exempt from the provisions of this section:

1. Slopes which are 40 percent or steeper with a vertical elevation change of up to 20 feet if no adverse impact will result from the exemption based on the City’s review of and concurrence with a soils report prepared by a geologist or geotechnical engineer; and

2. The approved regrading of any slope which was created through previous legal grading activities. Any slope which remains 40 percent or steeper following site development shall be subject to all requirements for steep slopes. (Ord. O-06-333 § 1).

18.60.255 Critical aquifer recharge areas.

The purposes of this section are to protect the functions and values of critical aquifer recharge areas and protect the quality and quantity of groundwater used for public water supplies.

A. Critical Aquifer Recharge Areas.

1. Critical aquifer recharge areas are categorized as follows:

a. Category I critical aquifer recharge areas include those mapped areas that King County has determined are:

i. Highly susceptible to groundwater contamination and that are located within a sole source aquifer or a wellhead protection area; or

ii. In an area where hydrogeologic mapping or a numerical flow transport model in a Washington Department of Health-approved wellhead protection plan demonstrate that the area is within the one year time of travel to a wellhead for a Group A water system;

b. Category II critical aquifer recharge areas include those mapped areas that King County has determined:

i. Have a medium susceptibility to ground water contamination and are located in a sole source aquifer or a wellhead protection area; or

ii. Are highly susceptible to groundwater contamination and are not located in a sole source aquifer or wellhead protection area; and

2. Development on or adjacent to a critical aquifer recharge area shall meet the following requirements:

a. For projects where the construction of structures and improvements, including additions, results in more than 50 percent total site impervious surface area, the applicant shall provide surface water infiltration according to a surface water management plan that mitigates impacts to the aquifer recharge process, or shall submit a hydrogeologic assessment, that indicates the proposal will not impact the recharge effect of the aquifer. Surface water management plans and hydrogeologic assessments shall be subject to review and approval by the Director.

b. For development that includes hazardous substance processing or handling, or significant diversion, alteration or reduction to the flow of surface or ground waters, or otherwise significantly reduces the recharging of the aquifer, the development must be designed and constructed in accordance with a critical areas study that includes a hydrogeologic assessment of ground water vulnerability, including an assessment of predicted impacts to groundwater recharge and ground water quality. Applications for development that will significantly affect groundwater recharge or quality shall be denied, if such impacts cannot be adequately mitigated.

c. The proposed activity must comply with the water source protection requirements and recommendations of the federal Environmental Protection Agency, State Department of Health, and Seattle-King County Public Health.

B. Storage Tanks. The Fire Marshal specifically regulates and authorizes permits for underground storage tanks, and the Washington Department of Ecology also regulates and authorizes permits for underground storage tanks. All storage tanks proposed to be located in a critical aquifer recharge area must comply with local building code requirements and must conform to the following requirements:

1. Underground Tanks. All new underground storage facilities proposed for use in the storage of hazardous substances or hazardous wastes shall be designed and constructed so as to:

a. Prevent releases due to corrosion or structural failure for the operational life of the tank;

b. Be protected against corrosion, constructed of noncorrosive material, steel clad with a noncorrosive material, or designed to include a secondary containment system to prevent the release or threatened release of any stored substances; and

c. Use material in the construction or lining of the tank that is compatible with the substance to be stored.

2. Aboveground Tanks. All new aboveground storage facilities proposed for use in the storage of hazardous substances or hazardous wastes shall be designed and constructed so as to:

a. Not allow the release of a hazardous substance to the ground, ground waters, or surface waters;

b. Have a primary containment area enclosing or underlying the tank or part thereof; and

c. For all tanks, a secondary containment system either built into the tank structure or a dike system built outside the tank.

C. Vehicle Repair and Servicing.

1. Vehicle repair and servicing must be conducted over impermeable pads and within a covered structure capable of withstanding normally expected weather conditions. Chemicals used in the process of vehicle repair and servicing must be stored in a manner that protects them from weather and provides containment should leaks occur.

2. No dry wells shall be allowed in critical aquifer recharge areas on sites used for vehicle repair and servicing. Dry wells existing on the site prior to facility establishment must be abandoned using techniques approved by the State Department of Ecology prior to commencement of the proposed activity.

D. Uses Prohibited From Critical Aquifer Recharge Areas. The following activities and uses are prohibited in critical aquifer recharge areas, provided expansion of existing uses may be allowed by the city if the applicant demonstrates through a special study that the proposed expansion will not negatively impact groundwater quality or recharge:

1. Waste transfer stations, landfills, and disposal of hazardous or dangerous waste, municipal solid waste, special waste, woodwaste, and inert and demolition waste;

2. Junk yards or metal recycling facilities with outdoor storage and handling facilities.

3. Inoperative vehicles. Storage of wrecked or inoperative vehicles, except as an accessory to an allowed use when stored over impervious paving with drainage controls designed to prevent ground water contamination.

4. Underground injection wells.

a. Class I wells

b. Class III wells

c. Class IV wells

d. Class V well subclasses 5F01 (Agricultural Drainage Wells), 5D03 (Improved Sinkholes), 5F04 5W09 (Untreated Sewage Waste Wells), 5W10 (Cesspools), 5W11 (Septic Systems – Undifferentiated Disposal Method), 5W31 (Septic Systems – Well Disposal Method), 5X13 (Mining, Sand, or Other Backwells), 5X14 (Solution Mining Wells), 5X15 (In situ Fossil Fuel Recovery Wells), 5W20, 5X28 (Motor Vehicle Waste Disposal Wells), and 5N24 (Radioactive Waste Disposal Wells);

5. Mining.

a. Metals and hard rock mining.

b. Sand and gravel mining.

6. Wood Treatment Facilities. Wood treatment facilities that allow any portion of the treatment process to occur over permeable surfaces (both natural and manmade);

7. Storage, processing, or disposal of radioactive substances. Facilities that store, process, or dispose of radioactive substances; and

8. Hazardous waste treatment, storage, and disposal facilities except those defined under permit by rule for industrial wastewater treatment processes per WAC 173-303-802(5)(c);

9. Chemical manufacturing, including but not limited to organic and inorganic chemicals, plastics and resins, pharmaceuticals, cleaning compounds, paints and lacquers, and agricultural chemicals;

10. Other.

a. Activities that would significantly reduce the recharge to aquifers currently or potentially used as a potable water source;

b. Activities that would significantly reduce the recharge to aquifers that are a source of significant baseflow to a regulated stream;

c. Activities that are not connected to an available sanitary sewer system are prohibited from critical aquifer recharge areas associated with sole source aquifers, this includes residential developments on septic systems, as well as other commercial or industrial uses that may drain to underground reservoirs.

E. State and Federal Regulations. The uses listed in Table X below shall be conditioned as necessary to protect critical aquifer recharge areas in accordance with the applicable State and federal regulations.

Table X

Statutes, Regulations, and Guidance Pertaining to Ground Water Impacting Activities
Activity	Statute – Regulation – Guidance
Above Ground Storage Tanks	WAC 173-303-640
Automobile Washers	Chapter 173-216 WAC, Best Management Practices for Vehicle and Equipment Discharges (WDOE WQ-R-95-56)
Below Ground Storage Tanks	Chapter 173-360 WAC
Chemical Treatment Storage and Disposal Facilities	Chapter 173-303-182 WAC
Hazardous Waste Generator (Boat Repair Shops, Biological Research Facility, Dry Cleaners, Furniture Stripping, Motor Vehicle Service Garages, Photographic Processing, Printing and Publishing Shops, etc.)	Chapter 173-303 WAC
Injection Wells	Federal 40 CFR Parts 144 and 146, Chapter 173-218 WAC
Junk Yards and Salvage Yards	Chapter 173-304 WAC, Best Management Practices to Prevent Stormwater Pollution at Vehicles Recycler Facilities (WDOE 94-146)
Oil and Gas Drilling	Chapter 173-218 WAC, WAC 332-12-450
On-Site Sewage Systems (Large Scale)	Chapter 173-240 WAC
On-Site Sewage Systems (< 14,500 gal/day)	Chapter 246-272 WAC, Local Health Ordinances
Pesticide Storage and Use	Chapter 15.54 RCW, Chapter 17.21 RCW
Sawmills	Chapter 173-303 WAC, Chapter 173-304 WAC, Best Management Practices to Prevent Stormwater Pollution at Log Yards (WDOE 95-53)
Solid Waste Handling and Recycling Facilities	Chapter 173-304 WAC
Surface Mining	WAC 332-18-015
Waste Water Application to Land Surface	Chapter 173-216 WAC, Chapter 173-200 WAC, WDOE Land Application Guidelines, Best Management Practices for Irrigated Agriculture

(Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.260 Wetlands.

A development proposal on a site containing a wetland shall meet the following requirements.

A. Identification – Delineation. Identification of wetlands and delineation of their boundaries shall be done in accordance with the approved federal wetland delineation manual and applicable regional supplement. Wetland delineations are valid for five years; after such date the City shall determine whether a revision or additional assessment is necessary. Wetland delineations will be documented on a ground-verified map using either professional surveying methods or an equivalent professional method using GPS with sub-meter accuracy.

B. Rating. Wetlands shall be rated according to the Washington State Wetland Rating System for Western Washington: 2014 Update, Version 2.0 (Ecology Publication [23-06-009] or as revised). Wetland ratings are valid for five years. Wetland rating categories shall not change due to illegal modifications made to the wetland.

1. Category I Wetlands. Category I wetlands are those that:

a. Represent a unique or rare wetland type; or

b. Are more sensitive to disturbance than most wetlands; or

c. Are relatively undisturbed and contain ecological attributes that are impossible to replace within a human lifetime; or

d. Provide a high level of functions. In western Washington, these include estuarine wetlands greater than an acre in size, natural heritage wetlands, bogs, mature and old growth forested wetlands, wetlands in coastal lagoons, and wetlands that perform many functions very well.

2. Category II Wetlands. 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. In western Washington, Category II wetlands include estuarine wetlands smaller than an acre in size (or if disturbed, larger than an acre), interdunal wetlands greater than an acre in size, and wetland that perform functions well.

3. Category III Wetlands. Category III wetlands are:

a. Wetlands with a moderate level of functions; and

b. Interdunal wetlands between 0.1 and one acre in size.

4. Category IV Wetlands. Category IV wetlands have the lowest levels of functions and often are disturbed. These wetlands can be replaced and, in some cases, improved. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.270 Wetlands – Regulated activities.

Alterations to wetlands and buffers may be allowed pursuant to the exception and modification provisions of MVMC 18.60.080 and 18.60.090 or as follows:

A. Alterations may be permitted if the City determines, based upon its review of special studies completed by qualified professionals, that:

1. The wetland does not meet the definition of “wetland” found in MVMC 18.60.030 including, but not limited to, biologic and hydrologic functions; or

2. The proposed development will:

a. Protect, restore or enhance the wildlife habitat, natural drainage or other valuable functions of the wetland resulting in a net improvement to the functions of the wetland system;

b. Develop a plan for its design, implementation, maintenance and monitoring prepared by a qualified biologist;

c. Perform the restoration or enhancement under the direction of a qualified biologist (per MVMC 18.60.030);

d. Will otherwise be consistent with the purposes of this chapter; and

e. Comply with federal and State regulations.

B. To establish whether the conditions in subsection (A) of this section are met, a critical area special study will be required (per MVMC 18.60.120). Such detailed studies shall include specific recommendations for mitigation which may be required as a condition of any development proposal approval. The recommendations may include, but are not limited to, construction techniques or design, drainage or density specifications;

The following activities are regulated if they occur in a wetland or its buffer:

1. The removal, excavation, grading, or dredging of soil, sand, gravel, minerals, organic matter, or material of any kind.

2. The dumping of, discharging of, or filling with any material.

3. The draining, flooding, or disturbing of the water level or water table.

4. Pile driving.

5. The placing of obstructions.

6. The construction, reconstruction, demolition, or expansion of any structure unless specifically exempted under MVMC 19.60.060 or 19.60.070.

7. The destruction or alteration of wetland vegetation through clearing, harvesting, shading, intentional burning, or planting of vegetation that would alter the character of the wetland.

Activities adjacent to a regulated wetland or its buffer that result in a significant change in water temperature, a significant change of physical or chemical characteristics of the sources of water to the wetland, or a significant change in the timing, frequency, depth, or duration of water entering or within the wetland or the introduction of pollutants.

C. The activities listed below are allowed in wetlands. These activities do not require submission of a critical area special study, except where such activities have the potential to result in a loss of the functions, values or area of a wetland or wetland buffer. These activities include:

1. Those activities and uses conducted pursuant to the Washington State Forest Practices Act and its rules and regulations, WAC 222-12-030, except those developments requiring local approval for a Class IV General Forest Practice Permit (conversions), provided conditions of that permit are met.

2. Conservation or preservation of soil, water, vegetation, fish, shellfish, and/or other wildlife that does not entail changing the structure or functions of the existing wetland.

3. 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.

4. Drilling for utilities/utility corridors under a wetland, with entrance/exit portals located completely outside of the wetland buffer; provided, that the drilling does not alter the ground water connection to the wetland or percolation of surface water down through the soil column. Trenching is not allowed by this provision.

5. Enhancement of a wetland through the removal of nonnative, invasive plant species. Removal shall be restricted to hand removal unless permits from the appropriate regulatory agencies have been obtained for approved biological or chemical treatments or mechanical methods. Plants that are on the Washington State Noxious Weed Control Board list should be handled and disposed of according to a noxious weed control plan appropriate to that species. Revegetation with appropriate native species to achieve natural densities is allowed and encouraged in conjunction with removal of invasive plants.

6. Educational and scientific research activities that do not result in altering the structure or functions of the wetland.

7. Normal and routine maintenance and repair of any existing, legally established public or private facilities within an existing right-of-way; provided, that the maintenance or repair does not expand the footprint of the facility or right-of-way and has no adverse effect on the wetland or buffer.

8. Stormwater management facilities. A wetland or its buffer can be physically or hydrologically altered to meet the requirements of a low impact development (LID) or flow control BMP if all of the following criteria are met:

a. The wetland is classified as a Category IV or a Category III wetland with a habitat score of three to five points.

b. There will be no net loss of ecological functions and values of the wetland.

c. The wetland does not contain a breeding population of any native amphibian species.

d. The hydrologic functions of the wetland can be improved as outlined in questions 3, 4, and 5 of Chart 4 and questions 2, 3, and 4 of Chart 5 in Selecting Mitigation Sites Using a Watershed Approach (Ecology Publication [No. 09-06-032], or as revised); or the wetland is part of a restoration plan intended to achieve restoration goals identified in a shoreline master program or a local or regional watershed plan.

e. The wetland lies in the natural routing of the runoff, and the discharge follows the natural routing.

f. All regulations regarding stormwater and wetland management are followed, including but not limited to local and State wetland and stormwater codes, manuals and permits.

g. Modifications that alter the structure of a wetland or its soils will require permits. Existing functions and values that are lost will need to be compensated.

D. If the application of these regulations would prohibit public facilities such as utilities within a wetland and/or buffer due to a specific service provision or design constraint, the agency or utility may apply for an exception. Exceptions applications must address mitigation sequencing, and include information meeting the review criteria according to the following:

1. There is no other practical alternative to the proposed development with less impact on the critical areas;

2. The application of the critical area regulations would unreasonably restrict the ability to provide utility services to the public;

3. The proposal does not pose an unreasonable threat to the public health, safety, or welfare on or off the development proposal site;

4. The proposal attempts to protect and mitigate impacts to the critical area functions and values consistent with best available science; and

5. The proposal is consistent with other applicable regulations and standards.

E. Emergencies are those activities necessary to prevent an immediate threat to public health, safety, or welfare, or that pose an immediate risk of damage to private property and that require remedial or preventive action in a timeframe too short to allow for compliance with the requirements of the critical areas regulations. Emergency actions are required to use reasonable methods to address the emergency with the least possible impact to the critical area. The Director will require review of the action to determine whether it was beyond the scope of the exemption and may require permits after the fact, which may include restoration or compensatory mitigation.

F. Wetland Buffers.

1. Buffer Requirements. The buffer tables 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 Western Washington: 2014 Update, Version 2.0 (Ecology Publication [No. 23-06-009], or as revised).

The following minimum buffers shall be established from the wetland edge:

Table 1

Wetland Buffer Width Requirements, In Feet
Category of Wetland	Habitat Score 3-5 points	Habitat Score 6-7 points	Habitat Score 8-9 points
Category I or II	75	110	225
Category III	60	110	225
Category IV	40	40	40

a. Impact Minimization Measures. Developments in a buffer are required to address the disturbance through the use of applicable minimization measures. Regulatory staff should determine, in coordination with the applicant, which measures are applicable and practicable. The applicant may propose alternate minimization measures that provide equivalent functions or values.

i. Lights. Direct lights away from wetland and use lights only where necessary for safety.

ii. Noise. Place activity that generates noise away from the wetland.

iii. Toxic runoff. Route all new untreated runoff away from wetland, or covenants limiting use of pesticides within 150 feet of wetland, or implement an approved integrated pest management program.

iv. Stormwater runoff. Infiltrate or treat, detain and disperse into buffer runoff from impervious surfaces, or implement recognized low impact development techniques. Prevent channelized or sheet flow from lawns that directly enters the buffer.

v. Pets and human disturbances. Install privacy fencing or landscaping to delineate buffer edge and to discourage disturbance of wildlife by humans and pets; place signs around the wetland buffer; when platting new subdivisions, locate greenbelts, stormwater facilities, and other lower-intensity uses adjacent to wetland buffers.

vi. Dust. Use of best management practices (BMPs) for control of dust.

vii. Degraded buffer condition. Nonnative plants to be removed and replaced with native vegetation per an approved landscaping plan. Habitat features such as bird boxes and large woody debris (LWD) placed into buffer areas in manner to improve habitat functions.

2. Buffer width averaging may be allowed by the City if it will provide additional protection to wetlands or enhance their functions and 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 area special study from a qualified wetland professional;

c. The total area of the buffer after averaging is equal to the area required without averaging; and

d. The buffer at its narrowest point is never less than 75 percent of the required width.

3. Averaging to allow reasonable use of a parcel may be permitted when all of the following are met:

a. No feasible alternatives to the site design 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 area special study from a qualified wetland professional;

c. The total buffer area after averaging is equal to the area required without averaging; and

d. The buffer at its narrowest point is never less than either 75 percent of the required width.

4. Increased buffer widths and enhancements to buffer vegetation shall be required by the City when necessary to protect wetlands. Provisions for additional buffer widths may be contained in administrative rules promulgated pursuant to this chapter including, but not limited to, provisions pertaining to critical drainage areas, location of hazardous substances, critical fish and wildlife habitat, landslide or erosion hazard areas contiguous to wetlands, groundwater recharge and discharge and the location of trail or utility corridors;

G. 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:

1. Conservation or restoration activities aimed at protecting the soil, water, vegetation, or wildlife.

2. Passive recreation facilities designed in accordance with an approved critical area special study, including:

a. Walkways and trails; provided, that they 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 (as defined in this chapter), old growth, or mature trees. They should be limited to pervious surfaces no more than five feet in width and designed for pedestrian use only. Raised boardwalks utilizing nontreated pilings may be acceptable.

b. Wildlife-viewing structures.

3. Educational and scientific research activities.

4. 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.

5. 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.

6. 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 alter 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 would be disturbed.

7. Enhancement of a wetland buffer through the removal of nonnative, 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 should 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.

8. Repair and maintenance of legally established nonconforming uses or structures, provided they do not increase the degree of nonconformity.

H. Functionally Disconnected Buffer Area. Buffers may exclude areas that are functionally and effectively disconnected from the wetland by an existing public or private road or legally established development, as determined by the Director. “Functionally and effectively disconnected” means that the road or other significant development blocks the protective measures provided by a buffer. Significant developments shall include built public infrastructure such as roads and railroads, and private developments such as homes or commercial structures. The Director shall evaluate whether the interruption will affect the entirety of the buffer. Individual structures may not fully interrupt buffer function. In such cases, the allowable buffer exclusion should be limited in scope to just the portion of the buffer that is affected. Where questions exist regarding whether a development functionally disconnects the buffer, or the extent of that impact, the Director may require a critical area special study to analyze and document the buffer functionality. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.280 Wetlands – Mitigation requirements.

A. The overall goal of compensatory mitigation shall be no net loss of overall wetland acreage or function, and to replace any wetland area lost with wetland(s) and buffers of equivalent functions and values. Before impacting any wetland or its buffer, an applicant shall demonstrate mitigation sequencing has been followed, pursuant to MVMC 18.60.140. Mitigation for lost or diminished wetland and buffer functions shall follow the compensatory actions listed in order of preference below:

1. Restoration (Reestablishment and Rehabilitation).

2. Establishment (Creation):

a. If a site is not available for wetland restoration to compensate for expected wetland and/or buffer impacts, the Director may authorize establishment of a wetland buffer upon demonstration by the applicant’s qualified wetland professional that:

i. The hydrology and soil conditions at the proposed mitigation site are conducive for sustaining the proposed wetland that establishment of a wetland at the site will not likely cause hydrologic problems elsewhere;

ii. Adjacent land uses and site conditions do not jeopardize the viability of the proposed wetland and buffer (e.g., due to the presence of invasive plants or noxious weeds, stormwater runoff, noise, light, or other impacts); and

iii. The proposed wetland and buffer will eventually be self-sustaining with little or no long-term maintenance;

iv. The proposed wetland would not be established at the cost of another high-functioning habitat (i.e., ecologically important uplands).

3. Preservation (Protection/Maintenance). Preservation of a wetland and associated buffer can be used only if:

a. The Director determines that the proposed preservation is the best mitigation option;

b. The proposed preservation site is under threat of undesirable ecological change due to permitted, planned, or likely actions that will not be adequately mitigated under existing regulations;

c. The area proposed for preservation is of high quality or critical for the health and ecological sustainability of the watershed or sub-basin.

d. Permanent preservation of the wetland and buffer shall be provided through a legal mechanism such as a conservation easement or tract held by an appropriate natural land resource manager/land trust.

e. The Director may approve another legal and administrative mechanism in lieu of a conservation easement if it is determined to be adequate to protect the site.

4. Enhancement may be allowed when a wetland or buffer will be altered pursuant to a development proposal, but the wetland’s biologic and hydrologic functions will be improved. Minimum requirements for enhancement shall be established in administrative rules.

B. All alterations of wetlands shall be replaced or enhanced on the site or within the same drainage basin using the following ratios:

Wetland Category	Reestablishment or Creation	Rehabilitation	Enhancement or Preservation
Category I	4:1	8:1	16:1
Category II	3:1	6:1	12:1
Category III	2:1	4:1	8:1
Category IV	1.5:1	3:1	6:1

Replacement or enhancement shall result in equivalent or greater biologic functions including, but not limited to, habitat functions and with equivalent hydrologic functions including, but not limited to, storage capacity.

C. On-site mitigation is the preferred option. Permittee-responsible compensatory mitigation actions shall be conducted using a watershed approach and shall generally occur within the same sub-drainage basin. Replacement or enhancement off-site may be allowed if the applicant demonstrates to the satisfaction of the City that the off-site location is in the same drainage sub-basin as the original wetland and that greater biologic and hydrologic functions will be achieved. The formulas in subsection (E) of this section shall apply to replacement and enhancement off the site.

D. The following criteria will be evaluated when determining whether on-site or off-site compensatory mitigation is ecologically preferable. When considering the location of mitigation, preference should be given to using approaches, such as a mitigation bank or an in-lieu fee (ILF) program.

1. No reasonable opportunities exist on site or within the sub-drainage basin or opportunities on site or within the sub-drainage basin do not have a high likelihood of success based on a determination of the capability of the site to compensate for the impacts;

2. On-site mitigation would require elimination of high-quality upland habitat;

3. Off-site mitigation has a greater likelihood of providing equal or improved wetland functions compared to the altered wetland;

4. Off-site locations shall be in the same sub-drainage basin unless:

a. Watershed goals for water quality, flood storage or conveyance, habitat, or other wetland functions have been established by the City and strongly justify locating mitigation at another site;

b. Credits from a State-certified wetland mitigation bank are used as compensation, and the use of credits is consistent with the terms of the certified bank instrument;

c. Fees are paid to an approved ILF program to compensate for the impacts.

5. The design for the compensatory mitigation project needs to be appropriate for its position in the landscape. Therefore, compensatory mitigation should not result in the creation, restoration, or enhancement of an atypical wetland.

E. Surface water management or flood control alterations including, but not limited to, wetponds shall not constitute replacement or enhancement unless other functions are simultaneously improved.

F. Mitigation sites should be located to alleviate wildlife habitat fragmentation.

G. Restoration shall be required when a wetland or its buffer is altered in violation of law or without any specific permission or approval by the City. The following minimum requirements shall be met for the restoration of a wetland:

1. The original wetland configuration shall be replicated including its depth, width, length and gradient at the original location;

2. The original soil type and configuration shall be replicated;

3. The wetland edge and buffer configuration shall be restored to its original condition;

4. The wetland edge and buffer shall be replanted with vegetation native to the City which replicates the original vegetation in species, sizes and densities; and

5. The original wetland functions shall be restored including, but not limited to, hydrologic and biologic functions. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.290 Wetlands – Mitigation bank and in-lieu fee.

The City may consider and approve replacement or enhancement of unavoidable adverse impacts to wetlands caused by the development activities through an approved wetland mitigation bank. Compensatory mitigation in advance of authorized impacts must be provided through an approved mitigation bank. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.300 Isolated wetlands – Limited exemption.

Isolated wetlands less than 1,000 square feet may be exempted from the provisions of MVMC 18.60.270 and 18.60.280 and may be altered by filling or dredging if the City determines that the cumulative impacts do not unduly counteract the purposes of this chapter and are mitigated pursuant to an approved mitigation plan. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.310 Streams.

Streams are a type of fish and wildlife habitat conservation area (FWHCA), and regulations outlined in MVMC 18.60.326 will also apply. Where a conflict exists the regulation that provides greater protection will be used. There shall be no net loss of stream functions or values as a result of a development. A development proposal on a site containing a stream or stream buffer shall meet the following requirements:

A. The following minimum buffers shall be established from the ordinary high water mark or from the top of the bank if the ordinary high water mark cannot be identified:

1. Type F streams shall have a 100-foot buffer;

2. Type Np streams shall have a 100-foot buffer;

3. Type Ns streams shall have a 100-foot buffer;

4. Any stream restored, relocated, replaced or enhanced because of a stream alteration shall have the minimum buffer required for the stream type involved;

5. Any stream with an ordinary high water mark within 25 feet of the toe of a slope 30 percent or steeper, but less than 40 percent, shall have:

a. The minimum buffer required for the stream type involved or a 25-foot buffer beyond the top of the slope, whichever is greater, if the horizontal length of the slope including small benches and terraces is within the buffer for that stream type; or

b. A 25-foot buffer beyond the minimum buffer required for the stream type involved if the horizontal length of the slope including small benches and terraces extends beyond the buffer for that stream type; and

6. Any stream adjoined by a riparian wetland or other contiguous critical area shall have the buffer required for the stream type involved or the buffer which applies to the wetland or other critical area, whichever is greater;

B. Buffer width averaging may be allowed by the City if it will provide additional protection to the stream or enhance their functions and when all of the following conditions are met:

1. The stream has significant differences in characteristics that affect its habitat functions, such as a stream with a forested buffer adjacent to a degraded buffer;

2. The buffer is increased adjacent to the higher-functioning area of habitat or more sensitive portion of the stream and decreased adjacent to the lower functioning or less sensitive portion as demonstrated by a critical area special study from a qualified professional;

3. The total area of the buffer after averaging is equal to the area required without averaging; and

4. The buffer at its narrowest point is never less than 75 percent of the required width.

C. Averaging to allow reasonable use of a parcel may be permitted when all of the following are met:

1. No feasible alternatives to the site design could be accomplished without buffer averaging;

2. The averaged buffer will not result in degradation of the stream’s functions and values as demonstrated by a critical area special study from a qualified professional;

3. The total buffer area after averaging is equal to the area required without averaging; and

4. The buffer at its narrowest point is never less than either 75 percent of the required width.

D. Increased buffer widths shall be required by the City when necessary to protect streams. Provisions for additional buffer widths shall be contained in administrative rules promulgated pursuant to this chapter including, but not limited to, critical drainage areas, location of hazardous substances, critical fish and wildlife habitat, landslide or erosion hazard areas contiguous to streams, groundwater recharge and discharge and the location of trail or utility corridors.

E. The use of hazardous substances, pesticides and fertilizers in the stream corridor and its buffer is prohibited.

F. Alterations to streams and buffers may be allowed pursuant to MVMC 18.60.080 and 18.60.090 or as follows:

1. Alterations may only be permitted if based upon a special study.

2. The applicant shall notify affected communities and native tribes of proposed alterations prior to any alteration if a stream is in a flood hazard area and shall submit evidence of such notification to the Federal Insurance Administration.

3. There shall be no introduction of any invasive plants or wildlife.

G. The following surface water management activities and facilities may be allowed in stream buffers as follows:

1. Surface water discharge to a stream from a detention facility, presettlement pond or other surface water management activity or facility may be allowed if the discharge is in compliance with State and federal regulations, the King County Surface Water Design Manual or such other manual as is in use by the City;

2. A Type F stream or buffer may be used for a regional retention/detention facility if:

a. A public agency and utility exception is granted pursuant to MVMC 18.60.080;

b. All requirements of the King County Surface Water Design Manual or such other manual as is in use by the City are met;

c. All requirements of applicable State and federal regulations are met;

d. The use will not alter the rating or the factors used in rating the stream; and

e. There are no significant adverse impacts to the stream.

3. A Type F stream or buffer may be used as a regional retention/detention facility if the alteration will have no lasting adverse impact on any stream and all requirements of the King County Surface Water Design Manual, or such other manual as is in use by the City are met and all requirements of applicable State and federal regulations are met.

H. Except as provided in subsection (I) of this section, public and private trails may be allowed in stream buffers only upon adoption of administrative rules consistent with the following:

1. The trail surface shall not be made of impervious materials; and

2. Buffers shall be expanded, where possible, equal to the width of the trail corridor including disturbed areas.

I. Stream crossings may be allowed and may encroach on the otherwise required stream buffer if:

1. All crossings use bridges or other construction techniques which do not disturb the stream bed or bank, except that bottomless culverts or other appropriate methods to provide fish passage may be used if the applicant demonstrates that such methods and their implementation will pose no harm to the stream or inhibit migration of fish;

2. All crossings are constructed during the summer low flow and are timed to avoid stream disturbance during periods when use is critical to salmonids;

3. Crossings do not occur over salmonid spawning areas unless the City determines that no other possible crossing site exists;

4. Bridge piers or abutments are not placed within the FEMA floodway or the ordinary high water mark;

5. Crossings do not diminish the flood-carrying capacity of the stream;

6. Underground utility crossings are laterally drilled and located at a depth of four feet below the maximum depth of scour for the base flood predicted by a civil engineer licensed by the State of Washington. Temporary bore pits to perform such crossings may be permitted within the stream buffer established in subsection (A) of this section. Crossing of Type F streams when dry may be made with open cuts;

7. Crossings are minimized and serve multiple purposes and properties whenever possible; and

8. Crossings comply with applicable State and federal regulations.

J. Stream relocations may be allowed only for:

1. Type S or F streams as part of a public road project for which a public agency and utility exception is granted pursuant to MVMC 18.60.080; and

2. Type F streams for the purpose of enhancing resources in the stream if:

a. Appropriate floodplain protection measures are used; and

b. The relocation occurs on the site, except that relocation off the site may be allowed if the applicant demonstrates that any on-site relocation is impracticable, the applicant provides all necessary easements and waivers from affected property owners and the off-site location is in the same drainage sub-basin as the original stream.

K. For any relocation allowed by this section, the applicant shall demonstrate, based on information provided by a civil engineer and a qualified biologist, that:

1. The equivalent base flood storage volume and function will be maintained;

2. There will be no adverse impact to local groundwater;

3. There will be no increase in velocity;

4. There will be no interbasin transfer of water;

5. There will be no increase in sediment load;

6. Requirements set out in the mitigation plan are met;

7. The relocation conforms to other applicable laws; and

8. All work will be carried out under the direct supervision of a qualified biologist.

L. A stream channel may be stabilized if:

1. Movement of the stream channel threatens existing residential or commercial structures, public facilities or improvements, unique natural resources or the only existing access to property; and

2. The stabilization is done in compliance with the requirements of any applicable rules or regulations related to flood hazard or flood plain areas.

M. Stream enhancement not associated with any other development proposal may be allowed if accomplished according to a plan for its design, implementation, maintenance and monitoring prepared by a civil engineer and a qualified biologist and carried out under the direction of a qualified biologist.

N. A minor stream restoration project for fish habitat enhancement may be allowed, with consideration for a streamlined review process, if:

1. The restoration is sponsored by a public agency with a mandate to do such work or approved by the Director;

2. The restoration is unassociated with mitigation of a specific development proposal;

3. The restoration is limited to placement of rock weirs, log controls, spawning gravel and other specific salmonid habitat improvements;

4. The restoration only involves the use of hand labor and light equipment; or the use of helicopters and cranes which deliver supplies to the project site; provided, that they have no contact with critical areas or their buffers; and

5. The restoration is performed under the direction of a qualified professional.

O. Roadside and agricultural drainage ditches which carry streams with salmonids may be maintained through the use of best management practices developed in consultation with relevant county, State and federal agencies.

P. Functionally Disconnected Buffer Area. Buffers may exclude areas that are functionally and effectively disconnected from the stream by an existing public or private road or legally established development, as determined by the Director. “Functionally and effectively disconnected” means that the road or other significant development blocks the protective measures provided by a buffer. Reconstruction, remodeling, or replacement of an existing structure upon another portion of an existing impervious surface which was established pursuant to City codes and regulations may be allowed provided:

1. If within the buffer, the structure is located no closer to the stream than the existing structure;

2. The existing impervious surface within the buffer or stream is not expanded as a result of the reconstruction or replacement; and

3. Individual structures do not fully interrupt buffer function. In such cases, the allowable buffer exclusion should be limited in scope to just the portion of the buffer that is affected. Where questions exist regarding whether a development functionally disconnects the buffer, or the extent of that impact, the Director may require a critical area special study to analyze and document the buffer functionality.

Q. To establish whether the conditions in subsections (A) through (O) of this section are met, a critical area special study will be required (per MVMC 18.60.120). Such detailed studies shall include specific recommendations for mitigation which may be required as a condition of any development proposal approval. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.320 Restoration and mitigation.

The overall goal of compensatory mitigation shall be no net loss of overall acreage or function, and to replace any area lost with stream(s) and buffers of equivalent functions and values. Before impacting any stream or its buffer, an applicant shall demonstrate mitigation sequencing has been followed, pursuant to MVMC 180.60.140.

A. Restoration shall be required when a stream or its buffer is altered in violation of law or without any specific permission or approval by the City. A mitigation plan for the restoration shall demonstrate that:

1. The stream has been degraded and will not be further degraded by the restoration activity;

2. The restoration will reliably and demonstrably improve the water quality and fish and wildlife habitat of the stream;

3. The restoration will have no lasting significant adverse impact on any stream functions; and

4. The restoration will assist in stabilizing the stream channel.

B. The following minimum requirements shall be met for the restoration of a stream:

1. All work shall be carried out under the direct supervision of a qualified biologist;

2. Basin analysis shall be performed to determine hydrologic conditions;

3. The natural channel dimensions shall be replicated including its depth, width, length and gradient at the original location, and the original horizontal alignment (meander lengths) shall be replaced;

4. The bottom shall be restored with identical or similar materials;

5. The bank and buffer configuration shall be restored to its original condition;

6. The channel, bank and buffer areas shall be replanted with vegetation native to the City which replicates the original vegetation in species, sizes and densities; and

7. The original biologic functions of the stream shall be recreated.

C. The requirements in subsection (B) of this section may be modified if the applicant demonstrates to the satisfaction of the City that a greater biologic function can otherwise be obtained.

D. Replacement or enhancement shall be required when a stream or buffer is altered pursuant to an approved development proposal. There shall be no net loss of stream functions on a development proposal site and no impact on stream functions above or below the site due to approved alterations. The requirements that apply to the restoration of streams in subsection (B) of this section shall also apply to the relocation of streams, unless the applicant demonstrates to the satisfaction of the City that a greater biologic function can be obtained by modifying these requirements.

E. Replacement or enhancement for approved stream alterations shall be accomplished in streams and on the site unless the applicant demonstrates to the satisfaction of the City that:

1. Enhancement or replacement on the site is not possible;

2. The off-site location is in the same drainage sub-basin as the original stream; and

3. Greater biologic and hydrologic functions will be achieved.

F. Surface water management or flood control alterations shall not be considered enhancement unless other functions are simultaneously improved. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1).

18.60.326 Fish and wildlife habitat conservation areas.

A development proposal on a site containing a fish and wildlife habitat conservation areas or its buffer shall meet the following requirements:

A. Due to the type of habitat or species present or the project area conditions, the Director will require an assessment of habitats including the following site- and proposal-related information at a minimum:

1. Identification of any non-aquatic priority species, or endangered, threatened, sensitive or candidate species that have a primary association with habitat on or adjacent to the project area, and assessment of potential project impacts to the use of the site by the species;

2. A discussion of any federal, State, or local special management recommendations, including Washington Department of Fish and Wildlife habitat management recommendations, that have been developed for species or habitats located on or adjacent to the project area;

3. A discussion of any ongoing management practices that will protect habitat after the project site has been developed, including any proposed monitoring, maintenance, and adaptive management programs.

4. If there is a potential impact, the Director may also require the habitat management plan to include an evaluation by the Washington Department of Fish and Wildlife or other qualified expert regarding the applicant’s analysis and the effectiveness of any proposed mitigating measures or programs, to include any recommendations as appropriate.

B. To protect fish and wildlife habitat conservation areas, the Director may require the establishment of buffers in or adjacent to these areas. Buffers shall consist of an undisturbed area of native vegetation, or areas identified for restoration, established to protect the integrity and functions of the habitat. Required buffer widths shall reflect the sensitivity of the habitat and the type and intensity of human activity proposed to be conducted nearby. When a species is more susceptible to adverse impacts during specific periods of the year, seasonal restrictions may apply. Activities may be further restricted and buffers may be increased during the specified season.

C. If a use, activity, or development is within, adjacent to, or likely to affect one or more specific fish and wildlife habitat conservation areas, the following provisions shall apply:

1. A fish and wildlife habitat conservation area and associated buffer may be altered only if the proposed alteration of the habitat and associated buffer does not degrade the functions of the habitat and associated buffer, and the applicant has demonstrated that mitigation sequencing has been followed.

2. Plant or wildlife species not indigenous to Western Washington shall be excluded from habitat conservation areas and associated buffers unless authorized by a State or federal permit or approval.

3. Mitigation sites should be located to achieve contiguous wildlife habitat corridors in accordance with a mitigation plan that is part of an approved critical area study to minimize the isolating effects of development on habitat areas.

4. The Director shall condition approvals of activities allowed within or adjacent to a habitat conservation area or its buffers, as necessary to minimize or mitigate any potential adverse impacts. Conditions may include, but are not limited to, the following:

a. Establishment of buffer zones;

b. Preservation of critically important vegetation;

c. Limitation of public access to the habitat area, including fencing to deter unauthorized access;

d. Seasonal restriction of activities;

e. Establishment of a duration and timetable for periodic review of mitigation activities; and

f. Requirement of a performance bond, when necessary, to ensure completion and success of proposed mitigation.

D. To establish whether the conditions in subsections (A) through (C) of this section are met, a critical area special study is required (per MVMC 18.60.120). Such detailed studies shall include specific recommendations for mitigation which may be required as a condition of any development proposal approval.

E. Endangered, Threatened, and Sensitive Species. No development shall be allowed within a fish and wildlife habitat conservation area or buffer with which State or federally endangered, threatened, or sensitive species have a primary association, except that which is provided for by a management plan established by the Washington Department of Fish and Wildlife or applicable State or federal agency.

Whenever activities are proposed adjacent to a fish and wildlife habitat conservation area with which State or federally endangered, threatened, or sensitive species have a primary association, such area shall be protected through the application of protection measures in accordance with a special study prepared by a qualified professional and approved by the Director. Approval for alteration of land adjacent to the fish and wildlife habitat conservation area or its buffer shall not occur prior to consultation with the Washington Department of Fish and Wildlife for animal species, the Washington State Department of Natural Resources for plant species, and other appropriate federal or State agencies.

Areas “with a primary association with listed species” should be considered per WAC 365-190-130(2)(a).

F. Anadromous Fish. All activities, uses, and alterations proposed to be located in water bodies used by anadromous fish or in areas that affect such water bodies shall give special consideration to the preservation and enhancement of anadromous fish habitat, including, but not limited to, adhering to the following standards:

1. Activities shall be timed to occur only during the allowable work window as designated by the Washington Department of Fish and Wildlife for the applicable species;

2. An alternative alignment or location for the activity is not feasible;

3. The activity is designed so that it will not degrade the functions or values of the fish habitat or other critical areas;

4. Shoreline erosion control measures shall be designed to use bioengineering methods or soft armoring techniques as the preferred method if feasible, according to an approved special environmental study; and

5. Any impacts to the functions or values of the fish and wildlife habitat conservation area are mitigated in accordance with an approved special environmental study.

a. Structures that prevent the migration of salmonids shall not be allowed in the portion of water bodies currently or historically used by anadromous fish. Fish bypass facilities shall be provided to prevent fish migrating downstream from being trapped or harmed.

b. Filling of aquatic habitats, when authorized by the City Shoreline Master Program, shall not adversely impact anadromous fish or habitat or shall mitigate any unavoidable impacts and shall only be allowed for a water-dependent use. (Ord. O-24-831 § 1 (Exh. C); Ord. O-06-333 § 1. Formerly 18.60.325).

18.60.330 Shorelines.

Reserved. (Ord. O-06-333 § 1).