HomeMy WebLinkAboutOrdinance No. 2025-023 Amending Chapter 20.90 of AMC Re Concurrency and Impace FeesORDINANCE NO. 2025-023
AN ORDINANCE OF THE CITY OF ARLINGTON, WASHINGTON AMENDING CHAPTER 20.90
OF THE ARLINGTON MUNICIPAL CODE REGARDING CONCURRENCY AND
IMPACT FEES UNDER CITY PLANNING NO. PLN 1040
WHEREAS, the city has proposed an update to the Concurrency and Impact Fees
regulations in the City zoning code; and
WHEREAS, the Planning Commission considered the same at workshops held on
November 4, 2025and public hearings conducted on November 18, 2025; and
WHEREAS, the Planning Commission made findings and provided its recommendations to
the City Council concerning the proposed changes; and
WHEREAS, the Parks, Arts, Recreation Commission reviewed the same revisions on
November 25, 2025 and recommended the proposed changes to City Council; and
WHEREAS, the City Council considered the same at a workshop held on December 8, 2025
and their regular meeting on December 15, 2025, and considered them along with the Planning
Commission recommendations; and the City Council having determined approving said
amendment was in the best interest of the City; and
WHEREAS, the amendments were presented to the Department of Commerce for
comment and said Department had no comments on the ordinance; and
WHEREAS, the City Council has considered the proposed amendment to the municipal
code and finds it to be consistent with city and state law and in the best interests of the citizens;
and
NOW, THEREFORE, the City Council of the City of Arlington does hereby ordain as follows:
Section 1. Arlington Municipal Code Chapter 20.90 Part III — 20.90.400 shall be and
hereby amended as follows:
Part III.011
;=-Community Parks Impact Fees.
20.90.400 Communit _;=' . r,,kP• a, ;_ L— Par Impact Fee,
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ORDINANCE NO. 2025-023 1
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ORDINANCE NO. 2025-023 2
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Section2. Severability. Should any section, paragraph, sentence, clause or phrase of this
ORDINANCE NO. 2025-023 3
ordinance, or its application to any person or circumstance, be declared unconstitutional or
otherwise invalid for any reason, or should any portion of this ordinance be pre-empted by state
or federal law or regulation, such decision or pre-emption shall not affect the validity of the
remaining portions of this ordinance or its application to other persons or circumstances.
Section 3. Effective Date. The title of this ordinance which summarizes the contents shall
be published in the official newspaper of the City. This ordinance shall take effect and be in full
force five (5) days after the date of publication as provided by law.
PASSED by the City Council of the City of Arlington and APPROVED by the Mayor this 15th
day of December, 2025.
CITY QF ARLINGTON
"r
Do E. Vanney, Mayor
ATTEST:
�A
Wendy Van D kersche, City Clerk
UJI C 971:11 WAL0]; I
Oskar Rey, City Attorney
ORDINANCE NO. 2025-023 4
1, Wendy Van Der Meersche, being the duly appointed City Clerk of the City of Arlington,
Washington, a municipal corporation, do hereby certify that the following Ordinance No.
2025-023 was approved at the December 15, 2025 City Council meeting.
5 1 4" 111,11 V.11 Ida M 01 113KIYARID
M mom Iff.1169] 4 Iff" KOUNUT 1110 to I V-11AA WK BIC
Wendy VadDer Meersche
City Clerk for the City of Arlington
20.93: Critical Area Ordinance
1mamuraromm I •nom-rM.T=
20.93.100 Purpose and Intent.
20.93.110 Definitions.
Part 11 - General Provisions
20.93.200 Applicability.
20.93.210 Identification, Classification, and Rating of Critical Areas.
20.93.220 Protection of Critical Areas.
20.93.230 Project Evaluation.
20.93.240 Critical Area Review.
20.93.250 Exempt Activities.
20.93.260 Permitted Alterations.
20.93.270 Reasonable Use Exception and Critical Area Variance.
20.93.280 Building Setbacks.
20.93.3 10 Critical Area Report.
20.93.320 Application Requirements.
9ft-9-1-1VI-Mitigation and Mitigation Plan Requirements.
20.93.340 Title Notification.
20.93.350 Field Marking.
20.93.360 Construction Plan Review, Monitoring, and Inspection.
20.93.370 Financial Guarantee Requirements.
20.93.380 Unauthorized Critical Area Alterations.
20.93.390 Final Decision and Appeals.
Part IV - Wetlands
20.93.400 Description and Purpose.
20.93.410 Identification, Designation, and Rating.
20.93.420 Mapping and Delineation.
20.93.430 General Development Standards.
20.93.440 Specific Wetland Category Development Standards.
20.93.450 Required Wetland Buffers.
20.93.460 Critical Area Report Additional Requirements.
20.93.470 Compensatory Mitigation Performance Standards and Requirements,
City of Arlington 20.93- 1 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
Part V - Fish and Wildlife Habitat Conservation Areas
20.93.500 Description and Purpose.
20.93.5 10 Designation.
20.93.520 Mapping.
20.93.530 General DeveloLcment Standards for Fish and Wildlife Habitat Conservation Areas.
20.93.540 Specific Standards for Type F, Type Np and Type Ns Waters.
20.93.550 Specific Riparian Management Zones Standards.
20.93.560 Specific Standards for other Fish and Wildlife Habitat Conservation Areas.
20.93.570 Stormwater Management Facilities.
20.93.580 Critical Area Report Additional Requirements.
20.93.590 Mitigation Performance Standards and Requirements.
Part VI - Geologically 1jazardous Areas
20.93.600 Description and Purpose.
20.93.610 Designation.
20.93.620 Mapping.
20.93.630 General Development Standards.
20.93.640 Specific Development Standards.
20,93,650 Critical Area Re�2ort Additional Reguirements.
Part V11 - Critical Aquifer Recharpe Areas
20.93.700 Description and Purpose.
20.93.710 Applicability and Hazardous Materials Questionnaire.
20.93.720 Designation.
20.93.730 Mapping.
20.93.740 General Development Standards.
20.93.750 Specific Development Standards for Regulated Facilities.
20.93.760 Critical Area Report Additional Requirements.
Part Vill - Frequentiv Flooded Areas
20.93.800 Description and Purpose.
20.93.810 Designation.
20.93.820 Mapping.
20.93.830 General Development Standards.
20.93.840 Critical Area Report Additional Requirements,
Part IX — Cultural Resources
20.93.900 Description and Purpose.
20.93.910 Preservation of Cultural Resources.
24.94.P21
20.93.930 Cultural Resource Management Plan.
20.93.940 Inadvertent Discovery.
City of Arlington 20.93-2 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
20-93. 1 00,---,lIqQ2()se and Intent
City of Arlington 20.93-3 Revised December 2025
For the purposes of this chapter, the following definitions shall apply:
"Agricultural Activities, Existing and Ongoing — Those activities conducted on lands defined in RCW
TAQNd those activities involved in the yroduction of crogs and livestock including but not limited
to operation, maintenance and conservation measures of farm and stock ponds or drainage ditches, irrigation
systems, changes between agricultural activities, and normal operation, maintenance or repair of existing
Legtructures ' facilities- or imyroved areas. Activities which brin- are not
part of an ongoing activity. An operation ceases to be ongoing when the area in which it was conducted is
proposed for conversion to nonagricultural use or has lain idle for a period of longer than five years unless the
idle land is registered in a federal or state soils conservation program.
"Alteration(s)". Any human -induced change in the existing condition of a critical area or its buffer.
Alterations include, but are not limited to, grading, filling, channelizing, dredging, clearing of vegetation,
construction, compaction, excavation, or any other activity that changes the character of the critical area.
"AMC". The Arlington Municipal Code.
"Applicant". A person who applies for any permit or approval to do anything governed by this code and
who is either the owner of the subject property, the authorized agent of the owner, or the city.
"Atypical Wetland". A wetland whose "design" does not match the type of wetland that would be found
Iri e the water source and h dro eriocl fro used for the miti
setting wastewater standards for industry. The EPA has also developed national water quality criteria
recommendations for pollutants in surface waters.
"Coastal Lagoon". See Wetlands with Special Characteristics.
City of Arlington 20.93-4 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"Commercial". Activity with goods, merchandise, or services for sale or rent.
"Compensatory Mitigation". The restoration (re-establishment or rehabilitation), establishment (creation),
enhancement, and/or in certain circumstances preservation of wetlands for the purposes of offsetting
unavoidable adverse impacts that remain after all appropriate and practicable avoidance and minimization has
been achieved.
"Constructed stormwater wetland". A stormwater management system that is designed and built to
function similar to the naturally occurring wetland including native trees and shrubs allowed to grow to
maturity.
"Cowardin Classification". A commonly used classification system for wetlands. It was first developed in
1979 by the U.S. Fish and Wildlife Service and updated in 2013 (Federal Geographic Data Committee, 2013).
Pmviwia? r iwww vegetation tW.&I and dominant
plant species. It is used for wetland classification in the National Wetland Inventory.
"Credit -Debit Method". A tool to provide applicants and regulators a way to determine whether actions
Washington State Wetland Rating System.
"Critical areas". Any of the following areas or ecosystems: (a) wetlands; (b) areas with a critical recharging
areas; and (e) geologically hazardous areas. "Fish and wildlife habitat conservation areas" does 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. (WAC 365-196-200(6) (a-e)).
"Critical Habitat". A term defined and used in the Endangered Species Act. It is 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.
"Creation". 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 function.
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.
"Cumulative Impacts or Effects". The combined, incremental effects of human activity on ecological or
critical area functions and values. Cumulative impacts result when the effects of an action are added to or
_:_ --- 14 with the effects of other actions in a yarticular ylace and within a particular time. It is the combination
of these effects, and any resulting environmental degradation, that should be the focus of cumulative impact
analysis and changes to policies and permitting decisions.
"Dedication". Deliberate appropriation of land by an owner for public use or purpose, reserving no other
rights than those that are compatible with the full exercise and enjoyment of the public use or purpose to which
the property has been devoted.
"Degraded wetland". A wetland in which the vegetation, soils, and/or hydrology have been adversely
altered, resulting in lost or reduced functions and values.
"Developable area". Land outside of critical areas and environmentally critical area setbacks and buffers.
"Development" A land use consisting of the construction or exterior alteration of structures; grading,
dredging, drilling, or dumping; filling; removal of sand, gravel, or minerals; bulk heading; driving of pilings;
which does not fall within the allowable exemptions contained in the City Code.
"Development permit". Any permit or approval under this code or the AMC that must be issued before
initiating a use or development activity.
"Ditch". A long narrow excavation dug in the earth for drainage with its top width less than ten feet at
design flow and that does not meet the definition of a stream. A ditch may be regulated if it conveys stream
flow.
"Easement". Land which has specific air, surface or subsurface rights conveyed for use by an entity other
than the owner of the subject property or to benefit some property other than the subject property.
City of Arlington 20.93-5 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"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 streamflow, aquifer water level,
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fish and wildlife habitat functions.
"Ecosystem Values" are the cultural, social, economic, and ecological benefits attributed to ecosystem
functions.
"Edge". The boundary of a wetland as delineated based on the criteria contained in this chapter.
"Emergencies". 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.
"Emergent wetland". See Wetlands with Special Characteristics.
"Enhancement". The manipulation of the physical, chemical, or biological characteristics of a wetland to
heighten, intensify, or improve specific function(s), but may also lead to a decline in other function(s).
Enhancement does not result in a gain in wetland area.
"Erosion hazard area". A landform or soil type subject to being worn away by the action of water, wind,
freeze -thaw, or ice.
"Establishment". See Creation.
"Exotic species". Plants or animals that are not native to the Puget Sound Lowlands region.
"Extraordinary hardship". Prevention of all reasonable economic use of the parcel due to strict application
of this chapter and/or programs adopted to implement this chapter.
"Fish Habitat" means habitat which is used by any fish at any life stage at any time of the year, including
potential habitat likely to be used by fish which could be recovered by restoration or management and includes
off -channel habitat.
"Fish and wildlife habitats (of local importance)". A seasonal range or habitat element with which a given
i ecies will maintain
and reproduce over the long-term. These might include areas of relative density
or species richness, breeding habitat, seasonal range, and movement corridors. These also include habitats of
limited availability or high vulnerability to alteration, such as cliffs and wetlands.
"Forested wetland". See Wetlands with Special Characteristics.
"Forest land". Land used for growing trees, not including Christmas trees, for commercial purposes (as
shown by record of any income) that has long-terin (six years or more) commercial significance.
"Functions and Values". The ecosystem services provided by critical areas to society, including, but not
limited to -improving, and maintainin- water fish and wildlife habitat,_Lu_oRorting terrestrial
TM..&1kn#,give flows- wave attenuation carbon seLf uestration therm.-h
refugia, historical or archaeological importance, cultural uses and significance, educational opportunities, and
recreation.
"Geologically hazardous areas". Includes areas susceptible to erosion, sliding, seismic activity, or other
geological events. They pose a threat to the health and safety of citizens when used as sites for incompatible
commercial, residential, or industrial development is sited in areas of significant hazard (WAC 365-190-120)
"Grading". The physical manipulation of the earth's surface and/or drainage pattern in preparation of an
intended use or activity.
"Growth Management Act". Chapters 36-70A and 36-70B RCW, as amended.
"Habitat Corridor". A legally protected, relatively undisturbed and vegetated area (e.g., Priority Habitats,
other compensation sites, wildlife areas/refuges, or national, county and state parks where they have
management plans with identified areas designated as Natural, Natural Forest, or Natural Area Preserve).
Including an area that is the site of a Watershed Project identified within and fully consistent with a Watershed
Plan (as these terms are defined by RCW 89-08-460), an area where development is prohibited per the
provisions of the local shoreline master program, or an area with equivalent habitat quality that has
conservation status in perpetuity, in consultation with WDFW.
City of Arlington 20.93-6 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"Hazard Tree" is defined as a threat to life, property, or public safety. Require that the method of hazard
+ -1
i.Al not adversely, affect rivarian ecosXstem functions to the extent yracticable encour tee the creation
of snags (priority habitat features) rather than complete tree removal, involve avoidance and minimization of
Ai2mrkl6r.g uVic
for hazard tree removal.
"Hazardous Substances". Any liquid, solid, gas, or sludge, including any material, substance, product,
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described in WAC 173-303-090 or 173-303-100.
"High quality native wetlands" will be classified by the state wetland rating system for Western
Washington. However, the following elements may be considered when identifying locally important functions
of a wetland:
(a) No, or isolated, human alteration of the wetland topography;
(b) No human -caused alteration of the hydrology or else the wetland appears to have recovered from the
alteration;
(c) Low cover and frequency of exotic plant species;
(d) Relatively little human -related disturbance of the native vegetation, or recovery from past disturbance;
(e) If the wetland system is degraded, it still contains a viable and high -quality example of a native
wetland community; and
(f) No known major water quality problems.
"Hydric soil". Soil that is saturated, flooded, or ponded long enough during the growing season to develop
anaerobic conditions in the upper part. The presence of hydric soil shall be determined following the methods
as defined by the National Technical Committee for Hydric Soils. The presence of hydric soil shall be
detennined following the methods described in the Regional Supplement to the Corps of Engineers Wetland
Delineation Manual: Western Mountains, Valleys, and Coast Region.
"Hydrophyte or hydrophytic vegetation". Plant life growing in water or on a substrate that is at least
periodically deficient in oxygen as a result of excessive water content. The presence of hydrophytic vegetation
shall be deten-nined following the methods described in the federal manual per RCW 90.58.380: Adoption of
Wetland Manual.
"Impervious Surface". 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 pre -development or pre -developed conditions. Common impervious surfaces include, but are not limited
to, roof tops, walkways, patios, driveways, parking lots, storage areas, concrete or asphalt paving, gravel roads,
i.cacked earthen materials. and oiled macadam or other surfaces which similarlgi im�oede the natural infiltration
of stormwater.
"In -Lieu Fee (ILF) Program". An agreement between a regulatory agency (state, federal, or local) and a
single sponsor, generally a public natural resource agency or non-profit organization. Under an in -lieu -fee
agreement, the sponsor collects funds from individuals and/or entities required to conduct compensatory
gation under a wetland regulatory program. The sponsor uses the funds pooled from multiple permittees
to create one or more mitigation sites under the authority of the agreement to satisfy the permittee's required
mitigations.
"Infiltration". The downward entry of water into the soil.
"Intermittent Streams" means those segments of streams that normally go dry.
"Improvement". Any structure or manmade feature.
"In -Kind Compensation". To replace critical areas with substitute areas whose characteristics and
functions closely approximate those destroyed or degraded by a regulated activity.
"Interdunal Wetland". See Wetlands with Special Characteristics.
"Landslide hazard areas". Areas potentially subject to risk of mass movement due to a combination of
factors, including historic failures.
City of Arlington 20.93-7 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"Low Impact Development (LID) Methodology". A stormwater and land -use management strategy that
site natural features, site planning, and distributed stormwater best management practices (BMPs) integrated
into project design.
"Mineral resource lands". Lands primarily devoted to the extraction of gravel, sand, other construction
materials, or valuable metallic or mineral substances.
"Mitigation Sequence". A prescribed order of steps taken to reduce the impacts of activities on wetlands.
As defined in WAC 197-11-768, mitigation means:
(a) Avoiding the impact altogether by not taking a certain action or parts of an action;
(b) Minimizing impacts by limiting the degree of magnitude of the action and its implementation by
using appropriate technology or by taking affirmative steps to avoid or reduce the impacts;
(c) Rectifying the impact to wetlands, critical aquifer recharge areas, and habitat conservation areas by
repairing, rehabilitating, or restoring the affected environment;
(d) Reducing or eliminating the impact or hazard over time by preservation and maintenance operations
during the life of the action;
(e) Compensating for the impact by replacing, enhancing, or providing substitute resources or
environments; and/or
(f) Monitoring the impact and taking remedial action when necessary.
"Monitoring". Evaluating the impacts of development proposals on the biological, hydrological, and
_rf-crinance of r e�v,uired mitigation measuresthrough
the collection and analysis of data by various methods for the purpose of understanding and documenting
changes in natural ecosystems and features. Monitoring includes gathering baseline data.
"National Wetland Inventory (NWI)". A publicly available resource provided by the U.S. Fish and
Wildlife Service that provides detailed information and maps showing the abundance, characteristics, and
distribution of wetlands in the U.S.
"Native vegetation". Plant species that occur naturally in a particular region or environment and were
present before European colonization.
"Natural condition". Lands that retain native vegetation, forest duff and naturally occurring contours and
drainage patterns not modified by human activity.
"Natural resource lands". Includes lands that are significant for long-term commercial purposes, such as
agriculture, forest, and mineral resource lands and follow the criteria of WAC 365-196-480.
"Nonconforming". Any use, structure, lot, condition, activity, or any other feature or element of private
property or the use or utilization of private property that does not conform to any of the provisions of this code
"Non -Federally Regulated Wetland". 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.
"Non -Natural Water Course" means constructed vegetated swales and ditches that are designed and
installed for the express purpose of periodically moving stormwater not associated with naturally occurring
streams.
"Off -Site Compensatory Mitigation". Replacement of critical areas away from the site on which a critical
area has been impacted.
"On -Site Compensatory Mitigation". Replacement of critical areas at or adjacent to the site on which a
critical area has been impacted.
"Open space". Land not covered by buildings, roadways, parking areas, or other surfaces through which
water cannot percolate into the underlying soils.
"Ordinary high-water mark". Under the Shoreline Management Act, that mark which is found by
examining the bed and banks of water bodies and ascertaining where the presence and action of waters are so
common and usual and so lowN continued in all ordinajyN�ears, that the soil has a character distinct from that
of the abutting upland in respect to vegetation.
Talustrine wetland". See Wetlands with Special Characteristics.
City of Arlington 20.93-8 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"Pond". Any inland body of water, either naturally or artificially formed or increased, that has a surface
area of one thousand square feet or more, except: These do not include ponds deliberately designed and created
from dry sites such as canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape
amenities.
"Practicable alternative". An alternative that is available and .r.• • being carried • after taking into
consideration cost, existing technology, and logistics in light of overall project purposes, and having less
be obtained, utilized, expanded, or managed in order to fulfill the basic purpose of the proposed activity.
"Preservation". The removal •I a threat to, or preventing the •- ♦ wetland conditions by an action
in • near a wetland. This term includes activities commonly associated with the protection and maintenance
•i • • the implementation • appropriate legal and • mechanisms (such as recording and
providing structural protection like fences and signs). Preservation does not result in a gain of wetland area
and • (but may result in a • • • • the long term).
"Priority Area". Known limiting habitats (e.g., breeding areas) or areas that support a relatively high
number of individuals (e.g., regular concentrations) identified in WDFW's Priority Habitats and Species List.
"Priority Habitats". As defined by WDFW, habitat types or elements with unique or significant value to a
nab ge of s ecie A riori habitat ma consist of a uni ue ve
City of Arlington 20.93-9 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(b) At least two additional years of full-time work experience as a wetland professional; including
delineating wetlands, preparing wetland reports, conducting function assessments, and developing
and implementing mitigation plans, and
(c) Completion of additional wetland -specific training programs. This could include a more
comprehensive program such as the University of Washington Wetland Science and Managemen)
Certificate Program or individual workshops on topics such as wetland delineation, function
assessment, gation design, hydrophytic plant or hydric soil identification.
A person certified as a Professional Wetland Scientist through the Society of Wetland Scientists professional
certification program meets the above criteria.
"Re-establishment". The manipulation of the physical, chemical, or biological characteristics of a site with
the goal of returning natural/historical functions and environmental processes to a former
wetland. Re-establishment results in rebuilding a former wetland and results in a gain in wetland area and
functions.
"Rehabilitation". 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 wetland.
Rehabilitation results in a gain in wetland function but does not result in a gain in wetland acres.
"Repair or Maintenance". 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 sco%e of a xro[ect bepond the ori , iprij, Irt& r otherwise alter
critical areas are not included in this definition.
"Restoration". Measures taken to restore an altered or damaged natural feature, including:
(a) Active steps taken to restore damaged wetlands, streams, protected habitat, or their buffers to the
functioning condition that existed prior to an unauthorized alteration; and
(b) Actions performed to re-establish structural and functional characteristics of a critical area that have
been lost by alteration, past management activities, or catastrophic events.
"Riparian habitat". An ecosystem that occurs in the transition zone between aquatic and upland
environments.
"Riparian Management Zone" (RMZ) means the area that has the potential to provide full riparian
611TOM&M it = irm Tarefir-la . - . lbh�&itate. this area occurs within one 200-pear site-(.i,,otential tree height
measured from the edge of the stream channel. In situations where a CMZ is present, this occurs within one
site potential tree height measured from the edges of the CMZ. In non -forested zones, the RMZ is defined by
the greater of the outermost point of the riparian vegetative community or the pollution removal function, at
100 feet.
"Revised Code of Washington (RCW)". A compilation of all permanent Washington state laws currently
in force.
"Scrub -shrub wetlands". See Wetlands with Special Characteristics.
"Seismic hazard areas". Areas subject to the risk of damage as a result of earthquake induced ground
shaking, slope failure, settlement, soil liquefaction or surface faulting. Ground shaking is a primary risk,
followed by some unstable slopes causing damage below them.
"SEPA". Washington State Environmental Policy Act, Chapter 43-21C RCW.
"Service Area". The geographic area within which impacts can be mitigated at a specific mitigation bank
or an in -lieu -fee program, as designated in its instrument.
"Shoreline Management Act (SMA)". Chapter 90-58 RCW, which is the law that requires all counties,
towns, and cities with shorelines to develop and implement shoreline master programs.
e-Potential Tree Height (SPTH200)" means the average maximum height of the tallest dominant trees
(200 years) and site class.
"Slope". See Section 20.93.600 (Geological Hazardous Areas - Classification).
"Soil Survey". The most recent Natural Resources Conservation Service soil maps for the local area or
county by the National Resources Conservation Service, U.S. Department of Agriculture.
"Species". Any group of animals or plants classified as a species or subspecies as commonly accepted by
the scientific community.
City of Arlington 20.93- 10 Revised December 2025
Title 20—Land Use •• Chapter 20.93: Critical Area Ordinance
"Species, Listed". Any species listed under the federal Endangered Species Act or state endangered,
• and sensitive, • priority lists (see WAC 220-610-110 • current "Priority Habitat and •
List," Washington Department of Fish and Wildlife)
"Sphagnum". Any of a large genus of mosses that grows only in wet acidic soils and whose remains
become compacted with • plant debris to form peat.
"Stream". An area where open surface water produces a defined channel or bed, not including irrigation
• canals, storm • surface water runoff devices, • other entirely artificial watercourses, unless they are
used by salmonids or are used to convey a watercourse that was
-�?Jqm, Am, 9 rsjoi_wx_tsxy_y.�*tr%ction. A channel or bed need not contain water ptaLzm "nqKi,,rovided there
is evidence • at least intermittent flow during years • • rainfall.
"Steep slope". See Section 20.93.600 (Geological Hazardous Areas —classification).
"Structure". Anything which is built or constructed; an edifice or building of any kind, or any piece of
• artificially built-up • composed • • joined together in some definite manner. Not included are fences
less than six feet in height, retaining wall, rockeries, and similar improvements of a minor character less than
three feet in height.
r• • The time lag between the loss • wetland • caused by the permitted •
unpermitted impacts and the replacement • wetland • at the compensatory mitigation site.
"Thermal Refugia". Sites within a landscape that are relatively protected from temperature extremes and
warming •
"Type F Water" • • natural waters other than Type S waters, which are within the bankfull widths
of defined channels and periodically inundated areas of their associated wetlands, or within lakes, ponds, or
impoundments having a surface area • 0.5 acre or greater at seasonal low water, as more fully described in
• 222-16-030.
"Type Np Water" means all segments • natural waters within the bankfull width • defined channels that
are • nonfish habitat streams. Perennial streams are flowing waters that •• • _• • any time • a
• ance sj,sEefils, • • 'ITIICFC LIIC CAI 7 T •
that has been • by humans.
"Water -dependent". A use for which the use • surface water would be essential in fulfilling the purpose
of the proposed project.
City of Arlington 20.93- 11 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
"Watershed Approach". A watershed approach means an analytical process for making compensatory
mitigation decisions that support the sustainability or improvement of wetlands in a watershed. It involves
consideration of watershed needs, and how locations and types of compensatory mitigation projects address
those needs. A landscape perspective is used to identify the types and locations of compensatory mitigation
City of Arlington 20.93- 12 Revised December 2025
20.93: Critical Area Ordinance
Part 11 — General Provisions
2!i. ) �32 0 0 �,Nl i ca �bi I i t y�
�aj Iniess expuciuy exempieu, ine pro I Frfflft—dU L•
all structures and facilities within the city of Arlington that are within the critical area, within the maximum
buffer distance of, likely to affect the functions and values of, one or more critical areas.
(b) Relationship to other regulations.
(1) Shorelines of the state and shorelands as defined in RCW 90.58.030, and critical areas occurring within
the jurisdiction of shorelines of the state and shorelands ("shoreline jurisdiction"), are regulated i
protected through the Arlington Shoreline Master Program, as amended. Activities occurring within
shoreline jurisdiction are reviewed through the shoreline permit review and issuance process.
Shoreline Master Program incorporates by reference portions of this chapter, however, certain
provisions of this chapter that are not consistent with the Shoreline Management Act, Chapter 90.85
RCW, and supporting Washington Administrative Code chapters do not apply in shoreline
jurisdiction.
(2) These critical areas regulations apply in addition to zoning and other regulations adopted by the city.
In the event of any conflict between these regulations and any other regulations of the city, the
regulations apply that provide greater protection to the critical areas' functions and values, as
determined by the Director.
(3) When any provision of this chapter or any existing easement, covenant, or deed restriction conflicts
with this chapter, the provision with the most protection to the critical areas applies.
(4) Compliance with the provisions of this chapter does not constitute compliance with other federal, state,
or local regulations and permit requirements that may be required. The applicant is responsible for
complying with other agency requirements, apart from the process established in this chapter.
1 of Critical Areas.
20.9' )—" 10 Identifica.tioii. ("lassification. and lUiiw
(a) Critical Area Maps.
(b) Actual Site Conditions. Regardless of whether a critical area is shown on the critical areas map, the actual
presence or absence of the features defined in this code as critical areas will govern. Prior to acting on any
development permit the city may require an applicant to submit technical information to indicate whether
critical areas actually exist on or adjacent to the applicant's site based on the definitions of critical areas
in this code. This will be administered as a critical area evaluation form (AMC 20.93.300) included with
appropriate permit forms.
(c) Classification and Rating. To promote consistent application of the standards and requirements of this
chapter, critical areas within the city will be rated or classified using best available science according to
their characteristics, function and value, and/or sensitivity to disturbance.
(1) Classification of critical areas will be determined by the city using the following tools:
(A) Application of the criteria contained in these regulations;
(B) Consideration of the critical area reports submitted by qualified professionals in connection with
applications subject to these regulations; and
(C) Review of maps and other resources adopted pursuant to this chapter.
(2) Rating categories will not change due to illegal modifications. If the development proposal site
contains or is within a critical area suspected of illegal modifications the rating will be based on
premodification conditions of the critical area. Abatement of the unauthorized modification will be
required prior to authorization of the current development proposal being processed for the subject
site.
City of Arlington 20.93- 13 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
20.93.220 Protection of Critical Areas.
(a) Critical areas and their required buffers may not be altered except as allowed by this chapter.
(b) Any action taken pursuant to this chapter must result in equivalent or greater functions and values of the
critical areas associated with the proposed action, as determined by the best available science.
(c) All actions and development must be designed and constructed in accordance with mitigation sequencing
per AMC 20.93.330 to achieve no net loss of critical area functions and values.
(d) Applicants must first demonstrate an actual inability to avoid or reduce impacts before restoration and
compensation of impacts will be allowed.
(e) No activity or use may be allowed that results in net loss of the functions or value of the critical areas.
(f) Any individual critical area adjoined by another type of critical area must have the buffer and meet the
requirements that provide the most protection to the critical area involved.
MILTA00"M *f1hi • d-R--�Ap-v.
Violations and Abatement. Where a violation occurs within a suspected protected critical area or as depicted
on city adopted mapping, the property owner must provide an appropriate critical area report to determine
impacts. The report may be subject to third party review at the property owner's expense.
20�)3�.130 ]�:Ir6ect �Fvalua�Cton
(a) As part of the review, the city will:
(1) Verify the information submitted by the applicant;
(2) Evaluate the project area and vicinity for critical areas;
(3) Determine whether the proposed project is likely to impact the functions or values of critical areas; and
(4) Determine if the proposed project adequately addresses the impacts and avoids impacts to the critical
area associated with the project.
(b) If the proposed project is within, adjacent to, or is likely to impact a critical area, the city will:
(1) Require a critical area report from the applicant that has been prepared by a qualified professional, to
be reviewed and evaluated;
(2) Determine whether the development proposal conforms to the purposes and performance standards of
this chapter, including the criteria in AMC 20.93.240, Critical Areas Review;
(3) Assess the potential impacts to the critical area and determine if they can be avoided or minimized; and
(4) Determine if any gation proposed by the applicant is sufficient to protect the functions and values
of the critical area and public health, safety, and welfare concerns consistent with the goals, purposes,
objectives, and requirements of this chapter.
(5) The city may require third party review of any critical area report at the expense of the applicant.
20.93.240 Critical Areas Review
(a) When Required. A proposal to modify any critical area and/or required buffer including, but not limited to,
clearing, grading, draining, removal or alteration of vegetation, construction of structures, utilities and
related infrastructure, must require a critical area evaluation unless it qualifies as an exemption, as provided
in AMC 20.93.250. Except that, for within shoreline jurisdiction, administration of this chapter shall be
through the Shoreline Master Program and appropriate shoreline permit administration process.
(b) Best Management Practices. All activities, including those allowed without critical areas review, must be
conducted using the best management practices appropriate for that activity that result in the least amount
of impact to the critical areas. Best management practices must be used for tree and vegetation protection,
construction management, erosion and sedimentation control, water quality protection, and regulation of
chemical applications. The use of best management practices is required to ensure that the activity does not
result in degradation to the critical area. Appropriate BMP sources include Ecology's Construction
Storrnwater General Permit and Natural Resources Conservation Service (NRCS) Practices. Any incidental
damage to, or alteration of, a critical area and/or buffer must be restored, rehabilitated, or replaced at the
responsible party's expense.
City of Arlington 20.93- 14 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(c) Modifications to Existing Nonconforming Structures and Uses. In these provisions the burden of proof is
on the applicant to bring evidence in support of their position. Existing structures, activities, and uses that
were established legally but do not meet the current critical area, buffer, or buffer setback requirements
may continue in accordance with AMC 20.32, Nonconforming Situations, and may be modified as follows:
(1) Routine maintenance and repairs;
(2) Structural modifications or additions that do not intensify the nonconformity of the structure or increase
the area of hardscape lying within the critical area or buffer. The Director may require an updated
critical area report to confirm location of buffers and that the addition is located entirely outside the
critical area or buffer;
(3) Vertical additions above the ground floor that do not encroach further into the critical area or buffer
beyond the existing exterior walls, except those critical areas review are required for additions in
landslide hazard areas or buffers;
(4) Restoration or replacement of a structure that is damaged by fire, natural disaster or other calamity
when:
(A) A complete application for reconstruction or replacement is submitted within one year of the
damage; and
(B) The restoration or replacement is made to conform to the current critical areas regulations, or if
such regulations cannot be physically met without reducing the size of the building, the restoration
or replacement may not intensify any nonconformity that existed prior to the damage;
(C) Except that critical area review is required for restoration and replacement in landslide hazards
areas or buffers;
(d) Demolition. Demolition of structures located within critical areas or their buffers is permitted, excluding
demolition of structures necessary to support or stabilize landslide hazard areas, and will be subject to
approval of a ston-nwater pollution prevention plan consistent with the adopted stormwater management
manual and clearing limits that will adequately protect the critical area.
20.93.250 Exeipgt Activities,
(a) General Requirements for All Exempt Activities. Activities listed in this section are exempt from the rn',
of the provisions of this chapter only if they meet the specific terrns of this section.
(b) To be exempt from this chapter does not give permission to degrade a critical area or buffer or to ignore
risk from natural hazards. All exempt activities must use reasonable methods to avoid potential impacts to
critical areas and buffers. In every case, disturbance to the critical area must be minimized through bes-i
management practices and the use of low -impact equipment.
(c) Any dental damage to, or alteration of, a critical area or buffer that is not a necessary outcome of the
exempted activity must be restored, rehabilitated, or replaced at the responsible party's expense.
(d) This chapter may not exempt an activity from the provisions of other city permits such as clearing and
grading for vegetation removal and ground disturbing activities, or agency permit requirements such as
Washington Department of Fish and Wildlife hydraulic permit, or Army Corps of Engineers regulatory
requirements.
(e) Burden of Proof. The burden of proof is on the applicant to bring forth evidence that the activity meets the
precise description of the exemption.
(f) Table 20.93.250-1 describes activities that must meet the precise description to be allowed withow
following a critical area process. Activities are divided into categories of permitted in the critical area an4
permitted in the buffer, marked by a yes or no in the appropriate column.
City of Arlington 20.93- 15 Revised December 2025
EXEMPT ACTIVITIES: No review reauired. must strictiv meet standard-,
tip I nm m,
chapter, if the following requirements are met:
(a) Only the minimum intervention necessary to reduce the risk to public health, safety, or welfare
and/or the imminent risk of damage to private property may be authorized by this exemption.
(b) The alteration undertaken must be reported to the Director no later than 30 days after the
alteration has occurred. Once notified, the Director must confirm that an emergency existed and
determine what, if any, additional applications and/or measures are required of the property owner
to protect the critical area(s) consistent with the provisions of this chapter, and to repair any damage
to a pre-existing resource.
(c) After the emergency, the person or agency undertaking the action must fully fund and conduct
necessary site evaluations and critical area reports, mitigation plans, and restoration for any
impacts to the critical area and buffers resulting from the emergency action. The person or agency
undertaking the action must meet the review procedures contained herein. Mitigation activities
must be initiated within one year of the date of the emergency or as directed by the Department.
(d) If the Director determines that the action taken, or any part of the action taken, was beyond the
scope of an allowed emergency action, or any required mitigation, the Director may take action to
enforce this chapter consistent with AMC Chapter 20.28, Enforcement and Review and AMC Title
11, Violations and Abatement.
1. 11 N11
crops, pruning and planting of noninvasive ornamental vegetation or indigenous native species t
maintain the general condition and extent of such areas; provided, that such maintenance or repai
activities are limited to legally existing landscaping improvements and do not further expand int
1 2 .2L."; r 2 1 d I t' le vegetation
•
liggig,
Site Investigation. Minimal site investigative work and studies necessary for preparing land use
applications, including, but not limited to, surveys, soil logs and borings, percolation tests, water tests and invest* -rovided—
t
Jig a
i-, jjjej r or hea e ui ment
M11 EW96re ME I I PJ I Wo I I tt KI I K1q I I I W-10W, I 97-rl 091,70111111 W i
L-701KI
100 W®r C L L 1-1
or vegetation, and that will not adversely affect the functions and values of critical areas.
C&Ical Area I Ma_ffer
WM
NO
Yes
City of Arlington 20.93- 16 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
EXEMPTIONS- That reauire a letter of exemption to be obtained from the Commulfty and
Economic Develooment Director nriot to construction or initiation of activities. Subiect to Critical Area Buffer
conditions is the Director to ensure egntoliance with thil chapter.
Utility Operation, Maintenance, Repair, or Replacement. Public water, electric, and natural gas
distribution, public stormwater and sewer collection, cable communications, telephone, utility and
related activities undertaken pursuant to city -approved best management practices, and best available
science with regard to protection of threatened and endangered species, as follows:
(a) Normal and routine maintenance or repair of existing utility structures or rights -of -way; when
the activity does not involve the expansion of facilities or improvements into a previously
unimproved portion of critical areas or required buffers;
(b) Replacement, operation, repair, modification, installation or construction in an improved city
road right-of-way or city -authorized private roadway of all electric facilities, lines, equipment
or appurtenances, not including substations, with an associated voltage of 55,000 volts or less;
to include relocation only when required by the city of Arlington, which approves the new
location of the facilities;
(c) Relocation of public sewer or stormwater local collection, public water local distribution, Yes
Yes l
natural gas, cable communication or telephone facilities, lines, pipes, mains, equipment or
appurtenances, only when required by the city of Arlington, which approves the new location
of the facilities;
(d) Replacement, operation, repair, modification, relocation, installation or construction of public
sewer or stormwater local collection, public water local distribution, 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;
(e) Repair and maintenance of existing private connections to public utilities and private
stormwater management facilities;
(f) Regular maintenance of stormwater facilities that are within a segment of a regulated stream,
L such as conveyance ditches/swales within the right-of-way or within public drainage
u s
eas
ements.
ts_
easements.
Transportation Infrastructure Operation, Maintenance, Repair, or Replacement.
Maintenance, operation, repair, modification, or replacement of publicly improved roadways or city -
authorized private roadways, including the road prism and associated stormwater management
systems; as long as any such alteration does not involve expansion of roadways or related
improvements into previously unimproved rights -of -way or portions of rights -of -way and does not y—eS Yes
alter a critical area or required buffer, or watercourse, such as culverts or bridges, or result in the
transport of sediment or increased stormwater. Retention and replanting of native vegetation must
occur whenever possible along the right-of-way improvement and resulting disturbance.
... . ......
Recreation Areas Operation, Maintenance, Repair, or Replacement.
Maintenance, operation, repair, modification, or replacement of existing trails, and existing facilities
within publicly improved recreation areas, and public parks, may be performed subject to the
following:
(a) The activity does not involve the expansion of facilities and disturbance to adjacent areas is
minimized and disturbed areas must be immediately restored; Yes Yes
(b) Work is conducted using best management practices;
(c) Flow and circulation patterns and biological characteristics are not impaired and adverse
impacts are minimized;
(d) Where trail relocation is the least impactful method of repair, trail relocation further away from
the critical area is not to be considered a new trail but is included in the exemption for operation
maintenance, repair, or replacement.
City of Arlington 20.93- 17 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
EXEMPTIaN:That re uire a letter otexemption.to be obtained fromtheCommunift and
Critical Area
Buffer
Economic Development Directorj2rior,to construction or initiation of activities. Subject to
conditions by the Director to ensure.comalk"ce With this chanter.
Vegetation Management, including:
(1) Removal of noxious weeds or invasive vegetation, as identified by the Washington State or
Snohomish County Noxious Weed Control Board, in a wetland buffer, stream buffer, other fish
and wildlife habitat conservation areas and buffers, is allowed when:
(a) Undertaken with hand labor, including handheld mechanical tools, and integrated pest
management;
(b) Plants that appear on the Washington State or Snohomish County Noxious Weed Control
Board lists must be handled and disposed of in accordance with the best management
practices appropriate to that species and approved by the city when permit review is
applicable;
(c) Areas cleared by removal of noxious and/or invasive plant species must be revegetated with
site -appropriate native species at natural densities and the site must be stabilized against
erosion in accordance with the stormwater manual adopted by the city;
(d) All work performed is above the ordinary high water mark and above the top of a stream
bank; and
(e) The following limits may not be exceeded: Within city -owned property, no more than 3,000
square feet of soil may be exposed at any one time; and within private property, not more
than 500 square feet of area may be cleared, as calculated cumulatively, over one year,
without a permit and critical area report prepared by a qualified professional.
(2) Vegetation management consistent with a previously approved critical area mitigation,
restoration, remediation, or enhancement plan that requires ongoing maintenance and vegetation
management beyond final inspection and the required monitoring period for the permitted
project.
(3) Hazard Trees.
(a) The falling of hazard trees may be permitted when necessary to:
Yes
Yes
(i) Control fire; or
(ii) Halt the spread of disease or damaging insects consistent with Chapter 76.09 RCW;
(iii) Avoid a threat to existing structures, above -ground utility lines or other facilities; or
(iv) Remove an actual threat to life or property from slope instability that would be caused
by toppling.
(b) Unless there is an emergency pursuant to emergency exemptions above, the landowner must
first obtain prior written approval from the Department. A tree risk assessment prepared by
an I SA certified arborist must be submitted by the applicant to the Department that includes
the following infon-nation:
(i) Identification of the tree(s) proposed to be removed;
(ii) The conclusion that the condition constitutes an actual threat to life or property;
(iii) An assessment of whether a portion of the tree suitable for a snag for wildlife habitat
may be safely retained;
(iv) If a tree to be removed provides priority habitat, such as an eagle perch or occupied
nest, a description of timing and methods of removal that will minimize and mitigate
impacts;
(v) If a tree to be removed is located within a landslide hazard area or buffer, an evaluation
of potential impacts on slope stability must be completed by a qualified professional,
including recommendations for replanting and other measures to avoid adverse impacts
to slope stability.
(c) All work must be done using handheld implements only, unless the property owner requests
and the Director approves otherwise in writing.
(d) Any removed tree or vegetation must be replaced in -kind, with similar or appropriate native
species, within one year in accordance with an approved restoration plan including species,
size, and maintenance plan.
Clearing, grading, and the construction of fences are allowed along the edge of a critical area
buffer to install Native Growth Protection Area fencing and is allowed within the building setback.
No
Yes
City of Arlington 20.93- 18 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinan=,;,
City of Arlington 20.93-19 Revised December 2025
Permitted Alterations: Zonina Permit Reouired Administrative Decision with Public Notice
Buffer Modifications, including increased buffer width, buffer averaging, and buffer alterations as
described specifically in this chapter.
Critical Area I ftffer
em
Ecology, Washington State Department of Fish and Wildlife, or other appropriate local, state, federal'�� Yes Yes
or tribal jurisdiction and/or that meet the criteria of RCW 77.55.181 (1) and that are reviewed and::i
approved according to the provisions of RCW 77.55.181. A biological • report is require(%
• determine whether the proposal would conserve, preserve, • enhance critical area • in thZ
• term to minimize temporary environmental impacts.
Chemical Application. The application of herbicides, pesticides, organic or mineral -derived fertilizers,
or other hazardous substances, if necessary for the control of nuisance weeds and algae; except that their
use will be restricted in accordance with the State Department of Ecology and State Department of Fish Yes Yes
and Wildlife Management recommendations, and regulations of the State Department of Agriculture
and the U.S. Environmental Protection Agency.
City of Arlington 20.93-20 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
Permitted Alterations: Zonina Permit Reauired Administrative DEcision,'with Public Notice I Critical Area I Luffer
Recreational Areas/Facilities. Low impact activities which are consistent with the purpose and
function of the critical area buffer and do not detract from its integrity may be permitted within the
buffer depending on the sensitivity of the critical area.
(a) Limited public park or public recreational access including trails, viewing platforms, fishing
access (no wider than six feet), and foot bridges; provided that all of the following are
satisfied:
(1) The area/facility is part of a public park that is dependent on its location for recreational
function; and
(2) The areas/facility are limited to the minimum necessary to accomplish the recreational
function; and
(3) The removal of trees and native vegetation is minimized; and
(4) The balance of the development is consistent with other requirements of this chapter; and
(5) The project is identified in the Arlington comprehensive plan or parks and recreation
master plan.
(b) Private pedestrian walkways and public trails must meet the following standards: No Yes
(1) The trail is generally parallel to the perimeter of the critical area;
(2) The trail is located in the outer 25 percent of the buffer area and is designed to avoid
removal of trees and native vegetation;
(3) The trail does not exceed six feet in width and is limited to native soils or pervious
surfaces. Raised boardwalks utilizing nontreated pilings may be acceptable; and
(4) The trail may be subject to closure during critical spawning, migration or breeding time
periods of sensitive species that are present.
(c) Informational Signs. Construction and placement of informational signs or educational
demonstration facilities no more than nine square feet surface area and four feet high, as long
as there is no permanent infringement on hydrology or stream flow and nontreated wood is
used;
(d) Limited excavation and filling necessary for the repair and maintenance of piers, walkways,
observation decks, wildlife management shelters, boathouses, and other similar water related
structures, provided they are built on pilings to allow unobstructed flow of water and preserve
the natural contour of the critical area.
legal lots may intrude into critical areas buffers when all of the following conditions are met:
(a) It is demonstrated that it is not feasible to avoid the buffer through avoidance or buffer
averaging, or reconfiguration of lots in the same ownership at the date of adoption of this
chapter, and the development is the minimum necessary to achieve reasonable use of the lot
as determined by the decision -maker; and
(b) Alteration of critical areas buffers including all clearing, grading, structures, and
appurtenances are outside all minimum buffer requirements for the specific critical area listed
in Part V — Wetlands, Part VI — Fish and Wildlife Habitat Conservation Areas, and VII —
Geologically Hazardous Areas; and
(c) This action does not allow critical areas buffers to be converted to lawn or residential
landscaping beyond a minimal area needed to maintain an approved structure; and
(d) Mitigation sequencing provided in this chapter under AMC 20.93.330 is applied and the
proposal includes on -site mitigation to the extent feasible as determined by the critical area
report.
(e) Normal appurtenances included in this provision including attached garages, decks, and
walkways dental to residential living and that do not constitute a special privilege.
Critical Area Aquifer Recharge Areas. All regulated activities listed under AMC 20.93.710,
Applicability and Hazard Materials Questionnaire.
City of Arlington 20.93-21 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
City of Arlington 20.93-22 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(7) The applicant has demonstrated that the criteria in AMC 20.20.030, Variance Criteria are met; and
(8) Granting the variance requested will not confer on the applicant any special privilege that is denied by
this chapter or other lands, structures, or building under similar circumstances; and
(9) The granting of the variance is consistent with the general purpose and intent of the Arlington
comprehensive plan, and planning policies.
•
militions. Conditions of aiACroval m"i be included as :iart of the decision including modifications to the
size and placement of structures and facilities to minimize impacts to critical areas and associated buffers
and mitigation requirements that ensure that all impacts are mitigated to the maximum extent feasible
utilizing best available science.
,J) Variances — Geologically Hazardous Areas. A variance must not authorize development within a
geologically hazardous area or required setback or buffer from a geologically hazardous area unless a
qualified professional has determined the development will not pose a threat to public safety or property.
20.93280 Building- letbacks.
(a) Unless otherwise provided, buildings and other structures must be set back 15 feet from the edges of all
critical area buffer boundaries. The following may be allowed in the building setback area:
(1) Landscaping;
(2) Uncovered decks;
(3) Building overhangs if such overhangs do not extend more than 18 inches into the setback area; and
(4) Impervious ground surfaces, such as driveways and patios; such improvements are subject to water
quality regulations as adopted in AMC Chapter 13.28.
Critical Area Buffer Building Exempt Area
Setback
(wetlands and
FHWCAs)
City of Arlington 20.93-23 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
Part III - Critical Areas Review Procedures
20.93.300 Critical Area Evaluation Form
applicant must submit to the Department a completed form identifying suspected critical areas on, and within
300 feet, of the site.
I Mus 1141111 RIMMKIMIK" all M11 WA so
City of Arlington 20.93-24 Revised December 2025
2(�93.320
(a) A complete application for a permitted alteration permit or reasonable use exception/variance permit must
•- the following information and materials • a form provided by the Director. For the r• • this
section, a complete application includes:
(1) The name and • information • the applicant;
(2) Adequate information to determine compliance with the requirements of the critical area regulations,
including a critical area report, impact and hazard assessment, and mitigation requirements specific to
each critical area type, as indicated in the corresponding sections of this chapter;
(3) Identification of the development permit(s) requested and all other local, state, and/or federal critical
area -related permits required for the project;
City of Arlington 20.93-25 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(4) Site plan, a scaled drawing of the development proposal including:
(A) Property and project site boundaries;
(B) An accurate depiction of all critical areas, including off -site critical areas and buffers that extend
onto the project site; a desk survey is acceptable when access to the adjacent property has been
denied;
(C) The development proposal including grading and clearing limits and areas of proposed impacts to
critical areas and/or buffers (including square footage estimates);
(D) A scaled depiction and description of the proposed stormwater pollution prevention plan consistent
with the adopted stormwater manual, for the development and consideration of impacts to critical
areas due to drainage alterations;
(E) An assessment of probable impacts to the critical areas resulting from the proposed development
of the site based upon identified findings;
(F) A description of reasonable efforts made to apply mitigation sequencing pursuant to AMC
20.93.330, Mitigation Requirements, to avoid, minimize, and mitigate impacts to critical areas; and
(G) Plans for mitigation required to offset any critical areas impacts, in accordance with AMC
20.93.3 3 0, Mitigation Plan Requirements, and the corresponding mitigation performance standards
sections of this chapter, including a discussion of the applicable development standards and cost
estimates for determination of financial guaranteed requirements.
(b) Additional Requirements. The Director may require additional information to be included in the critical
areas permit submittal when determined to be necessary to the review of the proposed activity in accordance
with this chapter. Additional information that may be required includes, but is not limited to:
(1) Historical data, including original and subsequent mapping, historical aerial photographs, data
compilations and summaries, and available reports and records relating to the site or past operations at
the site;
(2) Grading and stormwater management plans; and
(3) Information specific to the type, location, and nature of the critical area.
7093,330 Miligatioij-4nd-Mitioation Plan [ZCC t1irenient's.
(a) Mitigation must be sufficient to restore impacted functions and values, or compensate for the impacted
functions and values, of the critical area and to prevent risk from a hazard posed to a critical area by the
proposed activity. Mitigation must not be implemented until after the decision -maker has provided approval
of a critical area report that includes a mitigation plan.
(1) gation Sequencing. This section applies to mitigation required with all critical areas reviews,
approvals, and enforcement pursuant to this chapter. This section is supplemented with specific
measures under parts for particular critical area types. Mitigation for specific development proposals
may include a combination of the measures below and must be designed and constructed in accordance
with the provisions of this section. Before impacting any critical areas, an applicant must demonstrate
that the following actions have been taken in the following sequential order:
(A) Avoiding the impact altogether by not taking a certain action or parts of actions;
(B) Minimizing impacts by limiting the degree or magnitude of the action and its implementation by
using appropriate technology, or by taking affirmative steps, such as project redesign, relocation,
or timing, to avoid or reduce impacts;
(C) Rectifying the impact by repairing, rehabilitating, or restoring the affected environment or by
restoring or stabilizing the critical area through natural, engineering, or other methods;
(D) Reducing or eliminating the impacts or hazard over time by preservation and maintenance
operations during the life of the action;
(E) Compensating for the impact by replacing, enhancing, or providing substitute resources or
environments; and/or
(F) Monitoring, measuring and reporting the impact to the decision -maker and taking appropriate
corrective measures.
City of Arlington 20.93-26 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
City of Arlington 20.93-27 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
(5) Monitoring Reports.
(A) The as -built report, required prior to final inspection, must, at a minimum, include
documentation of the following:
(i) Departures from the original approved plans;
(ii) Construction supervision provided by the qualified professional;
(iii) Approved project goals and performance standards;
(iv) Baseline data for monitoring per the approved monitoring methods;
(v) Photos from established photo points; and
(vi) A site plan showing final mitigation as constructed or installed, monitoring points, and
photo points.
(B) Subsequent monitoring reports must, at a minimum, include:
(i) Monitoring visit observations, documentation, and analysis of monitoring data collected;
Photos from established photo points;
Determination whether performance standards are being met; and
(iv) Maintenance and/or contingency action recommendations to ensure success of the project
at the end of the monitoring period.
(C) The applicant is responsible for reimbursement of the cost of reviewing monitoring reports and site
inspections during the monitoring period which are completed by the city or a qualified
professional under contract with or employed by the city.
(6) Cost Estimates. The mitigation plan must include cost estimates that will be used by the city to calculate
the amounts of financial guarantees, if necessary, to ensure that the mitigation plan is fully
implemented. Financial guarantees ensuring fulfillment of the compensation project, monitoring
program, and any contingency measures must be posted in accordance with AMC 20.93.470, Financial
guarantee requirements.
(7) Approved Mitigation Projects — Signature. On completion of construction, an as -built report for any
approved mitigation project must be prepared and signed off by the applicant's qualified professional
and approved by the city. Signature of the qualified professional on the required as -built report and
approval by the Director indicates that the construction has been completed as planned.
20.93.340 Title Notification.
(a) Generally. A critical area notice on title is required, as a condition of permit issuance or project approval,
when a permit or development application is submitted for development on any property containing a
critical area or buffer. The purpose is to inform subsequent purchasers of real property of the existence of
critical areas.
(1) The title notice requirement can be met through recording of a title notice on forms prepared by the
city, establishment of a critical area tract, or recording of a native growth protection area easement,
consistent with subsections (b) through (d) of this section, as applicable.
(2) The following must be noted on all critical area title notice documents:
(A) Identification of ownership and long-term maintenance responsibility of critical areas, buffers, and
permanent field markings (e.g., fencing, signage);
(B) Restrictions on development, vegetation removal, and application of hazardous substances
(pesticides, herbicides, fertilizers) within the critical areas and buffers;
(C) The right of the city to enforce the terms of the restrictions.
(b) Title Notice. The title notice applicable to the property must be approved by the decision -maker and City
Attorney for compliance with this provision and be filed by the property owner, at their expense, with the
Snohomish County Auditor's Office. The title holder will have the right to challenge this notice and to
have it extinguished if the critical area designation no longer applies. However, the titleholder is responsible
for completing a critical area report, subject to approval by the decision -maker, before the notice on title
can be extinguished. The title notice runs with the land.
City of Arlington 20.93-28 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(c) Critical Area Tract. Subdivisions, short subdivisions, and binding site plans must establish a separate
critical area tract as a permanent protective measure for wetlands, fish and wildlife habitat conservation
areas, and geological hazard areas and their buffers. The plat or binding site plan for the project must note
the long-term ownership/maintenance responsibility as well as clearly depict the critical area tract,
including all of the subject critical area, any required buffer, and any additional lands included voluntarily
as part of the project. Should the critical area tract include several types of critical areas, separate critical
area tracts must be identified.
(d) Native Growth Protection Area (NGPA) easements. NGPA easements are required on a property where no
subdivision, short subdivision, or binding site plan is proposed or required. Unless otherwise required in
this chapter, NGPA easements must be recorded on title for all affected parcels prior to approval of a
development application or building permit, when two or more dwelling units and/or nonresidential
developments are proposed on one parcel ., to delineate and protect critical areas and their buffers. The
easement to be recorded must clearly depict the critical area(s), required buffer(s) and the limits of the
NGPA easement.
ILM'1.350 IJeld M. Lirk-_iii.
(a) Temporary Field Marking During Construction. The outer perimeter of the critical area buffer and the
clearing limits identified by an approved permit or authorization must be marked in the field with temporary
44clearing limits" fencing in such a way as to ensure that no unauthorized intrusion will occur. The marking
is subject to inspection by the Director prior to the commencement of permitted activities. This temporary
marking and fencing must be maintained throughout construction and may not be removed until permanent
fencing and/or signs, if required, are in place.
(b) Permanent Field Marking. The decision -maker may require installation of permanent signs, markers, and
fencing along the outer perimeter of a critical area or its buffer when it is determined necessary to protect
the critical areas' functions and values. Permanent markings must be installed prior to final project approval
or occupancy, as determined by the decision -maker.
(1) Signs. As a condition of any permit or authorization issued pursuant to this Chapter, the Community
and Economic Development Director shall require the applicant to install permanent signs along the
boundary of the critical area. All critical areas, tracts, easements, and dedications should be clearly
marked on the site using permanent markings, as follows:
(A) Permanent 12" x 18" signs shall be made of an enamel -coated metal face attached to a metal post
or another non -treated material of equal durability. Signs shall be posted at an interval of one (1)
every fifty (50) feet, or one (1) per lot if property owner in perpetuity. The signs shall be worded
as follows or with alternative language approved by the Community and Economic Development
Director:
Figure 1: Critical Area Protection Area Sign
THIS AREA IS PROTECTED 10 PROVIDE
WILDLIFE HABITAT AND N1A1NT.u_N
CRITICAL ARE% FUNCUON'S ,%No VNI.1 1,
PLEASE Do Noi- DISTURB
TLUS V.ALUkBLE RFSOURCE
CONTACT THE CITY OFARLINGTON
Coloa'-ITY & ECONOMIC DEVELOPMENT DEP-ARTMENT
RECARDLNG USES, RESTRICTION'S.
AND OPPORTUNTHES FOR STMARDSHIP
(B) The provisions of Subsection (A) may be modified as necessary to assure protection of sensitive
features or wildlife.
City of Arlington 20.93-29 Revised December 2025
FUMBEFFINSIREgre—fore
20.93: Critical Area Ordinance
(2) Fencing.
(A) The applicant shall be required to install a permanent fence along the boundary of the wetland
buffer when adjacent activities could degrade the wetland or its buffer (e.g., domestic animal
grazing, unauthorized access by humans or pets,
(B) Fencing installed as part of a proposed activity or as required in this subsection shall be designed
so as to not interfere with species migration or wildlife movement, including fish runs, and shall
be constructed in a manner that minimizes impacts to the wetland and associated habitat. Proposed
fencing types and materials will be determined on a case -by -case basis; however, the typical is
split rail fencing. All fencing shall be approved by the decision -maker prior to installation.
(3) Maintenance and Replacement. It is the responsibility of the landowner, successors, or as otherwise
assigned to maintain in perpetuity and replace, if necessary, all permanent fencing and field markings.
20.,..93,...,.'�'k6O,C'oiistrtictioii Plan Review.
(a) The Director may require project building and construction plans to be reviewed by a qualified professional
for confirmation of consistency with the critical area report and recommendations prior to approval of
construction plans.
(b) The Director may require monitoring by a qualified professional during site alteration activities within, or
adjacent to, critical areas or buffers, and/or a final inspection report by the quaed professional stating
that construction has or has not implemented the design recommendations provided in the project critical
area report, and evaluation of any deviation from the recommendations.
(c) When the Director determines that such services are necessary to demonstrate compliance with the
standards and guidelines of this chapter, they will be at the applicant's expense.
20.93.370 I"inancial Gtiarantee ReLlUilVinerItS.
"6iT"j4e61,_wrbonds, and other financial guarantees and associated !-erforinance
agreements or maintenance/defect/monitoring agreements are required for projects with required mitigation or
restoration of impacts to critical areas or critical area buffers consistent with the following:
(a) A performance agreement and bond, or other acceptable financial guarantees, are required from the
applicant when mitigation required pursuant to a development proposal is not completed prior to final
permit approval, such as final plat approval or final building inspection. The amount of the performance
bond(s) must equal 150 percent of the cost of the mitigation project.
(b) A performance agreement and bond, or other acceptable financial guarantees, are required from the
applicant when restoration is required for remediation of a critical area violation. The amount of the
performance bond(s) must equal 150 percent of the cost of the mitigation project.
(c) A maintenance/defect/monitoring agreement and bond, or other acceptable financial guarantees, are
required to ensure the applicant's compliance with the conditions of the approved mitigation plan pursuant
to a development proposal or restoration plan for remediation of a violation. The amount of the maintenance
bond(s) must equal 150 percent of the cost of the mitigation project in addition to the cost for monitoring
for a minimum of five years. The monitoring portion of the financial guarantee may be reduced in
proportion to work successfully completed over the period of the bond. The bonding period must coincide
with the monitoring period.
20.93380 UnaLahorized Critical Area Alterations.
,a) When a critical area or its buffer has been altered in violation of this chapter, all work must stop, and the
critical area and buffer must be restored. The Director may issue a stop work order to cease all work, and
order restoration measures at the owner's or other responsible party's expense to remediate the impacts of
the violation of the provisions of this chapter. The city may take formal enforcement action under AMC
Title 11, Violations and Abatement, to ensure the violation is abated.
City of Arlington 20.93-30 Revised December 2025
20.93390 Final Decision apd Appeals.
(a) Completion of the Critical Area Review. The city's determination regarding critical areas pursuant to this
chapter is final concurrent with the final decision to approve, condition, or deny the underlying permit for
the development proposal or other activity involved.
(b) Appeals. Any decision to approve, condition, • is a development activity proposal • • activity
based on the requirements of this chapter may be appealed according to, and as part of, the appeal procedure
for the underlying permit or approval involved.
City of Arlington 20.93-31 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
Part IV - Wetlands
34 I)cscription and- Putpo
(a) Recognize and protect the beneficial functions performed by many wetlands, which include, but are not
limited to, providing food, breeding, nesting and/or rearing habitat for fish and wildlife; recharging and
discharging ground water; contributing to stream flow during low flow periods; stabilizing stream banks
and shorelines; storing storm and flood waters to reduce flooding and erosion; carbon sequestration;
thermal refugia, and improving water quality through biofiltration, adsorption, retention, and
transformation of sediments, nutrients, and toxicants.
(b) Regulate land use to avoid adverse effects on wetlands and maintain the functions and values of wetlands
through the City of Arlington.
(c) Establish review procedures for development proposals in and adjacent to wetlands.
(1) Compliance with the provisions of this Chapter does not necessarily constitute compliance with other
federal, state, and local regulations and permit requirements that may be required (for example,
Shoreline permits, Hydraulic Project Approval permits, Clean Water Act Section 404 permits and 401
certifications, Ecology Administrative Orders, or National Pollutant Discharge Elimination System
(NPDES) permits). The applicant is responsible for complying with these requirements, apart from the
processes established in this Chapter.
2093 A 10 Identi I teation. Del ineation. Desi �-Ynation. and lZatinf-'.
,,a) Identification and Delineation. Identification of wetlands and delineation of their boundaries pursuant to
this Chapter shall be done in accordance with the approved federal wetland delineation manual and
applicable regional supplement. All areas within the city meeting the wetland definition and designation
criteria in that procedure are hereby designated critical areas and are subject to the provisions of this
Chapter. Wetland delineations are valid for five years; after such date the city shall determine whethe"
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
(b) Designation. All areas meeting the definition of a wetland and the wetland identification criteria pursuan!
to this chapter, regardless of any formal identification, are hereby designated critical areas and are subjecl
to the provisions of this chapter.
(c) Rating. Wetlands shall be rated according to the Washington state Wetland Rating System for Western
Washington: 2014 Update (Ecology Publication 14-06-029 or as revised). Wetland ratings are valid for
five years; after such date the city shall determine whether a revision or additional rating is necessary.
(1) Category 1. Category I wetlands are those that represent unique or rare wetland types, are more sensitive
to disturbance than most wetlands, are relatively undisturbed and contain ecological attributes that are
impossible to replace within a human lifetime or provide a high level of functions. The following types
of wetlands are Category 1:
(A) Relatively undisturbed estuarine wetlands larger than I acre;
(B) Wetlands of high conservation value identified by scientists of the Washington Natural Heritage
Program/Department of Natural Resources
(C) Bogs;
(D) Mature forested wetlands larger than I acre;
(E) Wetlands in coastal lagoons; and
(F) Wetland that performs many functions well and has a total score of 23 points or more in the
wetland rating.
City of Arlington 20.93-32 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(2) Category 11. Category 11 wetlands are those wetlands that are difficult, though not impossible, to
replace, and provide high levels of some functions. The following types of wetlands are Category 11:
(A) Estuarine wetlands smaller than one acre or disturbed estuarine wetlands larger than one acre;
(B) Wetlands with a moderately high level of functions and a total score of 20 to 22 points in the
wetland rating;
(C) Wetlands in coastal lagoons that are relatively undisturbed and equal to or smaller than one -tenth
acre (4,350 square feet).
(3) Category 111. Category III wetlands are those with a moderate level of functions, generally have been
disturbed in some ways, can often be adequately replaced with a well -planned mitigation project, and
are often less diverse or more isolated from other natural resources in the landscape than Category 11
wetlands. The following types of wetlands are Category III:
(A) Wetlands with a moderate level of functions with a total score of 16 to 19 points in the wetland
rating.
(4) Category IV. Category IV wetlands have the lowest levels of functions and are often heavily disturbed,
with a total score of 15 points or less in the wetland rating. The functions provided by Category IV
wetlands are generally easier to replace, and in some cases can be improved. However, experience has
shown that replacement of functions cannot be guaranteed in any specific case. These wetlands may
provide some important functions that need to be protected.
(d) Illegal Modifications. Wetland rating categories shall not change due to illegal modification made to the
wetland.
Q 3 1�aing �and D�elineat�ion
(a) Mapping. The approximate location and extent of potential wetlands are shown in the wetland data layer
maintained in the city of Arlington geographic information system (GIS). In addition, the following maps
and inventories, that depict areas of hydric soils and potential wetland areas, are hereby adopted by
reference as amended:
(1) Soil maps produced by the U.S. Department of Agriculture, National Resources Conservation Service;
and
(2) The National Wetlands Inventory, produced by the U.S. Fish and Wildlife Service.
(b) Reference Only. The maps and resources cited above are to be used as a guide for the Department, project
applicants, and/or property owners and may be continuously updated as new critical areas are identified.
They are a reference and do not provide a final critical area designation.
(c) Identification and Delineation. Identification of wetlands and delineation of their boundaries pursuant to
this chapter must be done in accordance with the adopted federal wetland delineation manual and applicable
regional supplements per WAC 173-22-035. The exact location of a wetland's boundary must be
determined through the performance of a field investigation by a qualified professional. Evidence
documenting the results of the boundary survey, including evidence of a lack of wetland indicators if no
wetlands are identified, must be submitted to the city.
20.93.430 General Development Standirds
(a) All development activities and uses are prohibited in wetlands and wetland buffers, unless administered
through the permit procedures above, and the performance standards described herein, and only when it is
demonstrated that the activity will not result in a loss of function and values of the wetland through ths
application of mitigation sequencing in AMC 20.93.330(a), Mitigation Requirements.
(b) Exemptions. Exemptions to this chapter are listed in the provisions established in AMC 20.93.250, Exemp!
Activities.
(c) Subdivisions. The subdivision and/or short subdivision of land in wetlands and associated buffers are
subject to the following:
(1) Land that is located wholly within a wetland and/or its buffer may not be subdivided; and
(2) Land that is located partially within a wetland and/or its buffer may be subdivided; provided, each lo!
will meet all zoning standards in AMC Chapter 20.48, Density and Dimensional Standards withouit
encroaching into the wetland or buffer.
City of Arlington 20.93-33 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
• Reouired Buffer Areas.
(a) Buffer Requirements. Wetland buffers must • established to protect the integrity, functions and values •
the wetland. The buffer tables below have been established in accordance with the best available science.
They are based •: the category • wetland and the habitat score (for options I and 2) as determined by a
qualified wetland professional using the Washington State Wetland Rating System for Western
Washington: 2014 r•. •"•• Publication # 14-06-029, • as revised).
City of Arlington 20.93-34 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(b) 1,Tleasurement ot
boundary as surveyed in the field. The width of the buffer must be determined according to the buffer
options chosen below.
Buffer Standards. The buffer standards re'vuired bN this chayter yresume the existence of a densg! verAetation
community in the buffer adequate to protect the wetland functions and values. When a buffer lacks adequate
vegetation, the decision -maker may increase the standard buffer, require buffer planting or other
enhancements, and/or deny a proposal for buffer reduction or buffer averaging.
(1) Buffer Width Tables.
(A) Option I
(i) Table 20.93.450-1: Wetland Buffer Width Requirements, in Feet, if Table 20.93.450-2 is
Implemented and a Habitat Corridor is Provided.
Habitat Score
Habitat Score
Habitat Score
Buffer Width Based on
Category of Wetland
3-5 Points
6-7 Points
8-9 Points
Special Characteristics
Category I or II:
Based on Rating of Wetland
75
110
225
NA
Functions (and not listed below)
Category 1:
Bogs and Wetlands of High
NA
NA
225
190
Conservation Value
Category I.
NA
NA
225
NA
Interdunal
Category L
75
110
225
NA
Forested
Category 11,
NA
NA
NA
110
Interdunal
Category 111:
60
110
225
NA
All Types Except Interdunal
Category III:
NA
NA
NA
60
Interdunal
Category IV-_
40
40
40
NA
All Types
City of Arlington 20.93-35 Revised December 2025
Buffer Reduction are Required to Address the Disturbance Through the Use of Applicable
Minimization Measures.
This is not a complete list of measures, nor is every example measure required. Though not every measure is
required for all situations, all effort should be made to implement as many measures as possible when the
activities or uses are present on the site. Regulatory staff should determine, in coordination with the applicant,
which measures are applicable and practicable.
Examples of
Activities and Uses that Cause Disturbances
Examples of Measures to Minimize Impacts
Disturbance
- Parking lots
• Direct lights away from wetland
- Commercial/Industrial
• Onlyly use lighting where necessary for public safety
Jig
- Residential
and keep lights off when not needed
- Recreation (e.g., athletic fields)
• Use motion -activated lights
- Agricultural Buildings
• Use full cut-off filters to cover light bulbs and
Lights
direct light only were needed
• Limit use of blue -white colored lights in favor of
red -amber hues
• Use lower -intensity LED lighting
• Dim light to the lowest acceptable intensity
- Commercial
• Locate activity that generates noise away from
- Industrial
wetlands
- Recreation (athletic fields, bleachers, etc.)
- Construct a fence to reduce noise impacts on
Noise
- Residential
adjacent wetland and buffer
- Agriculture
- Plant a strip of dense shrub vegetation adjacent to
wetland buffer
- Parking lots
- Route all new, untreated runoff away from wetland
- Roads
while ensuring wetland is not dewatered
- Commercial/Industrial
- Establish covenants limiting use of pesticides
- Residential areas
within 150 ft of wetland
Toxic runoff
- Application of pesticides
- Apply integrated pest management
- Landscaping
- These examples are not necessarily adequate for
- Agriculture
minimizing toxic runoff if threatened or
endangered species are present at the site
. Parking lots
- Retrofit stormwater detention and treatment for
- Roads
roads and existing adjacent development
- Residential areas
- Prevent channelized or sheet flow from lawns that
Stormwater runoff
Commercial/Industrial
directly enter the buffer
• Recreation
- Infiltrate or treat, detain, and disperse new runoff
• Landscaping/lawns
from impervious surfaces and lawns
• Other impermeable surfaces,
compacted soil, etc.
• Residential areas
- Use privacy fencing
• Recreation
- Plant dense native vegetation to delineate buffer
edge and to discourage disturbance.
- Place wetland and its buffer in a separate tract
Pets and human
- Place signs around the wetland buffer every 50 -
disturbance
200 feet and for subdivisions place signs at the
back of each residential lot
- When platting new subdivisions, locate greenbelts,
stormwater facilities, and other lower intensity
uses adjacent to wetland buffers
Dust
• Tilled fields
-Use best management practices to control dust
Roads
City of Arlington 20.93-36 Revised December 2025
(iii)Table 20.93.450-3: Wetland Buffer Width Requirements, in Feet, for Applications Not
Providing Habitat Corridor or Implementing Measures in Table 20.93.450-2.
Category of Wetland
Habitat Score Habitat Score
1
Habitat Score
TBuffer Width Based on
3-5 Points 6-7 Points
8-9 Points
Special Characteristics
Category I & 11:
Based on Rating of
100 150
300
NA
Wetland Functions (and
not listed below)
Category 1:
Bogs and Wetlands of
NA NA
300
250
High Conservation Value
Category L
NA NA
300
NA
Interdunal
Category L
100 150
300
NA
Forested
..................................... .
Category 11:
NA NA
NA
150
Interdunal
Category III:
All Types Except
80 i 150
300
NA
,—Interdunal
Category III:
Interdunal
NA NA
NA
80
Category IV:
All
50 50
50
. .. ....... . ................ ..
50
(iv) Conditions for Implementing Tables 20.93.450-1, 20.93.450-2, and 20.93.450-3
(a) Wetlands that score 6 points or more for habitat function: the buffers in Table 20.93.450-
1 can be used only if all of the following criteria are met:
(1) A relatively undisturbed, habitat corridor at least 100 feet wide is protected between
the wetland and:
(A) A legally protected, undisturbed and vegetated area (e.g., Priority Habitats,
compensatory mitigation sites, wildlife areas/refuges, federal, county, and
state parks) where they have management plans with identified areas
designated as Natural, Natural Forest, or Natural Area Preserve, or
(B) An area that is the site of a Watershed Project identified within, and fully
consistent with, a Watershed Plan is defined by RCW 89-08-460, or
(C) An area where development is prohibited according to the provisions of the
local shoreline master program, or
(D) An area with equivalent habitat quality that has conservation status in
perpetuity, in consultation with WDFW.
(2) The corridor is permanently protected for the entire distance between the wetland
and the shoreline or legally protected area by a conservation easement, deed
restriction, or other legal site protection mechanisms.
(3) Presence or absence of the shoreline or Priority Habitat must be confirmed by a
qualified biologist or shoreline Administrator.
(4) The measures in Table 20.93.450-2 are implemented, as applicable, to minimize the
impact of the adjacent land uses.
City of Arlington 20.93-37 Revised December 2025
City of Arlington 20.93-38 Revised December 2025
Title 20—Land Use Code
(7) Buffer Impacts. When buffer impacts • compensatory mitigation must be provided at a minimum
ratio of one-to-one for the area impacted. The mitigation must • • the same site when feasible or
within the same wetland system preferably. The mitigation must ensure that the wetland • and
values are • diminished due to the buffer impacts.
and IV wetland buffers if they meet all •'I the criteria identified below:
(A) The wetland is classified as a Category III or a Category IV wetland with a habitat score of three
to five points or less; and
(B) There will be "no net loss" of functions and values of the wetlands; and
(C) The wetland does not contain a breeding population of any native amphibian species; and
(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 the Department of Ecology, "Guide for Selecting
Mitigation Sites Using a Watershed Approach", or the wetland is part of a priority restoration plan
that achieves restoration goals identified in a Shoreline Master Program or other local or regional
watershed plan; and
(E) The wetland lies in the natural routing of the runoff, and the discharge follows the natural routing;
and
(F) All regulations regarding stormwater and wetland management are followed, including but not
limited to local and state wetland and stormwater codes, manual, and permits; and
(G) Modifications will require permits. Existing functions and values that are lost would have to be
compensated/rep laced through an approved mitigation plan.
paving and other hard surfacing must be set back a minimum distance of 10 feet from the edge of the
wetland buffer, or edge of the wetland if no buffer is required, unless otherwise determined by the
decision -maker that a smaller distance would meet the intent of this subsection. This setback is to avoid
• with tree branches and/or critical root • •: trees that are in the buffer • will be planted in
the buffer. The following may be allowed in the building setback from the buffer if they do not cause
damage to the critical root zone of the trees in the buffer:
♦ Landscaping;
(B) Uncovered decks, roof eaves and overhangs, unroofed stairways and steps;
(C) Pervious ground surfaces, such as driveways, patios, and parking may be allowed; provided, that
it is engineered as a permeable pavement system as defined in this chapter. Such improvements
are subject to the requirements in AMC Title 13.
1JW111ff*1P74JD-ff_ffers. Consistent with the definition of "buffer" in thjscha�
areas that are functionally isolated and physically separated from a wetland due to existing, legally
established roadways, railroads or other legally established structures or paved areas eight feet or more
in width that occur between the area in question, and the wetland must be considered physically
isolated and functionally separated buffer. One determined by the Director, based on a submitted
critical area report; to be a physically separated and functionally isolated wetland buffer, development
proposals are allowed in these areas.
'10.9',460 Critical Area ILep
(a) Additional Report Contents for Wetlands. In addition to the minimum report contents required per
AMC Critical area r• wetland -r• must also include:
(1) For each wetland identified on site and off site within 300 feet of the project site provide: the
wetland • including a description • and • for each function, per wetland ratings (AMC
20.93.410); required buffers (AMC 20.93.450); hydrogeomorphic classification; wetland acreage
based on a professional survey from the field delineation (acreages for on -site portion and entire
wetland area including off -site portions); Cowardin classification of vegetation communities;
habitat elements; soil conditions based on site assessment and/or soil survey information; and to
the extent possible, hydrologic information such as location and condition • inlets/outlets (if they
City of Arlington 20.93-39 Revised December 2025
20.93.4,70 Coinpensatom �*Vlitifzatioji Pertbrinatice Standards arld Reqtlircnients
(a) Compensatory Mitigation Plan. When a project involves wetland and/or • impacts, a
compensatory mitigation plan must be included as part of the required critical area report.
Compensatory wetland mitigation • must meet the minimum requirements • AMC 20.93.330(a),
Mitigation Requirements, and demonstrate compliance with AMC 20.93.330(b), Mitigation plan
requirements. Full guidance can be found in Wetland Mitigation in Washington State: • 2 -
Developing Mitigation Plans (Version 2.0) (Ecology Publication No. 23-06-009 • as revised and
approved by •'•• The mitigation plan must meet the following additional standards:
(1) Description of the existing wetland and buffer areas proposed to be impacted. Include acreage (or
square footage), water regime, vegetation, • landscape position, surrounding land uses, and
functions. Also describe impacts in terms of acreage by Cowardin classification, hydrogeomorphic
classification, and wetland rating, based on wetland ratings (AMC 20.93.410);
(2) Description of the compensatory mitigation site, including location and rationale for selection.
Include an assessment of existing conditions: acreage (or square footage) of wetlands and uplands,
water regime, • • water, vegetation, • landscape position, surrounding land uses, and
• Estimate future conditions in this location if the compensation • are •
undertaken (i.e., • would this site progress through natural succession);
(3) A description • the proposed • for compensation • wetland and upland areas affected •
the project. Include overall goals of the proposed mitigation, including a description of the targeted
functions, hydrogeomorphic classification, categories of wetlands, and mitigation ratios applied (if
• approach used);
City of Arlington 20.93-40 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(4) A description of the proposed mitigation construction activities, construction/installation notes, and
•' • activities;
(5) A discussion of ongoing management practices that will protect wetlands after the project site has
been developed, including proposed monitoring and maintenance programs (for remaining
wetlands and compensatory mitigation wetlands);
• Proof • establishment • • • title • the • and buffers • the project site, including
the compensatory mitigation areas; and
(7) The scaled plan sheets for the compensatory mitigation must contain, at a minimum:
(A) An accurate depiction of the existing wetland and buffers, proposed areas of wetland and/or
buffer impacts, location of proposed wetland and/or buffer compensation actions;
(B) Existing topography, ground -proofed, at two -foot contour intervals in the zone • the
proposed compensation actions if any grading activity is proposed to create the compensation
area(s). • existing cross -sections • on -site wetland. areas that are proposed to be impacted
and cross-section(s) (estimated one -foot intervals) for the proposed areas of wetland or buffer
City of Arlington 20.93-41 Revised December 2025
0
City of Arlington 20.93-42 Revised December 2025
City of Arlington 20.93-43 Revised December 2025
City of Arlington 20.93-44 Revised December 2025
Table 20.93.470-1 Wetland Mitigation Ratios
Category of
Reestablishment or Rehabilitation
Preservation
Enhancement
Impacted Wetland
Creation
tegory I
Fore
6:1 12:1
24:1
24:1
sted
Bogs
NA NA
24:1
NA
Wetlands of High
Consult with DNR Consult with
24:1
Consult with
Conservation Value
DNR
DNR
Category 1
8:1
Not Considered
Interdunal
4:1 (limited
16:1
an Option
Wetlands
circumstances)
Category 11
4:1
Not Considered
Interdunal
2:1 (limited
8:1
an Option
Wetlands
circumstances)
Category III and IV
3:1
Not Considered
Interdunal
1.5:1 1 (limited
6:1
an Option
Wetlands
L
circumstances)
Buffer Mitigation Ratios. Impacts to buffers must be mitigated at a one-to-one ratio. Compensatory
buffer mitigation must replace those buffer functions lost from development.
(k) gation Performance Standards. Wetland mitigation plans must be consistent with AMC 20.93.330
Mitigation and Mitigation P - Ian Requirements, and "Wetland Mitigation in Washington State: Part I -
Agency Policies and Guidance" (Version 2.0, Publication #23-06-009), or as revised and approved by
Ecology.
1) Minimum Standards. The design standards in this section must be incorporated into mitigation plarm,
submitted to the city for impacts to wetlands and/or wetland buffers. The following standards apply
to any mitigation proposed within Category 1, 11, 111 and IV wetlands and their buffers. Modifications
to these design standards consistent with the guidance in "Wetland Mitigation in Washington State:
Part 2 - Developing Mitigation Plans (Version 2.0)" (Ecology Publication #23-06-009, or as revised and
approved by Ecology) may be considered for approval by the decision -maker as alternatives to the
following standards:
(1) Plants native to the region (not introduced, normative or exotic species) must be used.
(2) Plant species selection must be consistent with the existing or projected hydrologic regime,
including base water levels and stormwater event fluctuations.
(3) Plant species selection must be consistent with the site environmental conditions such as slope,
aspect, soils and exposure to sun, wind and rain.
(4) Plants should be commercially available or available from local sources.
(5) Native plant species high in food and cover value for fish and wildlife should be prioritized as
appropriate for the site.
(6) Plant selection must be approved by a qualified professional.
(7) The following standards apply to wetland design and construction:
(A) For wetland creation sites, preliminary investigations of existing hydrology at the site must
be completed to confirm that the site has adequate source hydrology (e.g., high groundwater,
precipitation or riverine flooding) to support wetland conditions.
City of Arlington 20.93-45 Revised December 2025
Title 20—Land Use Code
City of Arlington 20.93-46 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
Part V. — Fish and Wildlife Habitat Conservation Areas
20.93,500 Description and EpM2��
(a) Fish and wildlife habitat conservation areas are lands managed • maintaining populations • species
in suitable habitats within their natural geographic distribution so that the habitat available is sufficient
• r•• viable populations • the long term and isolated subpopulations are not created. In
addition to their intrinsic value, certain species • fish and wildlife represent r• historic,
cultural, recreational and economic •
(b) It is the purpose • this chapter to protect fish and wildlife populations and their associated habitats
and provide special consideration to conservation or protection measures necessary to preserve or
enhance anadromous species.
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
20.93.520 Mapp'ng.
(a) Mapping. The following maps and inventories are hereby adopted by reference, as amended:
(1) Washington Department of Fish and Wildlife Priority Habitat and Species Map;
(2) Washington Department of Fish and Wildlife Priority Habitat and Species: Riparian Ecosystems and
the Online Site Potential Tree Height (SPTH) Map Tool.
(3) Washington Geological Survey, Official Water Type Reference Maps;
(4) Washington Geological Survey, Natural Heritage Program Mapping D.
(5) Anadromous and resident fish distribution maps contained in the habitat limiting factors reports
published by the Washington Conservation Commission and others;
(6) Washington Geological Survey, Natural Area Preserves and Natural Resource Conservation Area
Maps; and
(7) O. Northwest Region Critical Habitat Mapper.
(b) Reference Only. The maps and resources cited above are to be used as a guide for the city of Arlington
Community and Economic Development Department, project applicants, and/or property owners and may
be continuously updated as new critical areas are identified. They are a reference and do not provide a final
critical area designation.
City of Arlington 20.93-48 Revised December 2025
U90=1111tw7l UPWITI R
20.93: Critical Area Ordinance
I -if 71-17, "Fr
T77=1TT=L 17 19- LT v 1 60? "1 L"Mrdwl TTITT _019.7"Its"T
only if an accessible and contiguous portion of each new lot that meets the minimum lot size
requirements for the zone is located outside of the fish and wildlife habitat conservation area and
its buffer.
(3) Access roads and utilities serving a proposed subdivision may be permitted within the fish and
wildlife habitat conservation area and associated buffers only if the applicant's qualified
professional(s) demonstrate, and the decision -maker determines that no other feasible alternative
exists, all unavoidable impacts are fully mitigated, and the use is consistent with this chapter;
(4) This subsection does not authorize new access roads and utilities in fish and wildlife habitat
conservation areas and associated buffers for existing subdivisions.
N 93 (a) Type F, Type Np and Type Ns waters are critical areas for streams, creeks, and other surface water.
(b) To retain the natural functions of streams and stream corridors, the minimum riparian management zon*
widths listed in the below table shall be maintained on both sides of the waterway. All existing native
vegetation within these areas shall be preserved.
(c) Riparian management zones must:
(1) Leave native vegetation undisturbed and include identified areas for restoration, sufficient to protec!
the integrity, functions, and values of the affected stream, creek, or other surface water.
(2) Reflect the sensitivity of critical area and the type and intensity of human activity proposed to be
conducted nearby;
(3) Be consistent with the applicable species -specific management recommendations issued by the
Washington Department of Fish and Wildlife.
Figure 20.93.540-1: Riparian Management Zone Widths*
Stream Type
Required Riparian Management Zone Width Building Setback from RMZ
Type F
SPTH200 or 100 Feet, whichever is greater 15 Feet
Type Np
100 Feet 15 Feet
Type Ns
I-._._.__..._.. .
100 Feet 15 Feet
*There are streams or creeks located within the floodplain and shoreline jurisdiction that are subject to the
City of Arlington Shoreline Master Program.
(d) Development activities and uses that result in unavoidable impacts are prohibited except as otherwi-*-5
allowed by this chapter and may occur in habitat areas and associated buffers only if the propos
alteration does not degrade the functions and values of the creek, stream, or other surface water
accordance with an approved critical area report with habitat assessment/management plan, and only
the proposed activity is the least impactful alternative that will still maintain economic viability of t
property. Full compensation for the loss of acreage and functions of habitat and buffer areas must
provided in compliance with the mitigatin rfrmance standards and o requirements•f these regulation
I rface water must provide a critical are l
opeo
report prepared by a qualified professional describing the functions and values of the critical area a
buffer.
(f) Required Stream and Creek Enhancement Measures. Only those enhancement measures deemed mo
applicable and/or appropriate for enhancement projects will be considered in a modification proposal a
must be supported by best available science and a critical area report. These include, but are not limit
to: I
City of Arlington 20.93-49 Revised December 2025
Title 20—Land Use Code
Chapter 20.93: Critical Area Ordinance
(3) Planting native vegetation within the buffer area, especially vegetation that would increase value for
fish and wildlife, increase stream •.; •: slope stability, improve water quality, • provide
aesthetic/recreation value;
(4) • • modification • existing stream culverts (such as road crossings) to improve fish passage,
stream habitat, and • capacities; •
(5) Upgrading of retention/detention facilities or other stormwater management facilities beyond required
levels.
(g) To protect the natural functions and aesthetics qualities of a stream and RMZ, a detailed temporary erosion
control plan that identifies the specific mitigating measures to be implemented during construction to
protect the water from vegetation • erosion, • landslides, and r• construction
materials shall be required. The city of Arlington shall review and approve the plan with the appropriate
state, -•- and tribal agencies, and any adjacent jurisdiction.
City of Arlington 20.93-50 Revised December 2025
Figure 20.93.550-1: Arial Riparian Management Zone (RMZ) Delineation
(A) Forested RMZ RMZ delineation
Site -potential tree height
Pollution removal (100 feet)
Stream
(B) Dryland RMZ i delineation
------ Dryland riparian vegetation
- - Pollution removal (100 feet)
Z�
Stream
K Wildli _Rkparian Ecosysietro
Volume 2: Management Recommendations,
The diagram depicts an aerial view of variable width RMZ delineation process for forested (A) and
dryland (B) systems.
• Step 1: Identify the SPTH or full extent of the riparian vegetative community (green);
• Step 2: Overlay the 100 foot pollution removal distance (yellow);
• Step 3: Delineate the RMZ (black) as the greater of the two distances.
Figure 20.93.550-2: Cross Section Riparian Management Zone (RMZ) Delineation
Forested ecoregion
Dryland ecoregion
Sagebrush-
bunchgrass
Zone of Riparian Active
Riparian Zone of
Influence zone channel
zone influence
Jpfan&
Uplands
Toroved npartan 'Cosym
4ryiJnd riparian ec.W�ste.
Rqwon managtmpnt ione
Ripjf,an area
Volume 2: Management Recommendations.
The diagram depicts a cross section of the riparian management zone (RMZ)for both forested (left) and
dryland (right) ecoregions. The RMZ is coincident with the riparian ecosystem, which consists of the
riparian zone (riparian vegetative community) and the zone of influence. The riparian zone extends
from the edge of the active channel towards the uplands and it includes areas where vegetation is
influenced at least periodically by flowing waters. The zone of influence includes areas where ecological
processes significantly influence the stream, at least periodically.
City of Arlington 20.93-51 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
City of Arlington 20.93 -53 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(E) The proposal must demonstrate that the conveyance will maintain the flow capacity and not
create flooding elsewhere in the drainage basin.
(e) Riparian Management Zone Enhancement Measures. Only those enhancement measures deemed most
applicable and/or appropriate for RMZ enhancement projects will be considered in a RMZ
modification proposal and must be supported by best available science and a critical area report. These
include, but are not limited •
(1) Removal of fish barriers to restore accessibility to fish;
(2) Removal of all invasive plants (hand removal only);
(3) Enhancement of fish habitat using log structures incorporated as part of a fish habitat enhancement
•
(4) Enhancement • fish and • habitat structures that are likely to be -• by •.. including
wood duck houses, bat boxes, nesting platforms, snags, rootwads/stumps, birdhouses, and heron
nesting areas;
(5) Planting native vegetation within the buffer area, especially vegetation that would increase value
for fish and wildlife, increase stream bank or slope stability, improve water quality, or provide
• value; or
(6) Creation of a surface channel where a watercourse was previously underground, in a culvert or
pipe. Surface channels which are "daylighted" must be located within a riparian management zone
and must be designed with energy dissipating functions or channel roughness features such as
meanders and rootwads to reduce future bank failures or nearby flooding;
(7) Removal or modification of existing stream culverts (such as road crossings) to improve fish
passage, stream habitat, and flow capacities; or
(8) Upgrading of retention/detention facilities or other stormwater management facilities beyond
required levels.
WIT
WAIAMAMIM40i I I Frog L-NL-rqtZ4k-MI 01
Title 20—Land Use Code • 20.93: Critical Area Ordinance
federal regulations in place at the time • application. Whenever activities are proposed
.• to a confirmed nest territory • • roost, a bald .• habitat management
plan must be developed by a qualified professional. Activities are adjacent to managed bald
eagle sites when they are within •>•1 feet • a nest • within • mile •`1 feet) • a
shoreline • area. Approval • the activity must not • prior to consultation with
the state or federal agency with authority on bald eagle pairs and their nest.
(C) Swan Winter Feeding Sites. Swan winter feeding sites must be protected consistently with
Washington Department of Fish and Wildlife regulations and/or guidance.
20.93,570 Storniwater Nlanqgenient Facilities
Establishment • low -impact stormwater management facilities, such as stormwater dispersion outfalls
• bioswales, may be allowed within fish and wildlife .• conservation area buffers • with
the adopted • manual; provided, that:
(a) • • location is feasible;
• There will •- "no net loss" • • and values of the fish and wildlife habitat conservation area;
(c) The critical area lies in the natural routing of the runoff, and discharge follows the natural routing;
(d) Stormwater dispersion outfalls, bioswales, bioretention facilities, and other low -impact facilities
• with the adopted • manual may be allowed within the • 25 percent • the
riparian management zone when determined by a qualified professional that the location of the
facilities will enhance the riparian management zone and protect the watercourse; and
(e) Such facilities are designed consistently with the requirements of AMC Title 13.
City of Arlington 20.93 -55 Revised December 2025
20.93.590 klifigAat�iogl'-Ier�fonnagce Statidards and Reogirements.
(a) Compensatory mitigation for FWHCAs, Streams, Creeks, and Other Surface Waters must follow the
plan requirements described under AMC 20.93.330 •; and • Plan Requirements.
�b)i Ri�icarian mang ement zones and existing buffers that are degraded from %o��l cment or other
uses shall be re -vegetated.
(c) All riparian .• zones and buffers are required to be fully vegetated, at a minimum, in
accordance to Washington Department of Fish and Wildlife best available science as depicted in
Riparian Ecosystems, • 1: Science Synthesis and Management Implications.
City of Arlington 20.93-56 Revised December 2025
Title 20—Land Use Code
r r • M. F.Tr-F "ISHIMM-
Part VI. Geologically Hazardous Areas
20,93,60O.Description and fl!!Mose.
(a) Geologically hazardous areas include areas susceptible to erosion, sliding, earthquakes, liquefaction, or
other geological events. They pose a threat to health and safety of citizens when incompatible development
is sited in areas of significant hazard.
(b) The primary purpose of these regulations is to avoid and minimize potential impacts to life and property
from geologically hazards, conserve soil resources, and minimize structural damage relating to these
hazards. The purpose is accomplished through appropriate levels of study and analysis, application of
sound engineering principles, and regulation or limitation of land uses, including maintenance of existing
vegetation, regulation of clearing and grading activities, and control of stormwater.
'10.9' 610 Desi-nation.
a Areas susce tible to one or more of the following t es of hazards are desi nated as geologicall hazardous
City of Arlington 20.93-57 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(A) Areas having "high" or "moderate to high" risk of liquefaction as mapped on the Liquefaction
Susceptibility and Site Class Maps of Western Washington State by County published by the
Washington State Department of Natural Resources. These are typically underlain by
cohesionless soils of low density typically and must have a low groundwater table.
(B) Areas located within one -quarter mile • an active fault as indicated • •. maps •
described in studies by the U.S. Geologic Survey, Washington Geological Survey, or other
documents authorized by government agencies, or identified during site inspection.
(C) Those known or suspected landslide hazards referenced in subsection (a)(2) of this section.
(4) Volcanic Hazards Areas. Volcanic hazard areas are areas subject to pyroclastic flows, lava flows, debris
avalanche, and inundation by debris flows, lahars, mudflows, or related flooding resulting from
volcanic activity. Though there are no • risks identified •,1 the city and immediate
surrounding area, other than airborne particulate impacts from an eruption.
(5) Other Hazard Areas. Geologically hazardous areas may also include areas determined by the Director
to be susceptible to other geological events including mass wasting, debris flows, rock falls, and
differential settlement.
(b) All areas within the citi 11rieeting one or more of these criteria repardless of' anv formal identification, are
�11%JKMWAQ 1 K I U-0 K" N I EW 1 1K I K.M.1ro I III w 1 IJ &.AA &I m I sm E, I I &X" I rq I lu Ki
20.93.620 Mapain
(a) The following maps and resources providing information on the location and extent •.;: geologically
hazardous areas are hereby adopted by reference as amended:
(1) Snohomish County, Planning & Development Services Critical Areas Map;
Geological Survey Geologic Maps, Landslide Hazard Maps and Seismic Hazard Map;
(3) Washington Geological Survey — Geologic Information Portal
(4) Washington Geological Survey — Geologic Planning Page
(5) U.S. Department of Agriculture, National Resources Conservation Service Soil Maps;
(6) U.S. Landslide Inventory and Susceptibility (1-8-point system)
(b) Reference Only. The maps and resources cited above are to be used as a guide for the city of Arlington
Community and Economic Development Department, project applicants, and/or property owners and may
be continuously updated as new critical areas are identified. They are a reference and do not provide a final
critical area designation.
20,93,630 General DevelL)Lvient Standards,
as provided for in this chapter, and only when it is demonstrated that the activity will not create undue risk
• life, health, and safety.
Exempt Activities.
(c) Approvals. Alterations of geologically hazardous areas or associated buffers may only occur pursuant to
this chapter, and as determined by a qualified professional with concurrence by a third party review, for
activities that:
(1) Will not increase the threat of the geological hazard to adjacent properties beyond pre -development
conditions;
(2) Will not adversely impact other critical areas;
(3) Are designed so that the hazard to the project is eliminated or mitigated to a level equal to or less than
pre -development conditions; and
(4) Are determined to be safe as designed and under anticipated conditions by a qualified professional,
licensed in the state of Washington.
(d) Mitigation. Proposed mitigation techniques are considered to provide long-term hazard reduction only if
they do not require regular maintenance or other actions to maintain their function. Mitigation may be
required to avoid any increase in risk above the preexisting conditions, including following abandonment
• the activity.
City of Arlington 20.93-58 Revised December 2025
(e) Critical Facilities Prohibited. Critical facilities may not be sited within geologically hazardous areas unless
there is no other practical alternative.
11) International Building Code. All development must conforin to the provisions of the currently adopted
k
International Building Code as amended by the city of Arlington, including submittal of a critical area
report.
20,93.640 Specific Develorinient Standards.
(a) Erosion or Landslide Hazard Areas. Activities on sites containing moderate or high erosion or landslide
hazards must meet the following requirements:
(1) Setback Required. A setback must be established from all edges of moderate or high erosion or
landslide hazard areas. The size of the setback must be determined by the city to eliminate or minimize
the risk of property damage, death or injury resulting from erosion and landslides caused in whole or
part by the development, based upon review of and concurrence with a geotechnical report prepared
by a qualified professional.
(A) Minimum Setback. At the base of a slope, the setback must be equal to one-half the height of
the slope (as measured vertically from the toe to the top of the slope). For slopes less than 100
percent, the setback must be measured from the toe of slope. For slopes greater than 100 percent,
the setback must be measured from a projection of a 100 percent slope from the top of the slope
rather than the actual toe of slope. See Figure 20.93.640-1 and Figure 20.93.640-2.
(B) At the top of a slope, the setback must be equal to one-third of the height of the slope. For slopes
less than 100 percent, this setback must be measured from the top of the slope. For slopes greater
than 100 percent, this setback must be measured from the project of a 100 percent slope
originating at the toe.
Figure 20.93.640- 1: Building Setbacks From Slopes < 100%
Slope < 100%
Setback From Top of Slops:
1/3 the Height of the 51coot.
-,h-k is Measured P—
Top of Slope
setback fee. Too of Slope:
1/2 the Haight 04 the slope
Setback is Me.—nd F
T.o of Slope
Figure 20.93.640-2: Building Setbacks From Slopes > 100%
Slopes > 100% setback From Top
of Slope: 213 the
Height of the Slope
2 th. Height of the Sloe-
ple.—d F a
pmjech.n of a IOQ% Slope
[From the top of M.pt, rather Than the aural V r
of sl.p� Ho,,IghT of 51.p.
City of Arlington
Revised December 2025
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Title 20—Land Use Code
20.93: Critical Area Ordinance
City of Arlington 20.93-61 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(B) Division • land within erosion hazard areas must comply with the follow ing additional
requirements:
(i) Except as • provided in this section, existing vegetation must be retained on all lots
until building permits are approved for development on individual lots;
(ii) If any vegetation on the lots is damaged or removed during construction of the subdivision
infrastructure, the applicant must implement a revegetation plan in those areas that have been
impacted prior to final inspection • the site development permit •' the issuance • any
building permit for the subject property;
(iii) Clearing of vegetation on individual lots may be allowed prior to building permit approval
if the decision -maker 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) Stormwater output from the graded area will meet established water quality standards.
(b) Seismic Hazard Areas.
(1) Activities proposed to be located in seismic hazard areas must meet the standards of AMC 20.93.630(b)
and 20.93.630(e).
City of Arlington 20.93-63 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(A) The type and extent • geological hazard areas, any • critical areas, and recommended and
required buffers on, adjacent to, off site within 200 feet of, or that are likely to impact or be affected
by the proposal;
(B) Proposed development, including the location • existing and proposed structures, filling, clearing
limits, significant trees • be removed, vegetation to be removed, proposed material stockpile
locations, and • management facilities;
(C) The topography, in two -foot contouis of the project area and all hazard areas addressed in the
-r•
(D) Height of slope, slope gradient, and cross-section of the project area indicating the stratigraphy of
the site;
(E) The location • springs, seeps, • • surface expressions • groundwater on • • site within
200 feet • the project area • that have the r• to affect or be affected • the proposal;
that has the r• to be affected by the proposal.
City of Arlington 20.93-64 Revised December 2025
20.93: Critical Area Ordinance
Part V11. — Critical Aquifer Recharge Areas
20.93.700, Description and Pqgjs��
(a) Critical aquifer recharge areas (CARAs) provide the public with clean, safe, and available drinking water
and contribute base flows to protect aquatic resources. Once groundwater is contaminated or depleted, it
is difficult, costly, and sometimes impossible to clean up or to recharge.
(b) The purpose of this section is to protect critical aquifer recharge areas from degradation or depletion
resulting from new and redeveloping land use activities. Due to the potential vulnerability of groundwater
underlying certain aquifer recharge areas to contamination and the importance of such groundwater as
sources of public water supply, it is the intent of this section to safeguard groundwater resources by
mitigating or precluding future discharges of contaminants from new development activities and
redevelopment activities.
2 tionnaire.
(a) Applicability. The provisions of this section apply to regulated facilities that are within or adjacent to those
portions of the city of Arlington designated critical aquifer recharge areas of the city of Arlington critical
areas map. Regulated activities/facilities are defined as those commercial, industrial and home occupation
uses that:
(1) Process or handle hazardous materials in regulated quantities; and
(2) Treat or store regulated quantities of hazardous materials.
(b) Hazardous Materials Questionnaire Required. Applications for development or redevelopment of
regulated facilities within the boundaries of critical aquifer recharge areas must be accompanied by a
completed hazardous materials questionnaire to determine the regulatory status of the applicant facility.
The decision -maker must review the questionnaire to determine whether the facility is regulated under this
chapter. If it is determined that the proposal includes a regulated facility that processes, handles, treats,
and/or stores hazardous substances as defined by this chapter, the applicant must submit a critical area
report pursuant to this chapter.
20.93.720 Desianation.
(a) Critical aquifer recharge areas include:
(1) Areas served by groundwater which have been designated as a "sole source aquifer area" under the
Federal Safe Drinking Water Act;
(2) Areas within a "closed" or "low flow" stream watershed designated by the Department of Ecology
pursuant to RCW Chapter 22.
(3) Areas designated as "wellhead protection areas" pursuant to Chapter 246-290 WAC and the
groundwater contribution area pursuant to WAC 246-291-125(3)(d)(iii) or otherwise recognized by the
Director as needing wellhead protection. Wellhead protection areas include, for the purpose of this
regulation, the identified recharge areas associated with:
(A) The 10 year groundwater time -of -travel for all Group A public water supply wells; or
(B) The five year groundwater time -of -travel for all Group B public water supply wells with a wellhead
protection plan files with the Snohomish County Health Department; or
(C) Plats serviced by five or more individual wells where the average lot size is equal to or less than
two acres for which a wellhead protection plan has been completed and filed with the Snohomish
County Health Department; or
(D) The 1,000 foot radius for individual private drinking water supply wells, as identified by map
criterion in AMC 20.93.730.
City of Arlington 20.93-65 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
20,93,730 Magging.
(a) The approximate location and extent of critical aquifer recharge areas are shown on the city of Arlington
critical aquifer recharge areas and city wells map, part of the 2024 Comprehensive Plan, Book 1:
Environment, Figure E-02. In addition, the following maps and resources providing information on the
location and extent of critical aquifer recharge areas are hereby adopted by reference as amended:
(1) Areas with soils that have moderate to rapid permeability (greater than two inches per hour) as listed
in the Soil Survey of Snohomish County.
(2) Source for identifying drinking water supply wells identified by agencies such as Washington
Department of Ecology and Snohomish County Health Department
(b) Reference Only. The maps and resources cited above are to be used as a guide for the city of Arlington
Community and Economic Development Department, project applicants, and/or property owners and may
be continuously updated as new critical areas are identified. They are a reference and do not provide a final
critical area designation.
X91740
(a) Regulated activities/facilities may be permitted in a critical aquifer recharge area only if the applicant can
demonstrate that the proposed activity will not cause contaminants to enter the aquifer and that the proposed
activity will not adversely affect the recharging of the aquifer.
(b) The proposed regulated activity must comply with the water source protection requirements and
recommendations of the Federal Environmental Protection Agency, State Department of Health, and the
Snohomish County Health Department.
(c) Storage Tank Permits. The city of Arlington specifically regulates and authorizes permits for underground
storage tanks pursuant to the International Fire Code and this chapter. The Washington Department of
Ecology also regulates and authorizes permits for underground storage tanks (Chapter 173-360 WAC). The
Building Official and North County Regional Fire Authority regulate and authorize permits for the removal
of underground storage tanks.
(d) Owners and operators of facilities with existing underground storage tanks that are located within a critical
aquifer recharge area must comply with all release detection requirements as specified in Chapter 173-360
WAC.
with the adopted water or sewer comprehensive plans that have been approved by the Washington
Department of Ecology and Snohomish County Health Department.
(1) Surface spreading must meet the groundwater recharge criteria given in RCW 90.46.010(10) and
90.46.080.
(2) Direct injection must be in accordance with the standards developed by authority of RCW 90.46.042.
(f) Prohibited Activities and Land Uses. The following land uses and activities for new development or
redevelopment are prohibited within or adjacent to critical aquifer recharge areas:
(1) Landfill activities as defined in Chapters 173-304 and 173-351 WAC;
(2) All underground injection wells as defined in Chapter 173-218 WAC;
(3) Disposal of hazardous or dangerous wastes;
(4) Mining, including:
(A) Metals and hard rock mining;
(B) Sand and gravel mining are prohibited in critical aquifer recharge areas determined to be highly
susceptible or vulnerable unless a stormwater quality management plan is approved and followed
by the applicant;
(5) Wood Treatment Facilities. Wood treatment facilities that allow any portion of the treatment process
to occur over permeable surfaces (both natural and manmade);
(6) Storage, processing, or disposal of radioactive substances;
(7) Dry cleaning establishments using the solvent perchloroethylene; and
City of Arlington 20.93-66 Revised December 2025
Title 20—Land Use Code
20.93: Critical Area Ordinance
(8) 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
City of Arlington 20.93-67 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
Table 20.93.750 - 1: Statutes, Regulations and Guidance
Pertaining to Groundwater Impacting Activities
Activity
Statute - Regulation - Guidance
Above -Ground Storage Tanks
WAC 173-303-640
Animal Feedlots
Chapter 173-216 WAC, Chapter 173-220 WAC
Automobile Washers
Chapter 173-216 WAC, Best Management Practices
for Vehicle and Equipment Discharges
Below -Ground Storage Tanks
Chapter 173-360 WAC
Chemical Treatment Storage and Disposal
Chapter 173-303 WAC
Facilities
......... .. . ....... .... ...... . ...
- ------
Hazardous Waste Generator (Boat Repair
Shops, Biological Research Facility, Dry
Cleaners, Furniture Stripping, Motor Vehicle
Chapter 173-303 WAC
Service Garages, Photographic Processing,
Printing and Publishing Shops, etc.)
Injection Wells
Federal 40 CFR Part 144 and Chapter 173-218 WAC I!
Chapter 173-304 WAC, Best Management Practices i
Junk Yards and Salvage Yards
to Prevent Stonnwater Pollution at Vehicle Recycler
Facilities.
Oil and Gas Drilling
WAC 332-12-450, Chapter 173-218 WAC
Wastewater Facilities
Chapter 173-240 WAC
On -Site Sewage Systems (< 3,500 gallons/day)
Chapter 246-272A WAC, Local Health Ordinances
Large On -Site Sewage Systems
Chapter 246-272B WAC, State Health Ordinances
(3,500 to 1,000,000 gallons/day)
Pesticide Storage and Uses
Chapter 17.21 RCW
Chapter 173-303 WAC, Chapter 173-304 WAC, Best
Sawmills
Management Practices to Prevent Stormwater
Pollution at Log Yards
Solid Waste Handling and Recycling Facilities
Chapter 173-304 WAC
Surface Mining
Chapter 332-18 WAC
Chapter 173.200 WAC, Chapter 173-216 WAC, DOE
Wastewater Application to Land Surface
Land Application Guideline, Best Management
Practices for Irrigated Agriculture.
City of Arlington 20.93-68 Revised December 2025
Title 20—Land Use Code • 20.93: Critical Area Ordinance
'10.93,760 Critical Area Rcoort Additional lZequirements.
(a) Additional Report Contents for Critical Aquifer Recharge Areas, (CARAs). In addition to the minimum
report contents required per AMC 20.93.3 10, Critical Area Report, CARA reports must also include the
applicable information outlined in this section.
not limited to, the following:
(1) Information sources;
(2) Geologic and hydrologic selting including available recharge, permeabilily/transinissive information;
(3) Available well logs, borinos. seeps/springs within 1,000 t�et of the project areas-.
(4) Available water • information;
(5) Groundwater depth, flow direction and gradient based on available information;
(6) Surface water location and recharge potential;
(7) Water source supply to the site;
(8) • • scheduled necessary;
• Discussion •' the effects • the proposed project • the groundwater •
(10) Description of potential mitigation measures, should it be determined that the proposed project may
have an adverse impact on groundwater resources, and
(11) Other information as required by the city.
c) If fte c-tt-iietermines that the facilitv will have no effect on roun water resource
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City of Arlington 20.93-69 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
Part V111. Frequently Flooded Areas
20.93,800 Des����
(a) Frequently flooded areas perform important functions and may present a risk to persons and property.
(b) It is the purpose of this chapter to promote the public health, safety and general welfare, and to minimize
public and private losses due to flood conditions in specific areas caused by flooding, while protecting the
functions and values of floodplains, including special consideration for anadromous fish habitat in
combination with the provisions for fish and wildlife habitat conservation areas in this chapter.
20.93.8 10 Designation.
(a) Frequently flooded areas include those areas established as special flood hazard areas under AMC Chapter
20.64, Floodplain Development Regulations, including those areas of special flood hazard identified by the
most current Federal Insurance Rate Map (FIRM), as prepared by FEMA.
(b) Climate change and sea level rise are affecting many coastal communities and some within Puget Sound.
Applicants are urged to become familiar with potential impacts of climate change and sea level rise if
development is proposed near shorelines or associated low-lying areas.
20,93.820 Manning
(a) Reference Only. The maps and resources cited above are to be used as a guide for the city of Arlington
Community and Economic Development Department, project applicants, and/or property owners and may
be continuously updated as new critical areas are identified. They are a reference and do not provide a final
critical area designation.
20.93.830 General Develooment Standards.
(a) All development proposals must comply with AMC Chapter 20.64, Floodplain Development Regulations,
for general and specific flood hazard protection.
-Wr I ulated
activities that would reduce the flood water storage ability must be mitigated by creating compensatory
storage on or off the site.
(c) Alteration of Watercourses.
(1) Projects that propose to relocate a watercourse must also submit a request for Conditional Letter of
Map Revision (CLOMR), where required by FEMA. The project may not be approved unless FEMA
issues the CLOMR (which requires Endangered Species Act (ESA) consultation) and the provisions of
the letter are made part of the permit requirements.
(2) The decision -maker must notify adjacent communities (if applicable) and the Department of Ecology
prior to any alteration or relocation of a watercourse and submit evidence of such notification to FEMA.
(3) Maintenance must be provided within the altered or relocated portion of said watercourse so that flood
carrying capacity is not diminished. It the maintenance program does not call for cutting of native
vegetation, the system must be oversized at the time of construction to compensate for said vegetation
growth or any other natural factor that may need future maintenance.
Vanx(111114 t2a?. 21�i ';azMi g, '74�Aia%u_
including but not limited to, base flood elevations, flood protection elevation, boundary of floodplain, and
zero rise floodway.
(e) All developments must conform to the provisions of the currently adopted International Building Code,
including submittal of a critical area report.
20,93.840. Critical Area 1� - �orl A�ddifio�nalltc �uireni�ents.
(a) Additional Report Contents for frequently flooded areas. In addition to the minimum report contents
required per AMC 20.93.3 10, Critical Area Report, frequently flooded area reports must also include the
applicable information outlined in this section.
City of Arlington 20.93-70 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(b) Minimum Report Contents. A critical area report must include a habitat assessment prepared in accordance
with Regional Guidance for Floodplain Habitat Assessment and Mitigation (FEMA Region X, 2013, or as
hereafter amended. The assessment must determine if the project would adversely affect:
(1) The primary constituent elements identified with a species are listed as threatened or endangered;
(2) Essential fish habitat designated by the National Marine Fisheries Service;
(3) Fish and wildlife habitat conservation areas;
(4) Vegetation communities and habitat structures;
(5) Water quality;
(6) Water quality, including flood and low flow depths, volumes and velocities;
(7) The channel's natural planform pattern and migration processes;
(8) Spawning substrate, if applicable; and/or
(9) Floodplain refugia, if applicable.
(c) If the assessment concludes that the activity is expected to have an adverse effect on water quality and/or
aquatic or riparian habitat or habitat functions, the project must be designed in a way to offset those impacts.
Project mitigation will not be pennitted in accordance with Regional Guidance for Floodplain Habitat
Assessment and Mitigation, FEMA Region X, 2013
(d) The following activities do not require completion of a habitat assessment:
(1) Repair of existing building in its existing footprint, including damage by tire or other casualties unless
the repair constitutes substantial improvement or is necessitated by substantial damage;
(2) Removal of noxious weeds;
(3) Replacement of nonnative vegetation with native vegetation;
(4) Ongoing activities such as lawn and garden maintenance;
(5) Removal of hazard trees;
(6) Normal maintenance of public utilities and facilities;
(7) Restoration or enhancement of floodplains, riparian areas and streams that meet federal and state
stz-f-dards.
City of Arlington 20.93-71 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
a' it Description arid f"gam-
(a) The purposes of this section are to:
(1) Establish clear procedures and specific standards for preservation of cultural resources.
(2) Recognize that cultural resources may be found throughout the city and are valuable resources because
they are limited and irreplaceable.
(3) Ensure coordination and consistency with the State Environmental Policy Act (SEPA), the Shoreline
Management Act (SMA), the Growth Management Act (GMA), and the RCW Chapters 27.34, 27.44,
27.48, and 27.53.
(b) This section applies to all areas within the City of Arlington and all applications for any permits issued by
the Community and Economic Development Department.
20.93.910 Preservat ion of Cultural Resources
(a) An owner of property containing identified or probable cultural resource sites is encouraged to coordinat'i
well in advance of application for development to ensure that appropriate agencies such as the Washington
State Department of Archaeology and Historic Preservation, affected Tribes, and historic preservation
groups have ample time to assess the site and identify the potential for cultural resources.
(b) The Department must provide notice of application for a project permit consistent with AMC 20.16.230
(c) The Director may condition approval of a project permit to comply with this chapter when:
(1) The project site contains known cultural resources, as identified by any of the following;
(A) Department of Archaeology and Historic Preservation (DAHP);
(B) A Tribal government;
(C) National Register of Historic Places;
(D) Washington Heritage Register;
(2) The property is listed by DAHP as eligible for listing in either the National Register of Historic Places
or the Washington Heritage Register;
(3) The property is listed in any city register of historic places;
(4) When the city determines that reliable and credible information indicates the probable existence of an
archaeological resource or site;
(5) When a permit or approval is required for any ground -disturbing activities.
(d) The Director may condition approval of a project permit to require:
(1) Consultation with the Washington Department of Archaeology and Historical Preservation and any
affected Tribal governments;
(2) Preservation or conservation of cultural resources as required by applicable federal, state, and local
statutes.
(e) An inadvertent discovery plan shall be prepared by a professional archeologist or using the community and
economic development department's template for all ground disturbing project permits not exempted by
AMC 20.16.105.
(f) An application for development in an area known to be significant must provide for Tribal notification and
monitoring of any site disturbance, including archaeological field work and any development activity for
previously unidentified cultural resources.
20.93.920 Cultural Resource Reiva and Site Assessment
(a) The Director may require a Cultural Resource Report and Site Assessment prior to approval of development
on a property within 500 feet of a site known to contain or in an area identified as having the potential for
the presence of cultural resources or when requested by an entity identified in 20.93.910
(b) Exception: A Cultural Resource Report and Site Assessment is not required when a Cultural Resource
Management Plan is prepared pursuant to 20.93.930.
(c) A Cultural Resources Report and Site Assessment must:
City of Arlington 20.93-72 Revised December 2025
(1) Be performed by a professional archaeologist or historic preservation professional whose
documentation and methodology should be replicable by another archaeologist to reach a similar
conclusion;
(2) Use best available technology and archaeological techniques;
(3) Be based on a thorough review of records, documentation, and other relevant literature;
(4) Describe any cultural resources that are discovered on the site, using any relevant maps, written
descriptions, and photographs;
(5) Asses whether the proposed use would affect any cultural resources discovered;
,'6) Be sub
20.93.940 Inadvertent Discovery
(a) If archaeological, cultural, or historical sites or artifacts of potential significance, or human skeletal remains
are discovered in the process of development:
(1) Work on that portion of the site must be stopped immediately;
(2) The site must be secured;
City of Arlington 20.93-73 Revised December 2025
Title 20—Land Use Code Chapter 20.93: Critical Area Ordinance
(3) The discovery must be reported as soon as possible to the Community and Economic Development
Director, Washington State Department of Archaeology and Historic Preservation, affected Tribes, and
other appropriate agencies, per the approved Inadvertent Discovery Plan.
(4) The Director must require the applicant to immediately prepare a Cultural Resources Site Assessment
to determine the significance of the discovery and the extent of damage to the resource.
(b) If a Cultural Resources Site Assessment is required per subsection (a):
(1) The Director must distribute the assessment to the Washington Department of Archaeology and
Historic Preservation and affected Tribes to determine the significance of the discovery.
(2) The Director must allow 15 days for review, or 30 days in the case of inadvertent discovery of human
remains.
(3) At the conclusion of the review period:
(A) If the site has been determined not to be significant by the above listed agencies or governments,
or if the above listed agencies or governments have failed to respond, such stopped work may
resume;
(B) If the site is determined to be significant, a Cultural Resources Management Plan must be
prepared per Section 20.93.930.
(c) Treatment of cultural artifacts or human skeletal remains must comply with RCW 27.44.055, 68.50.645,
and 68.60.055.
City of Arlington 20.93-74 Revised December 2025