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Wetlands and Streams Code


The City has adopted new Critical Areas regulations: Wetlands, Streams, Minor Lakes, Fish and Wildlife Habitat Conservation Areas and Frequently Flooded Areas (Chapter 90 Kirkland Zoning Code) as required under the state Growth Management Act (GMA) Best Available Science.

Wetland and Stream Regulations - Background:

The current regulations replace previous regulations adopted in 2002. The regulations utilize the Department of Ecology guidance on Best Available Science for wetlands and the Department of Fish and Wildlife established guidance on Best Available Science for streams and priority habitat species. The guidance better protects the functions and values of critical areas and fish and wildlife habitat conservation areas.

In Process: Minor Amendments to Wetland and Stream Code and Shoreline Master Program

The City has complied a list of wetland and stream amendments necessary since adoption in 2016. The list includes:
- Clarifications
- Modified wetland ratings and associated buffer widths based on Best Available Science
- Minor code amendments to address issues that have been identified with critical area projects.

The City will consider the list of changes in conjunction with the periodic review of the Shoreline Master Program (SMP). The intent is to bring the critical area regulations into compliance with Best Available Science through integration of the SMP and KZC Chapter 90. Please follow this link to the SMP webpage to learn more about this project, sign up to receive updates and to participate in the project.

Regulations Highlights:
  • Establishing required buffers next to wetlands and streams where new development cannot occur
  • Requiring use of mitigation sequencing: first avoid, then minimize before activities or improvements can be proposed
  • Provides options for buffer averaging but no buffer reduction
  • Establishing ratio of required wetland mitigation to area disturbed
  • Provides for mitigation off-site
  • Provides options to rebuild or enlarge certain non-conforming structures and to allow minor improvements in buffer
  • Establishes habitat protection requirements for certain sensitive species, such as eagles, herons, and woodpeckers which may limit tree removal and construction during certain times of the year
  • Establishes requirements to plant native vegetation in degraded buffers
Technical Documents:

 A Critical Areas Technical Report was used when drafting the 2016 rules and includes the following:

Review of Existing Conditions and Best Available Science (BAS):
- Provides an overview of the science relevant to the functions and values of wetlands and streams (critical areas) and a brief description of the existing critical areas in Kirkland.

Gap Analysis:
- Provides a review of the City's old critical areas regulations, noting gaps where old regulations were not consistent with Best Available Science, the Growth Management Act, and/or its implementing rules.

Wetlands, Streams and Frequently Flooded Areas FAQs and Background Information:

Background Information - Q and A:

What is best available science?

Best available science or BAS is the most current science relative to the functions and values of the critical areas, including the role of buffers in protecting wetland and stream functions and fish and wildlife. Under the GMA (RCW 36.70A.175), best available science must be used to designate and protect critical areas and to take measures to preserve and enhance anadromous fisheries, such as for salmon (i.e. fish born in fresh water which spend most of their life in the salt water and return to fresh water to spawn).

What are wetlands and what is their importance?

A wetland is an area inundated or saturated by surface or groundwater at a frequency and duration to support, under normal conditions, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. They also include artificial wetlands intentionally created from non-wetland sites as mitigation for the conversion of wetlands.

However, wetlands do not include those artificial wetlands intentionally created on non-wetland sites, including irrigation and drainage ditches, grass-lined, swales, canals, stormwater, retention and/or detention facilities, waste water treatment facilities, farm ponds and landscape amenities. Wetlands also do not include those unintentionally created after July 1, 1990, as a result of the construction of a road, street, or highway (WAC 197-11-756).

Wetlands and their associated buffers are important in that they help maintain water quality; store and convey storm and flood water; recharge ground water; provide fish and wildlife habitat; and serve as areas for recreation, education, and scientific study.

What is a wetland delineation and what is the commonly accepted rating system?

A delineation determines the boundary and type of wetland using the U.S. Army Corps of Engineers Wetland Delineation Manual (1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region Version 2.0 (Regional Supplement, Corps May 2010). The Washington Department of Ecology's Washington State Wetland Rating System is the most commonly used and regionally-accepted wetland rating system. The rating system was last updated in June 2014 (Hruby 2014; Ecology Publication NO. 14-06-019). It is a four-tier wetland rating system, which grades wetlands on a points-based  system in terms of functions and values.

What are streams and what is their importance?

A stream is an area where surface waters produce a defined channel or bed that demonstrates clear evidence of the passage of water, including but not limited to bedrock channels, gravel beds, sand and silt beds, and defined-channel swales. The channel or bed need not contain water year-round. Historic channels that are now piped or have been moved are still considered streams. Streams do not include irrigation ditches, canals, storm or surface water runoff devices, or other entirely artificial watercourses, unless they are used by salmonids or convey a naturally occurring stream that has been diverted into the artificial channel.

Streams and their associated buffers are important in that they provide important fish and wildlife habitat and travel corridors; help maintain water quality; store and convey storm and flood water; recharge groundwater; and serve as areas for recreation, education, scientific study and aesthetic appreciation.

What is a stream classification and what are the commonly accepted classification systems?

A classification determines the values and functions of a stream.

WAC 22-16-030 establishes the stream water typing system for Washington. Developed by the Department of Natural Resources, it classifies streams into four tiers:

(1) Shorelines of the state (Type S)
(2) Non-shoreline waters supporting fish habitat (Type F)
(3) Non-fish-bearing perennial streams (Type NP)
(4) Non-fish-bearing seasonal streams (Type NS)

Buffers for streams are typically measured from the ordinary high water mark.

What is a critical area buffer? What is its purpose? How does the classification system of the critical area relate to the width of the required buffer?

Critical area buffers are vegetative areas next to a wetland or stream that can protect them from or reduce the impacts of adjacent land uses. Buffers also provide wildlife habitat for wetland-dependent species that need both aquatic and terrestrial habitats for their life cycle.

Critical areWetland Buffera buffers serve several purposes: moderate runoff volume and flow rates; reduce fine sediment accumulation from erosion; remove waterborne contaminants such as excess nutrients, synthetic chemicals (e.g., pesticides, oils, and greases), and metals; provide shade for surface water temperature moderation; and provide wildlife habitat next to the critical area.

The higher the functions and values of the critical area, the greater the buffer required to protect those functions and values. 

What is a critical area buffer modification?

A critical area buffer may be reduced through a City permit by buffer width averaging (total square foot of buffer area is maintained but may be reduced in one area and enlarged in another area).  

What is mitigation sequencing?

Mitigation sequencing is a sequence of steps taken to reduce the severity of an impact to a critical area. The steps in order of preference are: avoiding the impact, minimizing the impact, rectifying the impact, reducing or eliminating the impact, compensating for the impact, and monitoring the impact and then taking appropriate corrective measures.

What is compensatory mitigation?

When unavoidable impacts occur to a wetland, compensatory mitigation is required to replace lost or impacted wetland or buffer functions. Methods of providing compensatory mitigation include restoration, establishment (creation), rehabilitation and enhancement.

What is a reasonable use exception?

A reasonable use exception is a City permit that allows limited use of a property with minimal disturbance of the sensitive area and buffer when strict application of the City’s Critical Areas Ordinance Chapter 90 KZC would deny all economically viable use of the property. Reasonable use exceptions typically arise where all or most of the site is in a critical area and/or its buffer. The area of grading and development is limited.

What are Fish and Wildlife Habitat Conservation Area?

Fish and Wildlife Habitat Conservation Areas encompass streams, small lakes, habitat for endangered, threatened, and sensitive species, and any designated habitats or species of local importance.

Within Kirkland, several salmon species (Chinook, bull trout and steelhead) are listed as federally threatened.  In addition, bald eagles are listed as State-sensitive.  These species and their habitats are addressed under the critical areas regulations.

In addition, the City has designated species or habitats of local importance. These include: Coho, Sockeye/Kokanee Salmon, Cutthroat Trout, Bald Eagle, Pileated Woodpecker and Great Blue Heron. There also is an established mechanism for designating additional species. Consult the the Washington Department of Fish and Wildlife Priority Habitat and Species map to see where these species are located. 

What are frequently flooded areas and what is their importance?

Areas within a 100-year floodplain and areas regulated by Chapter 21.56 Kirkland Municipal Code – Flood Damage Prevention.

Frequently flooded areas are important in that they help to store and convey storm and flood water; recharge ground water; provide important riparian habitat for fish and wildlife; and serve as areas for recreation, education, and scientific study. Development within and near these areas can be hazardous. Flooding also can cause substantial damage to public and private property that results in significant costs to the public and individuals.

What are the roles of Washington Department of Ecology, Washington Department Fish and Wildlife and U.S. Corps of Engineer?

Department of Ecology provides Best Available Science guidance on wetlands. Department Fish and Wildlife provides Best Available Science on streams and on priority habitat specieslinks to external site.

Most in-water projects will require permits from one or more of the following agencies: the Washington Department of Ecology, the Washington Department of Fish and Wildlife, and the Corps of Engineers.  Ecology issues permits for direct impacts to wetlands, streams and lakes. Fish and Wildlife issues permits for streams and lakes.  The Corps of Engineers issues permits for impacts to navigable waters and wetlands, streams, and lakes. If a Corps-permitted project has the potential to affect a federally listed species, the Corps will consult with the National Marine Fisheries Service and/or the U.S. Fish and Wildlife Service under the Endangered Species Act. 

Contact Kirkland Planning Department, at, 425-587-3600 if you have questions.

Planning & Building Department
123 5th Avenue, Kirkland WA 98033

General Inquiries:
Contact us via the: 
Our Kirkland Customer Service Portal
T. 425.587.3600 | F. 425.587.3232