King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle, WA 98104
giscenter@kingcounty.gov

+ 47.59909 N
- 122.33136 W

+ 47°  35' 56.72"
- 122° 19' 52.90"

 

Areas of Critical Environmental Sensitivity defined by King County CAO

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image

Description

Layer name: CRITICAL_AREAS
Subject category: enviro
Title: Areas of Critical Environmental Sensitivity defined by King County CAO
Feature Count: 2303
Feature Type: Polygon
Abstract: This layer contains critical areas & their buffers on specific parcels that have undergone Critical Area Review.Critical Areas are lands with natural hazards or lands that support certain unique, fragile or valuable resource areas. Lands designated by King County as critical include areas at high risk for with steep slopes, erosion, landslides, earthquakes, flooding; coal mines; or aquatic water features such as wetlands or lands adjoining Aquatic Areas such as streams, rivers and other water bodies.Critical Area Buffers are areas adjacent to a critical area and are also restricted from specific building and development activities.This layer is related to wetlands_area both of them are extracted from the same source material. Wetlands_area.
Purpose: The King County Code protects (CAO) CRITICAL AREAS as well as their BUFFERS in order to protect public health and safety, and to promote environmental health in the region. Buffers are areas adjacent to a critical area that are also restricted from specific building and development activities. When a development proposal occurs near wetlands, lakes, wildlife habitat or streams, an applicant may be asked to provide additional information with the permit application in order to enable the Permitting Department staff to better assess potential impacts the development might have on these critical areas.
Status: In work
Updated: As needed
Time period of content: (single date,as YYYYMMDD):: 20170428
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Yes
Place Keywords: Pacific NW, King County, WA, Washington state,
Theme Keywords: enviro, critical areas, critical habitat, regulatory, sensitive areas, critical area designation, biota, environment, geoscientificInformation,
Lineage: Available
Supplemental Information: This data was digitized from DPER field inspections that were scanned and rectified. The scans are often difficult to decipher and symbols etc. are not consistent as each surveyors has their own method and way of symbolizing and interpreting the site. Only the critical areas that are not already in one of our GIS layers were captured. If you see a wetland, seismic, landslide, erosion, floodway or wildlife corridor that is not in our GIS data please make note of it and contact the data steward so that the information can be entered. (note the scan “rectify” number ex. B07M0689_001_1R.tif or the “FEATURE_ID’ ex. 1035) so the feature can entered into the appropriate GIS data. If a scan defines a stream and calls out a “BUFFER DISTANCE “only by stating the distance the distance will sometimes be recorded with the stream line record. If the Buffer area is shown on the scan it will be captured as a polygon area stating the buffer distance. Again the buffer will not be captured unless the buffer area is shown on the scan. The BUFFER will be separate from the stream line. Building setbacks or septic setbacks are not considered CRITCIAL AREAS and are not captured in the data. Omissions: If a scan document states that data is on another document the data cannot be captured. If a document states that critical exists on that parcel but is not shown on the scan it cannot be captured. Things like: “Steep Slope onsite but not showing the boundary the data cannot becaptured.

Contacts

Maintained by:
King County Dept. of Permitting and Environmental Review
Primary: Paul McCombs, GIS Program Manager, 206-477-4514
(How to e-mail a County contact)
Secondary: KCGIS Center; giscenter@kingcounty.gov. This mailbox is monitored during business hours.

Attribute Information

ItemDescriptionDomain
_FEATURE_ID_Arbitrary unique ID. Foreign key for wetlands and CAO
Range Min:1002.0
Range Max:4061.0
_HAZARD_TYPE_Type of Senstive Area hazards
Aquatic AreaAquatic areas are defined as a non-wetland water feature including all shorelines of the state, rivers, streams, marine waters, inland bodies of open water including lakes and ponds, reservoirs and conveyance systems and impoundments of these features if any portion of the feature is formed from a stream or wetland and if any stream or wetland contributing flows is not created solely as a consequence of storm water pond construction. "Aquatic area" does not include water features that are entirely artificially collected or conveyed storm or wastewater systems or entirely artificial channels, ponds, pools or other similar constructed water feature.
Aquatic Area BufferAquatic Area Buffer,Riparian corridors provide a wide range of highly valuable functions and are essential for sustaining wild fish populations. The most common way to protect these areas is with buffers. A stream buffer is a designated area contiguous to and intended to protect and be an integral part of a stream. Buffers are generally upland areas of vegetation that protect the ecological structure and riparian function of streams from indirect impacts and from the adverse impacts of an adjacent land use. Ecological structure refers to the type, size, age of vegetation, and habitat diversity. The ecological function assessment would evaluate which function or functions the buffer or aquatic area provide and which functions would be lost or compromised rom the impact. Not all buffers perform all functions and they provide functions to varying degrees. There are several functional assessment methods that have been developed for the Pacific Northwest. Stream buffers are measured horizontally from the edge of the ordinary high water mark (OHWM) or top of the stream bank if the OHWM cannot be determined. Reference CAO Section 193.
Channel MigrationChannel migration hazards for five King County rivers: Raging River, Tolt River, Three Forks area of Snoqualmie River, Cedar River, and Green River.Areas affected by channel migration, the movement of a river or stream channel across its valley bottom, are called Channel Migration Zones (CMZs). CMZs are a type of flood hazard area and therefore a critical area under the proposed Critical Areas Ordinance (CAO). A channel migration zone consists of the river channel, the severe channel migration hazard area and the moderate channel migration hazard area. There are several rapidly migrating river systems in King County. Studies have been prepared by or for the King County Department of Natural Resources to map and describe areas of channel migration hazard on sections of five rivers: the Raging River, Tolt River, Three Forks Area of the Snoqualmie River, Cedar River, and the Green River. In each study, the maximum probable future limits of channel migration were defined using historic meander belt widths and other geomorphic features. Land within these limits is classified according to the relative degree of hazard from channel migration, based upon historic rates of channel migration and the presence of major bank protection structures that protect arterial roads and subdivision.
Channel Migration BufferChannel Migration Buffer, definition of code value [181.0] in CVD criticalareadomain_sens_hazard
Coalmine HazardCoalmine Hazard,The King County Sensitive Areas Ordinance (SAO) defines coal mine hazard areas as those areas directly underlain by or adjacent to or affected by abandoned coal mine workings such as adits (a nearly horizontal entrance to a mine), drifts (a secondary passageway between two main shafts) tunnels, or air shafts. Abandoned subsurface mine workings leave large underground voids which are hazardous in several ways. Gradual failure of the roof and sides of these voids may result in subsidence of the ground surface over a large area overlying the mines. Catastrophic failure of the roof can produce sudden and unexpected cave-ins. Noxious gases and 'dead air' (lacing oxygen) may also collect in these voids. In addition, animals or people may fall into surface openings; shafts, or tunnels. Unstable mine spoil piles, frequently covered with vegetation and resembling natural hills, pose hazards as well.
Coalmine Hazard BufferCoalmine Hazard Buffer, definition of code value [211.0] in CVD criticalareadomain_sens_hazard
Erosion HazardErosion Hazard, Erosion hazard areas are those areas thought to be underlain by soils that are subject to severe erosion when exposed. The definition for erosion hazard areas includes, but is not limited to several particular soil types that commonly erode rapidly because of the nature of their constituents and the engineering properties of the soil. The mapped extent of erosion hazard areas is based upon past regional soils mapping by several government agencies and is somewhat generalized. For this reason, specific site evaluations are sometimes necessary to quantify the actual nature and degree of erosion hazard. Often, such investigations are part of large studies that evaluate landslide or steep slope hazards. The Sensitive Ares Ordinance (SAO) defines significant erosion hazard areas as those soils in King County that may experience severe to very severe erosion hazard. The SAO adopts the soils definition in the U.S. Department of Agriculture Soil conservation Service (SCS) 1973 King County Coil Survey and the current draft of the Snoqualmie Pass Area Soil Survey (ND).
Erosion Hazard BufferErosion Hazard Buffer, definition of code value [121.0] in CVD criticalareadomain_sens_hazard
FEMA HazardFEMA Hazard,Federal Emergency Management Agency (FEMA) In March 2003, FEMA became part of the newly created U.S. Department of Homeland Security. FEMA began to formally delineate flood hazard areas along major river and stream corridors to identify areas that are at risk from floodwaters. Under the NFIP, FEMA is required to develop flood hazard information for use in both insurance rating and floodplain management.
FEMA Hazard BufferFEMA Hazard Buffer, definition of code value [171.0] in CVD criticalareadomain_sens_hazard
Flood HazardFlood Hazard, A compilation of best available floodway boundaries. A floodway is the channel of a stream plus any adjacent floodplain area that must be kept free of encroachment so that the 1 percent annual chance flood can be carried without substantial increases in flood heights.
Flood Hazard BufferFlood Hazard Buffer, definition of code value [151.0] in CVD criticalareadomain_sens_hazard
Floodway HazardFloodway Hazard,A “Regulatory Floodway” means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than a designated height. A compilation of best available floodway boundaries. A floodway is the channel of a stream plus any adjacent floodplain area that must be kept free of encroachment so that the 1 percent annual chance flood can be carried without substantial increases in flood heights. This dataset provides the location of the regulatory floodways. This information is intended for informational purposes only, and should not be used for parcel level determinations. Reference CAO Sections 137, 161, 162, 163, 164, 165, 166
Floodway Hazard BufferFloodway Hazard Buffer, definition of code value [191.0] in CVD criticalareadomain_sens_hazard
General Sensitive AreaGeneral Sensitive Area,General Sensitive Areas or General Critical area requirements implement the goals and policies of the Washington State Environmental Policy Act, the Washington State Growth Management Act and the King County Comprehensive Plan, all of which call for protection of the natural environment and public health and safety through protection of environmentally critical areas. Environmentally Critical/Sensitive Areas and at-risk resources such as landscape elements or places which are vital to the long-term maintenance of biological diversity, soil, water or other natural resources both on the site and in a regional context. They include wildlife habitat areas, steep slopes, erosion data, coal mines, etc. CAO provide critical environmental functions. For example, wetlands can protect water quality and provide fish and wildlife habitat. Our ECA code also addresses areas that represent particular challenges for development due to geologic or other natural conditions. Best Available Science: http://www.kingcounty.gov/depts/permitting-environmental-review.aspx#best
Landslide Hazard“Landslide hazard area” means those areas which are susceptible to risk of mass movement due to a combination of geologic, topographic and hydrologic factors. “Landslide” means an abrupt downslope movement of soil, rock or ground surface material. Landslide Hazard, Landslide hazards include a variety of geologic features that together present hazards to development both above and below the landslide. Such hazards include slope failures, large-scale block failures, debris flows, rock falls, rapid undercutting by stream erosion or wave action, and snow avalanches. Some landslides are readily apparent, whereas others are revealed only through careful examinations by professional investigators. The general intent of the King County Zoning Code is to encourage avoidance of landslide hazards. If avoidance is not desirable or practical, then the regulations call for scientific and engineering studies that both characterize the nature of the specific hazard and recommend ways to eliminate the hazard to the proposed development. In some cases, landslide mitigation is both straightforward and simple. In other cases, effective mitigation may be impossible or prohibitively expensive.
Landslide Hazard BufferLandslide Hazard Buffer
No DataNo Data, definition of code value [300.0] in CVD criticalareadomain_sens_hazard
OHWMOHWM,Ordinary High Water Mark (OHWM) as defined in the Shoreline Management Act (SMA) is a biological vegetation mark. Ecology's rules include a default tidal or fresh water elevation line for locations where the OHWM cannot be found.
Rock Fall HazardRock Fall Hazard, Rockfall is the falling of a newly detached mass of rock from a cliff or down a very steep slope. Rocks in a rockfall can be of any dimension, from the size of baseballs to houses. Rockfalls are the fastest type of landslide and occur most frequently in mountains or other steep areas during early spring when there is abundant moisture and repeated freezing and thawing. The rocks may freefall or carom down in an erratic sequence of tumbling, rolling and sliding. When a large number of rocks plummet downward at high velocity, it is called a rock avalanche.
Rock Fall Hazard BufferRock Fall Hazard Buffer, definition of code value [141.0] in CVD criticalareadomain_sens_hazard
Seismic HazardSeismic Hazard,The King County Sensitive Areas Ordinance (SAO) defines significant seismic hazard areas as those areas of King County subject to severe risk of earthquake damage as a result of seismically induced settlement or soil liquefaction. These conditions occur in areas underlain by cohesion-less soils of low density, usually in association with a shallow groundwater table. King County lies in the Puget Sound Lowland, an area that is subject to daily seismic activity—though most is not detectable—and is historically subject to very large earthquakes.
Seismic Hazard BufferSeismic Hazard Buffer, definition of code value [221.0] in CVD criticalareadomain_sens_hazard
Steep Slope BufferSteep Slope Buffer, definition of code value [101.0] in CVD criticalareadomain_sens_hazard
Steep Slope HazardSteep Slope Hazard,Steep slopes (meaning slopes greater than 40% grade and greater than 10 feet tall) are regulated as critical areas in King County because of the potential for erosion problems and landsliding on the slopes. The steeper the slope, the greater is the potential for hazardous conditions that threaten development and the surrounding environment. In general, the King County Zoning Code encourages avoidance of the slopes and actually prohibits development on and near the slopes in many cases. Despite this, people often choose to build near the top of a steep slope in order to gain a good view, but clearing on the slopes and in buffers around them is restricted, leading to a conflict between the wishes of developers and the requirements for slope and buffer protection. As a result, code violations resulting from slope clearing (for view creation) are numerous. Substantial revegetation (planting both trees and understory plants) may be required at sites that have been cleared illegally, sometimes resulting in significant costs to the property owner.
Volcanic HazardVolcanic HazardVolcanic hazards as addressed by King County are largely restricted to potential mudflows along stream drainages originating on Mt. Rainier. The White River upstream of Mud Mountain Dam is particularly affected. The White River downstream of the Mud Mountain Dam and other parts of the Green and Duwamish River basins are similarly affected but to a lesser degree. Other hazards related to an eruption of Mt. Rainier, such as ash falls, are not addressed by the King County Zoning Code. The single most important section of the volcanic hazards regulation is the statement at the end of the section that says, “This section shall not become effective until King County has completed the required modeling and mapping of volcanic hazard areas.” Although federal and state agencies have made some progress in volcanic hazard mapping and modeling, such work has not been done by King County and the county does not recognize other agencies' work as sufficient to fulfill the code requirement for mapping and modeling. Hence, there are effectively no development restrictions with respect to volcanic hazard areas.
Volcanic Hazard BufferVolcanic Hazard Buffer, definition of code value [131.0] in CVD criticalareadomain_sens_hazard
Wildlife AreaWildlife Area, The Wildlife Habitat Network was designed to link high quality streams and open space lands and to minimize habitat fragmentation. The goal of the network is to make sure that habitats remain connected across the landscape after development occursA wildlife habitat conservation area is an area for a species whose habitat the King County Comprehensive Plan requires the county to protect including an active breeding site and the area surrounding the breeding site that is necessary to protect breeding activity. Nine species of birds and one bat species have been identified as having habitat to protect. They include the bald eagle, great blue heron, marbled murrelet, northern goshawk, osprey, peregrine falcon, spotted owl, red-tailed hawk, and townsend’s big-eared bat. The wildlife habitat area will be identified by an expert and the results from the study will designate the wildlife habitat area regarding the presence, type, and location on the property. The development standards that apply to development proposals for each species are listed in Reference CAO Section 198.
Wildlife Area BufferWildlife Area Buffer, definition of code value [201.0] in CVD criticalareadomain_sens_hazard
Zero Rise Floodway LimitZero Rise Floodway Limit,Zero Rise Flood Limit is useful in understanding and protecting valuable riparian habitat for fish and wildlife. The zero-rise nomenclature relates to County regulations that preclude development and floodplain encroachments that would cause a measurable rise in base flood elevations. For King County, this measurable rise is calculated as an increase that is equal to or greater than 0.01 foot above the BFE. Shallow and ponded areas are included in the FEMA flood fringe. The FEMA flood fringe, combined with the FEMA floodway, constitute the regulatory FEMA 100-year floodplain. King County regulates these same areas as zero-rise floodway and zero-rise flood fringe when a specific zero-rise study has not been completed. These areas constitute the regulatory King County 100-year floodplain.
_HAZARD_SUBTYPE_Hazard subtypes are a subset of hazard type are types are a special type included within the more general hazard type. A secondary or subordinate type or genre, esp a specific one considered as falling under a general classification
AquaticAquatic,Streams are defined in the Sensitive Areas Ordinance (SAO) as those areas of King County where surface waters produce a defined channel or bed. A defined channel or bed is an area that demonstrates clear evidence of the passage of water and includes but is 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. This definition is not meant to include irrigation ditches, canals, storm or surface water runoff devices or other entirely artificial watercourses unless they are used by salmonids or used to convey streams naturally occurring prior to construction in such watercourse.
Aquatic-FAquatic-F,Type F waters include all segments of aquatic areas that are not Type S waters and that contain fish or fish habitat1, including waters diverted for use by a federal, state or tribal fish hatchery from the point of diversion for 1,500 feet or the entire tributary if the tributary is highly significant for protection of downstream water quality. Examples include: Tuck Creek, Mill Creek, Rock Creek, all lakes and ponds smaller than 20 acres that contain fish or fish habitat.
Aquatic-NAquatic-N,Type N waters include all segments of aquatic areas that are not Type S or F waters and that are physically connected to Type S or F waters by an above-ground channel2 system, stream or wetland.
Aquatic-OAquatic-O, Type O waters include all segments of aquatic areas that are not Type S, F or N waters and that are not physically connected to Type S, F or N waters by an aboveground channel system, stream or wetland.
Aquatic-SAquatic-S,Type S waters include all aquatic areas inventoried as "shorelines of the state" under King County's Shoreline Master Program, K.C.C. Title 25, in accordance with chapter 90.58 RCW, including segments of streams where the mean annual flow is more than 20 cubic feet per second, marine shorelines and lakes 20 acres in size or greater. Examples include: Puget Sound, Snoqualmie River, Ames Lake, Issaquah Creek.
Aquatic-SalmonidAquatic-Salmonid, Salmonid use can be determined by using the criteria in the Public Rule: Presumption and Rebuttal of Presumption (the public rule will be updated). The CAO has additional criteria that the department can use to determine when an area upstream of a legal human-made barrier is not fish habitat (See
Aquatic Buff-FAquatic Buff-F, definition of code value [701.0] in CVD criticalareadomain_sens_subtype
Aquatic Buff-NAquatic Buff-N, definition of code value [702.0] in CVD criticalareadomain_sens_subtype
Aquatic Buff-OAquatic Buff-O, definition of code value [703.0] in CVD criticalareadomain_sens_subtype
Aquatic Buff-SAquatic Buff-S, definition of code value [700.0] in CVD criticalareadomain_sens_subtype
Aquatic Buff-SAAquatic Buff-SA, definition of code value [704.0] in CVD criticalareadomain_sens_subtype
Aquatic Buff Unknown TypeAquatic Buff Unknown Type, definition of code value [705.0] in CVD criticalareadomain_sens_subtype
Chan Migr-MChan Migr-M; Moderate Channel Migration. Channel Migration are areas affected by channel migration, the movement of a river or stream channel across its valley bottom, are called Channel Migration Zones (CMZs). CMZs are a type of flood hazard area and therefore a critical area under the proposed Critical Areas Ordinance (CAO). A channel migration zone consists of the river channel, the severe channel migration hazard area and the moderate channel migration hazard area.
Chan Migr-PChan Migr-P; Potential Channel Migration. Channel Migration are areas affected by channel migration, the movement of a river or stream channel across its valley bottom, are called Channel Migration Zones (CMZs). CMZs are a type of flood hazard area and therefore a critical area under the proposed Critical Areas Ordinance (CAO). A channel migration zone consists of the river channel, the severe channel migration hazard area and the moderate channel migration hazard area.
Chan Migr-SChan Migr-S; Severe Channel Migration. Channel Migration are areas affected by channel migration, the movement of a river or stream channel across its valley bottom, are called Channel Migration Zones (CMZs). CMZs are a type of flood hazard area and therefore a critical area under the proposed Critical Areas Ordinance (CAO). A channel migration zone consists of the river channel, the severe channel migration hazard area and the moderate channel migration hazard area.
Chan Migr Unknown TypeChan Migr Unknown Type; Channel Migration are areas affected by channel migration, the movement of a river or stream channel across its valley bottom, are called Channel Migration Zones (CMZs). CMZs are a type of flood hazard area and therefore a critical area under the proposed Critical Areas Ordinance (CAO). A channel migration zone consists of the river channel, the severe channel migration hazard area and the moderate channel migration hazard area.
Class 2 StrmClass 2 Strm,Class 2 streams are those smaller that Class 1 streams that flow year-round during years of normal rainfall or those that are used by salmonids. Class 2S,: Smaller than Class 1 streams that flow year-round during years of normal rainfall or those that are used by salmonids. S = Salmon present. 2P: Smaller than Class 1 streams that flow year-round during years of normal rainfall or those that are used by salmonids. P = Perennial stream but no salmon.
Class 2 Strm BuffClass 2 Strm Buff, definition of code value [706.0] in CVD criticalareadomain_sens_subtype
Coalmine Haz-DECoalmine Haz-DE, DE = Declassifed Coalmine. The King County Sensitive Areas Ordinance (SAO) defines coal mine hazard areas as those areas directly underlain by or adjacent to or affected by abandoned coal mine workings such as adits (a nearly horizontal entrance to a mine), drifts (a secondary passageway between two main shafts) tunnels, or air shafts.
Coalmine Haz-MCoalmine Haz-M,M = Medium. definition of code value [901.0] in CVD criticalareadomain_sens_subtype
Coalmine Haz-SCoalmine Haz-S, definition of code value [900.0] in CVD criticalareadomain_sens_subtype
Erosion BuffErosion Buff, definition of code value [200.0] in CVD criticalareadomain_sens_subtype
Landslide BuffLandslide Buff, definition of code value [400.0] in CVD criticalareadomain_sens_subtype
N/PN/P, definition of code value [301.0] in CVD criticalareadomain_sens_subtype
No DataNo Data, definition of code value [300.0] in CVD criticalareadomain_sens_subtype
OHWM--FOHWM--F, definition of code value [507.0] in CVD criticalareadomain_sens_subtype
OHWM-NOHWM-N, definition of code value [508.0] in CVD criticalareadomain_sens_subtype
OHWM-SOHWM-S, definition of code value [506.0] in CVD criticalareadomain_sens_subtype
OHWM unknown typeOHWM unknown type, definition of code value [509.0] in CVD criticalareadomain_sens_subtype
Steep Slope BuffSteep Slope Buff, definition of code value [600.0] in CVD criticalareadomain_sens_subtype
Wildlife BuffWildlife Buff, definition of code value [101.0] in CVD criticalareadomain_sens_subtype
_HAZARD_BUFFER_Buffer in feet surrouding the hazard. May be only on one side of harzard. Not all hazards have buffers.The buffer width in feet. Stored as a whole number.
_created_date_date the record in the database was createdUNREPRESENTED DOMAIN
_last_edited_date_UNREPRESENTED DOMAIN
_Shape_Length_Length of feature in internal units.Positive real numbers that are automatically generated.


Constraints

Access: Access Constraint: Data is available on GIS Data Portal: http://www5.kingcounty.gov/gisdataportal/Default.aspx

Use: Use Constraint: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County.