WAC 365-190-080   Critical areas.  (1) Wetlands. The wetlands of Washington state are fragile ecosystems which serve a number of important beneficial functions. Wetlands assist in the reduction of erosion, siltation, flooding, ground and surface water pollution, and provide wildlife, plant, and fisheries habitats. Wetlands destruction or impairment may result in increased public and private costs or property losses.

     In designating wetlands for regulatory purposes, counties and cities shall use the definition of wetlands in RCW 36.70A.030(22). Counties and cities are requested and encouraged to make their actions consistent with the intent and goals of "protection of wetlands," Executive Orders 89-10 and 90-04 as they exist on September 1, 1990. Additionally, counties and cities should consider wetlands protection guidance provided by the department of ecology including the model wetlands protection ordinance.

     (a) Counties and cities that do not now rate wetlands shall consider a wetlands rating system to reflect the relative function, value and uniqueness of wetlands in their jurisdictions. In developing wetlands rating systems, counties and cities should consider the following:

     (i) The Washington state four-tier wetlands rating system;

     (ii) Wetlands functions and values;

     (iii) Degree of sensitivity to disturbance;

     (iv) Rarity; and

     (v) Ability to compensate for destruction or degradation.

     If a county or city chooses to not use the state four-tier wetlands rating system, the rationale for that decision must be included in its next annual report to department of community development.

     (b) Counties and cities may use the National Wetlands Inventory as an information source for determining the approximate distribution and extent of wetlands. This inventory provides maps of wetland areas according to the definition of wetlands issued by the United States Department of Interior - Fish and Wildlife Service, and its wetland boundaries should be delineated for regulation consistent with the wetlands definition in RCW 36.70A.030(22).

     (c) Counties and cities should consider using the methodology in the Federal Manual for Identifying and Delineating Jurisdictional Wetlands, cooperatively produced by the United States Army Corps of Engineers, United States Environmental Protection Agency, United States Department of Agriculture Soil Conservation Service, and United States Fish and Wildlife Service, that was issued in January 1989, and regulatory guidance letter 90-7 issued by the United States Corps of Engineers on November 29, 1990, for regulatory delineations.

     (2) Aquifer recharge areas. Potable water is an essential life sustaining element. Much of Washington's drinking water comes from ground water supplies. Once ground water is contaminated it is difficult, costly, and sometimes impossible to clean up. Preventing contamination is necessary to avoid exorbitant costs, hardships, and potential physical harm to people.

     The quality of ground water in an aquifer is inextricably linked to its recharge area. Few studies have been done on aquifers and their recharge areas in Washington state. In the cases in which aquifers and their recharge areas have been studied, affected counties and cities should use this information as the base for classifying and designating these areas.

     Where no specific studies have been done, counties and cities may use existing soil and surficial geologic information to determine where recharge areas are. To determine the threat to ground water quality, existing land use activities and their potential to lead to contamination should be evaluated.

     Counties and cities shall classify recharge areas for aquifers according to the vulnerability of the aquifer. Vulnerability is the combined effect of hydrogeological susceptibility to contamination and the contamination loading potential. High vulnerability is indicated by land uses that contribute contamination that may degrade ground water, and hydrogeologic conditions that facilitate degradation. Low vulnerability is indicated by land uses that do not contribute contaminants that will degrade ground water, and by hydrogeologic conditions that do not facilitate degradation.

     (a) To characterize hydrogeologic susceptibility of the recharge area to contamination, counties and cities may consider the following physical characteristics:

     (i) Depth to ground water;

     (ii) Aquifer properties such as hydraulic conductivity and gradients;

     (iii) Soil (texture, permeability, and contaminant attenuation properties);

     (iv) Characteristics of the vadose zone including permeability and attenuation properties; and

     (v) Other relevant factors.

     (b) The following may be considered to evaluate the contaminant loading potential:

     (i) General land use;

     (ii) Waste disposal sites;

     (iii) Agriculture activities;

     (iv) Well logs and water quality test results; and

     (v) Other information about the potential for contamination.

     (c) Classification strategy for recharge areas should be to maintain the quality of the ground water, with particular attention to recharge areas of high susceptibility. In recharge areas that are highly vulnerable, studies should be initiated to determine if ground water contamination has occurred. Classification of these areas should include consideration of the degree to which the aquifer is used as a potable water source, feasibility of protective measures to preclude further degradation, availability of treatment measures to maintain potability, and availability of alternative potable water sources.

     (d) Examples of areas with a critical recharging effect on aquifers used for potable water, may include:

     (i) Sole source aquifer recharge areas designated pursuant to the Federal Safe Drinking Water Act.

     (ii) Areas established for special protection pursuant to a ground water management program, chapters 90.44, 90.48, and 90.54 RCW, and chapters 173-100 and 173-200 WAC.

     (iii) Areas designated for wellhead protection pursuant to the Federal Safe Drinking Water Act.

     (iv) Other areas meeting the definition of "areas with a critical recharging effect on aquifers used for potable water" in these guidelines.

     (3) Frequently flooded areas. Flood plains and other areas subject to flooding perform important hydrologic functions and may present a risk to persons and property. Classifications of frequently flooded areas should include, at a minimum, the 100-year flood plain designations of the Federal Emergency Management Agency and the National Flood Insurance Program.

     Counties and cities should consider the following when designating and classifying frequently flooded areas:

     (a) Effects of flooding on human health and safety, and to public facilities and services;

     (b) Available documentation including federal, state, and local laws, regulations, and programs, local studies and maps, and federal flood insurance programs;

     (c) The future flow flood plain, defined as the channel of the stream and that portion of the adjoining flood plain that is necessary to contain and discharge the base flood flow at build out without any measurable increase in flood heights;

     (d) The potential effects of tsunami, high tides with strong winds, sea level rise resulting from global climate change, and greater surface runoff caused by increasing impervious surfaces.

     (4) Geologically hazardous areas.

     (a) Geologically hazardous areas include areas susceptible to erosion, sliding, earthquake, or other geological events. They pose a threat to the health and safety of citizens when incompatible commercial, residential, or industrial development is sited in areas of significant hazard. Some geological hazards can be reduced or mitigated by engineering, design, or modified construction or mining practices so that risks to health and safety are acceptable. When technology cannot reduce risks to acceptable levels, building in geologically hazardous areas is best avoided. This distinction should be considered by counties and cities that do not now classify geological hazards as they develop their classification scheme.

     (a) Areas that are susceptible to one or more of the following types of hazards shall be classified as a geologically hazardous area:

     (i) Erosion hazard;

     (ii) Landslide hazard;

     (iii) Seismic hazard; or

     (iv) Areas subject to other geological events such as coal mine hazards and volcanic hazards including: Mass wasting, debris flows, rockfalls, and differential settlement.

     (b) Counties and cities should classify geologically hazardous area as either:

     (i) Known or suspected risk;

     (ii) No risk;

     (iii) Risk unknown - data are not available to determine the presence or absence of a geological hazard.

     (c) Erosion hazard areas are at least those areas identified by the United States Department of Agriculture Soil Conservation Service as having a "severe" rill and inter-rill erosion hazard.

     (d) Landslide hazard areas shall include areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include any areas susceptible because of any combination of bedrock, soil, slope (gradient), slope aspect, structure, hydrology, or other factors. Example of these may include, but are not limited to the following:

     (i) Areas of historic failures, such as:

     (A) Those areas delineated by the United States Department of Agriculture Soil Conservation Service as having a "severe" limitation for building site development;

     (B) Those areas mapped as class u (unstable), uos (unstable old slides), and urs (unstable recent slides) in the department of ecology coastal zone atlas; or

     (C) Areas designated as quaternary slumps, earthflows, mudflows, lahars, or landslides on maps published as the United States Geological Survey or department of natural resources division of geology and earth resources.

     (ii) Areas with all three of the following characteristics:

     (A) Slopes steeper than fifteen percent; and

     (B) Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock; and

     (C) Springs or ground water seepage;

     (iii) Areas that have shown movement during the holocene epoch (from ten thousand years ago to the present) or which are underlain or covered by mass wastage debris of that epoch;

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

     (v) Slopes having gradients steeper than eighty percent subject to rockfall during seismic shaking;

     (vi) Areas potentially unstable as a result of rapid stream incision, stream bank erosion, and undercutting by wave action;

     (vii) Areas that show evidence of, or are at risk from snow avalanches;

     (viii) Areas located in a canyon or on an active alluvial fan, presently or potentially subject to inundation by debris flows or catastrophic flooding;

     (ix) Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas composed of consolidated rock. A slope is delineated by establishing its toe and top and measured by averaging the inclination over at least ten feet of vertical relief.

     (e) Seismic hazard areas shall include areas subject to severe risk of damage as a result of earthquake induced ground shaking, slope failure, settlement, soil liquefaction, or surface faulting. One indicator of potential for future earthquake damage is a record of earthquake damage in the past. Ground shaking is the primary cause of earthquake damage in Washington. The strength of ground shaking is primarily affected by:

     (i) The magnitude of an earthquake;

     (ii) The distance from the source of an earthquake;

     (iii) The type of thickness of geologic materials at the surface; and

     (iv) The type of subsurface geologic structure.

     Settlement and soil liquefaction conditions occur in areas underlain by cohesionless soils of low density, typically in association with a shallow ground water table.

     (f) Other geological events:

     (i) Volcanic hazard areas shall include areas subject to pyroclastic flows, lava flows, debris avalanche, inundation by debris flows, mudflows, or related flooding resulting from volcanic activity.

     (ii) Mine hazard areas are those areas underlain by, adjacent to, or affected by mine workings such as adits, gangways, tunnels, drifts, or air shafts. Factors which should be considered include: Proximity to development, depth from ground surface to the mine working, and geologic material.

     (5) Fish and wildlife habitat conservation areas. Fish and wildlife habitat conservation means land management for maintaining species in suitable habitats within their natural geographic distribution so that isolated subpopulations are not created. This does not mean maintaining all individuals of all species at all times, but it does mean cooperative and coordinated land use planning is critically important among counties and cities in a region. In some cases, intergovernmental cooperation and coordination may show that it is sufficient to assure that a species will usually be found in certain regions across the state.

     (a) Fish and wildlife habitat conservation areas include:

     (i) Areas with which endangered, threatened, and sensitive species have a primary association;

     (ii) Habitats and species of local importance;

     (iii) Commercial and recreational shellfish areas;

     (iv) Kelp and eelgrass beds; herring and smelt spawning areas;

     (v) Naturally occurring ponds under twenty acres and their submerged aquatic beds that provide fish or wildlife habitat;

     (vi) Waters of the state;

     (vii) Lakes, ponds, streams, and rivers planted with game fish by a governmental or tribal entity; or

     (viii) State natural area preserves and natural resource conservation areas.

     (b) Counties and cities may consider the following when classifying and designating these areas:

     (i) Creating a system of fish and wildlife habitat with connections between larger habitat blocks and open spaces;

     (ii) Level of human activity in such areas including presence of roads and level of recreation type (passive or active recreation may be appropriate for certain areas and habitats);

     (iii) Protecting riparian ecosystems;

     (iv) Evaluating land uses surrounding ponds and fish and wildlife habitat areas that may negatively impact these areas;

     (v) Establishing buffer zones around these areas to separate incompatible uses from the habitat areas; and

     (vi) Restoring of lost salmonid habitat.

     (c) Sources and methods

     (i) Counties and cities should classify seasonal ranges and habitat elements with which federal and state listed endangered, threatened and sensitive species have a primary association and which, if altered, may reduce the likelihood that the species will maintain and reproduce over the long term.

     (ii) Counties and cities should determine which habitats and species are of local importance. Habitats and species may be further classified in terms of their relative importance.

     Counties and cities may use information prepared by the Washington department of wildlife to classify and designate locally important habitats and species. Priority habitats and priority species are being identified by the department of wildlife for all lands in Washington state. While these priorities are those of the department, they and the data on which they are based may be considered by counties and cities.

     (iii) Shellfish areas. All public and private tidelands or bedlands suitable for shellfish harvest shall be classified as critical areas. Counties and cities should consider both commercial and recreational shellfish areas. Counties and cities should at least consider the Washington department of health classification of commercial and recreational shellfish growing areas to determine the existing condition of these areas. Further consideration should be given to the vulnerability of these areas to contamination. Shellfish protection districts established pursuant to chapter 90.72 RCW shall be included in the classification of critical shellfish areas.

     (iv) Kelp and eelgrass beds; herring and smelt spawning areas. Counties and cities shall classify kelp and eelgrass beds, identified by department of natural resources aquatic lands division and the department of ecology. Though not an inclusive inventory, locations of kelp and eelgrass beds are compiled in the Puget Sound Environmental Atlas, Volumes 1 and 2. Herring and smelt spawning times and locations are outlined in WAC 220-110-240 through 220-110-260 and the Puget Sound Environmental Atlas.

     (v) Naturally occurring ponds under twenty acres and their submerged aquatic beds that provide fish or wildlife habitat.

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

     (vi) Waters of the state. Waters of the state are defined in Title 222 WAC, the forest practices rules and regulations. Counties and cities should use the classification system established in WAC 222-16-030 to classify waters of the state.

     Counties and cities may consider the following factors when classifying waters of the state as fish and wildlife habitats:

     (A) Species present which are endangered, threatened or sensitive, and other species of concern;

     (B) Species present which are sensitive to habitat manipulation;

     (C) Historic presence of species of local concern;

     (D) Existing surrounding land uses that are incompatible with salmonid habitat;

     (E) Presence and size of riparian ecosystems;

     (F) Existing water rights; and

     (G) The intermittent nature of some of the higher classes of waters of the state.

     (vii) Lakes, ponds, streams, and rivers planted with game fish.

     This includes game fish planted in these water bodies under the auspices of a federal, state, local, or tribal program or which supports priority fish species as identified by the department of wildlife.

     (viii) State natural area preserves and natural resource conservation areas. Natural area preserves and natural resource conservation areas are defined, established, and managed by department of natural resources.



[Statutory Authority: RCW 36.70A.050. 91-07-041, § 365-190-080, filed 3/15/91, effective 4/15/91.]