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CRITICAL AREAS
​​​Frequently Flooded Areas
Includes floodplains and floodways and often includes the low-lying areas adjacent to rivers and lakes that are prone to inundation during heavy rains and snowmelt.
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Floodplains 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 floodplain designations of the Federal Emergency Management Agency and the National Flood Insurance Program. Historic losses to salmon habitat have occurred as a result of development encroaching into floodplains. In addition to minimizing adverse effects to human health, safety and infrastructure, floodplains are ideal locations for salmon habitat restoration.​​
​Fish and Wildlife Habitat Conservation
Fish and wildlife habitat conservation is the management of land for maintaining species in suitable habitats within their natural geographic distribution so that isolated subpopulations are not created. This does not mean that all individuals of all species must be maintained at all times, but it does mean cooperative and coordinated land use planning is critically important among counties and cities in a region.
Wetlands
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Areas inundated by surface water or groundwater for at least part of the growing season and which support vegetation adapted for life in saturated soil conditions.
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​​​Geologically Hazardous Areas
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, fish, and wildlife, 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 in their critical areas ordinance. Counties and cities should also consider classifying geologically hazardous areas as either known or suspected risk, no risk, or unknown where data are not available to determine the presence or absence of a geological hazard.
Aquifer Recharge Areas
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. Where aquifers and their recharge areas have been studied, counties and cities should use this information as the basis for classifying and designating critical aquifer recharge areas. Where no specific hydrogeologic studies have been done, counties and cities may use existing soil, surficial geologic and well log information to determine where recharge areas are likely to be located.
Resources: The Department of Ecology provides best available science and guidance on its