Cowlitz County is mandated by the Washington State Growth Management Act to designate critical areas and adopt development regulations to assure their conservation.
Designated Critical Areas of Cowlitz County are wetlands, fish and wildlife habitat, frequently flooded areas, geologically hazardous areas and critical aquifer recharge areas.
Development activity within critical areas or their buffers is required to comply with the Cowlitz County Critical Areas Ordinance.
Fish and wildlife habitat conservation areas perform many important physical and biological functions that benefit the County and it's residents. These functions include but are not limited to providing opportunities for food, cover, nesting, breeding, and movement for fish and wildlife; maintaining and promoting diversity of species and habitat; helping to maintain air and water quality; controlling erosion, serving as areas for recreation, education and scientific study and aesthetic appreciation; providing neighborhood separation and visual diversity within urban areas, sustaining ESA-listed species, and supporting recreational and commercial fisheries.
Frequently Flooded Areas
2023 Floodplain Management Ordinance Update
Seismic hazard areas are any area subject to:
- Underlying deposits indicative of risk of liquefaction during a seismic event;
- Areas subject to slope failure, including lateral spreading, during a seismic event;
- Areas subject to surface faulting during a seismic event;
- Areas that are at risk of mass wasting due to seismic forces.
All development within seismic hazard areas must comply with the adopted International Building Code or International Residential Code.
Mine Hazard Areas:
The earliest recorded coal discovery in the State of Washington was made in 1833 near the junction of the Cowlitz and Toutle rivers (1).
Coal mining primarily occurred within the north-central part of Cowlitz County. Mine hazard areas are those areas underlain by or affected by mine workings such as adits, gangways, tunnels, drifts, or airshafts, and those areas of probably sink holes, gas releases, or subsidence due to mine workings. Locations of mine hazard areas may be known or unknown, based on best available information.
(1) Culver, Harold E., The coal fields of southwestern Washington: Washington Geol. Survey Bull. 19, p. 16, 1919.
Volcanic Hazard Areas:
The eruption of Mt. St. Helens on May 18, 1980, was the most destructive eruption in the history of the United States with respect to economic impact and loss of life and property. Portions of the Mt. St. Helens National Monument are within Cowlitz County, and the mountain is the source of four major river drainages that pass through the County to the Columbia River.
Scientists cannot precisely predict when Mt. St. Helens will erupt, the force of future eruptions, nor the area of land that will be affected. However, research does provide a record of areas that have been affected by volcanic activity throughout the volcano's history and the types of hazards that have occurred.
Cowlitz County has identified Volcanic Hazard Areas based on the Mount St. Helens Flowage-Hazard Zones Map prepared in 1995 by the United States Geological Society. These hazard areas can be subject to pyroclastic flows, lava flows, debris avalanche, and inundation by debris flows, lahars, mudflows, or related flooding resulting from volcanic activity.
Erosion Hazard Areas:
Critical Aquifer Recharge Areas
Aquifer recharge areas perform many important biological and physical functions that benefit the county and its residents, including but not limited to: storing and conveying groundwater. Protection of aquifer recharge areas is, therefore, necessary to protect the public health, safety and general welfare.