Critical Areas

Critical Areas Ordinance

The Critical Areas Ordinance (CAO) is intended to assist you, the land owner, in gathering environmental site information as you consider or plan for development on your property. All cities and counties under the Growth Management Act (GMA) are required to classify and designate critical areas through comprehensive planning and develop regulations to protect them. The CAO contains specific regulations to protect critical areas within the City of Centralia and its Urban Growth Areas (UGAs). As defined in the CAO, critical areas include the following categories and ecosystems: Wetlands, Fish and Wildlife Habitat Conservation Areas, Geologically Hazardous Areas - steep slopes, Frequently Flooded Areas, and Aquifer Recharge Areas.

View the Critical Areas Ordinance (Title 16: Environment).

Maps & Details


The approximate location and extent of wetlands in the city is displayed on the map titled Wetlands and Hydric Soils, 2001. This inventory is general and not designed to support permit applications, and does not establish jurisdictional boundaries. Furthermore, as site conditions change (due to natural and human processes), wetland areas and characteristics may change as well. The exact location of the wetland boundary shall be determined by a professional through the performance of a field investigation applying the wetland definition provided in this title. Wetlands shall be rated according to the Washington State Department of Ecology wetland rating system found in the Washington State Wetland Rating System for Western Washington (Department of Ecology Publication Number 4-06-025, August 2004).

View the Wetlands Map (PDF).


Hydrologists and Floodplain Managers don't like to hear a term like "100-year flood" because, scientifically, it is a misinterpretation of terminology that leads to a misconception of what a 100-year flood really is. Instead of the term "100-year flood" we would rather describe this hydrologic event as a flood having a 100-year recurrence interval. In other words, a flood of that magnitude has a 1% chance of happening in any year.

View the Floodplain Map with Elevations (PDF) and Floodplain Map Showing the Floodway (PDF).

Centralia Shorelines