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There are two main types of environmental surveys that are relevant to the Seattle area: wetland location surveys and environmentally critical area (ECA) surveys.

what is wetland location?

Wetland location surveys provide type, location, and size information for wetlands. They are used for resource management plans, environmental impact assessments, and habitat surveys. These surveys show the wetland’s horizontal limits and size as determined by an environment specialist in the field. ALS accurately locates this information to create a map of the wetland boundary, buffer widths, and neighboring land boundaries.

wetland location


Wetland maps are essential for planning, managing, protecting, and restoring wetlands. Relying on web-based maps for wetland status can be misleading. This is why getting a qualified surveyor to confirm critical wetlands on land is crucial to avoid additional costs and frustration.

government regulation/permitting

Obtaining building permits from the city in order to comply with local, State, and Federal regulations is critical in the result of land being on a potential wetland.

residential landowners

Landowners would need a wetland location survey that verifies the location of wetland boundaries as well as their buffer widths before a project can be approved.

what is an ECA?

ALS provides site assessments and field surveys to help project proponents with land-use planning decisions by defining the presence, extent, and quality of critical environmental areas, governed by the City of Seattle’s Environmentally Critical Areas code. This includes wetlands that protect water quality and provide wildlife habitat, as well as areas presenting challenges for development due to natural conditions. An environmental specialist may be consulted to assist ALS in defining these habitats.

what’s considered¬†a typical ECA?

If you have questions/concerns about your specific site, please consult an environmental expert to help designate your land. However, more general types of landforms that could be designated as environmentally critical areas are as follows…

geologic hazard



fish + wildlife


* ie. landslides, liquefaction, peat-settlement, seismic hazard, steep slope erosion, volcanic, etc.

** ie. riparian watercourses and management areas, priority habitats and species areas, corridors connecting priority habitat areas, etc.