US 2 Westbound Trestle Study - Environmental Considerations

The area surrounding the existing trestle presents many challenges. The structure crosses fish-bearing streams, floodplains, and wetlands. There may also be cultural resources that will require consultation with local Native American tribes and other agencies. Additional information about environmental considerations is available in the completed study.

Fish-bearing streams

This map shows rivers, streams, and irrigation channels around the US 2 trestle. These waterways serve large populations of fish species. There are also 3 fish passages on State Route 204.

Many species of fish, including Chinook salmon, chum salmon, coho salmon, pink salmon, bull trout, cutthroat trout, and steelhead trout are found throughout the study area between the Snohomish River and SR 204. These areas are presented by dashed lines on the map. In addition, there are three fish passage barriers shown as orange dots on SR 204.

 

Floodplains

This map shows the wetland areas surrounding the US 2 trestle. Much of the area is considered wetlands that include swampy or marshy areas, plants, grasses, shrubs and trees.

Ebey Island is directly under the trestle. The entire island is a floodplain. Areas of that are considered a floodway. A floodway is the channel of a river or stream and the land next to it that must remain free from obstruction so that a 100-year flood can be carried downstream. The map above shows the FEMA flood data of the Snohomish River. National flood hazard zones are indicated by various colors. Magenta indicates the floodway. The light blue represents an area with a 100-year flood risk, which means it is more likely than other areas to flood and has a 1% or greater chance to flood every year. The dark blue shading represents an area with a 500-year flood risk, meaning this area has a 0.2% likelihood to flood in a year. 

 

Wetlands 

This map shows the wetland areas surrounding the US 2 trestle. Much of the area is considered wetlands that include swampy or marshy areas, plants, grasses, shrubs and trees.

Dozens of wetlands that surround the US 2 trestle must be protected from highway storm runoff during construction. They consist mostly of swampy or marshy areas with rooted plants and grasses such as cattails, reeds and ferns, represented by light green. Other areas are dominated by woody vegetation from ground level to more than 20 feet tall, shown in darker green. The plants found in these areas include willows, alder, white pine, mature red maple and elm trees. The teal-colored section near Home Acres Road is a WSDOT wetland mitigation site.