Bigelow Creek Rechannelization and Habitat Enhancement.

The Bigelow Creek Rechannelization and Habitat Enhancement includes the first stage of the larger planned habitat restoration and enhancement work for the larger South Wetland Complex. Analysis of historic aerial photos and predevelopment conditions indicated that the Bigelow Creek and South Wetland Complex was historically estuarine scrub-shrub dominated wetland. The goals for the first stage of the planned restoration (Bigelow Creek Rechannelization and Habitat Enhancement) are to: (1) reestablish off-channel, intertidal habitat by removing existing undersized culverts and excavating historically filled wetlands to establish a tidally driven hydrologic regime; (2) restore Bigelow Creek to approximate its predevelopment alignment; and (3) create intertidal habitat.

The South Wetland Enhancement is divided into three work elements; intertidal wetland restoration and enhancement; Bigelow Creek realignment and constructed wetland. The City will excavate approximately 4.2 acres of the site to match new elevations ranging from minus 2 feet to plus 11 feet elevation. Most of the new intertidal habitat will be established within the plus 5 feet to plus 10 feet elevation range. Limited fill will be required to hydrologically isolate the restored wetlands from existing non-tidal. Wetland fill to construct the berms will be offset by wetland and stream creation and tidal wetland restoration and rehabilitation in the South Wetland Complex.

The initial stage of the South Wetland Complex work begins with realigning Bigelow Creek to discharge more directly to the Snohomish River. Bigelow Creek was diverted from the site sometime during the middle of the past century. Currently the stream flows through a system of excavated, channelized wetlands within existing and former railroad rights of way. Near the river, the new channel will join two small existing drainages that convey flows to the river from portions of the South Wetland Complex. The existing drainages will be habitat enhanced, and two existing culverts will be removed and the stream daylighted. Most of the length of the new stream will be tidally influenced.