Final Environmental Assessment: Routine Maintenance Dredging and Disposl Snohomish River Navigation Channel, Downstream and Upstream Settling Basins, Everett, Washington for Fiscal Years 2012-2018.

摘要

In accordance with the National Environmental Policy Act (NEPA), this document evaluates the potential environmental impacts of the dredging and disposal activities proposed by the Corps for routine maintenance dredging in the Snohomish River Navigation Channel for the fiscal years 2012-2018. This environmental assessment (EA) evaluates the potential impacts of conducting maintenance dredging of the downstream settling basin and adjacent portions of the navigation channel, and upstream settling basins and adjacent portions of the navigation channel and segments within the intermediate reach within the lower Snohomish River. In addition, this EA evaluates the potential impacts of disposal of the dredged material at the Washington Department of Natural Resources (WDNR) managed Puget Sound Dredged Disposal Analysis (PSDDA) open-water, non-dispersive disposal site at Port Gardner, as well as at several upland sites, including disposal at the Riverside Business Park site, the Parcel O site, and at Jetty Island. Impacts from the dredging and disposal activities will generally be highly localized in nature, short in duration, and minor in scope. While there will be a loss of subtidal habitats for benthic invertebrates and demersal fish species, this loss is expected to be temporary as these areas continuously re-shoal and benthic populations are expected to recolonize the dredged areas quickly. There will be no loss of intertidal mudflat or marsh habitats. Impacts from this navigation project should not be significant, either individually or cumulatively.