The Challenge
The Snohomish Federal Navigation Channel requires periodic dredging to maintain safe navigation for commercial and maritime traffic. Before dredged sediment can be removed and disposed of, it must be evaluated to determine whether it meets environmental and regulatory requirements for open-water placement or beneficial reuse. The U.S. Army Corps of Engineers needed a comprehensive characterization of accumulated sediments to support regulatory compliance and continued channel maintenance.
Our Solution
Spheros Environmental partnered with the U.S. Army Corps of Engineers to conduct a complete dredged material characterization program. The team developed a Sampling and Analysis Plan in accordance with the Dredged Material Management Program (DMMP) User Manual, created GIS-based mapping of dredged material management units, and executed an extensive field sampling effort. Over five days, Spheros collected sediment samples using both grab and vibracore methods across 19 management units and completed the analytical testing and reporting needed to support disposal and reuse decisions.
Prime
Results +What makes this unique
Spheros successfully characterized sediment from 80 sampling locations representing 19 dredged material management units, including 62 grab samples collected in a single day. Despite challenging coarse sediment conditions that historically complicated coring efforts, the team obtained sufficient material for characterization and delivered a comprehensive report. The assessment determined that the dredged material was suitable for open-water disposal at the Port Gardner site or for beneficial use projects, supporting efficient channel maintenance and regulatory compliance.
Project Experts
