Two projects to help larger cargo vessels better navigate the Seattle-Tacoma harbor have advanced to the design phase. The U.S. Army Corps of Engineers have signed design agreements with the ports of Seattle and Tacoma for the Seattle Navigation Improvement Project and the Tacoma Harbor Navigation Improvement Project, the Northwest Seaport Alliance announced Dec. 12. The project in Tacoma includes designing the deepening of Blair Waterway channel and potentially using the dredged material at the East Commencement Habitat Opportunity (formerly Saltchuk) area, while the Seattle project calls for deepening the West Waterway Channel Deepening Project to minus-57 feet mean lower…