With an important environmental window narrowing, the U.S. Army Corps of Engineers and its dredging contractor have been working around the clock to make sure a major component of the Savannah Harbor Expansion Project is completed on time. Dredging of the 20-mile-long entrance channel from 42 to 47 feet must be completed soon, as the quicker and more efficient hopper dredges can only operate during winter months, when impacts to sea turtles and endangered sturgeon are lowest.