An auger digs into the top of Moose Creek Dam during a modification project at the Chena River Lakes Flood Control Project in North Pole, Alaska. The U.S. Army Corps of Engineers – Alaska District is improving the strength and stability of the dam with a mix-in-place barrier wall. Due to a dense sand and soil composition, the contractor refined its technique by using a single-column mixing method that will align successive cylindrical columns to make a wall in the center of the structure.