Faced with a landfill nearing capacity, the Delaware Solid Waste Authority awarded a contract to Sevenson Environmental Services, Inc. of Niagara Falls to construct a mechanically stabilized earth berm that is being recognized for its innovative design. Sevenson was the prime contractor on the Cherry Island Landfill Vertical Expansion Project in Wilmington, Del., one of five finalists for the American Society of Civil Engineers’ 2012 award for Outstanding Civil Engineering Achievement.
Installation of a wick drain system and berm construction increased the foundation strength of the landfill from 200 pounds per square foot to 3,200 pounds per square foot. “Geosyntec’s innovative engineering solution and Sevenson’s efficient execution of the construction plan saved more than $159 million based on the original design, increased landfill capacity by 20.7 million cubic yards and extended the life of the landfill by about 20 years,” said the president and CEO of Sevenson Environmental, Michael E. Elia.
Sevenson safely worked over 350,000 man hours on the project.
The ASCE praised the project, saying, “Completion of this project represents a significant engineering achievement in view of the size of the mechanically stabilized earth berm, the depth of the layer of very soft soils over which the berm was constructed, and the unconventional design methodology.”