GTA designed a modular block retaining wall to support the proposed 140,000 +/- square foot Wegmans grocery store at the Boulevard at Box Hill as well as its associated pavement areas and subsurface utilities. In conjunction with our design, GTA performed a geotechnical exploration within the area of the retaining wall to determine the subsurface conditions within the zone of influence beneath the wall. The design included both internal and global stability analyses to assess the long-term stability of the fill and underlying Potomac Clay deposit. GTA also provided construction observation and testing services during construction of the wall which required over 40,300 square feet of Keystone Standard 21.5-inch block to achieve its final dimensions of over 1,340 feet long with a maximum exposed height of over 40 feet. The drainage pipes at the base of the wall and behind the reinforced fill are interconnected and drain beneath the wall directly into the public storm drain system. The wall backfill consisted of native sand and gravel and was reinforced with Mirafi geogrid. The structural components of the wall took less than two months to construct.