CTLGroup provided mass concrete engineering consulting services for the Blue Plains Screening and Dewatering Shafts DC Clean Rivers Project in Washington, DC. The DC Clean Rivers Project consisted of a network of tunnels designed as part of a plan to manage combined sewer overflows for the District of Columbia Water and Sewer Authority (DCWASA). The tunnels were designed to carry wastewater to the Blue Plains Advanced Water Treatment Plant. As part of the Blue Plains Project, large elements were to be constructed and the specifications required that the large elements be treated as mass concrete. The elements included base slabs (“dome slabs”), invert slabs, and walls.