EA developed and managed a comprehensive dredged material management program to assess ocean placement and upland placement options for approximately 2 million cubic yards of new work material proposed for dredging for the new Midtown Tunnel connecting Portsmouth and Norfolk, Virginia. The project involved extensive coordination with the Midtown Tunnel project team, U.S. Army Corps of Engineers–Norfolk District, U.S. Environmental Protection Agency Region 3, and Virginia Department of Environmental Quality. Sampling included sonic coring to depths of from -40 to -100 feet mean lower low water and collection and analysis of materials from in-water areas, support of excavation areas, boat areas, and cut and cover areas for the tunnel construction. Evaluation included physical and chemical testing of bulk sediment and standard elutriates, ecotoxicological testing, STFATE modeling of placement events, assessment of data in relation to compliance with Section 103 of the Marine Protection Research and Sanctuaries Act for placement at the Norfolk Ocean Disposal Site, and assessment of data in relation to criteria for placement at Shirley Plantation. EA also prepared a comprehensive Dredged Material Management Plan for inclusion in the Joint Permit Application. The Dredged Material Management Plan included an assessment of available placement options; evaluation of sediment quality data evaluation in relation to placement options; a placement plan for each dredging unit; dredging and construction schedule, sequence, and equipment; results of DRDEGE modeling to assess the potential for sediment re-suspension and release of contaminants; and discussion of Best Management Practices and monitoring requirements required during dredging and in-water construction activities. EA prepared a Water Quality Monitoring Plan for dredging and in-water activities for approval by Virginia Department of Environmental Quality, Virginia Marine Resources Commission, and National Marine Fisheries Service. EA assisted with agency negotiations related to time-of-year restrictions and water quality monitoring requirements. EA also developed a Habitat Conditions Analysis to assess pre- and post-construction habitat value to assess mitigation requirements for open water habitat loss and water depth conversion. Overall, ocean placement of 90 percent of the dredged material saved the project approximately $30-40 million, and the Habitat Conditions Analysis saved the project nearly $1 million in potential mitigation costs.
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