Objective: Cortland-Homer former MGP site w/ 7500 CY sediment removal during Phase 1.
The Homer/Cortland MGP remediation is a 2-year project encompassing the cleanup and restoration of two separate areas of the Tioughnioga River. Area 1 is a 1,700 linear foot (LF) segment adjacent to the former MGP. Area 2 is a 1,200 LF segment approximately ½ mile downstream and directly borders an active rail freight line. In each Area, DAC was tasked with creating access and staging to the river, which most notably requires the installation of a temporary bridge across the river. The Area 1 bridge in particular is a 128’ clear span bridge that was installed entirely from one side of the river. Area 2 requires a smaller bridge plus a temporary rail crossing.
To facilitate excavation, the river is being diverted with a sheetpile cofferdam that runs down the centerline of the work areas such that one-half of the river can be dewatered for earthwork. As each side of the river is enclosed, the work area is dewatered and all impacted water is sent to our on-site 1,000 GPM temporary water treatment plant. After the work area is dewatered, DAC will excavate impacted soils to depths up to 4-5’ below the riverbed and transport the material to a processing pad where it will be stabilized with lime kiln dust or Portland cement prior to shipment for offsite treatment/disposal. Tree clearing and grubbing were performed to the minimum standard necessary to complete the work, with an emphasis on leaving tree stumps intact along the riverbank for shoreline stability.
Restoration work includes a robust variety of planting and seeding zones, bank restoration details, erosion controls, and rip-rap armor. This project is strictly regulated by permit requirements for in-river work windows, flood prevention controls, and water quality monitoring.
Turbidity Control, Surface Water Quality Monitoring, and Structural Monitoring
Temporary River Bypass System and River Crossing
Water Management and Treatment
Excavated Material Handling and Management
Bank Area Restoration