International Dredging Review

International Dredging Review

In April Manson Construction Company began dredging a flow improvement channel in Chicopit Bay within the Mile Point area on the St. Johns River in Florida. The project will re-route the navigable waters in the Chicopit Bay and the Intracoastal Waterway (ICW) system. Mile Point is where the St. Johns River and the ICW meet which results in different cross-currents at ebb tide. Once Manson completes the improvement channel the project will cut off part of the existing waterway. The contrac-tor began work on the Mile Point Training Wall Reconfiguration Project in February.

Manson crews are using geo-synthetic tubes to build the marsh island perimeter foundation to restore the Great Marsh Island. The contrac-tor will place roughly 30000 tons of stone to construct the western training wall and then fill in the interior with dredged material. By April Manson had placed 20000 tons of stone 675 marine mattresses and 239 precast units for the west leg training wall.

The Mile Point project will result in the loss of 8.15 acres of salt marsh at Helen Coo-per Floyd Park which will be offset by restoring 18.84 acres of salt marsh at Great Marsh Island.  Beyond the mitigation requirement the Corps is using dredged material from the project to re-store up to a total of 53 acres of salt marsh at the island. The new west leg training wall should also substantially reduce active erosion at Great Marsh Island.

The contractor will relocate approximately 3300 feet of stone from the existing training wall at the park and build a training wall on the southeast side along the ICW. Manson will use all satisfactory stone material recovered from the existing training wall to construct the new train-ing wall.

The U.S. Army Corps of Engineers estimates that construction will continue through No-vember 2016.