Dredging

Dredging to Improve Environment and Economy

Ninigret Salt Marsh in Charlestown, Rhode Island, serves as a nursery for fish, a feeding ground for wading birds and a nesting area for migratory species. Rising sea levels, however, have been drowning the natural infrastructure, which acts as a buffer to storms and provides protection to area residents. As a result, vegetation in the marsh has been dying, and sand swept in by shoreline currents has been accumulating in Ninigret Pond. This accumulation of sand covers environmentally important grass beds, and also makes navigation difficult for boaters who enjoy the pond. In 2012, Hurricane Sandy also took its toll on the area.

J.F Brennan Company, Inc., a Cat® customer from La Crosse, Wisconsin, dredged two sedimentation basins, which improved navigation for boats that use the waterway and restored barrier islands that provide habitat and protect the mainland. Specially equipped low ground pressure dozers and amphibious excavators beneficially reused the sand by placing it within the salt marsh and on the island. After dredged materials were spread and graded, a variety of salt marsh grasses were planted. Over time, the grasses will cover the area, helping the marsh to recover. Both these machines enabled the crew to work effectively in areas that were too soft for conventional machines.

This natural infrastructure project made the marsh more resilient to rising sea levels, slowed the entry of sediment into the pond and improved navigation by creating a deeper channel. This means that kayakers, windsurfers, anglers and others who enjoy Ninigret Pond—and the plants and animals who call it home—will be able to do so for decades to come.

Restoring an Israeli Harbor

Thousands of miles from Rhode Island, dredging also is enhancing the natural infrastructure and the local economy. The Ashdod port in Israel is one of the country’s two main cargo ports. Located to the south of Tel Aviv, the port is undergoing a substantial expansion to increase the efficiency and productivity of Israel’s port system to satisfy a forecasted 40 percent increase in cargo traffic by 2021.

Although naturally a deep harbor, persistent exposure to the sea degrades coastal infrastructure and reduces navigation channel depths. By dredging and beneficially reusing the sand, the Ashdod Port authority intends to create new navigation channels, reclaim almost 200 acres of land from the sea, construct three new quays and improve the existing quays.

In order to protect this critical infrastructure, PMEC, a Cat® customer, will extend the existing breakwater by almost 2000 feet and construct a new breakwater that is almost 5000 feet. Digging deep below the water line and placing massive rock armour required a specialized solution. In this case, a Cat 6015B OEM long reach hydraulic shovel was optimized for this project.

The combination of the modified machine, on-site training for the operators, Cat Connect technology and services to provide real-time data about the location of equipment, fuel, engine hours and idle time, and a machine control system to enhance productivity and precision more than 15 meters under water, has enabled the Ashdod port project to stay on pace. The breakwaters this machine will construct, will provide critical protection for the port, the local community and natural infrastructure for decades.