Amphibious excavators guided by GNSS in bay cleanup

Photo: Topcon

Over the years, contractors involved in underwater excavation projects — dredging, pond/lake expansions, creation of boat landings, waterfront cleanups, etc. — have become some of the most ardent supporters of GNSS-based solutions. They’ve found that the ability to “see” beneath the surface with their machines has proven invaluable in improving efficiency and minimizing the risk of over/under cutting.

The Minnesota Department of Natural Resources (DNR) led the effort to remediate a section of the St. Louis River on Duluth’s waterfront. Midwest Amphibious Equipment (MAE) tackled the huge restoration project, equipping two of its amphibious excavators with Topcon HiPer VR, an FC-5000 field controller and an X-53i system.

MAE began digging out vast amounts of wood waste that had rested at the bottom of the river for more than a century, when sawmills lined the waterfront. By removing the wood waste and building a small island in the Grassy Point area, the DNR hopes to restore the damaged habitat.

The murky water required a precise method of measuring the cuts as debris was removed. “The Topcon solution lets my guys know exactly where the bucket is in relation to the plan provided by the engineers,” said MAE CEO Steve Gilbertson. “There is no guesswork; it is dead-on every time, with tolerances to 1/10 of a foot — far closer than we need it to be.”

Topcon’s SiteLink 3D provides a point-to-point communications solution. “With the click of a button I can do everything from verifying a machine’s position to sending the as-built back to the office to looking at their screen to answer a question the operator might have about the project itself,” Gilbertson said. “We’ve only scratched the surface of what can be done with SiteLink, but it’s still proving a really nice addition to our operation.”

Less than halfway into the project, MAE had removed more than 100,000 cubic yards of material.