Diving And Digging Underway At Troy Seawall

Aug 15, 2018

The seawall that protects the City of Troy from the Hudson River is under an extensive renovation. WAMC’s Southern Adirondack Bureau Chief Lucas Willard got a closer look at the work underway in the Collar City.

Perhaps the person with the best view of Troy’s seawall is Mayor Patrick Madden, whose fifth floor window looks south over the Hudson River.

On this day, the river is high, swollen from heavy rains further west earlier in the week. There’s a barge on the river and workers in safety vests and hard hats below. Madden points out the curve of the river.

“If you notice here, the bend in the river, this is where the current hits that wall, it’s where the iceflows in the spring  hit that wall, and over the past hundred years, it’s carved out voids in the wall,” said Madden.

Troy’s seawall is almost 100 years old.  In May, it was announced the city would receive $14 million from the Federal Emergency Management Agency to make improvements and work started promptly.

The project is expected to take two years to complete at a total cost of $24 million.

Below Madden’s office on the riverfront, workers with contractor CD Perry are working on one section of the seawall. A new wall is actually being installed in front of the existing wall.

Jan Peterson, a resident engineer with CHA Associates, points to the tubular casing called a caisson that has been sunk into the rock below the mud beneath the surface. An enormous drill bit mounted to machinery on a floating barge is pulling sediment from within the tube.

“The caisson allows us to do this work within the tube. So we keep all the pollution out of the river. Everything – that caisson is actually screwed right down into the rock so any disturbed area stays within the tube so we don’t affect the fish.”

It’s within this tube that a steel beam called an H-Pile will be lowered and cemented into place. The H-piles will act as a sort of frame for the new section of sea wall.

A new cap will be installed on the seawall, and a 3-foot retaining wall will be placed on top, adding more flood protection. Among improvements envisioned for the waterfront, the city hopes to build a new marina in this area. There used to be docks here, before the marina was wrecked by Hurricane Irene in 2011.

While sections of the wall will be added, some will be replaced altogether.

Just a few hundred feet downriver, Peterson refers to a popular barbeque restaurant where the seawall appears like it is bending.

“See how the top of the wood dips out? See the new wood? That’s the wood collapsing right there. The wall is sunk two foot one inch. 25 inches the wall settled since it was put in in 1920, 1921,” says Peterson.

Further downriver a few hundred yards, there’s another work crew.

On another barge, parked just south of Troy’s Monument Square, there’s a metal structure. That’s where Rick Morganti is keeping his eye on two monitors. Just beside the barge, divers are underwater drilling into the seawall with a tool that resembles a small, handheld jackhammer.

“They’ve got cameras and lights. You can see each one of them working here. They’re both tied onto the radio so we can call talk at the same time, we can all talk to one-another. And they’re forming up the voids right now, getting ready to pump concrete for them,” said Morganti.

Once the divers drill into the wall, concrete will be injected to firm up the structure. A hand moves across Morganti’s monitor, but it’s difficult to see what’s happening.

“They’ve got about six to eight inches of visibility right now. They’ve had a bunch of rain. You can see the river is running pretty hard,” said Morganti.

The divers, tethered to the barge, will spend eight hours a day underwater in heated suits. Down there, they’ll come across the river’s other inhabitants like enormous catfish and eels.

Viewing the bubbles rising up from the divers’ work, Peterson says there was a 1980s-model Saab pulled from the Hudson not far from us.

“It was up against the wall, yes. There’s an old truck frame down there. Up above, these guys pulled a Suzuki motorcycle out. Bicycles. Yeah, a lot of stuff,” said Peterson.

Just today, divers found a pistol. It turned out to be a bb gun.

When the work is completed, officials hope the wall will protect the city against future flood events.

But behind a building on River Street there’s a marker placed overhead, serving as a reminder of the historic flood of March, 1913.

“That’s where the water elevation was in 1913. So we’re protecting this area from flooding but only so much we can do,” said Peterson. 

Work will continue on the seawall until winter and will resume next spring.