Boots scuff the packed dirt of the construction site, and cars whoosh past on Route 28 in Shandaken, but the dominant sound is the rhythmic pounding of the pile driver across the creek. I can see the rising and falling of the caged mechanism as a diesel hammer drills a pile deep into the ground to anchor one of the two abutments that will support the ends of a new highway bridge spanning the Esopus Creek in Mount Tremper. Thump, thump, thump all the day long.
The 800-foot bridge, to be built parallel to the 54-year-old, 336-foot-long structure on Route 28, has been designed to prevent the flooding that devastated properties and roads in Mount Tremper during Hurricane Irene in 2011. The new bridge will also be five feet higher than the old bridge. The greater height and width will allow more floodwater to pass underneath instead of blocking the flow and sending it onto the land and road.
Only one of the new bridge’s four piers will stand in the normal creek channel, instead of the three piers that caught floating tree trunks and other debris during Irene, raising the floodwaters even higher.
Shandaken suffered devastation from several floods from 2005 to 2011. In response, the New York City Department of Environmental Protection (DEP) hired engineers to conduct Local Flood Analyses (LFAs) in the township. In 2016, the Mount Tremper LFA identified measures that could prove cost-effective in preventing flooding, including removal of the disused county “green bridge” formerly linking Mount Tremper and Mount Pleasant (just recently almost completed) and of 14 homes that had been severely damaged by flooding. The report noted that replacement of the Route 28 bridge would further enhance the reduction in water height during a ten-year and even a hundred-year flood.
The old hamlet’s gone
The project involved the destruction of what had a century ago been the heart of the hamlet of Mount Tremper. FEMA and DEP offered buyouts to the owners of the flooded properties and demolished the homes.
When the aging Route 28 highway bridge was due for renovation, its inclusion in the LFA prompted the New York State Department of Transportation (DOT) to make plans for replacing it with a new bridge that would address flooding, at a price of $23.6 million.
So far the project is on schedule and is expected to be completed by late summer 2021, weather permitting. The present Route 28 bridge will remain fully open until the new bridge is ready, except for brief periods of single-lane traffic. However, the stretch of Route 212 between Wittenberg Road and Route 28, which was shut down on July 27, will be closed to through traffic for about two months unless excessive rain lengthens that closure.
The roadbed of Route 212 approaching Route 28 will be raised twelve to 13 feet and realigned at the intersection, taking over the protective role of the upstream section of rock berm which failed to protect the nearby houses in 2011.
A new bridge design
Assistant project manager Jordan Strack of the DOT said the first completed pier footing of the new Route 28 bridge, at the eastern end of the site, is set at an angle to the second pier, which is still shrouded in the forms that confine the concrete poured that morning. “It’s skewed for hydraulic reasons,” says Strack, so rising floodwaters won’t put excessive pressure on the pier.
Strack points out the coffer cell, a rectangle of corrugated metal that sits in the creek where one of the piers will be placed. The cell’s metal walls will enable water to be pumped out of the spot as the piles are driven in and the forms are set in place, so the concrete can be poured for the pier.
The longest pier is anchored by 48 piles, and the others will contain about 24 each. It takes from a few minutes to over an hour for each pile to be driven into the ground, depending on the composition of the soil, which varies from clay to rocky earth.
“The bridge has been designed,” says Strack, “so that even if the soil washes away the bridge will stay supported, and we’ll be able to keep traffic on it until repairs can be made.” After Hurricane Irene, the bridge was closed for a week while damage was repaired.
It’ll be on the Twitter feed
On top of the completed pier footing is a network of greenish rebar which will support concrete pedestals for the galvanized steel beams. DOT Region 8 public information officer Heather Pillsworth says the drama of swinging the huge beams in place will be recorded on video and posted on the agency’s Twitter feed (@nysdothv), hopefully this fall. Eventually, after further preparation, the concrete road deck will lie across the beams.
Although the project looks massive, with equipment on both sides of the creek and graded expanses of earth on either side of the highway, Pillsworth says it’s only “medium-sized” as DOT projects go in Region 8, whose nine counties range from Columbia and Ulster down to Westchester and Rockland.
On the downstream side of the bridge, a long section of berm, built by the U.S. Army Corps of Engineers in the mid-1900s, still borders the creek. However, the top five feet of the great rocks have been removed, along with the earth alongside them, leaving room for floodwaters to spread harmlessly on the floodplain, now free of buildings. Another foot of soil has been shaved off the ground to create a lower base for construction equipment. Huge mounds of dirt and rock stand at the sides of the site, waiting to be replaced when the project is completed. Then the current wasteland will be seeded with wildflowers.
For photos and updates on the progress of the Route 28 bridge construction and other DOT Region 8 projects, see the @nysdothv Twitter feed.