KNOWLTON — The walk along the banks of the Delaware River was “tricky,” but the trekkers got what they were looking for, a chance to confirm and take pictures of, a “cave” under part of Interstate 80 as well as other maintenance concerns.
The photos taken by Chris and Tara Mezzanotte show erosion underneath a concrete wall that partially supports the interstate as it winds through the Delaware Water Gap and a collapsed drainpipe that no longer drains.
The Knowlton Township Committee has requested its professional engineer also visit the area and has scheduled time at Thursday’s committee meeting to hear from Ted Rodman on his findings.
Tara Mezzanotte said accessing the scene required a walk along a narrow, steep bit of riverbank to get close to the base of the half-mile long wall. At this time of year, with no leaves on the trees, the wall can be seen from across the river, but not the details of what they found.
Her husband, Chris, has spent his career working on and supervising highway and other transportation projects, including repair and reconstruction contracts with the New Jersey Department of Transportation.
She said he expressed concerns about what is actually behind the wall since in some places there is a hollow sound when the concrete is banged with a rock. She said they found some of the drains had been rebuilt with modern plastic pipe, but at least one of the drains has collapsed.
What they were most interested in was a “cave” that goes back under the base of the wall, apparently created by water eroding the bank.
That cave was pictured by another photographer who claimed she took pictures a couple of years ago and showed them to Department of Transportation officials last summer during an open house held by the DOT on the proposed rockfall mitigation project for the same area.
However, that photographer has not responded to requests for more information and Mezzanotte said she and her husband decided to get their own pictures and video.
In one picture, Tara Mezzanotte is shown lying down in the “cave,” while in a video clip, her husband can’t be seen until he slides out from under the wall. Another video clip shows spalling of the surface of a concrete wall, a part of the construction that created the highway.
Knowlton Mayer Adele Starrs said the photos are of concern and expected the engineer’s report to include his own assessment.
Built in the 1950s, Interstate 80 crosses the Delaware River and hugs the base of Mount Tammany, using the geologic feature of the water gap to get through the Kittatinny Ridge/Blue Ridge without tunneling or building a road up and over the nearly 1,600-foot-high ridge.
But the four-lane interstate could not be be built to the highway width standards that existed then without carving a big slice off Mount Tammany. A concrete retaining wall was constructed on the river side to create a level area on which to build the four lanes of the interstate.
The roadway structures also include a network of piping and canals to channel the massive amounts of surface drainage off the face of the mountain and from the road. The pipes go under the road surface and empty onto the bank of the Delaware River several feet below the level of the highway.
The attention on that section of Interstate 80 came as a result of the rockfall mitigation project under which the DOT proposes to build a tall steel fence to keep rocks from falling off the ledge and onto the highway. A second, 60-foot tall structure would also be constructed in an adjacent area to keep a talus slope from sliding down toward the river.
Mezzanotte is an organizer of the Facebook group I80CoalitionDWG, which claims that many of the “rockfall” incidents recorded by DOT are actually flooding or trees toppling into the road.
The I80CoalitionDWG Facebook pages make reference to DOT-documented incidentsthat flooding and subsequent icing was often a cause of accidents and lane closures through the S-curve, a stretch of highway between mileposts 1.03 and 1.45.
“They did some drainage work and now the icing is a lot less,” Mezzanotte said, adding that their trip along the riverbank showed that some of the drains are working as designed and/or rebuilt, but other areas need work, such as the area where water draining through the highway appears to be enlarging the “cave.”
She said there has been a distinct lack of communication and feedback from DOT on concerns expressed by citizens. The photographer who said she had given a picture of the “cave” to a DOT official got no response.
On Monday, the DOT press office was sent a copy of the “cave” photo by the New Jersey Herald for comment. On Tuesday, spokesman Steven Shapiro, who was not in the office on Monday, responded: “I apologize no one got back to you yesterday (Monday) to let you know we’re looking into it. I’m waiting to get information and will let you know what I find.”
As of deadline Tuesday, he had not responded further.