The Hudson River Greenway segment between 181st Street and Dyckman Street reopened two weeks ahead of schedule last week after the Parks Department wrapped up its latest attempt to fix a trail of sinkholes that has dogged the corridor for years.
The sinkhole-ridden stretch of greenway has been a pain for cyclists and pedestrians for years, with the Parks Department closing it down on at least three separate occasions in the last three years. This latest fix took the greenway offline for several weeks.
"I used this part three or four times a week before the closure," Luis Huerta, a professor at Teachers College, told Streetsblog after riding the reopened section. "This section had not really been addressed, and there was a lot of deferred maintenance."
Streetsblog visited the restored section of the greenway on Monday. Here's what we observed:
A Patchwork Fix
The newly repaved sections are smooth and much easier to ride compared to the jagged and cratered moon-like surface that defined the route for years. The repairs are easy to spot — the city filled in the holes with patches of new asphalt rather than completely redoing the path. That approach creates a patchwork of varying path quality. While there are currently no sinkholes, there are still plenty of "potholes" and root heaves in the older asphalt.
But the repairs are more than enough for Huerta and the other cyclists and pedestrians who Streetsblog spotted back on the path.
“Now that everything’s done, they’ve done an amazing job,” Huerta said.
The repairs may be janky, but the difference is striking — what was once riddled with sinkholes is now a smooth, level path.
Improving Drainage
One major contributor to the recurring sinkholes was inadequate stormwater drainage. Overly saturated sections of the dirt serve as catalysts for the formation of sinkholes.
"The grass is probably not built on concrete so the water gets in and causes destabilization," said Maggie Clarke, a local resident and environmental scientist with a background in geology. "It's right on the edge of a cliff, and if there is a hole, the water will go straight down and further destabilize the cliff."
The recent work addressed pooling from the highway onto the greenway by installing sewer grates along the route. The grates should "dispose" of water that would otherwise pool on the path and oversaturate the adjacent parkland.
Cliffside conundrum
The aging path sits on the edge of a cliff, so it's no wonder that the greenway is experiencing a sequence of sinkholes.
"Looking in geological time, the whole area will be falling down the hill," said Clarke.
She emphasized that sinkholes will continue to plague this part of the greenway until the greenway is relocated. Parks can't simply terraform the problem away.
In March, the Parks Department initiated a 12-month capital project study of the strip. In a statement to Streetsblog, officials said the agency is "exploring engineering alternatives for the restoration of the retaining wall to eliminate future sinkholes. The study includes greenway testing conducted during the current closure and community engagement starting this summer."
Root of Another Problem
A parallel strip of dirt runs along much of the greenway segment — barren, full of weeds, and with the occasional tree.
The trees look great and provide shade, but they cause issues with the infrastructure: In some areas, tree roots continue to crack and push up the asphalt, a process known as "root heave." This root upheaval makes the riding and walking surface both unpleasant and potentially unsafe for users. The recent work patched up many of the rough spots, but Streetsblog observed an old section that still has signs of root heave.
Other Issues
Other issues remain despite the repairs.
The greenway segment narrows so much that both directions of cyclists and pedestrians have to fit on a lane that is only about five feet wide. This narrow section is not long, but sits next to three lanes of car traffic and a 25-foot shoulder.
One local resident complained of a lack of lighting on the narrowest stretch.
“There are some low-visibility areas when you go around the curve, and the path is pretty narrow, which doesn't seem safe," said Elizabeth Healy, a public school teacher and resident of Washington Heights.
Huerta also mentioned how, during the closing, there was a lack of communication regarding the detour route.
"One of the unfortunate parts of the closure is that both the Parks Department and the DOT have provided very poor detour signs. I think many bicycle commuters found it very difficult to commute on Broadway, especially between Dyckman and 181st St, where traffic, double parking, and speed are big issues," Huerta said.
Potential Solutions
While the fixes to the greenway have allowed for its reopening, Clarke believes a more permanent solution is still needed. Clarke wants the Parks Department to look "outside the box" for a more permanent solution.
"You can fix this little by little and inconvenience everyone," she said.
Clarke suggested reallocating some of the vast amount of space on the highway devoted the cars to the greenway. The parkway has not suffered the same sinkhole situation as it sits further in from the cliff side and the asphalt standards seem to be much stronger and deeper, she said.
Another solution would be to extend the waterfront portion of the path up from 181st Street to connect with a currently dead-ended path at about 188th Street. Clarke floated the idea of building a pontoon-style connector path. In other parts of the world, there are examples of successful pontoon path projects that carry cyclists, pedestrians, cars, and even trains.
"They have to finish the path to nowhere," Clarke said.
