ROCKINGHAM — Worsening erosion problems affecting several businesses and roads at the Rockingham Industrial Park need a $1.32 million fix.
The erosion, which is creating unstable gullies in at least two locations, has dumped a lot of mud and debris onto the train tracks, as well, according to Rockingham Town Manager Scott Pickup.
Pickup laid the blame for the erosion on climate change, and the large storm on July 30, 2021, that dumped 5 inches of rain in the area in a short period of time. He said that storm did an enormous amount of damage, erosion wise, to the industrial park, in addition to the town’s roads.
Andres Torizzo, a hydrologist and engineer with Watershed Consulting Inc., of Burlington, said the gully developing near Spencer Drive is the more serious of the two, but he said the fix would be more limited because of space constraints.
The town will be applying for a $1 million Agency of Transportation grant to install a stormwater runoff collection system.
Pickup, in a follow-up interview, said the problem in back of Chroma Technology is serious, because the steep bank, which leads down to the railroad tracks and the Connecticut River, is eroding badly.
“VTrans is not happy with us already,” Pickup said of the state agency. The state owns the train tracks used by Vermont Rail Systems. He said about 800 feet of track was affected.
The strategy, according to Torizzo and Pickup, is to divert the stormwater runoff before it reaches the gullies.
While the Rockingham Select Board approved the grant application, board members also learned there would be a required 20 percent local match, which Pickup put at $265,000.
He’s working with the businesses in the industrial park that are affected by the runoff problem to help with the local share of the costs.
Later in the meeting, the board also agreed to spend $10,000 for immediate work on the erosion problem, installing heavy rock, or “rip-rap,” on some of the problem areas.
Torizzo said Northfield had installed a similar system to collect the water underground and divert it away from the gullies.
But he said the Spencer Drive location is “a lot more complicated.”
Pickup said the town is responsible, because when the industrial park was developed, the town maintained drainage rights.
Chroma is also doing work to stabilize the bank near its building on Imtec Lane. Torizzo said that Chroma is installing what he called a “plunge pool” to help collect stormwater, at a cost of about $100,000.
Torizzo told the board his design for the northern gully could withstand rain from a so-called 100-year flood, while the Spencer Drive gully solution is more limited, and probably could only handle a 50-year flood, or 4 inches of rain in a short period of time. A 100-year flood would be 5 inches, he said.
Select Board member Rick Cowan asked whether a 100-year flood would destroy the smaller system, and Torizzo said no, but it wouldn’t have that much of a mitigating effect.
All of the runoff is caused by impervious surfaces, such as roofs, parking lots and the roads, and according to Rockingham Select Board Chairman Peter Golec, the drainage coming from nearby Route 5 also is contributing to the problem.
Golec said drainage from Interstate 91 in the general location also caused a problem in the general vicinity of Leslie’s Restaurant, near the Exit 6 off-ramp, and the state came in and had to correct it.