State Dept. of Transportation officials have pledged to examine Newcastle’s failing Lynch Road concrete box culvert as part of their study of the evolution of Sherman Marsh.
Charles Hebson, a state hydrologist, said he would at least look at the culvert. “It is worth a check of the hydrology. I will look at it and talk to some people,” he said.
Hebson is the manager of Maine DOT’s Environmental Office’s Surface Water Resources Division. As such, he has been involved in Sherman Marsh since a dam underneath a Rt. 1 bridge failed during a significant storm in Oct. 2005, draining the former Sherman Lake.
DOT officials immediately brought in temporary fill to protect the bridge. Soon, they realized the flowing water was too strong for the temporary fill, so they opened a second channel for the tidal current.
Later, despite objections of some town officials and Sherman Lake property owners, they decided to let the former lake revert to a salt marsh.
Newcastle town administrator Ron Grenier asked Hebson to examine the culvert after an engineering consultant said the swift outflow of tidal waters scoured the fill under the lip of the culvert. Newcastle engineering consultant Steve Reynolds said this may be the reason the front section of the massive four-year-old culvert is tilting, pulling the structure apart. If the culvert fails, the road could be damaged.
Reynolds has urged to town to replace or repair the culvert. The estimated cost to repair or replace the culvert is about $150,000, Reynolds said.
Hebson said he could not say if the swift tidal flow had damaged the culvert, but said it is worth checking out.
Selectman Pat Hudson said she was hopeful that state officials would look into the problems of the culvert and the tide.
“They decided not to replace the dam, and they opened another channel to let more tide water in and out, so in a way they are responsible,” she said.
“We expected things to happen (when the environment changed). We are not surprised it came up and will work with Ron Grenier on it,” Hebson said.