In a community meeting Thursday night, representatives laid out the possibilities for the future replacement of the Route 202 bridge over the Contoocook River.

The bridge is at the intersection of Route 202 and Route 136, between a major entrance to Monadnock Community Hospital and the town’s middle and high schools. It is in a deteriorating condition due to scouring from water, and is on the state’s Red List, meaning it must be inspected twice a year – rather than once every two years – to ensure it is still safe for travel.

The existing bridge was built in 1942, and widened in 1974. It underwent some mitigation procedures to address the scouring in 2019. The anticipated cost of replacement ranges between $10 million and $20 million, depending on the alternative chosen by the state.

The state will pay the cost of replacement, but Peterborough could be responsible for any costs associated with the relocation costs of a nearby sewer siphon or water line. Peterborough representatives who attended the meeting said the town’s preference would be an option that has the least impact on those lines.

Timothy Dunn, project manager for the New Hampshire Department of Transportation, led Thursday night’s hearing, and said it was an opportunity to lay out multiple possible avenues for addressing the bridge repairs or replacement, and to accept feedback from the public.

No official decisions have been made about which direction the project will take, Dunn said, but the state has determined that some options have more complications than others – although due to the small size of the lot and existing features such as an adjacent dam, sewer pipe and historical sites in the vicinity, there is no “perfect” option, Dunn said.

“There’s a lot of give and take everywhere,” Dunn said.

The first option, which Dunn said would not be the state’s preference, would be a rehabilitation of the bridge rather than a replacement. Dunn said rehabilitation might extend the life of the bridge, but would not address underlying issues with the scouring or the substructure, and the bridge would remain on the state’s Red List. It would have lower initial costs than replacing the bridge, but would only delay the need to eventually replace the bridge.

There are several options for replacement alternatives. The three main scenarios are to shift the bridge upstream, shift it downstream or replace it in its existing location – each option having several scenarios for how it could be accomplished.

Dunn said that in any of the scenarios, the state would commit to keeping pedestrian access in the area. Also almost inevitable for any of the scenarios would be the closure of Old Street Road where it connects with Route 202.

Upstream and downstream alternatives

The first option presented Thursday would be to build the bridge slightly upstream of its current configuration. It would allow the traffic flow to continue on the existing bridge, with the possibility of keeping two-lane traffic, and has the possibility of avoiding a sewer siphon downstream from the bridge.

Possible impacts from an upstream shift include the North Village dam, which is upstream from the bridge, and Rotary Park, which was formerly the location of the Wilder thermometer factory. It would require river access from both sides of the bridge.

The state has determined that a major upstream shift would not be possible due to the location of the dam, but a minor shift upstream may meet the needs of the project.

A downstream shift would also allow the state to maintain traffic on the bridge, and would avoid impacts to the dam and park, but would require modifications to the Route 136 and Old Street Road intersection. Changes would result in a sharper curve on Route 202, and would require the relocation of the sewer siphon downstream from the bridge, but could still meet the needs of the project.

In-place alternatives

Replacing the bridge in its current location is also an option, Dunn said, and there are several ways the state could do it.

The benefits of replacing the bridge in its current location are avoiding impacts to the sewer siphon and dam, along with the Route 136/Old Street Road intersection.

The first option, which Dunn said would be the least viable, would to be completely close the bridge and detour traffic using Route 136 through Route 31 – a significant detour that would move more truck traffic through Greenfield and Bennington and would require the construction of a pedestrian bridge over the Contoocook for the length of construction. It is one of the few options the state has determined wouldn’t meet the needs of the project.

The other options are phased construction and a temporary alternative bridge. The phasing option would reduce traffic to a single lane, and would extend the construction time over multiple years. Traffic delays are anticipated to be between two and four minutes during highest volume times for a single-lane bridge in the area.

The other alternative would be to use a temporary diversion bridge that would cause significantly less delay in traffic, but would have larger impacts to the canoe launch and a wetland parcel, and would require a larger entry point to accommodate truck traffic.

Ashley Saari can be reached at 603-924-7172, Ext. 244 or asaari@ledgertranscript.com. She’s on X @AshleySaariMLT.