The New Hampshire Department of Transportation has formal approval for the complete replacement of two major state highway bridges in Andover. They are the Route 11 bridge near Dyer’s Crossing in East Andover, and the Route 4 bridge over the Blackwater River near the Andover/Salisbury town line. The November 7 meeting between the Bridge Commissioners and DOT officials was a formal “Finding of Necessity,” in which responses to public concerns about bridge plans and project implementation (expressed at the public hearings held at AE/MS last summer in June and July) were reviewed. There were a variety of concerns expressed, including compensation to abutting property owners for loss of land as the highway rights-of-way (ROW) will be widened and relocated, loss of income to maple sugaring operations on the abutting properties, changes to land access from the highway for agricultural
purposes, impacts to the environment and to historical features, and the temporary, but significant, inconvenience due to detours and closures during a short portion of the year-long projects. NHDOT engineers, ROW officials (who negotiate compensation for lost property), and NHDES representatives outlined their plans to lessen or mitigate these concerns, but allowed that some of these
cannot be totally avoided.
The “Finding of Necessity” is a formal green light for state highway projects. It is a required step before the project is put out for bid, and NHDOT applies for federal highway grant money, which incidentally will cover 100% of project costs as part of the recently passed federal infrastructure bill. Both bridges are greatly improved designs compared to the Depression-era bridges they will replace. The old bridges were originally designed for 100-years of service life, but have been “red-listed” by NHDOT a few years short of that mark due to deterioration and safety issues. The old-time engineers weren’t so far off the mark, however. Back then, Model A’s weighed only half as much as a typical car on the road today, and on a dare, they could only reach 60mph down a long hill! The old designers couldn’t have foreseen today’s high traffic volume  (about twenty thousand vehicles a day drive over the Route 11 bridge), faster
average speeds, and increased weight of modern vehicles compared to 1920’s cars and trucks. Modern traffic has only increased our need for bigger, better, and safer bridges. The Route 11 bridge demonstrates just how much civil engineering technology
has improved since a hundred years ago. The new bridge will be a remarkably efficient 210 foot single-span, which will replace both the rusted, crumbling five span iron bridge over the Northern Rail Trail, as well as the concrete arch bridge a few yards from it, crossing Sucker Brook. In addition, the highway’s challenging “S-bend” will be largely straightened out, and proper banking and
crowning of the roadway will make travel much safer, especially in slippery conditions. Shoulders will be widened to allow safer margins for pedestrians and cyclists. Construction on this site should begin in summer 2025 andconclude in 2026, and the road will remain open, albeit with a single-lane traffic control light. The Route 4 bridge will also be much larger than the bridge it replaces. The
deck will be four to five feet higher above the river than the existing bridge to accommodate floodwaters, and it will be 104 feet long, compared to 70 feet of the existing bridge. There will be significant changes to both approaches to the bridge (nearly a quarter mile in total) to include guard rails, stormwater swales, and permanent drain water easements for catch basins. The bridge will be
widened to include five foot shoulders on both sides to provide safer margins for pedestrians and cyclists. NHDOT proposes a 28 day road closure with a 22 mile detour via state highways through Salisbury and West Franklin. The eventual contractor is responsible for arranging an area for staging construction materials and equipment. The dates for construction will become firm sometime
after a bid is accepted, but NHDOT anticipates that the construction period for the two bridges will overlap. The two bridge Commissions were chaired by Executive Councilor Cinde Warmington, and by Andover ZBA chair Jon Warzocha. Andover residents
Vicky Mishcon and Ken Wells served as additional commissioners.