US Bridges

Silver Lake Road over Hydro Canal

Good

Belknap County, New Hampshire · .25 MI E of US Rte. 3 · Structure no. 025601330009400

Built
1984
41 years old
Condition
Good
inspected June 2024
Type
Frame
Concrete
Length
32 ft
2 main spans
Daily traffic
1,706
2023 count
Owner
State
State Highway Agency

About this bridge

Silver Lake Road over Hydro Canal is a concrete frame carrying Silver Lake Road over Hydro Canal in Belknap County, New Hampshire. It was built in 1984, so it is 41 years old, younger than the New Hampshire average of 56.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,706 vehicles a day, roughly 4% of them trucks, projected to reach 2,524 by 2043. The structure is 32 ft (9.8 m) long and 38 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesSilver Lake Road
CrossesHydro Canal
Location.25 MI E of US Rte. 3
CountyBelknap County
StateNew Hampshire
Coordinates43.472, -71.53381
Functional classUrban Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating36 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length32 ft (9.8 m)
Longest span15 ft (4.6 m)
Deck width38 ft (11.5 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,706 (2023)
Projected traffic2,524 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Silver Lake Road over Hydro Canal built?

It was built in 1984, making it 41 years old in 2025.

What condition is Silver Lake Road over Hydro Canal in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2024.

How much traffic does Silver Lake Road over Hydro Canal carry?

About 1,706 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Silver Lake Road over Hydro Canal?

The structure is 32 ft (9.8 m) long with a longest span of 15 ft (4.6 m) and a deck 38 ft wide.

Who owns Silver Lake Road over Hydro Canal?

It is owned by the State Highway Agency.