US Bridges

Blackwater Road over Crystal Lake Brook

Fair

Grafton County, New Hampshire · 0.8 MI from Enfield Tl · Structure no. 003601000004000

Built
1988
37 years old, rebuilt 1992
Condition
Fair
inspected September 2024
Type
Culvert
Aluminum, Wrought Iron, or Cast Iron
Length
21 ft
1 main span
Daily traffic
550
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Blackwater Road over Crystal Lake Brook is a aluminum, wrought iron, or cast iron culvert carrying Blackwater Road over Crystal Lake Brook in Grafton County, New Hampshire. It was built in 1988 and reconstructed in 1992, so it is 37 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 fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 550 vehicles a day, roughly 4% of them trucks, projected to reach 814 by 2043. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesBlackwater Road
CrossesCrystal Lake Brook
Location0.8 MI from Enfield Tl
CountyGrafton County
StateNew Hampshire
Coordinates43.64687, -72.09965
Functional classUrban Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating74 US tons
Inventory rating49.1 US tons

Structure

Structure typeCulvert
MaterialAluminum, Wrought Iron, or Cast Iron
DeckNot applicable
Main spans1
Design loadUnknown
Structure length21 ft (6.4 m)
Longest span21 ft (6.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic550 (2023)
Projected traffic814 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
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 Blackwater Road over Crystal Lake Brook built?

It was built in 1988, making it 37 years old in 2025. It was reconstructed in 1992.

What condition is Blackwater Road over Crystal Lake Brook in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in September 2024.

How much traffic does Blackwater Road over Crystal Lake Brook carry?

About 550 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Blackwater Road over Crystal Lake Brook?

The structure is 21 ft (6.4 m) long with a longest span of 21 ft (6.4 m).

Who owns Blackwater Road over Crystal Lake Brook?

It is owned by the City or Municipal Highway Agency.