I-66 Water Main Tunnel Rehabilitation

• Project scheduleStart Dates: Feb. 24 (N Nelson St side); March 10 (Hayes Park side)

Status

Construction

Location

The project limits are from the end of North Nelson Street toward Custis Trail to Hayes Park off North Lincoln Street. It is a steel liner plate tunnel that is 7 feet in diameter, 60 feet deep on the Hayes Park side and 35 feet deep on the North Nelson Street side.

Project Background

The tunnel was built at the same time as I-66 in the mid-1980s. The purpose of the tunnel is providing access to the critical 36-inch water transmission main in the event a repair is needed without digging up the interstate. The 36-inch water main was built at the same time as the tunnel and supplies water to the Clarendon and Virginia Square neighborhoods, as well as to the Gravity 2 and Gravity 3 pressure zones. The water main is elevated a few feet above the base of the tunnel.

The most recent inspection conducted in fall 2024 revealed that the entire tunnel was filled with groundwater, pointing to significant water infiltration in addition to corrosion. The rehabilitation work will involve using a cementitious liner/spray mixed with polymer to structurally repair the tunnel from within and seal any cracks that are causing leaks, therefore protecting the integrity of the 36-inch water transmission main. 

The 36-inch water transmission main will be taken out of service during the work; no impacts to water service are anticipated due to a redundant 36-inch water main nearby that can serve the demands for these areas. In addition, crews will be replacing any loose or missing bolts and joint restraints on the 36-inch transmission main while it is out of service during the tunnel rehabilitation work. 

Construction Impacts

Work began on Monday, Feb. 24, on the North Nelson Street side closest to Custis Trail and on Monday, March 10, on the Hayes Park side and will last approximately 3 months, weather permitting. Crews will work around the clock (including nights and weekends) for the duration of the project.

The rehabilitation work will require crews to concentrate on two access shafts: One located near Hidden Pond off North Nelson Street in the grassy area near the I-66 fence, and the second located near the basketball courts in Hayes Park. Below are the disruptions that can be expected from the work at both access shafts:

1. North Nelson Street Shaft Access:
   • No street parking from 17th Street North to the dead end of North Nelson Street.
   • No street parking on 17th Street North from the dead end to North Monroe Street.
   • The Custis Trail will remain open with limited temporary detours, and signage will be added to inform users of the work. There will be disruptions when equipment is being delivered across the trail (flaggers will be present to warn trail users).
   • A ramp will be set up on the trail near North Nelson Street (see map on back of letter).
   • Noise from large trucks delivering materials and equipment, and from the pumps and generators at the shaft location 24/7.
2. Hayes Park Shaft Access:
   • The basketball courts will be closed for the duration of the project.
   • No street parking on 15th Street North and part of North Lincoln Street.
   • Noise from large trucks delivering equipment and materials at 15th Street North, and from the pumps and generators at the shaft location 24/7.

 

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