Northeast Boundary Tunnel Project Photo Gallery


Thank you, Chris the TBM!
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Check out our highlight reel! Below are photos from the Northeast Boundary Tunnel Construction Sites. It's a view behind the mesh-covered fences. At each of the construction sites, we are building facilities to connect to the existing sewer system and to support the tunnel. Photos will be updated periodically to highlight the work we are doing at each site.
 

Quick Links to Photos

Mount Olivet Road NE Construction Site First Street Pumping Station Construction Site
W Street NE Construction Site T Street NW Construction Site
Rhode Island Avenue NE Construction Site Florida Avenue NW Construction Site
4th Street NE Construction Site R Street NW Construction Site

 

Mount Olivet Road NE Construction Site

There are two construction staging areas on Mount Olivet Road NE: Department of Public Works (DPW) parking lot on Mount Olivet Road; and the intersection of Mount Olivet Road and Capitol Avenue NE. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility that will include a diversion chamber, a 25-foot diameter drop shaft, and other structures to convey flow from the existing sewer to the tunnel.


The  diversion sewer under Mt. Oivet Road NE was formed by pushing in a single pipe length as the tunnel was excavated. This view shows the tunnel portal and jacking frame about to install a pipe length.
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The M-TBM  completed excavating the diversion sewer under Mt. Olivet Road between the two construction sites on October 19, 2021. The new sewer will connect the diversion chamber structure to the new tunnel. 
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A peek inside the operator's cabin where he drives the micro-tunnel boring machine (M-TBM). 
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W Street NE Construction Site

The W Street NE Construction Site is located on the Department of Public Works property south of W Street NE. DC Water will construct a ventilation control facility that will include a ventilation channel, a 45-foot diameter junction shaft, and other structures to regulate airflow throughout the tunnel system.


Placing crushed stone aggregate as part of constructing the drainage swale located north of the Ventilation Control Vault structure.
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Clearing and grading the ground in the area of the proposed bioretention area on Department of Public Works grounds.
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After a rain, preparing to pump dry the flooded excavated area of the Ventilation Control Facility. 
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Rhode Island Avenue NE Construction Site

The Rhode Island Avenue NE Construction Site is located on Rhode Island Avenue NE near the 8th Place intersection. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility which will include a diversion chamber, a 25-foot diameter drop shaft, and other structures to convey flow from the existing sewer to the tunnel.


Drilling holes for expanding grout injection that will cause cracks to radiate in a concrete adit bulkhead that did not meet design criteria and must be demolished and replaced.
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After the expansive grout has provided several large cracks in the concrete bulkhead wall, the backhoe and hoe ram finish the demolition.
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Completing formwork before pouring the concrete for the replacement adit bulkhead.
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4th Street NE Construction Site

At this site, construction will occur along 4th Street NE north of the Rhode Island Avenue NE intersection. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility that will include a diversion chamber, a 20-foot diameter drop shaft, and other structures to convey flow from the existing sewer to the tunnel. The 4th Street Diversion Facility is designed to convey a peak flow rate of 457.2 million gallons per day to the Tunnel System.


Inspecting the hydraulic structures that were constructed to drop the combined sewer flow down the shaft to the Northeast Boundary Tunnel level while removing entrained air to help assure the system performs efficiently.
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Refreshing the scrim signage on the construction fence at 4th Street NE to remind customers that businesses are still open during construction.
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Aerial view of 4th Street NE construction site which is scheduled to be one of the first NEBT sites to be restored.
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First Street Pumping Station Construction Site

The First Street Pumping Station Construction Site is located at the intersection of Thomas Street NW and First Street NW. The First Street Tunnel (FST) serves as a large storage tank for the Bloomingdale sewer system during large storm events. After the storm, the Pumping Station pumps the combined sewage out of the FST to the existing sewer system. Once the Northeast Boundary Tunnel (NEBT) is connected to the FST, the Pumping Station will be decommissioned and demolished. The NEBT will convey the combined sewage from the FST to the Blue Plains Wastewater Treatment Plant.


Using a nuclear densitometer to measure and confirm the proper density of mechanically compacted soil.
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Excavating safely within a trench box to inspect a watermain.
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Workers removing the temporary bypass pump that maintained sewer flow during construction at the First Street Pump Station.
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T Street NW Construction Site

The T Street NW Construction Site is located at the intersection of T Street NW and Rhode Island Avenue NW. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility which will include additional storm water inlets, a 15-foot diameter drop shaft, and other structures to convey surface runoff to the tunnel. The T Street Diversion Facility is designed to convey a peak flow rate of 116.1 million gallons per day to the Tunnel System.


To line the drop shaft with concrete, the crew prepare the formwork where the adit connects to the shaft. Formwork is the temporary mold into which concrete is poured.
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Removing secant piles to connect the approach channel to the drop shaft which diverts captured flow towards  the NEBT. 
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Completing the demolition of the temporary secant wall to allow the connection to the approach channel.
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Florida Avenue NW Construction Site

Construction at this site will occur along 3rd Street NW and Florida Avenue NW. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility that will include a diversion chamber, a 20-foot diameter drop shaft, and other structures to convey flow from the existing sewer to the tunnel. The Florida Avenue Diversion Facility is designed to convey a peak flow rate of 322.8 million gallons per day to the Tunnel System.


After completing a concrete pour to form the wall of  the diversion structure , the crew remove the temporary wall formwork.  Formwork is the temporary mold into which concrete is poured.
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Demolishing the temporary secant pile wall to connect the diversion sewer to the approach channel which will divert  the  sewer flow to the dropshaft. Secant piles were placed in the ground to offer support and stability during deep excavation work.
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Maintaining the temporary lane separation delineators and traffic stripes on Rhode Island Avenue NW.
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R Street NW Construction Site

The R Street NW Construction Site is located within the triangular park bounded by 6th Street NW, R Street NW, and Rhode Island Avenue NW. In order to relieve chronic sewer flooding, DC Water will construct a diversion facility which will include a diversion chamber, a 38-foot diameter drop shaft, and other structures to convey flow from the existing sewer to the tunnel. The R Street Diversion Facility is designed to convey a peak flow rate of 264 million gallons per day to the Tunnel System.


Ironworkers placing and tying the reinforcing steel before pouring concrete to form a base slab.
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Tying formwork to rebar before pouring a concrete wall. 
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Placing the concrete base at the diversion structure. The rebar mat is partially covered by concrete. Note the large flume pipe on the right that maintains sewer flow and the cross bracing to support the excavated area. 
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Northeast Boundary Tunnel Project: dcwater.com/NEBT