Bi-County Water Tunnel Reaches Milestone

Tunnel Boring Machine “Holes Through” at Tuckerman Shaft

	The cutting heads on the TBM can be seen from the Tuckerman Road shaft as they break through the shaft wall 135 feet  underground. LAUREL - (April 30, 2013):  Hitting a target 4.5 miles away when boring a tunnel 200 feet underground is quite a feat. Last Friday, the Tunnel Boring Machine (TBM) hit the target just a few feet off dead center, breaking through the wall of a shaft near Tuckerman Lane and I-270. Miners call it, “holing through.”  This was the last leg of the 5.3-mile tunnel and completes the mining portion of the Bi-County Water Tunnel Project. Pipe installation will begin after the TBM is lifted out of the shaft.   The tunnel, which runs approximately 200 feet underground along I-270 and I-495, will house an 84-inch diameter water main. When completed in 2014, the transmission main will connect two existing 96-inch mains and have a capacity of 100 million gallons of water per day. The new line is being constructed to respond to increasing demands for water in Prince George’s and Montgomery counties, as well as increase reserves in case of emergency. Check out the video of “hole through.”
	Established in 1918, today WSSC is among the largest water and wastewater utilities in the nation, with a network of nearly 5,600 miles of fresh water pipeline and more than 5,400 miles of sewer pipeline. Serving 1.8 million residents in Prince George’s and Montgomery counties, WSSC drinking water has always met or exceeded federal standards.