On one side of the Annisquam River Monday afternoon, a crane reeled in 30-foot metal sections of pipe into place.
On the other side, another crew fed almost 1,200 feet of blue, plastic PVC pipe into an opening. In the middle of the river, boats floated on by, experiencing no signs of construction.
But the city-hired contractors were set to complete their biggest feat in replacing an over 100-year-old water main, feeding a 20 inch water main into a hole drilled about 57 feet below sea level at its plateau and pulling the blue PVC pipe — short for polyvinyl chloride — out the other side.
“It’s like having baby, you’re nervous until you see all ten fingers and toes,” said City Environmental Engineer Larry Durkin. “We just want to see that blue pipe pop out the other side.”
The water main will serve some 70 percent of Gloucester’s residents, everyone on the island side, and should continue to carry water from Bond Hill to residents for at least 200 years, according to Durkin. It replaces the “beyond its useful life” Spooner Tunnel water main that runs parallel to Stacey Boulevard, Durkin said.
Pulling the pipe through was a continuous project that contractors estimated would last about seven hours.
The blue PVC pipe made up of 30-foot segments melted and fused into a nearly 1,200-foot length of tube, snaked slowly into the ground, Monday afternoon. But, before crews could even lay the pipe, an entire drilling process had ensued.
A series of metal rods — each wider than the last set, connected at flexible joints and led by a computerized foot — dug the carefully planned underground tunnel, beginning at the city’s water treatment plant on Essex Avenue, and breaking back through to the surface on Gloucester High School land, near the softball field.
“It’s a series of reamers that open that hole up,” said Michael Bertram, lead driller for the contractor, Directional Technologies, Inc., based in Wallingford, Conn.
Then, before reversing the last and widest set of reamers, crews attached the end of the PVC pipe, and threaded the piping through the hole as they removed the reamers.
The $2.5 million project requires only city conservation commission permits and allows the city to create the new waterway without disrupting the environment, or really impacting the river in any obvious way.
The technology for digging such a hole only became readily available about 20 years ago, and has really taken off in the past five years according to Nick Strater, the senior project manager at tunnel design company Brierley Associates, hired by the city. Oil drilling often utilizes the same technique, according to Strater.
“It’s a very cutting edge approach,” Strater said. “It’s a very progressive way to get utilities into the ground.”
As the project reaches completion, with a second pipe set to head underground by October, the crew vows to be out of the school parking lot by Sept. 1, in time for the Sept. 6 opening of Newell Stadium. Water should run through the pipes by mid-October, after the pipes are disinfected and pressure tested, at which point the Spooner Tunnel pipes will retire.
Marjorie Nesin can be reached at 978-283-7000, x3451, or at firstname.lastname@example.org.