By Buck Fuller
Did you know the City recently spent $2.2 million to replace valves on the water main that runs under Little Bay? The four isolation valves for Portsmouth’s two, 20-inch diameter water mains had become inoperable, due to inadequate maintenance.
The upkeep of these water mains is essential. In 2023, 80 percent of the City’s water came from two sources, the 600-acre Bellemy River reservoir in Madbury and the Madbury well field.
The water mains under Little Bay are responsible for the transmission of this water.
These pipes run for 3,000 feet below the bay, between Fox Point in Newington and Wagon Hill Farm in Durham. There are two valves on each of them, one at each end of Little Bay.
The Air Force installed the water mains in the late 1950s during the construction of the Pease Air Force Base. The USAF also built the reservoir and the well field in Madbury.
Readers may wonder how the new valves could be installed on the live water main under pressure, considering that the existing valves were inoperable, and could not be used to turn off the water.
The replacement valves were installed using an insertion valve technology, as explained in the video below:
Insta-Valve 250 Insertion Valve — Quick Installation (youtube.com)
The project plans and bid tabulation for this $2.2 million dollar project can be found in the links below.
StagingPlan-Newington (cityofportsmouth.com)
22-24Awarded.pdf (cityofportsmouth.com)
Routine maintenance, which involves the annual opening and closing of the valves, could have prolonged the life of the existing valves.
Source Featured Image: Expressewer.com
