After more than a month of futile searching, officials have recovered a small piece of the failed coupling that caused the catastrophic water-main break on May 1 in Weston.
The piece, an 11-by-12-inch sealing plate, was found Wednesday in Weston during grading work between the Charles River and the mammoth pipe that supplies water to much of Greater Boston.
The lightweight sealing plate is one of two such pieces that were used to secure the coupling around the 10-foot-diameter pipe. Ria Convery, a spokeswoman for the Massachusetts Water Resources Authority, said additional searching on Wednesday did not uncover other pieces of the 1,200-pound steel coupling.
The coupling is considered a critical piece of evidence in the investigation into the water break that deprived 2 million people of reliable drinking water for three days. During that time, residents in Boston and most of its surrounding suburbs were instructed to boil water before performing such routine tasks as cooking, washing dishes, and brushing their teeth.
The search, which has cost $137,000, has been suspended until next week, when the MWRA plans to bore into an excavation pit next to the pipe. Potential "hot spots" have been identified there, where the soft, sandy soil has made digging difficult and posed new, possible dangers for the pipe.
Contractors dug 20 feet into the ground and 3 feet under the pipe in their unsuccessful effort to find the coupling, which consists of two large pieces of metal that measure a combined 31 feet long.
The failure to locate the coupling has been a mystery. Nearby sections of the Charles River have been searched, tons of soil have been sifted, ground-penetrating radar used, and extensive excavation done around the repaired underground pipe.
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