Workers are preparing to dredge the Charles River Thursday in search of clues to what caused part of a water main to burst last weekend, cutting off clean water supply to two million residents of Greater Boston.
Crews were unable to start dredging Wednesday, as originally planned, because they first had to shore up the land along the river to ensure that it could support a crane.
State officials say finding all or part of the pipe collar that apparently broke off will provide key evidence to what caused the rupture.
Meanwhile, the Massachusetts Water Resources Authority will hold an emergency meeting Thursday to convene an independent panel to oversee that investigation.
"We need to get the basic answers first, of how did this happen," said Ian Bowles, the Energy and Environmental Affairs Secretary, who also chairs the MWRA.
The panel will be charged with figuring out who should pay for the catastrophic failure.
"We would like to find the accountable party and then have them pay for the cost of the repairs and some of the inconveniences," Bowles said.
The panel will also address whether other parts of the water system could be vulnerable.
Bowles says the state might try to speed up construction on a redundant, back-up water system.
This program aired on May 6, 2010. The audio for this program is not available.