Land which had originally belonged to the dissolved townships and was still above water was redistrubuted to the towns bordering the Quabbin, including Belchertown.
The creation of the reservoir had also involved the creation of an extensive underground aquaduct to pipe the Quabbin's water east. The construction of the aquaduct entailed blasting an underground tunnel and sealing it with concrete, and was the most dangerous part of the project. The aquaduct is still periodically inspected for leaks and other damage.
More Info:
Quabbin Reservoir and Ware River
www.mwra.state.ma.us/04water/html/hist5.htm
Quabbin History Page
www.arps.org/pe/quabbin/History/historyindex.htm
Haunting the Quabbin: WBUR / NPR Special
http://www.insideout.org/documentaries/hauntingquabbin/default.asp
Reminiscing Over the Lost Towns of the Quabbin
http://stream.publicbroadcasting.net/production/mp3/wfcr/local-wfcr-532787.mp3
The Quabbin Reservoir: by the Fifth Grade at Pelham Elementary, 2004
http://www.arps.org/pe/quabbin/index.htm