The city of Montpelier was busy Thursday dealing with a number of water main breaks.On Nelson Avenue, crews were removing part of the road after a water main break on nearby Barre Street washed out some of the pavement.About half a mile away on Sibley Avenue, another pipe cracked.The city said aging infrastructure is to blame for all of the breaks."A lot of times when we flow hydrants, it sends a surge of pressure through the system and finds the brittlest pipe and causes it to break there. Over here on Sibley, we are replacing it. We’ve had several leaks just this summer, and we decided we needed to step up and do it immediately. And the leak this morning is just another example of why we need a new water main," said Ryan Graves, who works for the city of Montpelier.Water service has been restored to all affected areas.Boil-water notices have been issued for Sibley Avenue from College to Sabin streets, all of Nelson Street and 1, 3 and 5 Ridge St.