(Greenfield, MA) The sanitary sewer overflow that emerged in Greenfield Monday, concluded at 8:15 p.m. almost 10 hours after it began, discharging nearly 500,000 gallons of untreated sewage and waste into the Green River. While the overflow does not impact drinking water, it is recommended to avoid contact with the Green and Deerfield Rivers in Greenfield and the Connecticut River in Deerfield, Montague, and Sunderland until Wednesday at 8:15 p.m.