Portions of Main Street in Gainesville will be closed beginning Monday for up to eight weeks as workers replace 100-year-old cast-iron water lines in advance of the city’s streetscape project slated to begin in June. Angela Sheppard, Gainesville assistant city manager, said Thursday both the northbound and southbound sides of Main Street at the intersection with Jesse Jewell Parkway will be closed beginning Monday as workers bore under Jesse Jewell Parkway. She estimated the boring would take about three weeks, after which the northbound side of Main Street is expected to reopen.