Gainesville is gearing up to start the first phase of a multiyear, million-dollar-plus project to help with flood protection and restore water quality to a stream leading to troubled Flat Creek. The city is accepting bids on an effort to widen 800 feet of stream between Georgia and Hancock avenues and turn a pond that once was used for fire protection at the old Gainesville mill into a regional detention pond. “We’ve already drained it down, but we’ll be increasing the depth of (the pond),” said Horace Gee, the city’s environmental services administrator.