The new park runs two miles along the river, with a cycle path, a playground and a small café near the old boathouse. Work started last spring and finished a month early.
Residents can book the picnic shelters online from next week. The council says more benches and lighting will be added over the winter.
Local businesses along the route expect more visitors at weekends, and the café plans to stay open late through the summer.
The park is open from 6am to 10pm every day. Dogs are welcome on leads, and the cycle path links up with the canal towpath at the eastern end.
The council will hold a public meeting next month about extending the path further west.