EDITED - I just realized it's not quite open yet. Another great park is in Southbury (probably about 20 minutes from Bristol) - No website, but here's some info:
Southbury Off-Leash Area
chairs, stream, poop bags. Park is fenced in on three sides. Back of the park has a river for swimming for dogs. Basket with toys for the dogs in center of field. Benches throughout the riverside. Table and Chairs in the center of the field. Driving Directions: 84 to exit 15. Take right off exit, third light (Rt. 67) take left. About a half mile down, turn right into O&G Industries. Park is on right, about a hundred yards down.