Concord River: Bradford Industries to Merrimack River Professional Review and Guide
"This run epitomizes urban paddling and is the closest class III–IV whitewater to Boston. The river is ledgy, with lots of man-made debris and a nasty breached dam at the end. There are three distinct rapids in the mile-and-a-half-long section. The scenery is nothing to write home about, although there are some interesting industrial artifacts along the route, including household appliances, shopping carts, and the occasional discarded tire. There have been a few reported incidents with the locals, including an encounter with a gang of rock-throwing teenagers who were repelled by brandishing a paddle, and a near miss from a juice bottle thrown casually off a bridge as boaters were passing beneath.
Since the run is short and the setting somewhat blighted, it’s not likely you’d choose the Concord as a weekend paddling destination, but if you find yourself passing through with a boat, or live around Boston and are sick of the tidal rip at Cohasset, check out the Concord for a little variety. The rapids generally have well-defined features. A couple of interesting surfing holes and waves form at higher water levels."