Mill River

Mill River waterfall.

The Mill River begins in Conway, MA as a cold, rocky, fast-flowing stream. When it reaches the bed of the former glacial Lake Hitchcock, its character changes dramatically. Its rocky bed is replaced with sands and silts, its flashy temperament has quieted as it winds through pasture and a large natural marsh. In its north Whately section the river runs fairly straight, with only shallow meanders, all of which are bordered by dense tangles of silky dogwood and black willow. When the Mill River reaches the area known as Whately Flats (North Street in Whately), it is still surprisingly small.

From here, the Mill River meanders east, where it forms the western boundary of the large and legendary Great Swamp. South of the Great Swamp the river wiggles back and forth, forming relatively tight loops. In spite of its sinuousity, erosion along the well-vegetated banks is gradual, the exceptions being in those areas where yards or pasture form its borders.

South of the Great Swamp, the river continues meandering along the borders of farm fields and homes until entering an extensive shrub-swamp wetland below Claverack Road. Beyond this wetland, broad swamp forests form the river's borders until a pasture and the Whately wells are reached. The well site is one of the few areas on the river where erosion is extensive, and in 2000 and 2001, a short stretch of bank near the wells was stabilized to protect the safety of the wells. The stabilization effort was completed using a combination of riprap at the toe of the slope and soft engineering solutions, including coconut fiber rolls and natural vegetation.

Not far below the Whately wells the river is charged with the cold, clean waters of West Brook. Here, because of the construction of Interstate 91 in the 1960's, the Mill River follows the old bed of West Brook (some of the old meanders of the Mill River still exist on the east side of Route 91). For the next two miles, the river follows a straightened channel before abruptly resuming its original channel and passing through extensive red maple swamp forests. Near Bridge Road in Hatfield, the Mill River is joined by the last major tributary--Running Gutter Brook. At this point the river is also affected by the Hatfield Dam and backs up to form a large impoundment, characterized by extensive wetlands of water willow, silky dogwood and red maple.

The Hatfield Dam is located on a small outcrop of red sandstone, another small section of which is found near the Elm Street bridge in Hatfield. Below this point, the vegetation along the river changes to silver maple and cottonwoods.