As the Assabet River winds its 31 miles through the watershed, over nine dams, and through the historic centers of old mill towns, its flow is joined by the waters of at least 16 named streams. Continuing downstream as the Concord River, another 4 named streams add their flow before the Concord joins the Merrimack River in Lowell. These small tributary streams, an almost unnoticed part of the landscape, are the hidden strength of the bigger rivers. Together they drain most of the watershed, comprise most of the miles of river/stream, provide much of the baseflow of the mainstem Assabet during the summer, and support the last remaining populations of riverine fish in the watershed.
For most of its first 17 years OARS concentrated on the mainstem of the Assabet River - for good reasons - but in 2002 we started to look upstream too. Of the many tributary streams to the watershed we decided to work on the largest streams in towns abutting the Assabet and Concord: River Meadow Brook in Chelmsford, Nashoba Brook in Acton, Elizabeth Brook in Stow, Danforth Brook in Hudson, North Brook in Berlin, Cold Harbor Brook in Northborough, Hop Brook in Shrewsbury, and the upper Assabet River just below the A1 Impoundment. Taken together these streams represent just over 70% of the drainage area of the basin and give us a picture of the overall health of the tributaries and, as we continue to explore them, each stream promises an interesting and different story.
In the following pages you can find descriptions of many of these tributary streams.