What is a Watershed?
What is a Watershed?
A watershed is a geographic area of land in which all surface and groundwater flows downhill to a common point, such as a river, stream, pond, lake, wetland, or estuary.
Water from falling rain and melting snow generally drains into ditches, streams, wetlands, lakes, and coastal waters, or seeps into the ground. As water moves over the land it picks up sediment and dissolved materials and transports them to lakes, rivers, ponds, streams and coastal bays. Vegetation, leaf litter, fallen logs, and the naturally uneven terrain of forests and other natural areas slow down and filter runoff. Water flowing over parking lots and other developed areas speeds up and can pick up a variety of pollutants on route to water bodies.
Nashua River Watershed
The Nashua River watershed is situated in north central Massachusetts and southern New Hampshire. It encompasses approximately 538 square miles of land that drain into the Nashua River and its tributaries. Within that landscape are 32 towns and cities which range from urban areas that were once booming milltowns that are today seeing revitalization around their riverfronts to small villages that have the look and feel of early New England with their Commons and historic districts. Many of these communities are facing rapid growth with the expansion of the Boston metropolitan area. Each one is unique and special, but one fact they all share—they are 32 communities connected by water.
Public Domain: USGS
Our Waterways
The Nashua River runs for 56 miles from the western edge of the watershed in Fitchburg, MA, south to Lancaster (known as the North Nashua River). In Lancaster, the Nashua turns north to travel downstream to Nashua, NH (known as the Mainstem Nashua River) where it meets the Merrimack River, with the Merrimack flowing out to sea at Newburyport, MA.
The watershed can be divided into four major aggregate subwatersheds: North Nashua River, Wachusett Reservoir, Nashua River mainstem, and the Squannacook and Nissitissit Rivers watersheds.
North Nashua River Sub-basin (Massachusetts only)
The North Nashua begins at the confluence of the Whitman River and Flag Brook in west Fitchburg. Nine dams and flood control retaining walls dominate the North Nashua as it passes through the City of Fitchburg. The river receives discharges from both the East Fitchburg and Leominster Wastewater Treatment Plants, and stormwater runoff from the cities of Leominster and Fitchburg. The river flows through Leominster State Forest and agricultural fields before joining with the South Nashua River in Lancaster.
North Nashua River tributaries include: Fall Brook, Falulah/Baker Brook, Flag Brook, Monoosnoc Brook, Phillips Brook, Wekepeke Brook, and Whitman River.
Wachusett Reservoir Sub-basin (Massachusetts only)
Wachusett Reservoir and its tributaries in the southwestern portion of the Nashua River watershed are water supply sources for the Massachusetts Water Resources Authority (MWRA), the public water system in eastern Massachusetts that supplies drinking water to Boston and the metropolitan area. The reservoir is created by the Wachusett Dam in Clinton which was built in 1897. The Quinapoxet and Stillwater Rivers, both high quality water sources that flow into the reservoir, are popular cold water fisheries. The water exiting the dam forms the South Nashua River flowing north to meet the North Nashua River in Lancaster. The Clinton Wastewater Treatment Plant operated by the MWRA is located on the South Nashua River.
Wachusett Reservoir tributaries include: Ball Brook, Chaffins Brook, Connelly Brook, East Wachusett Brook, French Brook, Gates Brook, Houghton Brook, Justice Brook, Keyes Brook, Quinapoxet River, Rocky Brook, and Stillwater River.
Nashua River Mainstem Sub-basin (Massachusetts and New Hampshire)
The Nashua River Mainstem forms the core of the Bolton Flats Wildlife Management Area and the Oxbow National Wildlife Refuge in Lancaster, Bolton, and Harvard where it winds north through marshy areas and former agricultural fields. Pepperell Dam in east Pepperell forms Pepperell Pond, an impoundment on the river popular for trophy large mouth bass and duck hunting. The river flows north through Hollis and Nashua, New Hampshire where it joins the Merrimack River. The towns of Ayer and Pepperell have wastewater treatment plants discharging directly to the mainstem Nashua River. The Devens Wastewater Treatment Plant has a subsurface wastewater discharge.
Nashua River Mainstem tributaries include: Bowers Brook, Catacunemaug Brook, Flints Brook, James Brook, Mulpus Brook, Nissitissit River, Nonacoicus Brook, North Nashua River, South Nashua River, Squannacook River, Still River, Unkety Brook, and Varnum Brook.
Squannacook and Nissitissit Rivers Sub-basin
The Squannacook and Nissitissit Rivers both flow directly into the Nashua River Mainstem. The Squannacook River flows through Townsend and Shirley. Hollingsworth and Vose Company, a paper manufacturer, holds the only surface water discharge permit to the Squannacook River. The Nissitissit River flows south from Brookline, New Hampshire through Pepperell. Much of the land along both of these rivers is forested, and protected parcels include the Townsend State Forest, Squannacook River Wildlife Management Area, Nissitissit River State Wildlife Management Area. Both rivers are popular cold-water fisheries.
Squannacook River tributaries include: Lock Brook, Mason Brook, Pearl Hill Brook, Trap Falls Brook, Walker Brook, Willard Brook, and Witches Brook. Nissitissit River tributaries include: Beaver Brook, Gulf Brook, Lancey Brook, and Sucker Brook.