Stillwater River (Nashua River)
The Stillwater River is part of the Nashua River watershed. This river is part of the Massachusetts Water Resources Authority system that supplies drinking water to the greater Boston area.
The Stillwater River rises in Princeton, Massachusetts, the watershed generally known as the Upper Worcester Plateau, or the Monadnock Upland. This watershed tops at Wachusett Mountain, the highest feature in the area. Water flowing east from this high ground feeds the Nashua River Watershed, and water flowing west feeds the Ware River or the Millers River, both heading to the Connecticut River. The Stillwater flows 8.1 miles (13.0 km) through Princeton and Sterling before joining the Quinapoxet River at the Wachusett Reservoir in West Boylston to form the south branch of the Nashua River.
The Stillwater and Quinapoxet rivers are the two major tributaries to the Wachusett Reservoir, which serves as the primary source of water for 2.5 million consumers in 43 communities of central and eastern Massachusetts. The U.S. Geological Survey (USGS), in cooperation with the Massachusetts Department of Conservation and Recreation (DCR), operates stream-flow monitoring gages near the mouths of both rivers. This and other continuous monitoring serves to maintain the overall quality of water within the reservoir. The water of
these tributaries to the Wachusett Reservoir has been of high quality for decades.
Stillwater headwaters near Princeton
About 47% of the Stillwater sub-basin is permanently protected open space. The Massachusetts Water Resources Authority owns much of the land. The Town of Holden owns over 600 acres (2.4 km2) as the Trout Brook Conservation Area, and the Massachusetts Audubon Society owns several hundred acres in the Wachusett Meadow Wildlife Sanctuary in addition to other properties within this sub-basin.
The Massachusetts Water Resources Authority (MWRA) is a public authority in the Commonwealth of Massachusetts that provides wholesale drinking water and sewage services to certain municipalities and industrial users in the state, primarily in the Boston area.
The authority receives water from the Quabbin and Wachusett Reservoirs and the Ware River in central and western Massachusetts. For sewage, it operates an effluent tunnel in Boston Harbor for treated sewage as well as a treatment center on Deer Island at the mouth of the harbor, among other properties.
The MWRA was created in 1985 and assumed sewage and wastewater treatment functions from the former MDC (Metropolitan District Commission), now the DCR (Department of Conservation and Recreation), which still maintains the watershed lands.