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Subbasins - Squannacook
Geographic & Ecosystem Characteristics | Land Ownership & Land Use Patterns
Major Water Resource Issues | Recreation & Priority Habitat Areas
Resource Protection Goals & Recommended Actions

Land Area: 73 square miles or ~ 46,720 acres
Permanently Protected Land Area: 7,902 acres or 18%
Limited Protection Land Area (Chap. 61, etc.): 705 acres
River length: 15.9 miles
Dams: 5; 3 in Townsend, 2 in West Groton

% Imperviousness: 7.3%
# of NHESP* Priority Habitat Species: TBD
# of NPDES* discharge permits: 1 Major
Most threatened waterbodies: Harbor Mill Pond

Location within the Nashua River Watershed Water Resources Habitat Analysis
Open Space Water Resources Natural Heritage
Limited Protection Water Resources Recreation

Geographic Overview and Ecosystem Characteristics: Located in "fuzzy" zone encompassing parts of both the Upper Worcester Plateau and the Southern New England Coastal Plains and Hills ecoregions1 of north central Massachusetts and southern New Hampshire, this area drains southeasterly into the main stem of the Nashua River near Ayer, Massachusetts. The Massachusetts communities of Groton, Shirley, Ashby, Pepperell, and Townsend lie wholly or partially within the Squannacook Watershed, as do the New Hampshire communities of Greenville, New Ipswich, and Mason. The topography ranges from steep "upland plateau" in the north and western sections to more gently rolling, hilly terrain to generally flat "coastal plain" lowland river valleys.

Designated an Outstanding Resource Waters (ORW)*, the Squannacook River is a high-value riverine ecosystem with high aesthetic quality and great wildlife habitat. Further, the subbasin has the distinction of being the focus of the Squannacook-Nissitissit Rivers Sanctuary Act (MGL 132A:17) passed in 1975 and intended to protect the ORWs of these two river basins from degradation by new discharges of pollution. The basin is considered to be a net exporter of surface water.

Streamflow, as in most of New England, has significant seasonal changes. Its headwaters drain an area that is some of the most forested (79%), least developed (10% residential) in the watershed. This results in a cold, clean main stem river that is frequently cited as prime habitat for listed rare species and native brook trout in the upper reaches.

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Land Ownership and Land Use2 Patterns: Land-use patterns vary from low-density residential in the uplands to more concentrated settlement and strip developments in the valleys, including gravel extraction, commercial operations and industry. Much of the subbasin is undeveloped, containing large areas of privately owned open spaces and a significant percentage of permanently protected land (Willard Brook State Forest, Pearl Hill State Park, Townsend State Forest, and Squannacook Wildlife Management Area as well as municipal and private non-profit conservation land). A low percentage (less than 8%)3 of total impervious surfaces — namely, paved areas such as streets, driveways, and parking lots — for this whole subbasin indicates that issues of compromised stormwater and other non-point sources4 of contaminants (for example: pesticides, fertilizers, oils, asphalt, pet wastes, salt, sediment, litter and other debris) is not an immediate pressing concern. As the Squannacook watershed becomes increasingly developed, there will be more threat of water quality deterioration from risks associated with urbanization, including thermal pollution, over-fertilization of lawns, improper handling of hazardous wastes, septic system leachate, street runoff, and the like.

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Major Water Resource Issues: This sub-basin as a whole contains important headwaters and high quality groundwater that are under intense development pressure which poses a threat to the future quantity and quality of the resource. As for other issues and
areas warranting attention,
all three major impoundments along the Squannacook — Hollingsworth & Vose (H& V), Leatherboard, and Harbor Ponds — are excessively vegetated. Also, elevated phosphate levels in each have fostered cultural eutrophication* negatively impacting recreational opportunities (boating, fishing and swimming). According to the 1998 Nashua River Watershed Report Card, the Squannacook River between Harbor Pond and Hollingsworth & Vose is rated as on alert for chemistry and swimming and partially supportive of biology5 due to elevated temperature readings above those protective for a cold water fishery. Downstream of Harbor Pond there are increasing water quality problems due to high levels of fecal coliform, low dissolved oxygen, erosion leading to sedimentation, increasing siltation and noxious aquatic and invasive weeds in Harbor Pond itself. Bixby Reservoir and Coon Tree Pond are both in an eutrophic state and contain noxious plants.

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Recreation and Priority Habitat Areas: Important habitat areas in this subbasin include: Wrights Ponds, Willard Brook State Forest, the Throne, and Townsend State Forest, which supports headwater streams of the Squannacook River. Trapfalls, Locke, and Pearl Hill Brooks each support Native Eastern Brook Trout as well as stocked trout. Flat Pond Brook in Townsend which had native Eastern Brook Trout until very recently, has been noted by fisheries experts to be filling in with sediment. Bayberry Hill, Bixby, Mason, Pumpkin, Walker, and Witch Brooks in Townsend are all cold-water fisheries and, with the exception of Bayberry Hill Brook, are also stocked with trout. In particular, conservation of riverfront lands is highly important, as a riverine "greenway" acts as a vegetated buffer to protect water quality and wildlife habitat, to prevent flood damage, and to provide outstanding recreation opportunities.

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Resource Protection Goals and Recommended Actions

GOAL: Protect wildlife habitat and migration corridors in the subbasin.

  • Expand the Squannacook River Wildlife Management Area along Witch Brook and Ash Swamp and the Willard Brook and Townsend State Forests.
  • Sponsor local events to raise public understanding about native wildlife and the impacts of development patterns on habitat and ecosystem integrity.
  • Work with local conservation commissions to gain their backing of natural resource/ habitat inventories.

GOAL: Protect high-priority open space, vistas, and community character in the subbasin.

  • Encourage the use of MA Executive Order 418* funds to complete municipal Open Space and Recreation Plan and other more site specific resource protection plans for each Massachusetts community in the Squannacook subbasin.
  • Conduct public education sessions to promote local passage of Community Preservation Act*.
  • Work toward ideal of at least 25-33% protected open space in each municipality.
  • Work with municipal officials to develop subdivision standards that require proponents to devote at least 50% of land (not including already undevelopable wet or steep land) for open space conservation and encourage mixed-use development and cluster zoning by-right bylaws.
  • Develop strategy for protecting Fessender Hill, as well as the views from Barker Hill and West Meadow Roads.
  • Support efforts of the Squannassit Regional Reserve Initiative* (facilitated by the NRWA) and the Squannassit ACEC nomination which encompasses much of this subbasin.
  • Encourage municipalities to adopt and enforce "Scenic River Protection" type bylaws* (similar to Townsend's Squannacook River Protection bylaw).

GOAL: Increase recreational opportunities throughout the subbasin.

  • Re-examine the feasibility of developing a multi-purpose trail along the abandoned B&M railway parallel to the Squannacook River from Ayer through Townsend.
  • Improve canoeing, fishing, and swimming opportunities by removing weeds from water bodies.
  • Educate the public and municipal departments (especially Public Works Depts.) on efforts relating to invasive species identification and removal.

GOAL: Improve water quality in the subbasin.

  • Support source water protection efforts of local communities, land trusts, and water suppliers.
  • Implement Total Maximum Daily Load (TMDL) Action Plan for Harbor Pond when completed.
  • Fund and install maintainable silt/sediment trapping forebay in Squannacook River behind existing dams prior to its reaching Harbor Pond.
  • Extend the Squannacook-Nissitissit Sanctuary Act into the New Hampshire portion of the watershed.
  • Identify the major sources of phosphate inputs to the river and work with communities to address the problem.
  • Assist the Town of Groton in implementing EPA's Phase II stormwater requirements. This municipality will be required to obtain permits to reduce impacts to the receiving streams through the development of BMPs, elimination of cross-connections and significant public education. CSO controls and the development of a long-range control plan will be required.
  • Inventory, monitor and improve stormwater drainage structures.
  • Identify the degree of threat from potential faulty/ illicitly discharging septic systems, which may result in bacterial and nutrient contamination of nearby streams and groundwater.
  • Identify underground storage tanks (USTs) and work with communities to have them removed.

GOAL: Reduce negative effects of development in this subbasin.

  • Help local volunteer board members responsible for development and land-use rulemaking and enforcement get technical assistance and information regarding techniques to control/guide land use and development balanced with adequate resource protection (e.g., Citizens Planner Training Collaborative6 workshop offerings).
  • Monitor increased imperviousness, both direct and indirect riparian zone alterations, and uncontrolled runoff from construction sites to prevent increased stream temperature and sedimentation through macroinvertebrate sampling performed by volunteer stream team monitors.
  • Increase or establish staff hours of municipal conservation agents to more effectively monitor construction sites runoff and assist with the preparation of bylaws such as erosion-sedimentation controls.

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* See glossary.

1 Ecoregions are areas with generally similar climate, bedrock geology, soils, vegetation, and shape of the land. The Worcester Plateau (or Monadnock Upland) has granite and schist bedrock and is cooler than the more moderate Southern New England Coastal Plains and Hills ecoregion, which has glacial till and outwash deposits for bedrock. The Commonwealth of Massachusetts considers this physiographic region the "Central Upland" region.

2 "Land Use" description at

3 According to the Center for Watershed Protection's Rapid Watershed Assessment Handbook protocol, an area with less than 10% (8 - 12%) impervious surfaces is considered "partially threatened; less than 8% is considered "sensitive" or what one would say is a relatively pristine environment;" 12 - 20% is considered "threatened"; and more than 20% is considered "non-supporting" or urbanized. The figures cited in the narrative are based on NRW Estimated Impervious Cover by Sub-basin based on '85/'92 Land Use: MDC '98 Methods Estimate by Bruce Bayne and Jo Anne Carr of the EOEA Nashua River Watershed Team.

4 Non-point source pollution, also known as polluted runoff, is the single largest source of water pollution nationwide. Polluted runoff is the result of rain or melting snow carrying pollutants or sediments from the land to the water. Polluted runoff results in water pollution from land-disturbing activities like agriculture, forestry, mining and urban development.

5 In the terminology of the 1998 Nashua River Watershed Report Card (DEP), "alert" means there is some indication that water quality impairment may exist based on any given variable, but there is not enough data to determine such. The term "threatened" is used when the use is fully supported but may not support the use within two years because of adverse pollution trends or anticipated sources of pollution. "Partial support" means a minor impairment, violation or objectionable condition with impairment being neither frequent nor prolonged.

6 Citizen Planner Training Collaborative (CPTC) url:
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