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

Land Area: 12.6 sq miles
Primary Municipalities: Clinton, Lancaster, Sterling
Permanently Protected Land Area: 597 acres or 7.9%
Limited Protection Land Area (Chap. 61, etc.): 44 acres
River length: 5.1 miles
Dam: 1 in Clinton

% Imperviousness: 17%
Land Use: 67% forest, 11% residential, 8% ag/open land
# of MA NHESP Priority Sites: 1
# of discharge permits: 1 major NPDES, 3 minor NPDES
Most threatened waterbodies: South Nashua River and South Meadow Ponds
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: This subbasin1 lies in the communities of Clinton, Lancaster and Sterling with a very small part extending into Bolton. Located in the Southern New England Coastal Plains and Hills ecoregion2 of central Massachusetts, the South Nashua River flows into the North Nashua River at "Meeting of the Rivers" in Lancaster from which point it is called the Mainstem Nashua River. The South Nashua River officially begins at the outfall of Wachusett Reservoir dam (which is the source of Lancaster Millpond). It flows north through the towns of Clinton and Lancaster. Routes 62 and 110 travel through this subbasin. Several freight train lines cross this subbasin.

Streamflow, as in most of New England, has significant seasonal changes3. It is interesting to note that this subbasin is unusual in having once been the site of a glacial lake (Lake Nashua) that flowed southward toward the Worcester area. At the end of the last Ice Age, its direction reversed, creating the Nashua River as we know it today. The South Nashua (and the Mainstem) River now flows northward from its impoundment at Wachusett Reservoir in contrast to all of the river's major tributaries, which flow in a southeasterly direction.

A very small portion of the Central Nashua River Valley Area of Critical Environmental Concern4 (ACEC) — currently the only ACEC in the Nashua River watershed —- falls within the northern section of this subbasin in the Five Corners neighborhood of South Lancaster.

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Land Ownership and Land Use5 Patterns: The land-use pattern is 67% forest (hardwood mixed with softwood) or wetland. Low-density residential settlement as well as concentrated settlements and strip development located near town centers and along major roads account for a total of 11% residential. Approximately 8% of total land area is agriculture and/or open land. Although these land-use estimates do not suggest a high risk for potentially contaminated runoff, the land-use along the South Nashua River in Clinton is primarily high density residential, industrial, and commercial. Such land use types have a much greater potential to negatively impact water quality due to urban runoff/storm sewers.

Indeed, 17% of this subbasin is total impervious surfaces6 —- namely, paved areas such as streets, driveways, and parking lots —- which indicates that issues of compromised stormwater and other non-point sources of contaminants (for example: pesticides, fertilizers, oils, asphalt, pet wastes, salt, sediment, litter and other debris) are a pressing concern. Primary pollutants of concern in stormwater are suspended solids, nutrients, metals, oil and grease, temperature and bacteria. The sources of bacteria in urban settings —- typically human litter and animal waste —- originate on driveways, lawns, commercial and residential streets, parking lots and rooftops. Furthermore, increasing urbanization leads to diminished groundwater recharge and to declining stream flow as well as stream channel widening and downcutting.

A shoreline survey of the South Nashua River within Clinton was conducted by the Clinton Stream Team in fall of 1999. Although several problems were noted —- including evidence of urban run-off, erosion (dirt bikes), severe sediment deposition, storm drains, trash and considerable debris —- the river was generally described as having a good buffer and was "aesthetically pleasing" in its upper reaches.

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Major Water Resource Issues: The South Nashua River is considered a warm water fishery. The flow of the South Nashua River is regulated by the operations of the Metropolitan District Commission dam at Wachusett Reservoir where hypolimnetic (very deep and cold, nutrient poor) water is released at a minimum rate of only 2.6 cubic feet per second. This small amount7 is perhaps not adequate to maintain natural flow regimes.

Major waterbodies in this subbasin are: in Sterling, East Waushacum Lake and Fitch Pond; in Clinton, Lancaster Millpond and the complex of Coachlace, Mossy, East South Meadow, and West South Meadow Lakes. South Meadow Ponds are classified as eutrophic and as having noxious plants and high turbidity. There is a large wetland at the inlet of Fitch Pond, which is hydrologically connected to the South Meadow Lakes complex via South Meadow Brook. Goodrich Brook is a feeder stream to the South Nashua entering that river upstream of the Clinton Wastewater Treatment Facility (WWTF). The only other contributing waterway is Counterpane Brook, which is underground in sections and otherwise channelized where it sees daylight.

The one major municipal effluent NPDES* permit in the subbasin is for the Clinton WWTF8 . Four additional NPDES minor industrial discharge permitees are: The Kelly Co., Inc. (discharging to Counterpane brook); Rockbestos Surprenant and Cable Co. (discharging to Rigby Brook); and Cumberland Farms/Gulf Gas and Weetabix Co.9 (both discharging to the South Nashua River). There are no registered water withdrawals permits.

The Nashua River Watershed Association (NRWA) collected fecal coliform bacteria samples in 1996 and 1997 in the South Nashua River. NRWA's data indicated elevated levels of fecal coliform bacteria during wet and dry weather conditions as did state Division of Watershed Management (DWM) water quality testing data. Based on the elevated fecal coliform bacteria counts, detection of unknown toxicity and best professional judgment, the indicator "Primary Contact Recreational Use" in the 1.6 mile reach of the South Nashua River downstream from the Clinton WWTF discharge is assessed as non-supporting; everywhere else recreational uses were assessed as partially supporting. "Secondary Contact Recreational Use" is assessed as partial support.

The state DWM water quality testing determined that there was moderate impairment to the benthic macroinvertebrate community as well as effluent toxicity, low dissolved oxygen, and high phosphorus, and thus assessed the indicator "Aquatic Life Use" as non-supporting. Further, elevated levels of phosphorus were detected in the Clinton WWTF effluent by the Environmental Protection Agency (EPA). Indeed, the sampling station located downstream of the Clinton WWTF had both the highest total phosphorus (TP) and ammonia-nitrogen concentrations of those surveyed in 1998 by DWM in the entire Nashua River Basin.

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Recreation and Priority Habitat Areas: Other than several town parks and recreation areas in Clinton, there is relatively little permanently protected open space in this subbasin other than Metropolitan District Commission lands immediately around Wachusett Reservoir. One other significant state holding is MassWildlife's Clinton Bluffs along the banks of the South Nashua River, which is also this subbasin's one state-designated Natural Heritage and Endangered Species Project (MA NHESP) Priority Habitat Area. This area is also designated a BioMap10 core area (as are two other small areas in Lancaster). There are no MA NHESP Rare Wetlands Wildlife sites within this subbasin. One habitat protection focus area identified in the Nashua River Habitat Assessment Report (MAS, 2000) is Wachusett Reservoir, which encompasses the South Meadow Ponds complex north of the reservoir. As a result, habitat conservation priorities should include protection of the South Meadow Brook area.

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Resource Protection Goals and Recommended Actions

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

  • Land protection efforts to focus undeveloped lands in South Nashua River floodplain (notably opposite Clinton WWTF and opposite Savage Field).
  • Sponsor local events to raise public understanding about native wildlife and the impacts of development patterns on ecosystem and habitat integrity.
  • Work with local conservation commissions to gain their backing of natural resource and habitat inventories.

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

  • Protect view from Woodruff Road overlooking river.
  • Encourage the use of MA Executive Order 418* funding for Open Space and Resource Protection Plans for each Massachusetts community in this subbasin.
  • Conduct public education sessions to promote local passage of Community Preservation Act*.
  • Work toward ideal of at least 25-50% protected open space in each municipality. Determine which Chapter 61, 61A and 61B properties to pursue Right of First Refusal* options on if the opportunity arises.
  • 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.

GOAL: Increase recreational opportunities throughout the subbasin.

  • Re-examine the feasibility of developing a multi-purpose trail along the railroad spur that extends from Water Street to the Hopfman property and Clinton Prairie Bluff area.
  • Organize and conduct "clean-up" effort of illegal dump site by Fuller Field on slope to Counterpane Brook as well as of the entire South Nashua River utilizing, in part, local citizen monitoring groups.
  • Support the South Meadow Pond and Nature Association in its environmental remediation efforts as well as survey and control invasive plant infestation (spread of noxious aquatics) in South Meadow Ponds.
  • Consider reclassifying the upper reach of the river to Wachusett Dam as a Cold Water Fishery given that it receives hypolimnetic release from Wachusett Reservoir during the critical summer months.
  • 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.

  • Identify sources of fecal coliform and other contaminants.
  • Evaluate the current minimum release from MDC at the Wachusett Reservoir dam. To the extent possible, maximize flow from Wachusett Dam to maintain natural flow regimes.
  • Determine locations of combined sewer overflows (CSOs) in Clinton. Continue to track progress of CSO abatement activities. Conduct additional dry and wet weather fecal coliform bacteria monitoring in most impacted segments of South Nashua River to identify potential sources of pathogens and other contaminants.
  • Identify and rectify problems with factory floor drains that may still discharge pollutants to waterways (versus to discharging to tight tanks or sewer systems).
  • Evaluate the need for stormwater controls (i.e., permits, pollution prevention plans, best management practices BMPs) in the industrial and commercial developments. Inventory, monitor and improve stormwater drainage structures.
  • Implement recommended BMPs from TMDL-urban runoff.
  • Identify any other WMA withdrawals in the subwatershed of this segment of the Nashua River. Evaluate any potential impacts of WMA withdrawals on streamflow/habitat.
  • If the Clinton Wastewater Treatment Facility continues to have problems meeting its whole effluent CNOEC (chronic no observed effect concentration) limit, a toxicity identification and reduction evaluation (TIE/TRE)* should be conducted.
  • Continue to monitor nutrient concentrations in most impacted segments of the South Nashua River and evaluate the NPDES facilities —- in particular the Clinton WWTF —- compliance with their effluent total phosphorous (TP)* limits.
  • Determine and rectify causes of sediment deposition.
  • Identify underground storage tanks (USTs) and work to have them removed.

GOAL: Reduce potential negative effects of some development in this subbasin.

  • Reduce total impervious cover to below 15% threshold.
  • 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 Collaborative11 workshop offerings).
  • Increase or establish staff hours for 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 For this Plan, subbasins were delineated and analyzed using USGS defined boundaries which sometimes are truncated at the gaging station and may not appear to be consistent with topographically determined drainage areas.

2 The Coastal Plains and Hills ecoregion is an area with generally similar soils, vegetation, shape of the land, cool climate and bedrock geology (glacial tills and outwash deposits). The Commonwealth of Massachusetts considers this physiographic region the "Central Upland" region.

3 Corresponding to seasonal stream flow changes are notable spikes in bacteria levels during summer and fall. Seasonal cycles of high bacteria concentrations may be attributed to decreased dilution during summer months, when tributary flows are lowest. (Wachusett Reservoir Watershed Protection Plan Update 1998, pp. 2-29)

4 ACEC url:

5 "Land Use" description at

6 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.

7 The overwhelming majority of the water is shunted off for metro-Boston's public water supply. In fact, the MDC/MWRA is registered to withdraw 126 Million gallons per day of surface water from the Wachusett Reservoir system.

8 The Clinton WWTF is under a sewer use moratorium for no increase in flow. The town of Clinton and the Lancaster Sewer District are co-permittees as the service area includes portions of Lancaster, which are under considerable growth pressure. The facility's permitted average monthly flow is 3 MGD.

9 Note that Weetabix's has a general non-contact cooling water permit and a closed loop system which only discharges to the river if this system fails.

10 BioMap url:

11 Citizen Planner Training Collaborative (CPTC) url
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