Penn Brook Subwatershed Information
Municipalities: Boxford, Georgetown
Estimated Population: 2014
General Description: The Penn Brook subwatershed begins in Boxford at the watershed divide between the Parker River watershed and the Ipswich River watershed. A small stream flows behind the Spofford Pond School, around the Boxford sanitary landfill to Baldpate pond. Penn Brook then begins at the outlet of Baldpate Pond through wetland areas until it reaches Georgetown town center. It joins the Parker River downstream of Pentucket Pond. Flooding is a concern within the area of the subwatershed that is influenced by the Georgetown town center.
An anadromous fish run once existed in Penn Brook with alewives spawning in Baldpate Pond. Alewives can no longer reach Baldpate Pond due to impassable culverts at Central Street (Route 97) and at a rail bed easement further upstream. Boxford State Forest and Georgetown Rowley State Forest comprise some of the protected open space in this watershed, together with a few privately held protected parcels. The Undeveloped land use category has declined from 1905 acres in 1991 to 1793 acres in 1999. Residential land use increased from 567 acres in 1991 to 793 acres in 1999.
Acres/Square Miles: 2661 acres/4.2 square miles
Land Use as of 1999: Undeveloped – 1793 acres (67% of the subwatershed, Forest is 55%)
Residential: 793 acres (30% of the subwatershed)
Commercial/Industrial: 75 acres (3% of the subwatershed)
Named Tributaries: Bulford Brook
Lakes and Ponds: Little Baldpate, Baldpate Pond
Rapid Watershed Assessment: The proportion of impervious cover in this subwatershed is estimated to be 4.5%. The water quality would be expected to be of high quality. While a comprehensive survey has not been done, one would expect to find excellent habitat, diverse communities, and a stable stream channel. However, some localized impacts from summer low flows, road runoff, non-point source pollution and habitat alteration is likely. Impacts are expected
with future growth, predicted by recently completed development build-out analysis.
Water Quality Information: Monitoring conducted by the Department of Environmental Protection since 1975 indicates that Penn Brook is impacted by non-point source pollution. Monitoring was conducted at two stations on Bulford Brook and two stations on Penn Brook in 1978 as well as three stations on Penn Brook in 1994. Data from these stations indicate that Penn Brook suffers from low dissolved oxygen and relatively high concentrations of nutrients and fecal coliform bacteria.
A biological assessment was conducted in the vicinity of Parsonage Street in the summer of 1999. This survey, conducted in a 20-meter section of Penn Brook, revealed that the aquatic habitat in this area is severely impaired from habitat disturbance, while the macroinvertebrate survey indicates an absence of gross levels of organic pollution. Therefore, erosion, sedimentation, removal of riparian vegetation and localized sources of non-point source pollution are likely the
primary causes of the habitat impairment.
The Department of Environmental Management Lakes and Ponds Program conducted a survey of Baldpate Pond in 1998. The Department of Environmental Protection did a previous survey in 1981. There have been slight changes in water quality between the surveys, however land use change (from forest to low density residential) at the southern side of the pond will likely influence the future water quality. The Parker River Clean Water Association has a monitoring station located on Penn Brook at Georgetown High School as part of their monthly volunteer water quality monitoring program.
Recommendations: Continue to work with the Boxford Open Space Committee and Georgetown Open Space Committee to establish joint open space protection projects. Work with the Mass. Highway Department, Georgetown Highway Department and Massachusetts Electric to identify ways to eliminate obstructions to fish passage at Penn Brook. A shoreline survey and aquatic habitat survey should be conducted in this subwatershed. Outreach and volunteer efforts to address improper yard waste disposal, riparian buffer disturbance, non-point source pollution and littering of the stream is needed here.
Work with local groups to establish a link between Boxford State Forest and Georgetown-Rowley State Forest, possibly by establishing a protected greenway along Penn Brook. Need to locate, inventory and certify vernal pools.
(Data obtained from the Executive Office of Environmental Affairs, Massachusetts Watershed Initiative, 2002 Watershed Assessment Report)