Potential Mitigation Sites for Blue Hills Reservoir Project: Abandoned I9395 Interchange Stub in Can

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Potential Mitigation Sites for Blue Hills
Reservoir Project Abandoned I-93/95 Interchange
Stub in Canton and Ponkapoag Golf Course in
Canton Information provided by the
Massachusetts Wetlands Restoration Program (WRP)
11 February 2005

• This document is provided by the Massachusetts
  Wetlands Restoration Program to assist with the
  identification of potential mitigation sites for
  wetland impacts that would be caused by
  construction of the Blue Hills reservoir water
  supply project. All information herein is
  approximate only and intended for planning-level
  discussion of potential mitigation options. No
  field verification has been done to confirm the
  restoration potential of suggested sites, nor
  have owners or parties with interest in the sites
  been approached to discuss restoration.
• In 2001, WRP completed the Neponset River
  Watershed Wetlands Restoration Plan. The Plan
  identifies and characterizes 171 potential
  wetland restoration sites within the watershed.
  Several of these sites are located in the
  vicinity of the Blue Hills reservoir project.
  Two sites in particular are located within or
  directly adjacent to the Reservation and may
  offer practical compensatory mitigation options
  for the proposed wetland losses. Confirmation of
  restoration potential would require detailed site
  assessments and restoration feasibility studies.
• The two potential mitigation sites summarized in
  the following slides are the abandoned I-93/95
  interchange stub and the Ponkapoag golf course.
  Both sites are located in Canton and appear to
  contain large contiguous areas of historically
  altered wetlands on publicly-owned lands that are
  unencumbered by permanent uses (e.g., buildings
  or other permanent structures that would preclude
  restoration). Based on preliminary remote
  reconnaissance of these sites, WRP estimates that
  the I-93/95 interchange site offers very high
  ecological restoration value while the golf
  course site offers medium to high value.
• Other potential mitigation opportunities are
  located in the vicinity of the reservoir project
  and throughout the Neponset River watershed. The
  other sites within or abutting the Reservation
  are smaller wetland alterations and offer
  fragmented mitigation opportunities that are
  likely of lower value. However, should the two
  sites summarized herein be deemed not viable for
  mitigation, other sites within the Reservation
  and throughout the watershed could be
  investigated. WRP can provide limited further
  information on other opportunities if needed.
  Contact Hunt Durey, WRP Restoration Planner, with
  questions 617-626-1245 / hunt.durey_at_state.ma.us.

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Reservoir and Potential Mitigation Sites Location
Map
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Potential Mitigation Site for Blue Hills
Reservoir Project Abandoned I-93/95 Interchange
Stub in Canton

• Site consists of a portion of the abandoned
  I-93/95 interchange stub built in preparation for
  a direct highway connection to downtown Boston
  that was never constructed. The eastern portion
  of the interchange was built mostly within
  wetlands bordering the Neponset River (see 1941
  USGS map)
• Approximately 18 acres of historically filled
  wetlands could be restored via removal of fill
  down to historic wetland elevations without
  affecting existing MassHighway structures
• Potential benefits
• Very high ecological value for restoration large
  contiguous restoration opportunity of
  historically filled wetland located directly
  adjacent to Neponset River and part of Fowl
  Meadow wetland complex located within 100-year
  flood plain located within NHESP Estimated Rare
  Wetlands Wildlife Habitat and BioMap Core
  Habitat located within Fowl Meadow ACEC
• State-owned land (MassHighway) unencumbered by
  existing structures and with easy construction
  access
• Abuts Blue Hills Reservation and in close
  proximity to reservoir project
• Significant amounts of (presumed) quality fill on
  site that could potentially be used for
  construction of the reservoir project, and/or for
  other public or private projects to partially
  offset restoration costs
• Site is large enough to provide additional,
  future wetlands mitigation for other DCR /
  MassHighway projects
• Potential impediments
• Restoration would require relocation / removal of
  a significant amount of fill material
• State / MassHighway may have planned future uses
  for site

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Interchange Site 1980s USGS Map
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Interchange Site 1941 USGS Map
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Interchange Site Orthophoto
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Interchange Site Oblique Aerial Photo
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Potential Mitigation Site for Blue Hills
Reservoir Project Ponkapoag Golf Course in
Canton

• Site consists of several Ponkapoag Golf Course
  fairways, greens, cart paths, and other features
  that were constructed within historic wetlands
  (see 1941 USGS map) just downstream (southwest)
  of Ponkapoag Pond.
• Up to 36 acres of wetlands may have been altered
  by construction of the golf course through
  filling, ditching, draining, clearing, and other
  alterations restoration of a portion of this
  site could be achieved by relocating or
  eliminating one or more of the golf holes and
  restoring affected wetlands and appropriate
  hydrology
• Potential benefits
• Medium to high ecological value for restoration /
  mitigation large contiguous restoration
  opportunity of historically altered wetlands
  located downstream of Ponkapoag Pond and drains
  via Ponkapoag Brook to the Neponset River
  located within NHESP Estimated Rare Wetlands
  Wildlife Habitat and BioMap Core Habitat located
  within Ponkapoag Pond ACEC
• Located within Blue Hills Reservation and in
  close proximity to reservoir project
• Potential impediments
• Restoration would require relocation or
  elimination of one or more golf holes

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Golf Course Site 1980s USGS Map
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Golf Course Site 1941 USGS Map
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Golf Course Site Orthophoto
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Golf Course Site Oblique Aerial Photo