Sudbury-Hudson Transmission Reliability and Mass Central Rail Trail Project - Stow MA
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March 13, 2020
Ref: 12970.00/14424.00
Hudson Conservation Commission
78 Main Street
Hudson, MA 01749
Re: WDA Design Group Peer Review - Applicants' Response to Comments
Sudbury-Hudson Transmission Reliability and Mass Central Rail Trail Project
Dear Members of the Hudson Conservation Commission,
The Applicants, NSTAR d/b/a Eversource Energy (“Eversource”) and the Massachusetts Department of
Conservation and Recreation (“DCR”), are providing this response to comments received in a letter dated
March 11, 2020, from the Hudson Conservation Commission’s third-party reviewer, WDA Design Group
(“WDA”). This supplemental submission also includes additional information regarding the February 7,
2020, email that was submitted to the Commission, which stated that the Project meets the definition of
previously developed and degraded Riverfront Area (“RFA”), and the Project fully complies with the
performance standards for RFA at 310 CMR 10.53(5) for “redevelopment within previously developed
RFA.” In addition, portions of the regulatory compliance discussion for Bordering Land Subject to Flooding
(“BLSF”) and Isolated Land Subject to Flooding (“ILSF”) were revised to reflect the plan revisions that were
submitted to the Commission as a supplemental submission on February 7, 2020.
This supplemental submission includes the following:
Response to comments received from WDA in a letter dated March 11, 2020;
Revised Bordering Land Subject to Flooding (“BLSF”) information including:
› Revised Section 5.1.5.1 Summary of Impacts discussion;
Revised Isolated Land Subject to Flooding (“ILSF”) information including:
› Revised Section 5.1.2.1 Summary of Impacts discussion; and
› Revised ILSF Proposed Mitigation Measures;
Revised Riverfront Area (“RFA”) information including:
› Revised 5.1.6 Summary of Impacts discussion;
› Revised RFA Proposed Mitigation Measures;
› Revised RFA Regulatory Compliance Summary demonstrating that the Project complies with
the performance standards at 310 CMR 10.58(5);
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Revised plan sheets 1, 18-37, 74, 75, 80-83, and 84-102 from the NOI plans in Attachment B with a
cover sheet that is stamped and signed with a revision date;
Revised plan sheets 1, C-07-C-26, D-02, and D-08 from the NOI plan in Attachment B with a cover
sheet that is stamped and signed with a revision date; and
An electronic copy of all of the above including full revised sets of the plans provided in Attachments
B and C.
Below is a list of comments and questions issued by WDA with a written response to each.
NOI Plan Comments - Transmission Line along MBTA ROW
1. The 164 Sheet plan set as provided does not bear the seal or signature of a Professional
Engineer or Professional Land Surveyor. Sheet 1 is missing (possibly a cover sheet with stamp).
The plans are all dated "Jan 2020" in the title blocks. WDA recommends that final plan sets
have a final revision date (not just month and year) in the title block, or if a plan has no
changes as submitted, then "no change" noted in revision blocks or stamped and dated cover.
The Commission would reference final stamped and dated plans in an Order, and therefore will
require a clearly identified date(s) on those final plans.
A signed, stamped, and dated updated electronic version of the plans is being provided to the
Commission with this response to comments so it can be uploaded to the Commission’s website.
Based on a conversation with Hudson’s Conservation Agent Pam Helinek on March 11, 2020, full
sets of revised plans also will be submitted to the Commission once the plans are finalized and
the Commission is preparing to issue an Order of Conditions (“OOC”). The final plan sets will be
bound and will include a cover sheet that has a revision date with the month, date, and year and
is stamped and signed by a Professional Engineer.
2. It appears in areas where streams/bank are delineated those flag label callouts are shown on
the plans. Although the approved wetland and vernal pool boundary locations are shown, the
actual wetland or vernal pool flag label callouts are not. The final plans should have the
wetland and vernal pool flag labels shown.
The wetland and vernal pool flag labels have been added to the revised Construction Plan sheets
that are being submitted electronically to update the NOI plans that were originally included as
Attachments A and B in the submitted NOI.
3. The erosion control barrier north of Station 120+70 should be extended up the slope to
approximately Station 120+50.
The erosion control barrier has been extended to 120+50 as requested. Please see updated sheet
26 for the revised erosion control barrier location.
4. At Station 123+50 to 124+10 north side, the revised plan shows this callout as “275 SF
Disturbance to 100’ RFA,” while the original plan had this called out as “275 Permanent Impact
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to 100’ RFA.” The Supplemental Document provided by VHB on February 7, 2020, specifically
Table 12, Station 109+90 to 124+90 lists the 275 of alteration under the Temporary Impacts.
The document should reflect this 275 SF within the Permanent Impact column.
This area of impact is correctly called out on the revised plan as temporary. As discussed within
the February 7, 2020 supplemental submission, the only area of permanent impact associated
with the Project is the paved 10-foot-wide MCRT. All other areas of disturbance will be restored
upon completion of the Project and will continue to protect the interests of the MWPA.
5. Approximately 52,129 SF of alteration is proposed within the RFA between Stations 105+90 to
124+90 (plan Sheets 25-27), yet no restoration plantings aside from the "General Construction
Corridor Seed Mix" is called for (Plan Sheet 131, Schedule C). It appears that there are areas
along this stretch that could accept shrub and or tree plantings without potential impact to the
subsurface transmission line vault, or the 2' wide gravel shoulders. We would recommend that
the Applicants review this area and provide some additional plantings for work within this RFA
and show those changes on revised Plan Sheets submitted to the Commission.
The RFA between Stations 105+90 to 124+90 was evaluated to determine whether additional
woody restoration plantings would be appropriate. The Project Site within this area has been
reduced to the extent possible to minimize work within the RFA, including an 18-foot-wide
construction platform, and most of the limit of work within this area is limited to the construction
platform. There will be narrow spaces outside of the bike path shoulders and transmission line
duct bank (less than 2 feet) that will remain and will not be periodically mowed which, although
narrow, could possibly support limited woody species. In addition, three slightly wider areas were
identified throughout this RFA, which includes:
1) An area to the north of the construction platform from approximately Station 115+75 to
116+40 that is approximately 700 square feet.
2) Two areas to both the north and south of the proposed manhole at approximately Station
120+00 to 121+80. To the north, the area is approximately 1,370 square feet and to the south
the area is approximately 1,175 square feet.
3) An area to the south of the construction platform from approximately Station 123+20 to
124+40 that is approximately 850 square feet.
After consulting with a licensed Landscape Architect, it was determined that planting this area of
RFA is problematic for nursery-grown woody shrubs and trees. Where the slopes are 2:1 or
greater, we have experience low survival rates with planted stock on other projects. Much of the
RFA to be restored will be subject to periodic mowing, leaving only narrow strips (2 to 3 feet
wide) adjacent to the 19-foot-wide maintained corridor available for planting. Planting this area
would create linear rows of plants that the Commission has already expressed concern about.
However, a seed mix containing seeds of alternate-leaved dogwood (Cornus alternifolia),
arrowwood (Viburnum dentatum), nannyberry (Viburnum lentago), and hazelnut (Corylus
americana) is proposed to be applied to these areas which would encourage woody vegetation to
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grow. By starting the plants from seed, the woody plants will be randomly placed and it will allow
them to grow their root systems to adapt to the slopes, therefore ensuring a higher rate of
success.
6. There are no callouts on Plan Sheet 131 (Planting Schedule) for plantings within Riverfront
Areas, although some of the referenced Stations noted for crane mat restoration areas
(Schedule A; notably Stations 147+25 to 150+25) are located within RFA associated with Fort
Meadow Brook and the crane mat restoration there will occur within RFA. The Planting
Schedule should reflect any RFA areas that are to receive supplemental/restorative plantings
(shrubs/trees) beyond the noted seed mixes and beyond just crane mat footprints.
All plantings within Planting Schedule A: Crane Mat Restoration Areas on sheet 131 in the plans
that were included as Attachment B of the NOI are located within RFA and have stationing
associated with the species and numbers of proposed plantings. In Hudson, the planting schedule
proposes to plant 10 each of gray birch, red maple, serviceberry, black oak, common winterberry,
highbush blueberry, and silky dogwood from Station 147+75 to 148+50, which is entirely within
RFA and is located to the west of Fort Meadow Brook (“FMB). The planting schedule also
proposes to plant 10 gray birch, 10 red maple, 15 serviceberry, 15 black oak, and 10 each of
common winterberry, highbush blueberry, and silky dogwood from Station 149+00 to 150+25,
which is entirely within RFA that is located to the east of FMB.
In addition, as discussed within Comment 5, seeds for woody species are proposed within three
locations of RFA from Stations 115+75 to 116+40, 120+00 to 121+80, and 123+20 to 124+40.
This seed mix has been added to the planting schedules on sheet 131 in the NOI plans included
as Attachment B of the NOI and is noted as “Riverfront Area Restoration.”
7. WDA has requested that VHB submit two additional details to the Commission for review and
clarification, specifically on Plan Sheet 130 for the proposed crane mats near FMB. We have
requested that a typical cross section of the existing right of way (ROW) near FMB be added
showing the reference location of the adjacent bordering vegetated wetland, flood elevation
and water elevation. Secondly a cross section detail of the proposed crane mat showing detail
of the construction of the mat and materials as it relates to the existing ROW, wetlands, and
erosion controls to be utilized on or around the crane mats.
Additional details were added to the plan set as requested. A specific FMB “Typical Crane Mat
Restoration Cross-Section – Bridge 130” was added to sheet 130. This cross section used Station
148+00 as a representative area for the purposes of the detail. The bordering vegetated wetland
(“BVW”) and BLSF elevations were added onto the detail. However, there are no LUWW or Bank
impacts at FMB and there is no LUWW at Station 148+00, so water elevations were not added.
This detail only applies to FMB from Station 147+75 to 148+50 and Station 149+00 to 150+25.
In addition to the specific FMB crane mat restoration detail, two details were added to sheet 125
in the plans provided in Attachment B of the NOI. These details, “Conceptual Crane Mat Section
with Steel Sheeting” and “Conceptual Crane Mat Section without Steel Sheeting,” show
conceptual configurations for the construction of the crane mat locations. As indicated in Note 3
of both conceptual details, geotextile fabric will be installed underneath and around the crane
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mats as an erosion and sedimentation control measure. These details are intended as a
conceptual, visual representation only; the actual configuration of the crane mats will stay within
the identified limits of work and will be determined by the contractor.
8. On Plan Sheets 29-30 and 184-188, and as further detailed in VHB Supplemental Letter dated
February 7, 2020 (attachment A, Table 1 and attachment B, Table 8) in regards to work within
the BLSF, the calculations show that there is a net increase of flood storage of 435.50 cubic
yards between Stations 142+30 to 154+90. Based upon our review of the cross sections and
other information we agree with the calculations. Please note that the net gain of flood
storage along the ROW is accomplished by removing a portion of the existing top surface
grade, down to the final grade for the paved pathway. This elevation change will result in a net
gain of flood storage but will mean that portions of the final pathway would be inundated (up
to 1-1.2' depth) during 100- year flood events. This may not be a Commission issue, but more of
a safety concern. The Commission may inquire of the Applicants regarding signage that alerts
path users of potential flooding danger in those specific locations.
Limited portions of other bike paths managed by DCR are periodically subject to flooding similar
to this path. DCR does not have a policy to restrict access to the path during flooding conditions.
No signage is currently planned to be displayed regarding the potential for the path to flood.
Please note that there are railings proposed on the side of the path in these areas that could be
used by a path user who entered flooded conditions and needed support.
9. On Plan Sheets 27-28 and 180, and as further detailed in VHB Supplemental Letter dated
February 7, 2020 (attachment C, Table 10) in regards to work within the ILSF, the Table
indicates a total of 760 SF of temporary disturbance, yet on Sheet 180, the cross sections
indicate that the grade of the ROW will be cut down and resulting in a overtopping of the
proposed pathway from the ILSF elevation of 194.2' to the adjacent BLSF elevation of 192.3'. Is
this shown correctly and if the ILSF elevation is allowed to overtop the pathway and flow into
the BLSF, is there a flood increase potential? The Engineer may need to clarify this area and
flood calculations for the Commission.
The Federal Emergency Management Agency (“FEMA”) completes county wide hydrologic and
hydraulic studies in order to determine flood elevations from various storm events. These studies
are summarized in the FEMA Flood Insurance Studies (“FIS”) and Flood Insurance Rate Map
(“FIRM”). The FIS within the study area is the Middlesex County FIS No 25017CV001C, which is
dated revised July 6, 2016. This FIS includes a macro-scale study of the hydrology of the
rivers/stream studied including the Assabet River Branch No. 4, which is the flooding source for
the BLSF at the area in question with a Base Flood Elevation (“BFE”) of 192.3. The FIS reports that
the discharge-frequency data was defined using regional equations which relate basin
characteristics to stream flows for the 10, 2, and 1- percent annual chance flow. The 1-percent
chance flow as a result of the macro-scale study of the hydrology is used to determine the BFE of
192.3 of the Assabet River Branch No. 4.
Regional equations (used within this FIS) are a valuable tool in macro-scale hydrologic studies to
estimate peak flow rates within streams and rivers using basin characteristics (slope, drainage
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area, cover type, etc). In short, they provide a conservative estimate of peak flow rates to be used
in hydraulic modeling to determine flood elevations. Given that they are macro level conservative
estimates, the hydraulic modeling estimates would not be impacted by a very minor change
within the watershed and micro-level ponding area such as the proposed grade change along the
ILSF. Therefore, the conservative estimate of peak flows used in the FEMA FIS for the Assabet
River Branch No. 4 would not be impacted by the proposed Project because it is a minor change
to the overall macro-scale analysis and accordingly there would be no impact to the BFE of 192.3.
Furthermore, the FEMA flood zone in this area is Zone A, which is an area subject to the 1%
annual chance event based on approximate study methods. Because this area was delineated
using approximate methods, the Project team took a very conservative approach and used the
closest available upstream BFE of the Assabet River No. 4 of 192.3 which over 600-feet
upstream. Therefore, if this area was studied in detail, it would likely result in a reduced BFE to
account for the drop in flood elevation over the 600-foot stretch.
10. On Sheet 31, there appears a hatched area (cross hatch) near Station 165+55 to 168+00
indicating a "vernal pool" this appears to be an error on the plan. This does not show on prior
ORAD or current MCRT plans.
The cross hatch on sheet 31 indicates the Kane Perkins driveway easement, which is shown
because it crosses the MBTA ROW. In comparison to the vernal pools on sheet 41 (Vernal Pool 1),
sheet 42 (Vernal Pool 2), and sheet 43 (Vernal Pool 3), the cross hatch for the vernal pools is
smaller and aligns with the hatch in the legend.
11. On Sheet 25, Station 107+90, there is an existing 30" clay culvert that runs SE to NW under the
ROW conveying an unnamed perennial stream and connecting wetland 1 to Wetland 2. The
culvert is shown as to be retained. Since the culvert is proposed to be retained is there
documentation as to its age, current condition and future viability. The Commission should
request documentation from the Applicant and Engineer as to the status of the culvert and a
contingency plan in case of damage during construction.
The existing 30-inch clay culvert located beneath the railroad embankment at Station 107+90 was
evaluated by VHB Structural Engineers in March 2017. The culvert is inside of a stone box and did
not exhibit any visible structural inadequacies at the time of the inspection, aside from some
decay of the north stone headwall, which is not a concern for the Project and does not affect its
function. The proposed design provides for over 4 feet of cover between the estimated top of the
culvert and the bottom of the proposed duct bank; thus, no damage to the culvert is expected to
occur during construction. Furthermore, the headwalls of this culvert are approximately 15 feet
outside of the proposed limits of grading for the Project and are not anticipated to be impacted
by project activities. However, should any damage to the existing culvert occur during
construction, Eversource will install a new reinforced concrete pipe having the same dimensions,
shape, and inverts as the existing culvert.
12. On Sheet 35, Station 206+10, there is an existing 24" clay culvert that runs SW to NE under the
ROW conveying and unnamed intermittent stream and connecting wetland 10 to Wetland 11.
The culvert is shown as to be retained. Since the culvert is proposed to be retained is there
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documentation as to its age, current condition and future viability. The Commission should
request documentation from the Applicant and Engineer as to the status of the culvert and a
contingency plan in case of damage during construction.
The existing 24-inch clay culvert located beneath the railroad embankment at Station 206+10 was
evaluated by VHB Structural Engineers in March 2017. Visual inspection of the pipe indicated
cracking along the ends of the pipe, likely due to a tree on top of the northeast corner of the
pipe. The pipe was clear inside, with no apparent collapsing. Eversource has proposed to cut the
tree on top of the northeast corner of the pipe in an effort to avoid further cracking. The
proposed design will incorporate a 4’x1’ transmission line configuration in this location to provide
for approximately 1.25 feet of cover between the estimated top of the culvert and the bottom of
the proposed duct bank; thus, no damage to the culvert is expected to occur during construction.
Furthermore, the ends of this culvert are over 5 feet outside of the proposed limits of grading for
the Project and are not anticipated to be impacted by project activities. However, should any
damage to the existing culvert occur during construction, Eversource will install a new reinforced
concrete pipe having the same dimensions, shape, and inverts as the existing culvert.
13. The Commission should discuss with the Applicant regarding a weekly/biweekly site
inspection/construction monitoring report (aside from any required SWPPP/EPA NPDES
reporting}, or a schedule that is appropriate to the level of work. The report should note where
work is occurring, type of work, weather conditions, and if any erosion control or other issues
are identified and timeframes for repair or remediation. A point of contact/report preparer
should be identified to the Commission and the report could be emailed directly to the CC
Agent. The Commission could make this a Special Condition in the Order.
The Applicants will follow reporting requirements included in the Order of Conditions (“OOC”).
14. Wetland and other resource area flags as approved by the ORAD, or under a new Order should
be refreshed in the field prior to the start of construction (the Commission could condition this
to be just the flags directly adjacent to, or within 50' etc. of proposed work areas, instead of all
flags associated with the 4.7 mile route that may not be close to work areas).
All wetland resource area boundaries that were approved in the ORAD will be reflagged prior to
construction.
15. The Commission should discuss with the Applicants how and where refueling of construction
vehicles will occur and unless unfeasible for certain aspects, re-fueling should occur outside of
sensitive areas or buffer zones.
Except for the crane that will be used for reconstruction the FMB bridge, where feasible, refueling
will not be permitted within the inner 100-foot RFA or within 100 feet of BVW, and, if possible
outside of the outer 200-foot RFA. Preferred fueling operations are at paved road crossings, if
practical. In addition, the Draft Construction Spill Prevention Control and Countermeasures Plan
that was provided as Attachment K in the NOI identifies the extensive measures that will be in
place during construction.
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16. All erosion control measures from Phase 1 (Eversource) should remain and be maintained
accordingly until Phase II (DCR path paving) is complete and all areas fully stabilized. Erosion
controls should not be removed until stabilized areas are reviewed by the Commission or their
Agent and ECB's approved for removal. Although this is noted as a General Condition #18 in
the DEP Order of Conditions Form 5, the Commission could expand or further define the
erosion control conditions if they deem necessary and add that as a Special Condition in the
Order.
All erosion control measures will be installed prior to the start of any earthwork during Phase I.
Eversource will be responsible for monitoring and maintaining all erosion control measures until
DCR begins Phase II construction. Once Phase II construction begins, DCR will assume
responsibility for maintaining erosion control measures, which will remain in place until the
Project Site is stabilized. Removal of the erosion control measures will not occur until approval is
received from the Commission’s Agent, or in accordance with any Special Condition of the OoC.
NOI Plan Comments – Mass Central Rail Trail
1. This 31-sheet plan set as provided has the seal and signature of a Professional Engineer on the
cover sheet only. The date under the signature is January 2, 2020. The plans are all dated "Jan
2020" in the title blocks. WDA recommends that final plan sets have a final revision date in the
title block (not just month and year), or if a plan has no changes as submitted, then "no
change" noted in revision block or on stamped and dated cover sheet. The Commission would
reference final stamped and dated plans in an Order, and therefore will require a clearly
identified date(s) on those final plans.
Please see response to Comment 1 under NOI Plan Comments – Transmission Line along MBTA
ROW. The same update will be made for this plan set.
2. WDA received three revised sheets on February 7, 2020 from VHB for the MCRT plan set,
specifically sheets C- 01, C-03 and C-07. Sheet C-01 was updated to show the new wetland flag
BP-4A and updated wetland boundary and a revised callout for "612 SF of pavement and 983
SF of loam and seed in the 200' RFA". Sheets C-03 and C-07 were updated with callouts
referencing SF of pavement and loam and seed in the RFA and pavement and loam and seed in
BLSF respectively. These plans did not a have professional stamp or revision date.
Please see response to Comment 1 under NOI Plan Comments – Transmission Line along MBTA
ROW. The same update will be made for this plan set.
3. Sheet C-01 of the MCRT plans shows work located within both the 100' buffer zone and outer
200' RFA. Most of the work proposed here is located within previously disturbed or maintained
areas adjacent to the paved ARRT parking area and trailhead. Although there is work proposed
in the outer 200' RFA it is located as mentioned in disturbed areas and the existing paved
ARRT is located between the proposed work area and the actual perennial water body. The
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Applicant has shown adequate erosion control measures and proposed stabilization and
plantings in this area.
No response required.
4. Sheets C-04 and C-05 show planting symbols and species callouts for plantings in disturbed
ILSF areas. Sheet C-09 shows planting within disturbed buffer zone (adjacent to Wetland #9).
How were these locations determined for plantings, while other areas within RFA or adjacent
to vernal pools or other BVW's do not indicate any additional tree/shrub vegetation beside the
noted seed mix.
The AASHTO Guide for the Development of Bicycle Facilities states “depending on the height of
the embankment and the condition at the bottom, a physical barrier such as dense shrubbery,
railing or fencing may be needed.” Due to the steep slope and the elevation difference between
the top of the embankment and the bottom on sheets C-04, C-05, and C-09, a safety feature is
required. For aesthetic reasons, a landscaping option was chosen in these areas instead of fencing
or railing.
5. As noted previously in the review of the MBTA ROW Plans (comment #5), approximately
52,129 SF of alteration is proposed within the RFA between Stations 105+90 to 126+70, yet no
restoration plantings aside from the "General Construction Corridor Seed Mix" is called for
(Plan Sheet 131 of MBTA ROW Plans, Schedule C). It appears that there are areas along this
stretch that could accept shrub and or tree plantings without potential impact to the
subsurface utility vault, or the 2' wide gravel shoulders. We would recommend that the
Applicants review this area and provide additional plantings for work within the RFA and show
those changes on revised Plan Sheets. It should be clarified if plantings will be the
responsibility of DCR after paving in this area (Phase II) or Eversource following Phase I
completion, or a combination.
Please see response to Comment 5 under NOI Plan Comments – Transmission Line along MBTA
ROW. The shrub seed mix will be applied by Eversource following Phase I completion.
6. See comments #11 and #12 in MBTA ROW plan review section regarding clay cross culverts.
Please see response to Comment 11 under NOI Plan Comments – Transmission Line along MBTA
ROW.
7. See comment #13 in MBTA review.
Please see response to Comment 13 under NOI Plan Comments – Transmission Line along MBTA
ROW.
8. See comment #15 in MBTA review.
Please see response to Comment 15 under NOI Plan Comments – Transmission Line along MBTA
ROW.
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9. According to the NOI submittal materials, DCR will be responsible for invasive species
management as part of any on-going future path management. Is this to be a condition in
perpetuity?
DCR will manage invasive species for the lifetime of the MCRT.
10. All erosion control measures from Phase 1 (Eversource) should remain and be maintained
accordingly until Phase II (DCR path paving) is complete and all areas fully stabilized. Erosion
controls should not be removed until stabilized areas are reviewed by the Commission or their
Agent and ECB's approved for removal. Although this is noted as a General Condition, #18 in
the DEP Order of Conditions Form 5, the Commission could expand or further define the
erosion control conditions if they deem necessary and add that as a Special Condition in the
Order.
Please see response to Comment 16 under NOI Plan Comments – Transmission Line along MBTA
ROW.
NOI Plan Comments – Transmission Lines along Roadways
1. The Applicant's Engineer, VHB has submitted that the work associated with these plans are
exempt from WPA jurisdiction pursuant to 310 CMR 10.02(2)(b)1and 2. Specifically, 310 CMR
10.02(b)2.i. "that the installation of underground utilities within existing paved or unpaved
roadways within 100-foot Buffer Zone or Riverfront Area is exempt. Accordingly, impacts to
these resources are not included for the portion of the transmission line within existing public
roadways". We agree with this categorization as it meets the exemption as noted, and the
Applicant is proposing erosion control and stabilization measures as part of the work as
categorized in 310 CMR 10.02(b)1.
No response required.
2. Based upon our review of the work within the noted roadways proposed on these plans, it
appears that Sheets 4, 5, and 12-14 have work within the 100' buffer zone, and erosion control
barriers are shown protecting off-site adjacent resource areas. Sheets 16 and 17 would have work
within the 100' buffer zone to adjacent wetlands, although the buffer zone is not shown on these
two sheets. The buffer zone and adequate erosion controls should be shown on these two sheets
and revised, and dated sheets issued to the Commission.
As approved in the ORAD, the two wetlands on sheets 16 and 17 are isolated wetlands/potential
vernal pools and therefore do not have an associated 100’ buffer zone. However, erosion controls
are currently being added to the sheets as requested and will be provided to the Commission at a
later date.
3. Sheets 6-8 and 12-15 have work shown within Riverfront Area. The roadway utility work within
the RFA is exempt under 310 CMR 10.58(6)(b) which refers to the 310 CMR 10.02 (2)(b) 1 and 2
"minor activities". These sheets appear to have adequate erosion controls along perimeter work
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areas, but the Commission should ask the Applicant to clarify if "silt sacks" are being utilized in
catch basins which may have associated culvert discharge points within RFA or Buffer Zone areas.
Appropriate erosion and sedimentation controls will be used at catch basin to protect the
stormwater management system. Page 14 of the Best Management Practices (“BMPs”) included as
Attachment I with the submitted NOI discusses the use of catch basin protection, including filter
bags.
4. Please note that under the exemption provision for underground utilities that all trenches are
to be closed at the completion of the workday. The Commission could make that a Special
Condition in any future Order. All erosion control measures should remain and be maintained
accordingly until final paving is complete. Erosion controls should not be removed until areas
are reviewed by the Commission or their Agent and ECB's approved for removal.
All trenches for the underground transmission line will be closed at the completion of each
workday.
Wildlife Habitat Comments
1. If the Commission does not yet have a copy of the Corridor Management Plan and Box Turtle
Protection Plan, they should request one be submitted for their records and any future
reference.
Copies of the Draft Corridor Management Plan and Draft Eastern Box Turtle Protection Plan are
included for the Commission’s reference.
Engineering/Stormwater Management Comments
1. The engineer should review the Checklist for Stormwater Report. It appears some items may be
applicable for Stormwater Standards 3, 4, 5 and 9, but have not been checked. (completed)
The Checklist for Stormwater Report was revised and provides clarifications in red text.
2. There is a statement in the Stormwater Report (pg. 49) stating the check dams result in an
"effective" longitudinal slope of two percent in all swales. Is there a calculation or reference to
support this?
The check dams have been located within the swales (see Construction Plans Sheets 24-43) to
provide a minimum effective slope of 2% (the slope from the top of one check dam to the top of
the next check dam) where the longitudinal slope of the swale exceeds 2%. The spacing for a 6-
inch high check dam has been calculated to be 100 feet for slopes between 2% and 3%; 50 feet
for slopes between 3% and 4% and 30 feet for slopes between 4% and 5%. The swales have been
designed so that the longitudinal slope does not exceed 5%.
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3. The Stormwater Report Section 3 Regulatory Compliance, Standard 9: Operation and
Maintenance Plan references an Operation and Maintenance (O&M) Plan, but O&M Plan was
not provided for review.
An O&M Plan has been prepared and a pdf is included as an attachment to this supplemental
submission.
4. The plans indicate portions of the path will be flooded during the larger design storm events.
Is there a policy in place regarding access to the path when flooded? Will this policy be posted
along the path with signage or other means?
Please see response to Comment 8 under NOI Plan Comments – Transmission Line along MBTA
ROW.
5. Some of the HydroCAD output data says "TcHudson Conservation Commission
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5.1.5 Revised Land Subject to Flooding (310 CMR 10.57)
5.1.5.1 Revised Bordering Land Subject to Flooding
Summary of Impacts
The Project was designed to fully comply with all applicable performance standards for BLSF and
will result in a net gain of 433.5 cubic yards of flood storage.
As outlined in Tables 8 and 9, the Project will result in permanent and temporary impacts to BLSF
at two locations within the Project Locus. The first area (between Station 131+10 and 132+00) is
just west of Chestnut Street and is associated with an unnamed perennial tributary to the
Assabet River that is located north of the Project Locus. The second area (between Station
142+50 and 164+00) is east of Chestnut Street and is associated with Fort Meadow Brook. In all
cases, permanent disturbance is due to the paved surface proposed for the MCRT and temporary
disturbance includes all areas outside of the paved MCRT. All disturbed areas outside the limits
of the paved MCRT will be revegetated with native species once construction is complete.
impacts in both locations are due to paving the MCRT. Table 8 identifies the square footage of
impact in each area; Table 9 summarizes the changes to flood storage volume.
There is no BLSF along the MCRT Connection nor along the component of the Project within
public roadways.
5.1.5.2 Revised Isolated Land Subject to Flooding
Summary of Impacts
The Project was designed to fully comply with the applicable performance standards for ILSF.
There is one ILSF that is partially located within the Project Locus in Hudson and the Project will
result in 760 square feet of temporary impacts to ILSF due to grading (cut) and vegetation
removal (see Table 10 below). This ILSF is associated with a forested isolated wetland (Wetland
5); however, the ILSF impacts are upslope on the raised railroad embankment and will not impact
the wetland itself. There are no permanent impacts within ILSF associated with this Project.
Proposed Mitigation Measures
The Project will result in 760 square feet of temporary impacts to ILSF. However, impacts to the
ILSF are a cut, not a fill, and will result in an increase of 99.07 cubic yards of flood storage.
Therefore, mitigation for a loss in flood storage volume is not required. Once construction is
complete, all disturbed areas will be loamed and seeded with a native seed mix and a portion of
the ILSF will be planted with native shrubs as part of Phase 2 construction.
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5.1.6 Revised Riverfront Area (310 CMR 10.58)
Summary of Impacts
The Project was designed to fully comply with all applicable performance standards for RFA and
will provide an improvement to the previously degraded areas.
There are five locations of RFA within the Project Locus:
MCRT and Underground Transmission Line along the MBTA ROW
› Station 105+90 to 124+90: Associated with unnamed perennial stream east of Wilkins
Street
› Station 146+45 to 151+10: Associated with Fort Meadow Brook
MCRT Connection to the ARRT
› Station 10+20 to 10+80: Associated with an unnamed perennial tributary to the Assabet
River, north of the existing ARRT.
Underground Transmission Line within Public Roadways
› Station 18+40 to 26+70: Associated with an unnamed perennial stream south of Forest
Avenue, near the intersection with Marlboro Street.
› Station 50+00 to 60+40: Associated with an unnamed perennial stream currently
conveyed through a culvert beneath Forest Avenue, just west of Glendale Road.
Installation of underground transmission lines within existing paved roadways within RFA is
exempt pursuant to 310 CMR 10.02(2)(b)1. Accordingly, the amount of RFA within existing public
roadways is not included in the total RFA on the Project Locus and impacts are not included for
the portion of the transmission line that is within existing public roadways.
The existing RFA within the Project Locus in Hudson for the portion of the Project that is within
the MBTA ROW and the MCRT Connection to the ARRT is 219,261 square feet. As outlined in
Table 12, the Project will result in 23,558 square feet of permanent impacts to RFA (10.7 percent
of total RFA) from paving the MCRT. The Project will also result in 41,232 square feet of
temporary impacts to RFA (18.8 percent of total RFA) due to installation of the underground
transmission line, construction of the MCRT base, site grading, and the placement of crane mats
to accommodate reconstruction of Bridge 130 (Fort Meadow Brook bridge).
Proposed Restoration and Mitigation Measures
The Project was designed to avoid and minimize impacts to RFA to the extent practicable by:
Reducing the construction platform width to 18 feet from Station 112+87 to 120+75;
Using a retaining wall from Station 119+00 to 124+95 (at the Hudson and Stow municipal
border);
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Reducing the construction platform with to 18 feet from Station 146+66 to 174+85 and
from Station 150+15 to 151+10 (Fort Meadow Brook area);
Using steel sheeting at Fort Meadow Brook to minimize the limit of disturbance; and
Placing all but one manhole (at Station 120+75 to 121+25) outside of RFA.
In addition, the following restoration and mitigation measures will be implemented in RFA:
Erosion and sediment controls will be installed to protect the associated waterbodies.
Crane mats at Fort Meadow Brook will be in place for the minimum duration necessary and
will be removed immediately upon completion of activities where the use of a crane is
required.
Following removal of the crane mats, the area where mats were placed will be restored by
raking and re-grading the soil (if necessary due to soil compaction).
The crane mat area will be stabilized with jute mesh erosion control blankets and planted
with native herbaceous and woody plant species (see crane mat restoration detail and
planting schedule for the crane mat restoration areas on sheets 130 and 131 in the NOI
plans in Attachment B). The trees and shrubs will be planted after Phase 2 construction is
completed to avoid disturbing and/or damaging the plants. If necessary, the area will be
reseeded with an appropriate seed mix that will allow for the regrowth of indigenous, non-
invasive herbaceous species to supplement natural recruitment.
After Phase 1 is constructed, all disturbed areas outside of the 14-foot gravel base will be
loamed and seeded with the seed mix shown on sheet 131 in the NOI plans in Attachment
B.
After Phase 2 is completed, DCR will loam and seed the two-foot shoulders on either side of
the MCRT so that all permanently disturbed areas except for the 10-foot wide MCRT are
revegetated.
Once the Project is complete, all areas outside of the 19-foot-wide final maintained width
will be allowed to naturally revegetate with woody vegetation.
Regulatory Compliance Summary
As discussed in Section 5.1.1 above, both phases of the Project qualify as limited projects for
relief from certain provisions of 310 CMR 10.58 for work in RFA. In addition, because the RFA in
the Project Locus is previously developed from the former railroad ROW operations, including
degraded areas where the ballast, rail, and ties are located, the Project is a redevelopment
project that proposes reuse of degraded and previously developed areas subject to 310 CMR
10.58(5). The Project fully complies with all applicable performance standards at 310 CMR
10.58(5), which requires compliance with 310 CMR 10.58(4) and (b), but not (c) and (d).
As outlined below, the Project fully complies with the provisions of 310 CMR 10.58(4)(a) and (b):
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10.58(4)(a) The work shall meet the performance standards for all other resource areas within
Riverfront Area. When work in the RFA is also within the buffer zone to another
resource area, the performance standards for the RFA shall contribute to the protection
of the interests of M.G.L. c. 131 § 40 in lieu of any additional requirements that might
otherwise be imposed on work in the buffer zone within the RFA;
As presented in detail in Sections 5.1.3 and 5.1.4, the Project was designed to fully
comply with the performance standards of other wetland resource areas that overlap
RFA within the Project.
10.58(4)(b) No project may be permitted within the RFA which will have any adverse effect on
specified habitat sites of rare wetland or upland vertebrate or invertebrate species … or
certified vernal pool habitat;
The Project will not have any adverse effect on specified habitat of rare species. The
Project was reviewed by NHESP and conditional no-take determinations were issued
(see Attachment H). See Section 5.1.7 for further discussion regarding rare species
and consultation with NHESP.
In addition, the following paragraphs present a summary of how the Project will fully
comply with the performance standards for redevelopment within previously
developed RFA, as per 310 CMR 10.58(5):
10.58(5) Notwithstanding the provisions of 310 CMR 10.58(4)(c) and (d), the issuing authority
may allow work to redevelop a previously developed riverfront area, provided the
proposed work improves existing conditions. Redevelopment means replacement,
rehabilitation or expansion of existing structures, improvement of existing roads, or
reuse of degraded or previously developed areas [emphasis added]. A previously
developed riverfront area contains areas degraded prior to August 7, 1996 by
impervious surfaces from existing structures or pavement, absence of topsoil,
junkyards, or abandoned dumping grounds.
The RFAs that extend into the Project Locus are previously developed from the
construction and operation of the railroad ROW, including degraded areas occupied
by the steel rails, wooden ties, and stone ballast within a linear footprint that is 11
feet wide. Therefore, all work in RFAs within the Project Site, including both the
transmission line and MCRT components, is within previously developed RFA, and
the 10-foot paved surface of the MCRT is designed to be located within the
footprint of the existing 11-foot-wide degraded area.
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10.58(5)(a) At a minimum, proposed work shall result in an improvement over existing conditions
of the capacity of the riverfront area to protect the interests identified in M.G.L. c. 131
§ 40.
The Project will result in an improvement over the existing conditions of the capacity
of the RFA to protect the interests of the Act. The Project will improve the RFA by
reducing the total footprint of the degraded area by 1 foot in width throughout the
RFA, which results in a reduction in degraded area of 1,984 square feet. In addition,
except for the 10-foot-wide paved MCRT, the remaining previously developed area
within the proposed limits of work, including existing areas of recent activity where
there is limited or no vegetation, will be restored with dense native vegetation, and
trees and shrubs will be planted at the Fort Meadow Brook crossing. Please refer to
sheet 131 in Attachment B for the proposed planting schedule.
The Project will also improve the RFA at the Fort Meadow Brook crossing. Currently,
the bridge is degraded, portions of it were burnt in a fire, and there is erosion at the
abutments. The new bridge will consist of new abutments that will be constructed
landward of the existing abutment locations and steel sheeting will be installed
around the abutments to provide scour protection. As mentioned above, this area
will also be loamed, seeded, and planted with trees and shrubs which will stabilize
the banks and enhance current conditions.
In addition to reducing the footprint of the currently degraded areas, restoring all
areas with native vegetation, and stabilizing the banks of Fort Meadow Brook to
prevent erosion, the Project will improve the capacity of the RFA to protect the
wildlife habitat interest of the Act by removing the existing rails and ties, which
extend approximately four to five inches above the ground and create a barrier to
wildlife movement, particularly for reptiles and amphibians. For example, turtles have
difficulty climbing over the rails and are therefore required to travel to widely spaced
crossing points such as existing culverts to cross the railroad embankment. The
Project will remove the obstruction and create a flat unobstructed path that is more
readily traversed by small wildlife such as turtles and migrating salamanders.
10.58(5)(b) Stormwater management is provided according to standards established by the
Department.
Stormwater management during construction will comply with all applicable
standards. Per 310 CMR 10.05(6)(m)6, the Stormwater Management Standards
(SMSs) for the post-construction phase shall apply to the maximum extent
practicable to footpaths, bike paths, and other paths for pedestrian and/or non-
motorized vehicle access. The Project was designed for the final condition of the
paved MCRT to meet the SMS to the maximum extent practicable and includes an
open stormwater system with vegetated filter strips and water quality swales with
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check dams to provide treatment. The MCRT will require 10 feet of paving and
runoff will sheet flow to the vegetated shoulders, providing an additional
opportunity for stormwater to infiltrate before it enters the swales. The swales were
designed to convey water to appropriate discharge points to maintain existing
drainage patterns and were sized such that they can accommodate a two-year storm
to meet DCR’s standards and, according to the stormwater analysis, frequently
meeting the 10-year storm requirements of the SMS as well.
The end use of the Project will be the MCRT and therefore is not anticipated to
increase pollutant loads within the Project Locus above the existing conditions. The
MCRT will be used by pedestrians and bicyclists, which will not contribute
contaminants to the path surface. Other than in emergency situations, motor vehicle
access along the path will be limited to bi-weekly mowing over the shoulders and
annual mowing over the duct bank and swales by DCR, inspections by Eversource
approximately once every three years, and other maintenance as needed by both
Eversource and DCR. In addition, the MCRT will not be plowed or treated in the
winter. Therefore, there will be little to no contaminants on the path surface to be
washed off by stormwater runoff. For additional details regarding stormwater
management, please refer to the Stormwater Report in Attachment M.
10.58(5)(c) Within 200-foot riverfront areas, proposed work shall not be located closer to the river
than existing conditions or 100 feet, whichever is less, or not closer than existing
conditions within 25-foot riverfront areas, except in accordance with 310 CMR
10.58(5)(f) or (g).
The Project is not located closer to the river than existing conditions. The existing
degraded and previously disturbed RFA extends through the entire RFA and to the
edge of the Fort Meadow Brook crossing. In addition, as discussed in 310 CMR
10.58(5)(a), the Project includes reconstructing the bridge at the Fort Meadow Brook
crossing, which will improve current conditions by installing new abutments
landward of the existing abutments, installing steel sheeting, and stabilizing the
streambanks with native vegetation to prevent erosion. The Project also provides
restoration in the form of revegetation with native species of the RFA, which is
addressed in 310 CMR 10.58(5)(f).
10.58(5)(d) Proposed work, including expansion of existing structures, shall be located outside the
riverfront area or toward the riverfront area boundary and away from the river, except
in accordance with 310 CMR 10.58(5)(f) or (g).
The Project is a redevelopment project that proposes reuse of existing degraded and
previously developed areas in the RFA. The Project Locus is a former linear
transportation corridor that currently crosses existing water bodies and their
associated RFAs. There are existing culverts or bridges at each water body crossing.
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All work associated with the Project, including both the transmission line and MCRT
components, is proposed entirely within the previously developed and degraded
area. The Project does not propose expansion of the existing degraded or previously
developed areas in the RFA.
To the extent feasible, the Project has also been designed to locate work outside of
RFA or toward the RFA boundary and away from associated waterbodies, including
manholes. To avoid and minimize the placement of manholes, they were spaced as
much as 1,900 feet apart as the curvature of the MBTA ROW allowed. Only one
manhole is located within the outer 200-foot RFA; there are no manholes within the
inner 100-foot RFA. The Project also provides restoration in the form of revegetation
of the RFA, which is addressed in 310 CMR 10.58(5)(f).
10.58(5)(e) The area of proposed work shall not exceed the amount of degraded area, provided
that the proposed work may alter up to 10% if the degraded area is less than 10% of
the riverfront area, except in accordance with 310 CMR 10.58(5)(f) or (g).
The existing degraded area is greater than 10 percent of the total previously
developed RFA in the Project Locus. Therefore, the Project is not limited to alteration
of up to 10 percent of the RFA as prescribed in this performance standard. The
Project is also proposing on-site restoration, which is addressed in 310 CMR
10.58(5)(f).
10.58(5)(f) When an applicant proposes restoration of on-site of degraded riverfront area,
alteration may be allowed notwithstanding the criteria of 310 CMR 10.58(5)(c), (d),
and (e) at a ratio in square feet of at least 1:1 of restored area to area of alteration not
conforming to the criteria. Areas immediately along the river shall be selected for
restoration. Alteration not conforming to the criteria shall begin at the riverfront area
boundary.
There is a total of 41,232 square feet of proposed temporary RFA disturbance and
23,558 square feet of proposed permanent RFA disturbance associated with the
Project. The only permanent disturbance is the 10-foot-wide paved MCRT, which will
be within the 11-foot-wide degraded area. All areas of disturbance outside of the
paved MCRT will be restored with native species, which meets the criteria of 1:1. In
addition, the Project will reduce the amount of degraded area by 1,984 square feet
by restoring the degraded area, reducing the amount of degraded RFA on the
Project Locus by approximately 1 percent.
Restoration shall include:
1. Removal of all debris, but retaining any trees or other mature vegetation;
Any debris within the limits of work will be removed as part of the Project.
Existing trees and mature vegetation will be retained wherever possible within
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the RFA. Once the Project is completed, all disturbed areas outside of the 10-
foot MCRT paved surface will be restored with native vegetation to provide a
dense herbaceous cover and trees and shrubs are proposed at the Fort Meadow
Brook crossing. Please refer to sheets 130 and 131 in the NOI plans provided in
Attachment B for planting details.
2. Grading to a topography which reduces runoff and increases infiltration;
Within the proposed limits of work, the grading has been designed to reduce
runoff and increase infiltration. The RFA will be graded flat along the MCRT but
with a slight pitch to the either side to shed runoff. The dense herbaceous
growth adjacent to the MCRT will function as a vegetated filter strip to reduce
runoff and promote infiltration of stormwater runoff.
3. Coverage by topsoil at a depth consistent with natural conditions at the site; and
The Project Site within RFA is previously disturbed, consisting primarily of a filled
embankment to support the rails and maintain a relatively level alignment.
Except for the 10-foot-wide paved MCRT, all disturbed areas within the Project
Site will be covered with a minimum of four inches of clean topsoil consistent
with natural conditions and will be revegetated with native species.
4. Seeding and planting with an erosion control seed mixture, followed by plantings
of herbaceous and woody species appropriate to the site.
A restoration seed mixture will be used throughout the Project Site, which
contains a mixture of native species including Canada wild rye, little bluestem,
fox sedge, soft rush, New England Aster, woodland goldenrod, and joe-pye
weed (see sheet 131 in the NOI plans provided in Attachment B for seed mix).
Except for the 10-foot-wide paved MCRT, this seed mix will be applied in all
areas of proposed disturbance associated with the Project, which includes
approximately 1,984 square feet of existing degraded RFA. In addition to the
herbaceous vegetation, trees and shrubs will be planted at the Fort Meadow
Brook crossing. Please refer to sheet 131 in the plans in Attachment B for the
proposed planting schedules.
10.58(5)(g) When an applicant proposes mitigation either on-site or in the riverfront area within
the same general area of the river basin, alteration may be allowed notwithstanding
the criteria of 310 CMR 10.58(5)(c), (d), or (e) at a ratio in square feet of at least 2:1 of
mitigation area to area of alteration not conforming to the criteria or an equivalent
level of environmental protection where square footage is not a relevant measure.
Alteration not conforming to the criteria shall begin at the riverfront area boundary.
Mitigation may include off-site restoration of riverfront areas, conservation restrictions
under M.G.L. c. 184, §§ 31 to 33 to preserve undisturbed riverfront areas that could be
otherwise altered under 310 CMR 10.00, the purchase of development rights within the
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