OTO_360 Riverside Drive 3rd Party Evaluation July 2022.pdf
P0285-40-01
August 1, 2022
City of Northampton
210 Main Street, Room 11
Northampton, Massachusetts 01060
Attention: Sarah LaValley, Conservation, Preservation & Land Use Planner
Re: Third-Party Review - Notice of Intent
360 Riverside Drive
Northampton, Massachusetts
Dear Ms. LaValley:
As requested, O'Reilly, Talbot & Okun Associates, Inc. (OTO) has performed a review of
the Notice of Intent (NOI) that was filed with the Northampton Conservation Commission
by Epsilon Associates, Inc. (Epsilon) on behalf of Cutlery Building Associates (CBA)
(updated April 19, 2022) for work proposed at the above-referenced property (the Site),
which is located along the Mill River. OTO has performed this third-party review at the
request of the City of Northampton.
BASIS FOR THE THIRD-PARTY REVIEW
A third-party review of the NOI was requested by the City of Northampton to determine if
the alternative provided by the applicant and selected for the project is the alternative that
will cause the least impact the wetland habitat and river resource areas. The purpose of
the review is to provide professional support to the City of Northampton Conservation
Commission in understanding if the proposed alternative should be permitted as a limited
project based upon the provisions of the Massachusetts Department of Environmental
Protection (MassDEP) Wetlands Protection Regulations, specifically 310 CMR
10.53(3)(q). The purpose of the review is not to redesign the alternative that has been
presented or provide additional alternatives to the one that was presented in the NOI, but
to evaluate whether the selected alternative and plan to implement it is the least impactful
to the riverine environment.
LIMITED PROJECT PERFORMANCE STANDARDS
Multiple alternatives to reach a level of No Significant Risk (NSR) were considered since
2011 in the Temporary Solution Report, and again reconsidered in the 2011 and 2016
Periodic Reviews of the Temporary Solution for Area of Concern (AOC)-2 and AOC-3.
Since 2011, there have been no feasible alternatives to reach NSR for the Temporary
Solution portions of the Site. Since then, funds from the pending sale of a portion of the
property made the engineered barrier alternative the best pathway to achieving NSR and
a Permanent Solution at the Site. Throughout this process, although these alternatives
were focused on the achieving NSR for the release condition, the alternatives presented
in the 2022 Phase IV RIP meet the standard of the Wetland regulations pursuant to 310
CMR 10.53(3)(q)1.
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360 Riverside Drive
Northampton, Massachusetts
August 1, 2022
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The 2021 LSP inspection of the Site identified several areas of bank stabilization efforts
that were less impactful to the resource area as ineffective in preventing erosion of
contaminated soils. Since 2005, those less impactful alternatives were performed and
although they stabilized the banks for approximately 3 years, they were not effective in
long term stabilization that could result in No Significant Risk and a Permanent Solution
for the Disposal Site.
IDENTIFICATION OF PROPOSED ALTERNATIVES AND CONSIDERATION OF
IMPACTS
Epsilon provided a single multi-step remedial alternative in the NOI. The Wetlands
Protection regulations 310 CMR 10.53 (3)(q) indicates that a Comprehensive Remedial
Alternative that is selected in accordance with provisions of the MCP (310 CMR 40.0851
through 40.0869) shall be deemed to meet 310 CMR 10.53(3)(q)(1) of the Wetlands
regulations. This section of the Wetlands regulations further states that the “…projects
shall be designed, constructed, implemented, operated, and maintained to avoid, or where
avoidance is not practicable, to minimize impacts to the resource areas…”
We developed considerations and questions in our review for each step and various
aspects of the selected remedial alternative. OTO recommends that these questions or
concerns be presented to the applicant for response and clarification.
Repoint Vertical Mortared Wall
It is unclear in the NOI if there is land to stand on at the base of the wall during the
repointing activities or if the wall is partially submerged. The application doesn’t indicate if
dewatering is required to repoint the bottom of this wall. The NOI and plan C4.4 indicate
the wall will be accessed by timber mats and the mats are located at an elevation between
the mean low water line and ordinary/mean highwater line. Our comments on timber
matting are in a separate section below.
Remove Trees & Lower the Slope of the Bank
The Mill River is identified as a cold-water fishery. Loss of tree cover and shading could
potentially influence temperature of the water altering habitat as it flows past the cleared
area. The applicant has not explained how the loss of canopy will impact the fishery and
how potential impacts will be monitored. There is special concern regarding removal of
the larger diameter at breast height (DBH) trees, as these higher canopy trees provide the
most shade. This is a short-term and long-term concern since the applicant does not
indicate in the NOI that any tree canopy restoration is planned. OTO questions if a shade
study been completed to evaluate the concern of how reduced shading could impact the
cold-water fishery.
Generally, the presence of plant roots increases bank stabilization. By cutting 96 trees
and removing their root balls, the bank may lose stabilization until matting is placed.
Although detailed excavation, fill, erosion control, mat barrier placement procedures are
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360 Riverside Drive
Northampton, Massachusetts
August 1, 2022
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provided on Plans C8.1 and C8.2, OTO has the following questions regarding this step of
implementation of the remedial alternative:
What is the timeline for each phase of work? This information would be helpful to
understand the duration of time the bank would be cleared from trees and
vegetation and exposed before stabilization activities (e.g., reinforcement with
matting);
During this period of time, how would the exposed bank be protected from erosion
from stormwater?
Are there any areas of trees, specifically larger trees, that could be retained? We
understand the concern of trees falling and destabilizing the bank. Instead of
removing the trees while they are viable, could a tree monitoring program be
implemented that would assess the viability and stability of the trees on a regular
basis, and include planned felling of trees that appear to be in poor condition or in
danger of destabilizing the bank?
Could the clearing work be performed in a step-wise, section-by-section process
that would reduce the area of soil that is disturbed and exposed at the same time?
Much of the described work will include operation of heavy equipment in or in close
proximity to multiple resource areas. Specifically, what measures will be taken to
prevent spills (which includes a sheen on surface water) to the environment? Will
there be an oil-only sorbent boom placed inside the turbidity curtain?
Is the planting of shrubs, starter plants, or saplings planned in the restoration plans
or will the area only be replanted using wetland seed mixes? Variation in canopy
height is important to restoring the habitat and providing shade to the cold-water
fishery. There are additional concerns regarding the loss in shading in uplands
habitat and potential temperature changes due to loss in canopy cover and the
impact on the habitat of the endangered species (Ocellated Darner) identified in
this area.
Re-build Collapsed Dry-laid Stone Wall
OTO has the following questions regarding the re-building of the dry-laid stone wall to
support the levee:
Is the re-build only adding to the height of the wall?
Where are portions of collapsed dry-laid stone wall?
What is the length collapsed portions of wall to be rebuilt?
Was there consideration to rebuild this area as a gabion wall if there are intact
areas of the base of the wall?
Will there be any replication for the loss of wetland area for the installation of the
dry-laid bolder retaining wall located to the west of the isolated wetland?
Long term, this wall may improve the wetland holding capacity. Would a replication
area improve the applicant’s ability to meet the general performance standard?
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360 Riverside Drive
Northampton, Massachusetts
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Gabion Wall
OTO has the following question regarding the installation of the gabion wall:
Where are the sections of the collapsed wall located? We were unable to identify
specific portions of the wall that are compromised on the plans provided by the
applicant.
What is the length of the collapsed wall to be replaced with gabion wall?
Extend Retaining Wall
OTO has the following questions regarding the extension of the retaining wall:
During construction, how will intermittent increased stream flow and stage changes
in the Mill River due to unexpected storms be managed?
In areas where a turbidity curtain is used around the timber matting, is the curtain
where it is attached to the bank placed at a high enough elevation to withstand the
fluctuation in river water?
The implementation plan indicated that a silt fence will be placed along the
shoreline even where there is a turbidity curtain. The plans be adjusted to depict
this.
OTO suggests that the stones used to extend the walls should not be collected from the
riverbed but should be brought in from an outside source if they are not from a previously
collapse portion of the wall. As noted on Page 12 of the NOI, habitat for the endangered
Ocellated Darner includes shaded, clear, cold, rocky streams and rivers and associated
shaded uplands. OTO has concerns that removing native rocks from the streambed may
further degrade the habitat of the dragonfly, which is already being altered by the removal
of shading trees and other plantings.
Stone Rip-Rap
OTO notes that rip-rap rock is actually good for the identified endangered species habitat
as long as there is enough shading. This could be considered an improvement for the
habitat especially because the habitat some has already been lost due to the last
expansion of the stockpile.
OTO has the following question regarding the rip-rap placement above the retaining wall:
Is this area part of the engineered barrier? Will the fabric, gravel, and rip-rap need
to be surveyed in between each stage for the AUL?
Geocell Turf Reinforcement Mat Treatment
OTO has the following questions regarding the geocell turf reinforcement mat that is
planned along the reworked slope above the rip-rap.
Is this area considered part of the engineered barrier?
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Northampton, Massachusetts
August 1, 2022
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If it is not within the engineered barrier, can any saplings be planted along this
slope? Saplings and their root structures could be beneficial as they act as natural
anchors for the matting in addition to providing shade and variable heights of
canopy.
Soil Stabilization
OTO has the following questions regarding the application of metals stabilization materials
to soils along the levee and the levee bank to the top of the stone retaining wall:
Will soils that are assumed to be contaminated located at the base of the
excavated grade be treated with Blastox before the filter fabric in rip-rap area or
geocell mat is placed?
The application of the Blastox metals stabilization materials will occur in situ and
require soil mixing. What measures will be taken to prevent accidental releases of
the Blastox to the waterway? How will materials be stored on Site?
Will application timing be limited to dry conditions to eliminate Blastox material from
running off into a resource area creating unintended treatment of river sediment,
potentially impacting the uptake of natural minerals within that resource area. A
response to these questions could be provided in a spill prevention plan.
If the Blastox application will result in stabilization of the metals-contaminated soil
such that the metals are no longer leachable, what is the reasoning for stockpiling
the soil? If the metals are no longer leachable, the materials could theoretically be
eligible for transportation as non-hazardous remediation waste and would
eliminate the need for expansion of the stockpile.
Was excavation of the soil, stockpiling, and treatment in an area away from the
riverbank followed by disposal after treatment considered?
Stockpile Excavated Soil
The original plans submitted in the NOI discussed work within the southern end of the
Isolated Wetland. Revisions submitted by the applicant indicate that loss of the southern
end of the Isolated Wetland is no longer a concern. OTO has the following questions
regarding the stockpile:
Based on the revisions, an area that has a UCL exceedance will not be capped by
the engineered barrier. Will a Permanent Solution with Conditions still be
achievable if this area is not capped?
Is the stockpile engineered barrier permeable? Is an impermeable membrane not
required because the soil is being treated with Blastox?
Instead of the stockpile being stabilized with grass, would the applicant consider a
pollinator mix and a wetland mix on the northern end of the stockpile?
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Northampton, Massachusetts
August 1, 2022
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Has additional stormwater runoff from the stockpile to the parking lot to the south
been considered? From our limited site visit (from the street), we have concerns
about the holding capacity and competency of the existing stormwater outfall if an
impermeable membrane is used on the stockpile. Additionally, OTO questioned
whether a stormwater management will be in place during implementation
activities?
OTO recommends the limits of the final stockpile not to exceed existing dimensions. If soil
quantities to be excavated and moved to the stockpile exceed the pre-approved stockpile
limits, shipment off Site for disposal should be considered.
Removal of Organic Matter
OTO has the following questions regarding the removal of organic matter along the
riverbank:
What is the nature of the timber matting that will be used for the log-mat road and
the road parallel with the levee? Our concern is that the wood for the matting could
contain creosote or arsenic soaked wood if they are constructed from former utility
poles or railroad ties. Do these types of timber mats have treatments that could
impact resource areas? Note: A sheen observed on a surface water is a reportable
release condition.
How does the lower area access road connect to the construction entrance?
Where is the access road? Is the planned access road permanent or temporary?
Can the work be performed on the access road without the width of the access
road being 36’ wide? Additional questions regarding the access roads are provided
in the following section.
Can the crane stabilization areas be defined and kept outside of the Isolated
Wetland (IW)? The Erosion controls plan depicts silt fence around IW and Site
preparation plan (C4.3) depicts timber map placement across more than ½ of the
IW.
OTHER PROJECT SPECIFICS
OTO has the following general questions regarding implementation of the remedial
alternative and its potential for temporary or permanent impacts to the wetland:
Access Road
We would like additional details regarding the constructed 12’ wide access road.
Is this a permanent or temporary disturbance? Will compacted sublayers be
removed? Will there be other plantings or just seeding? Will this be installed with
the intension of using it to access the area by foot or by vehicle in the future? If
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360 Riverside Drive
Northampton, Massachusetts
August 1, 2022
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vehicular traffic is not planned once the excavation and stabilization work is
completed, can native shrubs or trees be planted along or within this access road?
Once the remedial alternative has been implemented, will the planned construction
entrance be restored?
Post-Excavation Sampling
There are 20 proposed post-excavation samples planned for a 35’ x 650’ area. Is
this sampling frequency adequate to demonstrate effectiveness of the Blastox
application? OTO would recommend that TCLP testing also be performed to
confirm that the application has effectively stabilized the metals.
Engineered Barriers
What are the planned limits of the engineered barrier(s)? There are several types
of engineered barriers planned. Since leachability of metals is being stabilized
through the application of Blastox, it appears each of these barriers is permeable.
If it is permeable, is it possible to replant saplings anywhere there is not an
engineered barrier required for the AUL?
Will the fabric under the rip-rack rock be considered an engineered barrier?
Fencing
As part of the requirements of the AUL (specifically related to arsenic), will the
chain link fence need to be restored?
Post Completion Monitoring
The current post-completion monitoring plan sets a goal of 75% cover after two
years. Past erosion control measures implemented at the Site have lasted
approximately 2-3 years before erosion began. OTO would recommend monitoring
for five years to ensure the erosion controls are effective for at least as long as the
temporary controls that have previously been implemented. Specifically, higher
frequency monitoring should occur in initial months following completion of the
alternative, followed by a reduction in frequency over the next few years. The
monitoring program should require inspections following spring highwater and after
large storm events.
The plan did not specify the post-implementation duration, or frequency of
temperature monitoring of the Mill River to evaluate the long-term impacts of the
removal of shade plantings. OTO also had questions regarding the monitoring of
water quality changes in the river and whether the post-completion monitoring
program accounted for large storm events and changes in the river level.
As noted above, OTO would recommend the planting of starter plants, wetland
shrubs, or saplings in addition to the wetlands mix to increase the height variability
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360 Riverside Drive
Northampton, Massachusetts
August 1, 2022
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and coverage of the canopy in areas where practicable and where the plantings
do not interfere with engineered barriers.
Restoration or Replication
As noted above, OTO believes that alternative restoration and/or replication of
wetland habitats may be possible that would reduce the overall long-term impact
of the project on these wetlands.
Additional Mitigation Measures
If large areas of the project area are to be unvegetated for a substantial period of
time during the implementation of the remedial alternative, OTO would recommend
the placement of dust monitors upwind, downwind, and at the southern end
(closest to the nearest inhalation receptor). OTO would recommend logging
intervals of 30 minutes. OTO also recommends that dust suppression should be
supplied by a contractor-provided water source (tank trailer). The plan should
stipulate that the source of dust suppression water will not be the Mill River.
OTO personnel are available to attend a Site visit and/or attend conservation commission
meeting(s) with the Site owners, the LSP-of-record, and city officials, if requested. These
services can be provided on a Time and Materials basis in addition to the proposal we
have fulfilled by completing this review.
We thank you for the opportunity to provide our services to the City of Northampton.
Sincerely yours,
O'Reilly, Talbot & Okun Associates, Inc.
Sabrina A. Moreau Lori McCarthy, LSP
Project Manager Senior Project Manager