REVISED-NHESP_Phase IV RIP-Wall Repair Alternatives Analysis 2022-04-18Mansfield, MA Amherst, MA Chester, VT
Phase IV RIP MEMO – Wall Repair & Alternatives Analysis
Date: April 18, 2022
RE: Former Cutlery
360 Riverside Drive
Northampton, MA 01060
NHESP Tracking No.: 12-31337
RTN: #1-13220
OHI Project #13-1515
A Phase IV Remedy Implementation Plan (RIP) for the Former Cutlery (OHI, February 8, 2022)
was submitted to MassDEP BWSC and a corresponding Notice of Intent (NOI) was submitted to
the Northampton Conservation Commission. Copies of these documents were submitted to the
Massachusetts Natural Heritage & Endangered Species Program (NHESP) who provided a letter
dated March 25, 2022 requesting additional information. This memo provides responses (in
plain text) to the requested additional information (in italics) below. Cutlery Building Associates
is mandated by MassDEP BWSC and the MCP to implement a Permanent Solution for this Site,
and the Phase IV RIP details how this can occur. OHI has chosen repair options that will last,
using our experiences at this Site and Professional Engineering standards.
1) Alternatives Analysis: Assessment must explore options for the feasibility of bioengineering or
hybrid bioengineering/hardened solutions for the existing wall repair and the proposed
stabilization; in particular, alternatives to the proposed gabion baskets and dry laid boulders.
The Site is the former raceway that carried water from the Mill River to the former Northampton
Cutlery mill building. A steep bank separates the former raceway from the east bank of the Mill
River, approximately 15 feet below. The course of the former raceway follows a long, relatively
flat strip of land approximately 40 to 60 feet wide. The strip extends in the north-south direction
and is bordered on the east by Riverside Drive. A slight rise of 5 to 10 feet and a guardrail
separates the flat strip of land from the road. The former raceway is not directly visible at most
of the ground surface because it has been filled and is now covered in different portions by trees,
shrubs, organic debris, and the Cutlery Building and Valley Home Improvement parking lots.
The course of the raceway has been determined by using historic maps and inspections of ground
topography. The downstream end of the raceway abuts the back (western-most) portion of the
Cutlery Building. Following its course upstream it then winds north through (under) the now
paved parking lots of the Cutlery Building (Lot 32) and Valley Home Improvement (VHI, Lot
76) behind the former firehouse building, and then continues in the narrow strip of undeveloped
land between Riverside Drive and the Mill River to the northern portion of Lot 77, where water
entered the raceway at a former dam. The raceway was built in the mid 1860’s and carried water
110 Pulpit Hill Road
Amherst, MA 01002
Tel (413) 835-0780
www.ohiengineering.com
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 2 Northampton, MA
until the mid-1900’s. Sometime in the 1940’s, or 1950’s the water from the raceway was no
longer needed and it was drained. For the next 20 to 30 years, the southerly portion of the
raceway, extending approximately 600 feet north from the Cutlery Building (400 feet into Lot
77) was used as a dumping site for household garbage, demolition debris, and industrial wastes.
The levee that separates the raceway from the river has also been found to contain hazardous
materials (metals). The levee becomes topographically prominent from approximately 600 ft to
880 ft north of the Cutlery Building, where the former raceway has not been filled. The Site has
been divided into three Areas of Concern (AOC):
AOC-1: This portion of the Site includes the northwestern portion of the southerly
Cutlery Lot 32 and the western portion of the Valley Home Improvement (VHI) Lot 76
as shown on Figures 3 and 5. This includes the paved parking lots behind the Cutlery
building and the VHI building and the sloped bank down to the Mill River west of these
parking lots.
AOC-2 and AOC-3: These areas of the Site occupy the narrow strip of undeveloped land
between Riverside Drive and the Mill River, from the northern VHI property line to the
northern portion of Lot 77, where water entered the raceway at a former dam (Figure 3).
AOC-2 includes the filled portion of the raceway, but does not include the bank of the
Mill River west of this section. AOC-3 includes the entire exposed levee from the
northerly end of AOC-2 north to the chain link fence at the north end of the Site.
Alternative remediation strategies and bank repairs at this MCP Site have been evaluated and
submitted to MassDEP several times in the past:
Phase II – Comprehensive Site Assessment (Phase II) & Phase III – Identification,
Evaluation and Selection of Comprehensive Remedial Action Alternatives Report (Phase III),
by NEE, October 2003.
Multiple remedial options were evaluated and different solutions chosen for each of the three
AOCs at the Site.
MCP Phase IV Remedy Implementation Plan (RIP), by NEE, August 2004
The following remedial options were considered the best alternatives for the areas of concern (AOC) at
the Site.
AOC-1: Excavate hot spots from under the parking lots and consolidate this material within AOC-2
(completed). Pave the parking lots and place an AUL on the new pavement areas for the
residual metals-impacted soil.
AOC-2: Consolidate the excavated soil from AOC-1 and AOC-3 in this area and either a)
phytoremediate the metals, or b) stabilize the metals in place.
AOC-3: Excavate hot spots and other impacted soil off the top of the levee and consolidate this material
within AOC-2 (started). The goal in this area was to achieve Method 1 soil standards.
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 3 Northampton, MA
Phase IV – Interim Construction Report, by NEE, August 2, 2005
MCP Phase IV REVISED Remedy Implementation Plan, by NEE, September 2005
Problems were encountered with some of the RIP tasks. The tasks were revised and submitted to
MassDEP and Northampton Conservation Commission who then requested a Comprehensive NOI for the
Site.
REVISED Remedy Implementation Plan, by NEE, May 2006
Comprehensive NOI
AOC-1: In all areas where exceedance of an Upper Concentration Limit (UCL) of any metal was
identified, this material was removed, and consolidated in the stockpile in AOC-2. West of
the Cutlery Building and Firehouse, the remaining metals-impacted soil along the bank
leading down to the Mill River were physically stabilized in place and an AUL was extended
from the parking lots down to the river’s edge. A chain-link fence was erected along the west
side of the parking lots in AOC-1 to restrict access to the bank.
The surface of the bank was stripped of small brush and vegetation, and then covered in a
marker layer of bright orange, plastic, construction-type fencing that was laid down around
the existing trees. The marker layer was then covered with four to six inches of cover
material and loam, then covered with erosion control landscape fabric, and planted with
materials designed to physically stabilize the bank against future erosion. A coconut bio-log
was installed at the toe of the slope within AOC-1 to anchor the fabric layers and reduce
possible erosion by the Mill River of the lower portions of the new installations.
West of the Cutlery Building where the bank was near-vertical, it was unrealistic to assume
that even four to six inches of soil would stay on the bank. Some areas of this bank were
boulders, and these were not covered with soil and planted. In the remaining areas, soil was
placed between the large rocks and covered with an erosion-control fabric to help hold it in
place prior to being planted with materials designed to physically stabilize the bank against
future erosion. At the base of established trees, the soil layer was reduced to zero so that the
trees’ root systems and trunks are not suffocated.
This alternative solution, completed in 2007, left most of the contaminants in place at the Site, but in a
stabilized form that would not be available to the environment. It also placed the worst of this material in
a location farther from the Mill River (stockpile within AOC-2) or used it to protect the river from likely
future degradation (AOC-1).
Cutlery Raceway Slope Stabilization, by NEE, Summer 2010.
In AOC-1 behind the Cutlery Building, 130 linear feet of eroding bank was restored immediately
upstream of the tailrace. Much of this area had been covered in erosion control fabric and bio-logs in
2006/2007, but those materials did not withstand the flood water forces of the Mill River and needed a
stronger solution.
Coir bio-logs were anchored in at the toe of slope with CF 700 fabric secured underneath. The first geo-
lift consisted of one foot of loam blown into place on a fold of the CF 700 fabric creating a 4’ shelf,
which was then seeded and the fabric was pulled up and over to stabilize the lift. This process was
repeated two additional times creating three pillows of seeded loam. Saplings were planted between each
geo-lift. The remaining slope above the three geo-lifts was covered in CF 700, and sprayed with loam
and seeded.
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 4 Northampton, MA
Cutlery Raceway Slope Stabilization, Wetland Restoration Monitoring Report, by NEE to
Northampton Conservation Commission, November 16, 2010.
In 2010, the bank stabilization work at the Site was assessed, including vegetational cover as required by
the Order of Conditions.
Stabilized Slope Adjacent to Cutlery and Firehouse (AOC-1)
This area was stabilized under the 2004 Order of Conditions and the 2007 “revised remediation plan.”
Work was done around pre-existing trees. Portions of this area had slopes over 3:1, and the orange
fencing was visible in sections on the slope. In addition, this area was minimally disturbed, with the
primary activity covering the soil with orange fencing, which was then loamed and seeded. This area did
not have any signs of erosion. The area was minimally disturbed and shows no signs of erosion after
three years.
2010 Repair Area - Upstream
Immediately downstream of the above area was an area of repair that was completed in spring 2010.
Unlike the above areas, this area was becoming undercut and was eroding. The total length of this repair
was 30 linear feet. Repairs consisted of creating geo-lifts at the toe of the slope with brush layered
between them, and soil covering the slope, seeded and covered with an erosion control blanket staked into
place. The vegetative cover of this area was approximately 20%. The vegetation was growing well and
there was no further sign of erosion.
2010 Repair Area – Downstream
A second area of bank repair was completed downstream and near the Cutlery Building in 2010. This
area also was becoming undercut and the repairs were similar to the above. This area was 130 feet in
length, and consisted of biologs and geo-lifts at the toe of the slope with brush layering, and loam and
seed were placed on the upper slope, which was then covered with an erosion control blanket.
Cutlery Raceway Slope Stabilization, by NEE, Summer 2012.
In AOC-1 behind the Cutlery Building, flood water damage required a CF 700 patch at the downstream
end of the 130 linear feet of eroding bank that was restored in 2010.
In AOC-3, erosion repair was necessary along 93 feet of the bank above the dry-laid stone wall. A
portion of the stone wall required rebuilding in order to create a stable base for this repair. Coir bio-logs
were anchored in at the toe of slope above the wall, with CF 700 fabric secured underneath. A single geo-
lift consisting of one foot of loam blown into place on a fold of the CF 700 fabric creating a shelf, which
was then seeded, and the fabric was pulled up the remaining slope and secured with landscape staples.
The geo-lift and CF 700 were sprayed with loam and seeded. Two sections of the 93 feet had less severe
erosion and were treated with a lighter straw blanket.
ClassA3 RAO-P & ClassC1 RAO-P Statements, by NEE, February 2011
The extent of the disposal of industrial waste materials, demolition debris, and common refuse in an
unregulated landfill within and along the former raceway leading to the Cutlery Building was identified.
Soil that exceeded the UCL in AOC-1 was excavated and moved to the stockpile in AOC-2.
For the Area AOC-1, a Permanent Solution was achieved, the level of OHM in the environment was not
reduced to background and an Activity and Use Limitation was implemented. The EPCs for identified
OHM material at the disposal Site did not exceed any UCL in soil and groundwater, therefore this portion
of the Site was eligible for a Class A3 RAO.
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 5 Northampton, MA
For the portion of the Site labeled AOC-2 & AOC-3, a condition of No Substantial Hazard existed,
response actions to achieve a permanent solution were not currently feasible, and an Activity and Use
Limitation was implemented. This portion of the Site was eligible for a Class C1 RAO.
Periodic Review of Temporary Solution, by OHI, February 17, 2016
AOC-2 and AOC-3 were each closed in February 2011 with a Class C-1 RAO-P. In accordance with 310
CMR 40.1055(3), the Site was considered to have achieved a Temporary Solution With Conditions,
which was the subject of this Periodic Review. The following remedial alternatives were considered
during this five-year review: No Further Action, Monitored Natural Attenuation (MNA), Stabilization and
Disposal of TCLP Metals, Stabilization of All Metals and Leave On-Site, Excavate & Off-Site Disposal,
Engineered Barrier, and Phytoremediation.
It was not feasible to achieve a Permanent Solution at the Site at that time. The contaminants did not
appear to have dissipated over time and were not likely to decompose via a process of unassisted
microbial action. Therefore, monitoring the status quo did not appear to meet the remedial objectives of a
Permanent Solution for the Site, but was an appropriate action under the Temporary Solution.
LSP Annual AUL Inspection Reports (2011-Present)
Annual AUL inspection by an LSP and reports submitted to MassDEP have been conducted and
submitted since 2011 when the original RAO-Ps were submitted. Limited repair work to the bank of the
Mill River was an outcome of several of these inspections.
2020 Erosion Repair Work
During the August 6, 2020 site inspection, Mr. Lyons Witten, LSP noted six areas along the upper levee
in AOC-3 where the bank was found to be eroding, and erosion noted at the tailrace stone wall (upriver
side) at the downstream end of AOC-1.
The identified erosion areas were repaired in October 2020 using straw blanket fixed to the slope using
six-inch landscape staples and woody material already on the slope. Orange marker layer was replaced
where missing. Straw wattle held in place with wooden stakes was used at the toe of each section to affix
the straw blanket (and orange marker layer in AOC-1). The AUL Annual Inspection Report submitted on
February 17, 2021 outlined erosion control repairs completed as a result of issues identified during the
2020 annual AUL inspection.
Periodic Review of Temporary Solution, by OHI, February 17, 2021
AOC-2 and AOC-3 were each closed in February 2011 with a Class C-1 RAO-P. In accordance with 310
CMR 40.1055(3), the Site was considered to have achieved a Temporary Solution With Conditions,
which was the subject of this Periodic Review. The following remedial alternatives were considered
during this five-year review: No Further Action, Monitored Natural Attenuation (MNA), Stabilization and
Disposal of TCLP Metals, Stabilization of All Metals and Leave On-Site, Excavate & Off-Site Disposal,
Engineered Barrier, and Phytoremediation.
It was not feasible to achieve a Permanent Solution at the Site at that time. The contaminants did not
appear to have dissipated over time and were not likely to decompose via a process of unassisted
microbial action. Therefore, monitoring the status quo did not appear to meet the remedial objectives of a
Permanent Solution for the Site, but was still an appropriate action under the Temporary Solution.
Phase IV Remedy Implementation Plan (RIP), by OHI, February 8, 2022
Following the February 2021 evaluation, an LSP inspection of the Site after spring snow melt
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 6 Northampton, MA
revealed that additional portions of the retaining wall along the base of the headrace levee were
in poor condition and had at least partially collapsed in multiple locations and that above each
area of wall collapse was an area of increased bank erosion. Where the retaining wall at the base
of the levee had collapsed, or started to, are areas where bank erosion control maintenance had
been previously required. The bank restoration areas requiring maintenance in October 2020 are
particularly evident above areas of collapsed retaining wall. The levee retaining wall was built in
the 1860s and has never undergone significant repairs; it is in remarkably good condition, but it
is starting to fail in critical areas and is in need of significant repairs in order to maintain the
stability of the area and prevent erosion to the river.
Cutlery Building Associates has maintained the levee bank via more-or-less annual bank
stabilization measures. These measures slow the soil erosion into the Mill River, but the overall
impact of a slowly degrading retaining wall is that there is more and more erosion of the bank
into the Mill River. The 100-year flood elevation is well above the top of the retaining wall
along almost all of the length of this project, and flood waters have a long-term role in the
degradation of the retaining wall. The 100-year flood elevation is depicted accurately on the
Riverbank Restoration plan set (OHI, 2022).
The Phase IV RIP involves restoration of the retaining wall along the base of the former Cutlery
headrace levee from its upstream origin downstream to the vicinity of MW-4 where a wider
flood plain area dissipates the energy of the Mill River. The goal of the proposed work is to
prepare the Site for a Permanent Solution with Conditions under the MCP.
The continued evaluation of potential closure options under the MCP and the degradation of the
levee retaining wall have resulted in the preparation of this Phase IV RIP to implement retaining
wall and bank restorations that are designed to help the levee withstand the forces of the Mill
River for the next 100-plus years. This retaining wall and bank restoration project coincide with
the possible sale of one of the Cutlery mill buildings. This pending property transfer will
provide the funding necessary to implement the necessary repairs. This is a one-time
opportunity to privately fund significant and necessary repairs to the levee retaining wall and the
bank it supports as part of achieving a Permanent Solution.
Summary
In considering the design options for this retaining wall restoration, OHI reviewed the prior bank
stabilization designs and strategies.
The compost pillow geo-lifts employed in AOC-1 in 2006, 2010, and in AOC-3 in 2012
have little compost left in them and needed repair in 2020 and 2021. This construction
detail/design works well in low water energy areas of this Site, but is not substantial
enough to withstand annual spring flood water forces below the 100-year flood elevation;
The straw blankets and coir wattle repairs last several years after installation and then all
that remains is the poly netting within them and they become less effective. Areas within
AOC-3 treated with straw blanket have required additional erosion repairs within 5 to ten
years;
Bioengineered solutions have not been successful over the long term at this Site,
especially in areas of high flow velocities. They require regular repair and maintenance
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 7 Northampton, MA
and would not be a suitable option to achieve the required Permanent Solution;
Full excavation of metals-impacted soil is financially infeasible. Therefore, the metals-
impacted soil must be covered in place in a manner that makes them inaccessible and
keeps them in place for many generations;
The bank is too shaded for most of the plantings that have been attempted over the last
decade to become established;
As more of the stone retaining wall fails due to the water forces of the Mill River, more
of the bank above it will end up in the river, along with its entrained heavy metals. This
is a vicious cycle, since the more the wall degrades, the easier it is for the Mill River to
rip more of the wall from the bank;
OHI evaluated a number of “hard” solutions and chose the most natural materials
available for various areas of the repair. The stone wall will be repaired using stone and
gabion baskets filled with stone. The 100-year flood plain above the wall will have stone
rip-rap installed to hold the bank in place during times of flooding. The slope above will
have turf mat and native grasses. The entire slope angle will be relaxed in order for the
installation package to withstand the forces of the Mill River for generations to come;
and,
105 feet of new stone wall will be installed to help the most downgradient portions of the
newly-relaxed steep slope stay in place. This is in addition to 56 lineal feet of repaired
existing wall below Ordinary/Mean High Water and above Land Under Water Body.
Cutlery Building Associates is mandated by MassDEP BWSC and the MCP to implement a
Permanent Solution for this Site, and the Phase IV RIP details how this can occur. OHI has
chosen repair options that will last, using our experiences at this Site and Professional
Engineering standards.
2) Impact Calculations: Provide clear impact calculations (cumulative square footage) associated
with the temporary construction matting proposed riverward of the existing walls; and
excavation associated with wall replacement with gabion baskets.
The requested impact calculations are provided in the Revised NOI dated April 2022, along with
the previously provided square foot calculations of impacts within wetland resource areas.
3) Site Plan Revisions: The site plans must be revised to detail:
a) Depict the ordinary high‐water line in relation to the elevations of the existing wall;
Ordinary High-water is coincident with Mean Annual High Water at this Site. Labels on the plans have
been changed to make this clear.
b) It appears that construction matting and equipment access is proposed below MAHW. The
plans must include the proposed construction matting layout, access, and anchoring
methods.
Construction matting layout below MAHW has been added to the plans.
Wall Repair Alternatives Analysis RTN #1-13320 Former Cutlery
OHI Project #13-1515 360 Riverside Drive
April 18, 2022 Page 8 Northampton, MA
c) The cross sections of bank stabilization methods (Types A‐D; Sheet C8.2) do not include
MAHW or a range thereof. Further clarification regarding excavation of soils below MAHW,
MALW, particularly in relation to the installation of gabion baskets. The plans must be
revised to include these clarifications.
A Profile Plan has been added to the plans as sheet C10.1