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Cutlery Response to OTO Letter re NOI (updated November 3 2022).pdf1 RESPONSES OF THE APPLICANT TO THE ISSUES/QUESTIONS IN OTO’S LETTER DATED AUGUST 1, 2022, re: the revised Notice of Intent for 360 Riverside Drive. Updated responses are included on pages 10 and 11 below to address confusion between the “construction entrance” near Riverside Drive and the “lower area maintenance road,” which became apparent upon reviewing Specific Permit Condition #3 included in the Northampton DPW Stormwater Management Permit APPLICATION DECISION signed on 10/18/22. According to the OTO letter: “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. OTO stated that they developed considerations and questions in their review for each step and various aspects of the selected remedial alternative. OTO recommended that these questions or concerns be presented to the applicant for response and clarification. Although many of the considerations and questions presented by OTO actually appear to suggest a redesign of the selected MCP alternative and are not limited to an evaluation of impacts to the riverine environment, responses and clarifications from the Applicant are presented in italics below to all of the items listed in the OTO letter, which are reprinted in standard font. 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. When water levels are low, there is dry land at the base of the wall. This area contains many cobbles and boulders. If the contractor determines that they can safely utilize ladders from the land below to access upper sections of the wall, they will do so. If timber mats will increase safety, or if water levels are high enough that mats are required to access the area, then timber mats will be used. These provisions are included in the plans in order to provide some flexibility to the contractor given Site conditions at the time of work. If mats are used due to the land at the base of the wall being wet, then the mats will be anchored so that they stay in place. Dewatering is not required to construct the project. 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 2 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. NHESP issued a no take determination on the habitat of the listed endangered species. This determination was made in response to the restoration plan as provided to NHESP, MADEP, and the Commission, which includes just using native wetland and upland seed mixes. Due to the diverse native overstory of large diameter trees in the vicinity of the project, larger shade providing trees and shrubs are expected to naturally populate the area. While the project is proposed on the eastern Bank of the Mill River, which receives sunlight from the west/south west, there are many large trees on the western Bank that do, and will continue to, provide shade to this section of the river. Additionally, the Mill River has perennial flow in this section and there is no pooling water in the vicinity that is exposed to sunlight. The change in shading will therefore be limited and short-term, and are off-set by the benefits of the Bank stabilization, which include a significant reduction of erosion and sedimentation of contaminated materials into the Mill River. 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 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); Tree removal will be accomplished by a tree removal company using chain saws and a crane. They estimate this will take two to three weeks total. We anticipate the tree removal to be accomplished when the ground is frozen in January or February 2023. The stumps will remain on the bank until the excavation contractor arrives to ease the slope. • During this period of time, how would the exposed bank be protected from erosion from stormwater? We anticipate that there will be little risk of erosion during those winter months. The erosion control barrier shown on sheets C7.x will be in place prior to tree removal and will remain for the duration of the project. 3 • Are there any areas of trees, specifically larger trees, that could be retained? There are two or three trees at the southern end of the work area, near MW-4, that may be able to be retained if the contractor determines that their equipment can access the area near the river without their removal. • 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? This question was considered multiple times during the design phase as different reviewers looked at the plans. The problem at the Site is erosion of metals- impacted soil into the Mill River from the overly steep bank. The selected solution to eliminate this erosion is to relax the slope, make it less steep, cover the remaining metals-impacted soil, and protect it with a surface able to withstand the forces of the Mill River during flood stage. This is not practical to do in piece- meal fashion. From a construction point of view, all the stumps must be removed as the bank is relaxed and then protected. The project needs to be done at one time, although it will be done one section at a time in order to minimize erosion. • 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? The planned construction sequencing includes stump removal to be accomplished step-wise, section-by-section as each section of bank slope is eased and re-covered with rip-rap and geocell. The Mirafi geosynthetic fabric that will first go down on the relaxed slope comes in rolls that are typically 15-17 feet wide, so each section of work on the bank will be approximately 15 feet wide. • 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? The contractor will have a “Spill Kit” at the construction trailer which includes sorbent booms and pads. No equipment will be left overnight on the area near the river below the retaining wall. An oil-only sorbent boom will not be installed 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 4 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. As noted above, NHESP issued a no take determination on the habitat of the listed endangered species. This determination was made in response to the restoration plan as provided to NHESP, MADEP, and the Commission, which includes just using native wetland and upland seed mixes. Due to the significant overstory of large diameter trees in the vicinity of the project, larger, shade providing trees and shrubs are expected to naturally populate the area. There are many large shade providing trees on the western Bank of the river. Additionally, the Mill River has perennial flow in this section and there is no pooling water in the vicinity that is exposed to sunlight. 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? Rebuilding of existing stone retaining walls will be to the estimated height of the original wall, as observed by the highest portions of the stone retaining wall nearby that do not appear to have collapsed. The dry-laid stone wall starts at approximately six feet high at the downstream end of the mortared section of wall, and gradually reduces in height to approximately two feet at the southern end. Most of the stone retaining wall is approximately four feet high. • Where are portions of collapsed dry-laid stone wall? Partially collapsed dry-laid stone wall is identified as Type B on sheets C5.x and C6.x. The repair schematic for each type of wall repair/replacement is shown on the Construction Details sheet C8.2. • What is the length collapsed portions of wall to be rebuilt? The Type B wall sections are provided on sheets C5.x and C6.x and show that there are four sections ranging in length from two feet to 19 feet with a total combined length of 55 feet. • Was there consideration to rebuild this area as a gabion wall if there are intact areas of the base of the wall? 5 Where there is existing wall that is still partially intact, we chose to rebuild, instead of demolishing more of the existing wall and then replacing with gabion. Where there is little of the existing wall left, we chose to replace with gabion as that will be the stronger solution for those areas. Rebuilding the entire wall with gabion baskets is economically infeasible. • Will there be any replication for the loss of wetland area for the installation of the dry-laid boulder retaining wall located to the west of the isolated wetland? There are no plans for wetland replication of this small area. Stormwater from the Riverside Drive catch basins discharges to this isolated wetland via a corrugated metal pipe. The wet area increases and decreases with seasons based on the street drain input. There is no discharge from this 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? There is no current issue with this isolated wetland’s ability to hold water. The replacement wall is not anticipated to change this one way or the other. • Would a replication area improve the applicant’s ability to meet the general performance standard? The general performance standard for BVWs does not apply because this is an isolated wetland that is not subject to MassDEP regulations. 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. Collapsed dry-laid stone wall is identified as Type C on sheets C5.x and C6.x. The repair schematic for each type of wall repair/replacement is shown on the Construction Details sheet C8.2. • What is the length of the collapsed wall to be replaced with gabion wall? Review of Type C wall sections on sheets C5.x and C6.x shows that there are four sections ranging in length from 18 feet to 114 feet with a total combined length of 236 feet. Extend Retaining Wall OTO has the following questions regarding the extension of the retaining wall: 6 • During construction, how will intermittent increased stream flow and stage changes in the Mill River due to unexpected storms be managed? Work on the retaining wall will be scheduled for months when there are lower water levels in the Mill River. Since the wall repairs/replacements and bank slope easing will be done section-by-section, the weather forecast can be monitored prior to beginning work on each new section of retaining wall and periods of expected heavy rainfall will be avoided. • 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? Yes. • The implementation plan indicated that a silt fence will be placed along the shoreline even where there is a turbidity curtain. Erosion Control sheets C7.x depict the erosion control barrier and the turbidity curtain overlapping, but the erosion control barrier is not shown along the entire inside length of the curtain. The plans will be adjusted to show erosion control barrier along the entire length of the project work area adjacent to the Mill River. • 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. The intent is to utilize stones from obviously collapsed portions of the wall to rebuild the wall, not to mine the riverbed for other stones. If more stones are needed, they will be imported from off-Site. • 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. There is no intent to remove or mine native stone from the riverbed in the NOI or other written plans. As indicated, we will only utilize stones from obviously collapsed portions of the wall to rebuild the wall, but not mine native stones from the river bed. 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 7 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? The orange fabric, crushed stone and rip-rap are designed to be a risk reduction barrier to prevent dermal contact with remaining underlying impacted soil. The location of the various materials will be surveyed for the As-Built Plans produced after construction. We do not intend to survey the location/elevation of each material for the purposes of 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? Yes. The filter fabric, clean fill, loam and turf reinforcement mat are designed to be a risk reduction barrier to prevent dermal contact with remaining underlying impacted soil. • 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. The geocell mat/blanket is designed to be filled with soil and seeded, allow water to pass through, and to hold the bank in place to impede erosion. Saplings will not be planted in the geocell area as they will grow into trees which will eventually fall over and disrupt the bank. 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? Blastox will not be applied to the final excavated grade prior to placement of the fabric and backfill materials. • 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? 8 Blastox will be delivered in 3,000 lb Supersacks which will be stored near the job trailer under plastic. One supersack at a time will be transported to the section of bank being worked on at that time, and applied using the excavator bucket as a spreading spoon and then immediately mixed into the soil in place. The supersack will remain at the top of the bank on the timber mats. • 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. Blastox will be applied using the excavator bucket and then immediately mixed into the soil in place. Application timing will not be limited to dry conditions as light rain/sprinkles can be beneficial in the terms of dust reduction. Blastox application will not be conducted during heavy rain events. One section of bank will be stabilized, excavated, and covered with fabric at a time in order to reduce the “open” surface area. Sections will be the approximate width of the filter fabric roll. • 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. The off-site transportation and disposal of the metals-impacted soil is financially infeasible. • Was excavation of the soil, stockpiling, and treatment in an area away from the riverbank followed by disposal after treatment considered? Off-site disposal of this volume of impacted soil has been determined to be financially infeasible. This was evaluated at the time of site closure in 2011, and again in each of the 5-year reviews of the temporary solution in 2016 and 2021. 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? The prior filled raceway will need to be covered by an engineered barrier. The Plan Set will be modified to include the stockpile and its engineered risk reduction 9 barrier extending over a small portion of the southern end of the isolated wetland such that the entire previously filled portions of the raceway are covered. This is required in order to achieve a Permanent Solution under the MCP. • Is the stockpile engineered barrier permeable? Is an impermeable membrane not required because the soil is being treated with Blastox? An impermeable barrier is not required because the relocated soil is being treated with Blastox. Percolation of precipitation is not considered a concern as the concentrations of metals in soil have been demonstrated not to leach metals in excess of the EPA land treatment concentrations. The stockpile will be covered with an engineered risk reduction barrier to prevent dermal contact with remaining underlying impacted soil. The Mirafi filter fabric is permeable to water. • 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? Yes. • 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? The stockpile cover is not impermeable and erosion controls will be in place between the stockpile and the parking lot to the south. • 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. It is not feasible for the final stockpile to be limited to existing dimensions. Given the relatively thin and linear configuration of the available stockpile area, on top of similarly impacted soils, it is not possible to add the proposed excavation volume to the existing stockpile footprint. In addition, in 2006 the Conservation Commission requested that the stockpile present at that time be lowered to reduce its visual impact, which was done. One of the design goals in this proposal was to increase the overall height of the stockpile as little as possible, based on the prior concerns. 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 10 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. The timber mats for this project will not be constructed from treated wood. • How does the lower area access road connect to the construction entrance? Across the top of the northern portions of the stockpile. • Where is the access road? The lower area maintenance road is located along the top of the relaxed slope, or top of levee, as shown on sheets C6.2, C6.3, and C6.4. The construction entrance is located oOff Riverside Drive as shown on sheets C4.1, C6.1 and C7.1. • Is the planned access road permanent or temporary? The lower area maintenance road is permanent with a gravel surface. The construction entrance off Riverside Drive is Ttemporary. • 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. The lower area maintenance road is not 36 feet wide - it is 12 feet wide. A 16- foot-wide log mat area is coincident with this maintenance road and temporarily extends four feet toward Riverside Drive so the tree crane can access the work area, and later so that the excavator and dump trucks can access the work area. A separate 16-foot-wide log mat area is shown on the Grading Plans C4.x on the Riverside Drive side of the maintenance access road. As shown on sheet C7.1, the construction entrance access road is 15 feet wide where it crosses into the Site property. • 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. The crane access and stabilization areas are defined on sheets C4.x. It is not possible to access the necessary areas of the site without crossing a portion 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: 11 Access Road • We would like additional details regarding the constructed 12’ wide access road. Is this a permanent or temporary disturbance? The lower area maintenance access road is proposed to be permanent to allow future access to the retaining wall and rip-rap below the 100-year flood elevation, and the turf mat areas above the 100-year flood elevation. Details of its construction are shown on sheets C8.x. The construction entrance near Riverside Drive is temporary. • Will compacted sublayers be removed? No.Yes. • Will there be other plantings or just seeding? Will this be installed with the intention of using it to access the area by foot or by vehicle in the future? The intention is to allow access by vehicle, such that repairs can be implemented in the future if necessary. This is a state-listed waste site and the implemented repairs are designed to last a long time, but in the event of necessary repairs in the future, vehicular access will be required and is therefore a component of this design. • If 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? Planting of shrubs or trees is not proposed in the lower area maintenance access road. • Once the remedial alternative has been implemented, will the planned construction entrance be restored? There are no plans to remove the construction entrance access off Riverside Drive at the end of the project. This area is outside the 100-foot section of the Riverfront Area and within the 200-foot Riverfront Area, and will 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? The post-excavation sampling is designed to record the concentration of metals remaining on the bank after excavation, not to demonstrate the effectiveness of the Blastox. The number of samples is sufficient to meet the above-stated goal. 12 • OTO would recommend that TCLP testing also be performed to confirm that the application has effectively stabilized the metals. OHI completed a bench-scale pilot test with Blastox on the stabilization process using representative Site soil. OHI collected several composite surface soil samples from a location near the center of the levee and submitted them to Blastox for the test. Bench test results indicate that the stabilization process will reduce the TCLP concentrations of metals from Site soil to below EPA land application standards (5 mg/L). TCLP bench test results were 0.19 mg/L for Chromium and 0.99 mg/L for Lead, both well below the EPA limit of 5 mg/L. A similar product and process were utilized in 2005 when metals-impacted soil from AOC-1 was stabilized prior to creating the stockpile in AOC-2. Prior groundwater and other sampling results from multiple sampling events have demonstrated that the metals at the Site are not leaching at levels that negatively impact groundwater or the Mill River. This was initially demonstrated in the 2011 Method 3 Risk Characterization (OTO) for the Site and later corroborated in the findings of the 2012 Method 3 Risk Characterization (OTO), 2016 Stage 1 Environmental Screening, 2017 Stage 1 Environmental Screening, 2017 RAM Completion Report (OHI), and most-recent 2017 collocation sediment sampling. These efforts have demonstrated that a condition of No Significant Risk to the environment exists for Mill River surface water, sediment, terrestrial habitat/uplands, and floodplain soils at the Site, thus completing the Human and Environmental Risk Characterizations for the Site. Engineered Barriers • What are the planned limits of the engineered barrier(s)? There are several types of engineered barriers planned. The extent of the risk reduction barrier types is shown on sheets C5.x and are differentiated by color. • 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? Saplings will not be planted in the geocell area as they will grow into trees which will eventually fall over and disrupt the bank. • Will the fabric under the rip-rack rock be considered an engineered barrier? The filter fabric is one component of the engineered risk reduction barrier that will include clean fill, loam and turf reinforcement geocell mat. 13 Fencing • As part of the requirements of the AUL (specifically related to arsenic), will the chain link fence need to be restored? A chain link fence will need to be in place for the AUL along the Mill River side of the stockpile from the VHI parking lot up to approximately MW-4 and from there down the bank to the top of the southern end of the new stone retaining wall. This fence will have “No Trespassing“ signs in order to keep the public from entering the fenced areas west of the Cutlery Building and VHI parking lots. This will maintain consistency between the existing AULs in those areas, and the new AUL on this upper portion of the Site. 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. OHI recommends post-construction monitoring quarterly for one year, semi- annually for two years and then annual thereafter to coincide with the Annual LSP AUL Inspections which will continue indefinitely. Monitoring to be conducted by a Licensed Site Professional (LSP). • 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. Correct. NHESP determined there would be no take. There is no plan to implement temperature monitoring based upon the evaluation of shading and normal river flow in this area. • 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. 14 There is no water quality monitoring included in this project. The objective of the remedy is to reduce erosion into the river, which inherently is expected to improve water quality. • 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 and coverage of the canopy in areas where practicable and where the plantings do not interfere with engineered barriers. See responses above to the same comments. 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. The isolated wetland is not a state BVW, and replication is not required under the City Ordinance. 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. Large areas of the project area will not be unvegetated for a substantial period of time so dust monitoring is not required. After each subsection is completed, removed soil will be stabilized using Blastox and added to the Stockpile. Each relaxed bank section will be covered with Mirafi geotextile fabric as soon as the final grades are achieved. Then excavation will move to the next section. Dust control is included in the Site Health & Safety Plan. OTO STATEMENTS REGARDING THE LIMITED PROJECT STANDARD The Applicant notes that OTO presented the following statements in its letter regarding the 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 2016 and 2021 Periodic Reviews of the Temporary Solution for Area of Concern (AOC)-2 and 15 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” [emphasis added]. “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.”