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Response-to-comments-Final-6-3-19.pdfEnvironmental Planning Associates Specializing in Land Use & Zoning, Wetland Permitting & Septic System Design P.O. Box 351 413-665-7903 South Deerfield, MA 01373-0351 (866) 318-2770 (fax) e-mail: enplan@comcast.net June 4, 2019 Northampton Conservation Commission City Hall 210 Main Street, Room 11 Northampton, MA 01060 Re: Coles Meadow Road Camposeo Notice of Intent MA DEP File #: 246-0729 Dear Commissioners and Sarah LaValley: Enclosed please find revised plans submitted in support of the above-referenced Notice of Intent. We have revised the Plans and supporting documents pursuant to Sarah LaValley's April 30 comments. We provide additional information on several subjects. Vehicle turnout The proposed driveway is located on a part of the property not entirely occupied by wetland. A driveway in the middle of the property would disturb much more wetland area. A straight line, single lane driveway disturbs half as much wetland than a two lane driveway. However, single lane driveways inherently compromise motor vehicle and pedestrian safety. When two vehicles use the single lane driveway simultaneously, and approach each other head on, one of the two vehicles has to yield and back up. For safety reasons, the proposed driveway includes a “vehicle turnout” area. The proposed turnout allows a passenger or emergency vehicle entering the driveway from the street to avoid having to back out on to the street when a second oncoming vehicle is encountered exiting the property. The turnout area also allows a passenger vehicle or emergency vehicle leaving the dwelling and travelling west, from having to back up 510 feet, to the curved area at the eastern part of the driveway. The original plan submitted to Sarah Lavalley in February, proposed a second turnout in the buffer zone. This current plan moved that second (eastern) turnout completely out of the 100 foot buffer zone. Wetland and Buffer zone disturbance calculations The wetland and buffer zone disturbance calculations include the areas up to the silt fences. The silt fence on the north side of the driveway is located on the adjacent property. Accordingly, this portion of disturbance area was included in the numerator of the disturbance calculations. However, the wetland and buffer zone area calculations do not include any of the adjacent parcel 08-004 in the calculations of total wetland on the property. The abutting owner, Chuong Dinh, has given permission for temporary erosion control to be placed on his property. To further assist, we have enclosed an 11 x 17 colorized version of the plan view, delimiting the areas included in the disturbance calculations. No areas within 100 feet of the wetland situated on the City owned property to the east, will be disturbed. Wetland Replication The Massachusetts wetland regulations acknowledge that wetlands provide the following ecological and environmental values: ▪ protect public or private water supply ▪ groundwater recharge ▪ flood control and storm damage prevention ▪ pollution prevention ▪ fisheries and wildlife habitat The wetland on this property is significant for all of the values listed except groundwater recharge and fisheries habitat. The silt loam soil layer in the upper soil horizon prevents infiltration of surface water into the groundwater system. The proposed 1:1 wetland replication provides all of the functions and values provided by the adjacent bordering vegetated wetland. By slowing surface water flow from the property, the replication provides flood control, protects water supply, and prevents pollution. The replication enhances wildlife habitat by providing a diverse community of herbaceous plants, combined with the woody silky dogwood saplings. The Replication Plan meets the parameters of the Massachusetts DEP Guidance. An annotated version of the DEP Guidance Replication Checklist — Appendix 3 is enclosed. The annotations refer to the relevant parts of the Wetland Replication Plan. Tree removal in wetland replication area In this case, retention of mature trees would undermine the success of the wetland replication. Mature trees are evapotranspiring water from the ground to the atmosphere. The replacement of the mature trees with herbaceous plants and woody saplings will reduce the evapotranspiration rate, and facilitate water retention within the upper soil stratum. Soil saturation slows down the process of leaf litter decay. The slow organic decay elevates the organic content within the upper soil stratum. Soil with higher organic content retains more water and for longer duration, than mineral soil. The accumulation of organic matter within the soil profile is the key feature of any vegetated wetland because the organic matter detains water and sequesters pollutants. Very truly yours, Peter LaBarbera Enclosures: Design Plans Disturbance calculation polygons Replication Plan Field Data Sheets cc: Jerome and Susan Camposeo Adam Costa, Esq. MA DEP (WERO) Appendix 3. Replication Checklist A. Sequencing (See Section 1.3 for further guidance) 1. The Notice of Intent should include the following information:  Narrative on avoidance of wetland Impacts. [Wetland Replication Plan, Page 1, ¶ 1]  Narrative and plans showing minimization of wetland impacts. [Residential Development Plan Pages 1-3]  Narrative/drawings of alternative replication designs to ensure success.  Carefully designed replication plans with identified goals for unavoidable impacts. . [Residential Development Plan Pages 1-3] B. Elements of a Complete Replication Plan (See Section 2.3 for further guidance) 1. The application should include the following general information:  Narrative description of the existing and proposed wetland;  A site location map (such as a USGS locus) of existing and proposed wetlands; [Residential Development Plan, Page 1]  A 1”=10’ to 1” = 40’ plan including easily identifiable landmarks (e.g. surveyed flag locations, benchmarks, or structures), contour lines at 1-foot intervals, and locations of soil test pits and vegetation plots. A Professional Land Surveyor (PLS) and/or a Registered Professional Engineer (PE) should stamp plans. [Residential Development Plan, Page 1]  Grading should demonstrate elevation differences for different vegetation classes (forested, shrub, herbaceous, open water); [Grading plan contained on Pages 1 and 3 of the Residential Development Plan. The proposed wetland replication area is a topographically flat, semi-forested area adjacent to a flat semi-forested vegetated wetland]  Surface area calculations demonstrating a minimum 1:1 replacement to impact ratio (consider greater than 1:1 to ensure the success of at least 1:1). Do not count side slopes as part of the replication area; [Residential Development Plan, Pages 1 & 3]  Cross-sections of subsurface soil types, depths and locations, 100-year floodplain using both horizontal and vertical scale, existing and predicted high and low groundwater elevation, perched water conditions and other indicators of hydrology. Indicate cross- section locations on plan view; [Residential Development Plan Pages 1 & 3; Wetland Replication Report] 2. Hydrology – The narrative and plans should include the following:  The expected seasonal depth, duration, and timing of both inundation and saturation must be established for the existing wetland and for each of the proposed vegetation class in the mitigation area. [Wetland Replication Plan, Page 2 ¶ 3]  Evidence of soil including free water in a soil test hole, soil color, saturated soil or oxidized rhizospheres. [Wetland Replication Plan, §§ Hydrology and Soils, Pages 1- 4 ¶ 6]  In addition, the inputs and outputs in the water budget should be described. Ideally, replication areas should not depend on precipitation and sheet runoff flow only, but must have a seasonal source of groundwater and should have a surface water source as well. Perched wetlands may be established without these latter inputs, but monitoring wells or piezometers should demonstrate that runoff and precipitation inputs would exceed infiltration rates into the summer. [Wetland Replication Plan, Page 4 ¶1 ]  Demonstration that groundwater and surface water will have unrestricted hydraulic connections to the replication area; [Wetland Replication Plan, Pages 3-4]  Only the flood storage that the existing BVW provides should be designed in the replication areas; [Wetland Replication Plan, Page 4 ¶ 3] 3. Soils- the narratives and plans should include the following information:  Test pits of translocated soils including horizons, characteristics such as texture, organic matter, Munsell hue, value and chroma, consistence and evidence of hydrologic influence, e.g. mottles (frequency and color), gleying, and root depth; [Wetland Replication Plan, Pages 2-3]  Replication areas should have a minimum of 6-12” of A- Horizon soil. If used, soil amendments for the A-Horizon consist of equal volumes of organic and mineral materials. No woodchips should be used, and organic material should be well or partially decomposed. [Wetland Replication Plan, Page 4 ¶ 3]  Enough A and B-Horizon material (or A over a suitable composition of the C horizon) should be provided to create a suitable rooting medium, and to approximate the conditions at the nearest undisturbed existing wetland. Consistency should be loose to friable and texture should be loamy sand to silt loam. [Wetland Replication Plan, Pages 3-4]  Although not required, use of Redox and pH Meters in the replication area and adjacent wetlands may aid in replication success. Seek guidance of a professional experienced in this testing.  A detailed schedule for collection, stockpiling and placement of soils, including a discussion of techniques used to prevent the drying out and contamination of hydric soils. [Wetland Replication Plan, Page 6, # 2.]  Confirmation that invasive species listed in Section 2.3.3 are not present in the vicinity of the soil to be translocated. [No invasive species were noted in the replication area, which will be the source of any translocated soils.]  If soil amendments will be brought from off-site, a description of the source, preparation and placement should be included. [No soil amendments will need to be imported from off-site]  Discussion of a method to ensure appropriate compaction levels and the final consistency and texture of mitigation soils, by horizon. [Wetland Replication Plan, Page 6, # 6.]  Survey of finished elevations during construction should be conducted frequently and a proposed schedule included. [Wetland Replication Plan, Page 7,Replication Construction Monitoring.]  Discussion of post-construction soil characteristics such as horizons, depths, texture, organic matter, Munsell hue, value and chroma, consistence and evidence of hydrologic influence, e.g. mottles (frequency and color), gleying, percent gravel and rock, and root depth; . [Wetland Replication Plan, §§ Hydrology and Soils, Pages 1- 4] 4. Vegetation- narratives and plans should include the following information:  The dominant plants in each layer of the existing and proposed wetland and the relative cover and wetland indicator status for each vegetative layer proposed (herbaceous, shrub, sapling, tree and climbing woody vine); See Field Data Sheets 1 (Upland), 2 (Wetland), 3 (Upland) & 4 (Wetland) located in replication area and adjacent wetland, respectively.  Transplantation techniques including maintenance of viability of seeds, rootstock and plants during transplantation. Shrubs should be planted 8-10” on center and trees should be planted 10-15’ on center unless otherwise recommended by a nursery or wetland professional. [Replication Plan does not call for transplantation; seeds are presumed viable due to their origin at an established wetland plant nursery; Shrubs planted as shown on Plan View and Detail sheets.]  Consideration should be given to leaving mature trees on hummocks for shading if they are facultative or wetter. [Wetland Replication Plan, Page 3, ¶3 ]  A detailed description of sources of off-site plant material, species list, and methods to be used for planting. [Wetland Replication Plan, Pages 7-8]  Schedule for planting (at the beginning or end of the growing season - before the first frost). Check each species for ideal planting times. See Appendix 2 for growing seasons.  Wetland vegetation expected after two growing seasons as well as predicted community after natural succession. [Expected plant community that of seed mix and planting of silky dogwood saplings]  Contingency plan in case of mortality of vegetation, invasive species, complete failure, inadequate size, etc. [Wetland Replication Plan, Page 7]  For larger projects micro topography should be shown in cross-sections including number of mounds and pools if proposed to replicate existing conditions. 5. Wildlife Habitat  Documentation of the Estimated Habitat Map of State-Listed Rare Wetlands Wildlife findings for the site should be included. [This area is not mapped for any designated rare species.]  For projects impacting the wildlife habitat functions of BVW’s, wildlife habitat characteristics of the site, including vernal pools, should be described and replicated. Design should include diversity of vegetation structure and composition, and of hydrological conditions. Credentials of wildlife habitat specialist should be included. [This area is not mapped for any designated rare species.] 6. Stormwater Management  Created wetlands for stormwater “best management practices” shall not be given credit as replication areas; [This proposed wetland replication area is not serving as a stormwater detention or retention basin.] 7. Erosion Control- narratives and plans should include the following:  An erosion control plan that details stabilization techniques during construction and a contingency plan for construction and post- construction periods.  A commitment to remove erosion control measures once the site is stabilized and following approval by the issuing authority.  Embankment slopes should be no greater than 2H: 1V unless structural stabilization. C. Considerations During Construction (See Section 3.0 for further guidance)  The erosion and sedimentation control plan must be implemented. [Erosion control consists of silt fence, which will be inspected for proper installation by Environmental Planning Associates.]  The wetlands and replication area should be reflagged prior to construction start date if the flags placed during permitting are not clearly visible.  A construction schedule listing the sequence of events for replication construction (preferably before work in the existing wetland); [Wetland Replication Plan, Pages 5-6]  A project monitor with a minimum 5 years experience should be identified; [Environmental Planning Associates] D. Monitoring Plan (See Section 6.0 for further guidance)  A plan to monitor the construction and subsequent growth for at least two years or until the 75% criteria is met following construction should be included (See Appendix 3 for example checklist). Include contingency plan in the event that the replication area does not meet the 75% reestablishment standard.  Colored photographs from established reference points should be included with each monitoring report. [Environmental Planning Associates]  Plan must include inspection of embankments to ensure that they are stable, properly vegetated and constructed as designed. [The sides of the wetland replication area will be regraded at a relatively shallow 5:1 slope, which poses a very low risk of failure; Subgrade inspection will be conducted by Environmental Planning Associates when: ▪ the replication area is excavated ▪ when grading is complete ▪ after silky dogwood saplings are planted and seed mix applied]