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36_-251_letterAD 21 Maple Ridge Rd- general informationPART I: GENERAL INFORMATION Project Description The project site is located on the northerly side of Maple Ridge Road approximately 200' west of Florence Road (See Figure 1). The project consists of the construction of a single family dwelling within the 100' Buffer Zone of a Bordering Vegetated Wetland. The dwelling will be serviced by a subsurface sewage disposal system which will be greater than 50' from the wetland boundary, but within the 100' Buffer Zone. A bituminous concrete driveway will cross the Buffer Zone along an area previously prepared for such a use. The wetland consists of a long swale which channels surface water runoff along the easterly border of the subject property. The stormwater crosses under an existing gravel roadway/driveway through a 12" reinforced concrete culvert. The culvert was installed in the late 1980's to provide access to this lot in the Maple Ridge subdivision. Construction shall be limited to the 100' Buffer Zone. No wetland will be disturbed as part of this submittal. 7e. Filing, Fee The filing fee for this project has been determined to be $285.00. It consists of the construction of a single family dwelling, septic system, and driveway within the 100' buffer zone of a bordering vegetated wetland. The construction is a Category 2 project which requires a $250.00 filing fee. The additional $35 is a local filing fee payable to the City of Northampton. Of the total filing fee, $112.50 is submitted to the Commonwealth of Massachusetts with the remainder submitted to the City of Northampton Conservation Commission ($172.50). See a copy of the two filing fee checks, the Fee Calculation Worksheet, and the Fee Transmittal Form in Appendix 2. PART II: SITE DESCRIPTION A. Natural Features 1. Soils Figure 2 presents the soil survey for the subject site, completed by the U.S. Soil Conservation Service (taken from the Soil Survey of Hampshire County, Map 417). The soil type shown to be at this site is Paxton very stoney fine sandy loam (PcC). Paxton fine sandy loam is a deep and well drained soil. The permeability of this soil is moderate in the subsoil and slow to very slow in the substratum. The substratum is very firm, causing a high seasonally perched water table. Erosion potential of the Paxton soils is low to moderate. 2 The Soil Survey also indicated an area of Udorthents, which is an area that has been disturbed at some point in history. The soils in this area could range in permeability from slow to very rapid. Test pits excavated for soil evaluations and percolation tests found very coarse sandy soils near Maple Ridge Road, while excavations farther into the parcel (north of the wetland) confirmed the Paxton soils. 2. Vejaetation The vegetative canopy at this site is dominated by mature Red Maple. The remainder of the canopy includes Hemlock, White Pine, White Birch, and Red Oak. The shrub layer is dominated by Winterberry Holly and young Honey Locust. Sensitive Fern, Cinnamon Fern, and Soft Rush dominate the ground cover where sunlight can reach open areas of the site through the canopy. A vegetation list has been included in Table 1. 3. Flowing Water Bodies There are no flowing water bodies on this site. The drainage Swale carries stormwater westerly, but no definitive stream channel exists. 4. Boundaries of Resource Areas The resource area boundary was delineated in the field with blue surveyors flagging, numbered from W 1 to W8 on the westerly side of the RCP culvert and E 1 to E6 on the easterly side. The boundary of the Swale was determined based on vegetation and topography since the swales were man-made and most of the soils were disturbed. The Swale perimeter consists of well defined banks along the area closest to the proposed work. B. Man-made Features I. Drainage and Flood Control Facilities The wetland at this site is a direct result of the drainage system for the subdivision in which the subject parcel is located. Stormwater runoff from the north easterly side of the project is channeled, through man-made swales and concrete culverts, into a large detention basin. Collected stormwater is then released to an un -named stream down gradient of the site. The storm drainage system was constructed in the late 1980's. The existing 12" RCP culvert under the roadway/driveway on this parcel was installed as part of the original construction of the subdivision. 3 TABLE 1: Vegetation identified on subject parcel on Maple Ridge Road, Northampton, MA on April 30, 1996 by Pioneer Environmental. The Hydric Indicator Status (H.I.S.) for each species was obtained from the National List of Plant Species That Occur in Wetlands: 1988, Massachusetts. Common Name Scientific Name *H.I.S. **Abundance Red Maple Acer rubrum FAC 5 Honey Locust Gleditsia triacanthos FACU 3 White Birch Betula alba FACU 3 White Oak Quercus alba FACU 1 Eastern Hemlock Tsuga canadensis FACU 3 White Pine Pinus strobus FACU 3 Red Oak Quercus rubra FACU- 3 Silky Dogwood Cornus amomum FACW 2 Mountain Laurel Kalmia latifolia FACU 2 Speckled Alder Alms rugosa FACW+ 2 Swamp Rose Rosa palustris OBL 3 Cinnamon Fern Osmunda cinnamoma FACW 4 Sensitive Fern Onoclea sensibilis FACW 5 Christmas Fern Polystichum acrostichoides FACU 2 Soft Rush Juncus effusus FACW+ 4 Broom Sedge Carex scoparia FACW 3 Green Bulrush Scirpus atrovirens OBL 3 Broadleaf Cattail Typha latifolia OBL 3 * Hydric Indicator Status: See descriptions on next page ** See Abundance Key on next page :I INDICATOR CATEGORIES OBL (Obligate Wetland): Occur almost always (>99%) in wetlands under natural conditions. FACW (Facultative Wetland): Usually occur in wetlands (67%-99%), but occasionally are found in upland environments. FAC (Facultative): Equally likely to occur in wetlands or uplands (34%-66%). FACU (Facultative Upland): Usually occur in uplands (67%-990/o), but occasionally found in wetland environments. UPL (Obligate Upland): Occur almost always (>99%) in uplands under natural conditions in this region. May occur in wetlands in other regions of the country. A positive (+) or negative (-) sign is used with the facultative indicator categories to more specifically define the regional frequency of occurrence in wetlands. The positive sign indicates a frequency toward the higher end of the category (more frequently found in wetlands), and a negative sign indicates a frequency toward the lower end of the category (less frequently found in wetlands). ABUNDANCE KEY 5: Very abundant; the only dominant species of that vegetative layer for the subject area. 4: Moderately abundant; is a dominant species of that vegetative layer but may share the dominance with one or two other species. 3: Somewhat abundant; is not a dominant species but can be found throughout the subject area. 2: Uncommon; very few individuals scattered throughout the subject area. May occur in isolated clumps. 1: Rare; represented by a single individual or occurs in a very low density throughout the subject area. 2. Subsurface Sew a we Disposal Systems There are no existing subsurface sewage disposal systems located on the subject parcel. 3. Underground Utilities The only existing underground utilities at this site are a water service line and electric, telephone, and cable TV. These services have not been extended into the site beyond the front property line. I Roadways and Parking Areas There is no pavement on the subject parcel. An existing gravel roadway exists on the parcel. This roadway was installed as part of the subdivision construction and intended to be the driveway access to the building site on the lot. 5. Property Boundaries The corners of the subject parcel are all marked with iron pins. Property boundaries and dimensions have been shown on Drawing #98-025. PART III: WORK DESCRIPTION 1. Structures One single family home with a detached garage will be constructed within the buffer zone as shown on the Site Plan. The dwelling will have a 12 foot wide bituminous concrete driveway running from Maple Ridge Road to the proposed new structures. The proposed house location is approximately 50' from the wetland boundary at its closest point and the garage 65' at it closest point. 2. Drainage and Flood Control Facilities No new drainage or flood control structures are proposed under this submittal. 3. Subsurface Sewa a Dis osal S stems &Under ound Utilities The subsurface sewage disposal system to serve this dwelling shall be located greater than 50' from the wetland boundary, as required by Title 5. Due to unsuitable soil conditions on the northerly side of the wetland swale, the proposed leaching system must 6 be located near the road, approximately 200' from the dwelling. This was the only location on the parcel which would meet the minimum requirements of Title 5. Several test pits were excavated within the main portion of the lot north of the wetland, but all pits exhibited dense glacial till with a shallow, perched water table. Pits excavated at the southeasterly corner of the parcel found a sufficient depth of coarse sand and gravel and a seasonal high water table at a depth of 70", which will allow a leaching system to be installed which meets Title 5 requirements. However, in order to meet the setback requirements to the wetland, an easement onto the Maple Ridge Home Owners Association buffer strip land is required, as shown on the Site Plan. Preliminary discussions with representatives of the association have been favorable, pending approval by the municipal agencies involved (Conservation Commission and Board of Health). In order to reach the leaching system, a 4" PVC gravity sewer must be installed from the proposed 1500 gallon septic tank, to be located near the house site. The gravity sewer will follow the proposed driveway and cross over the existing 12" RCP culvert approximately 30" above the top of the culvert. This 4" gravity sewer will be heavy duty PVC (SDR 35) and will have watertight, rubber ring joints to prevent any leakage as it passes near the wetland. Except for one section which crosses under the driveway, it shall be laid beyond the edge of the driveway to protect it from traffic loads. The section crossing under the driveway will utilize a heavier grade of PVC (Sch.40) or cast iron. The 1500 gallon septic tank shall also be located more than 50' from the wetland boundary. The City of Northampton requires a setback of 75' for septic leaching systems from wetlands versus the 50' required by Title 5, however, there is no feasible location on this Parcel where we can meet the 75' setback requirement. The Northampton Board of Health and Conservation Commission must both approve this reduction in setback of the local regulations back to the Title 5 standard of 50'. A formal septic system design and application has been submitted to the Board of Heath for their consideration. Other underground utilities to be installed within the 100' Buffer Zone will be a water service and electric, telephone, and cable TV. These lines shall run parallel with the driveway and over the existing culvert. 4. Filling, Dredging and Excavating No wetland area shall be altered under this proposal. Excavation and grading shall be limited to the 100' Buffer Zone, as shown on the Site Plan. The grade of the existing driveway at the 12" RCP culvert must be raised by approximately 18" in order to provide sufficient cover over the proposed 4" gravity sewer. The proposed finished side slopes shall be at no greater than a 2:1 slope. The existing side slopes are poorly vegetated and do not contain a sufficient amount of top soil to sustain an adequate vegetative cover. To correct this problem, the side slopes nearest to the culvert inlet and outlet and above the wetland boundary will be re -graded, loamed, and seeded. Most of the trees and shrubs nearest to the culvert have grown in wild and are in poor condition. Many have been damaged by the severe snow and wind storms over the past two years. It is proposed that the existing vegetation along the proposed driveway be selectively pruned and replaced with heathy native species, both shrubs and saplings. 5. Compensatory Storage Areas This project does not involve the filling of any land within a Flood Zone (see Figure 3). 6. Restoration and Replication Areas No restoration or replacement of wetland is required or proposed under this submittal. PART IV: MITIGATING MEASURES 1. Inland Bordering Vegetated Wetland The resource area shall be protected by the installation of a geotextile siltation barrier installed as shown on the Site Plan. This siltation barrier shall also act as a Limit of Work line. After the driveway side slopes are loamed and seeded, hay mulch will be spread over the area to help prevent erosion. 2. Inland Land Subject to Flooding No Land Subject to Flooding shall be altered under this submittal. 3. 100 -Foot Buffer Zone of Bordering Vegetated Wetland Protection of the wetland areas adjacent to the construction site will be accomplished by the use of mandatory setback limits, erosion control barriers, and construction sequences. Once installed, the siltation barrier shall be considered the no disturbance limit. The siltation barrier/limit of work line shall be maintained until on-site soils are stabilized. Any stockpile of soil on the site will be located as far from the wetland as possible.