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HomeMy WebLinkAbout1986-08-18 Statement of Environmental Impact ;)ESIGN ENGINEERS ASSOC i1 . P. 0. BOX 516 NORTH ANDOVER, MA 01845 May 1 , 1986 STATEMENT-OF ENVIRONMENTAL IMPACT NOTE: Paragraph identification corresponds to that of Paragraph III B. 5 of the Rules. A. See also "Plan of Proposed Site Grading, Environmental Impact and Erosion/Sedimentation Control" and "Definitive Plans-Construction", by Design Engineers Assoc . P.C. , attached. B. Physical Environment 1 . The existing general physical conditions of the proposed subdivision site are those of a wooded tract of land on rolling hills and valleys. Topographic elevations range from approximately 250 feet above sea level along the eastern property on the lower slopes of Bruin Hill to 138 feet above sea level along the lowlands bordering a portion of ' the southern and western property lines. The roadway and dwelling locations are between sea level elevations of approximately 140 feet to 180 feet. Vegetation is predominantly soft and hardwood trees of varying types and sizes, and the associated ground cover usually found in wooded areas in northeastern United States . There are no unusual geologic, scenic or historic features to the site. A trail, crosses the western portion of the property and neither extends through the entire parcel nor connects to trails on parcels. There are no open space links on the property. The indigenous wildlife is minimal , due probably to adjacent development, and consists mostly of small mammals and birds indigenous to New England. 2 . The subdivision is designed to maintain the overall topography of the area within the confines of local development regulations. The majority of the perimeter of the property will remain natural after development. Obviously, all development has an adverse effect on natural ecology. The proposed subdivision design strives to minimize this effect. Additionally, previous development has lessened this effect due to its impact on the surrounding natural environment. 3 . The project consists of the development of approximately twenty acres of land into a fifteen lot residential subdivision. Related construction includes that of: a. Approximately one thousand two hundred fifty feet of paved way, two cul-de-sacs and road slope grading and stabilization. -1- b. Storm sewer and municipal water main within the subdivision. c. Individual subsurface disposal systems for each lot. d. Underground' electrical and telephone service. ee Fifteen single family dwellings and related services, drives and lot development. C. Surface, Water and Soils 1 . During and immediately after rainfall, related run-off sheet flows from the proposed subdivision property and upland watershed properties across the property to two general outfallss a. Sheet flow to the low area along the southern n, property line. b. Sheet flow to the low area along the western property line. During rainfall, temporary minor ponding due+ to topographic depressions and ihtermi.tten stream flow due to natural erosion may exist on the subdivision property. However, as substantiated by the preliminary findings of the North Andover Conservation Commission, no wetlands, as defined by State regulations exist on the property except along the western and southern property lines. 2 . Prior to, and during construction of the subdivision, and until stabilization of disturbed areas and paving are completed, staked haybales will be maintained: a. Approximately twenty-five feet from the toe of slope on the northern side of the roadway from station --O+SO to station -3+SO and on the southern side of the roadway from station 2+00 to station 6+00 . b. At all headwalls. c. Around all catch basins. Unstabilized slopes will be matted with hay during seasons not conducive to germination. The base of the detention areas will be excavated one foot deeper' than finished grade and will act as a sedimentation basin during construction. Road slopes will be foamed immediately after grading. Cutting and filling operations using on-site materials will be completed simultaneously. Easement areas will be stablized immediately upon completion of scheduled work within the easement. Upon completion of the drainage system , paving of the -2- u roadway and laI dzation of disturbed je 6 silt and debris will, be removed from all drainage structures , pipes' and- spillways, and the base of the retention area will be graded and stabilized. Although every practical, attempt will be made to minimize exposing the entire roadway and slopes, this would be the most severe - unprotected' condition. In this case, approximately two acres would be cleared at one time . Based on previous experience, haybale erosion checks would suffice in controlling siltation of undisturbed areas. Implementation of the other measures in conjunction with haybales insure that this will be the case . 3 . All disturbed areas will be either paved or stabilized with grasses. All key erosion points, that is those immediately adjacent to headwalls, will be rip-rapped to eliminate erosion. Additionally: a. Flooding and pondi.ng is not anticipated on site. The detention areas and drainage system are designed to minimize off-site flooding or ponding. b. The proposed surface drainage system contains the majority of the run-off from the site and directs it to the hydraulically controlled environment of ' the detention area. That run-off not directed to the detention areas is directed to its natural watershed. The detention areas are 'designed to contain the increase in run-off volume, due to development for a one hundred years frequency storm event, and to outfall at a rate equal to or lower than that presently experienced. c. All disturbed areas will be either paved, rip-rapped or stabilized with grasses. d. Roadway design and proposed dwelling locations attempt to maximize the protection of existing vegetation. The majority of the perimeter of the property will remain undisturbed. e. Within the confines of the Rules, the subdivision' s proposed grades and existing topography are blended to preserve natural aesthetics. Road grades are minimal and well within the regulations. Cuts and fills for the road and lot development approximately balance. Grading is confined to roadway and lot development with houses located as close to the roadway as practical , thus minimizing changes in topography in the rear of the lots. f. There are no proposed alterations of shore lines, marshes or seasonal wet areas on the subdivision site* The detention areas at the two headwalls, outfall to their adjacent wetlands and are designed to blend with the existing topography and require minimal, upkeep. -3- ;s depicted on the ❑ef, Jt, 've Plans the two off road drains will be easemented to the Town. Right of Way easements to two abutters will also be granted. h. As depicted on sheets Two and Three of the "Definitive Plans-Construction" by Design Engineers Assoc. P.C. and discussed in the preceding section of this report concerning drainage, both existing and proposed drainage outfalls to two watersheds. The peak run-off rates and volumes outflowing the property both before and after development are discussed in the drainage analysis. As demonstrated in that analysis, run-off volumes are increased slightly after development, however run-off rates are not. In the detention areas accumulated run-off will remain stored until it either flows at varying rates to the existing wetlands, percolates into the ground-water table or evaporates into the atmosphere. 4 . The lots at Turner Estates will be serviced by individual subsurface disposal systems designed to meet or exceed all state and local governing statutes . Minimal impact on surface water , ground water , soils and vegetation is anticipated. D. Subsurface Conditions 1-3 . As stated above, and listed on sheet Four of the Definitive Plans, all of the lots have been tested for subsurface disposal system designs. In general , the soils have been established as more than adequate in supporting such designs. The parent soil encountered was a sandy till tending towards granular and percolation rates averaged ten minutes per inch. E. Town Services 1 . Turner Estates terminates with two cul-de-sacs and has one access to a Town road, that is Bridges Lane. Traffic within the subdivision is self contained. The maximum traffic increase to Bridges Lane is anticipated at thirty vehicles. Of these , not more than fifteen, and more probably, ten cars will exit the subdivision at any one time . Bridges Lane is a relatively straight road, in good condition. Bridges Lane slopes downward to Foster Street, a distance of approximately three thousand three hundred feet at an overall slope of approximately five percent and is intersected by Vest Way approximately five hundred feet from Turner Estates , prior to its termination at Foster Street. Vest Way runs approximately parallel to Bridges Lane and also terminates at Foster Street. 2 . Each dwelling will service the parking associated with it. Garages will service the two vehicles belonging to the dwelling. Driveways and turn-grounds will accomodate visiting vehicles. 3 . The two cul-de-sacs at Turner Estates will minimize the -4- effect on Po : ie nd fire protection,, a. �l force vehicles to travel at residential speed limits. The limited access to, the subdivision provides security to its inhabitants. The subdivision is designed with municipal water and fire hydrants spaced at less than five hundred feet throughout. 4 . The project utilizes municipal water. All services will be installed to front property lines. Each builder will be required to connect these services to the individual dwelling. As all materials used will. be new, meeting Town specifications and tested to insure proper installation, no increased demand on the Public Works Department is expected. Water use assessments should offset any increase in cost to the Department. 5 . The project proposes the addition of fifteen families to the Town population. With this will be an indeterminable increase in the demand for Town educational services. Also associated with the population increase will be an increase in revenue to the Town through property taxes. The dwellings will have a value and will yield tax revenues well in excess of the Town' s average dwelling. As the majority of tax dollars are spent on education, the net effect on the school system by the subdivision will be positive. 6 . The project will increase the demand on Town water by that of fifteen families, or ' approximately fifteen thousand gallons per day. F. General Impact The Turner Estates subdivision is located in an environmentally non-intensive area . There are no wetlands on the site► no unique vegetative cover, and minimal wildlife. The latter is due in part to the fact that the proposed subdivision is in direct proximity to a previously developed subdivision; The Bridges. Development of Turner Estates is harmonious with the surrounding development. The subsurface disposal systems should pose no threat to the ground water aquifer and the use of municipal water insures that the aquifer will not be drawn down by the development. Roadway design optimizes security, traffic control and fire protection. Finally, the proposed dwellings will add needed revenue to the Town through its tax structure and service fees. The development of Turner Estates has an additional positive influence on the surrounding natural environment. The tract of land of which Turner Estates is a small part► stretches from Salem Street to Foster and Winter Streets. An agreement between the owners of this parcel and the Essex County' Greenbelt provides for development of this fifteen acres subdivision and one other subdivision within the tract of land. The agreement further stipulates that the remainder of the tract, over one hundred acres will be deeded to the Greenbelt and remain undeveloped conservation wilderness.