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HomeMy WebLinkAbout1998-04-10 Response Comments SPR i H ISTIAN EN & SERGI, INC. PROFESSIONAL ENGINEERS AND LAND SURVEYORS 160 SUMMER STREET HAVERM.L, MASSACHUSETT3 01831)•6318 (478)373-0314 FAX; (97$)372.34450 March 2, 1998 John C Oliessia 1. f;, Cofer & Colanlorn o, Inc. � � �� >� � 101 Accord Park Drive Norwell, MA 02.0 1-1685 LPLANNING R Re-, Site Plate; Lot 1- B-1 Orchard Ill Road,North Andover Engineering review Dear 1r- Clicssla, Enclosed is a copy of the revised--Site Plan for the above referenced project for your review- Revisions have been made to the plan based upon the review by'Town Planner Kathleen Colwell arid the Technical review Committee. The revisions made to the plan include, I, A Drainage System Summary table has been added to the p1wi- This table includes all of the design elevations and specifications for the proposed drainage system. , A proposed lirinit of work line.has been added to the plan. I Wood fence enclosures have been indicated around the t w dumpsterlcompactor areas. 4. The location of the proposed undergToulad utilities has been indicated. . The location of the proposed driveway to the abutting Lot 1- A, and the distance- between the two proposed driveways, have been added to the plan. 6. Additional specifications for the roof drainage has been added to the plan- Please contact us if you have any questions regarding this tnnatter. Truly Yours, I' ' ' - Christiansen c.c. 4o n Manner Kathleen Colwell Steve Webster,Dutton& Garfield, Irc CHRISTIANSEN St SERGI, INC�. PROFESSIONAL ENGINEERS AND LAND SURVEYORS 160SUMMERS THE ET HAVERH;1;1,,L, MASSACHt,JSM�SCJ]830-6318 (978)373-0310 FAK (978) 372,39,60 March 20, 1998 .......... Mr. Jolui C Chessia Coler & Colantonio, Inc, 10 1 Accord Park Drive No�rwell, MA 020,61-1685 Re: bite Plan. Lot 1-213-1 Orchard HE Road, North Ajidover Engineering Review Dear Mr,. Chessia: Enclosed is a copy of the,revised Site Plan for the above referenced projt0t for your review ., Revisions have been made tug the plan based uplon your review comments and the conunents of the Planning,Board., The,follow ing is a response to your March 11:, 1998 letter of review. Ea,ch of your conunents is listed in italics. Our response to each comment inunediately follows, 1. Section 8.,3) 5) e) ff.) 77iere is no 7-c, Registereti Land Surveyor. ference it) a plan ancibr:wed by a A copy of the ANR,plan, that created the subject lot is attached, An easement plat), i,s being prepared to create the new roadway turnaround easement and the utility easement between Lots 1-2A and 1-21 -1. A coply of the easement plan will be sent to you upon its completion, 2. Section 8-3), 5) e) iv.,) Me plan indicates the cul de sac easement., It I's unclem-ivhw h proposed a.v the final road vqy k�yout. At their March 17, 1998 meeting,the Planning,Board requested that the pavement in Orcliard Hill Road be extended to provide at least 150 feet of paved frontage for the lot, The Site Plan has been revised to indicate that the pavement will be extended to provide this ftontage, and that a new turnaround casement will, be created around the relocated cul-de-sac- 3". Section 8.-�) 5j e.) vii.) �ee di-Wricige issues below. No response required. 4. , eelion &3) .) e.) jx-) Building elevations have not been submitted io us with this Purr set. It is unclear ifthe Planning Board received this information. 4 The required building elevation draws V have been subn tied to Town Planner Kathleen Colwell- J. Section 8.3) 5.) e. x.) The Building Inspector should review the plans for DA compliance. No response required. b. Section 8.3) 5J e.) xi.) No wedands are ind c:aled on the plan. North Andover Conservation Agenis Mehael Howard and Richelle Martin have performed a site inspection and confirmed that the work proposed for the project does not fall within 100 feet of any areas subject to protection under the Wetlands Protection Act or the North. Andover Wetlands Protection Bylaw, 7. Section 8.3) 5 e) xrri) A detail should be included or the handicap access ramp. A typical handicap ramp detail has been added to Sheet 2 of 2, 8. Section 8.3) 5.) e.) xv.) the plan dries not indic:ale existing Bees It is unclear if the laradscapepkrn conforms to Ybwn requiremenO. We nose that there are no plantings along the northern properly line adjacent to the,frontage road. All of the existing trees within the limit of work indicated on the plan will be removed_ No trees will be removed from the areas beyond the indicated limit of work- Additional plantings along tine roadway will be added to the plan if the Planning Board decides it is necessary. 9. Section 8.3) 5.) e.) vn.) A detail of the lighting fixture io he used should be included in the plan set. Lighting isnits do not show connections to failiile s. typical ligbting fixture detail has been added to Sheet 2 of 2. The proposed electric lines connecting the light poles to the buildhig have been added to the Site Plan. 10, Seelion 83) 5) e. xrci) It is assumed that a "U"indicates cable utilities. Yhiy line is on Lol 1- A and will require an easement. 15 foot wide utility Easement running along the lot lute between the two lots has been added to the Site Plan- The required Easement Plan is being prepared, and a copy of it will be serif to you upon completion. 11. It is our understanding that Sections 5.3) 5 e) x?x, xx, xxii, xxifi, al-e typically r'evre3 md by 7bwn Staff. o response required, Drainage roses. 12, Ae I 'flared end discharges on to abrrtfing property at apoint. nis area dries Trot currently appear to recy,-jve concentrated ow. The design uOicales this pipe would unly discharge in storms greater than a 2 yr, 2 4 hoar evert. The owner of the abuttiatg lot is George R- Barker, Jr-, who recently sold Lot 1- B-1 to the applicants and is aware of the drainage outfall and its potential for flow during extreme Tanoff evc ts, 1t should a]so be noted that the outUl will be adjacent to a natural drainage path located just over the boundary on the Barber property- This drainage path collects a high volume of runoff from the large hill to the east/southeast.(see the drainage area maps submitted with the Hydrologic Analysis for the project . The concentrated flow that will be released from the detention area during extreme r-unofr events will not be significant compared to the runoff rates produced by the remainder of the watershed. 13. The dejentionlinfiftr'ation basin b&Uorn is,shown to be at elevation 102. ne groundwater level in the lest pit data is estimated as 101,5. The detentionlinfi tration basin was designed so that the bottom elevation was approximately at existing grade (elevation l 0 .0)- This would allow far sufficient separation over the estimated seasonal high water table depth of30 inches. The topographic constraints of the site would not allow for a higher elevation- We needed to collect as much of the site runoff as possible and direct it into the detentionlinfiltration basin. The elevations of the existing roadway, adjacent parking area, and the proposed landing docks dictated the maximum elevation at the bottom of the basin. W e we understand that the separation between the bottorn of the basis and the estimated seasonal high water table may be less than two feet at the high end of the basin,we would like to Mote that the estimated seasonal high water table identified in the test pit is based on redoxomorpliic features in the soil that indicate zones of temporwy saturation- The identification of the estimated seasonal high water table in the test pit was based on the Title 5 definition of estimated seasonal high water-table used in subsurface disposal system design. No actual groundwater was encountered in the test pit,which was dug to a depth of most 13 feet. While we appreciate that COler & olanto'tio, xc. i commends a separation of two Feet between groundwater and the base of leaching areas, we are unaware of any such requirements for work in the Town of North Andover_ If sucb a requirement did exist, it is lugbly likely that we would comply witb the two foot separation if'any defftfition other than the Title 5 definition of estimated seasonal Wgh water table were to be rased_ 14, Test pif data or•Infiltration Area 3 should be provided. The location OP#2, the test pit performed for the leaching facility on Lot J- 2A, has been added to the plan_ This test pit is adjacent to proposed Jnfiltration Area##3, A copy of the soil log for the test pit, as performed by Steen J. D'Urso, Registered Sanitarian, is attached_ The soil log indicates that the estimated seasonal high water table its the area is at elevation 91-8 feet, which is greater than two feet below the bottom of the leaching area. 1.5. Additional spoi gra*s should be indicated the parking lot to show pavement slopes. Additional proposed spot elevations, along with typical parking area and driveway cross section slopes, have been added to the Site Flan. 16 Storm drainpipe calc`uialions, including,inlet grate capacity should be provided. The Drainage System Sunimmy included on the Site Plan has been revisal to include the flowing full capacities of the pipes in the storm drainage syst , The,catch basin inlets were assurned to have a capacity of approximately 1 efs without ponding_ Thy only two catch basins which will be subjected to rates above I cfs are catch basins #9 and 10 duTing the 100 year event. These two basim are to be iiistalled in sump locations where runoff'can pond to depths of 2.0 feet and 1,0 feet, respectively, before any overflow will occur_ At these depths of ponding, the catch basin grate capacities will increase substantially. Should these areas overflow, however, the runoff would flow towards catch basins 7 and S. and should these overflow, the runoff would overtop the curb and flow into the detention area anyway. It should be noted that no separate storm drain pipe calculations were performed. We are una-ware of any such requirement for Site Plan review in the Town of North Andover_ As part of the design process,the pipes are sized based on the results of the Hydrologic Analysis_ On a small site such as this, catch basin Placement is usually based on grading requirements rather than runoff'capacity requirements_ Calculations are not required to determine if the inlet grate capacities are sufficient. This can be determined intuitively if the- contributing i i i areas are small, of it can be inferred from the results of the Hydrologic Analysis. To perform the additional calculations would be a waste of the applicants' money and the engineer's and rtvi�wer`s time_ 17. Me location of the .septic system on the abutting property.should be indicaled. The location of the septic system has been added to the Site Plain. 18, 1J71tration valves Frscdappear reacvanable based on our review of test Pit daea and NRCS igformauon. U,expedite the revre sng process, eve recommend that the applicant describe the basis axed far infiltration rates. The 4"orifice in the oullel structure will be subject to clog in , We recommend the structure be mudijied to provide priwec:lion from Clogging. The in itration rates used were Eased on the mhiimum infiltration Fates listed for the appropriate S_ _ . soil groups as listed in the Metropolitan aAi ngon Council of Govennnents° " OI ROLLf 'G URBAN RUNOFF- A PFLA TICAL MANUAL FOR PLANNING AND DESIGNING URBAN BMP° " as supplied to us by Coles& Colantonio, Inc. during their review of the Site Plaii for the abutting lot. A copy of the table from the reference is attached. The 4 inch orifice in the outlet structure will be located I.7 #bet above the bottom of the basin. This should prevent the accumulation of debris that could clog the orifice. This type of outlet structure is necessary to control the low rags of discharge as rewired for this small development. The maintenance of the detentioiVinfiltration basin will become part of the routine landscaping and maintenance schedule for the facility. The aclihood of the 4" orifice becoming clogged when it is routinely inspected and only subject to Mows during extreme runoff events is very low. It should also be noted that should it become clogged, it will orAy serve to retain a higher volume of water in the basin_ The larger orifice above it will still be assailable for the higher flow fates. Please contact us if you have any questions regarding this matter. 44ry Truly , P1 p . Christiansen 0.0. Town Planner Kathleen Colwell #eve Webster, Dutton & Garfield, Inc.