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HomeMy WebLinkAboutConsultant Review - 80 FLAGSHIP DRIVE 8/16/1995 COLE R & z COLANTON100 7 ENGINEERS AND SCIENTISTS August 16, 1995 Planning Board c/o Ms. Kathleen Bradley Colwell Town Planner Town of North Andover 120 Main Street North Andover, MA 01845 RE: Engineering Review 80 Flagship Drive Proposal No. 1-487 Dear Ms. Colwell: Coler & Colantonio, Inc. is pleased to provide you with this proposal to perform engineering services associated with the above project. It is our understanding that we are to review the plans and calculations for the above referenced commercial development in the Town of North Andover. Specifically, our review would cover stormwater runoff calculations and design. The plan would be reviewed under the Site Plan Review provisions of the Zoning By-Law. The plans would also be reviewed for conformance to standard engineering design standards. Included in this proposal is a Scope of Services which outlines the specific tasks to be performed, a listing of Additional Services which are excluded from this contract, and discussions of Schedule, Fee and Basis of Payment. 1.0 SCOPE OF SERVICES 1.1 Review the plans and calculations for conformance with the requirements of local Planning Board and Zoning regulations as well as standard engineering practice. This review would be specific to drainage design, other factors, e.g. soil testing, which may ultimately affect the drainage design would also be evaluated. 1.2 Visit the property to observe existing conditions on the site, if required. 1.3 Prepare a letter report commenting on the plans and calculations. '101 Accord Park Drive, SUite One 617-.982-5400 Norwell, MA 02061-1685 Fax: 617-982-.5490 2.0 ADDITIONAL SERVICES Coler & Colantonio, Inc. would be pleased to provide the following additional services, if required or desired, for mutually agreed upon additional compensation. Such additional services would involve fees in addition to what is indicated in Section 4.0 of this proposal. Attached is a Fee Schedule which will be used to establish billings for services not specifically covered by this contract. 2.1 Attendance at meetings. 2.2 Additional review or preparation of additional reports. 2.3 Additional field visits. 3.0 SCHEDULE Coler & Colantonio, Inc. will commence work upon receipt of written authorization to proceed. We will perform these services to meet your requirements. Typically two to three weeks are required to perform the tasks listed in the Scope of Services. 4.0 FEE The fee to perform the services listed in the Scope of Services would be $1500 for the information in hand. This is a not to exceed fee for the tasks listed in the Scope. You will be billed based on actual hours worked on the project. Fees for services listed under Additional Services, if required, would be billed on a time and materials basis in accordance with the attached Fee Schedule. The fees described above do not include expenses. Expenses such as mileage, reprographic costs, etc. would be billed at cost plus a fifteen percent (15%) administrative charge. 5.0 BASIS FOR PAYMENT Invoices for services will be submitted monthly. By the signing of this proposal, it is agreed and understood that payment will be made upon receipt of the invoice. The owner/client agrees to limit the liability of Coler & Colantonio Inc. to the owner/client and to all construction contractors and subcontractors on the project arising from Coler & Colantonio, Inc.'s negligent acts, errors or omissions such that the total aggregate liability of Coler& Colantonio, Inc., will not exceed the contract amount. It is further understood that any balances on this account remaining unpaid for a period of 30 days will incur a service charge of 1-1/2% per month (expressed as an annual percentage rate, the charge is 18%). It is further agreed that if said account is turned over for collection, reasonable attorney's fees and costs of collection shall be added to the unpaid balances, whether or not legal action is instituted. Coler & Colantonio, Inc. reserves the right to stop work on the project if invoices are not paid within 30 days of the date of the invoice. Prior to doing any work on the property, we reserve the right to post a notice of contract. The parties to this contract specifically agree that Coler & Colantonio, Inc. has no obligation to release drawings or other documents until the final bill for services has been paid. By signing this letter, you indicate your acceptance of the terms and conditions contained herein and you will give us authorization to proceed with the scope of work indicated. Sincerely, COLER& COLANTONIO, INC. John C. Chessia, P.E. Approved By: Agreed to and Accepted By: James J. Colantonio, Pres. Date: Date: COLER& COLANTONIO,INC. FEESCHEDULE January 5, 1995 POSITION BILLING RATE Principal Engineer and Surveyor $ 120- 135/hr. Division Manager $ 65 - 100/hr. Professional Engineer/ Professional Land Surveyor $ 60 - 80/hr. Project Manager $ 55 - 70/hr. Level 1 Engineer Scientist and Surveyor $ 50 - 65/hr. Level 2 Engineer Scientist and Surveyor $ 40 - 55/hr. Level 3 Engineer Scientist and Surveyor $ 35 -40/hr. Draftsperson $ 35 - 45/hr. Technician $ 25 - 40/hr. Support Staff $ 25 -40/hr. FIELD SURVEY Two -person field crew and equipment $ 75 - 100/hr. Town of orb Andover OFFICE OF �� 5°' 6'^ Z. C M I'TY DEVEL PMENT SERVICES o p 1�000 146 Main Street 3'°aq^rEO Qa°�5 KENNETH R MAHONY North Andover,Massachusetts 01845 �SSACHUS�t Director (508) 688-9533 a FAX TRANSMITTAL COVER SHEET Please deliver the following page ( s ) to : �aro� ��In•�b1-e� C cnAy-c 1 \-nj&c \ Fin C FaI #: sin -I v -ccv A-YcL� ate -C 1-- - CC)l-er c ��c�,1 �c> a� !SUN-- CxzS This transmittal is being sent from. Kathleen Bradley ColwellV-� North Andvoer Town Planner 'PQ�n(s " Fax # ( 508 ) x23 688-9542 Number of pages including cover sheet: ccu-v-_ �\�� 1 � BOARD OF APPEALS 688-9541 BUILDING 688-9545 CONSERVATION 688-9530 HEALTH 688-9540 PLANNING 688-9535 Julie Parrino D.Robert Nicetta Michael Howard Sandra Starr Kathleen Bradley Colwell -LER 17'CILAI 508' t-:z-' 27S97 I'10. SID—D P01 0,8'.'22-'91_1 16:418 Cu -ITOH I COLE C0LAr,QT0r1`v t_ ENGINEERS AND WMENTISTS of Pat,,, post.1V brand fax transmittal i Of I memo 7671 Froffl. AYCOVER SHEET co, Phone Dept. 7 5-4A Fax 0 9.. Fax TO: PAGES COMPANY: FAX NUMBER: Direct Line: FROM: 67- _ tkAt0r4 I&JO76- "5ea7a;k) 4;v PA e46 If you cannot read any portion of this fax, please call our main number 617-962-5400. 101 ACCORD PARK DRIVE, SUITE ONE 611.982-5400 NCRWELL, MA 02061-1685 FAX: 617-982-54'�O 08/2'2i95 1E:43 r OLER COLRHTOhIIO . 50.8' 6182 2397 NO. 892 P02 Ehit_If`JEER9 11&40 ,CIEfid'VIST�_ August 22, 1995 Planning Board c/o Ms. Kathleen Bradley Colwell T own Planner Town of North Andover 120 Main Street North Andover, MA 0184 RE: Engineering Review 80 Flagship Drive Proposal No. 1-487 Dear Ms, Colwell: Coler & Colantonio, Inc, is pleased to provide you with this proposal to pert-brill engineering services associated with the above project. It is our understanding that we are to review the plans and calculations for the above referenced conuxlercial development in the Town of North Andover, Specifically, our review would cover stormwater runoff calculations and design, The plan would be reviewed under the Site Plan Review provisions of the Zoning By-Law. The plans would also he reviewed for conformance to standard engineering design standaitds. Included in this proposal is a Scope of Services which outlines the specific tasks to be performed, a listing of Additional Services which are excluded from this contract, and discussions of Scheduler, Fee and Basis of Payment. 1.o SCOPE OF SERVICES 1.1 Review the plans and calculations for conformance with the requirements of local Planning board and Zoning regulations as well as standard engineering practice. This review would be specific to drainage design, other factors, e.g. soil testing, which may ultimately affect the drainage design would also be evaluated. 1.2 Visit the property to observe existing conditions or,the site, if required. 1.3 Prepare a letter report cominenting on the plans and calculations. 02-,'22/95 16:49 COLER (--.'1DLAt---1T0N I C1 � 508 682 =97 1-,10. 892 IP03 2.0 ADDITIONAL SERVICES Coler & Colintonio, Inc, would be pleased to provide the following additional services, if required or desired, for mutually agreed upon additional compensation. Such additional services would involve fees in addition to what is indicated in Section 4.0 of this proposal. Attached is a Fee Schedule, which will be used to establish billings for services not specifically covered by this contract. 2.1 Attendance at meetings. 2.2 Additional review or preparation of additional reports, 2.3 Additional field visits. 3.0 SCHEDULE Coler & Colantonio, Inc, will comnience work upon receipt of written authorization to proceed. We will perform these services to meet your requirements. Typically two to three weeks are required to perform the tasks listed in the Scope of Services. 4.0 FEE The fee to perform the services listed in the Scope of Services would be $1500 for the information in hand. This is a not to exceed fee for the tasks listed in the Scope. You will be billed based oti actual hours worked on the project. Fees for services listed Linder Additional Services, if required, would be billed on a time and materials basis in accordance with the attached Fee Schedule, The fees described above do not include expenses. Expenses such as mileage, reprographic costs, etc. would be billed at cost plus a,fifteen percent(15%) administrative charge. 5.0 BASIS FOR PAYMENT It is our understanding that our services would be billed to Central Metal Finishing directly. It is our further understanding, Central Metal Finishing is to endorse this proposal although we are directly responsive to the Town of North Andover for the scope of services. 508 2397 G Invoices for services will be submitted monthly, By the signing of this proposal, it is agreed and understood that payment will be made upon receipt of the invoice, T71e Owner/client agrees to limit the liability of Color & Cokultonio Inc, to the oi".ier/client and to all construction contractors and subcOntraCtors on the project arising from C'alcr Colantonio, Inc.'s negligent acts, errors or omissions such that the total aggregate liability Of Color& Colantortio, Inc., will not exceed the contract amount. It is further understood that any balances on this account remaining unpaid for a period of 30 days will incur a service charge of 1.1/2% per month (expressed as an annual percentage rate, the charge is 1.814), It is further agreed that if said account is turned over for collection, reasonable attorney's fees and costs of collection shall be added to the unpaid balances, whether or not legal action is instituted. Color& Colantonio, Inc, reserves the right to stop work oil the project if invoices are not paid within 30 days of the date of the invoice. Prior to doing any work on the property, we reserve the right to post a notice of 4ontract, The parties to this contract specifically agree that Color & Colantonio, Inc, has no obligation to release drawings or other documents until the final bill for services has been paid, By signing this letter, yoti indicate your acceptance of the terms and conditions contained herein and you will give us Authorization to proceed with the scope of work indicated. Sincerely, COLER& COLANTONIO, INC. / ohn C. Chassis, P.E. Approved Ley: A- reed to and Aocepted for B ' of Payment By James J. Colantonio, Pres. f, -' Date; g 2 0°,!'`'2/951 16:50 i_:I ILEF' [:IJLHf`aT[It'a1J 303 IJ2-2 23,97 110. 392 IP05 CGLER& COLANTONIO, INC, FEE SCHE.OULE January 5, 1995 THT Principal Engineer and Surveyor $ 120- 135/hr, Division Manager $ 65 - 100/lrr. Professional Engineer/ Professional Land Surveyor $ 60 - 80/lir, Project Manager $ 55 e 70/br. Level 1 Engineer Scientist and Surveyor $ 50 - 65r`hr. Level 2 Engineer Scientist and Surveyor $ 40 - 55/hr. Level 3 Engineer Scientist and Surveyor $ 35 - 40/hr, Draftsperson $ a 5 - 45/hr, Technician $ 25 - 4011.r. Support Staff $ 25 - 40/hr. YIELD SURVEY Two -person field crew and equipmertt $ 75 - 100ft. 09. -1151 'D5 1G.:217 t-:1-JLER COLR-IT01--.110 � 508 b82 2397 1,10. 953 P02 COLER & COLA11*'N'TON1O \r,.jo 2c:F-f September 5, 1995 Ms. Kathleen Colwell Mr. Michael D. Howard Plaiining and Conservation 120 Main Street North Andover, MA ()I 84-S RE: Engineering Review 80 11agship Drive Building Addition and Parking Lot Expansion Dear Ms. Colwell: In accordance with our proposal ol'August. '22., 1995 Coler& Colantonio, Inc, has reviewed the plans and calculations for the above referenced project. Our review - -teally addressed drainage and stori-nwater runoff aspects of the design, it is our specif understanding that other aspects of the design would be reviewed by in house staff. We also compared the design assuniPtioll's and calculations with.standard practices outfii-ied in Soil Conservation Service (SCSI) runoff calculation documents and other standard engineering references. This correspondence is a result of the above revieNv and includes our comments on the submittal pack-age. The following documents were reviewed: • A plan entitled"Pre-Development Hydrology" prepared for Central Metal Finishing, prepared by Thoma,,,E.Neve Associates, Inc, dated August 9, 1995. • A plan entitled`Post-Development Hydrology" prepared for Central Metal Finishing, prepared by Thom-as E. Neve Associates, Inc. dated August 9, 1995, • A plan set iiieluding plans entitled "As-Built/Permitted Plan,North Andover Business Park"; and "Existing Conditions", "Site Development Plan", "Engineering Details" and a floor plan of the proposed addition for Central Metal Finishing. Analysis of• A report entitled "Flydro logic An Central Metal Finishing"prepared by Thomas E. Neve Associates, Inc. dated August 1995. The parcel is located on Flagship Drive, an existing industrial subdivision. The lot is currently developed with a building and parking/loading area. Drainage from the site is tributary to wetlands located at the southwest corner qf`the lot and the subsurface storm proposed to construct a 9,500 sf building drainage system located in Flagship Drive. It is proposed addition and expand the parking area. '09/05/95 ib:2718 COLER COLANTUh1I0 508 682 2397 HO. 953 UO3 We offer the following conurients: Existing Conditions: 1/ Subcatclunent 1: The woods and grass area included in the CN calculations is not cleanly defined froze the woods area on the Pre Development Hydrology Plan, 2. Subcat6nient 1: The time of concentration(T,) calculation for math 2 indicates 30' of sheet flow through a wooded area. The treeline on the Pre-Development Hydrology Plan scales 17 feet. The remainder is identified as grass. /Subcatchnient 3: A soil pile/gravel area is indicated on the Pre-Development Conditions Plan but is not included as a cover area in the CN calculations. This should not impact the model. /4. Sulbeatchniont 3: No information is provided on the slope of the soil pile Lased in the ulation of T�., A spot grade indicating the height of the pile�voulcl be sufficient to evaluate this. Proposed Conditions: 5 Drainage divide between Subcatchments 2 and 3 should be further south. to account or the proposed grading. Subcatchment 5: Treeline indicated at the easterly portion of the subarea does not snatch that of the Pre-Development Hydrology Plan. The treeline indicated on the Post-Development Hydrology Plan is wider. from treeline to property line than on the Pre-Development Hydrology Plan. Additionally, trees indicated in the northeast corner of ,Suhcatclunent 1 on the Pre-Development Hydrology Plan are no( indicated in the northeast corner of Subcatchment 5 on the Post-Development Hydrology flan. It appears that no work will be performed in this area, 7. o information has been provided on the capacity of the existing downstream storm drainage system in Flagship Drive to control proposed runoff from the site. A previous drainage analysis for the abutting lot (94 Flagship Drive) indicated the storm drainage system would be surcharged under some storm events, This may result in a surcharged condition for on-site drains. If on-site drains are surcharged an outlet control condition may occur at the detention basin. The model considers open channel flow with no downstream control. This should be investigated. S. In our opinion the two foot width at the top of the detention basin berm and 1:1 side slopes are inadequate from a safety, stability, and maintenance standpoint. We recommend detention and retention ponds be designed in accordance with ASCE Manual and Reports of Engineering Practice No. 77. Plans indicate rip-rap will be used to line the bottom and sides of the basin however no dimensions were provided on stone size and lining thickness. A detailed cross-section of the basin and beini should be provided, 09/05 `95 16:29 i=OLER COLRHT01,110 y 508 632 27-97 1.10, 953 PO4 9. No derail information was provided on the outlet structures (i,e., orifice and ernergency overflow catch basin). The proposed 5.5" orifice is likely to be a maintenance problem. Details of how this Structure will be kept. clear of debris should be provided, 10. An emergency overflow spillway for the detention basin should be designed for larger storm events in the event that the outlet orifice and catch basin are plugged with debris. This spillway should be sized to pass a 100-year storm with the outlet plugged. The detention. basin could be modeled as dry at the start of the storm. We suggest the spillway be located at the southern side of the detention basin to ow for emergency discharge to the wetlands, 1 test pit. data has been provided with the "I�ydrologic Analysis'" (Report). This ormation is useful to compare field information with Soil Conservation Service (SCS) mapping of they area. The area classified as hydrologic soil group "M may have been a wet area that has been filled. The soil used as fill may be of another hydrologic soil group. In addition, test pits should be excavated in the proposed detention basin, Without test pit data it is not known if the proposed detention basin will he in groundwater, Test bits in the proposed detention basin should be performed by a certified soil evaluator and include information on. estimated maximum groundwater elevations in the area, L. Little information was provided on the proposed roof drainage system, It is unclear how it services the proposed building, at what elevation it discharges to the detention basin}., and for what storm event the drain capacity is designed, No indication of overflow scuppers is included, 13). The discharge capacity of the 6.2' x 2.2' horizontal orifice/grate in the detention basin appears high. No data was provided on the type of grate proposed for use. Information on the grate design and how its capacity was calculated should be provided. Ge711 ,6/h 1'ortions of the site appear to be possibly located m the F ~MA flood zone. >,he sitee when scaled from the "As-Built/Permitted Flan,North Andover Business Park" and scaled onto the Flood Insurance Rate Map Panel Number 0006, appears to be in Zone, ' A, Zone A. is contained in the 100-year flood zone,however, no flood elevation has been determined in the area by FEMA. We reconinlend the Applicant investigate this /5Prec,'ist yWe suspect that.flood elevations have been altered in this area.concrete Oiemical storage units are proposed to be relocated to within the ctl�rild buffer Zone and located on a concrete pad with associated retaining wall. We suggest.additional data on the contents, capacity, and construction of the chemical storage tanks be provided to the Conservation Commission for their evaluation of the � G_9 CIS '95 1 G,:7CJ COLER :--:1--1LAHTOH10 -* 50'Ei GER2 2397 1,10. 953 P05 proposed location. Detail infort-riation should also be provided for the associated -ticrete pad and retaining walls, I It "appears that the proposed parking area at the site's south side slopes at a 0.3% slope, Typically a slope of t% (min,*) is desirable for proper drainage o[parking areas and roads. The proposed grades are likely to result in ponding on the pavement, In addition., spot elevations at the south side of the proposed building addition indicate the ground sloping in the opposite direction of the parking area (i.e., easterly away /" -)'n the detention basin), I ' Spot elevations should be indicated at both the south and east side of the existing �3uilding and the proposed addition in sufficient density to assure proper drainage, 18. Proposed grading at the southwest comer of the site suggests that elevation 248 be cut back approximately 15 feet at its greatest point indicating grading within the wetland limits. We suggest "tying"the proposed grading into the existing grading without altering the grades within the wetlands. 19 is unclear liow the loading clock at the nw.ihive.st side of the proposed addition will Vbe operated. it appears on the Site Development Plan that a driver would have to maneuver around parking spaces and railroad ties. The Site Development Plan does not clearly specify whether or not the edge of pavement is to be revised and the existing railroad ties and parking spaces to be removed. The Proposed parking area revisions should be highlighted, We appreciate the opportunity to assist the Planning Board on this project and hope that this information is sufficient for your needs. If you have any questions please do not hesitate to contact us. Very truly yours, COLER & COLANTONIO, INC, Jolm C Cliessia, RE, l__t'=+ ; 2.51 C.i=ILER (=CILF I11TC111 I Ci 50: E -5' r 110, 146 P01 L LAI + 1 FACSIMILE COVER SHEET To: Kathleen Colwell & Michael Howard Company: 4-own of Noilh A.n.dover Phone: (508) 688-9535 Fax: (508) 688-9542 From: Jolla Chess'14 Company: Coler dT Colantonio, Inc. Phone: (617) 982-5443 Fax: (617) 982-5490 Date: September 27, 1995 Pages iijeluding this cover page: 4 Comments: Supplemental review of 80 Flagship Drive - Central Metal Finishing copy to f homas E. Neve.Associates DID,,27!CD5 12:52 COLER COLAHT101,110 5108 6E-12 27-97 HO. 14G, P02 COLER COLANTOINIO ,= Septernber'27, 1995 Ms, Kathleen Colwell Mr. Michael D. Howard Planning and Conservation 120 Main Street North Andover, MA 0)845 P,E: Supplemental Engineering Revie\y 80 .Flagship Drive Building Addition and Parking Lot Expansion Dear Ms, Colwell & Mr. Howard. Ceder & Colantonio, Inc. has reviewed revised plans, calculations, and the response letter dated September 12, 1995 all prepared by Thomas E, Neve Associates (TENA) for the above referenced project. Our review focused oil.TENA's response to comments in 0-11' letter dated September 5, 1995, Commients in this letter are numbered to correspond with our September 5 letter. Where a comment was satisfactorily addressed we have so Stated, If the response to our comment was not adequate we have described our concerns. Existing Conditions: 1. Satisfactory, Satisfactory. 3, Satisfactory, 4. Satisfactory, Proposed Conditions'. 5, Satisfactory, 6. Satisfactory. 11 7 We recommend that the hydraulic grade line of the existing and proposed storm drains be calculated to determine if an outlet control condition would exist at the proposed detention basin. While it is tnie that under a surcharged condition flow would discharge through the catch basin grate downwearn, the level the water would reach at a given point varies as one moves upstream and could impact the outlet from the detention pond. 09/27/95 12:52 C-. LEP COLR]TON 10 � 506 C-82 2397 1'10. 146 PCIO 8, The pond has been modified to have an acceptable width and side slope. The proposed six inch rit) raI2 surface should have suitable filter fabric under it to prevent t ie growth of nuisance ve etation and stabilize the soil/stone interface 9 Additional details regarding the orifice and catch basin overflow structures have been provided. The model number and total PZ igg uizg proUided on the beehive grate is not specified. it is possible that the 2.ate could be more of a restriction thaxr the This information should be provided. We recommend a maintenance program to keep the structure clear of debris be made a part of the Order of Conditions. 10. As stated in TENA's response, if the detention basin is overtopped, flow would discharge to the south and west sides of the pond. An emergency overflow spillway should be provided at this location to prevent the dike from being er-. in the event that the outlet orifice and catch basin are plugged with debris. This spillway should be sized to pass a 100-year storm with the- outlet plugged, The detention basin could be modeled as dry at the start of the storm. We suggest the spillway be located at the southern side of the detention basin to allow for emergency discharge to the wetlands. This spillway would be for emergency conditions only and would hopefully never see any flow. If the dike is overtopped and erodes, which is more likely if stone is not provided on the downstream slope, considerably more water would discharge from the pond and potentially greater damage would result to abutting properties than if the excess runoff is directed to flow over a stable emergency spillway. 11. No test pit data has been provided with the "Hydrologic Analysis" Report). This information is useful to compare field information with Soil Conservation Service (SCS) mapping of the area. The area classified as hydrologic soil group "D" may have been a wet area that has been filled. The soil used as fill may be of another the model somewhat, Test pits are also hydrologic soil group, which would after useful to determine if the presence of groundwater will be a concern in the proposed detention basin. TENA has agreed to perform test pits in the detention basin and on-site. These test pits should be performed by a certified soil evaluator stimated maximum groundwater elevations in the area. and include information on e C� If test pi ts indicate, different conditions than assumed the plans may have to be modified. r�ee.c\ \-b co4Ar,-,-N A-na+ 12. Satisfactory, pyj\NdCC\ 5,2-e 3 - R� OJS 13, The calculations of the capacity of the catch basin grate appear to be greater than Neenah Foundry flow estimates for ponded flow, however, this is structure is not designed to receive flow except under extraordinary conditions and we do not anticipate a problem with this aspect of the calculation. 09/27 -35 12.55 COLER COLAHT01,110 -. 508 6822 '2397 110, 146 IP04 General: 14, Satisfactory, 15, satisfactory. 16, Satisfactory. actory. 17, Satisfactory, 18, Proposed grading around the detention basin is within 25 feet of the wetland. This will require approval of the Conservation Commission. N. Satisfactory, We appreciate the opportunity to assist the Planning Board on this project and hope that this information is sufficient for your needs, if you have my questions please do not hesitate to contact us. Veiy truly yours, COLER & COLANTONIO, INC. "/John C, Chessia, P.E. xe Thomas E. Neve Associates 12101:"95 12:0G, DDLER COLAHTi-4,110 50 6 '9542 rl1 r POI COLER & e t0 W IJ PLANNING BOARD FACSIMtLE COVER SHEET To: Kathleen Colwell & Michael :Howar'd Company.- Towel of Noilh Andover Phone: (5018) 688-9535 Fax: (508) 688-9542 From: John Chessia Company: coler & C'ol"111rollio, 1110. Phone: (617) 982-5443 F'ax: (617) 982-5490 Dates DecembeI' 1, 1995 Pages including this cover lan e: 4 Comments: Supplemental review of 80 Flagship Drive - Cemral Metal ftnislxin copy to Thomas E, .Neve Associates 12 "01/95 12:C16 COLER COLA[1TO1-,J 11--1 -4 508 688 9542 NO, G-17 P02 COLANTUIN102 AND SUENTIST-5 December 1, 1995 Ms, Kathleen Colwell Mr. Michael D. Howard Planning and Conservation 120 Main Street North Andover, MA 0 18,15 RE Additional Supplemental Engineering Review 80 Flagship Drive Buildhig Addition and Parking Lot Expansion Dear Ms. Colwell &Mr, Howard: Coler & Colantonio, Inc. has reviewed revised plans, calculations, and the response letter dated November 17, 1995 all prepared by Thomas E. Neve Associates (TENA) for the above referenced project, Our review focused on 'FENA's response to comments in our letters dated September 5, 1995 and September 27, 1995. Comments in this letter are numbered to correspond with our Septernber 5 letter. Where a comment was ,satisfactorily addressed we have so stated, if the response to our comment was not adequate we have described our concerns, Existing Conditions: 1. Satisfactory. satisfactoty, 3. Satisl'actory. 4 Satisfactory, Proposed Conditions: 5 Satisfactory 6. Satisfactory 7, ' 'rENA have computed a hydraulic grade line for the existing storm sewer system as requested, existgrlanld inud es inflow to the ng systeni,bo,th L)re (t�2�1�t con StTUCUOn to pr Sr dijt4� he, -p _jy_qj!�_ i ni-I p 4, of orn the detention basin will Jjkeiv g��_pEqj In any event the C)Utlji i�' operate under outlet control (i,e. the outlet (irifice would be submerged on the downstream side of the outlet) during larger storni events. This would change some 12 '01/95 12-07 COLER COLAHT01.1 10 - 508 630 9542 [.110. ell 7 of the assumptions used to calculate outflow form the proposed detention basin, Ali Outlet control condition would reduce the outflow from the detention basin and raise the flood elevation in the basin, Based on preliminary performed by Coley., & Colantonio, Inc, utilizing data presented with ,the applications for 80 'and 94 Flagship Drive, the e%11stin8 street drainage system would uiredan 0 year storm event, To properly model this condition would req ""—" extreme v colliple'-x-in" _d'e"T We recommend that TENA compute the total runoff volume in acre, > feet both pre and post construction and assess the impact to receiving areas if the detention basin does overtop. It may be necessary to enlarge the basin to account for reduced discharge due to outlet control. conditions during larger storm events, 8, Satisfactory, 9, The beehive grate is acceptable. We recommend a maintenance program to keep the ,structure clear of debris be made a part of the Order of Conditions, 10. Ail emergency spillway has been provided, We recommend that this spillway invert be raised to EL 251,5 or higher as an added margin of safety to overtopping over this structure. 11. No test pit data has been provided with the "Hydrologic Analysis" (Report), This information is useftil to compare field information with Soil Conservation Selltice (SCS) mapping of the area, I'lie area classified as hydrologic soil group "M may have been a wet area that has been filled. The soil used as fill may be of another hydrologic soil 'group, which would alter the model sornewhat. Test pits are also useful to determilie if the presence of groundwater will be a concern in the proposed detention basi'n' 'IENA has agreed to perform test pits in the detention basin and on-site. These test pits should be performed by a certified soil evaluator and include information on estimated maximum groundwater elevations in the area. If test pits indicate different conditions than assumed the plans may have to be modified, 1`2. Satisfactory. 13. The calculations of the capacity of the catch basin grate appeal, to be greater than Neenah FOUndry flow estimates for ponded flow, however, this is struCtUFe is not designed to receive flow except under extraordinary conditions and we do not anticipate a problem with this aspect of the calculation General: 14. Satisfactory, 1.5. Satisfactory, 16. Satisfactory 1 7. Satisfactory 12/01/95 12,:C1 S COLER COLAHTONICI - 508 6,8-81 9542 NO. 617 EP04 18. Proposed grading around the detention basin is within 25 feet Of the wetland. This will require approval of the, Conservation COMMiSSiOn. 19 Satisfactory. We appreciate the opportunity to assist the Planning Board on this project and hope that this inforni,,itlon is sufficient ffir your needs. If you have any questions please do not hesitate to contact us. Very truly yours, CQLER& COLANTON10, TING /X1o0J . C 1hn 111 C C C hessia, P.E. xc Thomas E. Neve Associates / '95 15:5 7 TI_ 5CIi_i f_i82 ._39 P01 CENTPLAL 1 niftwiRY mn l METAL FINISHING FOR THE AEROSPACE AND RELATED INDUSTRIES 1 TO: DATE GGMP'AM FROM: ��rlwll j NO. O PAGES TO FOLT SHEET MESSAGE,* Z4 r i 80 R09ship (rive, No Anc over, MA 01845 • (508) 685-4811 Fax (508) 975-1123