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HomeMy WebLinkAboutConsultant Review - 94 FLAGSHIP DRIVE 7/6/1995 eT----), f�-' - , �Z" 3 W -- — U L—L--- "01 ANTONIO 11 a6 i Q 45 Planning Board NIS. 1"ahlet:11 Bmdl'r v i' lo"n of Norl Andover lip 10 Mahl SIM Aiidovt:i% NJA 01845 N-k 94 it!Sop QN, prnposal IN(), i-4-4" 1 war his, (f A"'ell: ("oler & Cotantonio. Inc, is pleased to provide with this proposal to perfoml migineering services associated Wh the above proicet it is our understanding that we arc d calculations for the above referenced comn-,ierciat to reviow the plan anti calculatit development in dhe Town ()f North Andover. Spec i tically, our review would cover stc The plan would lie reviewed under the wile -im-mater runoff calculations and desig n, w b Plan ReWew provisions of the Zoni'V By-Uw, The plans would also be reviewcd W, conlonn• nce w 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. Fcc and Basis ot'Payment. I m SCOPE Or, SFIRVIC VS t.1 JZ,e�,jew the plans and calculations fir conformance with the requirements of local Phnning Bond and Zoning regiflations as well as standard engineering practiG-,, This review would be specific, to drainage design, {}Biel' a -, ii-11 testing, -which may ultimately affect the drainage desii,m would also 'he eve fluated, vi- ,it tj)e property tee obi nerve existing. conditions on the site. 1 .3 Prepare a lotler report connmntin�, on the plans and calculations. Coler& Colantonio, Inc. would be. pleased to provide the following additional services, iF required or desired, fOr mutually aureed union additional compensatiozi, Such additional services would involve fees in addition to \what is indicated in Seelluit 4 0 of this pro �1tt��ctied is a Fee Schedule which w 11 be used to establish billings for �ervices not specilically covered bv tliis C'd?ntract. �., f �tt{�nl�in�:v it lliE'f!t'1Lw. 2 Additional review or preparaiion of additional reports. \L�(ilti4lii ( i-iold v"i?it s. 'A 113AA)LE toter tY t_olamonlo, Inc, wilt commence ,vork upon receipt of written authorization to rn-oceed. �k e will perfc]t�t�t these selviccs to n�e,et your requirenieiits. Typically two to three \-veeks are required to pet'limin the tasks listen in the Scope of Services, i he lee to perf-rin the services listed in the, Scope of `services would by $1500 fi)r the in])rmation in kan-L Ihis i:; a not to exceed fee for the tasks listed in the Scope, You \viii be billed 'based on actual hour; worked on the project. fees for services listed under Additional Services, il' required, v,-ould be billed on a time and materials basis in accoruan(ce with tlic attached 1i e chedute. I he Zees described above do not include expenses. E,,gm]ses such as mileage, rcprogrttphic costs, etc., would be bliled at cost plus a fit-wen percent (15%) aditiinistrative A—,x -m Invoices for scrvic,O \vill be submitted monthiv. By the sicming of this proposal, it is agreed aim understood ttiw, pav nent wth tie made upon receipt of the invoice, The o vner client agrecs to limit the liability of Soler (V. t'oiantonio Inc. to the ctti\ner/clieiat and to all constructir_�i] c,outractors and sut?cont.ractorw on the project arising from Coler & c_.olantonio, lric.'s negligent elxors or omissions such that the total aggregate liability ur'Culcr & ColantciniO. lr]c., will. '-lot exceed the contract :miount. It iF fi flier understood thm ariv ori this accOunt remainiri« unpaid 161 a pericid of )i will incur a service charge of I-I_M'-o per i1 .7rlt.li (expressed as an animal Vcreentage rate., the c.lial''Te is 0 lu0 w). It is further arced that if Faid a;:cotiltt i4 turtied over for collcctiori, reasc7nahle- auornal' ices and costs of collection shall be added to tfte unpaid balances,. whether or not legal action is instituted. Corer & Ci�l;-ititonio, hic. reserves the right to stop work on the project. it invoices are not paid within 30 dad's ofthe date of the invoice. Prior to dolllg any worst on the properM we reser e the rinlit to post a notice of contract, i-he paities to this contract specifically aoree that Ceder & r'oiantonio, Inc. has no obiigation. to release drawings or other documents until the I`mal bill too services has been B,, si t7ia? this letter, }'all indicate Four acceptance ofd- terms and conditions; contained herLiti and vOU Will rive us tic1tI1OM/-U6O.D.to proceed with the scope of work indicated. r A creed to in(! ,-1cC;tp(O-C_i BV: nw, W. & COLANTON10 0z ENGINEERS AND SCIENTISTS July 18, 1995 LANNING Ms. Kathleen Colwell Town Planner 120 Main Street North Andover, MA 01845 RE: Engineering Review 94 Flagship Drive Parking Lot Expansion Dear Ms. Colwell: In accordance with our proposal of Coler& Colantonio, Inc. has reviewed the plans and calculations for the above referenced project. Our review specifically addressed drainage and stormwater runoff aspects of the design. It is our understanding that other aspects of the design would be reviewed by in house staff. We also compared the design assumptions and calculations with standard practices outlined in Soil Conservation Service (SCS) runoff calculation documents and other standard engineering references. This correspondence is a result of the above review and includes our comments on the submittal package. The following documents were reviewed: • A plan entitled"Site Plan of Land in No. Andover, Mass.,"prepared for Development Assoc., prepared by David E. Ross Associates, Inc. dated June 1995. • A report entitled"Drainage Calculations Development Associates Flagship Drive North Andover, Massachusetts,"prepared by David E. Ross Associates, Inc. stamped on June 23, 1995. We offer the following comments: 1. The parcel is located on Flagship Drive, an industrial subdivision. The lot is currently developed with a building and parking/loading area. Drainage from the site is connected to the storm sewer system in Flagship Drive. Wetlands are located at the southeast corner of the lot. It is proposed to expand the parking area, no expansion of the building is proposed with this submittal. 2. Contours on the plan are inconsistent at the area identified as Pond 1, and near the wetland limits north of the replication area adjacent to the fill pile. Adjustments to the contours in these areas may impact the amount of wetland filling required. 101 Accord Park Drive, Suite One 617-982-5400 Norwell, MA 02061-1685 Fax: 6'17-982-5490 3. Our measurement of wetland fill and replication areas indicates approximately 870 sf of fill and 730 sf of replication. 4. No inverts are indicated for the interceptor drain. The detail references the plan for elevations of the interceptor drain, however, this information is not provided. 5. Flow paths used to determine the Time of Concentration (Tc) should be indicated on the subarea plans. 6. The Tc calculations for subarea 1, under both existing and proposed conditions, appear to be too long. Our experience has been that woods with dense undergrowth is uncommon in the northeast. In addition, the calculation of flow time for the shallow concentrated flow segment is longer than estimated using the SCS TR-55 program. Using a longer Tc results in a lower peak rate of flow. In this case since the values are the same under pre and post construction conditions the impact to the design is anticipated to be minimal. 7. Subcatchment 5 does not reflect additional paving which is proposed to be added to the subarea. Adding pavement will increase the peak runoff rate. 8. The model does not accurately reflect the grading with respect to subcatchment 6. The plans indicate a detail of a proposed cape cod berm which appears to be installed around the perimeter of the proposed parking area. In addition,the grading directs flow from subcatchment 6 to existing catch basin 4. This subcatchment should be combined with subcatchment 2 since both areas discharge to the same location. This will likely result in a higher peak discharge from catch basin 4, since flow would not be routed through the swale and would concentrate more rapidly at the catch basin. It is anticipated that adjustments to the model to reflect the above comments would result in a larger difference between pre and post construction peak runoff rates. The submittal package did not address the capacity of the downstream system. If the overall subdivision was designed to handle the flow from the site as currently before the Planning Board and Conservation Commission, an increase in runoff rate may be acceptable. 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. t /r /` John C. Chessia, P.E. 08/01/95 14:55 COLER COLRNTOH 10 -* 503 632 23997 HO. 796 P01 COLER & COLANTONIC-J � AN 8%^'!F-NTIST5 FAX CovER SHEET DATE: F PAGES 12 _ r�� . FAX NUMBER: Direct Line: FROM:. 6'97.982®54+3 0- 'Al o if you cannot read any portion of this fax, please call our main number 617-982-5400. 617-982-5400 101 ACCORD PARK DRIVE, SUITE ONE FAX'. 617-982-5490 1/05 14:55 COLER COLRATOH10 y 508 582 =97 No.705 P02 COLANTONIOZ FNGINAR=RS AND SCI�:N rib 13 August 1, 1995 Ms. Kathleen Colwell Town Planner 120 Main Street North Andover, MA 01845 RE: Additional Engineering Review 94 Flagship Drive Parking Lot Expansion Dear Ms, Colwell: Cofer& Colantonio, Inc, has reviewed the revised plans and calculations for the above referenced project. Our review specifically addressed drainage and stormwater runoff aspects of the design. This correspondence follows the numbering system of our letter of July 18, 1995, where a comment has been satisfactorily addressed we have so stated, We offer the following comments: 1. No response required, 7, Satisfactory. 3. No wetland alteration is proposed with the revised submittal. 4. Satisfactory. 5. Satisfactory, G. Satisfactory. 7. Satisfactory. 8, The location of the "cape cod berm"has been clarified. It appears to be placed directly on the pavement to act as a gutter for runoff. This will direct runoff to the swale; as calculated in the report. 9. The calculations indicate a larger increase in post development runoff than the original submittal. The regulations require that there be no increwse in runoff rate post development. As stated in our first review, if the original subdivision plans included provisions designed to mitigate the anticipated runoff from this site post 1/95 14:56 COLER COLAHTOhd I O 3 508 682 2397 NO.795 P03 development, an increase may be acceptable. The calculations provided, which Address the capacity of the existing storm sewer system, consider pressure flow(i.e. the level of water in manholes and catch basins would be well above the top of the pipes). Typically, storm sewers are designed to function as open channels, It is not known what the criteria was at the time of the original subdivision. The existing system would be undersized based on open channel flow design criteria, We agree that the increases in runoff from the site is small, however, the Planning Board should also consider the implicatimis of incremental increases from other development in the area, 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. Xohn C. Chessia, F.E. xc David E, Ross Associates