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Home My WebLink About1991-02-25 91-99 ORDERCouncil Action Date February 19, 1991 Item No. 91-99 Item/Subject: Order authorizing Engineering Contract Amendment Reapomible Oepar(mem: Conammity S Economic Development /Airport Commentary. This item is to ratify the decision o£ the Community b Economic Development Committee t0 amend the current contract with OEST Associates for the completion of a drainage plan for Bangor International Airport. The project will delineate a physical development plan for accommodating storm water runoff and fuel spillage containment for the majority of the airport land (watersheds 1 and 2which drain towards Union Street) and will be designed for a 20 year build-out of aeronautical autical and n aeronautical development. The project cost i up to $48,640 and includes ae�r}}'1��t,.qq ographic mapping for the entire airport. The Airport heaEdsp'd351t will be the source f funds for the project. It i anticipated that the project cost will be reduced due to prior topographic mapping being available for a small portion of the study area. pvpanm.mxw Managers Commenn: C,tyMa�mger 4knpmile4 In(oellm(1011. Eudod Approval. W4(-03 pmeaaen,..weo. LeelApproval. ForySMienar - Introduced For C Ota/ Ea(1 Wastage 0 Fint Reading - - page_ot_ Q Referral 91-99 Aoip ed b f ci or Bragg, February 25, 1991 CITY OF BANGOR (Imf.) (Drbtr,--...._BrthortEittl the city 11ana9ar' to Sign an EngL ing Cmtrnec AmaWmR By me aro couneH Of Ad OHv olBn*Eor: ORDERED, . THAT �, paq r of 8rnlxcmrental Ptotation applications am being developed for erpv = of the ALXPn 19mdnal Briltliig, parking lot and Hilton Rotel: and vat88et5, a s1.ve plan is needzd to aditess stoon cater drainage a fuel crn� issues for these atl £uGae aeronautical and m- n� devslcgmaR at BiA, and HHKREA9, O Asasiatea is cur ly uM¢ wntrec[ to crap e tle posF1971 u applicaUan for BM and historical storm water. analysis is Part of that project; 1i�Igia.'r BE rr O BBgB that iln City mna9 is auClwrittd w sign a contract for an additiaal anwnrc up to $48,640 for tte pur{ of aerial topographic napping a a drainage plan at BA, M, BE M MIR6161i OBOEBEO MB $48,640 ba traaferrad frta Pemwt W. 8501-M051 T fens to Otter Bun& i Pttwnt Ho. 85-01-03.01, Special �, for this prx . IN CITY COUNCIL February 35, 1991 Passed CITY 'pg 91-99 6TZi�i9 Title, .. iVS49xiei4g, the,C(SY. �P44g4S.44.51gv an Engineering Contract Amendment .....'.((y../yy........�./.................... (�^ zz OMCdIaNn BANGOR INTERNATIONAL AIRPORT GTOANNATBR ➢MTNAOE STUDY <Dbl'I;S,I�iF:P3 91-99 a. From our work in developing the Post 1970 conditions for the DEP application, we have an excellent understanding of the information available about the airport. Military plana and more recent aerial photos provided a substantial amount of information. Yat, there are some areas lacking sufficient information to be completely accurate. The most recent topographic mapping was last revised in January, 1965 and we expect that some of the topography has changed due to continuing construction. It would be beat if a new topographic plan could be obtained with 2' Contour intervals provided. This would provide positive vertical control and precise delineation of drainage boundaries. The cost and time to obtain this data is substantial however. While we would prefer to work with the most accurate base information available, we feel an adequate study can be conducted using existing data, recognizing that some inaccuracies may occur, particularly when establishing the drain basin sizes and flow paths. As an alternative to obtaining new topographic data, we can proceed with existing data. Tho City can select either option. - b. In either case, some field verification of data will need to be provided. This will require a survey crew to spend time at the airport along with an engineer. The was of existing topographic data will require mora field verification than if new topographic data is available. c. Based on the updated field data and the information in the Post 1970 application, a plan of the existing etormwater System will be developed. Thin will show existing flow patterns, System capacities, and peak runoff rates for each watershed utilizing SCS TR -55 methodology. a. tad use changes, as proposed in the Airport Master Plan and the Strategic Sand Use Pian for non-aaronautical land, will be seeped. Included in this will be proposed changes to the ANG property and land west of the runway which naturally drains into the existing stormwater System of the airport. Road realignments, increases in natural Cover and permanent water bodies x111 be Included. Areas designated for future development, which 91-99 are non-specific, will be factored with a reasonable amount of impervious surface area. b. Runoff data for projects currently in the planing process, (specifically the expansion of the terminals and the expansion at the Hilton and associated parking for both) will be Incorporated assuppliedby the project consultants. c. As for the existing conditions plan, the peak runoff rates for each watershed will be calculated utilizing the SCS methodology TR -55. d. The flow patterns of water from the various watersheda to the outlet point(s) will be evaluated. New drainage systems will be located and sized as necessary to effectively handle deficiencies in the existing system. These systems may include pipes, culverts, ditches, and detention/retention. e. Special features will be designed to Handle the separation of oil and petroleum products, glycol, and fire fighting foam or similar agents. Also included will be detention ponds to provide for the controlled role&$* of storm flows into the Nenduskeg River. Preliminary design of the size, location, and operation of these ponds will reflect the aesthetic objectives of the various airport long term plana. a. AaoorE The results of the above work will be summarized in a report including all of the assumptions, calculations and data upon which the design is based. Plans and figures will be part of the report. Five (5) copies of the report will be provided. An opinion of probable construction coat for the recommended facilities will be provided in an itemized format. These coats will be separate from the report since coats change with ties and will become inaccurate eventually, while the design recommendations should remain valid for the period specified (30 yearn). -MTT IWI LTi Throughout the term of this project we will coordinate with the City staffs .airport staff, military personnel, and others designated by the City as having input in the process. Regular updates and meetings will be held to keep all members informed.