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HomeMy Public PortalAboutAdd#7 - Bright St Drainage.pdfADDENDUM #07 ADDENDUM # #07 DATE April 30, 2018 ADDENDUM TO CONTRACT City of Tybee Island - City Engineer DATE OF CONTRACT February 28, 2018. PROJECT: CITY OF TYBEE ISLAND BRIGHT ST. DRAINAGE IMPROVEMENTS THE CITY OF TYBEE ISLAND (Owner) and THOMAS & HUTTON ENGINEERING CO. (Consultant/Engineer) this 30TH day of April 2018, amend their contract dated February 28th, 2018 for work, materials, or services described below. I. SCOPE OF WORK: A. Survey Phase 1. Topographic Survey Phase Thomas & Hutton Engineering Co. will perform a topographic survey along Logan Street, Bryan Avenue, Bright Street, Campbell Avenue, Solomon Avenue and Van Horne Avenue to assist in the design of drainage improvements. The approximate length of the survey corridor is 3,500 linear feet. Survey corridor width will be the road right of way width plus ten feet on either side of right of way. The survey will include the location of ditches, drainage structures, pipes and drainage outfalls. Road cross-sections will be taken at 100' intervals and at high and low points. Cross-sections will also be taken through the median between Solomon Avenue and Van Horne Avenue. Along the south side of Logan Street, building faces will be located and finished floor elevation and existing ground elevation at the structures will be obtained. Right of way lines will be re-established for the existing roads in the survey project area. Property line data for adjoining and adjacent parcels will be shown based upon Chatham County Tax Assessor information. Underground utilities will be shown based upon the location of surface appurtenances. Subsurface utility designation is not included in this scope of work. Horizontal datum and vertical datum for the survey will Georgia State Plane Grid, East Zone NAD83 and NAVD88, respectively. Deliverable will consist of an AutoCAD CiviI3D file. Survey Phase Lump Sum $15,300.00 B. General Study/Report Phases The Consultant shall create an ICPR 4, 1 -Dimensional model to simulate stormwater flow through the existing stormwater system. The hydrologic and hydraulic model will include primary existing stormwater conveyances within the project area simulated to the 25 -year, 24-hour design storm. Drainage basins will be delineated and mapped. Time of concentration and curve calculations will City of Tybee Island Addendum #07 April 30, 2018 Page 2 be in accordance with USDA Technical Release 55 guidance. After model simulations, the water surface elevations will be reviewed in relation to drainage structure frame elevations for areas of flooding known as stormwater system deficiencies. Consultant will review areas of inundation and potential system improvements. A post -development model will be developed and the planned improvements will be modeled to alleviate flooding issues within the drainage area. The Consultant will used Mean High High Water as the tailwater for the model. Deliverables for this phase will include: • ICPR 4, 1 -dimensional model simulating existing stormwater conveyance for the 25 -year, 24-hour design storm. General Study/Reports Phase C. Site Design Lump Sum $8,500.00 Consultant shall prepare drainage improvement plans. These plans shall be submitted to the Owner for review. The site development plans will include: Grading - finish ground elevations, finish contours, and grading information. • Drainage - structure location, pipe route and size, inverts and slopes, and lagoon elevations, including preparation of design calculation. • Water Distribution - no water relocation design is included with this proposal. Should it be required it will be addressed through an amendment to the contract. • Sanitary Sewer - no sewer relocation design is included with this proposal. Should it be required it will be addressed through an amendment to the contract. • Erosion Control - for planned improvements • Profiles - drainage • Construction Details -drainage and erosion control. • Technical specifications for earthwork, drainage systems, and erosion control. • Design calculations - storm drainage Site Design Phase D. Permitting Lump Sum $12,500.00 At this time permitting is not included in this proposal. Thomas & Hutton will prepare the drainage study and construction plans based on the required improvements. The level of permitting effort will vary depending on the amount and types of permits required. Once the improvements have been determined and the necessary permits can be identified, Thomas & Hutton will submit an addendum for the permitting and bid assistance. City of Tybee Island Addendum #07 April 30, 2018 Page 3 E. Meetings Thomas & Hutton will attend one (1) kickoff meeting, and two (2) project update meetings. It is assumed that the first meeting will be at the completion of the drainage study to review the findings and the second will be at or around the 50% completion point of the construction plans. Site Design Phase Time & Expense $1,500.00 A. Exclusions Items not included in the scope of services are as follows: • Permit • Cost Estimating • Construction Services • Determination of Improvements and Associated Costs • Accessibility construction compliance verification • Archaeological survey and report • Wetland, Coastal Marshland delineation, surveys, or permits • Geotechnical investigation or report • Phase One or Phase Two Environmental Assessments • Endangered species survey and report • Off-site work unless specifically covered in the scope of services • Approvals or permits other than those related to the scope of work covered by this contract • Act as an expert witness for legal activities • Georgia Department of Transportation permits or approvals. • Telephones, cable television, gas, and power distribution systems These items can be coordinated or provided, if requested by the Owner in writing. 2. PERIODS OF SERVICE After receipt of a written notice to proceed from the Owner, Consultant will commence and complete work upon a mutually agreed upon schedule between Owner and Consultant. The above fee arrangements are on the basis of prompt payment of our invoices and the orderly and continuous progress of the Project. Project related costs for all printing, travel, reproductions, and materials will be billed as reimbursable expenses. City of Tybee Island Addendum #07 April 30, 2018 Page 4 When approved by both parties this Addendum becomes a legal document and a part of and subject to Terms and Conditions of said Contract. APPROVED: APPROVED: THOMAS & HUTTON ENGINEERING CO. CITY OF TYBEE ISLAN Title: Date: o n V. Giordano, P.E. Project Manager `�/3e//0 Title: City Manager Date: Y/3,07