2018/01/24 Council Agenda Packet

• 7, EVERETT STATION PARK-AND-RIDE EXPANSION Agreement with Perteet Inc. - January 2018 • Site Assessment Maps in 11"x17"sheet size with a scale of 1:50,to be included in the Drainage Report. • 4.3 Offsite Analysis • The Consultant will conduct a downstream analysis extending%4 mile downstream/down-gradient of the project limits for each of the Threshold Discharge Areas(TDAs)identified.The downstream analysis will include a review of recent drainage complaint documentation provided by the City(if it exists)and a visual assessment of downstream routes to identify evidence of erosion,flooding,sedimentation,or flow constriction points.A visual above-ground inspection,where practical,will be conducted for each of the downstream drainage conveyance systems associated with the project.Representative photographs will be taken and an assessment of the downstream effects will be performed.The assessment of the downstream effects is to be a qualitative evaluation based upon engineering judgment.The Consultant will prepare a written description of the downstream system conditions and provide a map showing downstream routes.This task does not include detailed hydraulic analysis or computations of the downstream section,but it can be provided as an additional service. The Consultant willperform a visual inspection of the upstream contributing basin area of the site and provide an estimate of the area draining to the site based on available mapping data and site visit observation.This task does not include a detailed review of upstream basin boundary or land use assessment and any detailed hydraulic analysis or computations associated with the upstream basin,but,it can be provided as an additional service. Assumptions: • The site consists of a single TDA and therefore the Consultant will analyze up to one(1)downstream route. • The downstream route field investigation is assuming the Consultant has permission to enter private properties to conduct the work.If the downstream route field investigation requires access onto private property,right-of-entry permissions will be obtained by Everett Transit. Deliverables: • Offsite Analysis Write-up,to be included in a section of the Drainage Report 4.4 Change in Land Use Area Map The Consultant will prepare maps identifying existing and proposed impervious areas.This is used for threshold determination in accordance with the drainage standards,and to identify mitigation needs for flow control and water quality treatment.TDA boundaries,based on site topography and conveyance system configuration,will be identified on these maps.The Consultant will also prepare a summary of area tables for pre-project and post- project conditions.This task includes updating the proposed impervious area maps after 60%plans are complete,if there are significant changes to the site design that warrants an update. Deliverables: - • Change in Land Use Maps and corresponding table of change in land use areas,to be included in the . drainage report.These maps will include: o Existing Impervious Area Maps(1 sheet) • o Proposed Impervious Area Maps(1 sheet) o Tables identifying the different types of impervious surfaces 7 • File location:X:\Everett,City of\Promo Efforts\20170146-Everett Station RIR Expansion\Promo\Business Development\Scope\Everett Transit Parking Lot_Scope 2018-1-IO.doc 8 9 .