2011/10/05 Council Agenda Packet

• l Phase 1 — Confirmation of Concept, Infrastructure Assessment and Project Definition Task 200 — Alternatives Analysis, Modeling, and SD Bypass Pipeline Alignment Recommendation The purposes of this task are to receive and review data, previous studies and model outputs completed by Otak, Inc. for the City; to generate alternatives for routing of the new SD bypass pipeline; to model alternatives; and to select a preferred alternative alignment for the recommended improvements. Assumptions: • For this Scope of Work, the project area is limited to the area shown in Exhibit A-1. • The Consultant will utilize and rely on the SWMM model provided by the City. The model will be assumed to be calibrated with "record drawing" information already incorporated. The model will focus on sewer flows in the Sewer "M" area, and will not include analysis of the downstream outfall or interceptor. • The Consultant will use and rely on GIS data provided by the City for purposes of general location of surface improvements. The Consultant may recommend performance of spot elevation and location data checks by the Consultant's field survey subconsultant, limited in effort by the allowance shown in this Scope of Work. • Building finished floor or basement elevations on private property will not be surveyed and all field data required for design can be obtained within City right-of-way or easements, except as follows: For approximately 60 of the 190 properties identified in Figure 4-21 of the Secondary Study Area Stormwater Bypass System Alternative 9 (Exhibit A-2) as having virtual basements. The City will provide notification of property owners and arrange for access by surveyors for making appropriate measurements. • The City will conduct a pre-study survey to identify those residents having basements with plumbing and will provide historical information on known basement flooding events. The City will provide a list of these residences, which will serve as the basis for those properties whose basements will need to be surveyed. • A maximum of six conveyance alternatives will be analyzed for eliminating potential for basement flooding. • The City will provide storrn events to be used in this analysis. Model runs will be performed for up to six storm events, which will be selected during the project kick-off meeting. • The City will handle all permitting and regulatory issues and approvals relating to this effort. Activities: Data Review. The City will provide copies of previous studies and models completed by Otak, Inc. for the project area. The Consultant will review utility model data, the City's GIS inventory data, and available and applicable reports. The Consultant will review and provide written comments on the information as required in order to clarify the basis of the work for Task 200. September 2011, r3.0 Page 5 of 10 Jacobs Engineering Group Inc. 17