2004/04/07 Council Agenda Packet

6 - 10. No modifications will be made to the existing leachate collection system and pump station. TASKS: 1. Field Survey and Basemaps a. No additional work. 2. Geotechnical Engineering a. Initial coordination, planning, and set up for field exploration (field exploration not performed). b. Conduct engineering analyses for the various components of the 41S` Street embankment extension preload. These components include retaining walls to retain the preload adjacent to the leachate collection system; and connection of the existing LPSB (low permeability soil barrier) with new LPSB. Perform estimates of settlements for the roadway extension and preload, and provide recommendations pertaining to installation of surface settlement plates, set forth a recommended schedule of monitoring of all instruments, and present criteria that may be used to determine when the preloading period may be considered complete. The results of these studies and engineering recommendations will be presented in a geotechnical addendum to the April 9, 2001, final geotechnical report. 3. Storm Drainage System Analysis a. Determine additional stormwater runoff generated from new improvements to the project. Calculate the water quality storm (6-month 24-hour storm) that will be collected and routed to a pump station for discharge. Review pump design and verify that currently specified pumps are adequate to accommodate additional runoff. b. Prepare an overall drainage schematic plan for the conveyance of surface water from proposed improvements. c. Prepare a technical memorandum outlining and recommending improvements as necessary to accommodate additional surface runoff. 4. Temporary Erosion & Sedimentation Control (TESC) Plan a. Update TESC plans and supporting calculations to accommodate additional improvements. 41'Street Overcrossing Page 2 Amendment#11. Attachment A: Scope of Work March 25.2004