Brown and Caldwell Inc. 3/9/2022 Amendment 1

• Participate in workshops. • Supply relevant operations data, wholesale purveyor agreements, and control strategies. Task Assumptions • Recommendations will provide the basis for the control strategy and design of the control valves in Portal 4. • Recommendations will be developed through a review of supplied documents by others and BC's ongoing work on the Finished Water Pump Station and through the associated workshops with the City. No additional hydraulic modeling or numerical analysis will be needed. Meetings • North Corridor operations workshop. Assume attended by three BC staff, with a duration of two hours, conducted via video conference. • North Corridor recommendations workshop. Assume attended by three BC staff, with a duration of two hours, conducted via video conference. Work Products • North Corridor Flow Controls Evaluation, Alternatives, and Recommendations technical memorandum, draft and final. Task 300 Basis of Design Activities/Approach: BC will perform evaluations to finalize all major design decisions and provide design criteria and equipment selections for the Portal 4 improvements. This information will be presented in a Basis of Design Report. Amendment 1 updates to Task 300 account for work completed under the basis of design phase for additional project elements not accounted for in the original scope of work. This work includes the installation of isolation valves and vaults on transmission lines 2, 3, and 4 and the addition of a security fence around the Portal 4 structure as described in the BODR. The addition of valves and a security fence also required development of draft scopes of work for survey and geotechnical subconsultants which were presented as appendices in the BODR. This task encompasses work completed by the process mechanical discipline, civil discipline, and design manager for the added project elements at Portal 4. Specific task activities include: • Conduct site visit to verify field conditions and interview Plant Staff to confirm scope of improvements needed. • Evaluate suitability of re-using existing 2" conduit and existing cable vs new conduit and/or cable and review potential alternative route(s)for upgrading buried electrical service to Portal 4. • The Portal 4 design package will include the following improvements: • Replace/repair corroded structural elements.Analyze structure for required repairs. • Remove rust stains. Evaluate coating options. • Replace door • Remove and seal off louver openings • Cover open channel and vent to atmosphere • Replace/upgrade electrical equipment • Improve electrical service to Portal. • Add mechanical ventilation system for the room and/or channels (assume no heating required) • Install flow control valves with remote monitoring and operation. Evaluate condition and capacity of existing valves, actuators,telemetry, and PLC system. Page 4 of 13