Agenda - Council Work Session - 07/16/2019 - Special

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CC Special Work Session Meeting Date: 07/16/2019 Title: Staff Update on Water Supply System Request for Proposals Purpose/Background: Purpose: The purpose of this case is to update the City Council on the status of the Request for Proposals (RFP) for treating the City's municipal water supply system for known and emerging contaminants, including but not limited to manganese, and to achieve City Council consensus on the scope of the RFP. Background: Staff is currently developing the draft RFP, and intends to request City Council approval of the RFP on July 23, 2019. Before finalizing the RFP, Staff wishes to discuss and achieve City Council consensus on the scope of the RFP. The current proposed scope of services of the RFP includes three parts. Part 1 focuses on analyzing the source groundwater for the City's municipal water supply system. Part 2 focuses on completing a preliminary design report. Part 3 focuses on preparing a water supply system model. Further details on each part are included below, and will be reviewed by Staff during the work session. 1. Analyze Source Water 1. Analyze aquifer accessibility (where can additional wells be drilled?) 2. Analyze aquifer capacity (can groundwater serve our future needs?) 3. Analyze source water chemistry 1. Identify/inventory known primary contaminants (arsenic, lead, radium, etc.) 2. Identify/inventory known secondary contaminants (iron, manganese, etc.) 3. Identify/inventory emerging contaminants (based on treatment facility anticipated life) 4. Summarize results 2. Prepare Preliminary Design Report 1. Develop plan to select water source (ground vs. surface) based on future demand 1. Northwest metro regional surface water supply study results due January 2020 2. Develop treatment goals (iron and manganese reduction, softening, etc.) 3. Explore treatment options and costs 1. Pressure filters 2. Gravity filters 3. Biological filters 4. Lime Softening 5. RO (Membrane) Softening 4. Summarize advantages/disadvantages of each 5. Select preferred treatment options 6. Develop preliminary centralized treatment facility layout 7. Select preliminary site 8. Calculate estimated costs 9. Identify funding sources 10. Develop preliminary rate structures 11. Develop public education/engagement process 3. Prepare Water Supply System Model 1. Develop and deliver a model for the municipal water supply system Final design of selected treatment processes can then be completed under separate contract after the preliminary