RWCF Modifications Project
East Bank Outfall Relocation
Contract Change Order (CCO)-008
Stockton City Council
October 18, 2022
Agenda Item No. 15.4
RWCF Modifications Project
• Original Contract Approach
• Use existing pipelines to convey to existing outfall on west bank
• Allowed for CEQA and permitting to proceed to meet schedule • Install temporary pipelines to serve until new outfall permitted and constructed
• Temporary solution
• New outfall permitting to be completed within 5 years • Purpose of Outfall Relocation Project Contract Change Order (CCO)-008
• Consolidate operations on Main Plant (east side of River) • Avoid cost of temporary pipelines and structures of
approximately $1M
• Allow gravity discharge more than 90% of time
• Comply with NPDES Discharge Permit
East Bank Outfall Relocation Construction
Work No Longer Needed (Temporary)
East Bank Outfall Relocation CCO-008
• Evaluation
• Located formerly-used outfall pipe through levee (circa 1970s) • Considered its use for east bank outfall
• Determined acceptable for EBO
• Updated Design
• Pipe suitable for reuse with lining
• Modify Final Effluent Pump Station (FEPS)
• Reroute effluent pipeline to existing outfall pipe
• Extend existing outfall pipe out and down into river
East Bank Outfall Relocation CCO-008
• Permitting
• Central Valley Flood Protection Board (Flood Board) -complete • Reclamation District 404 - in progress
• Corp of Engineers (COE) - in progress
• Endangered Species Act (ESA): National Marine Fisheries Service (NMFS), Biological Assessment & Biological Opinion
• CEQA-complete
East Bank Outfall Relocation CCO-008
• Remove:
• Construction of pipeline on the west bank of the river • Modifications to the weir control box on the west bank of the river
• Construction of the connection to the existing pipeline under the railroad
• Construction of a new effluent control box at the tertiary plant
• Modify the Final Effluent Pump Station to accommodate gravity flow to the east bank of the river
East Bank Outfall Relocation CCO-008
• Add:
• Construction of effluent pipeline to the east bank of the river • Reinstatement and upgrade of the existing pipe under the east bank levee
• Demolition of the existing apron structure on the east bank of the river
• Construction of a new outfall outlet on the east bank of the river
East Bank Outfall Relocation CCO-008
• Findings (3.68.070):
• Construction interface
• Avoids $1M of temporary work
• Early abandonment of Tertiary Plant
• Assure compliance with June 1, 2024, permit deadline
Recommendations
• Summary of Requested Actions:
• Approve findings pursuant to SMC 3.68.070
• Approve Outfall Relocation Project CCO-008 for $6.8 Million • Incorporate CCO-001 through CCO-007 (Administratively approved)
• Increase Phase 2B contract amount to $206,789,950.31
(Includes CCO-001 through CCO-008)
• Authorize City Manager to execute Outfall Relocation Project CCO-008
• Authorize City Manager to execute payments for direct mitigation; Not to exceed $150,000