Capacity Assurance Report and Wet Weather Alternatives Analysis
City of Millbrae, California

West Yost is completing two projects that are required to address aggressive Consent Decree requirements. The first project provides ongoing O&M support to improve CCTV and cleaning protocols and track various metrics and requirements established in the Consent Decree. West Yost developed a CCTV Inspection Plan, Hot Spot Cleaning Work Plan, Hydraulic Modeling Work Plan, and two Annual Reports, and monitors O&M activities and results on a monthly basis. The second project includes:

  • Capacity Assurance Report: Development of a Capacity Assurance Report, which required development of a fully dynamic hydraulic model to address inflow and infiltration (I/I) in a system with plant inflow limitations; rehabilitation and replacement program
  • Capital Improvement Plan: Creating a Capital Improvement Plan (CIP) to balance I/I reduction with capacity improvements
  • Storage Evaluations: Providing in-system storage evaluations
  • Prioritized CIP: Development of a prioritization tool for the CIP

The InfoSWMM hydraulic model was developed from scratch using a sanitary sewer GIS, and part of the development included QA/QC of the GIS in cooperation with City staff. The prioritization tool developed for the City is a GIS-based risk management analysis that integrates CCTV data, O&M data, and capacity results in order to prioritize pipelines for inspection, rehabilitation, or replacement in a way that maximizes the returns the City sees for its expenditures.