1 – Evaluate Opportunities and Constraints

1. Miller-Walker Basin Stormwater Retrofit Planning Study Retrofit Evaluation Process Framework • 1 – Evaluate Opportunities and Constraints • Review available data, planning information, as-built drawings, etc. • Interview County and municipal staff • Assess infiltration feasibility using available data • Conduct HSPF modeling to quantify sub-basin retrofit needs • Develop GIS maps illustrating retrofit opportunities and constraints GIS maps of opportunities and constraints • 2 – Identify Preliminary Retrofit Opportunities • Identify candidate retrofit opportunity areas (map & summary table) • Perform preliminary screening of candidate opportunities • Conduct driving/walking tour of screened candidate opportunities • 3 – Develop, Assess & Rank Retrofit Concepts • Evaluate feasibility, benefit, and risk criteria for screened candidate opportunities • Rank projects (Level I Ranking) • Select top top-ranked projects for further development 80 identified opportunity areas Public Input 30 preliminary planning-level retrofit concepts • 4 – Develop Concepts and Prioritize Projects • Conduct field evaluation • Prepare preliminary planning-level retrofit concepts and cost estimates • Run HSPF model to estimate flow control benefits • Prioritize projects (Level IIRanking) 3 to 5 project pre-designs • 5 – Preliminary Engineering • Refine preliminary planning-level retrofit concepts and estimates • Prepare preliminary engineering reports to assist with grant funding applications for top priority projects • Prepare retrofit plan implementation report (outline strategy for long-term implementation)