Request for Qualifications - Conn Dam Stability Assessment, Spillway Improvements, and Feasibility Alternatives Study

The City of Napa is seeking a highly qualified multidisciplinary engineering consulting team to conduct a comprehensive stability assessment of Conn Dam, design spillway improvements, and develop long‑term feasibility alternatives for reservoir expansion. The effort will be executed in three phases: (1) geotechnical data collection and reporting due Dec 31 2028 to satisfy California Division of Safety of Dams (DSOD) requirements; (2) static and seismic dam‑stability analysis; and (3) alternatives analysis covering spillway upgrades, reservoir raise options, and associated environmental, hydraulic, and economic evaluations. The consultant must possess extensive dam‑engineering experience (≥10 years, ≥3 embankment dams >75 ft), proven DSDS and USACE coordination, and ability to secure and manage federal funding (WRDA, CWIFP). Deliverables include geotechnical data reports, stability analysis reports, integrated deficiency assessments, feasibility alternatives reports, cost estimates, benefit‑cost analyses, and support for permitting and future design. The selection will be qualifications‑based (QBS) with a written SOQ deadline of Oct 29 2026 and a mandatory Q&A cutoff of Oct 20 2026. The overall project is expected to span approximately three years. • Phase 1: Geotechnical investigation, boreholes, CPT, piezometers, lab testing, DSOD report by 12/31/2028. • Phase 2: Dam stability (static, seismic, deformation) and seepage analyses. • Phase 3: Alternatives analysis (spillway widening, fusegates, labyrinth weir, dam raise options, reservoir storage increase). • Required expertise: dam, geotechnical, hydraulic, structural, environmental, cost estimating, and federal funding coordination. • Deliverables: technical reports, design concepts, cost/benefit analyses, regulatory applications, and final feasibility report.