The City of Petaluma requires Geotechnical and Environmental Engineering Services to evaluate subsurface conditions at the project site located at the corner of North McDowell Boulevard and Old Redwood Highway. The scope of work is vital to the design of the PPSF, ensuring the facility meets all standards for seismic resilience and environmental safety.

• Subsurface Investigation & Exploration: Perform systematic subsurface exploration through borings and sampling to define site-specific geotechnical parameters. Borings must be sufficient in depth and number to characterize the building footprint and site improvements.
• Roadway and Pavement Analysis: Evaluate existing and proposed pavement sections at the intersection of North McDowell Blvd and Old Redwood Highway. This includes determining "R-values" and traffic index analysis to support emergency vehicle traffic loads.
• Seismic Design Parameters: In accordance with California Building Code (CBC) 1617A, the report must provide ground motion recommendations, including MCE (Maximum Considered Earthquake) spectral response accelerations for an Essential Services Facility.
• Geologic Hazard Evaluation: Assessment of potential geologic hazards including seismic-induced liquefaction, lateral spreading, and expansive soil conditions that could impact the foundation or utility infrastructure.
• Stormwater and Infiltration Compliance: Conduct field permeability testing to provide infiltration rates for the project's stormwater management system, adhering to Low Impact Development (LID) standards.
• Environmental Soil Screening: Conduct a screening-level assessment for potential soil and groundwater contamination based on historical site use, analyzing for heavy metals, petroleum hydrocarbons, and VOCs.
• Foundations and Construction Guidance: Provide recommendations for foundation types (e.g., shallow vs. deep), allowable bearing pressures, settlement estimates, and specific earthwork guidelines for grading, fill placement, and compaction.
• Corrosion Analysis: Laboratory testing of soil samples to determine chemical properties, including pH, minimum resistivity, and sulfate/chloride content, to mitigate risk to buried metal and concrete structures.