Michael Marsden, PG, CHg

Principal Hydrogeologist


Contact Information

Phone: (415) 967-6000

Email: mmarsden@rouxinc.com

Location: Oakland, CA

LinkedIn Profile


Hydrogeologic Analysis

Complex Site Assessment and Remediation

Expert Witness

Review/Classification of Investigation and Remediation Costs Claim in Environmental Cost Recovery Disputes

Cost Allocation Between Time Periods, Parties, and/or Sources of Contamination


BS, Hydrogeology - San Diego State University

Michael Marsden, PG, CHg

Principal Hydrogeologist

Michael Marsden is a Principal Hydrogeologist in Roux’s Oakland, California office and has more than thirty years of experience investigating, remediating, and providing technical support to major corporations, attorneys, insurers, private land owners, regulators, and others. He has served as a consulting and testifying expert and technical resource for complex projects and cases. Mr. Marsden’s diverse experience covers environmental pollutants such as solvents, petroleum hydrocarbons, lead, arsenic, chromium, manufactured gas plant (MGP) wastes, and pesticides in soil, groundwater, and sediment. Mr. Marsden has conducted complex hydrogeologic investigations at a number of active and former military installations and industrial sites across California. He has experience evaluating aquifer tests; conducting tidal studies; assessing the effects of saltwater intrusion on groundwater systems; evaluating surface water and groundwater interaction; and identifying contaminant sources. He has also worked over the years on numerous litigation cases. For the past several years, Mr. Marsden has worked with many of the major insurance companies such as AIG, CNA, Resolute, Hartford, Great American, Chubb, and the London market evaluating environmental claims at sites across the country. He works with both carriers and counsel to evaluate various aspects of environmental claims including sources and timing of contaminant releases, incurred and future cost, and cost allocation.

representative projects
  • Technical expert in a case relating to environmental damages arising from the historical operations of a MGP facility adjacent to the Lower Willamette River in Portland, Oregon. Mr. Marsden is evaluating possible allocations associated with the historical site operations. Mr. Marsden is evaluating the nature and extent and timing of contamination in both upland and river sediment. He prepared future cost estimates and conducted categorization of incurred costs and presented at mediation.
  • Technical expert in case involving the classification of investigation, remediation, and operational costs associated with the environmental and litigation activities at a plating facility in Santa Ana, California.
  • Technical expert in case involving the sources and timing of PCE releases from an industrial laundry facility in Seattle, Washington. Additionally, Mr. Marsden evaluated the future remediation costs and prepared alternative future cost analysis. Prepared expert declaration and case was settled just prior to deposition.
  • Technical expert in case relating to environmental damages, possibly arising from the historical operations of a waste water disposal associated with crude oil extraction in the area of Bakersfield, California. Mr. Marsden conducted hydrogeologic characterization of regional aquifers and groundwater geochemistry to assess the nature, extent, and the possible contribution to the brine water in an agricultural area.
  • Project Manager and technical expert in an ongoing case relating to environmental damages arising from the historical operations of a pesticide manufacturing facility and Resource Conservation and Recovery Act (RCRA) permitted solvent disposal facility in San Jose, California. Mr. Marsden has evaluated the scope of work and the various costs associated with conducting a RCRA Facility Investigation (RFI) of the Site and has assisted counsel in forming a potentially responsible party (PRP) group of former owners, operators, and waste generators. Mr. Marsden worked with regulators (DTSC) and PRPs to negotiate a Corrective Action Consent Agreement for the Site.
  • Technical expert for a coverage claim relating to natural resource damages (NRD) arising from historical operations of mercury mining activities in Northern California. Mr. Marsden is responsible for the evaluation of the technical process and the reasonableness and necessity of costs associated with habitat equivalency valuation used in valuing the NRD claim.
  • General Super Plating Company v PKG Equipment, Inc. (2010), State of New York, Onondaga County, Expert Report, testified at trial.

  • American International Specialty Lines Insurance Company v. Chubb Custom Insurance Company (2011), Superior Court of the State of California, County of Los Angeles, Declaration, Deposition, case settled.

  • Block v. Helix and Huddleston v. Haber (2012), Expert report, deposition, case settled.

  • Embee, Inc. fka Embee Plating v. Safeco Insurance Company of America, et al., Orange County Superior Court, Expert report, deposition, case pending.

  • Gardner Family, LLC, et al. v. Crimson Resource Management Corp. (2017), United States District Court, Eastern District of California, Expert report, deposition, case settled.