Andrew J. Halmstad, P.E.

Senior Consultant

Bio
Relevant Experience
Education & Credentials
Insights & News

Bio

Mr. Andrew Halmstad is an engineer with 14 years of consulting experience focusing on environmental remediation and cost allocation of contaminated sediments, groundwater, and soils. His specific skills include reviewing and summarizing results of ongoing environmental investigations, leading source control and remedial design activities, and directing data analysis for site characterization and remedial activities. Mr. Halmstad has supported and led numerous field operations, including site investigations, in situ remedial treatment application, aquifer testing, remediation system operations maintenance and monitoring, and sampling of soil, groundwater, and stormwater. He also has experience planning, managing, and conducting complex environmental investigations; analyzing remedial alternatives; conducting feasibility studies; and providing oversight of remedial measures.

Relevant Experience

Remedial Design

Sediment Remedial Design at Active Steel Mill, Portland, Oregon — Serving as senior engineer for sediment predesign investigations and the remedial design of a 2-mile stretch of a 10 mile, multiparty Superfund sediment megasite. Leading multiple stages of project area investigations to determine the nature and extent of chemicals of concern (COCs)—including PCBs and dioxins—in sediment, porewater, and other media. Planning remedial design, construction implementation, and long-term monitoring elements in consideration of conservative regulatory guidance and in evolution with trustee and performing-party feedback. Leading development and evaluation of supplemental predesign investigation elements, including sediment footprint delineation and paired-porewater-sediment sampling, to assess buried contamination stability and design of capping areas. Modeling chemical migration with CapSim using site-specific portioning parameters.

Evaluating and determining appropriate remedial actions for the site using sediment transport modeling, data collection sequencing, evaluations of bathymetric changes, upland data characterization, considerations of background conditions and potential upstream contaminating activities, and use of other data-driven evaluations to identify appropriate project area COCs and develop an adaptable cleanup action. Supporting the client in a collaborative, remedial-design party group addressing evolving regulatory remedial design guidance. The work area adjoins five properties and necessitates negotiated access agreements, coordination for sample collection and split samples, and overall data sharing that affects the design.

Sediment Superfund Site Remedial Investigation and Feasibility Study Implementation, Jacksonville, Florida — Project manager for a sediment focused remedial investigation in an intertidal creek adjoining the St. Johns River in Jacksonville, Florida, focused on the nature and extent of a multitude of chemicals (e.g., PCBs, pesticides, volatile organic compounds [VOCs], metals). Implementing the agency-approved RI/FS work plan requiring multimedia data collection (sediment, surface water, porewater, benthic invertebrate, and fish tissue), human health and ecological risk assessment, and culminating in a feasibility study for a partially submerged, tidally influenced wetland.

Soil and Groundwater Remediation Support at a Chemical Distribution Facility, Santa Ana, California — Project manager for multimedia chlorinated solvent remediation project with several active remediation components. Responsible for leading multiple ongoing project components including oversight of operations and maintenance of a multiphase groundwater treatment program at a chemical distribution facility; data analysis and review in support of ongoing remediation reporting at the facility; and preparation of semiannual groundwater monitoring and remediation reports summarizing periodic sampling and analysis of resulting data. Recent work included preparation of an agency-approved remedial action plan for accelerated treatment of soil and groundwater to achieve site closure and implementation of initial phases of the plan.

Operations and Maintenance, Engineering, and Technical Support, Steel Mill, Portland, Oregon — Supporting the Principal-in-Charge for a multiyear source control and remedial investigation and feasibility study at an active steel mill. Work includes site characterization, risk management, and implementation of remedial actions to prevent soil, sediment, and stormwater impacted with PCBs and metals from adversely affecting the Portland Harbor Superfund site. Supported pilot testing-level implementation of a proposed stormwater treatment system including field support, data analysis, and evaluation to support full-scale design and implementation. Serving as engineer of record for a focused feasibility study evaluating surficial extent of COCs potentially requiring remedial action.

Superfund Remediation Process Optimization, La Marque, Texas — Supported the lead project engineer with evaluation of an existing groundwater treatment system to develop recommendations for streamlined unit processes. Supported migration of an aging programmable logic controller system to a modern system. Developed a robust network setup that allows for controlled local and remote access by multiple users. Currently supporting the evaluation of enhanced separation of dense nonaqueous-phase liquid for reduced operations and maintenance time/cost.

Former Vapor Cleaners, Monterey, California — Project manager for ongoing remediation and monitoring of volatile organic compound (VOC) contamination at a former dry cleaner site. Provided field oversight of an in situ enhanced bioremediation injection program targeting VOCs in a shallow, sandy, coastal aquifer.

Yosemite Slough Remedial Design, San Francisco, California — Provide direct support to the engineer of record for an EPA non-time-critical removal action of lead- and PCB-contaminated sediments at the Yosemite Slough Superfund site. Project elements include sediment dredging, capping, and natural attenuation. The design includes multiple proof-of-concept studies, as well as development of plans and specifications for construction.

Former Gasoline Fueling and Service Stations, Oregon — Project manager for an ongoing, multisite project involving ongoing remedial activities at former fueling and service stations throughout the state of Oregon. Project work has involved groundwater monitoring, well decommissioning, and contractor oversight at both current and former fueling stations.

Stormwater Management

Former Chemical Manufacturing Facility, Portland, Oregon — Provided technical support in implementation of project plans and specifications for construction of stormwater source control measures, including capping of areas of known contamination, decommissioning of the current site stormwater collection system, and construction of drainage channels, detention basin, and sand filter prior to discharge to the river. Provided construction oversight, including coordination with contractor, client, and onsite facility personnel. Currently assisting with monitoring of the implemented stormwater measures to assess performance, optimize treatment efficiencies, and conduct ongoing operations and maintenance activities. Duties include routine site visits for operations maintenance and management of the existing system, periodic sampling, and data collection.

Sediment Investigation

Source Control and Sediment Cleanup Multiparty Allocation Support, Portland, Oregon — Project manager overseeing multiple active tasks and providing technical support related to source control activities and allocation of CERCLA cleanup and natural resource damage costs. Researched historical records, conveyance system maps, industrial operations, soil and sediment chemistry, and fate and transport. Researched other nearby properties. Managed development of memoranda and research tasks, including operational and drainage history, sediment transport modeling, and forensic evaluations. Compiled and synthesized relevant information to respond to disclosure questionnaires and supplemental information requests. Evaluated natural resource damage settlement offers relative to sediment chemistry, sources, and operational history, and prepared associated documentation. Communicated findings to facility staff and attorneys, and participated in a collaborative team with attorneys.

Multiparty Allocation Related Expert Report and Rebuttal Support, San Francisco, California — Support the potentially responsible party group in developing a detailed historical understanding of a combined sewer network and its connection to a contaminated slough in San Francisco, ultimately resulting in preparation of an expert report. Project work involves the review of historical construction schematics and previous environmental site assessments (sediment investigation and contaminant transport, including PCBs), development of a timeline of combined sewer conveyance routes, and mass loading calculations to support a mass balance–based allocation approach.

Mission Bay Ferry Landing Project, San Francisco, California — Project manager for design of an engineered cap to address contaminated sediments at a ferry terminal. Responsible for modeling breakthrough in the cap, engineering, drawings, specifications, costing, and close coordination with the dredging and ferry terminal designers.

Soil Sampling Support at a Former Zinc Smelter Site, Blackwell, Oklahoma — Provided field support for drilling and soil sampling activities to characterize subsurface conditions at the site.

Hydrologic Modeling

Permitting and Hydrologic Assessment of an Exploratory Large Open-Pit Gold Mine, Nevada — Supported a comprehensive hydrologic assessment of a property in an advanced stage of mineral exploration. Provided background data research and compilation, logistical planning, and fieldwork assistance for a multistage hydrologic test program. The results from the hydrologic assessment were used to evaluate project risk and support additional data collection efforts to reduce risk uncertainty.

Regulatory Compliance

NPDES Industrial Stormwater Permitting and Compliance Support, Portland, Oregon — Ongoing compliance support consisting of monthly stormwater inspections, NPDES reporting assistance, and review of best management practices at multiple industrial sites in the metropolitan area.

Litigation Support

Litigation and Technical Support for a Chemical Distribution Facility, Santa Ana, California — Reviewed reports and provided litigation support including preparation of material to assist with deposition of both plaintiff and defendant experts. Provided oversight of ongoing operations and maintenance work at the facility. Provided data analysis and review in support of ongoing remediation reporting at the facility. Prepared semiannual groundwater monitoring and remediation reports summarizing periodic sampling and analysis of resulting data.

Education & Credentials

M.S.C.E.E., Water Resource Engineering, Portland State University, Portland, Oregon, 2011

B.A., Physics, Lewis & Clark College, Portland, Oregon, 2007

Professional Engineer, Washington (License No. 23026933)

Professional Engineer, Oregon (License No. 085089PE)

Professional Engineer, Texas (License No. PE 156333)

Continuing Education

DOT Hazardous Materials Transportation and Security Awareness Training (2013)

OSHA 40-Hour HAZWOPER

OSHA 8-Hour HAZWOPER Refresher

OSHA 8-Hour HAZWOPER Supervisor

Mine Safety Health Administration Training (2012)

First Aid/CPR/AED Certified

Insights & News

Market Update

The Benthic Zone (September 2025 Edition)

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Resources

Technical Impracticability Waivers: An Underutilized Tool for Managing Sediment Sites

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Videos

Emerging Contaminants in Stormwater: Webinar

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