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Tonia Johnson

Senior Geologist

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Tonia O’Brien has over a decade of experience helping municipalities, attorneys, developers, and industrial and energy clients solve complex problems. Her work as a geologist includes a unique blend and depth of services, including surface-water and groundwater hydrology, water supply, engineering support, and environmental due diligence as well as environmental investigation, remediation, and redevelopment. For small- to large-scale investigation and remediation projects, Tonia is responsible for coordinating, overseeing, and managing Phase I environmental site assessments, subsurface investigations, geologic and hydrogeologic investigations, remedial design, and geotechnical evaluations.


(952) 832-2775


Professional Geologist (CA, MN, WI)


BA, Geology, University of St. Thomas


Barr Engineering Co.
4300 MarketPointe Drive
Minneapolis, MN 55435

Phone: 952-832-2600
Fax: 952-832-2601
Toll free: 800-632-2277