Thomas D Gillespie, P.G. Expert Witness
Curriculum Vitae

Contact this Expert Witness

  • Company: Gilmore & Associates, Inc.
  • Phone: 1(610) 216-9485
  • Cell: 1(610) 216-9485
  • Website:

Specialties & Experience of this Expert Witness

General Specialties:

Geology and Environmental

Keywords/Search Terms:

Groundwater, Hydrogeology, Geology, Geo-Hazards, Mining, Stormwater, Oil & Gas, Bedrock Aquifer, Groundwater Contamination, Environmental Forensics, Environmental Evaluation, Environment, Water Resources, Water Supply, Karst, Karst Geology, Karst Hydrogeology, Sinkholes


M.S., Rutgers University; B.S., Rutgers University; B.A., The College of New Jersey

Years in Practice:


Additional Information

Expertise in hydrogeology, geology and environmental forensics with a specialization in groundwater flow and contaminant transport in fractured bedrock aquifers. Mr. Gillespie's technical expertise is complemented by an industry insider’s savvy of corporate needs and operations and the regulatory acumen of a former agency reviewer and bureau official. He is a published researcher in hydrostructural geology and karst hydrogeology, an adjunct university professor of geology and a frequent provider of continuing professional education courses. Mr. Gillespie is routinely invited to speak on matters of earth, environment and energy to government committees, national business organizations and educational institutions. He developed and leads a geoResource Risk Reduction practice, specializing in strategic representation in regulatory and legal venues. Mr. Gillespie has provided litigation support, testifying expert services, expert regulatory negotiation support and public representation on a wide range of geologic, hydrogeologic and environmental matters. His recognition as a geologic expert was acknowledged when he was selected by his peers to be the representative of the community of licensed professional geologists on the Pennsylvania Registration Board for Professional Engineers, Land Surveyors and Geologists in which he served two terms as board President. He represented Pennsylvania in the National Association of State Boards of Geology, where he was elected to the executive committee and still serves as a subject matter expert in hydrogeology, structural geology and engineering geology. Mr. Gillespie's unique insights into environmental management have been recognized by multiple organizations which retain him to provide continuing professional education to environmental professionals on strategic environmental managers and consultants. Mr. Gillespie currently offers advanced continuing education courses in geology, hydrogeology, and in regulatory and expert representation through the Pennsylvania Council of Professional Geologists, Continuing Professional Education Services, Inc,, The Marcellus Shale Coalition, the Pennsylvania Aggregates and Concrete Association, Pennsylvania Independent Oil and Gas Association, and the NJ Bar Association. He was a member of the boards of the Pennsylvania Council of Professional Geologists and The Marcellus Shale Coalition, in both of which he served on committees dealing with continuing professional education, regulatory review and standards of practice. He has been invited to provide testimony on geologic, hydrogeologic, environmental, regulatory purview, permitting reform and geologic hazards to the Pennsylvania Senate and General Assembly. Mr. Gillespie has provided public representation and expert testifying services in a wide range of geologic, hydrogeologic and environmental matters ranging from stormwater, geologic hazards, oil and gas exploration and development, groundwater supply, groundwater contamination, watershed management, stream restoration, and state and federal site remediation cases.