About TJA

TJA Founder and Principal, Thomas M. Johnson, PG, CHG, has more than 40 years consulting and research experience involving environmental assessment and remediation, water resource assessment, groundwater flow, contaminant fate and transport, regulatory interaction, and environmental liability allocation. Mr. Johnson is a Licensed Professional Geologist and Certified Hydrogeologist in California, and a Licensed Professional/Registered Geologist in Arizona, Florida, Illinois, Indiana, Pennsylvania and Wisconsin. He has provided expert testimony in both state and federal courts, legislative hearings, and alternative dispute resolution hearings, and has lectured extensively in the U.S. and internationally for universities, state and federal agencies, and professional organizations.

Mr. Johnson is Past President of the California Groundwater Resources Association, and former Chair of the Board of Directors of the National Groundwater Association, Association of Groundwater Scientists and Engineers. He also has been appointed to National Academy of Sciences/National Research Council Panels to evaluate state and local groundwater protection programs for the U.S. Environmental Protection Agency, and to assess innovative technology decision-making programs for the U.S. Department of Energy.