Our Team Bios
Dennis E. Williams, Ph.D., PG, CHG
Founder and President
Dr. Dennis Williams is the founder and President of GEOSCIENCE. He has more than 45 years’ experience in groundwater hydrology, directing geohydrologic investigations locally and globally.[read more]
Mark Williams, Ph.D., PE
Dr. Mark Williams is Vice President of GEOSCIENCE. His responsibilities include oversight of water quality and engineering portions of GEOSCIENCE projects. [read more]
Johnson Yeh, Ph.D., PG, CHG
Principal Geohydrologist & Groundwater Modeler
Dr. Johnson Yeh oversees geohydrological investigations, groundwater modeling projects, and environmental and watershed analyses for numerous clients throughout California. [read more]
Chris Coppinger, PG, CHG
Chris’ work includes groundwater basin evaluations, well siting investigations, artificial recharge and conjunctive use studies and desalination feedwater supply studies. [read more]
Terry Watkins, PG, CHG
Terry‘s expertise includes well design, construction, testing and development. He also has experience in the management and supervision of water well projects including siting, design, aquifer pumping test analyses and well construction. [read more]
Adam Norris, PG, CHG
Adam’s responsibilities include groundwater basin evaluations, artificial recharge, groundwater modeling, groundwater quality investigations, geothermal investigations and project management. [read more]
Alexander has experience in hydrologic investigations, groundwater well development and field data collection.
B.S., Geology, California State University Fullerton, 2017
David Barnes, M.Eng.
David has 8 years of professional experience working in the water resources, water supply and mining sectors. His experience includes numerical modeling of surface and groundwater systems, design and construction of water supply and injection wells for fresh, brackish and seawater RO facilities.
B.S., Hydrology and Water Resources, University of Arizona Tucson, 2008
M.Eng., Civil and Environmental Engineering, MIT, Cambridge, 2009
Technical Illustrator/GIS Analyst
David has over 29 years of experience in the water industry with involvement in the production of presentation and technical graphics. He serves as our GIS coordinator whose responsibilities include the organization of all GIS activities, database management and graphic creation within our technical reports.
B.A., Physical Geography, Humboldt State University, 1988 with concentrations in Water Resource Policy and Natural Resources
Dawn Cooper, M.A.
Dawn’s responsibilities include office management and the administration of the timesheet and billing system. She is also responsible for the administration and implementation of our CRM system for Business Development, where she works closely with the Director of Marketing. She also works on special projects in the office along with supporting the GEOSCIENCE GIS team.
B.A., Geography, Kent State University, 2001
M.A., Geography, Ohio University, 2003
Steven Davey, M.S.
Steven has a broad range of experience including groundwater modeling, field data collection and test results analysis.
B.S., Geological Sciences, University of Michigan, 2011
M.S., Geology, Indiana University, 2016
Phillip has experience in California and international water policy, as well as, a background in data and spatial analyses of environmental issues.
B.A., Environmental Studies, Bates College 2016 with a concentration in Environmental Economics
Edween Hernandez, M.S.
Edween’s experience includes geohydrologic investigations, groundwater well development and construction oversight, field data collection and test results analysis.
B.A., Education, University of California, Riverside, 2012
M.S., Geology, California State University, Fullerton, 2017
Tiffany is responsible for organizing work assignments including meeting deadlines, monitoring report production and office administration. She also works closely with the Director of Marketing on proposal creation, marketing graphics and manages the accounts payable for our company.
Certificate of Paralegal Studies, InterCoast Colleges-West Covina, 2005
Seth Kuiper, M.S.
Seth’s responsibilities include field work, geohydrologic investigations and groundwater quality studies. He has also been involved with data collection and analyses on various projects.
B.S., Geology, Calvin College, 2010
M.S., Geoscience, Western Michigan University, 2015
Edward Linden, M.S.
Edward’s experience includes geohydrologic investigations, GIS mapping, groundwater quality studies and lab management. He also has experience with well assessments, water well test drilling programs and has supervised on water well projects.
B.A., Geology, Occidental College, 2011
M.S., Geosciences, Florida International University, 2015
Leo Liu, M.S., EIT
Leo has expertise in groundwater flow and solute transport modeling, as well as, geohydrologic investigations. He also has experience using GIS applications.
B.S., Environmental Engineering, Tianjin Institute of Urban Construction, 2010
M.S., Environmental Engineering, University of Southern California, 2013
Wesley Massoll, M.S.
Wesley’s experience includes geohydrologic investigations, groundwater well development and construction oversight, field data collection and test results analysis.
B.S., Geology, University of North Carolina Wilmington, 2012
M.S., Geology, University of North Carolina Wilmington, 2017
Coral is involved in a variety of projects, including geohydrologic investigations, groundwater quality studies, well assessments, water well test drilling programs and the supervision of water well projects.
B.S., Geology, California State University Fullerton, 2012
Si Si, M.S., EIT
Si Si has experience in groundwater flow and solute transport modeling, geohydrologic investigations and GIS applications.
B.S., Environmental Science, Ocean University of China, 2010
M.S., Environmental Engineering, University of Southern California, 2013
Amanda VanHaitsma, M.S.
Amanda has expertise spanning the spectrum of groundwater services, including geohydrologic investigations, groundwater modeling, water quality studies, desalination feasibility and groundwater wells.
B.A., Hydrogeology, Environmental Studies, Central Michigan University, 2014
M.S., Geosciences, Virginia Polytechnic Institute and State University, 2016
Lauren Wicks, M.S., GIT
Lauren’s expertise includes groundwater flow and transport modeling, geohydrologic investigations, groundwater basin and water quality studies. She has also been involved with artificial recharge projects, litigation projects, technical report preparation and GIS applications.
B.S., Integrated Earth Studies/Geology, California State Polytechnic University Pomona, 2009
M.S., Hydrology, University of Idaho, 2011
Logan Wicks, M.S., GIT
Logan handles groundwater quality evaluations, well siting investigations, data collection and analyses, and remediation and water supply studies.
B.S., Geology, California Polytechnic University Pomona, 2010 B.S., Biology, California Polytechnic University Pomona, 2010 M.S., Geology, California Polytechnic University Pomona, 2014
Meijing Zhang, Ph.D.
Meijing has modeling expertise in groundwater flow, integrated groundwater-surface water exchange, and land subsidence. She has additional experience in GIS applications and hydrologic investigations.