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

Vice President

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. Yeh oversees geohydrological investigations, groundwater modeling projects, and environmental and watershed analyses for numerous clients throughout California. [read more]

Brian Villalobos, PG, CHG, CEG

Principal Geohydrologist

Brian has more than 25 years of professional experience in environmental geology and hydrology throughout California. [read more]

Chris Coppinger, PG, CHG

Senior Geohydrologist

A member of the GEOSCIENCE team since 2005, 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

Senior Geohydrologist

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

Project Geohydrologist

Adam is a project geohydrologist whose responsibilities include groundwater basin evaluations, artificial recharge, groundwater modeling, groundwater quality investigations, geothermal investigations and project management. [read more]

Kapo Coulibaly, Ph.D.

Project Geohydrologist

Dr. Kapo Coulibaly has 15 years of focused experience with geologic and geohydrologic investigations and groundwater modeling. [read more]

Nathan Reynolds, PG

Project Geohydrologist

Nathan is a project geohydrologist who has extensive experience in geohydrologic investigations, groundwater quality studies and artificial recharge projects. [read more]

Lindsay Swain, PG, CHG


Lindsay has more than 40 years’ experience in groundwater basin evaluations, artificial recharge, groundwater quality investigations, subsidence and sustainability issues. [read more]

Meridee Williams, MBA

Chief Financial Officer

Meridee is the chief financial officer who is responsible for the oversight of projects, financial operations and business affairs. [read more]

David Bauer

Technical Illustrator, GIS Analyst

David has over 28 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.

Project Administrator

Dawn serves as our project administrator with responsibilities that 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

Tiffany Jensen

Office Manager

Tiffany is the office manager who 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.

Staff Geohydrologist I

Seth is a staff geohydrologist whose 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.

Staff Geohydrologist I

Edward is a staff geohydrologist with responsibilities that include  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

Staff Geohydrologist I

Leo is a staff geohydrologist whose responsibilities include 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

Chindamony Pak

Staff Geohydrologist I

Chindamony is a staff geohydrologist with experience assisting in geohydrologic investigations, groundwater quality studies, well assessments, water well test drilling programs and the supervision of water well projects.

B.A., Human Development, California State University Long Beach, 2007 B.S., Geology, California State University Long Beach, 2015

Coral Shaw

Staff Geohydrologist II

Coral is a staff geohydrologist 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

Staff Geohydrologist I

Si Si is a staff geohydrologist with 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.

Staff Geohydrologist I

Amanda is a staff geohydrologist with 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

Staff Geohydrologist III

Lauren is a staff geohydrologist who has experience with 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

Staff Geohydrologist II

Logan is a staff geohydrologist handling 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