Reliable basin management
Unbeatable expertise across all groundwater resource management areas
INDUSTRY
Why work with us
We are trusted advisors to water providers, and enable reliable development of wells, groundwater models and basin management.
AT A GLANCE
40 years experience
Developing models, designing wells, and managing groundwater basins with excellent results
Scientific + Legal Compliance
Solving new and challenging problems, with decision certainty and dependable outcomes
Qualified + certified staff
Qualified, degreed, and professionally licensed geologists, engineers, and modelers
Reliable basin management
Unbeatable expertise across all groundwater resource management areas
40 years experience
Developing models, designing wells, and managing groundwater basins with excellent results
Scientific + Legal Compliance
Solving new and challenging problems, with decision certainty and dependable outcomes
Qualified + certified staff
Qualified, degreed, and professionally licensed geologists, engineers, and modelers
Robust, compliant basin management
Providing reliable groundwater basin management
For 45 years, our basin-wide models have predicted the impact of groundwater pumping and future water augmentation projects. Our sustainability plans are in place in some of the most challenging basins.
Geoscience supports the entire Sustainable Groundwater Management Act (SGMA) process, from developing Groundwater Sustainability Plans (GSPs) and managing stakeholders to implementing groundwater management actions.
Click & Get Wiser
40 years experience developing modeling and well design methods
Every day, we make sure the public has access to a high-quality water supply with a reliable infrastructure.
We are a leader in developing standard practices for groundwater modeling and well design, based on science and practical experience. A full service organization, we leverage accurate and reliable tools that are legally defendable.
OUR CUSTOMERS
Experience + Technology to Solve Challenging Problems
Get the Science Right
We solve challenging problems for water providers, with certainty of outcome and dependable results verified with field data. Deep expertise meets current and future planning and operating needs. Trusted advisors in development of well infrastructure, groundwater models and basin management, we use accurate and legally defendable tools for our work.
Highly qualified, degreed staff building trusted relationships
We are geologists and engineers from top universities, many have advanced degrees and are professionally licensed. The highly qualified staff keeps learning and developing through working on rich and varied projects. We get the science right, and in the process build lasting long-term relationships.
Mark Williams
CEOMark Williams
CEO
Mark Williams, PhD, PE
Dr. Mark Williams is Geoscience’s CEO. With his unique background combining engineering and geology, Mark brings deep expertise and experience from his 25+ years working in water utility engineering and groundwater quality.
Prior to joining Geoscience in 2014, Mark served as an Engineer with the Process Development Team at the Metropolitan Water District, and subsequently consulted on a variety or water treatment projects including the Doheny Desalination Project and numerous groundwater treatment projects. Mark has presented and published extensively in the areas of water treatment engineering and water quality.
Dennis Williams
President/Principal GeohydrologistDennis Williams
President/Principal Geohydrologist
Dennis Williams, PhD, PG, CHG
Dennis Williams is the founder and president of Geoscience Support Services Inc. (Geoscience) He has more than 50 years of experience in groundwater hydrology and has directed more than 2,000 hydrogeologic investigations and groundwater models and overseen design and construction for more than 1,000 groundwater production and monitoring wells. Dennis has been a consultant to the United Nations and several foreign governments, is a research professor at the University of Southern California’s Civil and Environmental Engineering Department and has taught graduate level courses in hydrogeology and ground water modeling since 1980.
Johnson Yeh
Principal ModelerJohnson Yeh
Principal Modeler
Dr. Johnson Yeh is a principal and lead groundwater modeler at Geoscience. During his more than 27 years of career, he has been involved in the project management of the firm’s groundwater modeling efforts, including some of its most high-profile geohydrologic investigations, groundwater basin/water quality studies, and artificial recharge projects. Dr. Yeh also possesses a broad knowledge of GIS tools utilized in support of modeling work and oversees Geoscience’s GIS staff members.
Dr. Yeh spearheads the generation and quality control of technical documents and technical presentations to both clients and regulators, including leading training and workshops on the use of models to the USGS and USEPA.
Terry A. Watkins
Principal GeohydrologistTerry A. Watkins
Principal Geohydrologist
Terry Watkins, PG, CHG
Terry has more than 19 years of experience in a variety of groundwater projects, including geohydrologic investigations, groundwater quality studies, artificial recharge projects, site feasibility and test drilling programs, sea water desalination programs, in addition to water well design, construction management, and supervision. Terry has completed more than 350 well projects over the course of his career. He is currently a Senior Geohydrologist at Geoscience and manages our well construction group, overseeing project aspects ranging from site evaluation and selection, preliminary well design, development of technical specifications, final well design, aquifer pump test analysis, development of well rehabilitation programs, and providing construction management services. Terry has performed project management and well construction management and supervision on several multi-well projects throughout California including municipal water supply wells, ASR wells, injection wells, and monitoring wells.
Terry is an active member of the American Water Works Association (AWWA). He serves as an alternate member of the Well Standards Committee (Standard A-100) as well as the California-Nevada Section of the AWWA and is a frequent speaker on well related topics.
Mark Williams
CEO
Mark Williams, PhD, PE
Dr. Mark Williams is Geoscience’s CEO. With his unique background combining engineering and geology, Mark brings deep expertise and experience from his 25+ years working in water utility engineering and groundwater quality.
Prior to joining Geoscience in 2014, Mark served as an Engineer with the Process Development Team at the Metropolitan Water District, and subsequently consulted on a variety or water treatment projects including the Doheny Desalination Project and numerous groundwater treatment projects. Mark has presented and published extensively in the areas of water treatment engineering and water quality.
Dennis Williams
President/Principal Geohydrologist
Dennis Williams, PhD, PG, CHG
Dennis Williams is the founder and president of Geoscience Support Services Inc. (Geoscience) He has more than 50 years of experience in groundwater hydrology and has directed more than 2,000 hydrogeologic investigations and groundwater models and overseen design and construction for more than 1,000 groundwater production and monitoring wells. Dennis has been a consultant to the United Nations and several foreign governments, is a research professor at the University of Southern California’s Civil and Environmental Engineering Department and has taught graduate level courses in hydrogeology and ground water modeling since 1980.
Johnson Yeh
Principal Modeler
Dr. Johnson Yeh is a principal and lead groundwater modeler at Geoscience. During his more than 27 years of career, he has been involved in the project management of the firm’s groundwater modeling efforts, including some of its most high-profile geohydrologic investigations, groundwater basin/water quality studies, and artificial recharge projects. Dr. Yeh also possesses a broad knowledge of GIS tools utilized in support of modeling work and oversees Geoscience’s GIS staff members.
Dr. Yeh spearheads the generation and quality control of technical documents and technical presentations to both clients and regulators, including leading training and workshops on the use of models to the USGS and USEPA.
Terry A. Watkins
Principal Geohydrologist
Terry Watkins, PG, CHG
Terry has more than 19 years of experience in a variety of groundwater projects, including geohydrologic investigations, groundwater quality studies, artificial recharge projects, site feasibility and test drilling programs, sea water desalination programs, in addition to water well design, construction management, and supervision. Terry has completed more than 350 well projects over the course of his career. He is currently a Senior Geohydrologist at Geoscience and manages our well construction group, overseeing project aspects ranging from site evaluation and selection, preliminary well design, development of technical specifications, final well design, aquifer pump test analysis, development of well rehabilitation programs, and providing construction management services. Terry has performed project management and well construction management and supervision on several multi-well projects throughout California including municipal water supply wells, ASR wells, injection wells, and monitoring wells.
Terry is an active member of the American Water Works Association (AWWA). He serves as an alternate member of the Well Standards Committee (Standard A-100) as well as the California-Nevada Section of the AWWA and is a frequent speaker on well related topics.
Leveraging new technology for continuous improvement
We have worked hard for more than 40 years to earn our reputation as an industry leader and go-to resource for accurate, effective groundwater modeling and management. Decades developing and leveraging innovative technologies, building on Dr. Dennis Williams’ pioneering work, Geoscience continues to push the boundaries of groundwater science and industry best practices.
Join a team that knows their stuff
WORK WITH US
Geoscience is growing. We’re looking for innovative people with a passion for groundwater and an unwavering focus on customer service and excellent results. We make it our business to solve some of the toughest water issues and clients depend on us for successful outcomes and peace of mind.