CLEATH-HARRIS GEOLOGISTS, INC
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Our Geologists

"Our clients know who we are, know that we will be there when they need us, and know we will get the job done right."

Timothy S. Cleath, Vice President, PG, CHG, CEG

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Tim Cleath, a certified hydrogeologist (CHG) and certified engineering geologist (CEG) in California, is the founder and vice president of Cleath-Harris Geologists.  Tim has an extensive understanding of water resources gained through over 35 years of hands-on experience and personal involvement with water issues on the Central Coast.  Tim also performs volunteer work in hydrogeology that spans the globe.  Tim's knowledge of local ground water conditions and his working relationships with local and State agencies will greatly facilitate and expedite projects

Spencer J. Harris, President, PG, CHG, CEG

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Spencer Harris, a certified hydrogeologist (CHG) and certified engineering geologist (CEG) in California, is the president of Cleath-Harris Geologists.   Spencer has managed water resource projects for over 25 years,  following 10 years of prior experience in geophysical exploration and environmental consulting.  Spencer's varied background includes groundwater basin characterization and management, groundwater modeling, land surveying, environmental assessments, and experience in numerous field techniques related to subsurface investigations.  Spencer is a quality-oriented, creative professional with the hydrogeologic experience and understanding necessary to assess difficult issues, such as long-term sustainable yield and seawater intrusion.


Neil D. Currie, PG, CHG

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Senior Hydrogeologist Neil Currie received his Bachelor of Science in Earth Science in 2014 and his Master of Science in Petroleum and Natural Gas Engineering in 2017.  Neil's capabilities include borehole logging, geologic mapping, well design and construction monitoring, stream flow measurement and classification, groundwater monitoring, thermal modeling, reservoir modeling, geothermal ​characterization, mine reentry and evaluation, fracture characterization and modeling, carbon sequestration evaluation, resistivity studies, and various engineering design, evaluation, testing, and management techniques for petroleum and natural gas reservoirs.

Andrea M. Berge, PG

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Project Geologist Andrea Berge graduated with a Bachelor of Science degree in Geology in 2007, working in oil and gas fields as a senior mudlogger for eight years before joining Cleath-Harris Geologists in 2015.  Andrea’s capabilities include geologic mapping and cross-section preparations, well siting, well design and technical specifications, aquifer testing and interpretation, water quality sampling and interpretation, borehole logging, water level contour maps, hydrologic inventories, and water demand estimates.  Her responsibilities include project design, implementation, and reporting, client communication, regulatory compliance, budget control, scheduling, staff assignments, and contractor oversite and inspection.
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Timothy D. Kershaw

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Tim Kershaw received a Bachelor of Science in Environmental Engineering in 2010, and a Masters in Geography in 2013.   He joined Cleath-Harris Geologists as a GIS Specialist and Environmental Scientist in 2016.  Tim’s capabilities include GIS, groundwater modeling, surface water and groundwater monitoring, air quality monitoring, and laboratory analytical techniques.  Tim manages groundwater monitoring projects, providing program design, data analysis and interpretation, regulatory compliance, budget control, and client communications.

Gracie E. Doolin, GIT

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​Staff Geologist Gracie Doolin received her Masters of Science in Environmental Sciences and Management in 2023.  Her field capabilities include borehole logging, geologic mapping, resistivity and passive seismic geophysical surveys,  stream flow measurements, and groundwater monitoring.  Gracie is proficient in GIS and data analysis,  and provides support for a wide range of technical studies and reporting.


Addison E. Burke

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​Staff Geologist  Addison Burke received a Bachelor of Science in Environmental Earth and Soil Science with a concentration in Geology in 2024.  Addison's field  capabilities include resistivity and passive seismic geophysical surveys, geologic mapping, groundwater monitoring, and stream flow measurements.   She is proficient in GIS and the application of geophysical techniques and data processing to assist in the interpretation of subsurface geologic structure.

Jim M. Raney, PG

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​​Project Geologist Jim Raney received his Bachelor of Science in Earth Science in 2013 with a concentration in Land and Water Resources and completed a Master’s in Environmental Sciences and Management in 2024.  Jim has nine years of experience in environmental services, including groundwater monitoring and sampling, well drilling oversight, permit compliance, and borehole logging.  Jim is also proficient in GIS, hydrologic data analysis, geologic mapping, cross-section development, and client communication. 

75 Zaca Lane, Suite 110
San Luis Obispo, California 93401
(805) 543-1413 • [email protected]                                                                                                                                                                                                         
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