HydroGeoLogica, Inc. was formed by Anita Johnson in Golden, Colorado in 2006, to provide consulting services in the hydrogeologic sciences. In 2010, Pam Rohal joined HydroGeoLogica, bringing expertise in geochemistry including geochemical characterization and water quality modeling for mining applications. Brent Johnson joined the HydroGeoLogica team in 2015, bringing his extensive experience in aqueous geochemistry and his innovative approaches to managing water quality issues.  Erik Guldbech, who joined in mid-2017, brings further geochemistry and hydrogeology expertise and has background in GIS analyses. Mary Ellen Wickham, and Jake Waples joined HydroGeoLogica in 2018. Like Brent, Jake brings many years of experience in aqueous geochemistry to the team. Mary Ellen brings a diverse skillset, assisting in both business operations and geosciences.

In addition to our core experts, HydroGeoLogica maintains a network of specialized, associate experts so we can build a focused team to address your mine water and waste issues.

anita johnson

Anita Johnson is a hydrogeologist with 25 years of professional experience in environmental consulting and mine water management. She is the owner of HydroGeoLogica, Inc, and has worked in Europe, North America, Central and South America, and Asia. 

Anita develops site-specific water balances for industrial, environmental, and mining applications using either visual dynamic systems (GoldSim) or spreadsheets.  She is experienced in the design and implementation of surface water and groundwater investigations and development of water management systems for a variety of sites, primarily mine related. She has extensive experience in aquifer testing design, implementation and analysis, and provides peer review on these subjects.  View Resume

brent johnson


Brent Johnson has 23 years of professional experience in hydrology, geochemistry, water quality prediction and management. He conducts hydrologic and geochemical studies for all phases of projects including feasibility, permitting, baseline studies, water use optimization, reclamation, and source control.  

Brent is familiar with Equator Principals, the International Cyanide Code, and ICMM’s water guidelines.  He has expertise in hydrogeologic characterization, saturated and unsaturated groundwater flow modeling, seepage modeling for dams and cover/liner systems and he has extensive experience in aqueous geo-chemistry, ARD and metals chemistry, and developing innovative approaches to managing water quality issues.  

Mr. Johnson has worked extensively at sites around the world including Asia, Africa, North and South America, and Europe, from tropical to northern latitude conditions, and he is fluent in English and Spanish. View Resume

pam rohal


Pamela Rohal is a geochemist with 18 years of experience providing geochemical and hydrogeological technical support, primarily to the mining and environmental industry.

Much of Pam's early project work dealt with mine site remediation projects focused on characterization and treatment of acid rock drainage impacts.

Over the last seven years, her focus has been on geochemical characterization/modeling and evaluating water quality impacts in support of mine permitting and operations; specifically, mine waste geochemical characterization, geochemical modeling of pit lake water quality and mine facility water quality seepage analyses.

In the United States, she has completed projects in Alaska, Arizona, Colorado, Idaho, Michigan, Montana, Nevada, and Wyoming and she has also worked on international projects in Chile, DRC (Africa), Guatemala, Honduras, Indonesia, and Australia.  View Resume

erik guldbech

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Erik Guldbech graduated from Colorado School of Mines in May of 2017 with his Master’s degree in Environmental Geochemistry. Erik received his Bachelor’s degree from Rutgers in Geological Sciences and a graduate certificate from Penn State in Geographic Information Systems. His experience includes geochemical reaction modeling with Geochemist’s Workbench and PhreeqC, unsaturated and saturated groundwater flow modeling, geographic spatial analysis, and cartography. He is familiar with mine site water balances, seepage modeling for dams, cover/liner modeling, and surface water hydrology.

Erik has completed projects in Nevada, Utah and Arizona. His field experience includes water quality testing, well testing, geological mapping, and core logging. He is currently working towards PG and PE certification.

Prior to entering the environmental consulting industry, Erik received a Bachelor’s of Fine Art in 3D animation and worked on film and television sets as a lighting technician. View Resume

mary ellen wickham

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Mary Ellen Wickham is a geoscientist with 17 years of experience in water resources planning, conservation, and hydrogeology.  Her career began in the desert southwest, preserving groundwater resources while developing conservation programs and water policy, and working in regulatory compliance.    Additionally, Mary Ellen has worked on various environmental investigations for water and energy projects, including hydrogeologic characterization, carbon sequestration, coal, and geothermal.  She has been an integral team member in both the public and private sectors providing extensive administrative and technical support. View Resume



Jacob Waples is a geochemist with over 17 years of professional experience in geochemical investigations, permitting, and closure evaluations for the mining industry.  Jacob has specialized in geochemical modeling using PHREEQC and The Geochemist’s Workbench for water quality predictions associated with permitting, closure planning, and treatment evaluations.  In his work, he has provided support to a range of projects, including multidisciplinary hydrogeochemical projects, support for engineering design projects, and geochemical investigations for mine remediation.

Jacob’s experience has included geochemical characterization and prediction for acid rock drainage, geochemical fingerprinting for source evaluation and hydrogeological evaluations, geochemical modeling for water quality predictions, and geochemical evaluations for waste management strategies.  His current work focuses on closure analyses for tailings storage facilities and waste rock facilities, as well as geochemical and water management issues for closure planning.

Jacob has worked on geochemical and hydrogeological evaluations for copper, gold, molybdenum, iron, coal, oil shale, platinum, and rare earth mines throughout the world, including Chile, Peru, Argentina, Mexico, Australia, Indonesia, and throughout the United States.  Jacob is fluent in English and proficient in Spanish. View Resume