Darrel Dunn, Ph.D., PG


Colorado Springs, Colorado, USA

Email: ddunn@DunnHydroGeo.com


Extensive experience in hydrogeology, geology, and computer applications.  Experience also includes environmental geology and petroleum geology.   To see a list of types of hydrogeologic work that I have performed, with examples of projects completed, see my hydrogeology experience webpage.  To see a list of types of geologic work that I have performed, with examples of projects, see my geology experience webpage.

Worked as an employee of engineering firms, government agencies, universities, a petroleum company, and as an independent consultant to engineering firms, law firms (expert witness), mining companies, petroleum companies, manufacturing companies land developers, geothermal developers, government agencies, agricultural entities, and other types of clients.  Taught university courses in hydrogeology and geology at undergraduate and graduate levels at Montana State University and the University of Toledo, Ohio.  Completed hydrologic and geologic projects located coast to coast in the United States, plus Canada and Africa.


2008 - present:  Unaffiliated Senior Hydrogeologist and Geologist, Colorado Springs, CO.

Performed aquifer pumping test analyses for an engineering firm (East Africa).

Performed peer review of a water resources management plan based on an integrated surface water and groundwater computer model (Florida).

Performed a water resources investigation for a land owner. (New Mexico).

Consulted regarding water well testing, water well construction, injection well testing, groundwater exploration, springs, slope stability, streamflow analysis.

Developed the hydrogeologic and geologic web pages shown in the sidebar.

Provided information and answered questions related to topics in these web pages to correspondents in Colorado, North Dakota, Montana, Oregon, Pennsylvania, Canada, India, Australia, Germany and United Arab Emirates.

11 Years:  Supervisor, Groundwater and Surface Water Planning Section, Water Resources Division, Department of Environmental Protection, Broward County, Florida.

Managed the development of an integrated groundwater and surface water model of the hydrologic system in Broward County.  Applied the model to the operation of canal system control structures and municipal water wellfields for water resources planning and management, including municipal water supply, artificial groundwater recharge, saltwater intrusion (salinization), flood hazard, wetlands protection, and surface water and groundwater depletion.

Analyzed aquifer recharge possibilities.

Managed the development of a county wellfield protection groundwater model (MODFLOW).

Managed monitoring and analysis of saltwater intrusion into the karstic Biscayne Aquifer along the Atlantic coast, especially regarding contamination threat to municipal water wellfields.  This work included managing a project for computer saltwater intrusion modeling.

Performed surface water quality modeling relative to pollution of surface water.

Managed the development of Geographic Information System (GIS) applications for water resource management.

Represented Broward County on committees and working groups involved in the Comprehensive Everglades Restoration Program, Florida water resource regulation and planning, FEMA flood mapping, EPA Underground Injection Control (UIC).

Published technical reports on groundwater quality and saltwater intrusion.

Responded to public inquiries on water issues, and presented water information at public meetings.

Concurrent Consulting

Developed a groundwater flow and contaminant transport model (MODFLOW/MT3D) of groundwater contamination by the solvent TCE (trichloroethylene) at Ft. Chaffee, Arkansas, for the U.S. Army Corps of Engineers.  Simulated movement of contaminant plume to surface water.

Reviewed documents related to a water well construction contract for a law firm.

2 Years:  Independent Consulting Hydrogeologist, Denver, Colorado.

Lead a peer review team in an evaluation of groundwater data, aquifer pumping test analysis, and groundwater modeling used by Sandia National Laboratory, Albuquerque, New Mexico, to support the U.S. Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP) Certificate of Compliance Application for radioactive nuclear waste disposal near Carlsbad, New Mexico.

6 Years:  Earth Sciences Manager, Principal Hydrogeologist, Advanced Sciences Inc., Denver, Colorado.

Managed the Earth Sciences Group located in offices throughout the United States involved in hydrogeologic and environmental services.

Managed groundwater investigations at Rocky Flats Plant, Golden, Colorado; and performed groundwater flow (MODFLOW) and contaminant transport modeling for this CERCLA Superfund site.

Developed the groundwater hydrology part of a Remedial Action Environmental Impact Assessment for the DOE's Hanford radioactive materials processing site, Richland, Washington, a CERCLA Superfund site.  This work included groundwater and river water radioactive nuclide modeling. 

Performed groundwater radioactive contaminant transport modeling for the Idaho National Engineering Laboratory High Level Radioactive Waste Tank Farm Replacement Environmental Impact Statement.

Supervised groundwater modeling (MODFLOW) at Edwards Air Force Base, California, a CERCLA Superfund site.

Provided senior review on groundwater quality monitoring and remediation tasks for various Federal Aviation Administration Sites in the western United States, primarily underground storage tanks.

Provided technical support for subsurface testing for the design of a soil vapor extraction system at the Puerto Rico Air National Guard base for remediation of groundwater pollution by jet fuel.

Performed senior review of numerous landfill regulatory compliance audits for the U.S. Bureau of Land Management.

2 Years:  Manager of Hydrogeologic Modeling, IT Corporation, Pittsburgh, Pennsylvania.

Managed corporate hydrogeologic modeling group.

Managed site-wide groundwater flow and contaminant transport modeling for dissolved uranium at the DOE's Feed Material Production Center, Fernald, Ohio, a CERCLA Superfund site.

Managed computer mapping of contaminated soil at an abandoned uranium processing plant, Apollo, Pennsylvania.

Performed quality assurance review of groundwater modeling for planning closure of a hazardous waste materials disposal site at Vine Hill, California.

Provided technical support for hydrogeologic work at Superfund sites in Pennsylvania and New Jersey.


After receiving a Bachelor's Degree from the University of Illinois and performing military service,  I worked as a petroleum geologist with a major oil company in Illinois and Colorado.  I worked on petroleum exploration and production in these states plus Wyoming, Utah, New Mexico, Nevada, and Nebraska.  I then returned to the University of Illinois for graduate study focusing on hydrogeology, engineering geology, petroleum geology, and petroleum reservoir engineering.  I completed a Ph.D. thesis on the hydrogeology of the Stettler Area, Alberta, Canada, which included groundwater modeling of a municipal water wellfield with a computer.  Temporary work during summer breaks included petroleum exploration in Saskatchewan and Alberta, and petroleum reservoir analysis in Illinois.

After receiving my Ph.D., I held teaching and research positions at Montana State University, Bozeman; and the University of Toledo, Ohio.  I taught undergraduate and graduate level courses in geology and hydrogeology.  Research included computer simulation of the hydrologic systems of mountain watersheds, computer simulation of the movement of water through soil, and studying the groundwater system at an industrial park where a groundwater drainage system was installed.

I left the university teaching profession and did extensive consulting in Montana in hydrogeology and geology.  I performed numerous investigations that included the following types:

Clients included law firms (expert witness), engineering firms, petroleum firms, mining companies, industrial firms, agriculture firms, state agencies, planning agencies, federal agencies, real estate developers, geothermal developers, and a university.  Gave numerous depositions and testified in court as expert witness.


University of Illinois, Champaign/Urbana.

BS with Honors in Geology.  Split minor in mathematics/biology.

Ph.D. in Geology.  Split minor in mathematics/petrology.  Thesis: "Hydrogeology of the Stettler Area, Alberta, Canada."  Course work stressed hydrogeology, engineering geology, petroleum geology, and petroleum reservoir engineering.


Registered Professional Geologist, Wyoming License Number PG-679.


Geological Society of America


Derrickman on oil well drilling rig.



Hiking, birding.

For more information or details, send an email.

(Revised May 11, 2023)