Hydrogeology Experience - Darrel Dunn, Ph.D., PG
Table of Contents
Colorado Springs, Colorado, USA
Wyoming Registered Professional Geology License PG-679.
Hydrogeology work experience includes:
Unaffiliated consulting hydrogeologist - geologist
Senior hydrogeologist for engineering and environmental firms
Senior hydrogeologist for a government water management and planning agency
University teaching and research in hydrogeology and geology at assistant and associate professor levels
Performed hydrogeologic work in the following states and countries:
Tanzania, East Africa.
To see geology (non-hydrologic) experience, press the button 🔳.
Red is states and provinces where I have worked. Dots are locations of offices where I have worked.
The following content shows types of hydrogeology work that I have done, with one or more examples for each type. The list not exhaustive and the examples are not all-inclusive.
Integrated Surface Water and Groundwater Modeling
Managed the development of an integrated surface water and groundwater model using the DHI (Danish Hydraulic Institute) Mike She and Mike 11 models and applied the integrated model to the operation of canal system control structures and municipal wellfields for water resource planning and management (Broward County, Florida).
Groundwater Modeling (Senior Groundwater Modeler)
Wrote computer code for a (finite-difference) model of a municipal wellfield with widely separated wells and calibrated it to wellfield data (Ph.D. Thesis).
Managed site-wide groundwater fate and transport modeling for the U.S. Department of Energy's Feed Material Production Center, Fernald, Ohio, using SWIFT III (Sandia Waste Isolation Flow Transport)
Performed quality assurance review of groundwater flow modeling (MODFLOW) for planning closure of a hazardous waste site (California).
Lead a peer review team in an evaluation of groundwater data and modeling used to support the DOE's Waste Isolation Pilot Plant (WIPP) Certificate of Compliance Application for radioactive nuclear waste disposal (New Mexico).
Performed groundwater flow modeling (MODFLOW/MODPATH) at Rocky Flats Plant, Golden, Colorado.
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.
Supervised groundwater flow modeling in areas of contamination plumes at Edwards Air Force Base, California (MODFLOW).
Used my own finite-difference model to estimate groundwater inflow to a proposed open-pit coal mine (Wyoming).
Managed the development of a county wellfield protection model using MODFLOW and innovative Fortran code for groundwater capture zones (Broward County, Florida).
Performed site-wide analytical solute transport modeling at Hanford Superfund Site, Washington.
Developed a MODFLOW model of groundwater flow in surficial sand and gravel and used MODPATH for particle tracking.
Taught graduate level course titled "Groundwater Modeling" at the University of Toledo, Ohio.
Performed comprehensive studies of representative mountain watershed hydrologic systems to support development of a watershed computer model (Montana).
Published paper titled "An Experiment in Deterministic Watershed Modeling": Water Resources Bulletin, 7.
Published paper titled "Hydrosim - Computerized Graphical Stream Hydrograph Simulation": report No. 22, Montana Joint Water Resources Research Center.
Taught graduate level course titled "Watershed Hydrology" at the University of Toledo, Ohio.
Water Well Testing
Tested an irrigation well at 1600 gpm, to estimate the potential yield of the well (Montana).
Tested groundwater exploration wells at Montana State Prison. Used step test procedures with inflatable packers to isolate aquifers.
Provided senior technical guidance and review for performing and analyzing pumping tests and tracer tests at a U.S. Department of Energy nuclear facility, Rocky Flats Plant, Golden, Colorado.
Pump tested surficial aquifer for residential subdivision central water supply (Missioula, Montana).
Pump tested new municipal water supply well to estimate effect of improper well construction (Montana.
Pump tested a water supply well in a fractured aquifer at a hospital. Used downhole flow meter to determine productive zones (Helena, Montana).
Step tested an industrial water supply well to determine well loss as part of a well rehabilitation project (Missoula, Montana).
Analyzed aquifer step test data for wells on Zanzibar, Tanzania, East Africa.
Developed additional groundwater supply for Montana State Prison. Performed geologic investigation to select locations for test wells, supervised construction and testing using inflatable packers to isolate intervals, chose site for production well, wrote specifications for a large diameter production well using reverse rotary drilling, tested the well and selected pump size that would provide the needed water without pumping sand and silt or clogging. Others had failed to find and develop an additional groundwater supply at the Prison.
Performed numerous groundwater supply investigations for proposed real estate subdivisions, including water well drawdown calculations for safe yield and sustainability (Montana).
Wrote "Water Resources Report" for a Colorado Subdivision.
Performed a groundwater resource assessment for a Ranch in New Mexico.
Published paper titled "Groundwater Quality - An Overview, Broward County, Florida": Broward County Department of Planning and Environmental Protection Technical Report 01-07.
Performed a study of effects of agriculture and urbanization on groundwater levels and groundwater quality, Gallatin Valley, Montana.
Constructed monitoring wells and supervised collection and analysis of groundwater samples. Results were published.
Sampled domestic water wells in the vicinity of an oil well drilling site for groundwater contamination while the well was being drilled and reported the results (Gallatin County, Montana).
Designed a groundwater monitoring well system for a gold mine tailings site, step-tested the wells, and wrote a groundwater sampling protocol (Monana).
Supervised monitoring well construction staff at the Rocky Flats Superfund Site, Colorado.
Aquifer Safe Yield - Aquifer Depletion (Sustainability)
Supervised computer modeling to estimate safe yield of the Biscayne Aquifer in Broward County, Florida, without producing undesired effects on saltwater intrusion, wetlands, and Everglades Restoration.
Simulated aquifer depletion by proposed rural subdivisions (Montana).
Water Resources Management
Wrote the statement of work for development of the Integrated Water Resources Management Master Plan for Broward County, Florida. This was a $1 million contract involving a 25-year plan based on integrated surface water and groundwater modeling.
Utilized and integrated surface water and groundwater model to examine alternative operation of canal control structures to provide groundwater recharge to benefit municipal wellfields and reduce coastal saltwater intrusion in Broward County, Florida.
Water Resources Planning
Performed groundwater quality sampling and assessment to support areawide water resources planning for Gallatin County, Montana.
Supervised the Groundwater and Surface Water Planning Section, Water Resources Division, Department of Environmental Protection, Broward County, Florida, for 11 years.
Performed a three-dimensional mapping study of the historical progress of saltwater intrusion near a large municipal wellfield in Florida. To see the report on this study press here.
Managed coastal saltwater intrusion monitoring and analysis for Broward County, Florida.
Managed saltwater intrusion modeling with SEAWAT (Broward County, Florida).
Water Well Rehabilitation
Designed rehabilitation method for a well at a paper mill that was clogged by microbial deposits, using acid and surging (Missoula, Montana).
Groundwater Quality and Contamination Modeling
Lead a group of modelers simulating a uranium plume in groundwater at a U.S. Department of Energy uranium processing plant using SWIFT III (Fernald, Ohio).
Developed a model of groundwater contaminant transport (tetrachloroethylene, TCE) at Fort Chaffee, Arkansas (Modflow and MT3D).
Performed site-wide groundwater contaminant transport modeling at U.S. Department of Energy's Hanford Site, Richland, Washington. (Chromium, uranium, etc.)
Wrote computer program for calculating cleanup duration of contaminated groundwater plumes at the Hanford Site.
Performed groundwater contaminant transport modeling at the Idaho National Engineering Laboratory.
Surface Water Modeling
Simulated water management alternatives for operating control structures and pumps in the canal system of Broward County, Florida, using an integrated surface water and groundwater model (Mike 11/Mike She).
Surface Water Quality and Contamination Modeling
Calibrated a surface water quality model (EcoLab) to quarterly water quality measurements downstream from a water treatment plant (Broward County, Florida).
Groundwater Quality Monitoring
Developed a groundwater monitoring plan for the tailings site of a large underground gold mining operation in Montana. Designed monitoring wells. Supervised monitoring well construction. Performed pumping tests on monitoring wells. Designed the monitoring plan. Potential contamination included chromium and arsenic.
Monitored water quality and quantity at water wells and springs near a petroleum exploration well in a populated mountain valley while the well was being drilled (Gallatin County, Montana).
Installed a system of monitoring wells in a large proposed industrial subdivision and supervised groundwater quality and water level monitoring (Toledo, Ohio).
Surface Water Quality Monitoring
Selected water quality monitoring sites downstream from a placer gold mine (Montana).
Supervised computer modeling for design of a pump and treat groundwater remediation system for a dissolved uranium plume (Fernald, Ohio).
Provided technical support for the design of a soil vapor extraction system at the Puerto Rico Air National Guard base..
Investigated the effect of applying nitrogen fertilizer via irrigation sprinkler water on groundwater quality (Montana).
Surface Water Depletion
Wrote computer code for depletion of streams by pumping wells.
Managed the development of the Broward County, Florida, wellfield protection model (Modflow), which involved simulating groundwater capture zones.
Artificial Groundwater Recharge
Investigated feasibility of artificial groundwater recharge using reclaimed wastewater (Boward County, Florida).
Aquifer Storage and Recovery
Completed short course on aquifer storage and recovery (ASR).
Reviewed reports on ASR well construction and testing (Florida).
Geothermal Resource Investigation
Investigated water temperature and flow rates at hot springs in Montana.
Geothermal Well Design
Assessed flood risk for proposed real estate subdivisions (Montana).
Managed computer modeling of effects of surface water management on flood risk (Broward County, Florida).
Flood Plain Mapping
Simulated the 100-year flood level (HEC-2) for a real estate subdivision on the Yellowstone River, Montana.
Streamflow Frequency Analysis
Developed flow duration curves and correlated low-flow frequency with watershed geology (Montana).
Contaminated Soil Mapping
Mapped soil contamination at a uranium processing site and developed a method for extrapolating contamination to depth to calculate volume of contaminated soil (Ohio).
Soil Moisture Modeling
Wrote computer code (finite-difference) for soil moisture seepage and movement.
Soil Moisture Monitoring
Installed soil moisture monitoring sensors and collected data for watershed analysis and modeling (Ohio).
Climatological Data Measurement
Set up climatological measurement system to get data for estimating evaporation and transpiration (Ohio).
Investigated tilted oil-water contacts in oil fields in Illinois to determine the cause.
Methane in Groundwater
Created web page on subsurface methane in the western United States. Click here.
GIS in Hydrology
Managed the development of GIS applications for water resource management in Broward County, Florida.
Real Estate Subdivision Investigations
Performed numerous environmental and water supply investigations required for permitting rural subdivisions in Montana, including suitability of septic system sites, flood hazard, slope stability, groundwater availability.
Used integrated Mike 11/Mike She surface and groundwater model to test management options for stormwater routing to enhance water wellfield recharge while controlling flood hazard and reducing coastal saltwater intrusion in northern Broward County, Florida.
Nuclear Waste Disposal
Lead an independent peer review team in an evaluation of groundwater data and modeling used to support the DOE's Waste Isolation Pilot Plant (WIPP) Certificate of Compliance Application for radioactive waste disposal near Carlsbad, New Mexico.
Fractured Aquifer Exploitation
Wrote specifications for a successful commercial water well in fractured rock (Montana).
Provided information on well completion and testing in a fractured bedrock aquifer (Montana).
Hydrogeology of the Stettler Area, Alberta for the Groundwater Division, Alberta Research Council, Edmonton.
Performed step test analysis for wells in Zanzibar, Tanzania, East Africa.
Expert Witness - Hydrogeology:
Investigated a claim that oil field enhanced recovery operations contaminated a drinking water well. Claim was settled to client's satisfaction (Wyoming).
Investigated contamination of water wells by Escherichia coli (Montana).
Water well construction
Investigated a claim that improper construction of municipal water well resulted in reduced yield of water, and testified in court. Used borehole imaging. (Montana)
Water logging of land
Investigated a claim that irrigation ditch maintenance practices were causing waterlogging of land due to water table mounding, and was deposed (Montana).
Investigated the potential drawdown effects of operating an irrigation well on nearby irrigation wells and testified in court (Montana).
Investigated the potential depletion effect of operating an irrigation well on a nearby stream and testified at a water rights hearing (Montana).
Investigated the potential effects of operating a geothermal well, and testified at a water rights hearing (Montana).
Investigated the effects of upstream irrigation on senior downstream water rights (Montana).
Investigated whether upslope irrigation caused land slumping that endangered a motel, and testified in court (Montana).
Analysed the stability of slopes in numerous real estate subdivisions in Montana.
Investigated potential hydrologic effects of draining a subsurface gold mine (Montana).
Investigated basement flooding near irrigation ditches (Montana).
University Teaching - Hydrogeology
University of Toledo, Toledo, Ohio (Graduate level courses)
Montana State University, Bozeman, Montana