Rob is a Research Hydrologist with the Colorado Water Science Center
Professional Experience
1992-Present Research Hydrologist, U.S. Geological Survey, Denver, Colorado
1989-1992 Research Engineer, University of Colorado, Center for Advanced Decision Support in Water and Environmental Systems (CADSWES), Boulder, Colorado
1987-1989 Hydrologist, Minnesota Department of Natural Resources, Detroit Lakes, Minnesota
Education and Certifications
Bachelor of Science, Summa Cum Laude, 1985, Computer Science and Environmental Studies, Minnesota State University, Mankato
Master of Environmental Management, 1987, Water Resources, Duke University: Monte Carlo Analysis of the Surface Water Component for Land Disposal Restriction Determinations
Doctor of Philosophy, 1993, Environmental Engineering, University of Colorado: Development and Application of an Equilibrium-based Simulation Model for Reactive Solute Transport in Small Streams
Affiliations and Memberships*
Associate Editor, Water Resources Research, 2006–2014
Member, American Geophysical Union
Member, Society for Freshwater Science
Member, European Geosciences Union
Science and Products
Diel and synoptic sampling data from Boulder Creek and South Boulder Creek, near Boulder, Colorado, September–October 2019
Multiple sampling campaigns were conducted near Boulder, Colorado, to quantify constituent concentrations and loads in Boulder Creek and its tributary, South Boulder Creek. Diel sampling was initiated at approximately 1100 hours on September 17, 2019, and continued until approximately 2300 hours on September 18, 2019. During this time period, samples were collected at two locations on Boulder Cree
Discrete Metals and Ancillary Data Used in the Development of Surrogate Models for Estimating Metals Concentration in Surface Water of Three Hydrologic Basins (Delaware River, Illinois River and Upper Colorado River)
The release of metals (or metalloids) to surface water can involve both natural and anthropogenic sources. Elevated metals concentrations can pose a risk to human health, wildlife, and ecosystem health, with the modes of toxicity and extent of risk varying as a function of the specific metal, its chemical form and the matrix with which it is associated (for example, dissolved versus particulate).
Synoptic sampling data from upper Cement Creek near Gladstone, Colorado, October 2012, September 2019, and September 2020
Three synoptic sampling campaigns were conducted on upper Cement Creek, near Gladstone, Colorado, under low-flow conditions. The first campaign, conducted October 2012, was part of a larger campaign to characterize low-flow water quality in the entire Cement Creek watershed. The second campaign, conducted in September 2019, was designed to quantify metal loading and identify sources of contaminati
Geochemistry and Environmental Tracer Data for Groundwater, Stream Water, and Soil and Sediment from North Quartz Creek, Colorado
This U.S. Geological Survey (USGS) data release contains data from stream water, groundwater, and soil samples collected in 2019 and 2020 in the North Quartz Creek watershed in central Colorado. Fourteen streambank wells were installed in pairs at seven locations in August 2020 to capture the emerging groundwater from the left bank and right banks (relative to downstream-facing direction) and a sy
Stream discharge, sodium, bromide, and specific conductance data for stream and hyporheic zone samples affected by injection of sodium bromide tracer, Leavenworth Creek, Clear Creek County, Colorado, August 2012
Leavenworth Creek, a tributary of South Clear Creek and Clear Creek near Georgetown, Colorado contains copper, lead, and zinc concentrations that are near to or exceed aquatic life standards. The creek drains the Argentine mining district where mining was active primarily in the early 1900s. In the summer of 2012, the U.S. Geological Survey (USGS) conducted a metal-loading study using tracer dilut
Streamflow and water chemistry in the Tenaya Lake Basin, Yosemite National Park, California
The Tenaya Lake Water Budget Study seeks to quantify and understand the water balance within the principal snow accumulation and runoff yielding zone in the Sierra Nevada Mountains. The Study operates stage sensors and data loggers to record Tenaya Lake inflows, water surface elevation, and outflow, with continuous annual data collection for the 21 square-kilometer watershed located in the alpine
Water quality and discharge data from draining mine tunnels near Silverton, Colorado 1993-2015
The American Tunnel, the Black Hawk mine, the Gold King mine, the Mogul mine, and the Red and Bonita mine are located in the Cement Creek watershed, tributary to the upper Animas River near Silverton, Colorado. All five sites have tunnels that drain groundwater from abandoned underground mine workings to the surface. This draining water has elevated concentrations of metals and degrades water qual
Hydrologic reconnaissance to identify areas of emergent groundwater, Mineral Creek, near Silverton, Colorado, June 2020
Hydrologic reconnaissance of Mineral Creek near Silverton, Colo., was conducted from June 25-27, 2020. Both banks of Mineral Creek and the adjacent hillsides were walked, starting near the ghost town of Chattanooga and proceeding downstream to the confluence of Mineral Creek with the Middle Fork of Mineral Creek. The purpose of this reconnaissance was to identify areas of emergent groundwater on
Synoptic sampling data from Illinois Gulch and Iron Springs near Breckenridge, Colorado, August 2016 and September 2017
Two synoptic sampling campaigns were conducted near Breckenridge, Colorado, to quantify metal loading to Illinois Gulch, a tributary of the Blue River. The first campaign, conducted in August 2016, was designed to determine the degree to which Illinois Gulch loses water to the underlying mine workings, and to determine the effect of these losses on observed metal loads. The second campaign, conduc
Hydrologic, biogeochemical, and radon data collected within and adjacent to the Little Wind River near Riverton, Wyoming
The U.S. Geological Survey is studying the interaction of a contaminated groundwater plume enriched in uranium and other trace elements with water, sediment, and biota along a 3 km reach of the Little Wind River in central Wyoming. The source of the contaminants is from a reclaimed uranium mill site near Riverton, Wyoming. The study is being done in collaboration with the Department of Energy, Uni
Filter Total Items: 69
Interaction of a legacy groundwater contaminant plume with the Little Wind River from 2015 through 2017, Riverton Processing site, Wyoming
The Riverton Processing site was a uranium mill 4 kilometers southwest of Riverton, Wyoming, that prepared uranium ore for nuclear reactors and weapons from 1958 to 1963. The U.S. Department of Energy completed surface remediation of the uranium tailings in 1989; however, groundwater below and downgradient from the tailings site and nearby Little Wind River was not remediated. Beginning in 2010, a
Incorporating streambank wells in stream mass loading studies to more effectively identify sources of solutes in stream water
Stream synoptic sampling studies that include flow estimates derived from the stream tracer dilution method are now commonly performed to identify sources and processes controlling solute transport to streams. However, a limitation of this mass-loading approach is its inability to identify the side of the stream on which a source is located in the common case where loading is largely from groundwa
Numerical modelling of mine pollution to inform remediation decision-making in watersheds
Prioritisation of mine pollution sources for remediation is a key challenge facing environmental managers. This paper presents a numerical modelling methodology to evaluate potential improvements in stream water quality from remediation of important mine pollution sources. High spatial resolution synoptic sampling data from a Welsh watershed were used to calibrate the OTIS solute transport model.
Quantification of metal loading using tracer dilution and instantaneous synoptic sampling and importance of diel cycling in Leavenworth Creek, Clear Creek County, Colorado, 2012
Leavenworth Creek, a tributary of South Clear Creek and Clear Creek near Georgetown, Colorado, contains copper, lead, and zinc at concentrations close to or in excess of aquatic-life standards. In the summer of 2012, the U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service and the Colorado Division of Reclamation, Mining and Safety, conducted monitoring to
A simple low-cost approach for transport parameter determination in mountain rivers
A simplified low-cost approach to experimentally determine transport parameters in mountain rivers is described, with an emphasis on the longitudinal dispersion coefficient (DL). The approach is based on a slug injection of table salt (NaCl) as a tracer and specific conductance readings at different locations downstream of the injection spot. Observed specific conductance readings are fit using th
Effects of hydrologic variability and remedial actions on first flush and metal loading from streams draining the Silverton caldera, 1992–2014
This study examined water quality in the upper Animas River watershed, a mined watershed that gained notoriety following the 2015 Gold King mine release of acid mine drainage to downstream communities. Water-quality data were used to evaluate trends in metal concentrations and loads over a two-decade period. Selected sites included three sites on tributary streams and one main-stem site on the Ani
Assessment of a conservative mixing model for the evaluation of constituent behavior below river confluences, Elqui River Basin, Chile
Fate and transport modeling of water-borne contaminants is a data demanding and costly endeavor, requiring considerable expes such, it becomes important to know when a complex modeling approach is required, and when a simpler approach is adequate. This is the main objective herein, where a conservative mixing model is used to characterize the transport of As, Cu, Fe, and SO4. The study area is div
Water-quality change following remediation using structural bulkheads in abandoned draining mines, upper Arkansas River and upper Animas River, Colorado USA
Water-quality effects after remediating abandoned draining mine tunnels using structural bulkheads were examined in two study areas in Colorado, USA. A bulkhead was installed in the Dinero mine tunnel in 2009 to improve water quality in Lake Fork Creek, a tributary to the upper Arkansas River. Although bulkhead installation improved pH, and manganese and zinc concentrations and loads at the Dinero
Critical shifts in trace metal transport and remediation performance under future low river flows
Exceptionally low river flows are predicted to become more frequent and more severe across many global regions as a consequence of climate change. Investigations of trace metal transport dynamics across streamflows reveal stark changes in water chemistry, metal transformation processes, and remediation effectiveness under exceptionally low-flow conditions. High spatial resolution hydrological and
Transport and speciation of uranium in groundwater-surface water systems impacted by legacy milling operations
Growing worldwide concern over uranium contamination of groundwater resources has placed an emphasis on understanding uranium transport dynamics and potential toxicity in groundwater-surface water systems. In this study, we utilized novel in-situ sampling methods to establish the location and magnitude of contaminated groundwater entry into a receiving surface water environment, and to investigate
Exploring the potential of ground-penetrating radar (GPR) to measure the extent of chronic disturbance in peatlands: Examples from acid mine drainage and peat fire
Peatlands are accumulations of partially decayed organic soil that cover approximately 3% of Earth’s surface and have been shown to serve essential environmental and ecological functions such as sequestering carbon, purifying water, and providing habitat for organisms. However, peatlands are threatened by pressures from agriculture, urban development, mining, and climate change. Geophysical method
Cinnamon gulch revisited: Another look at separating natural and mining-impacted contributions to instream metal load
Baseline, premining data for streams draining abandoned mine lands is virtually non existent, and indirect methods for estimating premining conditions are needed to establish realistic, cost effective cleanup goals. One such indirect method is the proximal analog approach, in which premining conditions are estimated using data from nearby mineralized areas that are unaffected by mining. In this pa
One-Dimensional Transport with Equilibrium Chemistry (OTEQ): A Reactive Transport Model for Streams and Rivers
OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage.
One-Dimensional Transport with Inflow and Storage (OTIS): A Solute Transport Model for Streams and Rivers
OTIS is a mathematical simulation model used to characterize the fate and transport of water-borne solutes in streams and rivers.
The governing equation underlying the model is the advection-dispersion equation with additional terms to account for transient storage, lateral inflow, first-order decay, and sorption.
Science and Products
- Data
Diel and synoptic sampling data from Boulder Creek and South Boulder Creek, near Boulder, Colorado, September–October 2019
Multiple sampling campaigns were conducted near Boulder, Colorado, to quantify constituent concentrations and loads in Boulder Creek and its tributary, South Boulder Creek. Diel sampling was initiated at approximately 1100 hours on September 17, 2019, and continued until approximately 2300 hours on September 18, 2019. During this time period, samples were collected at two locations on Boulder CreeDiscrete Metals and Ancillary Data Used in the Development of Surrogate Models for Estimating Metals Concentration in Surface Water of Three Hydrologic Basins (Delaware River, Illinois River and Upper Colorado River)
The release of metals (or metalloids) to surface water can involve both natural and anthropogenic sources. Elevated metals concentrations can pose a risk to human health, wildlife, and ecosystem health, with the modes of toxicity and extent of risk varying as a function of the specific metal, its chemical form and the matrix with which it is associated (for example, dissolved versus particulate).Synoptic sampling data from upper Cement Creek near Gladstone, Colorado, October 2012, September 2019, and September 2020
Three synoptic sampling campaigns were conducted on upper Cement Creek, near Gladstone, Colorado, under low-flow conditions. The first campaign, conducted October 2012, was part of a larger campaign to characterize low-flow water quality in the entire Cement Creek watershed. The second campaign, conducted in September 2019, was designed to quantify metal loading and identify sources of contaminatiGeochemistry and Environmental Tracer Data for Groundwater, Stream Water, and Soil and Sediment from North Quartz Creek, Colorado
This U.S. Geological Survey (USGS) data release contains data from stream water, groundwater, and soil samples collected in 2019 and 2020 in the North Quartz Creek watershed in central Colorado. Fourteen streambank wells were installed in pairs at seven locations in August 2020 to capture the emerging groundwater from the left bank and right banks (relative to downstream-facing direction) and a syStream discharge, sodium, bromide, and specific conductance data for stream and hyporheic zone samples affected by injection of sodium bromide tracer, Leavenworth Creek, Clear Creek County, Colorado, August 2012
Leavenworth Creek, a tributary of South Clear Creek and Clear Creek near Georgetown, Colorado contains copper, lead, and zinc concentrations that are near to or exceed aquatic life standards. The creek drains the Argentine mining district where mining was active primarily in the early 1900s. In the summer of 2012, the U.S. Geological Survey (USGS) conducted a metal-loading study using tracer dilutStreamflow and water chemistry in the Tenaya Lake Basin, Yosemite National Park, California
The Tenaya Lake Water Budget Study seeks to quantify and understand the water balance within the principal snow accumulation and runoff yielding zone in the Sierra Nevada Mountains. The Study operates stage sensors and data loggers to record Tenaya Lake inflows, water surface elevation, and outflow, with continuous annual data collection for the 21 square-kilometer watershed located in the alpineWater quality and discharge data from draining mine tunnels near Silverton, Colorado 1993-2015
The American Tunnel, the Black Hawk mine, the Gold King mine, the Mogul mine, and the Red and Bonita mine are located in the Cement Creek watershed, tributary to the upper Animas River near Silverton, Colorado. All five sites have tunnels that drain groundwater from abandoned underground mine workings to the surface. This draining water has elevated concentrations of metals and degrades water qualHydrologic reconnaissance to identify areas of emergent groundwater, Mineral Creek, near Silverton, Colorado, June 2020
Hydrologic reconnaissance of Mineral Creek near Silverton, Colo., was conducted from June 25-27, 2020. Both banks of Mineral Creek and the adjacent hillsides were walked, starting near the ghost town of Chattanooga and proceeding downstream to the confluence of Mineral Creek with the Middle Fork of Mineral Creek. The purpose of this reconnaissance was to identify areas of emergent groundwater onSynoptic sampling data from Illinois Gulch and Iron Springs near Breckenridge, Colorado, August 2016 and September 2017
Two synoptic sampling campaigns were conducted near Breckenridge, Colorado, to quantify metal loading to Illinois Gulch, a tributary of the Blue River. The first campaign, conducted in August 2016, was designed to determine the degree to which Illinois Gulch loses water to the underlying mine workings, and to determine the effect of these losses on observed metal loads. The second campaign, conducHydrologic, biogeochemical, and radon data collected within and adjacent to the Little Wind River near Riverton, Wyoming
The U.S. Geological Survey is studying the interaction of a contaminated groundwater plume enriched in uranium and other trace elements with water, sediment, and biota along a 3 km reach of the Little Wind River in central Wyoming. The source of the contaminants is from a reclaimed uranium mill site near Riverton, Wyoming. The study is being done in collaboration with the Department of Energy, Uni - Multimedia
- Publications
Filter Total Items: 69
Interaction of a legacy groundwater contaminant plume with the Little Wind River from 2015 through 2017, Riverton Processing site, Wyoming
The Riverton Processing site was a uranium mill 4 kilometers southwest of Riverton, Wyoming, that prepared uranium ore for nuclear reactors and weapons from 1958 to 1963. The U.S. Department of Energy completed surface remediation of the uranium tailings in 1989; however, groundwater below and downgradient from the tailings site and nearby Little Wind River was not remediated. Beginning in 2010, aIncorporating streambank wells in stream mass loading studies to more effectively identify sources of solutes in stream water
Stream synoptic sampling studies that include flow estimates derived from the stream tracer dilution method are now commonly performed to identify sources and processes controlling solute transport to streams. However, a limitation of this mass-loading approach is its inability to identify the side of the stream on which a source is located in the common case where loading is largely from groundwaNumerical modelling of mine pollution to inform remediation decision-making in watersheds
Prioritisation of mine pollution sources for remediation is a key challenge facing environmental managers. This paper presents a numerical modelling methodology to evaluate potential improvements in stream water quality from remediation of important mine pollution sources. High spatial resolution synoptic sampling data from a Welsh watershed were used to calibrate the OTIS solute transport model.Quantification of metal loading using tracer dilution and instantaneous synoptic sampling and importance of diel cycling in Leavenworth Creek, Clear Creek County, Colorado, 2012
Leavenworth Creek, a tributary of South Clear Creek and Clear Creek near Georgetown, Colorado, contains copper, lead, and zinc at concentrations close to or in excess of aquatic-life standards. In the summer of 2012, the U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture Forest Service and the Colorado Division of Reclamation, Mining and Safety, conducted monitoring toA simple low-cost approach for transport parameter determination in mountain rivers
A simplified low-cost approach to experimentally determine transport parameters in mountain rivers is described, with an emphasis on the longitudinal dispersion coefficient (DL). The approach is based on a slug injection of table salt (NaCl) as a tracer and specific conductance readings at different locations downstream of the injection spot. Observed specific conductance readings are fit using thEffects of hydrologic variability and remedial actions on first flush and metal loading from streams draining the Silverton caldera, 1992–2014
This study examined water quality in the upper Animas River watershed, a mined watershed that gained notoriety following the 2015 Gold King mine release of acid mine drainage to downstream communities. Water-quality data were used to evaluate trends in metal concentrations and loads over a two-decade period. Selected sites included three sites on tributary streams and one main-stem site on the AniAssessment of a conservative mixing model for the evaluation of constituent behavior below river confluences, Elqui River Basin, Chile
Fate and transport modeling of water-borne contaminants is a data demanding and costly endeavor, requiring considerable expes such, it becomes important to know when a complex modeling approach is required, and when a simpler approach is adequate. This is the main objective herein, where a conservative mixing model is used to characterize the transport of As, Cu, Fe, and SO4. The study area is divWater-quality change following remediation using structural bulkheads in abandoned draining mines, upper Arkansas River and upper Animas River, Colorado USA
Water-quality effects after remediating abandoned draining mine tunnels using structural bulkheads were examined in two study areas in Colorado, USA. A bulkhead was installed in the Dinero mine tunnel in 2009 to improve water quality in Lake Fork Creek, a tributary to the upper Arkansas River. Although bulkhead installation improved pH, and manganese and zinc concentrations and loads at the DineroCritical shifts in trace metal transport and remediation performance under future low river flows
Exceptionally low river flows are predicted to become more frequent and more severe across many global regions as a consequence of climate change. Investigations of trace metal transport dynamics across streamflows reveal stark changes in water chemistry, metal transformation processes, and remediation effectiveness under exceptionally low-flow conditions. High spatial resolution hydrological andTransport and speciation of uranium in groundwater-surface water systems impacted by legacy milling operations
Growing worldwide concern over uranium contamination of groundwater resources has placed an emphasis on understanding uranium transport dynamics and potential toxicity in groundwater-surface water systems. In this study, we utilized novel in-situ sampling methods to establish the location and magnitude of contaminated groundwater entry into a receiving surface water environment, and to investigateExploring the potential of ground-penetrating radar (GPR) to measure the extent of chronic disturbance in peatlands: Examples from acid mine drainage and peat fire
Peatlands are accumulations of partially decayed organic soil that cover approximately 3% of Earth’s surface and have been shown to serve essential environmental and ecological functions such as sequestering carbon, purifying water, and providing habitat for organisms. However, peatlands are threatened by pressures from agriculture, urban development, mining, and climate change. Geophysical methodCinnamon gulch revisited: Another look at separating natural and mining-impacted contributions to instream metal load
Baseline, premining data for streams draining abandoned mine lands is virtually non existent, and indirect methods for estimating premining conditions are needed to establish realistic, cost effective cleanup goals. One such indirect method is the proximal analog approach, in which premining conditions are estimated using data from nearby mineralized areas that are unaffected by mining. In this pa - Software
One-Dimensional Transport with Equilibrium Chemistry (OTEQ): A Reactive Transport Model for Streams and Rivers
OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage.
One-Dimensional Transport with Inflow and Storage (OTIS): A Solute Transport Model for Streams and Rivers
OTIS is a mathematical simulation model used to characterize the fate and transport of water-borne solutes in streams and rivers.
The governing equation underlying the model is the advection-dispersion equation with additional terms to account for transient storage, lateral inflow, first-order decay, and sorption.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government