Dave is a Research Hydrologist with the USGS Colorado Water Science Center in Lakewood, CO.
David Clow is a research hydrologist with the USGS in Denver, Colorado, where he began his career with the USGS in 1990. He received a PhD in geochemistry from the University of Wyoming in 1992. David’s research interests focus on effects of natural processes and anthropogenic disturbance on water resources in mountain environments.
Professional Experience
1990-present: Research Hydrologist in the Colorado Water Science Center, U.S.Geological Survey
Education and Certifications
B.S. Geology, 1983, California State University, Fresno
M.S. Geology, 1987, California State University, Fresno
Ph.D. Geochemistry, 1992, University of Wyoming
Science and Products
Linking water, carbon, and nitrogen cycles in seasonally snow-covered catchments under changing land resource conditions
Developing Tools for Improved Water Supply Forecasting in the Rio Grande Headwaters
Transport of dissolved organic matter by river networks from mountains to the sea: a re-examination of the role of flow across temporal and spatial scales
Snowpack Sublimation - Measurements and Modeling in the Colorado River Basin
Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed
Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States
Seasonal Atmospheric Nitrate and Ammonium Deposition along an Elevation Gradient in the Colorado Front Range using Ion Exchange Resin Columns (2018-2019)
Continuous water-quality data for selected streams in Rocky Mountain National Park, Colorado, water years 2011-19 (ver. 2.0, January 2022)
Continuous water-quality data for selected streams in Rocky Mountain National Park, Colorado, water years 2011-19
Wetland Stream Water Quality Data for West Twin Creek, AK, Allequash Creek, WI, and Big Thompson River, CO, 2010-2020
Climatological data for the Loch Vale watershed in Rocky Mountain National Park, Colorado, water years 1992-2019
A call for strategic water-quality monitoring to advance assessment and prediction of wildfire impacts on water supplies
Elevated nitrogen deposition to fire-prone forests adjacent to urban and agricultural areas, Colorado front range, USA
Spatiotemporal dynamics of CO2 gas exchange from headwater mountain streams
Mountain streams play an important role in the global carbon cycle by transporting, metabolizing, and exchanging carbon they receive from the terrestrial environment. The rates at which these processes occur remain highly uncertain because of a paucity of observations and the difficulty of measuring gas exchange rates in steep, turbulent mountain streams. This uncertainty is compounded by large te
Long-term ecosystem and biogeochemical research in Loch Vale watershed, Rocky Mountain National Park, Colorado
Spatial variability in seasonal snowpack trends across the Rio Grande headwaters (1984 - 2017)
Changes in climate and land cover affect seasonal streamflow forecasts in the Rio Grande headwaters
Preferential elution of ionic solutes in melting snowpacks: Improving process understanding through field observations and modeling in the Rocky Mountains
Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States
Influence of climate on alpine stream chemistry and water sources
Snow sublimation in mountain environments and its sensitivity to forest disturbance and climate warming
Organic carbon burial in global lakes and reservoirs
Effects of backpacker use, pack stock trail use, and pack stock grazing on water-quality indicators, including nutrients, E. coli, hormones, and pharmaceuticals, in Yosemite National Park, USA
Science and Products
- Science
Linking water, carbon, and nitrogen cycles in seasonally snow-covered catchments under changing land resource conditions
Changes in snowpack accumulation, distribution, and melt in high-elevation catchments are likely to have important impacts on water, carbon, and nitrogen cycles, which are tightly coupled through exchanges of energy and biogeochemical compounds between atmospheric, terrestrial, and aquatic environments. Our research helps to better understand how changes in climate will affect water availability...Developing Tools for Improved Water Supply Forecasting in the Rio Grande Headwaters
The Rio Grande River is a critical source of freshwater for 13 million people in Colorado, Texas, New Mexico, and Mexico. More than half of the Rio Grande’s streamflow originates as snowmelt in Colorado’s mountains, meaning that changes in the amount of snowmelt can impact the water supply for communities along the entire river. Snowmelt runoff is therefore an important component of water supply o...Transport of dissolved organic matter by river networks from mountains to the sea: a re-examination of the role of flow across temporal and spatial scales
The transport of dissolved organic matter (DOM) by rivers is an important component of the global carbon cycle, affects ecosystems and water quality, and reflects biogeochemical and hydrological processes in watersheds. Understanding the fundamental relationships between discharge and DOM concentration and composition reveals important information about watershed flow paths, soil flushing, connectSnowpack Sublimation - Measurements and Modeling in the Colorado River Basin
Snow is an essential resource in the western United States (U.S.), providing water for drinking, irrigation, industry, energy production, and ecosystems across much of the region. In the mountains of the western U.S., most precipitation falls as snow, which accumulates in seasonal snowpacks that serve as a large natural reservoir. Snowpack sublimation, which is analogous to evaporation from land...Water, Energy, and Biogeochemical Budgets (WEBB): Loch Vale Watershed
Loch Vale is an alpine/subalpine watershed in Rocky Mountain National Park where the U.S. Geological Survey has been conducting research since the 1980s. Our research has focused on the effects of climate change and atmospheric pollutants on water, soil, vegetation, and aquatic life. The alpine/subalpine ecosystem in Loch Vale is sensitive to changes in climate and air pollution. Our long-term...Water-Quality Sampling at Five Hydrologic Benchmark Stations in the Western United States
The Hydrologic Benchmark Network (HBN) was established in 1963 to provide long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities. - Data
Seasonal Atmospheric Nitrate and Ammonium Deposition along an Elevation Gradient in the Colorado Front Range using Ion Exchange Resin Columns (2018-2019)
Atmospheric deposition of reactive nitrogen (Nr) due to human activities can have measurable effects on ecosystem processing and export of nutrients, groundwater and surface-water quality. Rates of Nr deposition to lower-elevation forests immediately adjacent to the Denver/Boulder urban area, however, have only recently been measured. The focus of this study was to determine the extent of urban anContinuous water-quality data for selected streams in Rocky Mountain National Park, Colorado, water years 2011-19 (ver. 2.0, January 2022)
This data release contains water-quality and discharge data collected at seven stream sites and one groundwater spring in Rocky Mountain National Park (RMNP), Colorado by the U.S. Geological Survey (USGS) from 10/1/2010 to 9/30/2019 using in-situ sensors and field meters. Data were collected for the purpose of quantifying downstream transport of aquatic carbon and exchange fluxes of dissolved carbContinuous water-quality data for selected streams in Rocky Mountain National Park, Colorado, water years 2011-19
This data release contains water-quality and discharge data collected in Rocky Mountain National Park (RMNP), Colorado by the U.S. Geological Survey (USGS) from 10/1/2010 through 9/30/2019 using in-situ sensors and field meters. Data were collected for the purpose of quantifying exchange fluxes of dissolved carbon dioxide (CO₂) from streams. Parameters include daily mean dissolved CO₂, water tempeWetland Stream Water Quality Data for West Twin Creek, AK, Allequash Creek, WI, and Big Thompson River, CO, 2010-2020
This dataset includes discrete water quality and discharge data for three streams that flow through wetlands. There are two measurement and sampling locations on each stream: one immediately upstream from the wetland and one immediately downstream from the wetland. Measurements and sample collection occurred in 2010 and 2011 at West Twin Creek, AK; in 2019 and 2020 at Allequash Creek, WI; and in 2Climatological data for the Loch Vale watershed in Rocky Mountain National Park, Colorado, water years 1992-2019
This data release contains hourly means of climatological data collected by the U.S. Geological Survey (USGS) from 10/1/1991 to 9/30/2019 at three weather stations in the Loch Vale watershed in Rocky Mountain National Park (RMNP), Colorado. In order of increasing elevation, the three weather stations are Loch Vale meteorological station at RMNP, Colo. (Main weather station, USGS station 4017191053 - Publications
Filter Total Items: 66
A call for strategic water-quality monitoring to advance assessment and prediction of wildfire impacts on water supplies
Wildfires pose a risk to water supplies in the western U.S. and many other parts of the world, due to the potential for degradation of water quality. However, a lack of adequate data hinders prediction and assessment of post-wildfire impacts and recovery. The dearth of such data is related to lack of funding for monitoring extreme events and the challenge of measuring the outsized hydrologic and eAuthorsSheila F. Murphy, Charles N. Alpers, Chauncey W. Anderson, John R. Banta, Johanna Blake, Kurt D. Carpenter, Gregory D. Clark, David W. Clow, Laura A. Hempel, Deborah A. Martin, Michael Meador, Gregory Mendez, Anke Mueller-Solger, Marc A. Stewart, Sean E. Payne, Cara L. Peterman-Phipps, Brian A. EbelElevated nitrogen deposition to fire-prone forests adjacent to urban and agricultural areas, Colorado front range, USA
As humans increasingly dominate the nitrogen cycle, deposition of reactive nitrogen (Nr) will continue to have adverse consequences for ecosystems. In the Rocky Mountains, Nr deposition remains elevated and has become increasingly dominated by ammonium, despite efforts to reduce emissions. Currently, spatial models of Nr deposition do not fully account for urban and agricultural emissions, sourcesAuthorsRuth C. Heindel, Sheila F. Murphy, Deborah A. Repert, Gregory A. Wetherbee, Alexander Liethen, David W. Clow, Toby A. HalamkaSpatiotemporal dynamics of CO2 gas exchange from headwater mountain streams
Mountain streams play an important role in the global carbon cycle by transporting, metabolizing, and exchanging carbon they receive from the terrestrial environment. The rates at which these processes occur remain highly uncertain because of a paucity of observations and the difficulty of measuring gas exchange rates in steep, turbulent mountain streams. This uncertainty is compounded by large te
AuthorsDavid W. Clow, Robert G. Striegl, Mark DornblaserLong-term ecosystem and biogeochemical research in Loch Vale watershed, Rocky Mountain National Park, Colorado
Loch Vale watershed was instrumented in 1983 with initial support from the National Acid Precipitation Assessment Program to ask whether ecosystems of Rocky Mountain National Park (RMNP) were affected by acidic atmospheric deposition. Research and monitoring activities were expanded in 1991 by the U.S. Geological Survey Water, Energy, and Biogeochemical Budgets program to understand the processes,AuthorsJill S. Baron, David W. Clow, Isabella A. Oleksy, Timothy Weinmann, Caitlin Charlton, Amanda JayoSpatial variability in seasonal snowpack trends across the Rio Grande headwaters (1984 - 2017)
This study evaluated the spatial variability of trends in simulated snowpack properties across the Rio Grande headwaters of Colorado using the SnowModel snow evolution modeling system. SnowModel simulations were performed using a grid resolution of 100 m and 3-hourly time step over a 34-yr period (1984–2017). Atmospheric forcing was provided by phase 2 of the North American Land Data AssimilationAuthorsGraham A. Sexstone, Colin A. Penn, Glen Liston, Kelly Gleason, C. David Moeser, David W. ClowChanges in climate and land cover affect seasonal streamflow forecasts in the Rio Grande headwaters
Seasonal streamflow forecast bias, changes in climate, snowpack, and land cover, and the effects of these changes on relations between basin‐wide snowpack, SNOw TELemetry (SNOTEL) station snowpack, and seasonal streamflow were evaluated in the headwaters of the Rio Grande, Colorado. Results indicate that shifts in the seasonality of precipitation and changing climatology are consistent with periodAuthorsColin A. Penn, David W. Clow, Graham A. Sexstone, Sheila F. MurphyPreferential elution of ionic solutes in melting snowpacks: Improving process understanding through field observations and modeling in the Rocky Mountains
The preferential elution of ions from melting snowpacks is a complex problem that has been linked to temporary acidification of water bodies. However, the understanding of these processes in snowpacks around the world, including the polar regions that are experiencing unprecedented warming and melting, remains limited despite being instrumental in supporting climate change adaptation.In this studyAuthorsDiogo Costa, Graham A. Sexstone, J.W. Pomeroy, Donald H. Campbell, David W. Clow, Alisa MastLinking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States
Transit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in mountains oAuthorsDavid W. Clow, Alisa Mast, James O. SickmanInfluence of climate on alpine stream chemistry and water sources
The resilience of alpine/subalpine watersheds may be viewed as the resistance of streamflow or stream chemistry to change under varying climatic conditions, which is governed by the relative size (volume) and transit time of surface and subsurface water sources. Here, we use end‐member mixing analysis in Andrews Creek, an alpine stream in Rocky Mountain National Park, Colorado, from water year 199AuthorsSydney Foks, Edward G. Stets, Kamini Singha, David W. ClowSnow sublimation in mountain environments and its sensitivity to forest disturbance and climate warming
Snow sublimation is an important component of the snow mass balance, but the spatial and temporal variability of this process is not well understood in mountain environments. This study combines a process‐based snow model (SnowModel) with eddy covariance (EC) measurements to investigate (1) the spatio‐temporal variability of simulated snow sublimation with respect to station observations, (2) theAuthorsGraham A. Sexstone, David W. Clow, Steven R. Fassnacht, Glen E. Liston, Christopher A. Hiemstra, John F. Knowles, Colin A. PennOrganic carbon burial in global lakes and reservoirs
Burial in sediments removes organic carbon (OC) from the short-term biosphere-atmosphere carbon (C) cycle, and therefore prevents greenhouse gas production in natural systems. Although OC burial in lakes and reservoirs is faster than in the ocean, the magnitude of inland water OC burial is not well constrained. Here we generate the first global-scale and regionally resolved estimate of modern OC bAuthorsRaquel Mendonça, Roger A. Müller, David W. Clow, Charles Verpoorter, Peter Raymond, Lars Tranvik, Sebastian SobekEffects of backpacker use, pack stock trail use, and pack stock grazing on water-quality indicators, including nutrients, E. coli, hormones, and pharmaceuticals, in Yosemite National Park, USA
We investigated how visitor-use affects water quality in wilderness in Yosemite National Park. During the summers of 2012–2014, we collected and analyzed surface-water samples for water-quality indicators, including fecal indicator bacteria Escherichia coli, nutrients (nitrogen, phosphorus, carbon), suspended sediment concentration, pharmaceuticals, and hormones. Samples were collected upstream anAuthorsHarrison Forrester, David W. Clow, James W. Roche, Alan Heyvaert, William A. Battaglin - News