David W Clow
Biography
Science and Products
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...
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,...
Snowpack 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...
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 Swiftwater Creek, MT long-term measurements of streamflow and water quality in areas of the United States that are minimally affected by human activities. Historically, the HBN has used a fixed-interval sampling strategy, however other more robust sampling strategies are now available. Trend networks, for example, can...
Linking 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...
Clow, David W.; Mast, M. Alisa; Sickman, James O. Influence 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...
Foks, Sydney; Stets, Edward G.; Singha, Kamini; Clow, David W. Snow 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...
Sexstone, Graham A.; Clow, David W.; Fassnacht, Steven R.; Liston, Glen E.; Hiemstra, Christopher A.; Knowles, John F.; Penn, Colin A. Organic 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-...
Mendonça, Raquel; Müller, Roger A.; Clow, David W.; Verpoorter, Charles; Raymond, Peter; Tranvik, Lars; Sobek, Sebastian 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
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,...
Forrester, Harrison; Clow, David W.; Roche, James W.; Heyvaert, Alan C.; Battaglin, William A. Inland waters and their role in the carbon cycle of Alaska
The magnitude of Alaska (AK) inland waters carbon (C) fluxes is likely to change in the future due to amplified climate warming impacts on the hydrology and biogeochemical processes in high latitude regions. Although current estimates of major aquatic C fluxes represent an essential baseline against which future change can be compared, a...
Stackpoole, Sarah M.; Butman, David E.; Clow, David W.; Verdin, Kristine L.; Gaglioti, Benjamin V.; Genet, Hélène; Striegl, Robert G. Spatial and temporal patterns of dissolved organic matter quantity and quality in the Mississippi River Basin, 1997–2013
Recent studies have found insignificant or decreasing trends in time-series dissolved organic carbon (DOC) datasets, questioning the assumption that long-term DOC concentrations in surface waters are increasing in response to anthropogenic forcing, including climate change, land use, and atmospheric acid deposition. We used the weighted...
Stackpoole, Sarah M.; Stets, Edward G.; Clow, David W.; Burns, Douglas A.; Aiken, George R.; Aulenbach, Brent T.; Creed, Irena F.; Hirsch, Robert M.; Laudon, Hjalmar; Pellerin, Brian; Striegl, Robert G. Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry
Mountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest....
Clow, David W.; Williams, Mark W.; Schuster, Paul F. Comparison of methods for quantifying surface sublimation over seasonally snow-covered terrain
Snow sublimation can be an important component of the snow-cover mass balance, and there is considerable interest in quantifying the role of this process within the water and energy balance of snow-covered regions. In recent years, robust eddy covariance (EC) instrumentation has been used to quantify snow sublimation over snow-covered surfaces in...
Sexstone, Graham A.; Clow, David W.; Stannard, David I.; Fassnacht, Steven R. Numerical experiments to explain multiscale hydrological responses to mountain pine beetle tree mortality in a headwater watershed
The effects of mountain pine beetle (MPB)-induced tree mortality on a headwater hydrologic system were investigated using an integrated physical modeling framework with a high-resolution computational grid. Simulations of MPB-affected and unaffected conditions, each with identical atmospheric forcing for a normal water year, were compared at...
Penn, Colin A.; Bearup, Lindsay A.; Maxwell, Reed M.; Clow, David W. Aquatic carbon cycling in the conterminous United States and implications for terrestrial carbon accounting
Inland water ecosystems dynamically process, transport, and sequester carbon. However, the transport of carbon through aquatic environments has not been quantitatively integrated in the context of terrestrial ecosystems. Here, we present the first integrated assessment, to our knowledge, of freshwater carbon fluxes for the conterminous United...
Butman, David; Stackpoole, Sarah M.; Stets, Edward G.; McDonald, Cory P.; Clow, David W.; Striegl, Robert G. Water-quality response to a high-elevation wildfire in the Colorado Front Range
Water quality of the Big Thompson River in the Front Range of Colorado was studied for 2 years following a high-elevation wildfire that started in October 2012 and burned 15% of the watershed. A combination of fixed-interval sampling and continuous water-quality monitors was used to examine the timing and magnitude of water-quality changes...
Mast, M. Alisa; Murphy, Sheila F.; Clow, David W.; Penn, Colin A.; Sexstone, Graham A.