Surface water / groundwater interactions; hyporheic zone hydrology and biogeochemistry; carbon, nitrogen, and phosphorus cycling; flow above / through frozen ground; preferential flow and soil pipe formation and transport.
Professional Experience
2011 - Present Research Hydrologist, U.S. Geological Survey (USGS), Anchorage, AK
2006 - 2011 Student Hydrologist, Branch of Regional Research, USGS, Boulder, CO
2005 - 2006 Research Assistant, Institute of Alpine and Arctic Research, University of Colorado, Boulder
2003 - 2005 Research Assistant, Semi-Arid Hydrology and Riparian Areas, University of Arizona, Tucson, AZ
2002 - 2003 Hydrologist Intern, Branch of Regional Research, USGS, Lakewood, CO
2001 - 2002 Hydrologist Intern, MA-RI Water District, USGS, Northborough, MA
Education and Certifications
PhD 2010 University of Colorado, Boulder, CO Civil, Environmental, and Architectural Engineering
MS 2005 University of Arizona, Tucson, AZ Department of Hydrology
BA 2001 Wesleyan University, Middletown, CT Earth and Environmental Sciences
Affiliations and Memberships*
American Geophysical Union, Hydrology and Cryosphere Sections
American Water Resources Association - Alaska Chapter
Association of Polar Early Career Scientists
Science and Products
The Rusting of Arctic Rivers: Freshwater Ecosystems Respond to Rapidly Uptaking Metals
Q&A: Arctic Rivers Project
Groundwater Flow and Temperature Modeling to Predict Stream Temperatures in Beaver Creek, Kenai Peninsula, Alaska
Assessment of Critical Landscape Conditions and Potential Change in the Coastal Plain of the Arctic National Wildlife Refuge to Support Habitat Management Decision Making
Beavers Impacting Tundra Ecosystems (BITE)
Biogeochemistry of glaciers
Arctic Lake Food Webs
Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Wolverine Glacier Ecosystem Studies
Matanuska-Susitna Borough Wetland Modeling
Arctic Coastal Plain Studies
Arctic – Boreal Catchment Studies
Macroinvertebrates From Streams and Springs in the 1002 Region of the Arctic National Wildlife Refuge, Alaska, 2021
Frequency domain electromagnetic induction (FDEM) geophysical data collected near the Agashashok River in the Noatak National Preserve, AK
Water Level, Temperature, and Discharge in West Twin Creek, Alaska, 2010 to 2012
Stream and River Chemistry in Watersheds of Northwestern Alaska, 2015-2019
Stream Temperatures in the Noatak River and Kobuk River Basins, Northwest Alaska, 2017 - 2019
Wetland Stream Water Quality Data for West Twin Creek, AK, Allequash Creek, WI, and Big Thompson River, CO, 2010-2020
Geochemistry of Water Sources in the Wolverine Glacier Watershed, Alaska in 2016 and 2017
Continuous Records of Shallow Soil Temperature and Moisture in the Noatak River Basin, Alaska
Meteorological Data from Two Locations in the Agashashok River Watershed, Northwestern Alaska, 2015 to 2017
Water quality and gas fluxes of Interior Alaska (2014-2018)
Descriptions, Depth to Refusal, and Field-Saturated Hydraulic Conductivity of Soils on the Arctic Coastal Plain of Alaska, 2012-2016
Physical, Hydraulic, and Thermal Properties of Soils in the Noatak River Basin, Alaska, 2016
Comparing sediment microbial communities of Arctic beaver ponds to tundra lakes and streams
Increasing Alaskan river discharge during the cold season is driven by recent warming
In hot water? Patterns of macroinvertebrate abundance in Arctic thaw ponds and relationships with environmental variables
Evaluating hydrologic region assignment techniques for ungaged basins in Alaska, USA
How beavers are changing Arctic landscapes and Earth’s climate
Sensitivity of headwater streamflow to thawing permafrost and vegetation change in a warming Arctic
Heterogeneous patterns of aged organic carbon export driven by hydrologic flow paths, soil texture, fire, and thaw in discontinuous permafrost headwaters
Multi-year, spatially extensive, watershed-scale synoptic stream chemistry and water quality conditions for six permafrost-underlain Arctic watersheds
Seasonality of solute flux and water source chemistry in a coastal glacierized watershed undergoing rapid change: Wolverine Glacier watershed, Alaska
Storm-scale and seasonal dynamics of carbon export from a nested subarctic watershed underlain by permafrost
Arctic insect emergence timing and composition differs across thaw ponds of varying morphology
Nitrogen biogeochemistry in a boreal headwater stream network in interior Alaska
Arctic Rivers Project: Connecting Indigenous knowledge and western science to strengthen collective understanding of the changing Arctic
The Arctic Rivers Project will weave together Indigenous knowledges, monitoring, and the modeling of climate, rivers (flows, temperature, ice), and fish to improve understanding of how Arctic rivers, ice transportation corridors, fish, and communities might be impacted by and adapt to climate change.
Science and Products
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Filter Total Items: 17
The Rusting of Arctic Rivers: Freshwater Ecosystems Respond to Rapidly Uptaking Metals
The water quality of streams and rivers in the Arctic is sensitive to rapid climate change and altered disturbance regimes.Q&A: Arctic Rivers Project
Alaska is home to numerous cultural and linguistic Indigenous groups and the largest number of Federally Recognized Tribes in the United States. Indigenous Alaskans, often living in rural remote communities, are facing multiple impacts due to climate change. As infrastructure, landscapes, and subsistence resources continue to be impacted by warming temperatures, the safety, well-being, and...Groundwater Flow and Temperature Modeling to Predict Stream Temperatures in Beaver Creek, Kenai Peninsula, Alaska
Salmon are an important resource to the ecosystems, economy, and culture of the Kenai Peninsula, Alaska. However, salmon are under increasing stress due to warming water temperatures and decreasing stream flow. Groundwater is a major contributor to many streams that can help maintain fish habitat during low flows and contributes cooler water that regulates stream temperatures in the warm summer moAssessment of Critical Landscape Conditions and Potential Change in the Coastal Plain of the Arctic National Wildlife Refuge to Support Habitat Management Decision Making
Areas along the Arctic coast are changing the fastest among all of Earth’s habitats due to climate change. The Arctic coast is a fragile ecosystem that provides habitat for migratory birds, endangered species, and species critical for local subsistence living. In this area, permafrost is thawing rapidly, changing how much and when water reaches rivers, ponds, lakes, wetlands and groundwater. In ad...Beavers Impacting Tundra Ecosystems (BITE)
The range expansion of the North American beaver (Castor canadensis) has implications for water quality, aquatic ecosystems, and fisheries in Arctic streams.Biogeochemistry of glaciers
Significant change to the Arctic and sub-arctic water cycle is underway, impacting hydrologic and biogeochemical fluxes. In southcentral Alaska, glacier mass loss, changes to precipitation (including the rain/snow fraction), thawing ground ice, and vegetation encroachment will change both magnitude and timing of water and solute fluxes downstream. Although altered fluxes of limiting nutrients are...Arctic Lake Food Webs
From 2011 to 2013 we investigated freshwater food webs of Arctic Coastal Plain lakes in Alaska to improve our understanding how Arctic freshwater food webs may respond to landscape change the warmer, drier future.Hydro-Ecology of Arctic Thawing (HEAT): Ecology
Permafrost thaw is leading to a myriad of changes in physical and chemical conditions throughout the Arctic.Wolverine Glacier Ecosystem Studies
This project is an extension of the long-term Wolverine Glacier Benchmark Glacier project and is improving our understanding of solutes and nutrients in glacier basins, and how they fuel downstream ecosystems.Matanuska-Susitna Borough Wetland Modeling
This project aims to improve our understanding of the role of wetlands in controlling streamflow in southcentral Alaska using a groundwater – surface water flow model that can recreate the dynamic interactions between streams and wetlands.Arctic Coastal Plain Studies
The Arctic Coastal Plain (ACP) is a large region of low-lying, lake-rich land on the North Slope of Alaska. This region is underlain by thick ground ice, which is susceptible to erosion and thaw. These physical changes are likely to alter ecosystems by changing the availability of habitats and food resources upon which wildlife depends. Our studies on the ACP aim to understand the link between...Arctic – Boreal Catchment Studies
Catchment hydrology focuses on the movement of water and solutes from landscapes to waterbodies. Our research addresses questions such as: Where is the stream water coming from? How long did it take to get here? What solutes, nutrients, and/or contaminants did the water pick up along the way? Because streams and lakes gather water and solutes, we can learn about the entire watershed by studying... - Data
Filter Total Items: 21
Macroinvertebrates From Streams and Springs in the 1002 Region of the Arctic National Wildlife Refuge, Alaska, 2021
This dataset includes tables related to macroinvertebrate collections in streams and springs of the 1002 region of the Arctic National Wildlife Refuge in northeastern Alaska. Macroinvertebrates were collected using kicknets and driftnets in April and August with the goal of comparing populations to those sampled from the same water bodies by the USGS in the 1970s.Frequency domain electromagnetic induction (FDEM) geophysical data collected near the Agashashok River in the Noatak National Preserve, AK
Frequency domain electromagnetic induction (FDEM) data were collected in September 2016 near the Agashashok River and its tributaries, within the Noatak National Preserve near Kotzebue, AK to aid in local permafrost mapping. Data were collected with a GEM-2 instrument (1.6 m coil separation, Geophex, Ltd.); a broadband sensor that measures the bulk conductivity and magnetic susceptibility of the sWater Level, Temperature, and Discharge in West Twin Creek, Alaska, 2010 to 2012
This data set includes 15-minute interval data on stream temperature, stage, and discharge from an upstream and downstream gaging location on West Twin Creek, a first-order tributary to Nome Creek in the White Mountains of Alaska.Stream and River Chemistry in Watersheds of Northwestern Alaska, 2015-2019
These data include stream water chemistry from headwater streams to large rivers across three national parks in Arctic Alaska: Bering Land Bridge National Preserve, Kobuk Valley National Park, and Noatak National Preserve.Stream Temperatures in the Noatak River and Kobuk River Basins, Northwest Alaska, 2017 - 2019
This data set includes 15-minute interval data on stream temperature from low-order streams and main-stem rivers in the Noatak and Kobuk River valleys in Northwestern Alaska, collected during the summer months. The water temperatures were determined using a HOBO Water Temp Pro v2 (Onset Computer Corporation, Bourne, MA, USA)with ±0.2 degrees C accuracy. Sensors were place in several locations withWetland 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 2Geochemistry of Water Sources in the Wolverine Glacier Watershed, Alaska in 2016 and 2017
Glaciers are critical sources of water and solutes to downstream riverine and marine ecosystems. Samples were collected from surface streams, groundwater, rain, snow, and ice in the Wolverine Glacier basin and analyzed for a broad suite of geochemical constituents including common field parameters, major ions, stable isotopes of water, nutrients, metals, and dissolved organic carbon.Continuous Records of Shallow Soil Temperature and Moisture in the Noatak River Basin, Alaska
Soil moisture and temperature were measured at four shallow depths in multiple locations within tundra and forested landscapes of the Agashashok River basin. The measurements were made continuously beginning in 2015 until the most recent download in summer, 2019 or until the sensors or loggers failed.Meteorological Data from Two Locations in the Agashashok River Watershed, Northwestern Alaska, 2015 to 2017
Meteorological data was collected from two locations in the Agashashok River Watershed, one high in the drainage located on tundra (67.5440 N, -161.6828 E) and a second on a rocky knoll near the watershed mouth (67.2821 N, -162.5841 E). The data contain information on air temperatures, rainfall, barometric pressure, relative humidity, incoming and outgoing radiation, and wind speed and direction.Water quality and gas fluxes of Interior Alaska (2014-2018)
This product consists of multiple tabular datasets and associated metadata of water quality information related to rivers, streams, and lakes in the Yukon River watershed between 2014 and 2018. This data release is apart of the National Aeronautics and Space Administration (NASA) funded Arctic-Boreal Vulnerability Experiment (ABoVE) and is an assessment of water quality and greenhouse gas fluxes wDescriptions, Depth to Refusal, and Field-Saturated Hydraulic Conductivity of Soils on the Arctic Coastal Plain of Alaska, 2012-2016
This dataset includes soil data collected from various landscapes adjacent to thaw ponds on the North Slope of Alaska between 2012 and 2018. The landscapes include ice-rich polygonal ground found on basin uplands, as well as bluffs and lake edges. At each site a visual description of soil type and texture was performed, and a permafrost probe was used to determine a 'depth to refusal'. Given thatPhysical, Hydraulic, and Thermal Properties of Soils in the Noatak River Basin, Alaska, 2016
This dataset includes physical, hydraulic, and thermal properties of soils collected in two sub-watersheds in the Noatak River Basin in northwestern Alaska. Physical properties include dry bulk density and porosity. Hydraulic properties include field- and lab-based hydraulic conductivity, soil-water retention data, and parameters used in a common soil-water retention model (van Genuchten model). T - Multimedia
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Filter Total Items: 45
Comparing sediment microbial communities of Arctic beaver ponds to tundra lakes and streams
In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into Arctic tundra ecosystems. Beaver ponds in Arctic watersheds are known to alter stream biogeochemistry, which is likely coupled with changes in the activity and composition of microbial communities inhabiting beaver pond sediments. We investigated bacterial, archaeal, and fungal communitAuthorsKelly Shannon, Natasha R. Christman, Byron C. Crump, Michael P. Carey, Joshua C. Koch, Laura L. Lapham, Jonathan A. O'Donnell, Brett A. Poulin, Ken D. Tape, Jason A. Clark, Frederick S. ColwellIncreasing Alaskan river discharge during the cold season is driven by recent warming
Arctic hydrology is experiencing rapid changes including earlier snow melt, permafrost degradation, increasing active layer depth, and reduced river ice, all of which are expected to lead to changes in stream flow regimes. Recently, long-term (>60 years) climate reanalysis and river discharge observation data have become available. We utilized these data to assess long-term changes in discharge anAuthorsD Blaskey, Joshua C. Koch, M. Gooseff, A. C. Newman, Yang Cheng, Jonathan A. O'Donnell, K MusselmanIn hot water? Patterns of macroinvertebrate abundance in Arctic thaw ponds and relationships with environmental variables
Ongoing environmental change across the Arctic is affecting many freshwater ecosystems, including small thaw ponds that support macroinvertebrates, thus potentially affecting important forage for fish and bird species. To accurately predict how fish and wildlife that depend on these macroinvertebrates will be affected by ecosystem change at high latitudes, understanding proximate factors that inflAuthorsKirsty E. B. Gurney, Joshua C. Koch, Joel A. Schmutz, J. H. Schmidt, Mark S. WipfliEvaluating hydrologic region assignment techniques for ungaged basins in Alaska, USA
Building continental-scale hydrologic models in data-sparse regions requires an understanding of spatial variation in hydrologic processes. Extending these models to ungaged locations requires techniques to group ungaged locations with gaged ones to make process importance and model parameter transfer decisions to ungaged locations. This analysis (1) tested the utility of fundamental streamflow stAuthorsTheodore B. Barnhart, William H. Farmer, John C. Hammond, Graham A. Sexstone, Janet H. Curran, Joshua C. Koch, Jessica M. DriscollHow beavers are changing Arctic landscapes and Earth’s climate
Beavers build dams that change the way water moves between streams, lakes, and the land. In Alaska, beavers are moving north from the forests into the Arctic tundra. When beavers build dams in the Arctic, they cause frozen soil, called permafrost, to thaw. Scientists are studying how beavers and the thawing of permafrost are impacting streams and rivers in Alaska’s national parks. For example, perAuthorsJonathan A. O'Donnell, Michael P. Carey, Brett Poulin, Ken Tape, Joshua C. KochSensitivity of headwater streamflow to thawing permafrost and vegetation change in a warming Arctic
Climate change has the potential to impact headwater streams in the Arctic by thawing permafrost and subsequently altering hydrologic regimes and vegetation distribution, physiognomy and productivity. Permafrost thaw and increased subsurface flow have been inferred from the chemistry of large rivers, but there is limited empirical evidence of the impacts to headwater streams. Here we demonstrate hAuthorsJoshua C. Koch, Ylva Sjöberg, Jonathan A. O'Donnell, Michael P. Carey, Pamela Sullivan, A. TerskaiaHeterogeneous patterns of aged organic carbon export driven by hydrologic flow paths, soil texture, fire, and thaw in discontinuous permafrost headwaters
Climate change is thawing and potentially mobilizing vast quantities of organic carbon (OC) previously stored for millennia in permafrost soils of northern circumpolar landscapes. Climate-driven increases in fire and thermokarst may play a key role in OC mobilization by thawing permafrost and promoting transport of OC. Yet, the extent of OC mobilization and mechanisms controlling terrestrial-aquatAuthorsJoshua C. Koch, Matthew Bogard, David Butman, Kerri Finlay, Brian A. Ebel, Jason James, Sarah Ellen Johnston, Torre Jorgenson, Neal Pastick, Rob Spencer, Rob Striegl, Michelle A. Walvoord, Kimberly WicklandMulti-year, spatially extensive, watershed-scale synoptic stream chemistry and water quality conditions for six permafrost-underlain Arctic watersheds
Repeated sampling of spatially distributed river chemistry can be used to assess the location, scale, and persistence of carbon and nutrient contributions to watershed exports. Here, we provide a comprehensive set of water chemistry measurements and ecohydrological metrics describing the biogeochemical conditions of permafrost-affected Arctic watersheds. These data were collected in watershed-wideAuthorsArial Shogren, Jay P. Zarnetske, Benjamin W. Abbott, Samuel P. Bratsman, Brian C. Brown, Michael P. Carey, Randy Fulweiber, Heather Greaves, Emma Haines, Frances Iannucci, Joshua C. Koch, Alex Medvedeff, Jonathan A. O'Donnell, Leika Patch, Brett Poulin, Tanner J. Williamson, William B. BowdenSeasonality of solute flux and water source chemistry in a coastal glacierized watershed undergoing rapid change: Wolverine Glacier watershed, Alaska
As glaciers around the world rapidly lose mass, the tight coupling between glaciers and downstream ecosystems is resulting in widespread impacts on global hydrologic and biogeochemical cycling. However, a range of challenges make it difficult to conduct research in glacierized systems and our knowledge of seasonally changing hydrologic processes and solute sources and signatures is limited. This iAuthorsAnna Bergstrom, Joshua C. Koch, Shad O'Neel, Emily BakerStorm-scale and seasonal dynamics of carbon export from a nested subarctic watershed underlain by permafrost
Subarctic catchments underlain by permafrost sequester a major stock of frozen organic carbon (C), which may be mobilized as the Arctic warms. Warming can impact C export from thawing soils by altering the depth and timing of runoff related to changing storm and fire regimes and altered soil thaw depths. We investigated C export in a first order headwater stream (West Twin Creek) and its receivingAuthorsJoshua C. Koch, Mark Dornblaser, Rob StrieglArctic insect emergence timing and composition differs across thaw ponds of varying morphology
Freshwater ponds provide habitats for aquatic insects that emerge and subsidize consumers in terrestrial ecosystems. In the Arctic, insects provide an important seasonal source of energy to birds that breed and rear young on the tundra. The abundance and timing of insect emergence from arctic thaw ponds is poorly understood, but understanding these fluxes is important, given the role of insects inAuthorsSarah M. Laske, Kirsty E. B. Gurney, Joshua C. Koch, Joel A. Schmutz, Mark S. WipfliNitrogen biogeochemistry in a boreal headwater stream network in interior Alaska
High latitude, boreal watersheds are nitrogen (N)-limited ecosystems that export large amounts of organic carbon (C). Key controls on C cycling in these environments are the biogeochemical processes affecting the N cycle. A study was conducted in Nome Creek, an upland headwater tributary of the Yukon River, and two first-order tributaries to Nome Creek, to examine the relation between seasonalAuthorsRichard L. Smith, Deborah A. Repert, Joshua C. Koch - Web Tools
Arctic Rivers Project: Connecting Indigenous knowledge and western science to strengthen collective understanding of the changing Arctic
The Arctic Rivers Project will weave together Indigenous knowledges, monitoring, and the modeling of climate, rivers (flows, temperature, ice), and fish to improve understanding of how Arctic rivers, ice transportation corridors, fish, and communities might be impacted by and adapt to climate change.
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*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