Christopher Konrad is a research hydrologist with U.S. Geological Survey in Tacoma, Washington.
His research integrates data collected from ground-based observations and networks, aircraft, and satellites with quantitative analysis and model development to address key scientific questions for environmental management. Dr. Konrad’s expertise spans many topics in the field of hydrology: streamflow, floods, and drought; hydraulics and fluvial sediment transport; groundwater and surface water interactions; and the effects of water management and land use on river ecosystems. Dr. Konrad served as the River Science Coordinator for The Nature Conservancy and USGS from 2007 to 2011 working on the development and evaluation of ecological flow requirements for rivers. He earned a BS in Biological Sciences from Stanford University and MS and PhD in Civil and Environmental Engineering from the University of Washington.
Science and Products
Water Availability for Tribal Treaty Rights in Western Washington
Analysis of USGS Surface Water Monitoring Networks
USGS science supporting the Elwha River Restoration Project
River Corridor hot spots for biogeochemical processing: a continental scale synthesis
Cedar River Peak Flow Management
NWIFC Water Assessment
Green River Geomorphic Responses
Elwha River
GW/SW Interactions
Methow River Basin
Hydrologic Urban Indicators
Network Analysis of USGS Streamflow Gages (ver. 2.0, May 2023)
Network Analysis of USGS Streamflow Gages
Non-linear baseflow separation model with parameters and results (ver. 2.0, October 2022)
Attributions for nonstationary peak streamflow records across the conterminous United States, 1941-2015 and 1966-2015
Basin characteristics and travel time metrics for 100 sites in the southeastern United States
Water-quality and stream-habitat metrics calculated for the National Water-Quality Assessment Program's Regional Stream Quality Assessment conducted in the southeast United States in support of ecological and habitat stressor models, 2014
RockType to Permeability Crosswalk Table, Northwest U.S.
Measures of the vulnerability of runoff to drought during 2015 in the western United States
Longitudinal profile and off-channel habitats of the lower Cedar River, Washington
Factors related to the sediment balance of 97 streams in the Midwestern US
BFS—A non-linear, state-space model for baseflow separation and prediction
Assessment and significance of the frequency domain for trends in annual peak streamflow
Multiple in-stream stressors degrade biological assemblages in five U.S. regions
Inclusion of pesticide transformation products is key to estimating pesticide exposures and effects in small U.S. streams
Accounting for temporal variability of streamflow in estimates of travel time
Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery
Spectral analysis to quantify the response of groundwater levels to precipitation — Northwestern United States
Flow modification in the Nation’s streams and rivers
A conceptual framework for the identification and characterization of lacustrine spawning habitats for native lake charr Salvelinus namaycush
Benthic algal (Periphyton) growth rates in response to nitrogen and phosphorus: Parameter estimation for water quality models
Estimating minimum streamflow from measurements at ungauged sites in regions with streamflow‐gauging networks
Seasonal precipitation influences streamflow vulnerability to the 2015 drought in the western United States
Streamflow monitoring network analysis
US Geological Survey operates a streamflow monitoring network that extends across the United States and its territories. The network was analyzed systematically by Konrad and others (2022) for its coverage, resolution, and representation of a wide range of public interests in streamflow information The results can be used to identify priority areas for continued or expanded monitoring.
Science and Products
- Science
Water Availability for Tribal Treaty Rights in Western Washington
The Issue: Native American treaty rights depend on the availability of adequate and high-quality streamflow across the Western Washington, which can be degraded by water and land use, reservoir operations, and climate change among other factors. Streamflow during critical low-flow periods depend on groundwater discharge from aquifers, which also is vulnerable to human activities in the Western...Analysis of USGS Surface Water Monitoring Networks
The issue: National interests in water information are important but challenging to incorporate into planning and operation of a monitoring network driven by local information needs. These interests include an understanding of the spatial variability in water availability across the United States, anthro-physical factors including climate and land use that affect water availability, and federal...USGS science supporting the Elwha River Restoration Project
The Elwha River Restoration Project has reconnected the water, salmon, and sediment of a pristine river and coast of the Olympic Peninsula of Washington.River Corridor hot spots for biogeochemical processing: a continental scale synthesis
Rivers are the veins of the landscape, providing environmental benefits that are disproportionately high relative to their aerial extent; shedding flood waters, hosting aquatic ecosystems, transporting solutes and energy-rich materials, and storing and transforming pollutants into less harmful forms. From uplands to the coasts, rivers facilitate key biogeochemical reactions that cumulatively influCedar River Peak Flow Management
The Cedar River watershed provides two-thirds of the water supply for the greater Seattle metropolitan region, in addition to being home to numerous federally listed salmon species. The City of Seattle, through Seattle Public Utilities (SPU), works closely with the Cedar River Instream Flow Commission (IFC) to adaptively manage flows on the Cedar River. Seattle operates its water management...NWIFC Water Assessment
Water resources are essential to Native American Tribes in western Washington for instream and out-of-stream uses. As the demand for water across the region increases, western Washington Tribes need critical information about water availability, water use, and ecological needs for water in order to manage their resources. To assess tribal water resources comprehensively in western Washington, the...Green River Geomorphic Responses
In the Pacific Northwest, water, sediment, and vegetation primarily determine the form of large river channels and shape their ecosystems. Dams on rivers affect all of these elements, with consequences for habitats and aquatic species. Understanding how water, sediment, and vegetation interact in habitats is key to managing rivers. In the case of the middle Green River in King County, Washington...Elwha River
The formerly free-flowing Elwha River was famous for the diversity and size of its salmon runs. After the construction of the Elwha Dam (1912) and the Glines Canyon Dam (1927), fish lost access to more than 70 miles of mainstem river and tributary habitat. As a result, all 10 runs of native Elwha salmon and sea-going trout declined sharply. Restoration of the Elwha River ecosystem will be...GW/SW Interactions
Knowing the interactions of ground water and river water can help reduce the fluctuation of water supplies in alluvial (sediment-deposit) river basins. To develop general principles of these interactions in order to identify and analyze them, the USGS is reviewing the results of the numerous studies of these interactions in Pacific Northwest basins. The review will describe common geologic aspects...Methow River Basin
The Methow River Basin, located in North Central Washington in Okanogan County, is well known for its natural beauty, wildlife, outdoor recreation, and rural lifestyle. The Methow River and its tributaries are home to upper Columbia summer steelhead and spring Chinook salmon, which are both listed as endangered under the Endangered Species Act (ESA), and bull trout, which is listed as threatened...Hydrologic Urban Indicators
Storm water, the rainfall that runs off urban surfaces such as rooftops, pavement, and lawns, can affect streams in a number of ways. As urban development increases, storm water can run quickly into streams, increasing the volume and peak flows and reducing summer flows. Sediment and other contaminants can also be carried into the streams. The Washington Department of Ecology (WDOE), the state... - Data
Network Analysis of USGS Streamflow Gages (ver. 2.0, May 2023)
This data release has a workflow, data, and results of an analysis of the coverage, resolution, and representation of variables related to public interests in streamflow information by the USGS streamflow gaging network that was active in water year 2020. The workflow for the analysis is implemented as scripts and functions in the statistical programming language R. The spatial framework for the aNetwork Analysis of USGS Streamflow Gages
This data release has components of an analysis of the coverage, resolution, and representation of national public interests in streamflow information by the USGS streamflow gaging network that was active in water year 2020. The workflow for the analysis is implemented as scripts and functions in the statistical programming language R. The spatial framework for the analysis is based on from the NaNon-linear baseflow separation model with parameters and results (ver. 2.0, October 2022)
This data release provides source code and an R workspace with functions comprising a non-linear baseflow separation model, calibrated values of parameters and estimates of the baseflow component of daily streamflow at selected streamflow gages. Parameter values were determined by calibration of the model. Estimates of the baseflow component include daily values and the total baseflow as a fractioAttributions for nonstationary peak streamflow records across the conterminous United States, 1941-2015 and 1966-2015
The U.S. Geological Survey Dakota Water Science Center, in cooperation with the Federal Highway Administration, analyzed annual peak-flow data to determine if trends are present and provide attribution of trends where possible. Work for the national trend attributions for nonstationary annual peak-flow records was broken into seven regions that are loosely based off of two-digit hydrologic unit waBasin characteristics and travel time metrics for 100 sites in the southeastern United States
The dataset has basin characteristics (drainage area, land use, and reservoir storage), parameters for a relation between streamflow and velocity, and travel time metrics at 100 gaged sites in the southeastern United States.Water-quality and stream-habitat metrics calculated for the National Water-Quality Assessment Program's Regional Stream Quality Assessment conducted in the southeast United States in support of ecological and habitat stressor models, 2014
This data release includes metrics from the Regional Stream Quality Assessment (RSQA) from the Southeast Region for habitat stressors related to water-quality and habitat substrate. The goals of RSQA are to characterize multiple water-quality factors that are stressors to aquatic life -- contaminants, nutrients, sediment, and streamflow alteration -- and to develop a better understanding of the reRockType to Permeability Crosswalk Table, Northwest U.S.
This table is a crosswalk or lookup table that classifies rock type (surface geology) by its permeability, or the ability to pass substances, such as liquids or gases. The rock types that are classified are located in the Northwest U.S. -- Oregon, Washington, Idaho, Utah, Nevada, Wyoming, and Montana.Measures of the vulnerability of runoff to drought during 2015 in the western United States
Measures used to assess the vulnerability of streamflow in 326 river basins to the 2015 drought in the western United States.Longitudinal profile and off-channel habitats of the lower Cedar River, Washington
Alcoves and side channels along the Cedar River, Washington from Landsburg to Lake Washington mapped on June 11-12, 2013 during a field survey. Data are provided as ESRI ArcMap shapefiles.Factors related to the sediment balance of 97 streams in the Midwestern US
Physical attributes of 97 streams in the Midwestern US characterizing sediment supply, sediment transport capacity, and stream bed material. Attributes include basin characteristics compiled with geographic information system and statistical summaries of field measurements of channel form, bed material, and suspended sediment. Data were used by Konrad and Gellis, 'Factors influencing fine sediment - Publications
Filter Total Items: 50
BFS—A non-linear, state-space model for baseflow separation and prediction
Streamflow in rivers can be separated into a relatively steady component, or baseflow, that represents reliably available surface water and more dynamic components of runoff that typically represent a large fraction of total streamflow. A spatially aggregated numerical time-series model was developed to separate the baseflow component of a streamflow time-series using a state-space framework in whAuthorsChristopher P. KonradAssessment and significance of the frequency domain for trends in annual peak streamflow
Risk management of nonstationary floods depends on an understanding of trends over a range of flood frequencies representing small (frequent) to large (infrequent) floods. Quantile regression is applied to the annual peak streamflow distributions at 2683 sites in the contiguous United States to test for trends in the 10th quantile (floods with a 0.9 annual exceedance probability), the 50th quantilAuthorsChristopher P. Konrad, Daniel Edmund RestivoMultiple in-stream stressors degrade biological assemblages in five U.S. regions
Biological assemblages in streams are affected by a wide variety of physical and chemical stressors associated with land-use development, yet the importance of combinations of different types of stressors is not well known. From 2013 to 2017, the U.S. Geological Survey completed multi-stressor/multi-assemblage stream ecological assessments in five regions of the United States (434 streams total).AuthorsIan R. Waite, Peter C. Van Metre, Patrick W. Moran, Christopher P. Konrad, Lisa H. Nowell, Michael R. Meador, Mark D. Munn, Travis S. Schmidt, Allen Gellis, Daren Carlisle, Paul M. Bradley, Barbara MahlerByEcosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, California Water Science Center, Kansas Water Science Center, Oklahoma-Texas Water Science Center, Oregon Water Science Center, South Atlantic Water Science Center (SAWSC), Washington Water Science Center, Wyoming-Montana Water Science CenterInclusion of pesticide transformation products is key to estimating pesticide exposures and effects in small U.S. streams
Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosystems remains limited. We quantified 108 parent pesticides and 116 TPs in more than 3 700 samples from 442 small streams in mostly urban basins across five major regions of the United States. TPs were detected nearly as frequently aAuthorsBarbara Mahler, Lisa H. Nowell, Mark W. Sandstrom, Paul Bradley, Kristin Romanok, Christopher Konrad, Peter Van MetreByEcosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, California Water Science Center, New Jersey Water Science Center, Oklahoma-Texas Water Science Center, South Atlantic Water Science Center (SAWSC), Washington Water Science Center, National Water Quality LaboratoryAccounting for temporal variability of streamflow in estimates of travel time
Retention, processing, and transport of solutes and particulates in stream corridors are influenced by the travel time of streamflow through stream channels, which varies dynamically with discharge. The effects of streamflow variability across sites and over time cannot be addressed by time-averaged models if parameters are based solely on the characteristics of mean streamflow. We develop methodsAuthorsChristopher P. Konrad, Noah Schmadel, Judson Harvey, Gregory E. Schwarz, Jesus Gomez-Velez, Elizabeth W. Boyer, Durelle ScottLow threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery
River corridors store, convey, and process nutrients from terrestrial and upstream sources, regulating delivery from headwaters to estuaries. A consequence of chronic excess nitrogen loading, as supported by theory and field studies in specific areas, is saturation of the biogeochemically-mediated nitrogen removal processes that weakens the capacity of the river corridor to remove nitrogen. RegionAuthorsNoah Schmadel, Judson Harvey, Richard Alexander, Elizabeth W. Boyer, Gregory E. Schwarz, Jesus D. Gomez-Velez, Durelle Scott, Christopher KonradSpectral analysis to quantify the response of groundwater levels to precipitation — Northwestern United States
Persistent atmospheric patterns that lead to wet and dry seasons and droughts over periods of months to decades and longer-term climate change over periods of decades to millennia affect groundwater resources. Changes in groundwater storage and the resulting groundwater discharge from most aquifers is relatively slow and steady compared to the variability of daily precipitation. The response of grAuthorsAndrew J. Long, Christopher P. KonradFlow modification in the Nation’s streams and rivers
This report summarizes a national assessment of flowing waters conducted by the U.S. Geological Survey’s (USGS) National Water-Quality Assessment (NAWQA) Project and addresses several pressing questions about the modification of natural flows in streams and rivers. The assessment is based on the integration, modeling, and synthesis of monitoring data collected by the USGS and the U.S. EnvironmentaAuthorsDaren Carlisle, David M. Wolock, Christopher P. Konrad, Gregory J. McCabe, Ken Eng, Theodore E. Grantham, Barbara MahlerA conceptual framework for the identification and characterization of lacustrine spawning habitats for native lake charr Salvelinus namaycush
Lake charr Salvelinus namaycush are endemic to the formerly glaciated regions of North America and spawn primarily in lakes, unlike most other Salmoninae. Spawning habitats for lake charr are thought to be characterized by relatively large substrate particle sizes which provide sufficient interstitial spaces for egg incubation, but little is known about the physical processes that create or maintaAuthorsStephen Riley, J. E. Marsden, M. S. Ridgway, Christopher Konrad, Steve A. Farha, Thomas R. Binder, Trevor A. Middel, Peter Esselman, Charles C. KruegerBenthic algal (Periphyton) growth rates in response to nitrogen and phosphorus: Parameter estimation for water quality models
Nitrogen (N) and phosphorus (P) are important pollutants that can stimulate nuisance blooms of algae. Water-quality models (e.g., WASP, CE-QUAL-R1, CE-QUAL-ICM, QUAL2k) are valuable and widely used management tools for algal accrual because of excess nutrients in the presence of other limiting factors. These models utilize the Monod and Droop equations to associate algal growth rate with dissolvedAuthorsTravis S. Schmidt, Christopher Konrad, Janet L. Miller, Stephen D. Whitlock, Craig A. StrickerEstimating minimum streamflow from measurements at ungauged sites in regions with streamflow‐gauging networks
Estimation of low flows in rivers continues to be a vexing problem despite advances in statistical and process‐based hydrological models. We develop a method to estimate minimum streamflow at seasonal to annual timescales from measured streamflow based on regional similarity in the deviations of daily streamflow from minimum streamflow for a period of interest. The method is applied to 1,019 gaugeAuthorsChristopher P. KonradSeasonal precipitation influences streamflow vulnerability to the 2015 drought in the western United States
Streamflow was exceptionally low in the spring and summer of 2015 across much of the western United States because of a regional drought that exploited the sensitivity of both snow- and rain-dominant rivers. Streamflow during 2015 was examined at 324 gauges in the region to assess its response to the amount, form, and seasonal timing of precipitation and the viability of using spatially aggregatedAuthorsChristopher Konrad - News
- Web Tools
Streamflow monitoring network analysis
US Geological Survey operates a streamflow monitoring network that extends across the United States and its territories. The network was analyzed systematically by Konrad and others (2022) for its coverage, resolution, and representation of a wide range of public interests in streamflow information The results can be used to identify priority areas for continued or expanded monitoring.