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Natalie K Day

Natalie is a Biologist with the Colorado Water Science Center

Natalie is a cross-disciplinary biologist working on the Colorado Plateau. She seeks to provide relevant information to land managers, policy makers, and the public. Some of her research interests include assessing the effects of land disturbance in drylands on regional hydrology, understanding controls on riverine algal blooms, and assessing long-term changes in streamflow and water quality. Natalie works to improve the sharing of information among different fields and conducts research that is collaborative and useful.

Professional Experience

  • Biologist, USGS-Colorado Water Science Center, Grand Junction, CO, Fall 2019-present

  • Biologist, USGS-Canyonland Research Station, Moab, UT, 2016-2019

  • Biological Field Technician, USGS-Canyonland Research Station, Moab, UT, 2010-2011

  • Research Assistant, Utah Water Research Lab, Logan, UT, 2009-2010

  • Research Assistant, Biogeochemistry Lab, Utah State University, Logan, UT, 2008-2009

  • Student Technician, National Science Foundation, Toolik Lake, AK, advised by George Kling, 2007

  • Student Technician, National Science Foundation, Hubbard Brook Experimental Forest, advised by Gene Likens , 2007

Education and Certifications

  • Master of Science in Biogeochemistry, the University of Wyoming, Laramie, WY, 2015
    Focus: Nitrogen cycling in headwater streams in Rocky Mountain National Park, CO
    Advised by Robert O. Hall, Jr.

  • Bachelor of Arts in Biology, Lewis & Clark College, Portland, OR, 2008
    Focus: Aquatic biogeochemistry

Science and Products

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Image: Endangered Humpback Chub

Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
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Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
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Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
Learn More
link
Image: Endangered Humpback Chub

Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
By
Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
link

Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
Learn More
link
Image: Endangered Humpback Chub

Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
By
Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
link

Assessment of Mercury and Selenium Accumulation in Upper Colorado River Basin Fish

More than 50 years of existing mercury and selenium concentrations in native and nonnative fish species residing in streams within the Upper Colorado River Basin were compiled and analyzed to provide an understanding of concentrations among different species, sampling years, and locations to determine potential health risks. Concentrations of mercury and selenium were above health benchmarks in 13...
Learn More
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Image: Yampa River Basin, Colorado

Characterization of Streamflow, Suspended Sediment, and Nutrients in the Upper Yampa River Basin

The Upper Yampa River Basin (UYRB) drains approximately 1,800 square miles west of the Continental Divide in northwestern Colorado. In 2019, the USGS, in cooperation with local stakeholders in the UYRB water community, initiated a study to characterize streamflow, suspended sediment, and nutrients using historic and recently acquired water-quality data from a long-term monitoring program initiated...
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Colorado Water Science Center
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Characterization of Streamflow, Suspended Sediment, and Nutrients in the Upper Yampa River Basin

The Upper Yampa River Basin (UYRB) drains approximately 1,800 square miles west of the Continental Divide in northwestern Colorado. In 2019, the USGS, in cooperation with local stakeholders in the UYRB water community, initiated a study to characterize streamflow, suspended sediment, and nutrients using historic and recently acquired water-quality data from a long-term monitoring program initiated...
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Erosion rates and salinity and selenium yields in a basin near Rangely, Colorado following the 2017 Dead Dog wildfire as modeled by WEPP and measured from UAV

This data release accompanies a U.S Geological Survey study that assessed sediment, salinity, and selenium yields following the Dead Dog wildfire in northwestern Colorado. The Dead Dog fire ignited on June 11, 2017, near Rangely, Colorado, and burned over 17,000 acres, including the B2 study area. Two methodologies were used to quantify erosion and associated salinity and sediment yields in the B2
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Northern Rocky Mountain Science Center

Channel Characteristics, benthic algae, and water quality model data for selected sites in the upper White River Basin, Colorado, 2018-21

This U.S. Geological Survey (USGS) data release provides benthic algae and stream channel characteristics data collected from 20 water-quality sites in the Upper White River Basin, Colorado., during 2018-2021. Also included are input and output data from streamflow and water-quality regression models used to characterize streamflow and water-quality conditions at 3 sites in the Upper White River B
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Colorado Water Science Center

Channel Characteristics, benthic algae, and water quality model data for selected sites in the upper White River Basin, Colorado, 2018-21

This U.S. Geological Survey (USGS) data release provides benthic algae and stream channel characteristics data collected from 20 water-quality sites in the Upper White River Basin, Colorado., during 2018-2021. Also included are input and output data from streamflow and water-quality regression models used to characterize streamflow and water-quality conditions at 3 sites in the Upper White River B
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Colorado Water Science Center

Orthoimagery, digital elevation, digital terrain, final surface, and vegetation classification models for four stream catchments in western Colorado 2016

Unmanned Aerial System (UAS) flights were conducted over four stream catchments in Rio Blanco County, Colorado, during the summer of 2016. Two sties had active oil and gas operations within the basin whereas the other two sites did not. Structure from motion (SfM) was used to align raw images and create a dense point cloud, georectified orthoimage, and Digital Elevation Model (DEM) for each basin.
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Colorado Water Science Center

Input and output data from streamflow and water-quality regression models used to characterize streamflow and water-quality conditions in the Upper Yampa River Basin, Colorado, from 1992-2018

This dataset includes input and output data from streamflow and water-quality regression models used to characterize streamflow and water-quality conditions in the Upper Yampa River Basin, Colorado from 1999-2018. All input data, including discrete and continuous streamflows and discrete concentrations of suspended sediment, Kjeldahl nitrogen, and total phosphorus, were compiled from the U.S. Geol
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Colorado Water Science Center

Surrogate regression models for computation of time series suspended-sediment concentrations at Muddy Creek above Paonia Reservoir, Anthracite Creek above mouth near Somerset, and North Fork Gunnison below Raven Gulch near Somerset, Colorado

This model archive summary documents the surrogate regression model used to compute suspended-sediment concentrations at Muddy Creek above Paonia Reservoir, CO, USGS site number 385903107210800. The methods used follow U.S. Geological Survey (USGS) guidance as referenced in relevant Office of Surface Water Technical Memorandum (TM) 2016.07 and Office of Water Quality TM 2016.10, and USGS Technique
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Colorado Water Science Center

Fish tissue mercury and selenium concentrations in Upper Colorado River Basin: 1962-2011

These data were compiled to study mercury and selenium concentrations in fish species and assemblages in lotic waterbodies across the Upper Colorado River Basin. Data were compiled from State and Federal agencies. This data table contains raw concentration data, as well as standardized concentrations corrected for differences based on sample type (i.e., tissue type), species-specific bioaccumulati
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Southwest Biological Science Center

Investigation of potential factors controlling benthic algae in the upper White River Basin, Colorado, 2018–21

Nuisance levels of benthic filamentous green algae are becoming increasingly common in surface waters of Colorado and the western United States. In 2018 the U.S. Geological Survey began a study in cooperation with the White River and Douglas Creek Conservation Districts, Colorado River Basin Salinity Control Forum, and the Colorado River Water Conservation District to collect and analyze physical,
Authors
Natalie K. Day, Mark F. Henneberg
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Ecosystems Mission Area, Water Resources Mission Area, Southwest Biological Science Center, Colorado Water Science Center

Potential factors controlling benthic algae in the upper White River Basin, Colorado, 2018–21

Nuisance levels of benthic algae are becoming increasingly common in surface waters of the western United States and can compromise aesthetic quality, limit recreational activities, block water infrastructure, and negatively affect aquatic life. In cooperation with the White River and Douglas Creek Conservation Districts, the Colorado River Basin Salinity Control Forum, and the Colorado River Wate
Authors
Rachel G. Gidley, Natalie K. Day
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Ecosystems Mission Area, Water Resources Mission Area, Southwest Biological Science Center, Colorado Water Science Center

Characterization of streamflow and nutrient occurrence in the upper White River Basin, Colorado, 1980–2020

In 2016, Colorado Parks and Wildlife identified filamentous algae collected from the main stem White River as Cladophora glomerata, a pervasive nuisance aquatic alga. Excessive levels of filamentous algae can compromise aesthetic quality, limit recreational activities, and have negative effects on aquatic life including strong fluctuations in dissolved oxygen levels and a reduction in overall biod
Authors
Natalie K. Day
By
Ecosystems Mission Area, Water Resources Mission Area, Southwest Biological Science Center, Colorado Water Science Center

A review of current capabilities and science gaps in water supply data, modeling, and trends for water availability assessments in the Upper Colorado River Basin

The Colorado River is a critical water resource in the southwestern United States, supplying drinking water for 40 million people in the region and water for irrigation of 2.2 million hectares of land. Extended drought in the Upper Colorado River Basin (UCOL) and the prospect of a warmer climate in the future pose water availability challenges for those charged with managing the river. Limited wat
Authors
Fred D. Tillman, Natalie K. Day, Matthew P. Miller, Olivia L. Miller, Christine Rumsey, Daniel Wise, Patrick Cullen Longley, Morgan C. McDonnell
By
Ecosystems Mission Area, Water Resources Mission Area, Arizona Water Science Center, Southwest Biological Science Center, Utah Water Science Center

Analysis of Escherichia coli, total recoverable iron, and dissolved selenium concentrations, loading, and identifying data gaps for selected 303(d) listed streams, Grand Valley, western Colorado, 1980–2018

Tributaries to the Colorado River in the Grand Valley in western Colorado (segment COLCLC13b) have been placed on the State of Colorado 303(d) list as impaired for Escherichia coli (E. coli), total recoverable iron, and dissolved selenium. The Colorado Department of Public Health and Environment Water Quality Control Division is required to develop total maximum daily loads for these constituents
Authors
Lisa D. Miller, Rachel G. Gidley, Natalie K. Day, Judith C. Thomas
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Ecosystems Mission Area, Water Resources Mission Area, Colorado Water Science Center, Southwest Biological Science Center

Assessment of streamflow and water quality in the Upper Yampa River Basin, Colorado, 1992–2018

The Upper Yampa River Basin drains approximately 2,100 square miles west of the Continental Divide in north-western Colorado. There is a growing need to understand potential changes in the quantity and quality of water resources as the basin is undergoing increasing land and water development to support growing municipal, industrial, and recreational needs. The U.S. Geological Survey, in cooperati
Authors
Natalie K. Day
By
Water Resources Mission Area, Colorado Water Science Center

Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment

Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962–2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in
Authors
Natalie K. Day, Travis Schmidt, James Roberts, Barbara C. Osmundson, James Willacker, Collin Eagles-Smith
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Ecosystems Mission Area, Colorado Water Science Center, Southwest Biological Science Center

Microsite enhancements for soil stabilization and rapid biocrust colonization in degraded drylands

In dryland ecosystems, natural recovery of biological soil crusts (biocrusts) following disturbance may be slow or inhibited, necessitating active restoration practices. While biocrusts can be readily propagated under environmentally controlled conditions, rehabilitation in the field is complicated by environmental stresses which may be particularly acute in degraded, destabilized soils with harsh
Authors
Stephen E. Fick, Natalie K. Day, Michael C. Duniway, Sean Lawrence Hoy-Skubik, Nichole N. Barger
By
Ecosystems Mission Area, Southwest Biological Science Center

Amendments fail to hasten biocrust recovery or soil stability at a disturbed dryland sandy site

In most drylands, biological soil crusts (biocrusts), an assemblage of lichens, bryophytes, fungi, green algae, and cyanobacteria, are critical to healthy ecosystem function. However, they are extremely sensitive to disturbance and attempts to facilitate their recovery have had variable success. In this study, we applied soil amendments designed to improve soil surface stability and accelerate bio
Authors
David G. Chandler, Natalie K. Day, Matthew D. Madsen, Jayne Belnap
By
Ecosystems Mission Area, Climate Research and Development Program, Land Change Science Program, Southwest Biological Science Center

Non-USGS Publications**

Tillman, Fred D, Natalie K. Day, Matthew P. Miller, Olivia L. Miller, Christine A. Rumsey, Daniel R. Wise, Patrick C. Longley, and Morgan C. McDonnell. 2022. "A Review of Current Capabilities and Science Gaps in Water Supply Data, Modeling, and Trends for Water Availability Assessments in the Upper Colorado River Basin" Water 14, no. 23: 3813. https://doi.org/10.3390/w14233813
Sutfin, N.A., Wohl, E., Fegel, T., Day, N., Lynch, L., 2021. Logjams and Channel Morphology Influence Sediment Storage, Transformation of Organic Matter, and Carbon Storage Within Mountain Stream Corridors. Water resources research. v. 57(5), https://doi.org/10.1029/2020WR028046
Fick, S.E., Day, N., Duniway, M.C., Hoy‐Skubik, S. and Barger, N.N., 2019. Microsite enhancements for soil stabilization and rapid biocrust colonization in degraded drylands. Restoration Ecology.
Tucker, C., Antoninka, A., Day, N., Poff, B. and Reed, S., 2020. Biological soil crust salvage for dryland restoration: an opportunity for natural resource restoration. Restoration Ecology.
Amendments fail to hasten biocrust recovery or soil stability at a disturbed dryland sandy site
Day, N.K., Hall Jr, R.O. 2017. Ammonium uptake kinetics and nitrification in mountain streams. Freshwater Science v. 36.1, p. 41-54.
Day, N.K., Likens, G.E., Judd, K.E., 2006. Nitrogen cycling in streams: A comparison of the roles of debris dams and mosses. Institute of Ecosystem Studies.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Science and Products