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Articles 841 - 870 of 2388

Full-Text Articles in Fresh Water Studies

Umphlett Qci Sept 2016, Natalie Umphlett Sep 2016

Umphlett Qci Sept 2016, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Streamflow Conditions

Challenging Season for Bird Breeding

Mixed Impacts to Agriculture this Summer

Unprecedented Fish Kill on Yellowstone River

3-Month Precipitation and Temperature Outlooks

Soil Moisture Conditions


Tidal-Fluvial And Estuarine Processes In The Lower Columbia River: Ii. Water Level Models, Floodplain Wetland Inundation, And System Zones, David A. Jay, Amy B. Borde, Heida Diefenderfer Sep 2016

Tidal-Fluvial And Estuarine Processes In The Lower Columbia River: Ii. Water Level Models, Floodplain Wetland Inundation, And System Zones, David A. Jay, Amy B. Borde, Heida Diefenderfer

Civil and Environmental Engineering Faculty Publications and Presentations

Spatially varying water-level regimes are a factor controlling estuarine and tidal-fluvial wetland vegetation patterns. As described in Part I, water levels in the Lower Columbia River and estuary (LCRE) are influenced by tides, river flow, hydropower operations, and coastal processes. In Part II, regression models based on tidal theory are used to quantify the role of these processes in determining water levels in the mainstem river and floodplain wetlands, and to provide 21-year inundation hindcasts. Analyses are conducted at 19 LCRE mainstem channel stations and 23 tidally exposed floodplain wetland stations. Sum exceedance values (SEVs) are used to compare wetland …


Presence Of The Cyanotoxin Microcystin In Arctic Lakes Of Southwestern Greenland, Jessica Trout-Haney, Zachary Wood, Kathryn Cottingham Aug 2016

Presence Of The Cyanotoxin Microcystin In Arctic Lakes Of Southwestern Greenland, Jessica Trout-Haney, Zachary Wood, Kathryn Cottingham

Dartmouth Scholarship

Cyanobacteria and their toxins have received significant attention in eutrophic temperate and tropical systems where conspicuous blooms of certain planktonic taxa release toxins into fresh water, threatening its potability and safe use for recreation. Although toxigenic cyanobacteria are not confined to high nutrient environments, bloom-forming species, or planktonic taxa, these other situations are studied les often studied. For example, toxin production in picoplankton and benthic cyanobacteria—the predominant photoautotrophs found in polar lakes—is poorly understood. We quantified the occurrence of microcystin (MC, a hepatotoxic cyanotoxin) across 18 Arctic lakes in southwestern Greenland. All of the focal lakes contained detectable levels of …


Velocity Profiling, Turbulence, And Chlorophyll Concentrations In The Bottom Boundary Layer Of Lake Michigan Near Muskegon, Michigan, Jonathan M. Benoit, Cary D. Troy, David J. Cannon Aug 2016

Velocity Profiling, Turbulence, And Chlorophyll Concentrations In The Bottom Boundary Layer Of Lake Michigan Near Muskegon, Michigan, Jonathan M. Benoit, Cary D. Troy, David J. Cannon

The Summer Undergraduate Research Fellowship (SURF) Symposium

The characterization of water flow and turbulence near lake beds is important for modelling environmental and ecological effects throughout a lake. In Lake Michigan, where invasive filter-feeding Quagga mussels dominate the lake bed, turbulence plays an important role in determining how much of chlorophyll is mixed down to the Quagga Mussels. Deep in Lake Michigan (44m) near Muskegon, MI, a large tripod was deployed, attached with an Acoustic Doppler Velocimeter, a fluorometer to measure chlorophyll concentrations, and a temperature sensor. Measurements were recorded from late May until early August by sampling velocities every hour in ten-minute bursts at 4 Hz, …


Analyzing Accuracy Of The Lufft Ws600 In Remotely Measuring Precipitation Events, Justin Gay Aug 2016

Analyzing Accuracy Of The Lufft Ws600 In Remotely Measuring Precipitation Events, Justin Gay

STAR Program Research Presentations

The goal of this project was to analyze the accuracy of the Lufft WS600 Weather Sensor in measuring the rate of both liquid and solid precipitation. Measurement accuracy, especially in remote locations, can be difficult to obtain and quantify. Wind, blowing debris, and atmospheric particles can all have the capacity to interfere with instruments that are not being continuously compared to manual observations. Access to quality precipitation data sets are important for both hydrologic and weather forecasting, climate monitoring, and understanding the role of water cycling through ecosystems. Commercially, weather sensors are heavily relied upon by the Federal Aviation Administration …


Optical Water Quality And Human Perceptions Of Rivers, Amie West Aug 2016

Optical Water Quality And Human Perceptions Of Rivers, Amie West

Graduate Theses and Dissertations

Understanding water quality dynamics in recreational rivers is integral in shaping management strategies that maintain ecosystem health, perceived value and appeal, and regional economic significance in a changing environment. Optical water quality describes the behavior of light in water as governed by its physical and chemical composition, and is among the strongest influences on human perceptions of water quality. Ethnohydrology is the study of culturally constructed knowledge and understanding of water. This work is the culmination of an interdisciplinary approach to water resources research—integrating optical water quality and ethnohydrology methods to recognize the intersection between measured water quality and visible …


Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile Aug 2016

Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile

Graduate Theses and Dissertations

This study investigated the effects of source water quality in Beaver Lake on the amount of chlorine (Cl) needed to develop decision support system to help guide chlorination practices in pre-treatment of source water. Chlorine demand assays were performed on water samples from Beaver Lake collected from the intake structure at Beaver Water District from March 2014 through August 2015, and using data from these assays, the two points of interest in this study were the Cl dose at which Cl residuals began to accumulate and the mean Cl demand occurring after that dose. Three methods of analysis were used …


Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson Aug 2016

Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson

Graduate Theses and Dissertations

In the past decade, 29 shale basins have been actively developed across 20 states for extraction of natural gas (NG) via horizontal drilling/hydraulic fracturing (=fracking). This includes ~5000 wells within the Fayetteville shale of north-central Arkansas. Development often impacts both river- and landscapes, and management requires catchment-level evaluations over time, with organismal presence/absence as indicators. For this study next-generation sequencing was used to identify/characterize microbial communities within biofilm of eight Arkansas River tributaries, so as to gauge potential catchment influences. Streams spanned a gradient of landscape features and hydrological flows, with four serving as ‘potentially impacted catchment zones’ (PICZ) and …


Trend Analysis Of Water Quality In Northwest Arkansas Streams Reflects Changes In The Watershed, Zachary Paul Simpson Aug 2016

Trend Analysis Of Water Quality In Northwest Arkansas Streams Reflects Changes In The Watershed, Zachary Paul Simpson

Graduate Theses and Dissertations

Watershed export of nutrients, sediments, and chemicals impacts receiving waters. Changes within the watershed (e.g., anthropogenic or climatic) can alter the transport of constituents in streams. Stream monitoring is crucial for understanding these effects. This study developed a potential improvement to flow-adjusting constituent concentrations in streams, an important step of analyzing monitoring data in lotic systems for trends. The method incorporates a K-fold cross-validation procedure to optimize a model explaining the relationship between the concentration and streamflow, thus providing a valuable tool to researchers in water quality. Additionally, two case studies were conducted on watersheds located in northwest Arkansas using …


Biogeochemistry Of A Saline, Alkaline, Terminal Lake Ecosystem In Transition; Walker Lake, Nevada, Katherine Lynn Willever Aug 2016

Biogeochemistry Of A Saline, Alkaline, Terminal Lake Ecosystem In Transition; Walker Lake, Nevada, Katherine Lynn Willever

UNLV Theses, Dissertations, Professional Papers, and Capstones

Walker Lake is a saline, alkaline, terminal lake ecosystem located in west-central Nevada. For over one hundred years, anthropogenic streamflow diversions within the Walker River Basin have ultimately led to little or no water reaching Walker Lake, the basin’s terminus for water flow. These diversions have resulted in a >46 meter decrease in the lake surface altitude and increases in salinity and dissolved salt constituents that have caused the elimination of native fish species. This study examines how the lack of freshwater inflow has altered the physical, chemical, and microbiological structure of Walker Lake during the lake’s ongoing desiccation.

Between …


Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise Aug 2016

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …


Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers Aug 2016

Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers

Graduate Theses and Dissertations

Electrodeionization (EDI) is a widely studied process ranging from applications in wastewater clean-up in the food and beverage industry to purifying organic compounds. To date, there are no apparent studies on applying this technology to produced wastewater recovered from hydraulic fracking sites. Water consumption within hydraulic fracturing sites can reach in the upwards of millions of gallons per site, so a need for a water recycling process becomes necessary within areas where water requirements are scarce. Implementation of an EDI module that is capable of handling high salt solutions from produced wastewater in subsequent fracturing practices will decrease overall water …


Overview Of The Phytoplankton And Water Quality Of Lake Maumelle For 2009, Rich Shaver Jul 2016

Overview Of The Phytoplankton And Water Quality Of Lake Maumelle For 2009, Rich Shaver

Theses and Dissertations

Since 1989 the United States Geological Survey (USGS) and Central Arkansas Water (CAW) have collected water quality and phytoplankton samples from Lake Maumelle in Central Arkansas. These samples were collected from three locations within the reservoir. Phytoplankton samples for 2009 were identified to genus and counted. The phytoplankton did not follow a typical succession pattern for north temperate lakes. Starting in late winter, Chlorophyta tended to be the dominant division followed by Cyanophyta in the fall. Diversity was relatively high at all sampling locations and no differences among sites were detected. Total phosphorus appeared to be the limiting nutrient. Based …


Drougthscape, Summer 2016, National Drought Mitigation Center Jul 2016

Drougthscape, Summer 2016, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

NDMC adds two employees

Second quarter drought summary: Drought slowly spreading

Second quarter drought impacts: Drought intensifies across US

First comprehensive drought

indices guidebook released

Drought Impact Reporter updates increase usability

Create a custom DIR view

Drought center co-leads MENA region project

McCook, Nebraska, tackles drought resilience

Arizona groups improve public lands drought planning

NDMC founder Don Wilhite retires


Bella Vista Lakes Project: Fertility Management, J. Thad Scott Jun 2016

Bella Vista Lakes Project: Fertility Management, J. Thad Scott

Arkansas Water Resources Center Technical Reports

No abstract provided.


Umphlett Qci June 2016, Natalie Umphlett Jun 2016

Umphlett Qci June 2016, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Snowpack and Streamflow

Limited Frost Damage to Crops this Spring

Wet Conditions Cause Mixed Impacts

3-Month Precipitation and Temperature Outlooks

U.S. Seasonal Drought Outlook


Cockatoo Sands In The Victoria Highway And Carlton Hill Areas, East Kimberley: Hydrogeology, Aquifer Properties And Groundwater Chemistry, D L. Bennett, John Andrew Simons, Richard J. George Dr, Paul Raper May 2016

Cockatoo Sands In The Victoria Highway And Carlton Hill Areas, East Kimberley: Hydrogeology, Aquifer Properties And Groundwater Chemistry, D L. Bennett, John Andrew Simons, Richard J. George Dr, Paul Raper

Resource management technical reports

Cockatoo Sands are recognised as potentially suitable for irrigated agriculture because they are generally well drained and not subject to waterlogging or inundation. These characteristics allow them to be cultivated and prepared for planting various crops during the wet and dry seasons of northern Australia. Expanding agricultural production onto the Cockatoo Sands around Kununurra will increase opportunities for agriculture by increasing the overall scale of agriculture, allowing year-round agricultural enterprise, new crops and new market opportunities.

DAFWA has assessed the soil characteristics and agriculturally suitable areas of Cockatoo Sands in the Victoria Highway and Carlton Hill areas near Kununurra. Potential …


Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson May 2016

Dietary Effects On The Stoichiometry Of Growth, Regulation, And Wastes Of Ozark Stream Insect Detritivores, Halvor Matthew Halvorson

Graduate Theses and Dissertations

A widespread stressor, anthropogenic nitrogen (N) and phosphorus (P) pollution can increase resource nutrient content and alter animal community composition in freshwater ecosystems. In this dissertation, I used ecological stoichiometry theory to examine effects of diet nutrient content and leaf litter type on growth, regulation, and wastes of aquatic invertebrate detritivores. I tested effects of leaf litter diet carbon:phosphorus (C:P) on growth and stoichiometric regulation of the detritivorous caddisfly Pycnopsyche lepida and used results to determine a threshold elemental ratio of oak litter C:P=1620 that confers peak growth of this species. This empirical, growth-based approach provided a more accurate estimate …


Drinking Water Treatment: Salt-Free Water “Softener” Options, Bruce I. Dvorak May 2016

Drinking Water Treatment: Salt-Free Water “Softener” Options, Bruce I. Dvorak

Department of Civil and Environmental Engineering: Faculty Publications

New no-salt technologies may be effective in treating hard water, but consumers should carefully investigate product claims prior to buying a specific treatment device.

Hard water is not a health risk, but many Nebraska consumers find hard water to be a nuisance because of mineral buildup on plumbing fixtures, including water heaters; unsightly film on glass and crystal wares; and poor soap and/or detergent performance. Water described as “hard” contains high amounts of dissolved calcium and magnesium, which are positively charged contaminants called cations.

Water hardness often is expressed as grains of hardness per gallon of water (gpg) or milligrams …


The Role Of Hydrologic Regimes In Driving Morphologic Divergence And The Trait Compositions Of Fish Assemblages, Lindsey A. Bruckerhoff May 2016

The Role Of Hydrologic Regimes In Driving Morphologic Divergence And The Trait Compositions Of Fish Assemblages, Lindsey A. Bruckerhoff

Graduate Theses and Dissertations

The hydrologic regime is an important determinant of the ecological integrity of a stream. Hydrologic regimes are defined by the magnitude, timing, frequency, rate of change, and duration of high and low flow events and capture long term patterns of variability and predictability of water movement in a stream. Flow regimes influence many aspects of the biophysical environment in lotic systems; therefore organisms have adapted to natural flow patterns. We investigated how fish have adapted to flow regimes at both a population and community level. In the first study presented in this thesis, we hypothesized fish exhibit phenotypic divergence to …


A Method Comparison And Stressor-Response Experimental Study Of Nitrogen And Phosphorus Impacts To Periphyton In Ozark Streams, Ashley Renee Rodman May 2016

A Method Comparison And Stressor-Response Experimental Study Of Nitrogen And Phosphorus Impacts To Periphyton In Ozark Streams, Ashley Renee Rodman

Graduate Theses and Dissertations

Stream bioassessment is important for understanding algal-nutrient relationships and the development of scientifically defensible numeric nutrient criteria. However, multiple methods of periphyton data collection are currently used, and little is known about the comparability of resulting datasets. Literature also suggests other factors besides nutrients (i.e. variable grazing, light, and flow) can confound algal-nutrient relationships. A one-year method comparison study and 31-day algal biomass-nutrient manipulative experiment were conducted in the southern Ozarks of Arkansas. The method comparison study was implemented using two common bioassessment procedures (whole-surface and delimiter-reduced periphyton removal) to assess the potential for combining datasets. During the manipulative experiment, …


Droughtscape, Spring 2016, National Drought Mitigation Center Apr 2016

Droughtscape, Spring 2016, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

Director’s report

First quarter drought summary

First quarter drought impacts

Drought Risk Management Research Center

Kenyan official visits

DrIVER eyes forecasting

Drought scenario exercise

Student projects

Drought tournament

Response and recovery guide

Drought Portal

Network of drought observers

Caribbean “writeshops”

Communications staff grows


Flood-Inundation Maps For A 12.5-Mile Reach Of Big Papillion Creek At Omaha, Nebraska, Kellan R. Strauch, Benjamin J. Dietsch, Kayla J. Anderson Mar 2016

Flood-Inundation Maps For A 12.5-Mile Reach Of Big Papillion Creek At Omaha, Nebraska, Kellan R. Strauch, Benjamin J. Dietsch, Kayla J. Anderson

United States Geological Survey: Water Reports and Publications

Digital flood-inundation maps for a 12.5-mile reach of the Big Papillion Creek from 0.6 mile upstream from the State Street Bridge to the 72nd Street Bridge in Omaha, Nebraska, were created by the United States Geological Survey (USGS) in cooperation with the Papio-Missouri River Natural Resources District. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Big Papillion Creek at Fort Street at Omaha, Nebraska (station 06610732). Near-real-time …


Effects Of Streamflows On Stream-Channel Morphology In The Eastern Niobrara National Scenic River, Nebraska, 1988–2010, Nathaniel J. Schaepe, Jason S. Alexander, Kiernan Folz-Donahue Mar 2016

Effects Of Streamflows On Stream-Channel Morphology In The Eastern Niobrara National Scenic River, Nebraska, 1988–2010, Nathaniel J. Schaepe, Jason S. Alexander, Kiernan Folz-Donahue

United States Geological Survey: Water Reports and Publications

The Niobrara River is an important and valuable economic and ecological resource in northern Nebraska that supports ecotourism, recreational boating, wildlife, fisheries, agriculture, and hydroelectric power. Because of its uniquely rich resources, a 122-kilometer reach of the Niobrara River was designated as a National Scenic River in 1991, which has been jointly managed by the United States Fish and Wildlife Service and National Park Service (NPS). To assess how the remarkable qualities of the National Scenic River may change if consumptive uses of water are increased above current levels, the United States Geological Survey (USGS), in cooperation with the NPS, …


Upscaling Methane Emission Hotspots In Boreal Peatlands, Fabio Cresto Aleina, Benjamin R. K. Runkle, Tim Brucher, Thomas Kleinen, Victor Brovkin Mar 2016

Upscaling Methane Emission Hotspots In Boreal Peatlands, Fabio Cresto Aleina, Benjamin R. K. Runkle, Tim Brucher, Thomas Kleinen, Victor Brovkin

Biological and Agricultural Engineering Faculty Publications and Presentations

Upscaling the properties and effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock–Hollow model, a microtopography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock–Hollow model that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the …


Dissolved Oxygen Monitoring In Kings River And Leatherwood Creek, Eric Cummings, Erin E. Scott, Marty Matlock, Brian E. Haggard Mar 2016

Dissolved Oxygen Monitoring In Kings River And Leatherwood Creek, Eric Cummings, Erin E. Scott, Marty Matlock, Brian E. Haggard

Arkansas Water Resources Center Technical Reports

The Clean Water Act (CWA) establishes the basic structure used to regulate water quality. Under the CWA, States are required to assess water bodies relative to water‐quality standards and designated beneficial uses and then to submit lists of impaired bodies every other year to the US Environmental Protection Agency (USEPA). In 2015, at least 4,800 water bodies were listed as impaired by dissolved oxygen across the US (USEPA, 2015). Aquatic species like fish and macroinvertebrates depend on adequate dissolved oxygen for survival. Low dissolved oxygen can lead to fish kills, reduced aquatic diversity, and nuisance smells from anaerobic conditions – …


Umphlett Qci March 2016, Natalie Umphlett Mar 2016

Umphlett Qci March 2016, Natalie Umphlett

High Plains Regional Climate Center: Staff Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Vegetation Conditions

Early Signs of Spring

Winter Wheat Breaks Dormancy

3-Month Precipitation and Temperature Outlooks

Percent of Average Precipitation: Strong El Niños


Water Balance Monitoring For Two Bioretention Gardens In Omaha, Nebraska, 2011–14, Kellan R. Strauch, David L. Rus, Kent E. Holm Feb 2016

Water Balance Monitoring For Two Bioretention Gardens In Omaha, Nebraska, 2011–14, Kellan R. Strauch, David L. Rus, Kent E. Holm

United States Geological Survey: Water Reports and Publications

Document abstract

Bioretention gardens are used to help mitigate stormwater runoff in urban settings in an attempt to restore the hydrologic response of the developed land to a natural predevelopment response in which more water is infiltrated rather than routed directly to urban drainage networks. To better understand the performance of bioretention gardens in facilitating infiltration of stormwater in eastern Nebraska, the United States Geological Survey (USGS), in cooperation with the Douglas County Environmental Services and the Nebraska Environmental Trust, assessed the water balance of two bioretention gardens located in Omaha, Nebraska by monitoring the amount of stormwater entering and …


Sediment Loads And Transport At Constructed Chutes Along The Missouri River-Upper Hamburg Chute Near Nebraska City, Nebraska, And Kansas Chute Near Peru, Nebraska, Brenda K. Densmore, David L. Rus, Matthew T. Moser, Brent M. Hall, Michael J. Andersen Feb 2016

Sediment Loads And Transport At Constructed Chutes Along The Missouri River-Upper Hamburg Chute Near Nebraska City, Nebraska, And Kansas Chute Near Peru, Nebraska, Brenda K. Densmore, David L. Rus, Matthew T. Moser, Brent M. Hall, Michael J. Andersen

United States Geological Survey: Water Reports and Publications

The United States Geological Survey (USGS), in cooperation with the United States Army Corps of Engineers, monitored suspended sediment within constructed Missouri River chutes during March through October 2012. Chutes were constructed at selected river bends by the US Army Corps of Engineers to help mitigate aquatic habitat lost through the creation and maintenance of the navigation channel on the Missouri River. The restoration and development of chutes is one method for creating shallow-water habitat within the Missouri River to meet requirements established by the amended 2000 Biological Opinion. Understanding geomorphic channel-evolution processes and sediment transport is important for the …


Agriculture Causes Nitrate Fertilization Of Remote Alpine Lakes, Elizabeth J. Hundey, Sam S.D. Russell, Fred Longstaffe, Katrina A. Moser Feb 2016

Agriculture Causes Nitrate Fertilization Of Remote Alpine Lakes, Elizabeth J. Hundey, Sam S.D. Russell, Fred Longstaffe, Katrina A. Moser

Earth Sciences Publications

Humans have altered Earth’s nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use D17O, d18O and d15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic …