Physical Sciences and Mathematics Commons^™

The Irrigation Efficiency Trap: Rational Farm-Scale Decisions Can Lead To Poor Hydrologic Outcomes At The Basin Scale, Christina N. Morrisett, Robert W. Van Kirk, London O. Bernier, Andrea L. Holt, Chloe B. Perel, Sarah E. Null

Watershed Sciences Faculty Publications

Agricultural irrigation practices have changed through time as technology has enabled more efficient conveyance and application. In some agricultural regions, irrigation can contribute to incidental aquifer recharge important for groundwater return flows to streams. The Henrys Fork Snake River, Idaho (United States) overlies a portion of the Eastern Snake Plain Aquifer, where irrigated agriculture has occurred for over a century. Using irrigator interviews, aerial and satellite imagery, and statistical streamflow analysis, we document the impact of farm-scale decisions on basin-scale hydrology. Motivated to improve economic efficiency, irrigators began converting from surface to center-pivot sprinkler irrigation in the 1950s, with rapid …

Managing Water Stored For The Environment During Drought, Sarah Null, Jeffrey Mount, Brian Gray, Michael Dettinger, Kristen Dybala, Gokce Sencan, Anna Sturrock, Barton Thompson, Harrison Zeff

Watershed Sciences Faculty Publications

Storing water in reservoirs is important for maintaining freshwater ecosystem health and protecting native species. Stored water also is essential for adapting to the changing climate, especially warming and drought intensification. Yet, reservoir operators often treat environmental objectives as a constraint, rather than as a priority akin to water deliveries for cities and farms. Reservoir management becomes especially challenging during severe droughts when surface water supplies are scarce, and urban and agricultural demands conflict with water supplies needed to maintain healthy waterways and wetlands. In times of drought, most freshwater ecosystems suffer.

This blog post examines 2021 water year actions …

Spatial And Long-Term Temporal Changes In Water Quality Dynamics Of The Tonle Sap Ecosystem, Savoeurn Soum, Peng Bun Ngor, Thomas E. Dilts, Sapana Lohani, Suzanne Kelson, Sarah E. Null, Flavia Tramboni, Zeb S. Hogan, Bunyeth Chan, Sudeep Chandra

Watershed Sciences Faculty Publications

Tonle Sap lake-river floodplain ecosystem (TSE) is one of the world’s most productive freshwater systems. Changes in hydrology, climate, population density, and land use influence water quality in this system. We investigated long term water quality dynamics (22 years) in space and time and identified potential changes in nutrient limitation based on nutrient ratios of inorganic nitrogen and phosphorus. Water quality was assessed at five sites highlighting the dynamics in wet and dry seasons. Predictors of water quality included watershed land use, climate, population, and water level. Most water quality parameters varied across TSE, except pH and nitrate that remained …

Potential For Managed Aquifer Recharge To Enhance Fish Habitat In A Regulated River, Robert W. Van Kirk, Bryce A. Contor, Christina N. Morrisett, Sarah E. Null, Ashly S. Loibman

Watershed Sciences Faculty Publications

Managed aquifer recharge (MAR) is typically used to enhance the agricultural water supply but may also be promising to maintain summer streamflows and temperatures for cold-water fish. An existing aquifer model, water temperature data, and analysis of water administration were used to assess potential benefits of MAR to cold-water fisheries in Idaho’s Snake River. This highly-regulated river supports irrigated agriculture worth US $10 billion and recreational trout fisheries worth $100 million. The assessment focused on the Henry’s Fork Snake River, which receives groundwater from recharge incidental to irrigation and from MAR operations 8 km from the river, addressing (1) the …

Resurgence Of An Apex Marine Predator And The Decline In Prey Body Size, Jan Ohlberger, Daniel E. Schindler, Eric J. Ward, Timothy E. Walsworth, Timothy E. Essington

Watershed Sciences Faculty Publications

In light of recent recoveries of marine mammal populations worldwide and heightened concern about their impacts on marine food webs and global fisheries, it has become increasingly important to understand the potential impacts of large marine mammal predators on prey populations and their life-history traits. In coastal waters of the northeast Pacific Ocean, marine mammals have increased in abundance over the past 40 to 50 y, including fish-eating killer whales that feed primarily on Chinook salmon. Chinook salmon, a species of high cultural and economic value, have exhibited marked declines in average size and age throughout most of their North …

Beavers Alter Stream Macroinvertebrate Communities In Northeastern Utah, Susan E. Washko, Brett B. Roper, Trisha Brooke Atwood

Watershed Sciences Faculty Publications

1. Understanding changes in macroinvertebrate communities is important because they play a large role in stream ecosystem functioning, and they are an important food resource for fish. Beaver‐induced changes to stream morphology could alter macroinvertebrate communities, which in turn could affect food webs and ecosystem function. However, studies investigating the effects of North American beaver activities on macroinvertebrates are rare in the inter‐mountain west, an area with high potential for beaver‐assisted restoration.
2. The aim of this study was to quantify differences in the macroinvertebrate community between unaltered segments of streams and within beaver ponds in north‐eastern Utah, U.S.A. We assessed macroinvertebrate …

Mapping Valley Bottom Confinement At The Network Scale, Gary R. O'Brien, Joseph Michael Wheaton, Kirstie Fryirs, William W. Macfarlane, Gary Brierley, Kelly Whitehead, Jordan T. Gilbert, Carol Volk

Watershed Sciences Faculty Publications

In this article, we demonstrate the application of a continuous confinement metric across entire river networks. Confinement is a useful metric for characterizing and discriminating valley setting. At the reach scale, valley bottom confinement is measured and quantified as the ratio of the length of channel confined on either bank by a confining margin divided by the reach length. The valley bottom is occupied by the contemporary floodplain and/or its channel(s); confining margins can be any landform or feature that makes up the valley bottom margin, such as bedrock hillslopes, terraces, fans, or anthropogenic features such as stopbanks or constructed …

Can The Desiccation Of Great Salt Lake Be Stopped?, Wayne A. Wurtsbaugh, Craig Miller, Sarah E. Null, R. Justin Derose, Peter Wilcock

Watershed Sciences Faculty Publications

Great Salt Lake is a terminal lake, with its watershed in the Wasatch and Uinta Mountains of Utah, Wyoming and Idaho. Like all terminal lakes, the water inflows are balanced only by evaporative loss from its surface—when inflows decrease the lake shrinks until evaporation matches that inflow.

3d Photogrammetry Quantifies Growth And External Erosion Of Individual Coral Colonies And Skeletons, Renata Ferrari, Will F. Figueira, Morgan S. Pratchett, Tatiana Boube, Arne Adam, Tania Kobelkowsky-Vidrio, Steve S. Doo, Trisha Brooke Atwood, Maria Byrne

Watershed Sciences Faculty Publications

Growth and contraction of ecosystem engineers, such as trees, influence ecosystem structure and function. On coral reefs, methods to measure small changes in the structure of microhabitats, driven by growth of coral colonies and contraction of skeletons, are extremely limited. We used 3D reconstructions to quantify changes in the external structure of coral colonies of tabular Acropora spp., the dominant habitat-forming corals in shallow exposed reefs across the Pacific. The volume and surface area of live colonies increased by 21% and 22%, respectively, in 12 months, corresponding to a mean annual linear extension of 5.62 cm yr⁻¹ (±1.81 SE). …

Multi-Scale Environmental Filters And Niche Partitioning Govern The Distributions Of Riparian Vegetation Guilds, Nate Hough-Snee, Brian G. Laub, David M. Merritt, Arin Lexine Long, Lloyd L. Nackley, Brett B. Roper, Joseph Michael Wheaton

Watershed Sciences Faculty Publications

Across landscapes, riparian plant communities assemble under varying levels of disturbance, environmental stress, and resource availability, leading to the development of distinct riparian life-history guilds over evolutionary timescales. Identifying the environmental filters that exert selective pressures on specific riparian vegetation guilds is a critical step in setting baseline expectations for how riparian vegetation may respond to environmental conditions anticipated under future global change scenarios. In this study, we ask: (1) What riparian plant guilds exist across the interior Columbia and upper Missouri River basins? (2) What environmental filters shape riparian guild distributions? (3) How does resource partitioning among guilds influence …

Bear Lake Limnology & Nutrient Limnology, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.

Water Quantity And Quality In The Columbia Basin Trust Region, Janice Brahney

Watershed Sciences Faculty Publications

This report collects the documents generated as part of a two year effort to catalogue the variety of water quality and quantity data that has been collected in the Columbia Basin Trust region of British Columbia. Through the cataloguing effort, a number of important data and knowledge gaps were identified and specific recommendations developed. The available water quantity and climate data was then used in a number of analyses focused on understanding the relationship between changing climate conditions and stream discharges.

One overall finding is that there is a large variety of data collected and held by various different entities. …

Can The Causeway In The Great Salt Lake Be Used To Manage Salinity, Sarah E. Null, Wayne A. Wurtsbaugh, Craig Miller

Watershed Sciences Faculty Publications

No abstract provided.

Automatic Geomorphic Feature Extraction From Lidar In Flat And Engineered Landscapes, Paola Passalacqua, Patrick Belmont, Efi Foufoula-Georgiou

Watershed Sciences Faculty Publications

High-resolution topographic data derived from light detection and ranging (lidar) technology enables detailed geomorphic observations to be made on spatially extensive areas in a way that was previously not possible. Availability of this data provides new opportunities to study the spatial organization of landscapes and channel network features, increase the accuracy of environmental transport models, and inform decisions for targeting conservation practices. However, with the opportunity of increased resolution topographic data come formidable challenges in terms of automatic geomorphic feature extraction, analysis, and interpretation. Low-relief landscapes are particularly challenging because topographic gradients are low, and in many places both the …

Large Shift In Source Of Fine Sediment In The Upper Mississippi River, Patrick Belmont, Karen B. Gran, Shawn P. Schottler, Peter Wilcock, Stephanie S. Day, Carrie Jennings, J. Wesley Lauer, Enrica Viparelli, Jane K. Willenbring, Daniel R. Engstrom, Gary Parker

Watershed Sciences Faculty Publications

Although sediment is a natural constituent of rivers, excess loading to rivers and streams is a leading cause of impairment and biodiversity loss. Remedial actions require identification of the sources and mechanisms of sediment supply. This task is complicated by the scale and complexity of large watersheds as well as changes in climate and land use that alter the drivers of sediment supply. Previous studies in Lake Pepin, a natural lake on the Mississippi River, indicate that sediment supply to the lake has increased 10-fold over the past 150 years.Herein we combine geochemical fingerprinting and a suite of geomorphic change …

Closing The Gap Between Watershed Modeling, Sediment Budgeting, And Stream Restoration, Sean M.C. Smith, Patrick Belmont, Peter Wilcock

Watershed Sciences Faculty Publications

The connection between stream restoration and sediment budgeting runs both ways: stream restoration is proposed as a means to reduce sediment yields, but an accurate understanding of sediment supply is necessary to design an effective project. Recent advances in monitoring technology, geochemical techniques, high-resolution topography data, and numerical modeling provide new opportunities to estimate sediment erosion, transport, and deposition rates; upscale them in a geomorphically relevant fashion; and synthesize sediment dynamics at watershed scales. For practical application at large scale, watershed models used to predict yield often do not resolve lower-order channels, leaving an essential “blind spot” regarding sediment processes. …

Revisiting Scaling Laws In River Basins: New Considerations Across Hillslope And Fluvial Regimes, Chandana Gangodagamage, Patrick Belmont, Efi Foufoula-Georgiou

Watershed Sciences Faculty Publications

Increasing availability of high‐resolution (1 m) topography data and enhanced computational processing power present new opportunities to study landscape organization at a detail not possible before. Here we propose the use of “directed distance from the divide” as the scale parameter (instead of Horton’s stream order or upstream contributing area) for performing detailed probabilistic analysis of landscapes over a broad range of scales. This scale parameter offers several advantages for applications in hydrology, geomorphology, and ecology in that it can be directly related to length‐scale dependent processes, it can be applied seamlessly across the hillslope and fluvial regimes, and it …

Evaluating The Effectiveness Of Grassbed Treatments As Habitat For Juvenile Black Bass In A Drawdown Reservoir, D. R. Ratcliff, Wayne A. Wurtsbaugh, J. Zustak

Watershed Sciences Faculty Publications

Many reservoirs in arid regions experience highly variable water levels caused by seasonal inflow fluctuations and designated outflow requirements. At Shasta Lake, California, managers plant cereal-grain grassbeds on exposed drawdown shorelines to increase juvenile fish habitat, localize productivity, and increase invertebrate fish prey. To determine the efficacy of these plantings, the abundance of juvenile black basses Micropterus spp. (20–55 mm standard length) and the amount of periphyton and macroinvertebrate prey were compared among three treatment types: (1) planted grassbeds of cereal barley Hordeum vulgare; (2) artificial rope grassbeds, which eliminated physical deterioration and nutrient release; and (3) nonplanted control sites …

Lakes And Forests As Determinants Of Downstream Nutrient Concentrations In Small Mountain Watersheds, P. D. Brown, Wayne A. Wurtsbaugh, K. Nydick

Watershed Sciences Faculty Publications

Lakes are dynamic processors of nutrients and may hold an active role in modifying the water chemistry of stream systems. In this study, we examine the influence of lakes and an important terrestrial component—forest cover—on the nutrient levels of stream water in 11 Rocky Mountain (Idaho) watersheds. Water samples were collected from the inflow and outflow of lakes with varying amounts of upstream lakes and forested area during spring runoff and summer base flow. During base flow, mean total nitrogen concentrations at the inflow of final lakes were significantly related to relative upstream lake area, increasing from 34 to 103 …

Fish Nutrient Cycling, Aquatic Respiration, And Terrestrial Insect Nutrient Subsidies To Lakes, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Mehner et al. (2005) reported that fish feeding on terrestrial insects could be important for nutrient budgets and cycling in lakes. They studied bleak (Alburnus alburnus) that fed largely on terrestrial insects, and they suggested that this contributed 2.1% of the lake's nutrient budget and that the subsequent excretion by the fish was equivalent to 11% of epilimnetic dissolved phosphorus concentrations. They concluded that nutrients delivered to lakes via terrestrial insects and recycled by fish would be most important for small lakes because of the large perimeter-to-area ratio between donor and recipient habitats. Fish may have important impacts …

Salinity Controls Phytoplankton Response To Nutrient Enrichment In The Great Salt Lake, Utah, Usa, Amy M. Marcarelli, Wayne A. Wurtsbaugh, O. Griset

Watershed Sciences Faculty Publications

To examine how salinity and nutrient supply interact to control phytoplankton community composition, nutrient limitation, and dinitrogen (N2) fixation rates in the Great Salt Lake (Utah, USA), we conducted a series of bioassay experiments with plankton from both Gilbert Bay, where salinities are near 160 g·L–1, and Farmington Bay, where salinities range from 10 to 90 g·L–1. Six-day nutrient addition bioassay experiments showed that the extant phyto plankton communities in both bays were limited by nitrogen (N). However, in 28- to 30-day factorial bioassay experiments in which both salinities and nutrient supply were manipulated, phosphorus stimulated chlorophyll a as much …

Winter Ecology Of Kokanee: Implications For Salmon Management, G. B. Steinhart, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

We sampled various limnological parameters and measured growth and diet of age-0 kokanee Oncorhynchus nerka (lacustrine sockeye salmon) during two winters in a high-mountain lake of the Sawtooth Valley, Idaho. Although winter has been recognized as an important period for many warmwater fishes and for stream-dwelling salmonids, winter limitations have only recently been studied for coolwater and coldwater species. Ice and snow cover in winter limited light penetration. As a result, chlorophyll-a and zooplankton density were lower in ice-covered periods than during ice-free periods. The weight of stomach contents was often below a maintenance ration, yet the incidence of empty …

Effects Of Epilimnetic Versus Metalimnetic Fertilization On The Phytoplankton And Periphyton Of A Mountain Lake With A Deep Chlorophyll Maxima, Wayne A. Wurtsbaugh, H. P. Gross, Phaedra E. Budy, Chris Luecke

Watershed Sciences Faculty Publications

Nutrients can load directly to either the epilimnion or metalimnion of lakes via either differential inflow depths of tributaries or intentional fertilization of discrete strata. We evaluated the differential effects of epilimnetic versus metalimnetic nutrient loading using 17-m-deep mesocosms that extended into the deep chlorophyll layer of oligotrophic Pettit Lake in the Sawtooth Mountains of Idaho. Addition of nitrogen plus phosphorus stimulated primary production nearly identically (2.4- to 4-fold on different dates) in both treatments, with the production peaks occurring in the strata where nutrients were added. The metalimnetic fertilization, however, resulted in equal or greater stimulation of chlorophyll a …

Salmonine Consumption And Competition For Endemic Prey Fishes In Bear Lake, Utah-Idaho, J. R. Ruzycki, Wayne A. Wurtsbaugh, Chris Luecke

Watershed Sciences Faculty Publications

Two principal sport fish—the indigenous Bonneville cutthroat trout Oncorhynchus clarki utah and the introduced lake trout Salvelinus namaycush—are the dominant piscivores in Bear Lake, a 282-km^2 oligotrophic system. These piscivores rely predominantly on four endemic prey fish species that make up a major portion of the unique Bear Lake fish assemblage. We estimated the annual biomass of pelagic and benthic prey fish by using hydroacoustic and trawling techniques. We also estimated the lakewide abundance of piscivores with a multiple mark–recapture survey and used a bioenergetics model to compare the population-level consumption of prey fish with prey fish production. Prey fish …

Under-Ice Diel Vertical Migrations Of Oncorhynchus Nerka And Their Zooplankton Prey, G. B. Steinhart, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

We used stationary hydroacoustics and measures of environmental conditions (water temperature, dissolved oxygen, light levels, and zooplankton) to determine what factors, foraging or predation risk, influenced diel vertical migrations of Oncorhynchus nerka during winter in three high-mountain lakes. The Sawtooth Valley lakes are deep, oligotrophic, glacial lakes located in central Idaho, U.S.A., and historically contained populations of anadromous O. nerka. In general, low light intensities limited foraging opportunities of O. nerka under ice, especially at night. In Stanley Lake, O. nerka underwent diel vertical migrations to exploit available light to feed. Oncorhynchus nerka occupied shallow water at night, where there …

Ontogenetic Habitat Shifts Of Juvenile Bear Lake Sculpin, J. Ruzycki, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Bear lake sculpin Cottus extensus exhibit ontogenetic habitat shifts during their initial year of life. Distribution and habitat switching was measured with bimonthly bottom-trawl surveys repeated throughout the summer. Patterns of daily growth increments on otoliths were used to measure the history of habitat residence, individual size at the time of the habitat switch, and habitat-specific growth rates. Laboratory experiments and known-age fish confirmed daily increment formation of otoliths. After dispersing during an initial pelagic larval stage, postlarval juveniles settled in both the warm, food-rich littoral zone and the cold, unproductive profundal zone. During summer, initial profundal-zone inhabitants underwent a …

The Role Of Anadromous Sockeye Salmon (Oncorhynchus Nerka) In The Nutrient Loading And Productivity Of The Sawtooth Valley Lakes, Idaho, H. P. Gross, Wayne A. Wurtsbaugh, Chris Luecke

Watershed Sciences Faculty Publications

We constructed a simulation model for Redfish Lake, Idaho, using water budget and nutrient loading measurements, to predict the dependence of lake production on nutrients from the watershed, precipitation, lake fertilization, and marine-derived nutrients from sockeye salmon Oncorhynchus nerka, which historically have reared in the lake. We also used the model to simulate different management scenarios to help restore the endangered Snake River sockeye salmon. The model and other empirical evidence indicated that even before hydropower dams were present in the migration corridor, marine-derived nutrients were not of major importance to lake production, contributing only about 3% of the annual …

Adding Nutrients To Enhance The Growth Of Endangered Sockeye Salmon: Trophic Transfer In An Oligotrophic Lake, Phaedra E. Budy, Chris Luecke, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

Snake River sockeye salmon Oncorhynchus nerka, listed under U.S. law as endangered in 1991 in response to a decline in anadromous adult numbers, spend their first 1–2 years in Redfish Lake, Idaho, before migrating to the sea. To determine how nutrient enhancement might influence phytoplankton, zooplankton, and fish production, we performed fertilization experiments in large enclosures in this oligotrophic lake using juvenile kokanee (lacustrine O. nerka) as analogues for endangered sockeye salmon. Fertilization of the metalimnion substantially increased chlorophyll a (150%), phytoplankton biovolume (75%), primary productivity (250%), and zooplankton biomass (200%), and moderately increased fish growth (12%) over our control …

Fertilization Of An Oligotrophic Lake With A Deep Chlorophyll Maximum: Predicting The Effect On Primary Productivity, H. P. Gross, Wayne A. Wurtsbaugh, Phaedra E. Budy, Chris Luecke

Watershed Sciences Faculty Publications

We investigated how epilimnetic fertilization would affect chlorophyll levels and light penetration of oligotrophic sockeye salmon (Oncorhynchus nerka) lakes and how the resulting self-shading would affect primary production of the prominent deep chlorophyll maxima (DCM) of the lakes. Epilimnetic nutrient additions to large mesocosms (330 m3) in Redfish Lake, Idaho, increased levels of primary productivity and chlorophyll a but decreased Secchi depths and light available in the metalimnion and hypolimnion. Redfish Lake and other Sawtooth Valley (Idaho) lakes had DCM in which the mean chlorophyll a peaks were 240-1000% of mean epilimnetic chlorophyll a concentrations. The DCM existed at low …

Hydroacoustic Assessment Of Abundance And Diel Distribution Of Sockeye Salmon And Kokanee In The Sawtooth Valley Lakes, Idaho, D. Beauchamp, Chris Luecke, Wayne A. Wurtsbaugh, H. G. Gross, Phaedra E. Budy, S. Spaulding, R. Dilenger, C. P. Gubala

Watershed Sciences Faculty Publications

We used dual-beam hydroacoustics and echo integration techniques, combined with midwater trawling and gillnetting, to assess the abundance and distribution of the endangered Snake River juvenile sockeye salmon and resident kokanee (both Oncorhynchus nerka) in Sawtooth Valley lakes of Idaho during September 1991 and 1992. Abundance of O. nerka varied among the four lakes containing this species (12,500–257,000) and varied between years in Redfish Lake (86,400 in 1994 and 241,000 in 1992) and Alturas Lake (230,000 in 1991 and 257,000 in 1992). In Alturas Lake, where piscivore densities were high and zooplankton densities were low, small acoustic targets (≤18 cm …