Physical Sciences and Mathematics Commons^™

Effects Of Changing Climate Extremes And Vegetation Phenology On Wildlife Associated With Grasslands In The Southwestern United States, Tyler G. Creech, Matthew A. Williamson, Steven E. Sesnie, Esther S. Rubin, Daniel R. Cayan, Erica Fleishman

Human-Environment Systems Research Center Faculty Publications and Presentations

Assessments of the potential responses of animal species to climate change often rely on correlations between long-term average temperature or precipitation and species' occurrence or abundance. Such assessments do not account for the potential predictive capacity of either climate extremes and variability or the indirect effects of climate as mediated by plant phenology. By contrast, we projected responses of wildlife in desert grasslands of the southwestern United States to future climate means, extremes, and variability and changes in the timing and magnitude of primary productivity. We used historical climate data and remotely sensed phenology metrics to develop predictive models of …

Predictions And Drivers Of Sub-Reach-Scale Annual Streamflow Permanence For The Upper Missouri River Basin: 1989–2018, Kendra E. Kaiser

Geosciences Faculty Publications and Presentations

The presence of year-round surface water in streams (i.e., streamflow permanence) is an important factor for identifying aquatic habitat availability, determining the regulatory status of streams, managing land use change, allocating water resources, and designing scientific studies. However, accurate, high resolution, and dynamic prediction of streamflow permanence that accounts for year-to-year variability at a regional extent is a major gap in modeling capability. Herein, we expand and adapt the U.S. Geological Survey (USGS) PRObability of Streamflow PERmanence (PROSPER) model from its original implementation in the Pacific Northwest (PROSPER_PNW) to the upper Missouri River basin (PROSPER_UM), a …

From Soils To Streams: Connecting Terrestrial Carbon Transformation, Chemical Weathering, And Solute Export Across Hydrological Regimes, Alejandro Flores, Katie Murenbeeld

Geosciences Faculty Publications and Presentations

Soil biota generates carbon that exports vertically to the atmosphere (CO₂) and transports laterally to streams and rivers (dissolved organic and inorganic carbon, DOC and DIC). These processes, together with chemical weathering, vary with flow paths across hydrological regimes; yet an integrated understanding of these interactive processes is still lacking. Here we ask: How and to what extent do subsurface carbon transformation, chemical weathering, and solute export differ across hydrological and subsurface structure regimes? We address this question using a hillslope reactive transport model calibrated using soil CO₂ and water chemistry data from Fitch, a temperate forest …

Pervasive Changes In Stream Intermittency Across The United States, Kendra E. Kaiser

Geosciences Faculty Publications and Presentations

Non-perennial streams are widespread, critical to ecosystems and society, and the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based on long-term averages, generally using annually aggregated data to characterize a highly variable process. As a result, it is not well understood if, how, or why the hydrology of non-perennial streams is changing. Here, we investigate trends and drivers of three intermittency signatures that describe the duration, timing, and dry-down period of stream intermittency across the continental United States (CONUS). Half of gages exhibited a significant trend through time in at least one of the …

Another Dangerous Fire Season Is Looming In The Western U.S., And The Drought-Stricken Region Is Headed For A Water Crisis, Mojtaba Sadegh, Amir Aghakouchak, John Abatzoglou

Civil Engineering Faculty Publications and Presentations

Just about every indicator of drought is flashing red across the western U.S. after a dry winter and warm early spring. The snowpack is at less than half of normal in much of the region. Reservoirs are being drawn down, river levels are dropping and soils are drying out.

It’s only May, and states are already considering water use restrictions to make the supply last longer. California’s governor declared a drought emergency in 41 of 58 counties. In Utah, irrigation water providers are increasing fines for overuse. Some Idaho ranchers are talking about selling off livestock because rivers and reservoirs …

Pooling Data Improves Multimodel Idf Estimates Over Median-Based Idf Estimates: Analysis Over The Susquehanna And Florida, Abhishekh Kumar Srivastava, Richard Grotjahn, Paul Aaron Ullrich, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Traditional multimodel methods for estimating future changes in precipitation intensity, duration, and frequency (IDF) curves rely on mean or median of models’ IDF estimates. Such multimodel estimates are impaired by large estimation uncertainty, shadowing their efficacy in planning efforts. Here, assuming that each climate model is one representation of the underlying data generating process, i.e., the Earth system, we propose a novel extension of current methods through pooling model data: (i) evaluate performance of climate models in simulating the spatial and temporal variability of the observed annual maximum precipitation (AMP), (ii) bias-correct and pool historical and future AMP data of …

The Year The West Was Burning: How The 2020 Wildfire Season Got So Extreme, Mojtaba Sadegh, Ata Akbari Asanjan, Mohammad Reza Alizadeh

Civil Engineering Faculty Publications and Presentations

More than 4 million acres of California went up in flames in 2020 – about 4% of the state’s land area and more than double its previous wildfire record. Five of the state’s six largest fires on record were burning this year.

In Colorado, the Pine Gulch fire broke the record for that state’s largest wildfire, only to be surpassed by two larger blazes, the Cameron Peak and East Troublesome fires.

Oregon saw one of the most destructive fire seasons in its recorded history, with more than 4,000 homes destroyed.

What caused the 2020 fire season to become so extreme?

Including Variability Across Climate Change Projections In Assessing Impacts On Water Resources In An Intensively Managed Landscape, Bangshuai Han, Shawn G. Benner, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

In intensively managed watersheds, water scarcity is a product of interactions between complex biophysical processes and human activities. Understanding how intensively managed watersheds respond to climate change requires modeling these coupled processes. One challenge in assessing the response of these watersheds to climate change lies in adequately capturing the trends and variability of future climates. Here we combine a stochastic weather generator together with future projections of climate change to efficiently create a large ensemble of daily weather for three climate scenarios, reflecting recent past and two future climate scenarios. With a previously developed model that captures rainfall-runoff processes and …

Climate Change And Curtailment: Evaluating Water Management Practices In The Context Of Changing Runoff Regimes In A Snowmelt-Dominated Basin, Amy L. Steimke, Bangshuai Han, Jodi S. Brandt, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and their impacts a key variable governing administration of water resources in the region in an integrated way. This snowmelt-dominated, mountainous watershed supplies water to a semi-arid, agriculturally intensive, but rapidly urbanizing, region. Using the Envision integrated modeling framework, we created a hydrological model to simulate hydrological response to the year 2100 using six alternative future climate trajectories. …

Ice Core Records Of West Greenland Melt And Climate Forcing, H.P. Marshall, T. Meehan

CGISS Publications and Presentations

Remote sensing observations and climate models indicate that the Greenland Ice Sheet (GrIS) has been losing mass since the late 1990s, mostly due to enhanced surface melting from rising summer temperatures. However, in situ observational records of GrIS melt rates over recent decades are rare. Here we develop a record of frozen meltwater in the west GrIS percolation zone preserved in seven firn cores. Quantifying ice layer distribution as a melt feature percentage (MFP), we find significant increases in MFP in the southernmost five cores over the past 50 years to unprecedented modern levels (since 1550 CE). Annual to decadal …

Climate Change, Cattle, And The Challenge Of Sustainability In A Telecoupled System In Africa, Tara S. Easter, Alexander K. Killion, Neil H. Carter

Ecology, Evolution, and Behavior

Information, energy, and materials are flowing over greater distances than in the past, changing the structure and feedbacks within and across coupled human and natural systems worldwide. The telecoupling framework was recently developed to understand the feedbacks and multidirectional flows characterizing social and environmental interactions between distant systems. We extend the application of the telecoupling framework to illustrate how flows in beef affect and are affected by social-ecological processes occurring between distant systems in Africa, and how those dynamics will likely change over the next few decades because of climate-induced shifts in a major bovine disease, trypanosomosis. The disease is …

Vegetative And Climatic Controls On Holocene Wildfire And Erosion Recorded In Alluvial Fans Of The Middle Fork Salmon River, Idaho, Kerry Riley, Jennifer Pierce, Grant A. Meyer

Geosciences Faculty Publications and Presentations

The Middle Fork Salmon River watershed spans high-elevation mixed-conifer forests to lower-elevation shrub-steppe. In recent decades, runoff from severely burned hillslopes has generated large debris flows in steep tributary drainages. These flows incised alluvial fans along the mainstem river, where charcoal-rich debris-flow and sheetflood deposits preserve a record of latest Pleistocene to Holocene fires and geomorphic response. Through deposit sedimentology and ¹⁴C dating of charcoal, we evaluate the processes and timing of fire-related sedimentation and the role of climate and vegetation change. Fire-related deposits compose ~66% of the total measured fan deposit thickness in more densely forested upper basins …

Sediment And Nutrient Delivery From Thermokarst Features In The Foothills Of The North Slope, Alaska: Potential Impacts On Headwater Stream Ecosystems, W. B. Bowden, M. N. Gooseff, A. Balser, A. Green, B. J. Peterson, John H. Bradford

CGISS Publications and Presentations

Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km² area in and around the Toolik Lake Natural Research Area (TLNRA) revealed at least 34 thermokarst features, two thirds of which were new since ~1980 when a high resolution aerial survey of the area was done. Most of these thermokarst features were associated with headwater streams or lakes. We have measured significantly increased sediment and nutrient loading from thermokarst features to streams in two well-studied locations …

Influence Of Morphology And Permafrost Dynamics On Hyporheic Exchange In Arctic Headwater Streams Under Warming Climate Conditions, Jay P. Zarnetske, Michael N. Gooseff, W. Breck Bowden, Morgan J. Greenwald, Troy R. Brosten, John H. Bradford, James P. Mcnamara

CGISS Publications and Presentations

We investigated surface-subsurface (hyporheic) exchange in two morphologically distinct arctic headwater streams experiencing warming (thawing) sub-channel conditions. Empirically parameterized and calibrated groundwater flow models were used to assess the influence of sub-channel thaw on hyporheic exchange. Average thaw depths were at least two-fold greater under the higher-energy, alluvial stream than under the lowenergy, peat-lined stream. Alluvial hyporheic exchange had shorter residence times and longer flowpaths that occurred across greater portions of the thawed sediments. For both reaches, the morphologic (longitudinal bed topography) and hydraulic conditions (surface and groundwater flow properties) set the potential for hyporheic flow. Simulations of deeper thaw, …