Hydrology Commons^™

Geochemical Dynamics And Nitrous Oxide Release From The Hyporheic Zone Of Streams, Annika Marie Quick

Boise State University Theses and Dissertations

The hyporheic zones of streams and rivers, consisting of the sediments beneath and immediately adjacent to the stream channel, are an important site of geochemical processing. Due to the difficulty of measuring these geochemical processes in the hyporheic zone in situ with meaningful spatial and temporal resolution, we conducted multiple column and large-scale flume experiments to model 1D and 2D hyporheic flow paths and observed important geochemical reactions, including the production and consumption of nitrous oxide (N₂O). N₂O is a significant greenhouse gas, but the controls on its emissions from streams are poorly constrained. We describe …

Mapping Soil Organic Carbon (Soc) In A Semi-Arid Mountainous Watershed Using Variables From Hyperspectral, Lidar And Traditional Datasets, Ryan Matthew Will

Boise State University Theses and Dissertations

Quantifying soil organic carbon (SOC) in complex terrain is challenging due to its high spatial variability. Generally, limited discrete observations of SOC data are used to develop spatially distributed maps of SOC by developing quantitative relationships between SOC and available spatially distributed variables. In many ecosystems, remotely sensed information on aboveground vegetation can be used to predict belowground carbon stocks. In this research, we developed maps of SOC across a semi-arid watershed based on discrete field observations and modeling using a suite of variables inclusive of hyperspectral and lidar datasets; these observations provide insights into the controls on soil carbon …

Trace Chemical Evaluation Of Cloud Seeding In The Payette Basin, James Mitchell Fisher

Boise State University Theses and Dissertations

Glaciogenic cloud seeding increases the fraction of super cooled liquid water precipitating from a given storm. Orographic clouds tend to be inefficient at higher cloud temperatures due to the lack of active natural ice nuclei. Adding artificial ice nuclei active at temperatures greater than -12^oC (where most natural ice nuclei are inactive) may result in an increase in snow precipitation, especially in orographic clouds. Silver iodide (AgI) is typically the artificial nucleating agent for winter orographic cloud seeding. Recent estimates suggest the addition of AgI to orographic storm clouds enhance precipitation by 3 - 15%. However, the National …

Exploring The Impact Of Climate And Land Cover Change On Regional Hydrology In A Snowmelt-Dominated Watershed: The Upper Boise River Basin, Idaho, Amy Steimke

Boise State University Theses and Dissertations

Seasonally snow-dominated, mountainous watersheds supply water to many human populations globally. However, the timing and magnitude of water delivery from these watersheds has already and will continue to change as climate is altered. Associated changes in watershed vegetation cover further affect the runoff responses of watersheds, from altering evapotranspiration rates to changing surface energy fluxes, and there exists a need to incorporate land cover change in hydrologic modeling studies. However, few land cover projections exist at the scale needed for watershed studies, and current models may be unable to simulate key interactions that occur between land cover and hydrologic processes. …

Using Mountain Snowpack To Predict Summer Water Availability In Semiarid Mountain Watersheds, Rebecca Dawn Garst

Boise State University Theses and Dissertations

In the mountainous landscapes of the western United States, water resources are dominated by snowpack. As temperatures rise in spring and summer, the melting snow produces an increase in river flow levels. Reservoirs are used during this increase to retain surplus water, which is released to supplement growing season water supply once the peak flows decrease to below water demands. Once there is no longer surplus natural flow of water, the water accounting changes – referred to as the day of allocation (DOA), and water previously retained within the reservoir is used to supplement the lower flow levels. The amount …

Using Stable Isotope Hydrology To Partition Evapotranspiration In The Sagebrush Steppe, Kellie Jo Rey

Boise State University Theses and Dissertations

Evapotranspiration (ET) is a major part of ecosystem water loss. This thesis aims to develop methods that partition soil water loss into evaporation (E) and transpiration (T). Water balance methods may improve with relative contributions of evaporation (E) and transpiration (T). Isotopic fractionation distinguishes soil water loss due to evaporation from that of plant uptake. This provides a means to assess E and T in retrospect rather than only measuring ET fluxes. To measure the isotopic composition of soil water, we used a liquid-vapor equilibration method following Wassenaar (2008). Experimental trials of different soil amounts and equilibration times were performed …

Riparian Zone Evapotranspiration Using Streamflow Diel Signals, Ethan Thomas Geisler

Boise State University Theses and Dissertations

Riparian zones are crucial regions of semi-arid and arid watersheds. In the summer, riparian zones provide an important habitat for the watershed since they have sufficient water supply throughout the year. However, little is known about the impact of riparian zone evapotranspiration (ET) at a watershed scale. The use of streamflow diel signals can provide a more thorough understanding of riparian zone processes, particularly evapotranspiration. The streamflow diel signals were analyzed for Dry Creek Experimental Watershed (DCEW), for the summer of 2014, to determine riparian evapotranspiration. The riparian zone evapotranspiration was compared to a spatially distributed evapotranspiration model to determine …

Impacts Of Changing Snowmelt Timing On Non-Irrigated Crop Yield, Erin Murray

Boise State University Theses and Dissertations

As climate changes, the final date of spring snowmelt is projected to occur earlier in the year within the western United States. This earlier snowmelt timing may impact crop yield in snow-dominated watersheds by changing the timing of water delivery to agricultural fields. There is considerable uncertainty about how agricultural impacts of snowmelt timing may vary by region, crop type, and practices like irrigation vs. dryland farming. We utilize parametric regression techniques to isolate the magnitude of impact snowmelt timing has had on historical crop yield independently of climate and physiographic variables that also impact yield. To do this, we …

Stable Isotopes Reveal A Disconnect Between Biotic And Abiotic Hydrological Processes In A Seasonally-Dry, Semi-Arid Watershed, Ryan James Mccutcheon

Boise State University Theses and Dissertations

Until recently, it had been thought that humid catchment woody plants transpired primarily mobile soil water that would otherwise flow to streams or recharge groundwater. However, several recent studies have suggested that trees in seasonally-dry humid catchments use primarily tightly-bound, immobile soil water that does not fully mix with new precipitation or participate in translatory flow. McDonnell (2014) called this existence of two, hydrologically-distinct, water pools “the two water worlds hypothesis.” This ecohydrological behavior has important implications for understanding a wide range of catchment processes, including the spatial and temporal variability of evapotranspiration and nutrient cycling, and our abilities to …

Estimating Unsaturated Flow Properties In Coarse Conglomeratic Sediment, Michael James Thoma Jr.

Boise State University Theses and Dissertations

In this dissertation, I address the lack of knowledge of unsaturated flow in coarse, conglomeratic sediment by determining if functional θ-ψ-K relationships, specifically van Genuchten-Mualem (VGM) relationships, developed to predict unsaturated flow in relatively fine-grained sediment can be directly applied to coarse, conglomeratic sediment. In the summer of 2011, a field-scale infiltration test was conducted at the Boise Hydrogeophysical Research Site to determine if functional ψ-θ-K relationships could be applied to infiltration in coarse, conglomeratic sediment, and to estimate parameter values for the VGM relationships. Vertically and laterally distributed ψ(t) and θ( …

Assessing Local Snow Variability Using A Network Of Ultrasonic Snow Depth Sensors, Erik Thorsten Boe

Boise State University Theses and Dissertations

During the 2009-2010 winter season, 21 inexpensive ultrasonic snow depth (USD) sensors were constructed and installed, in addition to two standard Judd USD sensors, at Treeline and Lower Deer Point sites located within the snow dominated Dry Creek Experimental Watershed, near Boise, Idaho. Six USD sensors, including a single Judd Communications USD sensor, were installed at the Treeline site along a northeast to southwest transect of the small 0.02 km² catchment. Seventeen USD sensors, including a single Judd Communications USD sensor, were installed at Lower Deer Point in a randomized stratified pattern with respect to aspect and vegetation to …

Synthesizing Measurement, Modeling And Remote Sensing Techniques To Study Spatiotemporal Variability Of Seasonal Snow, Andrew R. Hedrick

Boise State University Theses and Dissertations

Mountain snowpacks vary drastically over length scales as small as 1—2 meters in complex terrain and require high resolution measurements to accurately quantify the spatial distribution of snow. This thesis explores this spatial distribution using remote sensing, modeling and ground-based observations. Snow depth estimates from airborne LiDAR at 5 m resolution over 750 km² was compared to in situ observations and results from physically-based snow and wind redistribution models, and a new low cost method for continuous depth measurements at the slope scale was developed.

Repeated airborne Light Detection And Ranging (LiDAR) surveys are capable of recording snow depth …

Transfer Of Snow Information Across The Macro-To-Hillslope-Scale Gap Using A Physiographic Downscaling Approach: Implications For Hydrologic Modeling In Semiarid, Seasonally Snow-Dominated Watersheds, Reggie D. Walters

Boise State University Theses and Dissertations

Snow and ice are substantial components of the global energy balance and hydrologic cycle. Seasonal snow covers an area of 47 million km² at its average maximum extent, 98% of which occurs across the Northern Hemisphere. The earth’s radiation budget is largely controlled by the fraction of absorbed solar energy, a parameter that is dependent upon snow surface albedo. Mountain snowpacks act as natural reservoirs, storing large quantities of water throughout the winter until eventual release during the melting phase. Accurate characterization of snow-covered area (SCA) and snow water equivalent (SWE) in such terrain could substantially improve the estimation …

The Hydrologic Significance Of Lateral Water Flow Through Snow, David Parker Eiriksson

Boise State University Theses and Dissertations

Understanding the mechanisms by which catchments route vertical water inputs laterally to stream channels is central to the development of accurate predictive models of watershed processes. It is commonly assumed that lateral redistribution occurs as overland or subsurface flow. Lateral flow can also occur within the snowpack during rain-on-snow (ROS) events or spring melt, sometimes resulting in surface expressions commonly called "runnels." This thesis examines lateral flow through snow and the role of the snowpack as a rapid down-slope water delivery mechanism, with the goal of determining if lateral flow through snow is an important control on streamflow generation and …

Spatial Distribution And Evolution Of A Seasonal Snowpack In Complex Terrain: An Evaluation Of The Snodas Modeling Product, Brian Trail Anderson

Boise State University Theses and Dissertations

Hydrologists and water managers have been attempting to accurately estimate watershed scale snow water equivalent (SWE) for over a century. Extensive monitoring networks, remote sensing technology, and sophisticated modeling approaches have greatly improved these estimates; however, water inputs from snow in mountainous areas are still subject to considerable uncertainty due to SWE spatial variability. In an attempt to improve the understanding of physical processes and controls influencing SWE spatial variability, a field campaign to measure the spatial and temporal distribution of SWE within the Dry Creek Experimental Watershed (DCEW) was conducted during 2009 and 2010. These measurements are compared to …

Characterization And Quantification Of Ground Heat Flux For Late Season Shallow Snow, Aurele Lamontagne

Boise State University Theses and Dissertations

Increasing populations, rapid land use changes, and climate change in mountainous areas have stressed water resources and reduced available water from snowpacks. In anticipation of warmer temperatures, receding snowlines, and increasing water demands, water managers will need detailed snowmelt energy and water balance information from the margin as transitional snow replaces deeper snowpacks. Patchy shallow snow, found at transitional snow elevations, has a distinct energy balance that includes local advection and short wave radiation penetration of snow less than 10 cm deep. Solar penetration to the soil surface provides a heat source that can be absorbed by the soil and …