+publisher:"Colorado State University" +contributor:("McGrath, Daniel")

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Colorado State University

1. Bonnell, Randall Ray. Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing.

Degree: MS(M.S.), Geosciences, 2020, Colorado State University

URL: http://hdl.handle.net/10217/212050

► Mountain snowpacks act as seasonal reservoirs, providing a critical water resource to ~1.2 billion people globally. Regions with persistent snowpacks (e.g., mountain and polar environments)… (more)

▼ Mountain snowpacks act as seasonal reservoirs, providing a critical water resource to ~1.2 billion people globally. Regions with persistent snowpacks (e.g., mountain and polar environments) are responding quickly to climate change and are warming at faster rates than low-elevation temperate and equatorial regions. Since 1915, snow water equivalent (SWE) in the western U.S. snowpack has declined by 21% and snow covered area is contracting in the Rocky Mountains. Despite the clear importance of this resource and the identification of changes affecting it, no current remote sensing approach can accurately measure SWE at high spactiotemporal resolution. L-band (1-2 GHz) Interferometric Synthetic Aperture Radar (InSAR) is a promising approach for detecting changes in SWE at high spatiotemporal resolution in complex topography, but there are uncertainties regarding its performance, particularly when liquid water content (LWC) is present in the snowpack. LWC exhibits high spatial variability, causing spatially varying radar velocity that introduces significant uncertainty in SWE-retrievals. The objectives of this thesis include: (1) examine the importance of slope, aspect, canopy cover, and air temperature in the development of LWC in a continental seasonal snowpack using 1 GHz ground-penetrating radar (GPR), a proxy for L-band InSAR, and (2) quantify the uncertainty in L-band radar SWE-retrievals in wet-snow. This research was performed at Cameron Pass, a high elevation pass (3120 m) located in north-central Colorado, over the course of multiple survey dates during the melt season of 2019. Transects were chosen which represent a range in slope, aspect and canopy cover. Slope and aspect were simplified using the northness index (NI). Canopy cover was quantified using the leaf area index (LAI). Positive degree days (PDD) was used to represent available melt-energy from air temperature. The spatiotemporal development of LWC was studied along the transects using GPR, probed depths, and snowpit measured density. A subset of this project substituted Terrestrial LiDAR Scans (TLS) for probed depths. Surveys (17 in total, up to 3 surveys per date) were performed on seven dates which began on5 April 2019, where LWC values were ~0 vol. %, and ended on 19 June 2019 where LWC values exceeded 10 vol. %. Point measurements of LWC were observed to change (ΔLWC) by +9 vol. % or -8 vol. % over the course of a single day, but median ΔLWC were ~0 vol. % or slightly negative. LAI was negatively correlated with LWC for 13 out of the 17 surveys. NI was negatively correlated with LWC for 10 out of the 17 surveys. Multi-variable linear regressions to estimate ΔLWC identified several statistically significant variables (p-value < 0.10): LAI, NI, ΔPDD, and NI x ΔPDD. Snow-on Terrestrial LiDAR Scans (TLS) were conducted twice during the melt season, and a snow-off scan was conducted in late summer. Snow-on scans were differenced from the snow-off scan to produce distributed snow depth maps. TLS-derived snow depths compared poorly with probe-derived… Advisors/Committee Members: McGrath, Daniel (advisor), Fassnacht, Steven (committee member), Rasmussen, Kristen (committee member).

Subjects/Keywords: L-band radar; snow; snow water equivalent; liquid water content; ground-penetrating radar; snow melt

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APA (6^th Edition):

Bonnell, R. R. (2020). Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/212050

Chicago Manual of Style (16^th Edition):

Bonnell, Randall Ray. “Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing.” 2020. Masters Thesis, Colorado State University. Accessed April 12, 2021. http://hdl.handle.net/10217/212050.

MLA Handbook (7^th Edition):

Bonnell, Randall Ray. “Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing.” 2020. Web. 12 Apr 2021.

Vancouver:

Bonnell RR. Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10217/212050.

Council of Science Editors:

Bonnell RR. Spatiotemporal variations in liquid water content in a seasonal snowpack: implications for radar remote sensing. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/212050

Colorado State University

2. Cole, Hank M. Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica.

Degree: MS(M.S.), Geosciences, 2020, Colorado State University

URL: http://hdl.handle.net/10217/212036

► Repeating swarms of local icequakes were recorded by broadband seismograpghs deployed near the grounding line of the Ross Ice Shelf, Antarctica from late 2014 to… (more)

▼ Repeating swarms of local icequakes were recorded by broadband seismograpghs deployed near the grounding line of the Ross Ice Shelf, Antarctica from late 2014 to early 2017. Swarms commonly persist for over six hours and contain thousands of events. Most swarms are induced or enhanced by tidal forcing. The number of events and event amplitudes in a swarm is most correlated with the modeled tide range. Some swarms only occur during cold periods of the austral winter. Icequakes are cataloged using a cross-correlation detector after building a template library from clustered STA/LTA picks and epicenters are estimated for high quality events. Events can be classified into four broad categories. The first event type is the most common (>95% of events) and occurs in diurnal swarms at all times of year. This type of event is interpreted to be sourced by propagation of near surface crevasses due to enhanced tensile stress from downward flexure of the ice shelf during falling tide. The second type of event has similar waveforms but occurs at the crest of large spring tides and appears to have an englacial or basal source. The third type of event is likely sourced from within the firn, possibly related to densification. It is also observed at stations in the ice shelf interior, but appears enhanced by tides at stations near the grounding line. The fourth type of event is only observed at a station on the Steershead Ice Rise. These are sweeping harmonic tremors lasting up to 8 s that start at low frequency and then tail upwards into an impulse like signal. This work characterizes these icequake types and their correlation to tidal and environmental forcing. It also details a single station event location scheme that is to used to further interpret events by finding their back azimuth with a polarization analysis and estimate their source-receiver distance with two methods. These observations provide insight into the deformation and brittle fracture at the grounded margins of the Ross Ice Shelf. Advisors/Committee Members: Aster, Richard C. (advisor), McGrath, Daniel (committee member), Cheney, Margaret (committee member), Benz, Harley (committee member).

Subjects/Keywords: grounding line; icequakes; tides; ice shelf; seismology; Antarctica

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APA (6^th Edition):

Cole, H. M. (2020). Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/212036

Chicago Manual of Style (16^th Edition):

Cole, Hank M. “Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica.” 2020. Masters Thesis, Colorado State University. Accessed April 12, 2021. http://hdl.handle.net/10217/212036.

MLA Handbook (7^th Edition):

Cole, Hank M. “Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica.” 2020. Web. 12 Apr 2021.

Vancouver:

Cole HM. Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10217/212036.

Council of Science Editors:

Cole HM. Tidally induced seismicity at the grounded margins of the Ross Ice Shelf, Antarctica. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/212036

Colorado State University

3. Grabowski, Julia. Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado.

Degree: MS(M.S.), Geosciences, 2020, Colorado State University

URL: http://hdl.handle.net/10217/211986

► Sediment waves, a term that describes the fluvial transport of a discrete sediment influx, have long been studied in regard to channel response to infrequent,… (more)

▼ Sediment waves, a term that describes the fluvial transport of a discrete sediment influx, have long been studied in regard to channel response to infrequent, catastrophic events, such as mass movements or dam removal. However, few researchers have studied (1) the potential presence of sediment waves of annual or sub-annual scale in mixed eolian-fluvial geomorphic environments or (2) the role of large wood in sediment wave dispersal. This study addresses both topics through observations of North Sand Creek and East Sand Creek, which flow alongside the active sand dunes of North Sand Hills and East Sand Hills, respectively, in North Park, Colorado. The creeks experience similar seasonal, asynchronous cycles of eolian influx and fluvial transport, although North Sand Creek likely receives a greater volume of eolian sand due to intensive Off-Highway Vehicle (OHV) recreation on the North Sand Hills dunefield. Linear spectral unmixing of Landsat imagery from 1984-2019 is used to determine whether OHV recreation has resulted in vegetation loss, typically associated with elevated eolian flux, on North Sand Hills. Repeat photography and repeat measurement of terrace-like structures are used to determine whether each creek experiences a sediment wave, and repeat measurement of logjam sand wedge volume is used to examine changes in sand storage associated with logjams over time. Results indicate that North Sand Hills hast lost vegetative cover in areas not fenced-off to OHV users at a rate of ~800 m2/year, and that North Sand Creek experiences a highly translative sediment wave that is attenuated by logjams. East Sand Hills, on the other hand, has gained vegetative cover throughout the dunefield, and East Sand Creek does not experience a sediment wave. The sediment wave at North Sand Creek translates rapidly through the area of channel outside of the logjam backwater and translates more slowly through logjam backwater areas—principally through reduction in the length of logjam sand wedges, rather than reduction in depth. Advisors/Committee Members: Wohl, Ellen (advisor), McGrath, Daniel (committee member), Morrison, Ryan (committee member).

Subjects/Keywords: OHV impact; spectral unmixing; sediment wave; eolian-fluvial

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APA (6^th Edition):

Grabowski, J. (2020). Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/211986

Chicago Manual of Style (16^th Edition):

Grabowski, Julia. “Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado.” 2020. Masters Thesis, Colorado State University. Accessed April 12, 2021. http://hdl.handle.net/10217/211986.

MLA Handbook (7^th Edition):

Grabowski, Julia. “Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado.” 2020. Web. 12 Apr 2021.

Vancouver:

Grabowski J. Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10217/211986.

Council of Science Editors:

Grabowski J. Logjam attenuation of annual sediment waves in eolian-fluvial environments, North Park, Colorado. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/211986

Colorado State University

4. Kornse, Zachary. Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains.

Degree: MS(M.S.), Geosciences, 2020, Colorado State University

URL: http://hdl.handle.net/10217/208492

► River restoration has become more of a concern with human influence on natural systems on the rise. Beaver provide a relatively inexpensive and natural opportunity… (more)

▼ River restoration has become more of a concern with human influence on natural systems on the rise. Beaver provide a relatively inexpensive and natural opportunity to restore rivers to a pre-settlement state. Quantitative models can be used to better understand where beaver reintroduction should occur to maximize the odds of a reintroduced beaver population establishing an ideal habitat to thrive in. The Beaver Restoration Assessment Tool (BRAT) is a quantitative model that uses elevation, hydrology, and vegetation inputs to estimate the carrying capacity of beaver. The primary objective of this project is to develop baseline data that can inform river restoration of the Dale Creek watershed on Old Elk Ranch, a northern tributary to the Poudre River in Northern Colorado, although the methods used in this study are broadly applicable to other watersheds. This objective was addressed during two phases of work – the channel and riparian condition assessment during summer 2018 and the assessment of historic and contemporary potential beaver habitat using BRAT and field surveys during summer 2019. Through the utilization of BRAT, survey mapping, and remote sensing, I was further able to determine the best methods for estimating potential beaver population density, as well as the accuracy of the BRAT results relative to the field survey results. Remote sensing provides a unique opportunity to increase the accuracy of BRAT through image classification and analysis. A national vegetation dataset produced by LANDFIRE, with a spatial resolution of 10m, is not as spatially accurate as vegetation datasets derived though supervised classification of NAIP imagery with a 1m spatial resolution. Due to its coarser spatial resolution and being a product of generalized models and field data, LANDFIRE data missed important details in vegetation, such as riparian willows along valley bottoms and variabilities within the floodplain that are crucial for beaver survival. Furthermore, this increase in vegetation accuracy led to increasing the accuracy of BRAT predictions for beaver carrying capacity relative to ground-based mapping of past beaver occupation, allowing for better assessment of where beaver should be reintroduced. Historical BRAT estimates revealed that zero and 1st order channels had the highest carrying capacity of dams historically, accounting for 56% of reaches capable of the highest BRAT classification (15+ dams/km). According to the field survey and historical vs contemporary BRAT estimates, carrying capacity has been greatly reduced post human settlement, primarily in zero and 1st order channel valleys where cattle were introduced. The 2018 condition assessment confirmed that while riparian vegetation was healthiest in higher-order channels, zero and 1st order channels were heavily browsed by cattle, deer, and elk. Based on the distribution of riparian vegetation health, and carrying capacity estimates from BRAT and field surveys, stream restoration would be most effective on 0th and 1st order streams. Advisors/Committee Members: Wohl, Ellen (advisor), McGrath, Daniel (committee member), Morrison, Ryan (committee member).

Subjects/Keywords: beaver restoration assessment tool; image analysis; beaver reintroduction; river restoration; BRAT

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kornse, Z. (2020). Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/208492

Chicago Manual of Style (16^th Edition):

Kornse, Zachary. “Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains.” 2020. Masters Thesis, Colorado State University. Accessed April 12, 2021. http://hdl.handle.net/10217/208492.

MLA Handbook (7^th Edition):

Kornse, Zachary. “Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains.” 2020. Web. 12 Apr 2021.

Vancouver:

Kornse Z. Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10217/208492.

Council of Science Editors:

Kornse Z. Prioritization of beaver (Castor canadensis) reintroduction sites within semi-arid grassland rivers in the Great Plains. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/208492

Colorado State University

5. Siefken, Seth. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/197259

► Rock vanes (also known as stream barbs) and bendway weirs are two types of transverse rock structures used to modify the flow field in river… (more)

▼ Rock vanes (also known as stream barbs) and bendway weirs are two types of transverse rock structures used to modify the flow field in river bends. This study examines the effectiveness of the two types of structures at reducing velocity along the outer bank of river bends to protect the bank from erosion. A numerical model using the commercially available FLOW-3D software was used to evaluate the effect of various rock vane and bendway weir configurations on the flow field through two river bends typical of the Middle Rio Grande. The model was calibrated and validated using data from a previous physical model study of rock vanes. 33 different rock vane configurations were tested in the numerical model to evaluate the effect of altering planform angle, crest slope, projected length, and structure spacing. In addition, 14 different bendway weir configurations were tested to provide a comparison of the relative performance of bendway weirs and rock vanes. The numerical modeling results indicate that rock vanes are more effective at reducing the velocity along the outer bank of a bend than bendway weirs. Modelling showed that the completely submerged crest of bendway weirs allows a substantial amount of flow to pass over the crest, limiting their effectiveness in reducing velocity along the bank. In contrast, rock vanes, with a sloped crest intersecting the waterline at the design flow rate, directed more flow around the tip of the structure rather than over the crest and were much more effective at reducing velocity along the bank. Based on the modeling results, it is recommended that bendway weirs not be installed for the purpose of erosion protection along riverbanks. The reduction in velocity along the bank produced by the various rock vane configurations varied considerably with the geometry of the configuration. Based on the results, the following conclusions are made regarding rock vane geometry: (1) Rock vanes should be installed at a planform angle between 45° and 90° to the river bank. (2) There exists an optimal projected length of rock vane, which lies in the neighborhood of 1/5 to 1/3 of the channel top-width. (3) Rock vanes with a 10% crest slope perform well, although decreasing the crest slope will decrease the velocity along the outer bank and vice versa. (4) Decreasing the spacing of rock vanes decreases the velocity along the outer bank, up to a limit. A design equation was developed to predict the velocity reduction along the bank of a river bend produced by a given configuration of rock vanes, based on the geometry of the rock vanes and the river channel. The equation provided good predictions for the range of configurations tested, having a coefficient of determination r2 = 0.83 and predicting the velocity reduction along the outer bank to within 15 percentage points for all of the tested configurations. Advisors/Committee Members: Ettema, Robert (advisor), Thornton, Christopher (committee member), McGrath, Daniel (committee member).

Subjects/Keywords: bendway weirs; erosion protection; stream barbs; computational fluid dynamics; bank stabilization; rock vanes

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APA (6^th Edition):

Siefken, S. (2019). Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/197259

Chicago Manual of Style (16^th Edition):

Siefken, Seth. “Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.” 2019. Masters Thesis, Colorado State University. Accessed April 12, 2021. http://hdl.handle.net/10217/197259.

MLA Handbook (7^th Edition):

Siefken, Seth. “Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.” 2019. Web. 12 Apr 2021.

Vancouver:

Siefken S. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10217/197259.

Council of Science Editors:

Siefken S. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/197259

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