Master of Science in Water Resources Science Theses

Persistent link for this collectionhttps://hdl.handle.net/11299/227778

This collection contains some of the theses produced by master's degree students in the interdisciplinary Master of Science in Water Resources Science graduate program operated in partnership with the University of Minnesota Twin Cities. Additional theses can be found in the University of Minnesota Twin Cities Dissertations and Theses collection.

Search within Master of Science in Water Resources Science Theses

Browse

Now showing 1 - 11 of 11

Habitat Quality in the Floodplain Following a Channel Reconfiguration Project: Stewart River, MN
(2021-02) Scott, Larissa
Low flows and elevated temperatures threaten many cold-water habitats. Restoration work is commonly implemented to improve a variety of habitat degradations like elevated temperatures and lack of deep pool habitat. However, the influence of restoration work on groundwater storage and connectivity in systems with low human impacts is not well understood, especially restoration projects that involve the installation of off-channel ponds. This study looks at the connectivity and habitat quality of seven floodplain ponds with very different morphology and connectivity with the channel. The ponds were constructed as part of a large channel reconfiguration project to decrease width-to depth ratios, and improve/create coldwater fish habitat in the Stewart River, a trout stream near Two Harbors, Minnesota. During May-September of 2016 and 2017 (one year and two years following the realignment work), I studied the constructed ponds influence on water storage and water temperatures by installing water level and temperature sensors in the ponds, in shallow groundwater wells, and in the main channel. I also measured dissolved oxygen in the channel and ponds and surveyed the locations of thermal refuges between 2016 and 2018. Only one of seven floodplain ponds had suitable low-flow habitat for coldwater fish. This pond (P761) was directly connected to the channel at all flows. Three of six ponds in which temperature was measured throughout the summer were warmer than the channel, and six of seven ponds exhibited low dissolved oxygen levels (≤ 7 mg/L) in summer. Habitat quality in ponds, as measured by temperature and dissolved oxygen, was related to shading, pond morphology, and connectivity with the channel. Sunny locations displayed warmer water temperatures than shaded locations (p = 0.0001). Dissolved oxygen levels increased with pond surface area and connectivity with the channel. This study illustrates that pond geometry, connectivity with the channel, and canopy cover primarily drive temperature and dissolved oxygen levels in constructed ponds. Water elevations in five ponds and several channel locations showed that water levels in the channel peaked earlier and receded slightly quicker than ponds following precipitation events. It took about a day for the channel to reach its peak water elevation following summer precipitation events and two days for constructed ponds to peak. Pond water elevations receded to half their elevation ~3-6 days slower than the channel, but not gradually enough to augment low flows long term. During storm events, channel water elevations peaked earlier and were higher than nearby pond water elevations making the upper part of the realignment behave like a losing reach. Overall, the Stewart River reconfiguration project did not generate substantial long-term water storage or lasting high-quality floodplain fish habitats. This study illustrates the challenges and risks of channel re-meandering in flashy, relatively healthy river systems.
Understory Transpiration Rates Following Stand Density Reduction in a Coast Redwood Forest
(2020-08) Hammerschmidt, Shelby
In forests where the overstory canopy has been disturbed, evapotranspiration (ET) by the understory may be the main flux of water back to the atmosphere. The ability to take field measurements of water use by understory plants, therefore, is vital for a complete ecosystem water budget. However, little research has been apportioned to directly measuring understory water use, and the technology to do so is thus limited. Portable ET chambers have been used to measure ET rates in agricultural fields, grasslands, and deserts, but not in a forest understory. Thus, a portable rapid chamber which can be easily deployed and collect quick ET measurements of single plants was developed for measuring understory plant water use in logged watersheds in coastal California. Mean understory ET rate was highest in the watershed with the lowest residual basal area ( = 87  56 mm/day) and lowest in the control watershed ( = 31  19 mm/day). Multiple regression modeling indicates that the difference in ET rate between watersheds is caused by freed soil water as a result of overstory tree removal. These results imply that understory water use is likely significant in harvested watersheds, and should be quantified at the landscape scale.
Stratigraphic Correlation and Geochronology of Varved Sediments from Lake Malawi, East Africa
(2001-01-29) Barry, Sylvia Lee
Five nine-m long piston cores and 16 multi-cores less than 60 cm long were obtained for a paleoclimate study from Lake Malawi in East Africa, and have provided the first high-resolution geochronology of varved lake sediments from the southern tropics. The establishment of this 22,000-year sedimentation chronology is essential to the construction of a paleoenvironmental history of Lake Malawi, and so that results obtained from subsequent work on sediment chemistry and diatom content of the cores can be expressed on a well-dated basis. The cores were stratigraphically correlated using volcanic ash beds and magnetic susceptibility measurements, and were dated using lead-210 assay, radiocarbon and varve counts. Interpretation of the stratigraphy and geochemistry suggests that Lake Malawi experienced a lowstand during the Last Glacial Maximum (LGM); however, the presence or absence of varves does not seem to be dependent on lake level. Thickness was measured on varves spanning the last 600 years on one of the cores. Spectral analysis of a time series constructed from these measurements exhibit periodicities in the 3-4 yr, 8 yr and 17 yr range, suggesting an El Nino/Southern Oscillation (ENSO) type signal or some as yet unknown forcing mechanism. Trace element from discrete ash layers within the cores provided a unique geochemical fingerprint for each tephra, which is useful for correlation of other cores in the absence of varves or other stratigraphic markers.
Groundwater Flow Modeling and the Delineation of Wellhead Protection Areas, Cass County, Minnesota
(2002-09) Bertsch, Benjamin Robert
Minnesota Rules define wellhead protection as "a method of preventing well contamination by effectively managing potential contaminant sources in all or a portion of a well's recharge area". They further state that this recharge area, or wellhead protection area is the "surface and subsurface area surrounding a well or well field that supplies a public water system, through which contaminants are likely to move toward and reach the well or well field". 1986 Amendments to the Safe Drinking Water Act mandated States to prepare a Wellhead Protection Program and submit it to the Environmental Protection Agency by 1989. Whereas the EPA allows flexibility in each State's specific Wellhead Protection Plan Program, the programs must address certain criteria. Through legislation, the Minnesota Department of Health has established guidance for communities to follow in developing their Wellhead Protection Programs. This guidance provides for ample involvement at the community level, but relies on scientific investigation for the delineation of the wellhead protection area. Using four communities in Cass County, Minnesota, this study demonstrates the value of published data and local expertise in creating groundwater flow models for use in delineating wellhead protection areas. The guidelines established by the Minnesota Department of Health for delineation of wellhead protection areas requires that five criteria must be addressed. These criteria are: Time of travel: The time of travel must be at least ten years. Flow boundaries: The location and influence of flow boundaries must be identified using existing information. Daily volume of water pumped: The daily volume of water pumped must be calculated for each well in the public water supply system. Groundwater flow field: The groundwater flow field must be identified for the aquifer used by the public water supply. Aquifer transmissivity: The aquifer transmissivity must be calculated. Using MODFLOW, a modular three-dimensional finite-difference groundwater flow model, steady state flow models of the four areas were created and calibrated. MODPATH, a particle tracking post-processing package for MODFLOW, was used to determine the well capture zone. Landform assemblages provided a framework for data entry into the model. Minnesota Department of Health Water Well Records supplied stratigraphic information. USGS 1:24,000 quadrangle topographic maps provided calibration data. Assistance from State and County employees and local well drillers addressed specific local geologic and hydrogeologic variables. The resultant flow models and particle traces established wellhead protection areas for the communities studied. These wellhead protection area delineation's address State guidelines and were accomplished in an economic, efficient manner.
Holocene Climate and Environmental Change from White Owl Lake Sediments, White River Plateau, Colorado
(2009-06) Kramer, Marian Esther
This Masters project investigates the Holocene lacustrine sedimentary record of White Owl Lake (3,270 m), a small alpine lake located on the White River Plateau in west-central Colorado. Past changes in the watershed and within the lake are reflected in the sedimentary geochemical record; timing is constrained by radiocarbon ages. The combined data have been used to develop an age model and compare paleoclimatic and paleoenvironmental interpretations with findings from other nearby studies. Processes reflected in the geochemical record include development of terrestrial vegetation, lake basin evolution, changes in primary productivity, preservation of carbonates, changes in hydrology, and shifts in silicate provenance. Seismic-reflection profiles were used to select a site for sediment coring and to create a bathymetric map of White Owl Lake. Lithological changes in the White Owl Lake sedimentary record provide a unique opportunity to develop and calibrate a method to estimate the abundances of the major components of a typical lake sediment (carbonates, organic matter, and the residual mineral fraction) using scanning x-ray fluorescence (XRF) analysis and geochemical data from the core. The purpose of developing this method is to allow estimation of major components to guide decisions for other detailed analytical work. This research project is a part of a larger USGS project aimed at reconstructing changes in the Holocene hydrology and climate (hydroclimate) of the Upper Colorado River Basin, including the White River Plateau, using lake sediments. Interpretations from this project will add to the ongoing USGS study, and our understanding of millennial-scale Holocene climate variability on the plateau.
Landscape Evolution and a Relict Fish Community, North Slope, Alaska
(2005-04) Rantala, Heidi Marie
The North Slope of the Brooks Range in arctic Alaska has a complex glacial history, having been glaciated several times since the late Tertiary. As a result of these glaciations, a complex arrangement of glacial sediments is exposed on the tundra. It is the presence of the youngest glacial sediments, and their abundant lakes, which allows communities of fish to persist in this harsh environment. Although the importance of the lakes is known, the timing at which fish entered and become land-locked in specific lakes is not. The purpose of this study was to use paleolimnological information in an arctic lake, Fog Lake 3, to reconstruct the fish community dynamics in the lake, resulting from glacial and geomorphic processes on the landscape. Information about past conditions in the lake was inferred from biotic evidence and sediment characteristics in a lake sediment core. Grain size, lithology, and carbon chemistry were used as proxies for processes occurring in the lake and its watershed. The chironomid community structure was recreated throughout the length of the core by identification of fossil remains. The core was dated using 14C techniques to determine total age and sedimentation rates throughout the length of the core. The core was divided into two zones based on constrained incremental sum of squares cluster (CONISS) analysis of the grain size data. Although the CONISS analysis created zones, the only differences in grain size characteristics between zones were marginally significant. There was little difference in the carbon chemistry in the two zones. There appeared to be a significant decrease in the mass lost on ignition at 1000°C, but that mass is likely related to water in the mineral structure of clays and not proportion of carbonate rock. Zones in the core were also developed using the CONISS method on the chironomid community composition data. While Tanytarsini (Tanytarsus and Paratanytarsus) dominated the chironomid community throughout the core, the upper zone had higher community diversity, as determined using the Shannon index. The upper zone (Zone 2) was further broken down using the CONISS results into Zones 2a and 2b. Comparison of the two zones showed an increase in chironomid diversity, an increase in Heterotrissocladius relative abundance, and a decrease in the proportion Tanytarsini through time. The evidence presented by this study suggests that the chironomid community composition was controlled by some factor or factors, possibly including fish community structure, which changed through time. The changes seen in the chironomid community are inconsistent with those expected if they were due to climate dynamics or major changes in lake levels. Increasing diversity of the chironomid community would be expected with increased predation pressures, such as those imposed on invertebrates by fish or with increased organic matter input to the lake sediments. The initial presence of fish in the lake possibly are related to changes in the diversity of the chironomid community which occurred between 7973±50 14C YBP and 7344±45 14C YBP. Based on an increase in the chironomid community diversity, the best estimate of fish becoming landlocked in Fog Lake 3 is between 4230 and 4600 14C YBP.
A tunnel speleothem based stable-isotope record of Atlantic Multi-Decadal Oscillation forcing of precipitation in the Midlands, United Kingdom
(2019-08) Shull, Carolyn
Cave speleothems are an established source of preserved data used in paleo-environmental reconstruction, as climate and land use information can be recorded in the carbon and oxygen isotopes. Speleothems in the tunnels of the canals in West Midlands, UK were investigated as another potential record as they appear to experience a rapid growth rate, a requirement to detect short-term climate events and low-amplitude climate signals. Formation in artificial structures restrict the potential record to the past 150 years, while other speleothem-based proxies span millennial time scales. Upon analysis, speleothem oxygen isotopes reflect the Atlantic Multi-Decadal Oscillation (AMO), and carbon and oxygen isotopes are correlated to land use changes. The results indicate speleothems from canal tunnels in central England potentially provide a record of land use changes and precipitation source water related to the AMO. Tunnel speleothem isotope data have the potential to serve as valuable datasets in climate teleconnection and modeling studies.
Isotopic Signatures of Precipitation and Streams along the North Shore of Lake Superior
(2019-06) Stoll, Kinzey
Lake Superior is the largest of the Great Lakes. Its size impacts precipitation along the North and South Shores, but the magnitude of its effects on the North Shore are unknown. Using stable isotopes of δ2H and δ18O to understand the source and transport of precipitation allows us to develop a deeper understanding of the hydrologic cycle in the region and the possible impact of the lake on precipitation. Samples were collected from five snow storms from November 2017 to March 2018, snowmelt from April 2018, and streamflow from May to August 2018. To further examine the hydrologic cycle along the North Shore, the Lester River watershed was studied for spatial and temporal variations from May to December 2018. This watershed, like many others along the North Shore, is a designated trout stream. Water samples collected from the stream and from precipitation were used to show seasonal trends and spatial variability across the watershed. This information highlights the timing of different processes in the watershed such as evaporation. Temperature data was also collected throughout the watershed to show conditions for trout and provide more information on hydrologic processes.
Effects of Vegetation-Sediment Interactions on the Morphological Evolution of Coarse-Bedded Rivers: Results from Flume Experiments
(2017-07) Batts, Virginia
Laboratory experiments over the past two decades have demonstrated the crucial role of vegetation in determining the morphological characteristics of river channels. Through a series of flume experiments, this research builds on previous studies by examining the respective role of both vegetation and sediment load composition on resulting channel planform style and dynamics as vegetation density increases. I used a 1.5 m by 6 m flume filled with well-sorted quartz sand (D50 = 0.5 mm) to simulate a gravel-bedded river. Each experiment simulated a series of 4-hour floods, after each of which the flume was seeded with alfalfa (Medicago sativa) so that vegetation density increased with each flood. The only variable between the two experiments was the composition of the sediment feed. We fed only bed load in Experiment 1, and fed both bed load and suspended load in Experiment 2. Results confirm the findings of earlier experiments in that vegetation progressively stabilized the surface of the flume, limiting the number of channel threads until only one remained. The resulting channel was deeper, faster, and narrower than the unvegetated channel. Results suggest that vegetation-sediment interactions can produce widely differing channel morphology depending on the composition of sediment load and the frequency of overbank flows. They also demonstrate that while bed load transport within a channel with strengthened banks is critical for the generation of a meandering pattern by building bars, fine sediment may play an equally important role in adjusting floodplain topography. The amount, distribution, and storage of sediment trapped in the riparian corridor were directly related to vegetation density and the presence of overbank flow conditions.
Seasonal and Flood-Induced Variations in Groundwater-Surface Water Exchange Dynamics in a Shallow Aquifer System: Amity Creek, MN
(2016-01) Jasperson, Jenny
Excellent brook trout habitat can be found in segments of many streams on the North Shore of Lake Superior. Optimal riverine brook trout habitat includes clear, cold spring-fed water and studies have shown that areas of groundwater upwelling in streams tend to be more important than other site selection variables. Observations of historical brook trout and temperature data in the Amity Creek sub-watershed of Lake Superior South HUC-8 led us to hypothesize that reaches with healthy and stable brook trout communities are likely connected to groundwater storage, exchange, and upwelling. Climate trend models for the Midwest predict future changes in temperature, annual precipitation, and storm event frequency for Northern Minnesota. Streams along the North Shore of Lake Superior are susceptible to increased temperatures and insufficient late summer to early winter flows due to climate change and the unique regional geology. Understanding groundwater-surface water hydrology interactions, watershed connectivity, and related flood-induced geomorphic and hydrologic changes is important because they relate to the overall stability and aquatic health of the stream and the biological communities that inhabit it. The objectives of this study were to identify groundwater storage zones, upwelling zones and seasonal variations; and assess how these relationships change as result of a major flood. A study reach on East Branch Amity Creek is incising through clay-rich glacial tills overlying bedrock and has avulsed multiple times in the past, stranding discrete remnant channels cut into till. A 500-year storm hit Duluth, MN, USA on June 19-20th 2012, producing 8-inches of rain in a 24-hour duration which resulted in flash flooding across the region. Pre-flood and post-flood groundwater and surface water level data were collected through a series of piezometers with pressure transducers and an in-channel stream gage. Stable isotope analyses of Deuterium and Oxygen-18 were conducted on water samples with varying temporal and spatial variability to provide information on watershed and reach scale source hydrology and evaluate flood-induced changes. Results show groundwater upwelling variability within the greater watershed and identify two discrete groundwater storage zones within a smaller study reach. Pre- and post-flood analyses show a correlation between incision in main stem and remnant channels and a lowered water table, following the flood. Isotope analysis indicates a temporary post-flood change in subsurface source water. Because much of the greater North Shore of Lake Superior has the same geology as the study area, the results of this study may provide insight to hydrology studies of other North Shore streams.
Identifying erosional hotspots in streams along the North Shore of Lake Superior, Minnesota using high-resolution elevation and soils data
(2013-09) Wick, Molly Jane
Many streams on the North Shore of Lake Superior, Minnesota, USA, are impaired for turbidity driven by excess fine sediment loading. The goal of this project was to develop a GIS-based model using new, openly-available, high-resolution remote datasets to predict erosional hotspots at a reach scale, based on three study watersheds: Amity Creek, the Talmadge River, and the French River. The ability to identify erosional hotspots, or locations that are highly susceptible to erosion, using remote data would be helpful for watershed managers in implementing practices to reduce turbidity in these streams. Erosion in streams is a balance between driving forces, largely controlled by topography; and resisting forces, controlled by the materials that make up a channel's bed and banks. New high-resolution topography and soils datasets for the North Shore provide the opportunity to extract these driving and resisting forces from remote datasets and possibly predict erosion potential and identify erosional hotspots. We used 3-meter LiDAR-derived DEMs to calculate a stream power-based erosion index, to identify stream reaches with high radius of curvature, and to identify stream reaches proximal to high bluffs. We used the Soil Survey Geographic (SSURGO) Database to investigate changes in erodibility along the channel. Because bedrock exposure significantly limits erodibility, we investigated bedrock exposure using bedrock outcrop maps made available by the Minnesota Geological Survey (MGS, Hobbs, 2002; Hobbs, 2009), and by using a feature extraction tool to remotely map bedrock exposure using high-resolution air photos and LiDAR data. Predictions based on remote data were compared with two datasets. Bank Erosion Hazard Index surveys, which are surveys designed to evaluate erosion susceptibility of banks, were collected along the three streams. In addition, a 500-year flood event during our field season gave us the opportunity to collect erosion data after a major event and validate our erosion hotspot predictions. Regressions between predictors and field datasets indicate that the most significant variables are bedrock exposure, the stream power-based erosion index, and bluff proximity. A logistic model developed using the three successful predictors for Amity Creek watershed was largely unsuccessful. A threshold-based model including the three successful predictors (stream power-based erosion index, bluff proximity, and bedrock exposure) was 70% accurate for predicting erosion hotspots along Amity Creek. The limited predictive power of the models stemmed in part from differences in locations of erosion hotspots in a single large-scale flood event and long-term erosion hotspots. The inability to predict site-specific characteristics like large woody debris or vegetation patterns makes predicting erosion hotspots in a given event very difficult. A field dataset including long-term erosion data may improve the model significantly. This model also requires high resolution bedrock exposure data which may limit its application to other North Shore streams.

University Digital Conservancy

University of Minnesota Duluth

Browse

Recent Submissions