Physical Sciences and Mathematics Commons^™

Development Of A Decision Support System Webtool For Historic And Future Low Flow Estimation In The Northeast United States With Applications Of Machine Learning For Advancing Physical And Statistical Methodologies, Andrew F. Delsanto

Doctoral Dissertations

Droughts are a global challenge and anthropogenic climate change is expected to increase the frequency and severity of extreme low flow events. A major challenge for resource managers is how best to incorporate future climate change projections into low flow event estimations, especially in ungaged basins. Using both physically based hydrology models and statistical models, this dissertation contributes novel methodologies to three key challenges associated with 7-day, 10-year low flow (7Q10) estimation in the northeast United States. Chapter 2 builds upon statistically based 7Q10 estimation in ungaged basins by comparing multiple machine learning algorithms to classical statistical methodologies. This chapter’s …

Heat Flow In The Southern Margin Of Salar De Atacama: Deep Groundwater Temperature Distributions And The Implications For Subsurface Flow And Land Surface Energy Budgets, Graham Thomas

Masters Theses

Salar de Atacama (SdA) located in Northern Chile is home to one of the planet’s largest salar systems and lithium resources. Managing groundwater resources in salars is not obvious due to the lack of scientific understanding on the connectivity between the freshwater and brine systems. Using heat as a tracer in SdA provides a cost-effective method to further investigate groundwater flow in salars. This study employs 372 temperature-depth profiles from 90 boreholes between 2013-18 to understand the distinct thermal zones and flow between them in SdA. Three thermal zones exist within the southern margin of SdA’s thermal regime, at higher …

Modeling Spatial Distributions Of Tidal Marsh Blue Carbon Using Morphometric Parameters From Lidar, Bonnie Turek

Masters Theses

Tidal marshes serve as important “blue carbon” ecosystems that accrete large amounts of carbon with limited area. While much attention has been paid to the spatial variability of sedimentation within salt marshes, less work has been done to characterize spatial variability in marsh carbon density. Driven by tidal inundation, surface topography, and sediment supply, soil properties in marshes vary spatially with several parameters, including marsh platform elevation and proximity to the marsh edge and tidal creek network. We used lidar to extract these morphometric parameters from tidal marshes to map soil organic carbon (SOC) at the meter scale. Fixed volume …

Size, Timing, And Landscape Impacts Of Glacial Lake Outburst Floods In The Channeled Scabland Of Eastern Washington, Usa, Karin E. Lehnigk

Doctoral Dissertations

Extreme floods have dramatically altered landscapes on Earth and Mars through bedrock erosion, sediment deposition, and canyon formation. The Channeled Scabland of the Columbia Plateau in eastern Washington, USA, is perhaps the most striking example of such a landscape, where outburst floods from an ice-dammed glacial Lake Missoula eroded immense canyons and transported large volumes of sediment during the late Pleistocene. Despite advances in numerical modeling and geochemical exposure dating methods, it has remained a challenge to untangle the complex interactions between floodwater, bedrock, and glacial ice to link the size of a flood with its impact on the landscape. …

Remote Sensing Of High Latitude Rivers: Approaches, Insights, And Future Ramifications, Merritt E. Harlan

Doctoral Dissertations

High latitude rivers across the pan-Arctic domain are changing due to changes in climate and positive Arctic feedback loops. Understanding and contextualizing these changes is challenging due to a lack of data and methods for estimating and modeling river discharge, and mapping rivers. Remote sensing, and the availability of satellite imagery can provide ways to overcome these challenges. Through combining various forms of fieldwork, modeling, deep learning, and remote sensing, we contribute methodologies and knowledge to three key challenges associated with better understanding high latitude rivers. In the first chapter, we combine field data that can be rapidly deployed with …

Perceptions Of Historical Climate Change And Park Policy: The Impact On The Fremont Cottonwood In Zion National Park, Kathleen Kavarra Corr

Doctoral Dissertations

Despite its “natural” appearance and the Organic Act 1916 mandate for preservation of the natural environment in National Parks, the Virgin River as it flows through Zion National Park’s Zion Canyon was transformed through massive flood control re-engineering projects in the 1930s. The armoring of the river has had significant impacts on riparian vegetation, particularly on the stands of native Fremont Cottonwood trees that once filled the narrow valley. What was the motivation for this massive flood control project carried out in an arid region with less than 15 inches of rain per year? This dissertation explores the motivations which …

Improving The Hydrological Analysis Of Groundwater Flow Paths By Integrating Geochemical And Physical Characteristics Of A Highly Fractured Aquifer System To Create Sustainable Use Of Groundwater In A Climate With Projected Drying Trends., Marsha K. Allen

Doctoral Dissertations

Improving the hydrological analysis of groundwater flow paths by integrating geochemical and physical characteristics of a highly fractured aquifer system to create sustainable use of groundwater in a climate with projected drying trends. Precipitation over Caribbean islands has decreased steadily since the 1950's, which has led to severe drought conditions. The most recent Pan-Caribbean Drought occurred from 2013 to 2016. Climate models predict that drying trends are expected to continue and become more severe over time as precipitation decreases and temperatures rise. In addition, evaporation rates on these islands are expected to increase by ~15-17%, contributing to the drought. Though …

Fundamental Controls On The Water Cycle In Arid Environments: A Mechanistic Framework For Spatiotemporal Connectivity Between Hydroclimate And Groundwaters In The Dry Andes, Brendan J. Moran

Doctoral Dissertations

There remain many persistent uncertainties regarding fundamental aspects of natural water cycles in arid mountainous regions, the Dry Andes of South America represents one of the most extreme examples of these environments on the Planet. Deep water tables (>100 meters), long groundwater transit times and distances (>100 years, 10-100 kilometers), limited and infrequent rainfall, remote and difficult to access terrain, and complex salar/evaporite hydrogeology common in these environments make reliable monitoring of these hydrological systems particularly difficult. As a result, major gaps remain in our understanding of critical aspects of the water cycle such as recharge and evaporation …

Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long

Masters Theses

The cycling of phosphorus (P) through floodplain environments is critical to ecosystem productivity and has significant implications on both water quality and soil fertility. P export from soils in response to saturation has been well documented, but the relative vulnerability of specific P pools to mobilization remains poorly constrained, as do the mechanisms mediating its release. The prediction of P availability in and export from mountainous floodplain soils is of great importance as global climate change is projected to significantly alter precipitation regimes in alpine systems. This study combined a thorough characterization of P distribution across a hillslope to floodplain …

Testing The Impact Of A Freshwater Wetland Restoration On Water Table Elevation And Soil Moisture Using A Parametric Groundwater Modeling Approach, Erika T. Ito

Masters Theses

Wetlands are now recognized for the many social, environmental, ecological, and economic benefits they provide. They improve water quality, support biodiversity, abate floods and storms, and provide local recreational areas. Historically, many wetlands have been drained or altered for residential, commercial, or agricultural use. Effective wetland restoration projects reestablish ecosystem services and mitigate legacy effects of land use change to create self-sustaining systems. However, a persisting lack of scientifically-vetted methodological and evaluation guidelines in the field of restoration ecology has caused many restoration efforts to fail to restore natural wetland hydrologic conditions. By definition, wetlands must be saturated, permanently or …

Coastal Groundwater Catchments Of The Gulf Of Alaska, Aeon Russo

Masters Theses

High latitude mountain environments are experiencing disproportionately adverse effects in a currently changing climate. The Gulf of Alaska (GoA) region is an exemplar of this. Dramatic shifts are occurring in the region’s freshwater reservoirs as glaciers retreat more with each passing year. Research in the region places much focus on observing and predicting climate driven shifts in glacier mass balance, surface discharge, and associated nutrient fluxes to the ocean. On the other hand, coastal groundwater discharge (CGD) is given very little attention. Global and near-global estimates of CGD indicate variable results spanning an order of magnitude. Focusing on regionally specific …

Processes, Patterns, And Predictions Of Soil Moisture Variation In Upland And Peatland Cranberry Farms In Massachusetts, Rebecca Brennan

Masters Theses

The American Cranberry (Vaccinium macrocarpon Ait.) represents a vital sector of the economy of southeastern Massachusetts. Due to the hydrogeological and edaphic characteristics of peatlands, variations in soil drainage and soil moisture represent major management challenges for growers in Massachusetts. An emerging trend of upland (mineral soil) cranberry farms planted with new hybrid cultivars has the potential to enhance the profitability and long-term viability of cranberry production in Massachusetts. However, sparse data exist on soil moisture characteristics of peatland and upland cranberry farms. The purpose of this research was to elucidate the differences in soil moisture between upland and …

Defining And Addressing Interconnected Goals In Groundwater Management Planning Across The Usa, Allison Gage

Masters Theses

Groundwater accounts for approximately 99% of the available freshwater on Earth, and is an important resource for irrigation, potable water, and domestic use in the United States. However, the overuse of groundwater has led to aquifer depletion in several basins across the USA, resulting in storage reduction, contamination, salt water intrusion, and depletion of surface waters. To properly manage groundwater for the future, there is a need for well-informed Groundwater Management Plans (GWMPs) in order to prevent further depletion and erosion of the resource. Previous studies have focused on groundwater management relative to groundwater laws, regulations, and institutional arrangements. This …

Spatial And Temporal Mapping Of Distributed Precipitation, Surface And Groundwater Stable Isotopes Enables Insights Into Hydrologic Processes Operating At A Catchment Scale, Alison Cole

Masters Theses

Isotopic analyses of d¹⁸O and d²H of water through the hydrologic cycle have allowed hydrologists to make better interpretations related to climate and relationships between precipitation, surface water, and groundwater. In this study 394 precipitation samples 1917 surface water samples and 1405 groundwater samples across Massachusetts was used to create an isoscape for each respective water. All samples have been collected by volunteers throughout Massachusetts. A state meteoric water line: d²H = 7.7*d¹⁸O + 9.8, surface water line: d²H = 5.7*d¹⁸O – 4.2, and groundwater line: d^{2 …}

Hydrologic Structure And Function Of Vernal Pools In South Deerfield, Massachusetts, Charlotte Axthelm

Masters Theses

Vernal pools are small, ephemeral wetlands lacking an inlet or outlet. These wetlands, also known as seasonal pools, are found in a wide range of biomes, and their characteristics vary based on location. While the vegetation of western U.S. pools, and amphibians of eastern U.S. pools have been extensively studied, many aspects of vernal pools have not been fully characterized. In particular, although the general seasonal wetting and drying cycle is understood qualitatively, few studies have attempted to quantify the hydrological regime of vernal pools in New England. As water level variation drives many, if not all, of the characteristics …

The Climatic And Hydrostratigraphic Controls On Brine-To-Freshwater Interface Dynamics In Hyperarid Climates: A 2-D Parametric Groundwater Modeling Study, Sarah Mcknight

Masters Theses

Density dependent flow occurs in areas where high-salinity groundwater interacts with low-salinity groundwater to create a brine-to-freshwater interface that defies common assumptions about groundwater movement. Yet the geologic and hydrologic factors that impact interface dynamics and migration remain poorly defined. With less than 20 mm•yr^-1 of precipitation and with an extremely dense (i.e. 1.2 g•cm^-3) naturally occurring brine, Chile’s Salar de Atacama (SdA) provides an excellent analog for exploring interface dynamics in other arid regions. Site-specific 2-D models of the interface in the southeastern region of SdA, with interpretations of the hydrostratigraphic framework, provide an analysis for …

The River Process Corridor: A Modular River Assessment Method Based On Process Units And Widely Available Data In The Northeast Us., John D. Gartner, Christine E. Hatch, Eve Vogel, Et. Al.

Water Reports

We define the river process corridor (RPC) as the area adjacent to a river that is likely to affect and be affected by river and floodplain processes. Here we present a novel approach for delineating the RPC that utilizes widely available geospatial data, can be applied uniformly across broad and multi-scalar spatial extents, requires relatively low levels of expertise and cost, and allows for modular additions and adaptations using additional data that is available in particular areas. Land managers are increasingly using a variety of delineated river and floodplain areas for applied purposes such as hazard avoidance, ecological conservation, and …

River And Stream Power Assessment Report Including Culvert And Bridge Vulnerability Analysis: Deerfield River Basin, Massachusetts And Vermont, James G. Macbroom, Roy Schiff, Jessica Louisos

Water Reports

This geomorphic assessment of Deerfield River in western Massachusetts and southern Vermont has been prepared by Milone & MacBroom, Inc. (MMI) on behalf of the University of Massachusetts as part of its "Farms, Floods, and FGM" project, funded by the United States Department of Agriculture – National Institute of Food and Agriculture National Integrated Water Quality Program(USDA – NIFA NIWQP) program. This project is a broad-based geomorphic assessment of the Deerfield River and its adjacent riparian corridor to define its characteristics, processes, and management issues. The river channel is used extensively for hydroelectric power generation and recreation, with agricultural …

Geochemical Attributes Of Hydraulically Active Fractures And Their Influence On Groundwater Quality, Amy L. Hudson

Doctoral Dissertations

This study utilized discrete interval diffusion sampling of a fractured bedrock well completed in schist to investigate if a natural weathering signal can be used to identify hydraulically active fractures. The open borehole well MFS-1, is the focus of the study, which is in close proximity to the recharge zone making it ideal for testing the hypotheses of this study. The hydraulically active fractures of Well MFS-1 were identified, and the dominant mixing force of the water column of the well was determined to be thermal convection in the upper portion of the well and upward gradients. The isotopic data …

Sources Of Water And Solutes To The Salar De Atacama, Chile: A Coupled Hydrologic, Geochemical, And Groundwater Modeling Study, Lilly G. Corenthal

Masters Theses

Focused groundwater discharge in endorheic basins provides opportunities to investigate mechanisms for closing hydrologic budgets in arid regions. The Salar de Atacama (SdA), a closed basin in northern Chile, has accumulated over 1800 km³ of halite and a lithium-rich brine since the late Miocene primarily through evapotranspiration of groundwater. The hydrologic balance of SdA and sources of water and solutes required to explain this deposit are not well constrained. An adapted chloride mass balance method drawing on a database of over 200 water sample sites is applied to a remotely-sensed precipitation dataset to estimate spatially-distributed modern groundwater recharge. Comparing …

Using Digital Elevation Models Derived From Airborne Lidar And Other Remote Sensing Data To Model Channel Networks And Estimate Fluvial Geomorphological Metrics, Noah Slovin

Masters Theses

Recent advances in remote-sensing technologies and analysis methods, specifically airborne-LiDAR elevation data and corresponding geographical information system (GIS) tools, present new opportunities for automated and rapid fluvial geomorphic (FGM) assessments that can cover entire watersheds. In this thesis, semi-automated GIS tools are used to extract channel centerlines and bankfull width values from digital elevation models (DEM) for five New England watersheds. For each study site, four centerlines are mapped. LiDAR and NED lines are delineated using ArcGIS spatial analyst tools with high-resolution (1-m to 2-m) LiDAR DEMs or USGS National Elevation Dataset (NED) DEMs, respectively. Resampled LiDAR decreases LiDAR DEM …

Impacts Of Three-Dimensional Non-Uniform Groundwater Flows For Quantifying Groundwater-Surface Water Interactions Using Heat As A Tracer, Jonathan M. Reeves

Masters Theses

Heat-as-a-tracer has become a common method to quantify surface water-groundwater interactions (SW/GW). However, the method relies on a number of assumptions that are likely violated in natural systems. Numerical studies have explored the effects of violating these fundamental assumptions to various degrees, such as heterogeneous streambed properties, two-dimensional groundwater flow fields and uncertainty in thermal parameters for the 1-dimensional heat-as-a-tracer method. No work to date has addressed the impacts of non-uniform, three-dimensional groundwater flows on the use of heat-as-a-tracer to quantify SW/GW interactions. Synthetic temperature time series were generated using COMSOL Multiphysics for a three-dimensional cube designed to represent a …

Hydrogeological Control On Spatial Patterns Of Groundwater Seepage In Peatlands, Danielle K. Hare

Masters Theses

Groundwater seepage to surface water is an important process to peatland ecosystems; however, the processes controlling seepage zone distribution and magnitude are not well understood. This lack of process-based understanding makes degraded peatland ecosystems difficult to restore and problematic for resource managers developing a sustainable design. Degraded peatlands, particularly abandoned cranberry farms, often have drainage ditches, applied surface sand, and decreased stream sinuosity to artificially lower the water table and support agriculture. These modifications disconnect the surface and groundwater continuum, which decreases thermal buffering of surface water significantly. The combination of a decreased influx of thermally buffered groundwater, a naturally …

The Active River Area (Corridor), Christine E. Hatch

Water Fact Sheets

This is a Fact Sheet created by RiverSmart for the Fluvial Geomorphology Task Force defining methods for delineating a river corridor. The “Active River Area,” is defined as the place where hydrologic connectivity, floodplain hydrology, and sediment movement occur along the river corridor.

Qualitative And Comparative Analysis Of Stormwater Management In The Tan Brook Watershed, Natalia Von Hausen, Robert F. Smith

Research

The Tan Brook Watershed is both a daylighted and diverted underground stream that runs through the Town Center of Amherst and the campus of UMass Amherst. Various stormwater management practices have been used to infiltrate stormwater runoff from streets, lots, buildings and/or vehicles. These systems are custom-designed relative to the surrounding permeability of the soil, vegetation and geographical topography. Some systems have higher success rates than others.

Ecohydrologic Impacts Of Climate And Land Use Changes On Watershed Systems: A Multi-Scale Assessment For Policy, Paul A. Ekness

Open Access Dissertations

Maintaining flows and quality of water resources is critical to support ecosystem services and consumptive needs. Understanding impacts of changes in climate and land use on ecohydrologic processes in a watershed is vital to sustaining water resources for multiple uses. This study completes a continental and regional scale assessment using statistical and simulation modeling to investigate ecohydrologic impacts within watershed systems.

Watersheds across the continental United States have diverse hydrogeomorphic characters, mean temperatures, soil moistures, precipitation and evaporation patterns that influence runoff processes. Changes in climate affect runoff by impacting available soil moisture, evaporation, precipitation and vegetative patterns. A one …

Uncertainty In Climatic Change Impacts On Multiscale Watershed Systems, Olga V. Tsvetkova

Open Access Dissertations

Uncertainty in climate change plays a major role in watershed systems. The increase in variability and intensity in temperature and precipitation affects hydrologic cycle in spatial and temporal dimensions. Predicting uncertainty in climate change impacts on watershed systems can help to understand future climate-induced risk on watershed systems and is essential for designing policies for mitigation and adaptation. Modeling the temporal patterns of uncertainties is assessed in the New England region for temperature and precipitation patterns over a long term. The regional uncertainty is modeled using Python scripting and GIS to analyze spatial patterns of climate change uncertainties over space …

The Role Of Structural Stormwater Best Management Practices, Impervious Surfaces And Natural Factors On Base Flow In Massachusetts, Kimberly B. Klosterman

Masters Theses 1911 - February 2014

This research conducted a GIS analysis of twenty-eight sub-watersheds in Massachusetts and considered five factors which the literature suggested influenced base flow. The literature suggested a positive relation between precipitation, forest cover and base flow and a negative relationship between impervious surfaces, soil drainage class, slope and base flow. A multiple regression analysis of the sub-watershed information confirmed the literature for two factors (soil drainage class and slope) and questioned it on three factors (impervious surfaces, precipitation, and forest cover). The resulting predictive equation indicated that imperviousness and precipitation were the most significant factors affecting base flow. The first derivative …

How Does Hydropeaking Alter The Hydrology Of A River Reach? A Combined Water Budget, Modeling, And Field Observation Study. Deerfield River, Massachusetts, Brian C. Yellen

Masters Theses 1911 - February 2014

Hydroelectric releases on the Deerfield River in northwestern Massachusetts affect surface water-groundwater interactions there by daily reversing the head gradient between river and groundwater. Artificially elevated stage drives river water into the riparian aquifer. Water budget analysis indicates that roughly 10% of this bank-stored water is permanently lost from the river system in a 19.5 km reach, likely as a result of transpiration by bank vegetation.

Field observations as well as two-dimensional modeling results show that water losses are not uniform throughout the study reach. Riparian aquifer transmissivity in river sub-reaches largely determines the magnitude of surface water-groundwater exchange as …

A Paleoclimate Modeling Experiment To Calculate The Soil Carbon Respiration Flux For The Paleocene-Eocene Thermal Maximum, David M. Tracy

Masters Theses 1911 - February 2014

The Paleocene-Eocene Thermal Maximum (PETM) (55 million years ago) stands as the largest in a series of extreme warming (hyperthermal) climatic events, which are analogous to the modern day increase in greenhouse gas concentrations. Orbitally triggered (Lourens et al., 2005, Galeotti et al., 2010), the PETM is marked by a large (-3‰) carbon isotope excursion (CIE). Hypothesized to be methane driven, Zeebe et al., (2009) noted that a methane based release would only account for 3.5°C of warming. An isotopically heavier carbon, such as that of soil and C3 plants, has the potential to account for the …