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- Debris avalanches (1)
- Evapotranspiration (1)
- Machine learning (1)
- Microplastics (1)
- Post-fire forest management -- Oregon (1)
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- Runoff -- Climatic factors -- West (U.S.) (1)
- Runoff -- Oregon -- Mathematical models (1)
- Soil erosion (1)
- Water -- Pollution -- Environmental aspects -- Oregon -- Portland (1)
- Water -- Pollution -- Seasonal variations -- Oregon -- Portland (1)
- Wildfires -- Environmental aspects -- West (U.S.) (1)
- Wildfires -- West (U.S.) -- Mathematical models (1)
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Spatial Analysis Of Burn Severity And Streamflow Response In The Western Conus, Will Brendan Long
Spatial Analysis Of Burn Severity And Streamflow Response In The Western Conus, Will Brendan Long
Dissertations and Theses
Wildfire increases the magnitude of runoff in catchments, which can lead to the degradation of ecosystems, risk to infrastructure, and loss of life. The Labor Day Fires of 2020 provided an opportunity to compare multiple large and severe wildfires with the objective of determining potential changes to hydrologic processes in Oregon Cascades watersheds. Geographic information systems (GIS) were implemented to determine the total percentage burned and percentage of high burn severity class of six watersheds on the west-slope of the Oregon Cascade Range. In addition, two control watersheds were included to contrast the influence of climatic effects. Spatial arrangement of …
Post-Fire Erosional And Hydrological Processes Promoting Debris Flow Initiation In A Douglas Fir And Western Hemlock Forest In The Riverside Burn Area, Oregon, Morena Nicole Hammer
Post-Fire Erosional And Hydrological Processes Promoting Debris Flow Initiation In A Douglas Fir And Western Hemlock Forest In The Riverside Burn Area, Oregon, Morena Nicole Hammer
Dissertations and Theses
Post-fire debris flows initiated by overland flow in the Pacific Northwest (PNW) are largely undocumented. Instead, debris flows are typically initiated by shallow landslides that result in a mud slurry of water and sediments traveling downhill under the force of gravity. However, because of the Fall 2020 fires in Oregon, the typical initiation style and erosional patterns in burned catchments may have changed because of unusually high burn severity. Due to the intensity of these fires, we set out to determine how hydrologic processes and erosion occurred, when they occurred, and what process was primarily responsible for the erosion that …
Learning From Machines: Insights In Forest Transpiration Using Machine Learning Methods, Morgan Tholl
Learning From Machines: Insights In Forest Transpiration Using Machine Learning Methods, Morgan Tholl
Dissertations and Theses
Machine learning has been used as a tool to model transpiration for individual sites, but few models are capable of generalizing to new locations without calibration to site data. Using the global SAPFLUXNET database, 95 tree sap flow data sites were grouped using three clustering strategies: by biome, by tree functional type, and through use of a k-means unsupervised clustering algorithm. Two supervised machine learning algorithms, a random forest algorithm and a neural network algorithm, were used to build machine learning models that predicted transpiration for each cluster. The performance and feature importance in each model were analyzed and compared …
Spatial And Seasonal Variations Of Microplastic Concentrations In Portland's Freshwater Ecosystems, Rebecca Talbot
Spatial And Seasonal Variations Of Microplastic Concentrations In Portland's Freshwater Ecosystems, Rebecca Talbot
Dissertations and Theses
Microplastics are a pollutant of growing concern and are ubiquitous in a variety of environmental compartments. The majority of microplastics research to date has been conducted in marine waters, and less is known regarding the sources and delivery pathways of microplastics in urban rivers. The first chapter is comprised of a review of the scientific literature regarding the spatial and temporal factors affecting global freshwater microplastic distributions and abundances. Microplastic spatial distributions are heavily influenced by anthropogenic factors, with higher concentrations reported in regions characterized by urban land cover, high population density, and wastewater treatment plant effluent. Temporal variables of …