As global atmospheric carbon emissions continue to rise, scientists and land managers are increasingly looking to natural ecosystems to sequester and store carbon to buffer the impacts of climate change. Despite their small geographic size, many coastal ecosystems such as salt marshes, seagrass meadows, and mangroves sequester large amounts of...
This thesis contains a manuscript describing the implementation of a high resolution wave forecasting model for the coasts of Washington and Oregon. The purpose of this project was to advance the wave predictive capabilities of the states of Oregon and the southwest part of Washington by including the effects of...
Synthetic-aperture radar (SAR) imagery can provide wavenumber and frequency data to generate bathymetry estimates for locations where limited access or extreme ocean conditions can make standard bathymetry survey techniques difficult or impossible. The availability of SAR data could allow for regular bathymetry estimates of navigational channels providing insight into dredging...
Coastal communities throughout the U.S. Pacific Northwest face heightened risk due to sea level rise and increasing storminess resulting in coastal flooding and erosion hazards. Incorporating uncertainty with respect to both climate change and policy decisions is essential to project the evolving probability of coastal inundation and erosion, and the...
In order to evaluate the shallow stratigraphy along the southern Cascadia abyssal margin and northern California abyssal plain, CHIRP subbottom profiles capable of imaging individual turbidite beds in the upper tens of meters of the subsurface were collected. Reflectors imaged with the 3.5 kHz CHIRP subbottom data represent turbidite beds...
This research considers the availability of the appropriate geospatial data in support of
vulnerability mapping of the Oregon coast. An online experiment, Voicing Climate Concerns,
was developed to give community stakeholders, researchers and other interested parties the
opportunity to voice their concerns on climate change and their perceived vulnerability to...
This thesis is comprised of a manuscript based on a laboratory experiment run in the Tsunami Wave Basin as part of a research project funded by the Network for Earthquake Engineering Simulation called Housesmash. The purpose of the experiment was to better understand the role of the urban environment, represented...
Passive hydrophone technologies and a variety of acoustic methods are applied in
the deep-ocean and shallow water coastal environments of the northeast Pacific. A
catalog derived from U.S. Navy regional hydrophone array recordings of acoustic T- phases from seafloor earthquakes is examined, describing space/time patterns through
empirical orthogonal function analysis...
Changes in the stable carbon isotope composition of carbonate rocks (𝛿13Ccarb) are used to establish the relative temporal framework for geological events, such as evolutionary extinction or radiation, between two or more locations. As every local stratigraphic record is intermittent, aligning 𝛿13Ccarb records from two or more locations, a process...
Wave runup is an important physical process that affects nearshore sediment transport, coastal erosion, and flooding. Large and unexpected runup events can also be dangerous to beach goers. Extreme runup statistics are essential parameters used in engineering design of marine structures and in coastal management. Although the study of runup...
This thesis presents two conceptually linked papers outlining methodologies to improve community resilience. Both papers employ Seaside, Oregon as a testbed community and consider the seismic-tsunami hazard posed by the Cascadia Subduction Zone. The first paper presents a framework to deaggregate the results of a multi-hazard, multi-infrastructure, damage analysis by...
Coastal sand dunes and beaches offer a variety of ecosystem services such as coastal protection, sand stabilization, species conservation, and recreation. However, the management and balance of ecosystem services offered by dunes and beaches is challenging when ecosystem services interact across the landscape. Management focusing only on one ecosystem service...
The understanding and prediction how coastal wetland vegetation attenuates wave action has received renewed attention with global climate change impacts and increasing populations on coastlines. Conventional attenuation models utilize empirical drag coefficients, but these coefficients exhibit a wide range of values, and there is some uncertainty in the relative importance...
Radiation stresses, defined as the excess flow of momentum due to the presence of waves (Longuet-Higgins, 1964), are the main drivers behind the cross-shore and longshore forcing that results in wave setup, set-down, and longshore currents (e.g. Svendsen, 2006). Longshore currents entrain and transport sediment and therefore play an important...
Estuaries represent the confluence of land and ocean environments and encompass a number of complex interactions amongst tides, winds, offshore waves and the riverine contributions, all of which contribute to total water levels (TWLs). The study of TWLs and the relative weight of its components can assist local communities in...
Antarctic Ice Sheet mass balance and, hence, sea level change is affected by the floating extensions of outlet glaciers and ice streams that take up about 44% of the coastline (Drewry et al., 1982) and are referred to as "ice shelves". Ice sheet mass loss accelerates when these ice shelves...
Coastal vegetation dampens waves which can provide benefits to the local area, but existing literature shows large variations in the degree of wave height attenuation depending on plant properties and wave conditions. Better knowledge of how to predict the wave height decay accurately in different types of vegetation may help...
The hazards associated with tsunamis are well known and have been studied for decades. The majority of research is, however, focused on open coastlines which bear the brunt of a tsunamis force. Other regions that can be strongly impacted by a tsunami are large estuaries. Here, the tsunami encounters a...
As the second largest river in the U.S., the entrance to the Columbia River is home to some of the most extreme wave conditions on the Pacific Coast. Winter storms commonly generate waves 6-8 m in height, which in combination with strong tidal currents, can produce dangerous navigation conditions. To...
Throughout the Holocene, appreciable changes in bathymetry are hypothesized to have resulted in large changes to tidal datums in coastal and estuarine areas. An understanding of tidal change is an important contribution to the knowledge of relative historical sea-level change and future coastal planning. To test this hypothesis, the Advanced...
The experimental setup and data are presented for a laboratory experiment conducted to examine realistic wave forcing on a highway bridge superstructure. The experiments measure wave conditions along with the resulting forces, pressures, and structural response of a 1:5 scale, reinforced concrete model of a typical section of the I-10...
Understanding the past, present, and future behavior of our nation's shorelines is vital for sensible coastal management. Localized areas of erosion, termed "erosional hot spots", can shift the shoreline landward threatening coastal infrastructure (Kraus and Galgano, 2001; Stauble and Gravens, 2004; McNinch, 2004). One specific type of erosional hot spot...
Wind flow on vegetated coastal foredunes adapts to the local canopy drag, resulting in spatial gradients in bed shear stresses which contribute to the formation of localized bedforms (e.g., nebkha, shadow dunes). Numerous morphological properties of the plants, including canopy height and density, affect the wind flow dynamics and therefore...
Sandy beaches and dunes cover approximately one-third of the world’s ice-free coastlines and provide ecosystem services including coastal protection, recreation, wildlife habitat, and carbon sequestration. These dynamic interface habitats are variably shaped by wind, waves, sedimentary processes, and vegetation feedbacks. Positive biophysical feedbacks lead to the formation of vegetated coastal...
The formation of beach scarps is a challenging morphodynamic phenomenon that the coastal community has yet to capture in coastal change models. Understanding scarp formation is crucial to accurately predicting coastal erosion and vulnerability during extreme events, as models without parameters for scarp formation and development severely underpredict total erosion...
With rising sea levels and more frequent exposure to extreme storms, coastlines worldwide are vulnerable to increased erosion and loss of natural marsh lands. In an effort to lessen these impacts, there is a growing practice of adapting hard or “gray” coastline protection techniques to more nature-based features that promote...
Ecological communities are connected in space and time through the transfer of energy, materials, and organisms, together known as ecological subsidies. These ecological subsidies can have substantial effects on community structure, function, and services, especially when the connections are between communities with contrasting productivity. At the ocean-land interface, low productivity...
Biological invasions and climate change represent two preeminent threats to ecological communities and biodiversity, altering the distribution and abundance of species, disrupting existing species interactions and forming unprecedented ones, and creating novel ecological communities. Many of the most successful invasive species are also ecosystem engineers, species that physically modify the...
Coastal marsh vegetation is an important component in maintaining marsh stability that is threatened by changes in sedimentation, sea level rise, natural and anthropogenic disturbances, and competition from invasive species. Vegetation has been demonstrated to reduce wave energy, increase sedimentation, and decrease erosion in tidal environments under a range of...
Subduction zone earthquake and tsunami hazards affect tens of millions worldwide and the recurrence of these disasters can be evaluated with paleoseismic techniques, because earthquake cycles (and their supercycles) typically span many millennia. In these three chapters, I discuss a suite of analyses I use to evaluate the sedimentary record...
Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to...
In this dissertation the interactions between hydrodynamics, sediment suspension and transport, and morphological evolution in the surf zone was investigated with a large-scale laboratory experiment data, CROss-Shore Sediment Transport Experiment (CROSSTEX). The data set included comprehensive measurements of water surface elevation, fluid velocity, sediment concentration, and morphology for irregular waves...
This research intends to provide insights into community wind energy development in Oregon using an integrated analysis approach, which incorporates GIS Suitability Analysis, Socio-Political Analysis, and Empirical Case Studies. In the GIS analysis, we developed a model through a series of steps (including data acquisition, preprocessing, data management, manipulation and...
The subaerial beach, composed of sand dunes and the foreshore, provides a natural buffer zone between vulnerable land and the dissipation of storm wave energy due to wave breaking. The natural beauty of this region is attractive to people, and as a result, significant investment has been placed in this...
Probability-based reliability methods have placed an increased emphasis on realistic simulation of structural behavior in bridge engineering. Uncertainty is present in every aspect of structural analysis. Aleatory uncertainties in the loading and load-carrying capacities, and epistemic uncertainties in mathematical idealization of bridge systems are the major contributors to uncertain structural...
Submerged aquatic vegetation (SAV) species, such as seagrasses, are highly valued in estuaries because of the many economic, ecological, and cultural services that they provide, including shelter for fisheries, minimizing water turbidity, and improving am-bient water quality. SAV can also alter its physical environment by attenuating wave and current velocities,...
Coastal communities in the U.S. Pacific Northwest (PNW) are rapidly engaging with the idea that hazards and environmental pressures are changing and may be characteristically different in the near future. This has led to a need for scientific knowledge and tools that can help coastal communities prepare and build resilience...
We examine the interactions and feedbacks between bathymetry, waves, currents, and
sediment transport. The first two pro jects focus on the use of remote sensing techniques
to expand our knowledge of the nearshore. Due to the plethora of snap-shot data that is
available from satellites and their distribution via Google...