A key goal of tsunami research is to quantitatively reconstruct flow parameters from paleotsunami deposits in order to better understand the geohazards of coastal areas. These reconstructions rely on grain-size and thickness measurements of tsunami deposits, combined with simple models that allow an inversion from deposit characteristics to wave characteristics. I conducted flume experiments to produce a data set that can be used to evaluate inversion models for tsunami deposition under controlled boundary conditions. Key variables in the flume experiments are sediment grain-size distribution, flow velocity and depth, and depth of water ponded in the flume before the tsunami bore was released. Physical experiments were run in a 32 m-long outdoor flume at The University of Texas at Austin. The flume has a head box with a specialized mechanical lift gate that allows instantaneous release of water to create a bore. Various sediment mixtures (silt to very coarse sand) are introduced to the upstream end of the channel as a low dune positioned just below the lift gate. The bore entrained the sediment mixture, producing an unambiguous suspension-dominated deposit in the downstream half of the channel. Deposits were sampled for grain-size and thickness trends. The experimental results capture characteristics of many recent and paleotsunami deposits, including consistent fining in the transport direction. In addition to overall fining, trends in deposit sorting and coarse (D95) and fine (D10) fractions reveal the importance of sediment-source grain-size distribution on tsunami deposit attributes. / text

<p> The concern about the preservation of a valuable natural resource such as Point Pelee is readily apparent, yet along with this concern is the need for raw materials such as aggregates dredged from submarine sand and gravel deposits. This could involve a conflict in resource management, therefore the question of how significant commercial dredging is as a process element in the local coastal dynamics needs to be resolved. To provide a basis for this assessment, offshore and onshore surveys, bottom sediment analyses, wind-wave analyses, and current measurements have bee·n taken over the last two years to derive a sediment budget for the Point Pelee spit and shoal system. </p> <p> The magnitude of response was measured by the morphologic and volumetric variation between successive profiles at 18 sites throughout Point Pelee. The beach zone of the east shore evidenced the most dramatic morphologic and volumetric changes to its profile, with an average loss of 17.5 m3/m from fall to spring of 1975. </p> <p> Maximum material restored to the east beach in 197-5 was 4.5 m3/m. In terms of annual.quantitative changes to the beach budget, the westward migration of the Point is five times greater for the east shore than for the west. The sediment budget for 1974-75 shows a net deposition to the south of Point Pelee on the order of 440,000 m3. </p> / Thesis / Bachelor of Arts (BA)

A key goal of tsunami research is to quantitatively reconstruct flow parameters from paleotsunami deposits in order to better understand the geohazards of coastal areas. These reconstructions rely on grain-size and thickness measurements of tsunami deposits, combined with simple models that allow an inversion from deposit characteristics to wave characteristics. I conducted flume experiments to produce a data set that can be used to evaluate inversion models for tsunami deposition under controlled boundary conditions. Key variables in the flume experiments are sediment grain-size distribution, flow velocity and depth, and depth of water ponded in the flume before the tsunami bore was released. Physical experiments were run in a 32 m-long outdoor flume at The University of Texas at Austin. The flume has a head box with a specialized mechanical lift gate that allows instantaneous release of water to create a bore. Various sediment mixtures (silt to very coarse sand) are introduced to the upstream end of the channel as a low dune positioned just below the lift gate. The bore entrained the sediment mixture, producing an unambiguous suspension-dominated deposit in the downstream half of the channel. Deposits were sampled for grain-size and thickness trends. The experimental results capture characteristics of many recent and paleotsunami deposits, including consistent fining in the transport direction. In addition to overall fining, trends in deposit sorting and coarse (D95) and fine (D10) fractions reveal the importance of sediment-source grain-size distribution on tsunami deposit attributes. / text

Living shorelines are designed to address coastal erosion and their use is encouraged over that of hard structures such as sea walls and bulkheads because they provide habitat, improve water quality and stabilize shorelines. Objectives of this study were to: (i) Compare soil Nitrogen [N], Phosphorus [P], Organic Carbon [OC], organic matter (SOM) and soil bulk density between living, hardened and natural shoreline to determine if soil present within living shorelines is comprised of higher SOM and lower bulk density, that encourage marsh growth, as compared to hardened shorelines. (ii) Use an experimental mesocosm to test the effect of shoreline substrate types (living vs hardened vs natural) and nitrogen loading (at four concentration 0, 12, 24, 36 ml) on the growth of Spartina alterniflora. No previous study has documented the growth of Spartina in response to inorganic N loading at various shoreline substrate types. My results show living shoreline has significantly lower soil bulk density [F 2, 138 = 10.79, p <0.01] and higher SOM content than hardened shoreline [F 2, 138 = 10.26, p <0.01]. Combinations of N addition decreased plant’s root-shoot ratio and resulted in increased dry shoot weight. These results indicate that living shoreline is capable of trapping sediments within the nearshore environment, contributing to vertical marsh accretion by accumulation of organic matter, in the face of sea level rise. Findings from this research provide insights to local government, planners, developers and consultants on the benefits of living shoreline structures for the purpose of best shoreline management practice.