Physical Sciences and Mathematics Commons^™

Recurrent Flooding Study, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

Rivers & Coast is a periodic publication of the Center for Coastal Resources Management, Virginia Institute of Marine Science. The goal of Rivers & Coast is to keep readers well informed of current scientific understanding behind key environmental issues related to watershed rivers and coastal ecosystems of the Chesapeake Bay.

Impact Of Diatom-Diazotroph Associations On Carbon Export In The Amazon River Plume, Ly Yeung, Wm Berelsen, Et Al, Deborah K. Steinberg, Et Al

VIMS Articles

Offshore tropical river plumes are associated with areas of high N-2 fixation (diazotrophy) and biological carbon drawdown. Episodic blooms of the diatom Hemiaulus hauckii and its diazotrophic cyanobacterial symbiont Richelia intracellularis are believed to dominate that carbon drawdown, but the mechanism is not well understood. We report primary productivity associated with blooms of these diatom-diazotroph assemblages (DDAs) in the offshore plume of the Amazon River using simultaneous measurements of O-2/Ar ratios and the triple-isotope composition of dissolved O-2. In these blooms, we observe peaks in net community productivity, but relatively small changes in gross primary productivity, suggesting that DDA blooms …

Near-Synchronous And Delayed Initiation Of Long Run-Out Submarine Sediment Flows From A Record-Breaking River Flood, Offshore Taiwan, L. Carter, Jd Milliman, Pj Talling, R Gavey, Rb Wynn

VIMS Articles

Subsea fiber-optic telecommunication cables can break under fast sediment flows that travel 100s of kilometers through the deep ocean in response to earthquakes and submarine landslides. Similar flows are inferred to form from major river floods whose sediment-laden waters plunge and travel along the seabed. However, the complex initiation of flood-related flows and their hazard potential have not been observed until now. Here we use cable fault data from the Gaoping Canyon/Manila Trench off Taiwan to show that a major river flood, formed during Typhoon Morakot (2009), generated two, long run-out, destructive sediment flows; one during peak flood and the …

Poverty Shelf, New Zealand From The Holocene To Present: Stratigraphic Development And Event Layer Preservation In Response To Sediment Supply, Tectonics And Climate, Lila Eve Rose Pierce

Dissertations, Theses, and Masters Projects

The small, high sediment yield Waipaoa River is located on the tectonically active, mountainous Poverty Margin on the east coast of the North Island, New Zealand. In contrast to sedimentary sequences on passive margin shelves, active margins, such as the Poverty Margin, can preserve continuous records of changing geological and environmental conditions at the land-sea interface during rapid sea-level rise. Two subsiding mid-shelf basins on the Poverty Shelf contain thick transgressive sequences which provide a record of evolving river, climate, landscape, and oceanographic conditions since the Last Glacial Maximum (LGM). This dissertation investigates the stratigraphic development of Poverty Shelf, including …

Quantifying Watershed Loads To A Low Relief, Coastal Plain Estuary, The New River Estuary, N.C, Brittani J. Koroknay

Dissertations, Theses, and Masters Projects

Watershed modeling is an important tool for quantifying the inputs of fresh water, sediments, and nutrients into receiving estuaries and potential changes in those loads under scenarios including changes in land use and climate. There are a variety of existing watershed loading models available, from simple to complex, but a spectrum of these models have yet to be applied and compared in a low relief, coastal plain setting. This project has been conducted as part of the Defense Coastal/Estuarine Research Program (DCERP), which has focused on the impact of Marine Corp Base Camp Lejeune (MCBCL) and activities in the surrounding …

A Study Of Vertical Patterns And Mechanisms Of Along-Channel Estuarine Circulation, Qubin. Qin

Dissertations, Theses, and Masters Projects

The classical theory of estuarine dynamics has been challenged by a number of recent studies regarding the important contributions of tidal, lateral, and Coriolis effects to the subtidal dynamics at leading order. Although the classical theory excluded these processes, Hansen and Rattray’ ( R65) b subtidal circulation. However, the success of the predictive skill is not well understood. In this thesis, a perturbation approach is introduced to derive a “ ” (GS) of subtidal along-channel velocity profile for estuarine circulation incorporating the effects of tidal and lateral processes, which allows us to evaluate the possible circulation patterns, the underlying mechanisms, …

Relationships Among Fine Sediment Settling And Suspension, Bed Erodibility, And Particle Type In The York River Estuary, Virginia, Kelsey A. Fall

Dissertations, Theses, and Masters Projects

In order to understand the processes controlling the temporal variability in settling velocity (Ws) and bed erodibility (ε), in the middle reaches of the York River estuary, VA, the relationships between the hydrodynamics and particle types were investigated with a near-­‐bed Acoustic Doppler Velocimeter (ADV) and the York River 3-­‐D Hydrodynamic Cohesive Bed Model.

ADV observations of the flow characteristics that occurred over a strong temporal transition period indicated that Ws and ε were characterized by two distinct regimes with contrasting sediment and water column characteristics: (i) a physically-­‐dominated regime (Regime 1) which was a period dominated by flocculated muds …