Physical Sciences and Mathematics Commons^™

Enewetak (Eniwetok) Atoll- Aspects Of Nitrogen Cycle On A Coral Reef, K. L. Webb, William D. Dupaul, W. Wiebe, W. Sottile, R. E. Johannes

VIMS Articles

No abstract provided.

Tidal Discharge Asymmetry In A Salt Marsh Drainage System, John D. Boon

VIMS Articles

Tidal discharge and area‐averaged current speed were measured over complete tidal cycles at the entrance to a salt marsh drainage system near Wachapreague, Virginia. A pronounced asymmetry in curves of discharge and current speed through time was observed which can be simulated by a model incorporating semidiurnal tides and “overtides” in conjunction with marsh and channel storage relationships. As a persistent feature in marsh channel flow relationships, the asymmetry, along with an apparent difference in flood and ebb maxima, may have a systematic, long term influence on the net transport of suspended matter entering and leaving natural marshes.

Optimized Measurements Of Discharge And Suspended Sediment Transport In A Salt Marsh Drainage System, John D. Boon

VIMS Articles

Detailed measurements of current speed and suspended sedlment concentration distributions in a channel cross-section of a tidal marsh creek were analyzed. Subsequent sampiing Intervals In time and space were selected to provide acceptable estimates of flood and ebb transport of water and suspended sediment post the cross sectlon. Data from eight 13-hour measurement runs taken at various times of the year seem to favor a net ebb resldual of suspended sedlment transport for the year In question.

A number of environmental factors appear to Influence suspended sediment trons· port in marsh channels.Residual transport of sediment In these systems is, however, …

Groundwater Flow In A Sandy Tidal Beach 2. Two-Dimensional Finite Element Analysis., C. S. Fang, S. N. Wang, W. Harrison

VIMS Articles

Two-dimensional finite element techniques are described that model closely the complicated fluctuations osbserved in the water table of an ocean beach. The use of triangular elements permits the specification of more realistic boundary conditions than the use of line elements in a one-dimensional model. Also, results obtained from the two-dimensional model for the region closet o the ocean compare more favorably with field data than results obtained from the one-dimensional finite element model.

Groundwater Flow In A Sandy Tidal Beach 1. One-Dimensional Finite Element Analysis, W. Harrison, C. S. Fang, S. N. Wang

VIMS Articles

A 31-day time series of observations of beach water table and tidal fluctuations was obtained from 13 wells along a profile perpendicular to the shoreline at Virginia Beach, Virginia. Finite element techniques were applied to solve the one-dimensional, unsteady state, nonlinear equation for groundwater movement. For the finite element analysis, the semi-infinite mass (unconfined aquifer) had to be replaced by a finite mass. The boundary conditions were found from the field data by directly solving the flow equation with a finite difference technique. The finite element method, using the variational principle, provided a reasonable solution and afforded economy in computer …

Predictor Equations For Beach Processes And Responses, W. Harrison, N. A. Pore, D. R. Tuck Jr.

VIMS Articles

A stepwise (linear) multiple regression procedure is applied to 11 environmental variables (or predictors) in the beach-ocean-atmosphersey stema t Virginia Beach, Virginia, for the following five predictands: mean longshore current velocity, mean bottom slope in the shoaling-wave zone, average mean grain size in the shoaling-wave zone, and beach deposition and beach erosion on the lower foreshore. Predictors consist of variables related to beach geometry, local water properties, local wind conditions, tidal fluctuations, and wave characteristics The resultant equations are tested against a set of independent data and, with one exception, agree reasonably. It is believed that if the data set …

Possible Late Pleistocene Uplift, Chesapeake Bay Entrance, W. Harrison, Rj Malloy, Ga Rusnak, J Terasmae

VIMS Articles

Paleontological and lithological studies of engineering borings and boring logs subaerial erosion surface of Pliocene (?)-Pleistocene age cuts across clastic sediments of pre-Yorktownian Miocene age in the subsurface and subbottom of the lower Chesapeake Bay area. When the bore-hole data are coupled with the results of subbottom echo profiling and piledriving records, it is possible to construct accurate cross sections of the buried Miocene-Pleistocene contact. The cross sections show "lows" in the erosion surface that may be correlated with the buried channels of the Pleistocene Elizabeth, James, York, and Susquehanna river valleys. Probable channel depths below mean low water at …

Sea-Level And Crustal Movements Along The New England-Acadian Shore, 4,500-3,000 B.P, W. Harrison, C. J. Lyon

VIMS Articles

Remains of three drowned forests have been investigated at Odiorne Point, New Hampshire, and Fort Lawrence and Grand Pre, west-central Nova Scotia. Carbon-14 ages and altitudes below mean tide levels were determined for four in-place stumps of white pine at each locality. Assuming that each dated stump was killed by rising salt water, and that its C14 age represented its true age at death, it was possible to construct curves showing the sequence of submergence and emergence at each site.

A continuous transgression of the sea, approximating 0.31 foot per century, is indicated for the period 4,500-3,200 B.P. This rate …