Sediment and Hydraulic Characteristics of Palmer Inlet, Prince Edward Island, Canada

Abstract

<p>In order to study the sediment and hydraulic characteristics of a small tidal inlet on the coast of the Gulf of st. Lawrence, field measurements were conducted at Palmer Inlet in 1984-1987. Data collected included continuous water level and velocity measurements at various sites, bed and suspension sediment samples, box- and tubecores, direct and indirect (echo sounding) bedform observations, and general area mapping. Historic records and wind data were also available.</p> <p>The first part of the thesis presents results of analyses of field data. Inlet morphology is described and its migratory behaviour analyzed by series of airphotos and maps. Surface sediment is divided into five depositional environments. Their characteristics, including grain size, bedforms and internal structures, are described based on the relative strength of tide and wave energy. Surface and subsurface data are then used to construct a three-dimensional stratigraphic model. Three sediment units were recognized, and discussed in terms of their relationship with the Holocene transgression. Generalized vertical sequences are compared with typical models, and their differences noted. Suspended sediments, megaripples and sediment transport data were also collected. Using these data, a number of existing theories and techniques are tested. They include the Rouse equation, proposed stability fields of megaripples, and their description using a variance spectrum.</p> <p>A series of numerical simulations was carried out in the second part of the thesis. Their purpose is to define the hydraulic mechanism that controls the bay tidal responses and related inlet currents. The effects of various factors were examined using idealized cases. The results show that in small tidal inlets, large intertidal sand bodies are the most important factor in distorting the tide and creating asymmetry. Overall, their presence imposes a force which retards the ebb more than the flood. The model, adjusted with measured data, is then applied to Palmer Inlet. Examples of model results are used to explain the observed tidal deformation. A stability analysis of the inlet was conducted using two existing methods, from which inlet evolution is inferred.</p>