Broad Cove Elevations
Broad Cove Elevation Profiling
Water transports sediments of different sizes according to how much energy is associated with the flow. Faster flowing water can transport larger particles - in fact large boulders are moved by floods in rivers and by massive waves during storms on beaches. The Broad Cove Elevation Profiling Study is an attempt to examine the forces acting on the inter tidal environment by examining after the fact, the transport of particles of different sizes - from small gravel to large boulders - following winter storms. The study uses protocols previously established for examining sediments and profiles of a river bed. To measure changes in elevations over time, a baseline transect of a known location must be established. An accurate way to do this is by using laser levels that are part of the basic tools of surveyors. The laser level is placed at a known height in this case by using U.S. Geological Survey pins of known height. The laser level projects a laser beam in a level plane on that elevation. Then, a measuring rod with a sensor is raised until it is in line with the laser beam. A measurement is then read from the rod, and the current height below the laser level is known. By doing this at multiple points along a transect, the experimenter can determine a basic profile of the bed of the riverbed or the profile of an intertidal transect. Sean Griffin Reestablishing Transect Locations 2007 Photo by Marie Fleury This study examines Broad Cove on Appledore Island at the Shoals Marine Laboratory as part of the Ocean Science course of 2006 and 2007. The survey reports two longitudal profiles on the north and south edges of Broad Cove running from 50 feet above mean high tide to 50 feet below mean low tide. Cross sectional profiles of the cove were also taken one on the west end of the cove above mean high tide and one approximately at mean low tide. The study also reports four pebble counts. A pebble count looks at sizes of particles, i.e. randomly picked rocks along a transect measuring how big they are. This tells us the general distribution of the particle sizes in the cove, and therefore where the largest general wave energy is.