Assateague Island is a barrier island subject to forces that dynamically alter the physical and biotic properties of the island. Storms are a major driver of change, causing shoreline erosion and often shaping interior island characteristics through overwash events. Tropical Storm Ernesto impacted Assateague Island on 1-2 September and the island overwashed in several locations. Ernesto was a tropical depression at this time, but interacted with a high pressure system, producing hgih winds and waves. This dataset contains elevations of overwash areas on the northend of Assateague Island shortly after Ernesto passed. Horizontal and vertical position was determined with a Trimble 5700 RTK GPS total station on 7 September 2006.
The purpose of this data set is to show the effects of overwash on the island and how rapidly this can reshape the shore. The dynamic nature of coastal barriers such as Assateague Island is a defining characteristic, influencing nearly every aspect of their ecology. Fundamentally disturbance driven systems, barrier islands and their endemic biota are continually shaped by physical forces on a time scale vastly accelerated in comparison to mainland systems. Because of the rapid pace and scope of change, long term monitoring is crucial towards understanding natural barrier island conditions as well as anthropogenic influences.
ground condition
None
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Arty Rodriguez
Attributes are accurate as recorded and as reported after processing in Trimble Geomatics Office.
Topology is consistent and clean.
The data set is complete for overwash areas of interest. Other overwash areas occurred on Assateague Island during this storm, however all overwash areas were not surveyed. All overwash areas on and in the vicinity of the constructed storm berm were surveyed.
<= 0.15 m
<= 0.20 m
Areas of overwash were surveyed when weather and ground conditions became favourable. A Trimble RTK 5700 GPS total station was used to record horizontal and vertical position. The base station, with a Trimble Zephyr Geodetic antenna and Trimmark III radio was setup on GPS 3 (immediately north of the constructed storm berm). The rover receiver was a Trimble 5700 receiver with Zephyr antenna. A west to east profile with a point taken every 5 seconds or at breaks in slope was surveyed through each overwash area. A north to south profile was surveyed through each overwash fan using the same point interval. One significant overwash area through the constructed storm berm was surveyed in a grid so as to produce a surface. A point was shot every 5 seconds.
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Data was imported into Trimble Geomatics Office. Attributes and positional information was checked for accuraccy and completeness. Data and attributes were exported as a .txt file.
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Data was converted to a shapefile in ArcCatalog.
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Dataset copied.
Feature geometry.
ESRI
time feature collection began
ASIS
point name
description of noteworthy points
feature code recorded in field
Northing
Easting
Elevation
Year
Internal feature number.
ESRI
Month
Day
Latitude
Longitude
Height above ellipsoid
Root Mean Square
Minimum Number of Sattellites during observation
Horizontal Precision
Vertical Precision
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