Date of Award
Master of Science in Environmental Sciences
Natural Resources Science
Barrier islands are extremely dynamic landforms, and one of the most dynamic aspects of a barrier island is the beach. In an effort to document change in these environments, the National Park Service (NPS) Inventory & Monitoring Program Northeast Coast & Barrier Network (NCBN) have established a set of coastal geomorphology protocols to collect ecological indicator datasets. Two of the most important and readily available sources of data within these protocols are horizontal shoreline locations collected by global positioning systems (GPS), and general beach topography collected by lidar topographic surveys. There are several methods used to quantify the amount of change between these datasets. Shoreline change analysis, or measuring the amount of change in shoreline position over time, is a commons application of coastal geomorphology data. One of the most valuable opportunities provided by lidar surveys is the examination of overall beach topography in an accurate, efficient, and spatially dense manner.
For research and management personnel in National Parks that contain a barrier island depositional environment, these data and analyses are extremely useful for a variety of Park Service applications. In an effort to determine and document what data and analyses are available to park personnel, I led interviews and discussion groups at the four open ocean national Park sites in the NCBN. Some of the most common requests and interests involved an ease in visualizations of both shoreline and lidar datasets; shoreline change analysis on either shoreline, or a specific user-defined segment of shoreline; determining areas with significant changes in elevation using lidar surveys; and highlighting specific elevation ranges.
Through these discussions, it became apparent that managers and researchers within the Park Service are interested in using shoreline and lidar data, but many do not have the time or experience required to efficiently do so. As a solution to this problem, I have created the Coastal GeoToolbox. This is a GIS-based set of automated procedures, with the intention of simplifying the utilization of shoreline and lidar data. The Toolbox was created using the Visual Basic for Applications (VBA) programming language, and ArcGIS 8.3. The tools included in the Coastal GeoToolbox are: a graphical user interface (GUI) drive definition query for the NCBN shoreline databases; automated shoreline change analysis; creation of a standardized lidar legend; ability to extract elevation data for other GIS datasets; simplification of some Spatial Analyst functions including creating contour lines slope maps from lidar data; calculate changes in lidar surveys through topographic change analysis; highlight specific elevation ranges; and extract a smaller portion of the lidar survey. The ocean parks in the NCBN will all receive a copy of the Coastal GeoToolbox along with a User’s Manual and sample datasets.
The Coastal Geo Toolbox was then utilized on an application relevant to the National Park Service as an evaluation of the efficiency and accuracy of the toolbox. The application chosen was to examine the geomorphologic effects of adding fill in the form of a complex replenishment template to the Northend region of Assateague Island National Seashore in the fall of 1998. This template included adding sediment to the berm and back-barrier flat, as well as the construction of a foredune. The Coastal Geo Toolbox was used to examine any effects the fill may have had on shoreline change and overwash. Control areas were chosen in the adjacent areas to the north and south of the fill area. My hypotheses were that the fill had created a more reflective beach profile, which would cause an increase in shoreline erosion, and that the higher elevations in the fill area would restrict overwash over the island. The results of these analyses showed that the only difference in shoreline change between the control and experimental sites was a greater amount of shoreline accretion in the fill area, probably due to the fill spreading out onto the berm and beachface. Visual examination of the lidar surveys showed some possible overwash restriction in the fill area, but quantitative analysis through volume calculations seemed to be impacted by the quality of each lidar survey. Overall, the Coastal GeoToolbox provided the necessary analysis and visualization procedures to undertake this comparison in an accurate and efficient manner.
Rodriguez, Arthur, "Needs Assessment, Creation, and Utilization of the Coastal Geotoolbox" (2004). Open Access Master's Theses. Paper 2064.