Flood-Tide Deltaic Wetlands: Detection of Their Sequential Spatial Evolution
Qizhong Guo and Norbert P. Psuty
Photogrammetric Engineering & Remote Sensing, Vol. 63, No. 3, 1997, pp. 273-280
Abstract
Techniques to detect evolution of marsh islands in Great Egg Harbor Bay, New Jersey are presented in this paper. Aerial photographs and topographic maps were digitized. A geographic information system (GIS) was subsequently established with the digitized data. A computer program was also written to carry out necessary computations. Through these efforts, change in area shift of centroid, and rotation of marsh islands were quantified. It was revealed that (1) over the recent 51-year period (1940-1991), the aerial loss of the entire group of islands has amounted to slightly under 5 percent, and most individual islands have the same trends of decrease in area; (2) the centroid of the entire group of islands has shifted northeastward, 333 feet to the east and 202 feet to the north, but the trends of individual islands vary; and (3) the entire group of marsh islands has retained its general orientation through the period; however, some individual islands have rotated dramatically. These features of marsh island evolution are important to maintenance of navigation channels because they affect the width of channels between the islands and the spatial distribution of sedimentation. These features of marsh island evolution also need to be known for management of the coastal ecosystem because they are indicators of stability of biological habitats.
