Seyed Ramzan Mousavi and Jan Peter Muller
Department of Geomatic Engineering,
University College London,
Claudio Vita-Finzi
Department of Mineralogy,
Natural History Museum
David Price
Department of Earth Sciences,
University College London,
Fax: ++44 (20) 7380 0453
[email protected]
Abstract
This study focuses on applying remote sensing and GIS techniques to the monitoring and mapping of rapidly changing conditions in the wetlands regions of the Miankaleh Peninsula and Gorgan Bay at the southern Caspian Coast (Iran). Satellite data from the LANDSAT ETM, TM, SPOT, RADARSAT, some aerial Photographs and Space photographs have been analysed. SPOT-PAN data was georeferenced with respect to 1:50,000 topographic sheets in a Universal Transverse Mercator Projection and all the aforementioned data sets were then registered to this SPOT-PAN image. Change detection was performed manually by visual interpretation and updated features were digitised on screen.
Besides seeking to detect and quantify change, including the effects of coastal erosion, the study is designed to evaluate competing explanations for the rapid rise in the level of the Caspian Sea by 2.5 m between 1977 and 1996. The shoreline changes map shows that the Caspian Sea level rise affected along the coast Miankaleh peninsula and Gorgan Bay. Some areas were more vulnerable to erosion than others. Areas with extreme erosion are characterized by weak sediments. For instance, the west side of Gorgan Bay are characterized by weak Quaternary sediments, and the most vulnerable. The local population, in the moth of the Gorgan Bay due to high density fractures have had much destruction. The largest changes are shown on the SPOT image at the west side of the Gorgan Bay. The estimated change in shoreline over a 20 years period (1977-1997) in Gorgan Bay and Miankaleh peninsula is 200 – 19,240 meters. Thus the possible effects of gas and oil extraction in the last two decades will be modelled by analogy with other coastal gas and oil fields in order to discover whether the sea-level changes are the product of land deformation, minor climatic fluctuations or changes in industrial and agricultural water use. An attempt will also be made to apply InSAR methods using ERS1 and ERS2 tandem and differential data to the area for the detection of short-term coastal erosion. The ultimate aim is to identify the techniques, which are best suited to monitor change and plan disaster relief in the varied physical and economic environments to be found in Iran. The following brief conclusion results from this study:
- Georeferencing of SPOT, LANDSAT ETM, TM, RADARSAT and aerial Photographs using the georeferenced topography map help to compared rapidly and easily all of satellite data for different times and old aerial photographs GIS tools.
- By Processing of LANDSAT ETM created land cover changes map over study area that shows erosion is controlled by geology, geomorphology and regional and local fracture systems.
- RADARSAT image was useful to measure the shoreline changes, and map the structures, lithology and drainage systems in the Gorgan Bay area.
- Digital Elevation Model (DEM) is a good tool to interpreting geomorphologic features such as slope, fault type, and drainage characteristics around the Gorgan Bay area.
- The results of remote sensing and GIS methods made knowledge of historic changes and projection of future changes over study area that is useful tools in the management and regulation of coastal areas.
- The most sever coastal erosion occurs where the shoreline sediments were weakness especially western coasts.
