فهرست مطالب zarafshan salari

Coastal zones are one of the most sensitive areas with the constant changes due to their dynamic nature. They are also precious zones in terms of fisheries, transportation, recreational activities, and other rich resources. Thus, any changes in such areas can influence all such activities. Natural disasters are one of the main concerns in sensitive areas such as coastal zones. Due to its sensitivities, these areas may be affected significantly by such disasters. Coastal zone management (CZM) mechanism is a proper choice, which is applied and implemented with the aim of ensuring the sustainability of resources and these environment. In the operational and research framework of CZM, natural phenomenon and disasters are considered and their affects are surveyed for best managements of the area. Large-scale natural phenomena such as earthquakes or groundwater depletion due to climate change in coastal low-lying areas cause various types of instability. On the 2nd of July 2022, three strong and consecutive earthquakes occurred in the coastal area of Sayekhosh, Located 123 km from Bandar Abbas city and 70 km from Bandar Lengeh city (South of Iran). As a result of these earthquakes, the Sayekhosh Shrimp farm center was seriously damaged. In this study, using RS and GIS techniques, the impact of these earthquakes on the coastal area has been investigated. Using the data of the SAR images from Sentinel-1 satellite and applying the DInSAR technique, a coherence map, differential interferograms and vertical changes map of the region have been produced, which are used to determine the uplift or subsidence of the land's surface. By using the data of Sentinel-2, Landsat-5, and Landsat-8 satellites and using the band ratio technique, the conditions of the farm ponds and the shoreline of the region were determined. Using the Normalized Difference Water Index (NDWI) (with Green and NIR bands) and applying unsupervised K-means classification, two water and land features have been separated. These were done using ENVI, SNAP and ArcMap software. The surface of the area in the northwestern part of the farm has changed in the form of uplift (up to 0.2 m) and in the eastern part of the farm along the coast in the form of subsidence (up to -0.1 m). Band ratio results showed that after five days of the earthquakes, 189 ponds were discharged. Besides; we detected about -30 m shoreline transformation in the areas close to the farm canals and river mouths due to the earthquakes. The results showed that the location and/or the establishment of traditional shrimp farming system should be reconsider, to avoid such damages in upcoming disasters. Since natural disasters strongly affects man-made structures especially in the coastal area, the use of satellite data and RS and GIS techniques can be useful to precisely monitor and manage the changes in the coastal area.

Nearshore is dynamic and constantly affected by the environmental conditions of the sea, on the other hand, it plays a great role in economic-social management issues. The shoreline is also a part of the nearshore that is constantly affected by tide, waves, currents and human activities. Therefore, it is expected that this section will always be accompanied by changes. The first step of any nearshore development and construction is to know the hydrodynamic conditions of the area. In this study, an attempt has been made to investigate the sensitivity of the shoreline of Bandar Lengeh County by considering the height and energy of nearshore waves. Wave height and energy data have been estimated by running the MIKE 21 spectral wave numerical model for a period of 12 months. The results have been obtained with good accuracy compared to ECMWF data. The correlation coefficient and the RMSE are equal to 0.95 and 0.239. The modeling results show that the maximum average height and energy of waves in the shoreline are 0.22 m and 0.21 kW/m, respectively, in the last months of spring and the beginning of summer. Using the fuzzy-gamma logic and considering the gamma coefficient as 0.9, shoreline sensitivity to variables has been estimated and finally divided into three classes High, moderate, and low. 20% of the shoreline is in the high class, and 23% and 57% of the shoreline are in the moderate and low class, respectively.

Estuaries are transition zones between the sea and land, and are constantly affected by tides. These areas are biologically important and sensitive. Tiab estuary, 7 km from away from the coast of Strait of Hormuz, is covered with mangroves and is also used for navigation by small commercial boats. This estuary is facing sedimentation issues nowadays which troubled navigation of vessels. Since the local wind conditions of the area is different seasonally, the influence of this difference on the transformation of the shoreline is considered for the years 2019 and 2020. The wind direction in the area is mainly SSW during summer, while is totally diverse during winter. Sentinel-2 satellite images have been used with similar water-level conditions. Normalized Difference Water Index and K-means algorithm are used for shoreline detection. The results show that the area of the estuary is more than 10 hectares smaller in summertime than in wintertime. The correlation coefficient of the seasonal transformation of the shoreline in 2019 and 2020 is 0.84, which shows that the seasonal transformation was similar in the two years. Shoreline transformation was at most along the curvatures of the river, whether in upstream or downstream. It was however varied between 45 and 200m. Some dissimilarity in shoreline transformation was detected between the two years of study, specifically in upstream of the river, which is suggested to be due to human activities. It is believed that those parts of the estuary with high transformation are subject to permanent transformation in long term.