Change detection of Gaza coastal zone using GIS and remote sensing techniques

Gaza’ coastal zone suffers from permanent erosion as a result of the anthropogenic intervention. This study aims to assess and map land-use / land cover and shoreline changes in Gaza coastal zone using remote sensing and GIS tools as a step towards implementing coastal zone management. In addition, bathymetric map will be extracted using Landsat-8 image. Firstly, land-use / land cover change detection was carried out using SPOT-5, Landsat and Quick Bird for the years 2004, 2009 and 2016. Six classes were assigned to the study area using maximum supervised classification to investigate the evolution during past period. Secondly, change detection along the shoreline was implemented over the past 42 years from 1972 to 2014. Finally, the ratio transform technique was applied to the newly acquired multi-spectral image to extract the nearshore bathymetric map of the coastal area. Results of change detection revealed that coastal area was significantly changed: urban/built-up and agricultural area expanded, whereas area of bare land / sand shrank by 14,52 km2. In addition, shoreline analysis showed that, northern regions were substantially eroded by 186,15,103 m2 in the period 1998–2007. Moreover, an accretion occurred at the southern beach of Gaza's fishing port with a rate of 9,53,103 m2/year during the period 2007–2014. Ultimately, it is concluded that ratio transform algorithm used to extract bathymetry could retrieve depths from -25 m to -30 m. In addition, the result shows a good correlation between the estimated algorithm depths and the observed depths.