A STUDY ON URBAN GROWTH IN TORRENT RISK AREAS IN ASWAN, EGYPT

Abstract

Many areas in the Aswan region are susceptible to floods and torrents that often cause loss of lives and severe damage to buildings and infrastructure. The hazardous situation is exacerbated by urban growth extending towards the risk areas. To ameliorate the danger, three key issues for urban growth management were studied, namely (i) estimation of the pace of urban sprawl (ii) identification of urban areas located in regions that would be affected by flash floods (iii) examining the characteristics of urban growth in high risk areas. Since official data and field data were limited, we used two free sources of satellite data. First, we simulated the occurrence of torrents and identified the risk areas using the GSSHA model in WMS. Second, we studied historical imagery of the area using Google Earth to examine changes in urban growth in 2001, 2005, 2009 and 2013. The results showed urbanization in risk areas to be 59.79 % in 2001, then rising to 65.45 % in 2013. Hence, our findings indicated that urban expansion in the risk area was greater than that in the safe area. The creation of a hazard contour map in Arc GIS using WMS data based on water depth enabled a better appraisal of the risk area. As the urban sprawl grew, so did the size of residence blocks. In the same context, it was observed that on average, residence blocks in the risk area were bigger than those in the safe area, and also bigger than those built in earlier years. The findings from this study would be useful to urban planners and government officials to make informed decisions on urban development to benefit the community, especially those living in risk areas from torrents.