Evaluating urban expansion using remotely-sensed data in Lebanon

Over the last decades, continuous urban expansion at rates much higher than population growth has resulted in a massive urban footprint all over the world. In Lebanon, a civil war in the mid 70's has resulted in a low density and fragmented urban sprawl. Nearly after 1990, when the declaration of Taaef ended the Lebanese war, a major reconstruction and reforms have taken place. This peaceful atmosphere launched a massive construction of roads and buildings, water and sanitation filcilities, and energy and transport systems, which transformed eternally land cover and cities of Lebanon. This study aims to follow the evolution of urbanization from 1963 till 2005 in Lebanese major cities by processing and interpreting topographical maps and satellite images acquired by different space platforms. One examines urban growth trends in Lebanon between different years and provide a characterization of Lebanese urban development per governorate and per district. Also, we inspect urban agglomeration in Greater Beirut Area [GBA], which is the main urban center in the country, as well as seven major Lebanese cities [i.e. Tripoli, Zahle, Saida, Tyre, Baalbek, Nabatiye and Jounieh]. Some cities show a positive trend [e.g. Zahle illustrates a urban expansion from 3 percent of its district region in 1963 to 10 percent in 2005, Tripoli grows from 20 to 56 percent of the district in 2005, etc.]. While Nabatiye, and South Lebanon region in general, reveal a high rate of urbanization, a weak rate of urban expansion is shown particularly in North Lebanon. Political favoritism is one of the main reason to blame. Anyhow, the adequacy of the remote sensing in evaluating urbanism is proven again, particularly in unstable countries and regions. This research intends to provide policy makers in Lebanon an essential decision tool, given the absence of a comprehensive population survey, to build and support sustainable urban planning

Assessing soil degradation by landuse-cover change in Coastal Lebanon

Change in landuse is rapid in Lebanon straining its narrow coastal strip. Chaotic urban expansion in the last forty years resulted in consumption of prime soils and degradation of most productive lands. This study aims to show such expansion in Tripoli, the country's second largest city of 61.5 km[2], and to evaluate the impact of landuse change on soil sealing and degradation by integrating remote sensing and GIS techniques. It will gear to more optimal landuse planning based on assessing the result of chaotic landuse change. Social and economic soil functions were involved and soil capability and land suitability compared. Quantifying land cover/use change in the pilot area was arrived at through analysis of multitemporal sources using airborne-based detailed topographic maps [1:20000 scale] from 1962 and satellite imagery IRS-1C, 5-meter resolution from 2000. The topographic maps contain detailed information on land use, like agriculture and type of forest with corresponding borderlines, urban areas with real geometric shapes and other info. This allowed identifying and grouping the data and comparison with that gathered from the high-resolution satellite images.The resultant change showed an increase of 208% of urban area with a decrease of 35% in agricultural lands. Secondary forest and shrubs replaced the orchards on the abandoned lands. Concerning land capability, 32% of class 1 [prime land] and 26% of class 2 land, i.e. 971 ha, were converted into urban area. Obviously, urban expansion occurred at the expense of rare fertile soils with citrus orchards of the coastal plain like Fluvisols, Luvisols and Cambisols belonging to the most productive agricultural land. Major structural changes in landuse between 1962 and 2000 occurred in the agricultural and urban sectors. Analyzing current landuse pattern, in view of requirements for sustainability, shows that about 10% of prime lands were properly used. Overall, only 22.6% of land is fairly used, while 46% is poorly used and 31.4% is misused. Providing a proper management of water resources, the geographically isolated southeast area with productive lands currently allocated for low-income olive monoculture could be used for more balanced agricultural production. Water harvesting and management will also provide adequate irrigation water for perurban agriculture