Urban Sprawl Impact Assessment on the Fertile Agricultural Land of Egypt Using Remote Sensing and Digital Soil Database, Case study: Qalubiya Governorate Shalaby, A. & Gad, A. National Authority for Remote Sensing and Space Sciences, Egypt

Urban sprawl is one of the main problems that threaten the limited highly fertile land in the Nile Delta of Egypt. In this research, satellite images Landsat TM 1993, ETM+ 2001 and Egypt Sat-1, 2009 has been used to study the urban sprawl and its impact on agricultural land in Qalubiya Governorate. Maximum likelihood supervised classification and post-classification change detection techniques were applied to map land cover changes in the study area. Collected ground truth, during several field trips conducted between 2003 and 2008, and topographic map of 1991 were used to assess the accuracy of the classification results. Using ancillary data, visual interpretation and expert knowledge of the area through GIS further refined the classification results. Postclassification change detection technique was performed to produce change image through cross-tabulation. Combining the soil and land capability maps, in one hand, and the urban thematic layers, in another hand, using GIS, made it possible to point out the risk of urban expansion on the expense of the highly capability soil class. During the study period, the high capable soils (Class I) decreased from 683.2 to 618.5 Km. The moderate capable soils decreased from 100.5 to 93.8 Km, while the marginally capable soils decreased from 209.1 Km to 198.3 Km during the same period. It is noticed that urban encroachment over the non capable soils are very limited, as their coverage was found stable during the period 1993 – 2009.