A GIS Based Digital Land Resources Framework for Optimal Soil Management in Barda and Awaje Basin, Syria

Abstract

Barada and Awaje Basin is located in the southwest part of Syria and includes the capital of the country, the city of Damascus and its suburbs. It covers an area of approximately 8596 km 2 and constitutes a hydrologically closed basin. It has a far higher population density than any of the Syrian regions. The estimated population living within the borders of this region is more than 4 millions. Population growth in the study area causes competition on land resources between differ ent sectors and pressure on limited water resources. The national development plans aim to conserve arable lands, improve its productivity, and sustain the land and water resources. Therefore, providing accurate and integrated information about land resources is a must, especially with the accelerated progress of information technology. Such information would be the base for planning, decision making and research needs. Various available information and database systems were employed (e.g. ArcGIS, ERDAS IMAGINE and ENVI). Data of previous soil survey activities were the bases for the created GIS digital database. Soils survey maps (SCALE 1:100,000), were prepared as GIS ready maps. Urban settlements were updated using recent ETM+ and SPOT satellite images. An intensive field investigation was performed in the study region, with the purpose of representing the soil units and collecting ground control points and soil samples for laboratory analyses. The created digital land resources database was used to figure the distribution of soil units and to evaluate and map land suitability on the bases of FAO, 1985 [1]. It was found that the Aridsols soil order characterize most of the alluvial fan soils of Barada, while Inceptisols were found in the western plains and intermountain areas. The soil orders Entisols were found dominating the western mountain areas. The results showed that 28.6 % of the areas are classified as highly suitable for irrigated agricultural production, cor responding with Typic Haplocambids and Typic Haploxerepts soil sub-great group. The moderately suitable soils, exhibit 14.7 % of the areas. The marginally suitable soils represent 14.6 % of the areas. The not suitable soils dominate the soils of eastern lacustrine and desert deposits, representing 21.2 % of the areas. It could be pointed out that achieving such de