Prediction of the Future Situation of Water and Improving its Agricultural Productivity in the Upper Part of Orontes Basin.

The climatic fluctuations impact on the hydrological system, population growth, and social and economical development has into resulted increasing pressure on water resources. Therefore, it is necessary to develop a prediction model that contributes to the estimations of future water resources of the Upper Orontes basin whereas 2010 as the base year. In this paper, solutions have been reached to make a substantially optimum use of the limited water supply in agriculture.Although the target is clear, the means are still not clear, in particular.The lack of knowledge of how water is used and depleted within irrigation projects. This has led to the water balance at field, irrigation service and sub basin levels by using the Water Evaluation and Planning Software (WEAP-MABIA). This research estimated water resources in the basin, analyzed time series of the data using the Box-Jenkins method and chose the seasonal Autoregressive Integrated Moving Average and statistical distributions that are appropriate for available data. It also identified the water needs andpriorities of the various sectors and the ways to provide them. Three scenarios were evaluated depending on the actual situation (RF), the best available technology (BAT) and high technology (HT) through two cases of climate fluctuations (the dry years and very dry years). The results are visualized as graphs, maps and tables (water balance, water deficit, water productivity, etc.) and showed that by application of high available technology scenario at the sub basin level and irrigation scheduling at the field level, it can avoid the water deficiency in the first case of climate fluctuations and promoteagricultural water productivity better than farmer’s method in the target area. The second case,on the other hand, will require special water conservation efforts at all levels, such as the optimum use of Zeita dam to cover domestic use needs and the use of groundwater for irrigation purposes only. This will help in minimizing the gap between supply and demand till 2050. Thus the developed model results have been proved to be a user-friendly, inexpensive and efficient tool for water resources management.