Managing the increasing water demands in Egypt, with limited water resources, urges Egypt to find innovative and sustainable approaches for management, and to make use of the information technologies to build computerized decision support systems. The development of open-source GIS and DSS was best fit for modeling, monitoring, and estimating agriculture water demands, which is more than 80% of water demands in Egypt. The developed DSS can Compute the water consumption of different scenarios for cropping pattern, based on different objectives, and taking into account the fluctuation in the...