Remote sensing application to the management of agricultural drainage water in severely arid region: A case study

Abstract

Al-Hassa Irrigation and Drainage Project, with an irrigated area of 7096 ha, is one of the main agricultural areas in Saudi Arabia. About 111 × 10 6 m 3/ year of agricultural drainage water is collected by 1641 km of earthen drainage network and during winter it is mostly discharged into two evaporation lakes located outside the project area. Landsat data were used to map the monthly and seasonal changes in the boundaries of the lakes and the drainage canals in the sand dune areas. Landsat images for Al-Hassa Oasis during summer and winter months between 1972 and 1987 were produced from Landsat Multispectral Scanner and Thematic Mapper data. The images show that the drainage water has formed large water courses in the sand dunes and is being wasted by flowing into the Arabian Gulf during winter season. They also show that the water ceases to flow into the Gulf, and that the water courses dry up during the summer. This information is new, and has changed the previous concept that used to indicate that the drainage water remains in the lakes for the purpose of aquifer recharge and cattle drinking. These findings are very important and valuable in developing new plans for drainage water management and utilization in the oasis. It was found feasible to store 75% of the drainage water in two large semiburied surface reservoirs in the sites of the two lakes lined and covered with flexible membrane material. The stored drainage water can be used to satisfy the water shortages and to irrigate new areas during summer.