Dynamic conservation of traditional irrigation systems: a Falaj case study

Irrigation schemes depending on Aflaj, Qanats, Khariz, and Foggaras are found all over the world. In Oman, more than 3000 ancient Aflaj are still operated and managed the way they used to be a hundred years ago. Only a handful are currently automated for demonstration purposes. However, there has been no adoption of these automated systems by farmers due to the high cost of the investments and the collective decision of adoption that must be made by all farmers using the automated Falaj. This study explores the feasibility of installing a flow controller gate at the mother well to store excess water during rainy events and improve Falaj’s management. Falaj Tanuf was selected as a pilot, given the geological setting and availability of historical data. Time series analysis and a probabilistic simulation model were used to estimate the amount of water stored. The results showed that if 40% of the stored water is recovered, then supply and demand will balance in 95% of the years. The installation of a flow controller gate is thus very profitable; farmers will gain quietude as uncertainty due to water supply is mitigated. The flow controller gate might also help eliminate the night irrigation turn, enhancing the sustainability of agricultural activity in these ancient irrigation schemes.