IWRA Proceedings

AbstractThe Government of Iran (GoI) is pursuing a policy of modernisation and expansion of irrigated area with objective to assure an increase of agricultural production and farmers’ incomes. This development has as side effect that scarce water resources are increasingly strained. In traditionally irrigated areas farmers, who are used to a little and unreliable water supply, tend to over supply water to crops in modern irrigation schemes limiting potential area that can be brought under irrigation and leading to an increasing extension of areas affected by waterlogging and salinity. The Lake Uromiyeh Basin (51,000 km2) is located in Northwest of Iran. It is a classic closed drainage basin. Economy of the basin is strongly dependent on agriculture. The Lake is one of the most important and valuable aquatic ecosystems in Iran. It has been declared a National Park, Ramsar site and UNESCO Biosphere Reserve. During the last two decades, pressures on natural resources of the Lake have grown as a result of non-sustainable human activities (agricultural intensification, water resources developments). As a result, the ecosystem has been severely degraded, such that its capacity to deliver social, economic and environmental benefits is under real threat. Future of agriculture and of the Lake Uromiyeh National Park is under severe threat because of increasing water abstractions for irrigation. There is an urgent need to raise awareness of the ecosystem problems, to improve the low irrigation efficiencies (35%), and to enhance farmers' participation in water management. The GoI has formulated a policy for control of overuse of water. The policy is expected to provide incentives to farmers to reduce water-use. Implementation of the policy will require cooperation and acceptance of farmers, who will have to adjust their traditional irrigation practises. Several studies, including Pilot Water Management Studies (PWMS), have been carried out in the area with objective to determine with which irrigation methodologies and management practices water use can be reduced while assuring similar or increased yields. Outcome of studies forms basis of guidelines for reduced water use on on-farm level. In order to assure that resulting guidelines are realistic and can be implemented by farmers, studies have been carried out in a participatory way in a farmer’s environment. Studies have been conducted on dominant crop, sugarbeet, in Naghadeh and Mahabad plains in the Basin. Results show that upon improvement of on-farm water management practices 62-70% less water would be used, while 14-29% higher yields are achieved. As a result application and water use efficiencies would be increased by 43-67% and 74-79%, respectively. There is about 335500 hectares of lands throughout the Basin under irrigated agriculture. Supposing a minimum sound value of 2500 m3/ha of water saving in a cropping year through efficiency improvement roughly 839 MCM water would be potentially saved. It would easily be concluded that finding and employing improved on-farm irrigation water management practices would result in considerable impacts on agricultural water demand in the area, providing ample scope for co-existence of agricultural and environmental demands for water in the basin.