5 Conclusions
A comprehensive assessment of all input and output parameters affecting water resources in the watershed revealed an inconsistency between them. The analysis indicated that a total of 336.14 million cubic meters of water was consumed over 16 years, and it was evident that population growth and development in industry did not contribute to this significant consumption. Thereby the only plausible explanation for this high level of water usage was the agriculture sector. After making certain assumptions, we estimated that the development of sprinkler irrigation systems in the study area has caused a significant water withdrawal and wastage of resources in the form of wind drift and evaporation losses upstream of Eskandari station. This estimation was consistent with the total decrease in flow volume based on aquifer storage decrease, up to Eskandari station and the positive trend of the Cheshmeh-Langan tunnel.
The sprinkler irrigation system's excessive development in recent decades has caused a severe strain on the region's water resources. While measures to tackle these issues, such as reducing water consumption, purifying and reusing wastewater, and using any available water, seem straightforward, the most effective solution in this region upstream of the Zayandeh-Rud River lies in gradually replacing the sprinkler irrigation system with greenhouses. The construction of greenhouses effectively eliminates wind drifts and evaporation losses caused by sprinkler irrigation systems, returning lost water to the system. Although this plan may face resistance from farmers in the region, the government should implement a comprehensive strategy to persuade them. This strategy should focus on raising awareness of the importance of water conservation and creating a culture of water-saving practices. Additionally, the government should provide financial incentives such as zero-interest loans, and tax breaks to farmers who install greenhouse irrigation; the government should also create market access for greenhouse-grown produce to help farmers recoup their investment.
Furthermore, the taken measures should also consider reducing the pressure on aquifers. Therefore, we recommend encouraging farmers to utilize surface irrigation. This traditional irrigation method is more sustainable than sprinkler irrigation, as it can help to conserve water and, more importantly, play a crucial role in replenishing aquifers. By collectively adopting these measures, the water scarcity issue in the Eskandari watershed which requires immediate attention can be effectively addressed and ensure sustainable water management for future generations.