Analysis of Effect of the Climate Parameters Change on Runoff and Evapotranspiration of Mehrgerd Watershed

ng countries on one hand, and the need to provide food for this population, on the other hand, have not been the result of overreaching of resources. In this manner, the continuation of an untapped harvest of resources will endanger the sustainability of the region in the near future. Food production is largely depending on the water so that 70 to 80 percent of the water extracted from resources is consumed for irrigation, which is the reason why irrigated cultivation is regarded as inefficient consumers. Understanding how to extract, manage and consume water is the key to solve this problem. On the other hand, the health and safety of communities and agricultural production require energy. Principally in irrigation, it is not possible to extract water without consuming energy. Seeking to establish the goals of the third millennium of the United Nations, researchers have presented a variety of interdisciplinary approaches to achieve a dynamic balance in the food production and consumption of resources, most notably the approach of Water, Energy and Food (WEF) Nexus. Considering the limitation of the resources which is increasing day by day. This approach causes productivity increase by integrating water, energy and food cycles. Managing water, energy and food, despite the inherent systemic differences, are very similar, due to the close relationship between the system perspective and their interaction with each other, a new concept is now called a Nexus approach. This viewpoint describes the interconnected nature and the interplay of the three sectors.

This research was carried out in Sefid-Rud dam Irrigation and Drainage Network. Sefid-Rud basin is located in the Guilan province, which is benefits from high precipitation, but factors such as dams construction in the upper reaches of the Sefid-Rud dam, the timely inconvenient precipitation and the lack of infrastructure to harvest the runoff, causes water shortages in the area. It is worth mentioning that 50% of the Guilan households have engaged in rice cultivation and more than 70% of the lands are located in the irrigation and drainage network of the Sefid-Rud dam. Hence, reducing rice cultivation in this region will have a great impact on economic and social life. Managing a Nexus approach to provide WEF security requires integrated and analytical approaches that can identify cross-sectoral exchanges, cost-effective planning, policy, and strategy management. Therefore, in this study, WEAP and LEAP software were used for managing water and food resources and managing the energy sector in Sefid-Rud irrigation and drainage network, respectively. Then, the integrated water resources management in the area was addressed by establishing a linkage between these two applications. In the first part of this study, the parameters output such as net water demand, water resources share for each demand node, unmet demand and the coverage regardless of the energy sector were compared.

The results reveal that the annual water requirement of the Sefid-Rud irrigation and drainage network in 2016 with the NEXUS approach estimated about 8 million cubic meters more than the nonNEXUS approach. Agriculture is the most water-consuming node in the region and there are lots of dependencies on rice cultivation as the most water-consuming crop in the Guilan region. The next step aims to balance the supply and demand, the unmet demand at the agricultural section in the Foomanat, Central and East areas under various management scenarios. These scenarios are including dredging, increase the efficiency of transmission and distribution channels of irrigation and drainage networks, and eliminating unauthorized wells were evaluated.

By examining the results of the applied management scenarios mentioned above, the 30% increase in the efficiency of transmission and distribution channels of irrigation and drainage networks in SefidRud has the greatest impact on meeting the demand and reducing the unmet demands of triple areas. As a result of the 30% efficiency improvement scenario, decrease the agricultural demands of the Foomanat area, the central area, and the east (about 29.1, 84.5 and 62.1 million cubic meters, respectively) more than the reference scenario.