Survey of Hydrological Drought and its Effects on Lenjan Agricultural Region

Drought phenomenon is one of the environmental hazards, having long been particularly considered as one of the 20th century scientific facts. This climate phenomenon is different than other phenomenon and hazards, due to its being crawling, continuous, inevitable, and having gradual effects. Our especial geographical location of Iran on the dry belt of Earth, especially our studied region, provides conditions for the occurrence of this phenomenon, more and more. This research has worked on checking and detecting hydrological drought in the Lenjan Township, using surface water supply index (SWSI), then, effects of this phenomenon on agriculture sections have been evaluated. Data Analysis Method is statistical relationship analysis. Results showed that in the study period (2001-2012), drought conditions with 42% occurrence probability in total, have the most occurrence probability. Estimation results of SWSI index for revealing area drought, show that, there have been only two normal years, and other years being in hydrological drought situations. The outcomes of the Mann-Kendall test in routing agricultural products changes, show that production level and acreage level of garden products have enjoyed a rising trend, while their operation rates have enjoyed decreasing trends. A decreasing trend is also yielded in production, acreage level, and operational performance of crop production in the area. Among all agricultural products, only rice has an increasing trend in production and acreage levels.