چکیده:
Drought is one of the natural disasters that periodically causes problems for human societies through negative effects on water resources and agriculture, and consequently, the economy of these societies. The aim of this article is to investigate the intensity of drought in the water year 1386-87 and its effects on water resources and agriculture in Marvdasht County. To conduct the research, precipitation data of Marvdasht County over a 20-year statistical period was used, as well as statistics on the output, input, and reservoir volume of the Doroodzan Dam, and the amount of agricultural crop yields, including wheat, barley, and rice per unit area. Drought intensity in this research was calculated using the Standardized Precipitation Index (SPI). The results of this research show that the drought in the water year 87 was of very high intensity and had severe negative effects on water resources and agriculture in Marvdasht County. Changes in groundwater levels and the inflow of the Doroodzan Dam have a time lag relative to changes in the SPI index. In the studied water year, due to the failure to meet the water needs of agricultural crops during the growth period, the yield of these crops per unit area decreased significantly compared to previous periods; for example, the wheat yield in Marvdasht County in the studied water year decreased by 38.3 percent compared to the previous year (1385-86).
خلاصه ماشینی:
To conduct this research, precipitation data of Marvdasht County over a 20-year statistical period was used, as well as statistics on the outflow, inflow, and reservoir volume of the Doroodzan Dam, and the yield of agricultural products including wheat, barley, and rice per unit area.
This research has been conducted to estimate the drought intensity of the water year 2007-2008 and to investigate the occurrence of meteorological, hydrological, and agricultural droughts in Marvdasht County for the studied time period.
(Refer to page image) Hydrological Drought Given the intensity and duration of the drought in the studied hydrological year, and the decrease in the rate of surface water infiltration into groundwater aquifers, the groundwater levels in the plains of Marvdasht County have experienced a severe decline.
(Refer to page image) The decrease in precipitation in the water year 1386-1387 and the occurrence of severe drought during this period led to a decline in groundwater resources in the county's plains, as well as a reduction in water inflow to the Doroodzan Dam and other water resources of Marvdasht County.
Therefore, about 587 milli meters of the crop's water requirement had to be supplied through irrigation from other resources, but the decline in groundwater levels and the reduction in the outflows of the Doroodzan Dam for irrigating agricultural crops did not provide the possibility of desirable irrigation in this region, and the wheat crop yield per unit area has significantly decreased in the water year under study.
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