Journal of Applied Sciences

Year: 2006 | Volume: 6 | Issue: 12 | Page No.: 2565-2571
DOI: 10.3923/jas.2006.2565.2571

Spatio-Temporal Assessment of Historical Droughts using SPI with GIS in GAP Region, Turkey

Tahsin Tonkaz

Abstract: A study was carried out to investigate drought behaviors of the Southeastern parts of Turkey using SPI method for the period from 1962-2002. The multiple-time scaled SPI results were only evaluated for the rainy season of the area, from October to May. Point-wise indices were interpolated over the whole area using inverse distance technique in order to obtain areal extending of the drought quantity. The results indicated that a dramatic and widespread drought event was recorded in the year of 1973 at most of the stations and drought categories. However, regardless of drought severity, an extraordinary dryness was experienced from October 1999 to May 2000; the whole study area was under drought conditions for all months. In February of 1989, extreme drought was dominant over the region in the 2 month drought category. The highest SPI value of -5.46 was observed in May of 1984 at the Siverek station. A prolonged drought was experienced in the 12 month category that was successive for 49 months; from March, 1970 to March, 1976 in Siirt. The overall outcome of this study exhibits that hazardous droughts were experienced from time to time across the study area during the examination period. Those dry terms come out with unfavorable results on agricultural practices and water resources in the area. The lowest cereal yield and operational water levels of major dams were recorded during those unusual dry years. Better management of natural resources will be a good solution to overcoming these kinds of natural problems in the similar regions.

Keywords: SPI, drought, GIS and areal extending

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