Rainfall Temporal Pattern for Khorasan Province, Iran

Document Type : Original Article

Authors

1 Graduate student of Irrigation, College of Agriculture, Ferdowsi University of Mashhad, Iran

2 Research Assistant, Agricultural Research Center of Khorasan, Iran

3 Associate Professor of Irrigation, Ferdowsi University of Mashhad, Iran

Abstract

Rainfall time pattern has a marked influence on design of dams, urban runoff collection systems, culverts, drainage systems and or determining, flood potential and soil erosion. In this research, data of 18 rainfall autographic stations of Khorasan province of Iran were used to implement the rainfall time pattern. Rainfall depths were extracted for each time interval from rainfall charts and were categorized to four quarters. A ranking method was used to arrive at rainfall time patterns corresponding to time intervals of 1, 3, 6, 9, 12, 18, and 24 hours. After normalizing the rainfall mass curves, every quarter of rainfall was ranked, where rank 1 was given to the highest. The final pattern was derived by averaging the quarter ranks and percentage of rainfalls corresponding to each duration. A contingency table was used to verify the independency of rainfall time patterns by a chi-square test. The results showed that in Khorasan province: a) most of short duration rainfalls are first quartile, b) most long-term rainfalls are second quartile, and c) on overall more than 50% of rainfall amounts for nearly all rainfalls in this arid and semi-arid region occurred in the first half of their period.  

Keywords


امین، سیف ا… ، سپاسخواه، علیرضا و کشمیری پور، بهداد (1379) ، ”بررسی الگوی توزیع شدت بارش در پایه‌های زمانی مختلف در استان فارس”، مجموعه مقالات دومین همایش ملی فرسایش و رسوب، دانشگاه لرستان، صفحات 241-255
 بزرگ زاده، مصطفی (1374) ، ”توزیع زمانی بارش برای محاسبه سیلاب طراحی” ، فصلنامه آب و توسعه، سال سوم، شماره 1، صفحات 35ـ49.
 رضیئی، طیب و علیجانی، بهلول (1381) ، ”تعیین الگوی توزیع زمانی بارش‌های کوتاه مدت در استان تهران”، مجله نیوار، سازمان هواشناسی.
 طالب بیدختی، مجید (1374) ، ”الگوی توزیع زمانی بارش استان سمنان”، پایان نامه کارشناسی ارشد، دانشکده کشاورزی، دانشگاه تربیت مدرس.
وزیری، فریبرز (1376) ، ”تعیین الگوی توزیع زمانی بارندگی‌های 24 و 48 ساعته در جنوب غرب ایران”، دانشگاه صنعتی خواجه نصیرالدین طوسی.
Chuckwuma, G. O. and Schwab, G.O. (1983) “Procedure for developing design hyetographs for small watersheds”, Transactions of the ASAE, 26(5), pp. 1386-1389.
Hershfield, D.M. (1962) “Extreme rainfall relationship”, Journal of Hydraulics Division, ASCE, 88(HY6), pp. 73-92.
Huff, F.A. (1967) “Time distribution of rainfall in heavy storms,” Water Resources Research, 3(4), pp. 1007-1019.
Keifer, C.J. and Chu, H.H. (1957) “Synthetic storm pattern for drainage design”, Journal of Hydraulics Division, ASCE, 83(HY4), pp. 1-25.
 
Kent, K.M. (1968) “A method for estimating volume and rate of runoff in small watersheds”, TP-149, SCS, U.S. Department of Agriculture.
Pilgrim, D.H. and Cordery, I. (1975) “Rainfall temporal patterns for design flood”, Journal of Hydraulics Division, ASCE, 101(HY1), pp. 81-95.
SCS. (1986) “Urban hydrology for small watersheds”, Tech. Bul. 55, Appendix B, pp. B-1 and B-2.
Telvari, A. R. and Ghanbarpour, M.R. (2002) “Rainfall temporal pattern in synoptic meteorological stations in North of Iran,” Proceedings of the Third International Conference on Water Resources and Environment Research, Derseden University of Technology, pp. 275-279.
Yen, B.C. and Chow, V.T. (1980) “Design hyetographs for small drainage structures”, Journal of Hydraulics Division, ASCE, 106(HY6), pp. 1055-1076.