Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran

Annals of Warsaw University of Life Sciences – SGGW
Land Reclamation No 42 (1), 2010: 51–60
(Ann. Warsaw Univ. of Life Sci. – SGGW, Land Reclam. 42 (1), 2010)

Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran

A.V. KHALEDI DARVISHAN, S.H.R. SADEGHI, L. GHOLAMI
Department of Watershed Management Engineering, College of Natural Resources and Marine Sciences, Tarbiat Modares University, Iran

Abstract: The proper prediction of temporal and spatial variation of sediment yield from the watershed is a need for sediment control, river engineering and soil and water conservation studies. The present study was therefore planned to simulate the sediment graphs for Chehelgazi watershed in Gheshlagh dam upstream in Kurdistan Province, Iran, by using Time-Area Method. Towards this attempt, the study watershed was divided into 7 time-area segments based on the time of concentration. The soil erosion in each segment was estimated using the USLE and then routed to the main outlet using sediment delivery ratio as a function of land slope in two adjacent time-areas. The temporal variation of sediment was ultimately predicted with the help of lag time of sediment arrival to the outlet and the concept of superposition for 11 storm events, which occurred during winter 2006 and spring 2007. The comparison between estimated sediment graphs with corresponding observed ones verifi ed the weak capability of the model in simulation of sediment graphs under consideration. The results also verified the calibration necessity of the model to achieve appropriate estimation for important components of the sediment graphs. The results of the calibration finally proved the considerable capability of the model in predicting of total volume of sediment yield with respective estimation and verification errors of 30.93 and 33.40%.

Key words: Chehelgazi River, Iran, sediment delivery ratio, temporal variability of sediment, Time-Area Method (TAM)

Streszczenie: Efektywność metody TAM (Time-Area Method) w symulacji zmienności czasowej wydatku rumowiska ze zlewni Chehelgazi, Iran. W artykule przedstawiono zastosowanie metody TAM do symulacji zmienności czasowej wydatku rumowiska ze zlewni Chehelgazi, położonej w prowincji Kurdystan w Iranie. Zlewnię Chehelgazi podzielono na 7 zlewni cząstkowych, biorąc za podstawę czas koncentracji odpływu rumowiska. Do wyznaczenia masy rumowiska transportowanego w czasie wezbrania opadowego wykorzystano uniwersalne równanie strat glebowych USLE. Na podstawie sedymentogramów 11 zarejestrowanych wezbrań opadowych przeprowadzono weryfikację i kalibrację metody TAM. Błąd estymacji i weryfikacji całkowitej objętości wydatku rumowiska ze zlewni wyniósł odpowiednio 30.9 i 33.4%.

Please use the following format to cite the selected article:
KHALEDI DARVISHAN A.V., SADEGHI S.H.R., GHOLAMI L. Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran. Annals of Warsaw University of Life Sciences – SGGW. Land Reclamation No 42 (1), 2010: 51–60

Authors’ addresses:
Department of Watershed Management Engineering
College of Natural Resources and Marine Sciences
Tarbiat Modares University
Noor 46417-76489, Mazandaran, Iran
e-mail: vahedkhaledi@yahoo.com

KHALEDI DARVISHAN A.V., SADEGHI S.H.R., GHOLAMI L. Efficacy of Time-Area Method in simulating temporal variation of sediment yield in Chehelgazi watershed, Iran

DOI 10.2478/v10060-008-0064-8