Document Type : Research Paper

Authors

1 M.Sc. Student, Department. of Watershed Management, Faculty of Natural Resources, Tarbiat Modares University, Iran

2 Assistant Professor, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Iran

3 Professor, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University, Iran

Abstract

Todays, dynamic models are supposed as the most important tools in erosion and sediment phenomena
due to their complexities and existence of many affecting factors. Towards, the present study was
conducted in the Kojour watershed for daily sediment modeling using daily rainfall, discharge and
sediment during 2007 to 2010. The modeling process was carried out all data and the monthly and
seasonally classification data in linear and nonlinear models. The results indicated that daily linear and
non-linear models did not indicate a suitable model. The monthly and seasonally classification of the
data led to achievement of better models with determination coefficient significant at 5 percent level
and relative error less than 40 percent as compared with those obtained from no classification. It was
also found out that daily sediment of Kojour watershed was affected by discharge occurred event day
and before four days. The discharge occurred event day is the most effective factor in 80% selected
models in the study watershed. The nonlinear models were better estimation than linear models in
July, September, December and March and autumn but linear models were better than nonlinear
models in other months and seasons.

Keywords