كليدواژه :
Afgeh , رسوب , Gozledareh , Alborz southern region , Sediment yield , MPSIAC model , Emameh , پسياك اصلاح شده , كشاورزي , Roodak , دامنه البرز جنوبي
چكيده لاتين :
Many of the small and mid-size watersheds in Alborz south ranges are un-gagged for estimation of the sediment yield, and therefore, having a suitable empirical model to estimate the sediment yield is essential for any soil conservation and watershed management in this part of the country. How ever these types of models should be calibrated through some gagged watersheds in the similar environmental setting to validate the empirical models to be able to use them in the un-gagged watersheds. In this study, MPSIAC (Modified Pacific South-West Inter-Agency Committee) model is used for estimation of six gagged sub-watersheds in the Alborz south ranges to validate the model.Six gagged small to mid- size watersheds of Ernameh, Roodak, Afgeh, Siara, Bilagan and Gozledareh with the range of 1800-6000 hectares are used for this validation study. The comparison of the observed sediment yield in the gagged station at 1 persent level in the Emameh, Roodak, Afgeh and Gozledareh watersheds with the estimation made by the model have no significance differences. How ever in the other two watersheds, Siara and Bilegan, the difference were significant at the same significant level, therefore, this model is not recommended to be used to estimate the sediment yield of the similar watersheds in this area.The poor estimation of the topography and land use factors and the low number of the sediment data collection years in these two watersheds were the main reason for the failure test.The difference between the observed sediment yield and the estimation by the model were 27.8, 43.2, 46.46, 80.9, 64.4 and 13.5 in Emameh, Roodak, Afgeh, Siara, Bilegan and Gozledareh, respectively.
