ASSESSMENT OF SOIL EROSION, SEDIMENT YIELD AND MAXIMUM OUTFLOW, USING IntErO MODEL (CASE STUDY: S8-intA SHIRINDARREH WATERSHED, IRAN)

The complexity of hydrological processes, spatial and temporal variation of all effective factors and lack of essential measured filed data convinced researchers to use empirical models in various scales. The IntErO model was used to predict maximum outflow (Qmax), soil erosion intensity (W year) and sediment yield (G year) in one of the internal sub-watersheds of Shirindarreh watershed, northeast of Iran. The results showed that the peak flow was 13.51 m3s^-1 for a return period of 100 years. As an internal area, the peak flow of all upstream sub-watersheds should be also considered to be added to the predicted peak flow. The value of Z coefficient of 0.696 indicated that the river basin belongs to III destruction category and the strength of the erosion process was medium, and according to the erosion type, it was intrusive erosion. The predicted gross soil erosion in the study sub-watershed was 8.06 ton ha^-1 year^-1. The coefficient of the deposit retention (Ru) or sediment delivery ratio (SDR) was 0.124 and therefore, the sediment yield was 1.00 ton ha^-1 year^-1. According to Gavrilovic, the study sub-watershed is a region of very weak erosion.