INTRODUCTION: SHOALING DUE TO SEDIMENTATION IS ONE O THE MAJOR PROBLEMS IN NAVIGATION CHANNELS. TIDAL CURRENTS AND CURRENTS DUE TO BREAKING EFFECTS ARE MAIN REASONS OF SEDIMENTATION AND EROSION IN THESE CHANNELS. IF TIDAL CURRENTS FLOW ALONG THE CHANNELS, USUALLY WE EXPECT TO HAVE UNIFORM SEDIMENTATION OR EROSION BUT THE FACT IS SOMETHING ELSE, SO THAT IT IS IN THE FORM OF PAIRED HOLES AND HILLS, CALLED “RIPPLE”. IN THIS PAPER, WE STUDIED GENERATION AND DEVELOPMENT OF THESE RIPPLES IN BED OF SAJAFI PORT AT ZOHRE RIVER. FOR THIS PURPOSE, USED NUMERICAL MODELING ACCOMPANIED WITH THEORETICAL STUDIES. RESULTS PERFORMED THAT DISTANCE AND DIMENSIONS OF RIPPLES ARE RELATED TO WAVE LENGTH, CURRENT VELOCITY AND BED ROUGHNESS. IN THIS CASE, LOTS OF RESEARCHES HAVE DONE BY VARIOUS PEOPLE, RECENTLY. FOR INSTANCE WE CAN MENTION TO CHENG, H. Q., KOSTASCHUK, R. AND SHI, Z. (2004); LEO C. VAN RIJN. (2007); FAN DAIDU (2012); OURMIE’RES, Y., CHAPLIN, J. R. (2004); VILLARET, C., HUYBRECHTS, N. (2012).