Abstract
In this study, a laboratory flume was used to calculate the water depths upstream and downstream of stepped gabionade-spillway with five different mono-sized gravel samples. A total of 175 experimental tests has been conducted with variation of discharge values within a range of 0.0007-0.0150 m3/s. Results indicated that the discharge has a positive effect and proportion on both upstream and downstream depths of water. Moreover, the detention depth value decreased with increasing the diameter of the gravel sample, while there is no effect of the gravel sample on the value of release depth. Obtained formulas for the detention and release depths can be usefully used for the design and scheduling actions in the field as it acknowledged a good matching between measured and calculated values. The errors percentage in average value for both detention and release tested values were 5.278% and -0.265% respectively.