The problem of water scarcity can be noticed clearly in the lined canals which provide the irrigation networks. Using porous structures like gabion weirs contributes as a part solution to this problem. In the current study, a laboratory flume was used to calculate the water depths upstream and downstream of the stepped gabion weir that is to be put inside it at a certain distance, and this flume comes with dimensions of 10 m long by 0.30 m wide and 0.50 m height. While the tested hydraulic model of the weir was built with dimensions of 0.30 m width by 0.40 m maximum height, and five lengths with different total distance of 0.88, 0.96, 1.08, 1.12, and 1.20 m respectively. The used gravel samples to fill the gabions were of monosize query gravel with diameters ranging between 0.0095-0.0140, 0.0140-0.0190, 0.0190-0.0250, 0.0250-0.0375, and 0.0375-0.0500 m in a respective way. While the values of discharge, measured during the experiments were in the range of 0.0007-0.0150 m3/s, and a total of 175 trial tests. This study achieved that the detention depth value decreases by increasing the diameter of the gravel sample used, but there is no effect of the gravel sample on the value of release depth, the different illustrated formulas for the detention and release depths maybe can be used usefully for design and scheduling actions in the field where it gave a reasonable matching between the measured and the calculated values of the studied depths, and finally, the errors percentage in an average value for both detention and release tested values were 5.278% and -0.265% respectively