عنوان مقاله [English]
As opposed to the ordinary impervious weirs, physical and chemical materials can transit to downstream through gabion weirs. Therefore, gabion weirs are structures with minimized environmental negative impacts and are well known as environmental friendly structures. In this study, the effects of material size, upstream slope and downstream slope were investigated on the discharge reduction factor on gabion weirs under submerged flow conditions. At first, having identified the effective parameters the general dimensionless relationship was developed. For conductions of experiments, 16 models of gabion weirs constructed in a horizontal flume with 15m long, 0.3m wide and 0.5m deep. The tests were accomplished for different variables, including discharge, upstream and downstream depths, material size and upstream and downstream slopes. The results showed that the flow reduction factor decreased as the ratio of upstream to downstream (Y2/Y1) increased. For a constant ratio of (Y2/Y1), the flow reduction factor increased when upstream or downstream slope increased. It was found that the material size has no significant effect on the flow reduction factor. Base on regression analysis, an empirical equation was developed for estimation of the flow reduction factor which its correlation coefficient variation was from 0.12 to 0.91.