Saeed Reza Sabbagh Yazdie - Civil Engineering Department, KN Toosi University of Technology,
Mohammad Reza Namaee
Mohammad Sadegh Jalaledini - The Research Institute for Water Scarcity and drought,Tehran,Iran
Mahdi Habibi

Side weirs are widely used to divert flows from rivers, canals, sewers. However, the hydraulic behavior of this type of weir is complex and difficult to predict accurately. Most previous researchworks for the side weir were carried out in canals with rectangular cross sections and zero weir height. Also in smooth channels with no significant roughness coefficients However, in floodwater spreading systems and most common irrigation systems, canals have trapezoidal cross sections, weir heightgreater than zero and with nearly rough bed. In this study, the discharge coefficients and overflow discharge over the side weirs was experimentally investigated in a rough-bed flume with manning coefficient of nearly 0.02 under sub-critical condition. Over 20 experimental tests were carried out.The experimental data were compared with other researcher’s formulas and finally a new formula is proposed for prediction of discharge coefficient for side weirs in floodwater spreading systems

Discharge Coefficient, Side Weir, Floodwater, Spreading Systems,