The side-weir by definition is a fixed structure, which is installed at one side or two sides of the main channel. When water surface elevation is raised to a specific level (crest of side weir), water overflows over the side-weir and flows into the side canal.. A complet analytical solutio of the equatio governing the flow i side weir channel i not possible and until quite recently approximate method have bee used ,based o experiment conducted over a limited range of the many variable involved. I many cases , the use of such approximate method ha involved substantial error i the calculated spill discharge. In this study a comprehensive set of tests has been conducted o plane and labyrinth side weirs. Also, due to the use of groups of piles and guide vanes, the hydraulic conditions of side weir inflow were changed and resulted to better efficiency of these structures. As the primery work i this research the flow hydraulic charasteristic for plane and labyrinth weir have bee studied for both cases of presence and absence of guide vane and groups of piles. Finally the effects of guide vanes and groups of piles on flow discharge coefficent and water free surface profiles are investigated. Result show that due to the use of guide vanes and groups of piles the discharge coefficeint of plane and labyrinth side weirs increses up to 30 percent and due to the use of these devices the flow discharge of side weirs increses up to 45 percent.
