comparison investigation of different techniques for design of irrigation settling basin structures

abstract settling basins are essential hydraulic structures which have to be designed and constructed at all river water intakes to remove most of suspended sediments which enters the intake by flowing water. there have been many techniques for designing these structures. to simplifying the design procedure, some of these techniques have been applied many assumption and some others are so complicated which are difficult to apply or needs many data for design purpose. there are also some applicable methods which have been developed based on experimental or analytical procedures, but their results are not well known. thus it is the purpose of this paper to compare these available methods. to do so extensive experimental tests were conducted in a flume of m using three different sediment concentrations under three froude numbers. field tests also were conducted in an irrigation rectangular concrete canal of 200 meter long, 1 meter wide and depth. field tests also have been conducted under there different discharges different sediment concentration. then the experimental data was used to determine the trap efficiency of settling basins by different methods. the predicted values were compared to the measurement values. the result indicate that the method of swamee and tyagi over predict the trap efficiency. this method was found to be more sensitive to the input data. result obtained by the methods of jin and kaveshnikov were found to be more close to measure data than raju and garde methods. in this study a coefficient of jin method in irrigation settling basin was determined for best estimating of.