optimum design of sedimentation basins in irrigation networks

abstract one of the problems in design of irrigation structures is sedimentation control in the inlet to the irrigation networks. water quality for agriculture requires that the sediments be controlled and reduced to the permissible limit at their entrance point to the turnouts and irrigation networks. this is possible by constructing a sedimentation basin. the bigger the basin, the best the retardation of the sediments, but the expenses are higher too. different mathematical models are developed for sedimentation basins. most of these models show the relationship between efficiency and effective parameters by mathematical formulas. in this research, a computer software for design of settling basins was designed in which design parameters (length, width, depth, slope and water velocity in the basin) are determined such that the basin has the specified technical characteristics and it is built with minimum cost. in this respect, operations research and a lexicographic enumeration algorithm is used. application of this software for evaluation of construction costs of sedimentation basins in nekouabad diversion dam zayandehrud irrigation networks at isfahan) showed that efficiency of these basins is 50.6% and 46.5%. if these basins were built under optimum design, about 18% and 6% would have been saved in their construction costs, respectively. .