Design of Minimum Cost Earthen Channels Having Side Slopes Riveted With Different Types of Riprap Stones and Unlined Bed by Using Particle Swarm Optimization

Abstract

AbstractSeveral design alternatives for a trapezoidal earthen channel whose side slopes are riveted with riprap stones and bottom is unlined were analysed to compare the performance of different types of stones (round, sub‐round and sub‐angular, and angular) for minimum cost and performance effectiveness. Particle swarm optimization (PSO) algorithm was implemented to determine the minimum cost channel in contrast with earlier alternatives relating to the most hydraulically efficient sections. Both clear water and sediment‐laden flow conditions were applied to investigate the effect of flowing water characteristics on optimality, which is not available in the literature. Optimal design of channels incorporating land acquisition cost is scanty; therefore, land cost was also included in the objective function. In addition to the design of a channel without freeboard, different freeboard scenarios, including depth‐dependent equations, were applied to assess the impact of freeboard provision methodologies on optimal channel dimensions and cost. It was found that the channels having angular riprap revetment for sediment‐laden flow conditions offered the minimum cost of construction, with sub‐round and sub‐angular, and round stones coming next in sequence, and the freeboard provisions also impacted the channel shape, dimensions and cost. Copyright © 2016 John Wiley & Sons, Ltd.