特高压输电线路在河流滩地立塔时，需要进行滩地塔位选择和方案比选。采用地表水模拟系统（surface water modeling system，SMS)，分析了河流滩地在设计洪水条件下的流场分布情况，并根据滩地流速分布对跨越塔位置进行选择和评估。SMS的计算结果直观、合理，可为线路选择滩地流速相对较低、局部冲刷深度较小及对河道行洪影响较小的位置立塔。

Multi-location comparison is needed when towers have to be installed in the river floodplains for UHV transmission lines. The surface water modeling system (SMS) is used to analyze the flow field distribution on the floodplain under design flood, based on which the towers location for large-span transmission lines are selected and assessed. The calculation results of SMS are direct, reasonable and can provide a good basis for choosing the tower locations in floodplain where the flow is small, the scouring depth is small and the tower has little impact on flood passage.