covered channel是什么意思

用法例句

in the urban drainage covered ditch system were discussed.

针对施工现场的技术难点给出相应解决方案,并对城市排水暗渠与大管径管线进行经济对比分析。

Brief summary about large scale abstraction conduit design

关于大型排水暗渠设计的小结

In Beishu Reservoir,the displacement destruction appears at the underground conveyance canal because of ageing without repair.

由于工程老化,年久失修,北墅水库输水暗渠墙体多处发生位移破坏,严重影响工程的正常使用。