This works covers the requirements and conditions for the design and construction of surface drains, drain channel, subsoil drains, perimeter drain, pipe culverts, box culverts, sumps, sluice gate, other drainage structures, excavation and backfilling for drainage works.这项工作包括了设计和搭建开挖和回填排水工程的明沟，下水道，地下水道，周边水道，管道涵洞，箱型涵洞，污水坑，水闸以及...
This works covers the requirements and conditions for the design and construction of surface drains, drain channel, subsoil drains, perimeter drain, pipe culverts, box culverts, su...
