Boardwalk

A boardwalk (alternatively board walk, boarded path, or promenade) is an elevated footpath, walkway, or causeway typically built with wooden planks, which functions as a type of low water bridge or small viaduct that enables pedestrians to better cross wet, muddy or marshy lands.

The boards helped to keep the soldiers' feet dry and prevent the development of trench foot, caused by prolonged standing in waterlogged conditions.

[9] Combat troops on nearly all sides routinely wore hobnail-style trench boots that often slipped on the new duck boards when they were wet, and required extra caution.

Unfortunate soldiers were left struggling to rise under the weight of their equipment in the intractable and sometimes deep water or mud.

If this happened at ground level during a tactical advance, the rising soldier could be left a defenseless target for enemy fire as well as hinder forward progress.