TL;DR
swamp ground property so the the player is forced to reinforce ground before building / traversing the groundWhat ?
a swampy ground so the player needs to reinforce the ground with a cooling curtain to be frozen likewise sometime its used for ice-prone roads (the sayed roadpatches are heated, but the principle is similar) or so like the barrier by the fukushima-reactor.without that the player can only walk on it.
Building /rails / vehicles can only use this ground if its frozen.
Biters should traverse the swamp ground easy
Why ?
It would add varity / tactical to the map/generator.You will need a cooling curtain,which affect some 5 (numbers is extimated) tiles to make the ground frozen.
You will need beside the pipes a supply of coolant, which will need an additional line of production (water -> coolant -> inverse-heatexchanger -> pipes -> coolant-curtain
If failure in the supply then the ground should not be usabel, best would be a damage to all the placed on buildings / rails.....