Groundwater sinks footings and can cause hardwood floors to buckle
Groundwater in your crawlspace and sinking spot foundation footings in your crawlspace can cause your lovely hardwood floors to buckle and crack. There are other aspects concerning the condition and dryness of the wood that is used in the floor that can contribute as well, but it is not uncommon for wetness and standing water in the crawlspace to cause major damage to hardwood floors.
Hand excavated french drain groundwater removal systems are a line of defense that you must have if your hardwoods are important as an investment to you.