Constructing a Permanent Underground Cache, by JIR
…a couple of feet down. If not, you may still be ok if you use enough plastic to divert surface water around your cache. You can test your site by loading a cache drum or (perforated) bucket with a little cotton cloth (I used a couple of white bath towels), bury it using the same techniques you will use for your cache and leave it a year or at least leave it through your local wet season. When you dig it up and inspect, there should be no water damage to the towels and no evidence of water on the inside of the drum. One of my pails (buried in a flat, sort of wet forest floor) flooded in spite of the plastic sheeting, but the one buried into a slope had no sign of moisture at all. The ground water had passed over the top of the sheet and…