Collector Traditional Cache

The cache is a small, magnetic Altoids tin.  Access to this area is via forest road 4N21 which is open to hiking, biking or horses.  Occasionally, the road may be open to vehicles but it's pretty rare and you'll probably need to park at the given parking area.  Follow the forest road until coming to the trailhead (coordinates below) then take the single track trail toward the cache.

The trail to the cache is very beautiful as you walk, bike or ride in the shade of hundreds of pine trees.  It's all very natural until you come across the "collector", a small structure setup to collect rain water.  I'm not really sure what its purpose is, I initially thought that there might be an underground pipe running to somewhere below, but to try to run a pipe down amongst all the trees and vegetation would be a huge project.  It might be some sort of animal watering trough, but the tank below the structure is not very accessible to anything but the smallest animals.  Any ideas?