Rain gauge cache
A Rain Gauge Cache is a floating container placed within a vertical tube. The cache is retrieved by filling the tube with water, so the container floats to the top.
A typical rain gauge cache is a micro-cache placed within a vertical PVC pipe that is secured to a tree or post. Water can drain out the bottom of the pipe through a screen, or through drain holes in a PVC cap. The screen or cap prevents the container from falling out the bottom of the pipe. To retrieve the container, one must plug the drain at the bottom and then fill the pipe with water. The cache will float to the top of the pipe. Once the bottom of the pipe is unplugged, the water drains out and one can drop the cache back into the pipe.
The container for a rain gauge cache must float and should be waterproof. The log sheet should also be waterproof.