I've seen drills put through the wringer and live to tell about it. Unless you stick it in a pool of water, you drill should survive some hole digging. Don't know of dirt augers for a drill, but nothing would suprise me. Think of the lil' ol' paint mixer drill attachment. The auger would probably be about the same. Some type of screw design.
When you are done, just clean off the drill before you put it away!
