Right now, the water district in my area is draining one of the biggest resivoirs around here (and one of my favorite bass spots).  I know that they won't drain out completely, but there are some places that have already gone down to about a foot (or in some places less).  I know the water will become unsuitable if there is not enough oxygen (if that plants start dying out).  How shallow can it get before my spot is completely screwed?

When the water drops or when the oxygen levels fall bass will drop back to deeper areas. Your larger bass would be the first to leave because they require more oxygen and food that smaller fish. When the area fills back up the larger fish will move back as they follow the influx of bait in the shallows. You should find them on points or right next to a drop or bluff banks. That way they can have just a short distance to deep water.