The way I am doing this bed, I hope will help with both too much water and not enough. It is called the Hugelkultur way to garden. Where you dig down a bit and add wood. The wood will act like a sponge. and wick it into the roots of the plant. And by it being raised. The water will not stay in the bed to flood the plants. When we have excessive rain. So I hope this combo. Will make the water level just right.