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Beaver,
Do you know how much water you will need to handle? Is there a big paver area that will drain toward the wall, or is this pretty minimum?
Stonehenge thought your soil looks pretty sandy. It looks pretty tight to me. If it does drain well, then you have the right idea to some degree. I live in a sandy place and drywells such as what you describe are very common place and often required at downspouts from roof gutters. Typically, they are larger than a 5 gallon bucket. Usually 2' in diameter and 2' deep. Some people used corrugated plastic drain pipes cut short and stood on end with lots of 1"-2" holes drilled in. Others buy precast concrete ones, or a snap together plastic kit from a home center (I think "Aquaflo" is a brand name.
Anyway, you do not put stone inside it. You put stone around it and a lid on top of it and filter cloth over the entire thing to keep the soil from settling into it.
The idea is that the "tank" holds a bunch of water and it flows out into the big voids within the stone. The wider the stone area, the more water can be held because there is a greater amount of void space if there is more stone. That holds the initial volume of water that comes into the drywell, but there is more to the story. It is the absorption of the water into the soil that counts. The greater the surface of soil that you can expose that water to, the more efficient the absorption. There is the bottom area of the hole and sidewall area that is going to accept that water. If you know the percolation rate in your soil and how much water will be entering the drywell, you (or at least someone who knows how to do it) could calculate how big to dig the hole and how much stone needs to be around the drywell. We do it all of the time.
If your soil does not perc fast, it will not be very effective. Daylighting the pipe would be the way to go.
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