It wasn't entirely intentional -- truth be told -- but when I dug out the path to make the raised spiral row by flipping the path vegetation (used to be my "sunny meadow" so all kinds of non specific tuff, not just grass) onto the row, I went almost down to the clay subsoil in my enthusiasm, and ended up with greater path-to-row difference than I originally planned. But I did also recognize the Emilia Hazelip-esque design factor.
The ground is graded in a slope away from the house and the house corner downspout to the right of the blue spruce where the rain barrel overflow used to just drain right past this area to the upper left corner where the fence meets in a corner and I have the former Carolina Gold rice paddy, now designated Native Bog Garden.
The water drains out from the outlet there to a shallow swale that wraps around my Front Yard Fence Row, and then on down the front lawn to the side walk. Thanks to the new Spiral Garden catchment, there are less water that makes it all the way to the sidewalk to puddle uselessly. Just need a few more plantings in the front yard to capture them all and not let them go on down to the street.
Now the spirals catch and sequester the water and appears to fill the lower/far half of the outer and inner spiral including the center which had a fairly deep topsoil (I think it's because there used to be a path through here that I always mulched heavily) that got piled up in the middle.
As for the goldfish and the minnows -- yep, they usualy run around 12¢ each now, though I got these for 10¢. I tell the kids not to get attached... That these are "sacrificial" (though we'll do our best to catch and rescue them when the water level goes down since they help us with the mosquito larvae) So they choose the plainest, most average fish out of the bunch. They hold back the black tail tip and white/red bicolor ones to keep in a 5 gal bucket as well as the main holding tub with air pump -- which of the fish are happier, I wonder?