Slowing down the water made the plants thrive

I realize it might not look like much in the picture but in person it actually looks pretty. We had an area where the water drained from essentially the whole street and went straight down into a creek. As you can see it was all rocks on top of clay soil.

I started digging some holes along the path to maybe slow some negligible amount of water down and even though it’s small, the plants started thriving in those areas. I don’t think this can be considered a real rain garden, but the more I slow it down along the path the more natives thrive. I added some more plants, river sea oats, soft rush, big blue stem (further away) and I hope that the sedges spread on its own as well.

The soil is heavy clay that turned into hard rock surface but now I’m able to actually plant stuff around this area with more ease.

Any advice for what else I can do/how to improve the area?