It all began with my In Law's yard.
When I saw how much they had completed back in October, I came home and immediately went to work digging a hole for a (at the time) non-existent tree. When I felt the hole was sufficient, I moved onto digging a hole at the end of our dry river bed. Over time, the end (just out side of the rocks) started eroding away (technically its probably more like when the water ran out of the bed it wasn't spread out enough). In my gardening-high, I decided that the universe was telling me I needed a rain garden. Thus the hole. A spur of the moment decision with little to no planning. Of course the husband was a bit more concerned about this hole in the middle of the yard and my telling him "don't worry! it'll be fine, you'll see!" didn't really placate him. So just to show him it would be fine, I didn't do ANYTHING on the project for the next 3 months.
Before-ish. below shows the area already dug out and full of rain water (it's about 6" deep at the center). I didn't do the saturation test like I was supposed to (mostly because I know the rainwater doesn't stay around for long in the actual dry river bed plus I figured that a hole not lined with landscape fabric would drain even quicker), but Mother Nature helped out and did the test for me - good news, it drains within 24 hours:
After: the plants are planted, mulch placed and rocks on top of that (Yes I realize this isn't a very good angle since you can't see how it is tied in with the original rock bed). I didn't have to buy any additional rock - the rock around the outside all came from the front yard Hell Strip area - the previous owners had rocks interspersed with the jasmine. The jasmine just grew over them over time, and so when we removed the dead jasmine (yes, we were lucky and the combination of full sun and no water finally killed off the hell strip jasmine), we found a plethora of rock. The rock that filled in the hole came from the dry river bed - in some places the rocks are 2-3 deep, so I just looked for loose rocks that didn't expose any of the landscape fabric and moved them over to this area:
Close up showing the plants - top left: Artemisia; top right: Gregg's Mistflower; bottom: Peter's Purple Monarda (picture taken immediately after planting). I realize that none of these may be considered rain garden plants and they may all die. That is fine. I didn't have to pay anything for these plants as they're all from plants I already have in the front yard. The artemisia is planted at the high point so I don't actually expect it to ever be under water (see first picture - the artemisia is at the high point between the original river bed and the new part). If it does grow, it should hopefully spread along the ridge and will act as a spreader and slow down the water coming into the garden. The Gregg's mistflower at the other end should hopefully grow and also act as a spreader and slow down the water leaving the garden (thus preventing any more eroding of the lawn area).