This should help

Actually, designing a swale or even a rain garden is a good idea for many gardens, even quite small ones. And it really doesn't make too much difference with the dryness - or not - of the climate. Unless already existing as a low lying, water accumulating area (i.e. a bog or swamp, perhaps only seasonally), a swale will simply catch and retain rainfall and allow it to be gradually absorbed into the soil. Among the reasons for this is to avoid seasonal flooding of the landscape, to reabsorb pollutants that are present in storm run-off before they can reach streams and groundwater or simply to retain and re-use infrequent rainfall. In your case, the latter seems most appropriate although when it does rain in SoCal, that rain can come fast and furious, so the other two reasons may be equally as valid as well, at least on a now-and-again basis. A swale is just a low lying area......when rainfall does occur, the water will flow to the lowest point, the swale, so it does need to be constructed to be lower than current grade. If any slope to the yard at all, the swale should be located at the low point. If not, you need to grade your new "lasagna" planting to slope away from the structure and toward to the designated swale site. And you will need to excavate the swale to some degree, depending on the thickness you can manage with your lasagna method. I doubt constructing swales was devised with a lasagna method of bed construction in mind. It does involve some work to do it correctly. Grading and directing water runoff to the correct area is critical. And you want something that slows water penetration yet provides good drainage at the bottom of the swale, not just soil - coarse sand and river rocks or coarse drainage gravel are common. And yes, this is much more of a landscape design issue than just a soil question ;-) Do some research online to see how to construct an effective swale. Even check out rain garden sites - they are a wealth of information for this sort of activity if for a slightly different purpose. One other thing you may want to do is investigate dry stream beds as a landscape feature. Not only do these make an attractive focal point to a drought tolerant garden, they will help to direct any rainwater runoff (even irrigation run-off) to the appropriate swale location where it can be dissipated evenly through the soil profile. Where moisture accumulates surrounding the swale and along its sides is where you can locate more thirsty plants. If you don't already have a landscape designer, you might want to consider hiring one. They could be a huge help in the layout, design and construction of this kind of feature, as well as offering suitable planting suggestions.

Hello: I just discovered this web site and will be happy to join the battle of the swale! I live on a street that divides N. Miami from unincorporated Dade. I live in a townhome on the unincorporated side. There is a beautiful swale that stretches along in front of our townhomes filled with fully grown & neatly trimmed ficus trees. There are some low growing shrubs as well. There are 5 buildings that each hold 4 townhomes in our small development. Unfortunately, some of the residents are renters, not owners! Some of them have now decided to park in our beautiful swale on a daily basis. Of course, it obstructs the view of vehicles exiting our comples and will eventually destroy the grass. I have contacted our developer who runs the association and he said that unfortunately, there is nothing they can do to stop people from parking in the swale. It does not belong to us although we maintain the area. Eventually, it is going to destroy everything! The part that bugs me is across the street there parking available all along the street! They are just too lazy to walk an additional 10 feet! If you travel thru the areas of N. Miami where there was once some beautiful homes (some still are but few and far between), the swales have been destroyed and are now nothing but dirt ditches. People moved into these homes with many many family and friends (to lower the cost) and have parked cars across the property and swales. Many homes that once looked beautiful are now decrepid, overgrown dumps that look like car lots! What a shame the city has not done a thing to change the laws! I am afraid this is what is going to happen to our complex and area if nothing is done to change the laws regarding parking on the swales.

just really heavy rains, usually 2-3 times a year. This year we had more. I am not so worried about insects as rot and mildew from moisture, and keeping small animals out. The ground is sloped for good drainage and we are going to keep that slope. Water does not sit in that area. We will have weed fabric on the ground with gravel over it, whatever that is worth.