I'm thinking it wasn't a good idea to use the pics of last year's flooding, because that was very much NOT a typical event. It's also clear that in the interest of trying to not bog down my question with too much information, I left open too much for interpretation. There is a storm drain located just around the lower left corner of the flood picture. Clearly it's not working well, and I'm addressing that with public works. The storm drain directly across the street works great. Much of the water on my property actually comes from the far side of my property, not shown in this picture -- if you went through the gate that's behind my granddaughter in that flood picture and walked straight over to the other side of the fence, the lot on that direction is very large, and there is just enough slope from back in there yard to way over by the side street shown in the pic that when we have a hard rain you can go in the yard and watch the water rushing over my yard. So it's actually exactly oppposite from what it looks like -- water doesn't come in from the street, it comes from the opposite side and stops at the street. Another of the problems we're addressing is grading the back yard to try and get THAT neighbor's runoff to stay in their yard. What happens during a "normal" very heavy rain (as opposed to the 12" we got the day of last year's flood) is that the water comes from all directions and tends to pool right where you see my granddaughter standing, which is at the top end of an old swale which goes to the storm drain - that's why it seems so deep there: she's standing in the deepest part of the swale. But that swale has gotten built up with dirt over the years as you get closer to the drain, and so the water backs up there at the gate. Getting that swale dug back out is yet another of the things we're addressing. Here are some pictures that show the area dry: The right side of our driveway, showing the difference in height between my neighbor's property and my driveway. The same side of the driveway, taken from next to the shed. This is the left side of the garage, where water pools the most during a hard rain. If you look through the gate to the fence in the background, the lot behind that fence is where much of the water flows from. FYI, the gutter was installed today - it used to have the downspout back by the gate, right where the problems were the worst, so we put in a new one that discharges on the opposite side, and someone is coming out this week to route it to a drywell. So, to summarize: We have water coming from the far side of our yard, flowing across our yard. We're grading there to cut that down. We have an insufficiently functioning storm drain. We're working with Public Works. We have an old swale that no longer is sloped the way it should, so water stops there by the side of the garage. We're digging that out and reshaping it to let water flow the way it's supposed to. AND we have a neighbor to the side of our driveway whose lot is significantly higher than ours, and whose downspouts are tied into pipes that discharge right at our property line so that most of his roof runoff comes onto my property. There is no code preventing him from doing that and I'm not willing to drag him into civil court, so I'm trying to deal with it on my side of the property. THAT aspect of our stormwater problems is what my original email was all about. Sorry for confusing things so thoroughly by not explaining all the sources for the flood waters I showed, and for not making it very clear that this picture is NOT our typical problem; I had mistakenly thought it would be a good picture just to illustrate the difference in height of my property vs. this rear neighbor's lot, now I realize it confused things considerably. Maybe I should just ditch this thread and start all over...

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.

If I recall, you asked about plants for other areas of you sister's yard a year or two ago. If you have started her plantings, would you be willing to post some photos? Adding organic matter to the bed will help even out moisture as will mulch to make this a more successful garden. Here are some plants (some of which are natives so should be relatively easy) that are happy in a damp area. Many of these Dee mentioned, but here are comments based on my experience growing them. Shrubs: - Rhododendron viscosum (swamp azalea) has white to pink early summer flowers (just fading now) which are vanilla scented. This will only flower if it gets at least some sun. It gets some fall color also. Native - Clethra alnifolia (Sweet pepperbush or summersweet) has spikes of white to pink late summer flowers and clear yellow fall color. Some of the selections of the species are better than others for impact: Ruby Spice has pink flowers or Anne Bidwell sports clusters of white spikes or Sixteen Candles is compact with large white spikes. Flowers better in more sun, but tolerant of sun, shade, wet or dry. Some varieties will sucker. Native - Ilex verticillata (winterberry deciduous holly) has showstopping fall to early winter scarlet berries on bare branches, but needs at least half day sun to flower and berry well. Winter Red holds the berries the longest, according to research I've read and is the variety I grow, though only now getting large enough to berry. They may sucker some. Be sure to plant the appropriate male in an unobtrusive place in order to get berries. Native - High bush blueberries like some extra moisture, but not standing water, so could be planted in the less wet areas. Spring flowers, berries, fall color. Native - I think any of the shrubby dogwoods are pretty tolerant of wet feet and you can find them with various shades of red or gold twigs for winter interest as well as with variegated foliage. some native, some not, but all easy. Some will sucker. - There are various dwarf (4-12 feet rather than 30 feet) forms of Thuja occidentalis, eastern white cedar AKA arborvitae which grows in swamps if you want some evergreen interest. Deer like this if you have many of them . I haven't had any issues with them being eaten by deer. Native - Andromeda polifolia (bog rosemary) is a lovely low-growing evergreen, but can be fussy if it doesn't get even moisture and organic, acid soil. It is fine with part sun and has pink bells in spring and narrow, bluish foliage. Native - Ledum groenlandicum AKA Rhododendron groenlandicum (Laborador tea) is a low-growing plant with leathery leaves and clusters of small white flowers in spring. Native - Rosa palustris is a native wetland rose with single pink flowers in early summer and nice scent. The hips are decorative also. Native Perennials: - Caltha palustris (marsh marigold) has bright yellow spring flowers in wet areas, and the foliage will die back in summer if it's dry. It seems to do well in some shade since it grows and blooms largely before the trees leaf out. Native - Osmunda cinnamonea & O. clatoniana (cinnamon & interrupted ferns) both provide statuesque foliage for shade to part sun. They tolerate wet soil, but are happy if the soil is normal moisture also as long as it doesn't get both sunny and very dry. Native - Osmunda regalis (royal fern) is a tall lacy wetland fern with beautiful clear yellow fall foliage and requires wet soil all the time. Native - Veratrum viride (false hellebore) has large, pleated foliage that would make a good hosta substitute and needs to be in a wet area. Everywhere I know that this grows is in the shade. I've never seen it at a regular nursery, but you might find it at a wetland mitigation nursery or specialist nursery for wetland plants. Native - Camassia is a PNW native that likes moisture and has blue spring flowers. It can be purchased through good bulb suppliers like Brent and Becky's Bulbs www.brentandbeckysbulbs.com/ For late summer bloom, there are several large statuesque plants, including Eupatoriums and Veronias, but all need at least half day sun and are happiest in full sun. all native Eupatorium purpureum (now renamed by botanists as Eupatoriadelphus maculatus, common name joe pye weed) has clusters of mauvy purple fringy flowers in late summer. Eupatorium perfoliatum (boneset) has similar clusters of white flowers in August. Veronia has deeper purple flowers. Vernonia fasciculata (prairie ironweed) is tolerant of moist and dry conditions as is V. noveboracensis (New York ironweed.) - Iris versicolor (blueflag iris) is a native iris that I've seen blooming in full shade. It will bloom better in some sun. (As a side note, don't plant Iris pseudacorus, yellow flag, as it is an non-native that is invasive in wetlands.) Japanese and Siberian irises are happy with wet soil and will be fully hardy for you since I can grow them about an hour north of you. I'm not sure if Louisiana iris is hardy enough since I've seen various assessments of hardiness, but not grown them. - Lobelia cardinalis (cardinal flower) is a native that grows along streams and river banks, but will also grow in ordinary garden soil. I'd avoid Lobelia syphilitica (great blue lobelia) because IME it is a rampant self-seeder unless one always deadheads; ten or so years ago I removed them from by garden, but I am still finding volunteers in the garden, the lawn, the gravel drive, etc. - Clematis viriginiana grows along the steam on the floodplain in wet soil here, so should be fine for you. It will bloom less in less than full sun, but as long as it has more than 5 hours of sun should be fine. It has lots of tiny white flowers in late summer, sort of like sweet autumn clematis. - Clematis crispa is also native to swampy areas and has smaller bell-shaped flowers in shades of white and light lavender and mauve. - Clematis glaucophylla has pink and cream bells and also is native to lowlands along streams. Here is a site that will give you information about some of these native (though not all to NH) clematis: http://www.clematisviorna.info/ and here is a place that often carries some of these clematis http://www.gardenvines.com/. (You can request to be informed via email when they are back in stock since they are all currently out.) I tend to grow these small-flowered clematis near large shrubs so they can climb and ramble around whatever is nearby. They seem to play well with others as long as I let the shrubs get well-established first, so I tend to plant my clematis after the shrubs are 2 or 3 years old. They will also grow on a traditional obelisk or trellis. All want to get cut to about a foot sometime during the non-growing season, though they will do fine if not cut back, just will bloom higher on the plant. My favorite ground cover for average to wet garden soil and full shade to full sun is common cranberry, Vaccinium macrocarpon. It is another native, with tiny evergreen leaves, equally tiny pink flowers, and startlingly large red berries which persist until spring. It weaves well among other plants and never get taller than about 4 inches, though it may spread 2 or 3 feet in all directions, rooting as it spreads. It doesn't smother other plants, so it's a great groundcover to plant, though it will need mulch to prevent weeds coming up through it. It is denser in more sun.

g'day catherine, eric has got it one, but swales can be constructed (if that's the right word) in many ways ie.,. you could run rows of hay bails end to end if the slope is steep drive a garden stake through the middle of each as it takes time for this type of swale to settle in; or use a single tine ripper behind a tractor and rip along the contours (my favourite way less cost & physical input & they can be used as temporary so you can put a new swale elsewhere plus if you are planting trees planting them along the rip line is better for all concerned), we ripped ours and it has worked very well indeed, just simply didn't realise how well it would work; or you could plant rows of the tall clump like grasses eg.,. lemon grass/citronella grass, you will have 2 or 3 rows of plants staggered to form the swale as with the hay bails they will trap debris and act as a swale plus their root systems will give the key for the water to soak underground. the trench swales to me are more labour intensive to install and pretty much a permanent aspect of you landscape, where as all the other ideas can be temporary depending on your changing needs. from my observations if you have heavy clay soil using grasses or rips will work better as if you dig a trench in particular this willa ct more like a dam and the ability for the water to soak in may be restricted, just something to take into account. also with the otehr type constructions you don't need to be so exacting with constructing along the contours just a by eye level will do. len mail len lens garden page