Flush with success at having created a drainage problem, solving it by creating another, and solving that too, I am going after another drainage problem to the rear of the house. The runoff from the gutters empties on the bare ground, the better to ‘naturally percolate into the wetland,’ according to the City. However, there is a pretty good sized home between the runoff and the wetland, and so the water seems to naturally percolate across the patio, where a pool of mud, mulch, and debris forms at the base of the foundation until it spills over onto the soil. From there, much of the rainwater then runs the length of the patio base, pushing before it all the mulch that was laid down by the builder at the City’s request and leaving behind a hardpan arroyo that runs like a river when it rains. The remainder takes a slight jog to the left into a natural depression in the earth, puddling to about six inches deep and standing for days. This shallow well was heavily planted with what are now drowned twigs–with the exception of a couple Scouler’s willow, which loved the wet feet and remained so tender that they were pruned to the ground by my four-legged defoliant friends. The ‘natural percolation’ theory is a very good one, if you happen to not live in the house or don’t care whether the person who does gets their Plant Survival Bond money back.
I dug a couple inches down from the perimeter of the depression toward the center, removing the “convexity” to allow for a gentle slope away from the house. I used some of the excess soil to fill the arroyo at the patio base, ensuring that the water will want to go in the new direction; the remainder I mounded at the center of my excavation. It will form a “turtle island,” (horaisan or horaijima) as sometimes seen in Japanese-style gardens; mine will have a fairly literal turtlesque appearance (things like that are fun when you have a little kid around), and will be called the ‘Dirtle.’ The new direction for the runoff takes the form of a lightly sloped, shallow streambed that meanders more or less directly to the new swale, right through a partially buried tree stump. If my plan comes together, and I love it when a plan comes together, the rainfall should go around the patio, through the creekbed, over the stump waterfall, and into the swale. From there it can run into the wetland, the lake, and to the sea! Be FREE!
While the primary function will be stormwater redirection, the appearance will be similar to a small-ish Zen garden (Karesansui). Farther downslope will be the rain garden, a shallow depression in the native clayey dirt backfilled with more hydrophilic soil and planted with sword- and maidenhair fern and the iris-like native, golden-eyed grass (Sisyrinchium californicum); but the rain garden is for later.
Here is the bonus: when it rains, rather than looking out the window, gently sobbing and wondering if it will EVER be spring, I will have something pretty to look at. All of this seems a fairly reasonable use of the property.