2006-12-27

Rainfall for 2004-; front yard meadow

We had 0.26" of rain last night, according to the rain gauge in my back yard. I've been measuring rainfall since fall of 2004 and I've been using the same old sheet of paper to write the totals down on, which doesn't give a whole lot of insight into year-to-year variations. Today I decided to innovate and graph them all up using Excel. Unfortunately, at this time I can't make Excel overlay the 2004 and 2005 winters in graphical form, for comparison to this winter. I'm certain that this would be a trivial operation in some more competent graphing program.

Until I solve the graphing problem, I'll just note that in the 2004 wet season (officially July 1 to June 30, but I use Oct 1 to May 31) I had about 7.4 inches at the end of December, with a seasonal total of about 29 inches. By contrast, in 2005-2006 I had only 1.4 inches by the end of December and just over 10 inches for the whole season. This year we stand at about 3/4 inch as I write, less than in both previous years. However, I think that there's a high dispersion in rainfall totals, as well as the timing of its arrival, so I wouldn't conclude that we have any sort of trend based solely on the current 2+ years of data.


UPDATE: Obviously, I've solved the Excel problem. As usual, click for a full sized version. Average annual rainfall for the past 60 years at the official Los Angeles measuring point is 12.24 inches (link). I've also determined that the 60 year monthly standard deviation in rainfall actually exceeds the average in many months. Using the usual propogation of errors, I see a plus or minus 5.15 inches at the end of an average rainy season. Assuming that monthly rainfall is normally distributed, this means that about 68% of the time rainfall totals will be between about 7 and 17 inches (12-5 to 12+5).



I've been keeping an eye on the rainfall this year because I wanted to plant my front yard native meadow coincident with the rainy season. I sowed the seeds yesterday (festuca rubra molate, red needle grass, yarrow, blue-eyed grass, two types of clarkia, poppies, some local fuchsia, and others - full list later when I can retrieve it) because we were expecting rain: So far, so good. Unfortunately, I have to be away for several days since my house is tented (as of today) for termites and we're looking at sunny weather for eight days or so. I fear they may sprout, dry, and die by the time they get more water.

The front yard meadow is about 350 square feet of former turf lawn adjacent to the sidewalk. The rest of the front yard lawn had already been removed to make way for other natives and Mediterranean plants. For the meadow, I scraped the earth into a carefully sculpted hillock that runs the length of the yard to give my otherwise flat yard some texture, to allow for different soil dampness levels (the meadow area only has sprinkler irrigation), to provide an on-property low spot for water retention, and to avoid having to haul away the excess soil. The low hillocks are liberally larded with the (hopefully) dead remnants of the lawn, so they will have quite different drainage and fertility than the adjacent "low lands". I killed the lawn and had it scraped back in September. Following that, I graded, sculpted, sifted and watered it, raising a fine crop of latent weeds from the seed bank. These were subsequently poisoned with Round Up. The whole process was then repeated again, with less of the grading and more of the watering. By Christmas I figured that my long suffering neighbors had waited for me to get to business long enough.

I have always been cautious of the eventual curb appeal of the native garden and have tried for a more tended look than the nice couple in the next city over who were told to cut down their weeds (referring to the native plants). I think that a meadow of wildflowers mixed with perrennial grasses might be acceptable to the greener grass through chemistry crowd.

UPDATE: The termite folks trampled all over the meadow, even after I pointed out to them that I'd just seeded it. I don't know how this will affect things. They also dissappeared a new planting that I'd protected with a pair of stakes and which I'd also pointed out to them.

1 comment:

  1. While the rain season officially starts in the fall, the wettest weather usually arrives in Feb and March. With the weak el nino setting up, you have a slightly better chance than average for rain this spring.

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