weather


I went to my first Transition Joshua Tree event, a rainharvesting workshop on April 28. It was fun and inspiring to meet with a good-sized group (maybe 20?) of neighbors interested in water sustainability in Joshua Tree. It was nice timing, too. Reanna and I just spent the previous day on the Desert-Wise Landscape Tour, looking at how local people are designing for low-water use.

The main topic was how to catch and store rainwater that falls on your roof. Our presenter, Buck, seemed to have quite a bit of experience installing gutters and catchment tanks, and thinking about water in the desert. He had a machine that made seamless gutters of any length out of strips of aluminum:

gutter maker

And showed us some tanks and filtration systems:

catchment tanks

One of the participants reported catching over 2,000 gallons of water in a four-minute “rain event” with one of these systems. While it is very dry here (less than a half inch in 2013 so far, I believe) it can rain really hard. In my 10 years in the rain country of the Pacific northwest, I never saw it rain half as hard as a big rain in Joshua Tree. So you can wait a long time for a rain event but you want a large storage capacity when it does.

We want to catch as much of the water as possible because we are using up our aquifer about 10 times as fast as it is replenishing. (If it is replenishing, that is–there seems to be some controversy about it.) Water that runs off of our roofs flows down washes to the dry lake in Sunfair, where it mostly evaporates, and eventually rains on someone else downwind of us. According to the conservation representative from the Joshua Basin Water District in attendance, we use 151 gallons per person per day and sustainable use is under 15. She talked a bit about two plans to replenish our aquifer using technology: One, under way right now, is piping in northern California water from the Hisperia aquaduct down into our aquifer. Another, under study, is diverting the Quail Springs wash from the surface (and the dry lake) underground. I’m not sure what that will look like–I picture a 600 foot hole in the middle of the wash, with caution tape around it–but at least it would be using our own water.

Living on less that 15 gallons of water a day looks to be tough. Here’s an essay by my sister-in-law, Maya, about going from 420 gallons per day to 50 gallons a day, with a toddler and while continuing to grow food. I’d like to visit each person who came to the workshop and see what systems result in what level of water usage. Because Reanna and I share a water main with my family, I don’t know how much we are currently using. I will figure it out and write a post about it.

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I just visited my brother Ely in Glendale and the forecast was calling for rain in the next couple days. He was happy about that. They need the water. Glendale gets an average of 21.09 inches of rain a year (according to Wikipedia) and had only 16.95 inches in the last ten months (according to Weather Underground). Ely just emailed me that a meteorologist on the radio today said they’ve only gotten 5.15 inches so far this year, 9 inches below average).

But what is going to happen to that rain water? Almost all of it will fall on rooftops, sidewalks, parking lots and roads:

Glendale

For a case study, I looked at Ely’s neighbor’s roof. They have a gutter on the low side, which will catch most of the rain that falls on that roof:

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The neighbor’s gutter dumps into a drain pipe that heads towards the street on Ely’s side of the wall, picking up the runoff from another roof along the way.

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Back on the neighbor’s side of the wall, the pipe dumps on the ground.

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The water runs along the wall, down onto Ely’s yard, and onto the sidewalk.

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Down the sidewalk, into the street.

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Down the street.

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And into 50 feet of storm drains.

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Verdugo Wash

The drain dumps into the Verdugo “wash,” a giant concrete culvert a few blocks away.

Los Angeles River

Which is a tributary of another, even bigger concrete culvert, the Los Angeles “river.”

(photo by Ron Reiring

Which dumps into the Pacific Ocean at Long Beach Harbor. (photo by Ron Reiring)

The system moves the water that lands on Glendale to the ocean quickly and efficiently. Meanwhile, they wash their cars and water their lawns with water pumped in from the distant Colorado River.

Here’s a totally different way of thinking about rainwater, from another, drier city that also relies on the Colorado River–Tucson, Arizona. Watch for the wow moment, starting around 1:20:

Reanna is from the Pacific northwest and I grew up in Joshua Tree, CA, where we are currently living. We have an ongoing conversation about humidity here because having grown up in a wet climate, she is vigilant for the ways that moisture in the air decomposes things. “If we don’t keep it warm in here, won’t condensation damage the books?” No, it won’t, and probably wouldn’t even if we had a constantly boiling pot of water. The only place I’ve ever seen mildew in Joshua Tree is in one of our bathrooms which, until very recently, had no windows and no fan. This was not aggressive mildew either, just noticeable every once in a while. “If the roof of the trailer has leaks, won’t there be tons of mold in the walls?” No, not likely, because even if rain was pouring right through the trailer, it would be completely dry again within hours.

I have never tracked humidity levels before, so while I knew that Joshua Tree was dry, I didn’t know what level of humidity qualified as dry. I also didn’t fully understand the different measurements of humidity that are floating around out there. The short version of that story is that there are three units of humidity: absolute, specific, and relative humidity. Absolute humidity is grams of water per kilogram of moist air and specific humidity is kilograms of dry air. Relative humidity is more complicated. If I understand correctly (if incompletely) it is the ratio between 1) the pressure that the water vapor in a given amount of air would exert on the insides of a container, should it somehow be trapped there without its accompanying dry air, and 2) the pressure below which water would start condensing out of the air. Relative humidity is the measure of humidity that you usually see in weather reports, partly because it takes into account temperature–at lower temperatures, air holds less water.

Here are some cities with different levels of relative humidity, to give a sense of where we are in Joshua Tree. I’ll also include precipitation. (Data is from Weather Underground unless otherwise noted.)

Seattle, WA, 2011: High 99%, Low 34%, Average 82%, Precipitation 12.92 inches

Honolulu, HI, 2011: High 96%, Low 18%, Average, 65.6% Precipitation 23.82 inches

Joshua Tree humidity, 2011: High = 83%, Low = 10%, Average = 30.7%, Precipitation 1.53 inches

Las Vegas, NV, 2011 (the driest city in the US): High 98%, Low 2%, Average 28.7%, Precipitation about 2.5 inches (precipitation according to climatestations.com)

Kolkata, India one of the most humid cities in the world, on July 15, 2011: High 94%, Low 64%, Average 84%, Precipitation 0.0 inches

And Kartoum, Sudan (Sahara desert), on January 4, 2011: High 43 %, Low 10%, Average 24%, Precipitation .51 inches

Nathen, Reanna, Quilt, Desert

It’s the middle of summer, in Eugene, Oregon, the place and time with the best weather I’ve ever seen, and that includes Maui, southern California, and the San Francisco Bay Area. It’s just really nice all the time. I’ve noticed, though, that people who live here don’t seem to appreciate it. We spend all winter griping about the cold and the rain and then most of the summer griping about the heat. The thing is, it never really gets cold or hot here. It only gets cold enough to snow a few times each winter. I lived with Max Orhai, who is from Montana, through my first winter here and he liked to say “You call this winter?” and walk around in T-shirts. And this week is projected to be blisteringly hot: in the mid 90s. (Canadians, 95F = 35C.) Where I grew up, in the Mojave desert, it doesn’t drop into the 90s until well after sundown, and it is a blessed relief.

I think part of it is that these moderately hot temperatures do not force us to learn to act appropriately during the heat of the day. 105F is like an oven if you’re trying to do yard work (without dousing yourself with the hose every fifteen minutes, at least), but it’s actually pretty pleasant sitting quietly under a tree, mostly unclad, with a cool drink. And each little breeze is a wonderful experience.

But we also acclimate. One summer in the Bay Area I remember hearing that people had died of heat stroke during a temperature spike that got into the low 90s. They weren’t just griping; their bodies got too hot. And I remember my first day on Maui: My friends and family took me on a wonderful, balmy, lightly clouded hike through the bamboo forest, complaining and apologizing the whole way about the weather. I had left Joshua Tree in February, with early mornings in the 20s (Canadians, 25F = -4C), and here it was in the low 60s and everyone was miserable but me. (Los Angeles is the same. When I visit my brother Ely, he will apologize about the weather if there is a wisp of cloud in the sky—this in the winter, when I probably haven’t seen the sun in weeks.) In six months, of course, I was the same way. I was embarrassed, but almost any variation in temperature was uncomfortable. 80F was oppressively hot and 60F had me shivering.

As for Eugenians, and maybe Pacific Northwesters, let’s get our act together. As I see it we have two options. 1) Admit that these 90+ degree days are perfectly normal around here, and are exactly what we were craving all winter and enjoy the heck out of them. 2) Admit that the only season we can actually enjoy in this region is spring, not because the weather is more pleasant, but because the ongoing dismal winter weather makes it easy to appreciate the occasional sun and relative warmth.