water


I work at the Monterey Business Center in Yucca Valley, California, which is about 250,000 square feet of flat roofs and cement parking lot. I’d been wondering what all that would look like in a rain event and on August 29, 2013 I found out.

Monterey Business Center arial from Google Maps

Monterey Business Center arial from Google Maps

Jackie is not as excited about the rain as I am.

Roof water pours onto the sidewalk and into the parking lot

The parking lots have channels to direct water to the street

Onto the street

Down the street

Off the end of the street

Into a gully. (The blue-topped pipe in the gully says “water” on it. I thought that was hilarious.)

Down the gully

Flash flood in Yucca Valley on Make A Gif

And through the desert

pkvKsi on Make A Gif, Animated Gifs

Until it hits the berm of a road

Until it breaks through onto the road

And starts to flow down the road

This is where it ran out of steam. The water puddled up here and then mostly evaporated, “To rain again on someone else, east of us,” as Buck from Transition JT says. If there had been more water, it would have poured down this road and into a slightly more intentional gully at the end of it:

It would eventually hit the big wash in front of those mountains in the distance and flow east to the dry lake bed that is just west of Copper Mountain, maybe 18 miles away. That’s the lowest point in our watershed.

dry lake

Copper Mountain, Sunfair lake bed in front.

[animated gifs made at MakeAGif]
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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.

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:

photo (23)

photo (24)

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.

photo (25)

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

photo (26)

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

photo (27)

Down the sidewalk, into the street.

photo (28)

Down the street.

photo (29)

And into 50 feet of storm drains.

photo (31)

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:

Because it is so dry in Joshua Tree, water is great for cooling off. According to my calculus-free, 200-level physics education, this works because a tiny bit of the heat energy stored in our bodies is used up every time a water molecule evaporates. It’s almost like the water molecule uses our body’s heat to achieve escape velocity, to become a gas. A lot of water evaporating creates a significant cooling. This is how sweating cools us, if we’re lucky enough to be in a dry area.

So when it is hot, which is every day in the summer, we get wet a lot. Inside, we have spray bottles handy so we can spray each other whenever someone starts complaining about the heat.

Above the stove is the handiest place for the spray bottle.

Outside, we often hose each other off. A good drenching keeps us cool even on the hottest days, until we are dry. Granted, that might only be for 15-20 minutes on a really hot day, but comfort is worth taking breaks that often.

If we’ve stored up some heat from a bike ride or forgetting to hose off, we also have a stock tank in the yard for dunking ourselves:

Reanna, cooling off.

The water stays cool even on the hottest days, also because of evaporation, so it is always refreshing to take a dunk. I built the little platform so when we drain the tank, we can water our plants.

12-inch dirt-filled stock-tank platform with screen lid and hose outlet. This photo was taken before I put plank decking on each side of the platform so we don’t get our feet dirty getting in and out.

We also got a “swamp cooler” from our friends Mike and Sarah. It wasn’t big enough to cool their house, but it’s good for our trailer. Reanna sewed a sleeve to funnel the air into our back window, so we didn’t have to cut a big hole in the wall.

Swamp cooler, on home-made platform

Reanna’s sleeve, held to swamper with a drawstring

Sleeve, inside window, held open by a wire frame

It makes a huge difference. A swamp cooler is simple and effective: A pump pulls hot, dry air from outside through wet sponges, creating cool, moist air inside. The physics involved is similar to sweat-cooling, except the heat energy used to turn the water into a gas is drawn from the air itself.

It requires simple enough plumbing that I could handle it myself:

A splitter where our (lead free) hose feeds the trailer, fitted with a compression joint to attach copper tubing. You can kind of see the copper-tube cutter (red) at the bottom of the frame.

Another compression joint, feeding the float valve that lets water in when the level gets low.

Swamper, inside: The float valve (blue) lets water in. The water pump (green) pulls it up and pours it down the three sponges in the left, right and back (removed) walls. The fan (drum at top) pulls the air in through the sponges and pushes it into the trailer. Simple!

The most fun way to use water to cool off, of course, is swimming. My mom got Reanna and me a month’s pass to the pool at the Joshua Tree Retreat Center (AKA Mentalphysics) as a wedding present, and we used that quite a bit. It was awesome. Thanks, Mom!

Reanna at the JT Retreat Center. Note luxuriously empty pool.

Reanna & Rob at the Joshua Tree Inn’s Hacienda Pines pool.

Matt at JT Inn pool.

Backstroke race at the Yucca Valley High School pool, also open to the public in the summer.

Kids in Ken & Katie’s blowup pool.