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.