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April 02, 2006
Water Wars
In 1912, Owens Lake was a large, blue salt lake covering 100 square miles. During the late 1800s, a steamship crossed Owens Lake to carry lumber, mine timbers, charcoal and other supplies to the east shore, where it was packed up to the Cerro Gordo Mine near the crest of the Inyo Range. On the return trip the steamer carried hundreds of bars of silver bullion to Cartago Landing at the south end of the lake, saving days of freight time by mule trains. Today as you gaze across the immense, rose-pink salt flat, it is hard to imagine that this was once a beautiful blue lake with a busy steamship and two bustling ports at distant shores.
What happened? The Los Angeles Water Wars.
Recently, with heavy rains, we’ve had near rivers washing down our street. So I asked myself, could Los Angeles collect enough water to be self-sufficient? Could we?
The two things to determine: (a) how much we could collect from our rooftop and garage; and (b) how much we use each day. The formula for collection is available from the State of Texas, and equals:
(1) Rainfall in inches
(2) times: Collection Area (square footage of house and garage)
(3) times: .67 gallons per inch of rainfall
(4) times: system efficiency of 75% to 90%, based on whether the roof is rough or porous, or smooth and designed for water collection. I used 75%.
I calculated that we could collect about 10,000 gallons per year. Unfortunately, when I added up the bills from the DWP, we use at least 12 times that much per year. In fact, at the average water-thrifty rate of 49 gallons per day per person, we could collect only one-third of our indoor water. (Not including the garden irrigation.)
We could collect 100% of our indoor water needs (excluding the garden) only if we had a much bigger collection system, composting toilets, and never bathed. Also, this would require installing an expensive storage and decontamination system.
Not that water collection isn't a good idea ... just that the Bob & Sue Self-Sufficiency Plan A would be a wee bit lean and stinky.
Posted by Sue at April 2, 2006 08:29 PM