Riding the Storm Out

The lead editorial in Thursday’s LA Daily News urges “folks (to) take the matter (of collecting storm water) into their own hands.” This is a topic that could be difficult – if not impossible – for the “rugged individual” to tackle on his/her own. And a host of government regulations would probably prohibit any such action.
The basic premise for the editorial is sound: a lot of water actually falls as rain in southern California, but most of it goes out to sea; why don’t we just catch the runoff? The simple answer is that if it was cheap and easy, everyone would already be doing it. So what are the problems with this idea?
Let’s say you’re an average SoCal suburbanite, with about a quarter-acre lot. Your family with 1.5 kids and assorted pets consumes about 0.5 acre-feet of water per year. Average rainfall is a little over one foot, so “your” rainwater amounts to 0.25 acre-feet – or about one-half of what your family needs. Not a bad start.
Almost all of the rain falls in about a 4-month period, from mid-December until mid-March. In a best-case situation, you need to store 8 months of rainfall somewhere at your house. How big a tank do you need? About 50,000 gallons. And how big is that? About 20 feet in diameter and 20 feet tall. This should make a fine addition to every house in your neighborhood!
In short, this is – if you’ll pardon the expression – a pipe dream. But the concept remains valid. How much water from a great series of storms like we had last week is actually “wasted” by flowing directly into the Pacific Ocean? If we could capture and store any of that huge volume, it could help to offset the chronic water shortages that we experience here in the desert.
There are actually a few projects that have been underway for some time that do this – on a large but still limited basis. In fact, one agency has this as one of its main missions: the Water Replenishment District (www.wrd.org) – and they’ve been in business for over 50 years. So this is hardly a new idea.
But the math discussed above is the same on a regional basis as it is on a household basis: huge reservoirs are needed to capture the high instantaneous flows that these storms bring us. And where might we locate these reservoirs? “Not in my back yard!”
Could we drink this water directly? No way! So now that we’ve stored these vast quantities, we need to build treatment plants that meet the requirements of the Surface Water Treatment Rule – not cheap. And we need to staff, operate, and maintain these plants.
This is typical of what happens to so many otherwise-good ideas. Practical considerations, cost, location and NIMBY issues, water quality regulations, etc., present us with significant challenges. And a well-intentioned editorial from the LADN is not enough to overcome these challenges. Like I said, if it was cheap and easy, everyone would already be doing it.

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