Over the past couple of days, drought-stricken Los Angeles received about an inch of rain. But because so much of the Los Angeles area is paved, more than 3.8 billion gallons of that fresh rainwater was flushed into the L.A. River and out to the Pacific Ocean, carrying pollution and toxins along the way. As Southern California faces a sixth year of severe drought, we can’t afford to waste this precious resource. The new climate reality demands that Los Angeles get water-smart — and fast.