L.A. wasted most of the 20 billion gallons of rain that fell this week

As happens in each of the rare instances in which a strange liquid falls from the sky on to unsuspecting Angelenos (people in other parts of the country call it “rain”), those who understand this region's water predicament (we're running out of it) have two simultaneous reactions:

1) Perform a celebratory rain dance, and

2) Wonder if this rain helps as much as it could.

To the second point, the reality is that Los Angeles squanders about 80 percent of its rainfall, pushing most of it into storm drains and out into the ocean. Since Sunday, Los Angeles has been blessed with two rainstorms that dumped somewhere around 20 billion gallons of water on Los Angeles County's 469 square miles (this is an approximation as rainfall amounts differed from location to location). But because the county is so heavily paved over and because we don't have enough storage infrastructure to capture the rain and filter it down into a natural aquifer, four out of every five gallons that fell drained into sewers and out into the Pacific Ocean in order to prevent flooding. What a shame, especially when an alternative is available.

In a brief email exchange with Andy Lipkis, founder and president of TreePeople, an environmental group that (actually)