This is scientific American 60 second science. I'm Christopher Intagiyata.

When California was strangled by drought, the city of Los Angeles was offering homeowners cash to replace their lawns with landscaping that was less

thirsty because water just evaporates from over-watered lawns but how much?

So that turned out to be a lot of water.

Diane Pataki an ecologist at the University of Utah.

Turns out to be 70 billion gallons of water in year.

Pataki and her team got that number using a combination of real world

sensor data and modeling.

And they found that of water wasted specifically in urban landscaping,

lawns were to blame for three quarters of it,

with LA's six million trees accounting for the rest.

The study also uncovered something

these ecologists were not expecting to study, economic disparity.

The amount of vegetation is really

That means that wealthy neighborhoods actually have twice the evapel transpiration of poor neighborhoods

Meaning low-income neighborhoods not only miss out on the greenery, but also the natural built-in cooling effect of a VAPO transpiration.

The findings are in the journal Water Resources Research.

Finally, if you think native trees are the solution to water waste, think again, Pataki says.

Some of the highest water users in LA are those species, including the native California sycamore, is a very very popular tree.

The reason being that Southern California doesn't have a lot of native trees

except alongside rivers meaning their water guzzlers by nature.

Better she says to plant other species that thrive in Mediterranean climates,

...