permaculture

[Paul Wheaton <paul@richsoil.com>]

A big part of permaculture is holding water onto the land.  

I seem to recall reading somewhere that if you plant willows, they will drink 
a lot of
water.  But the amount of water that they contribute to the surface is 
greater than the
amount of water that they use.  

It would seem that all animals and plants are going to output the exact same 
amount of
moisture that they consume.  If the wind is blowing hard, then moisture could 
be pulled
from the soil, transpired and be taken miles away.  If the wind is not 
blowing, that
moisture will probably reappear as dew the next morning within a few hundred 
feet.  

So, if I get only 16.5 inches of precipitation each year, and I'm trying to 
come up with
a strategy to hold moisture, would a willow be unwise?