[Greenbuilding] quick tools for calculating rainwater run-off?

[Chris Koehn]

Erin,

You're in Portland OR? 
Up the coast on Van Isle, we have several red cedar (thuja plicata) trees in our yard. We're told by arborists that at 35 years old they suck up an average of 200 gallons of water from the ground daily. Each. 
Folks who remove red cedars willy nilly without understanding this often end up regretting it when the hydrology of their site changes suddenly, resulting in run-off and wet basements.
Might want to incorporate one of these into your scheme if water removal is one of your goals.

Cheers,

Chris Koehn
TimberGuides Design & Build