Water Watch, a company that combines satellite technology with analytical algorithms to measure water consumption (ET less precipitation), cropping efficiency and a number of other important indicators of human and environmental activities.WW is heavily involved in the "more crop per drop" movement that focuses on reducing over- and under-irrigation (whatever the technology) while maximizing yield.
Water Watch started in the Netherlands, but they do a lot of survey work around the world (China, Saudi Arabia, Brazil, etc.) -- click here for a clickable map linked to their projects.
I was pleased to hear that WW is in discussions for a big expansion of its services. We need LOTS of data on water use. Listen to our 45 minute talk [18MB MP3]
Bottom Line: What gets measured gets managed.