From Shining Sea to Land

Facing a global threat of a shortage of clean - drinkable - water, we are looking at where we are in the United States, and where the best ways to go might be.

We reported last time that the United States consumes, on average, some 345 billion gallons of fresh water every day. At the same time the US average daily precipitation is 4.2 trillion gallons. So what’s the problem?

Well, to begin with, water supply and sanitation in the United States face water scarcity (locally), pollution, investment problems, concerns about the cost of water for the poorest and changes in climate.

Rainfall in both variability and intensity is expected, as a result of climate change, to produce more severe droughts and, ironically, more flooding which in turn could cause serious problems for the water supply and most serious consequences for pollution from combined sewer overflowing.

Actually, the US receives enough annual rain/snowfall to cover the entire continental US to a depth of 30 inches of water. This amount is called the United States Water Budget. Of the 30 inches, 21 inches return to the atmosphere by evaporation or by a process called transpiration whereby water passes through trees and grass from roots through to the air. (Example: one tree transpires 50 gallons of water per day).

The eastern half of the country receives quite a bit more rain/snow than the west. This is due in part to the annual rainfall differences between the various states. And this process presents some interesting situations:

The most severe droughts occur in parts of Texas, California, Florida and, to a lesser degree, Georgia. So can it be a coincidence or a happy gift of nature that these drought tendency areas are also on the shores of oceans? Those same oceans that cover 70% of the earth?

In any event, it is no accident that within the next 10 years many coastal areas in the three states mentioned above will be making desalination of seawater a serious portion of their water supply. And further, the technique of membrane technology will be used in steadily increasing measure for groundwater and recycled water treatment as well as use by industries to remove impurities and potentially toxic contaminants in their effluent and for the production of ultra pure water.

And the story of using inactive warships as desalination plants here and anywhere else in the world will be the subject of another blog. Also conservation – more power to the people.