Exporting Water

Water supply problems of the western states are increasingly in the news. These problems can only worsen as larger populations demand an increasing supply of water and as deep-well pumping depletes water reserves carried in underground aquifers.

Major rivers such as the Colorado and the Yellowstone figure in the discussions of water supply because of the large volume of water these rivers carry across several states. Together these two rivers carry about 20 million acre-feet of water annually (an acre-foot is one acre covered by one foot of water).

As the western states grow more prune-like, Alaska and British Columbia probably will be increasingly eyed as potential suppliers of fresh water. The day may come when these political entities will have to decide whether or not to export water, and it is possible that they will have no choice in the matter.

What would be involved in exporting 10 million acre-feet of water each year, an amount comparable to the flow of a major western river? Suppose that there were a means to collect a part of the rainfall from a portion of southeast Alaska or British Columbia the size of the Queen Charlotte Islands, about 4,000 square miles. Considering the huge rainfall in these areas, it might be feasible to collect four feet of the annual rainfall without it even being missed. Such collection would yield 10 million acre-feet of water.

To carry the 10 million acre-feet of water south at a speed of 5 mph would require a pipe 48 feet in diameter. This is a large but perhaps not impossible object. And while being this fanciful, why not suggest the additional use of it as a flume in which to export another renewable resource, trees?