Hydrology: A Question of Birthright

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Constant Resource. Back of all such experiments is the inexorable fact that the supply of water is limited. The earth has exactly as much water now as it ever had: no less, but no more. Unlike any other resource, the 326 million cubic miles of water are not used up. In nature's familiar, never-ending cycle, water falls to earth as precipitation, seeps underground, flows into lakes and streams, and rushes toward the oceans. Sooner or later, it evaporates back into the air or is given up by plants in the process of transpiration. An acre of corn gives off to the air about 4,000 gallons of water each day. In time, the water returns to the earth again in the form of rain and snow.

Precisely because the vast but limited supply is indispensable, water has inevitably aroused bitter disputes; the very word "rival" was used in Roman law as a term for those who shared the water of a rivus, or irrigation channel. The U.S. Supreme Court last year had to settle a longstanding feud between Arizona and California over use of the waters of the Colorado River. Continuing Mexican complaints have finally persuaded the U.S. to agree to dig a canal to divert salt-polluted waters from Arizona irrigation runoff before they can re-enter the Colorado and flow past Mexican cropland. But diplomacy has not yet managed to move the Jordanians and Israelis to settle their quarrel over who should divert how much water and where from the Jordan.

Whatever their water problems, whatever sends them out to squabble with their neighbors, more often than not cities and nations have only themselves to blame. They squander their supplies in haphazard irrigation, pollute their readiest sources, and are casual about preparing for dry years. In 1950 a research team warned New York City that it would need additional water by 1970, recommended the installation of meters* and stringent measures to stop leakage in the aqueducts and water mains. A pumping station was built upriver on the Hudson, then dismantled as soon as the 1950-51 emergency was over. Nothing was done about meters, and the city still loses at least 30 million gallons of water daily from leaks. Now, after a fourth straight year of drought, New York's reservoirs are down to 36% of capacity and still falling.

Living in Filth. New York's lack of foresight is no exception. Most of the major waterways of the world have become cesspools of progress. In medieval Paris, the streets were open sewers, but the Seine flowed so clearly that from the bridges it was possible to see fish swimming among the stones and green plants on the bottom. Today, after an energetic cleanup campaign, the streets are clean, but the Seine is murky and grey, except for the occasional white fluff of detergent suds. Once England's M.P.s fished for salmon in the Thames at Westminster. No more. In Poland, the Vistula's filtration system is clogged with silt and scum, and Warsaw must tap other water sources. Sickest of all the Great Lakes, Erie is so close to dying that the states along its shore face the prospect of paying a billion dollars apiece for pollution control.