All of these things, and others as well, have to be considered together as parts of a whole problem. And that problem is that men's hugely increasing numbers and their multiplying technological power over their environment have made it necessary to readjust the balances somewhat in great natural units like river basins—to restore, manage, and protect them in such a way as to be able to hand them over decent and whole and useful to the people who come after.
Problems of Water Supply in the Potomac Basin
Wisely handled, the water that runs annually through the streams of the Potomac river system can be counted on to satisfy any demands that people there are likely to make on it in present times or during the foreseeable future. More than 2½ trillion gallons of fresh water normally flow down the Potomac in a year. It would be pleasant to believe that this means that the natural and unassisted river system is going to continue to serve human needs in the future as it has served them heretofore—that after cleaning up the network of streams and ensuring against their repollution and the desecration of their landscape, men will be able to leave them respectfully alone to run down toward the Chesapeake Bay as they have run during and before human memory.
However, it is not so. Whatever human population might be considered ecologically tolerable under natural conditions for the nine million or so acres of earth, rocks, vegetation, and water that make up the Basin, it has long since been exceeded by hundreds on hundreds of thousands. And if those who predict such things are right, it is going to be exceeded much further in the near and middle future. Today's approximately 3.5 million Basin inhabitants are expected to double by the turn of the century, with accompanying complex shifts in the ways they will be making their livings and in the numbers of them who will live in the country as compared with the cities and towns. Thereafter, further geometric increases are contemplated, calmly by some contemplators and less so by others.
As a result of past and present populations and their activities, conditions in the Basin—including the river system—are necessarily far from natural, for specific structural development is not the only form of change. The Potomac environment has been adapted to man's use, and in places where that use has been unreasonable it is already in trouble. Clearly it is going to have to be manipulated artificially to some extent to meet people's demands on it and to guard it against the worst effects of their numbers. In fact, very luckily, it already is being so manipulated in dozens of ways ranging from methods of farming and forest management to sewage treatment. It is possible to hope that present population forecasts may somehow find less than ample fulfillment, but it is not possible to count on it for planning purposes. Nor is it possible to wish out of existence situations already serious.
WATER SUPPLY POTOMAC RIVER, WASH. D.C.
GROUND WATER LEVELS WASHINGTON, D.C. AREA
At times during the hot months of drouthy 1966, the climax of a dry cycle that had begun to develop five years earlier, the Washington metropolis was not too far from the bottom of its water barrel. The situation was not as bad as in some other Northeastern regions, nor as bad as some local analyses claimed, but it was bad enough. The highest daily withdrawal of the year was on June 26, when the metropolitan water intakes in the Potomac sucked out approximately 380 million gallons. Of this some 30 million gallons had to do with a pumping pattern pertinent to adjustments within the system, and the other 350 million went for the use and refreshment of a metropolis afflicted by summer's heat. The total figure represented less than half of the river's flow at that time.