ts 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 2-1/2 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