It would be right even if the development of new technology were the only uncertainty confronting planners. Barring a complete breakdown in the present impetus of research and discovery, radical change in the technology of water supply and water quality control appears to be extremely probable within the next few decades. Some of the best of the emerging tools, there is reason to hope, may permit men to deal with water problems in ways that are more harmonious with natural ways and less structurally imposing than present methods. Possibly the present, often essential reliance on large storage reservoirs, for instance, is going to be modified, though how much the ultimate way of doing things will have to combine old and new technologies is something that cannot be guessed. If it cannot yet be guessed, it cannot be incorporated in a rigid plan, which has to deal in technological certainties--i.e. in present technology--and must therefore impose that present technology on the future, whether or not the future is going to need it. If we are right in believing that from this generation on, people are going to be increasingly jealous in the preservation of their natural heritage, future Americans will not be likely to thank this generation for having unnecessarily robbed them of choices as to how to handle the streamwaters of a superb river basin like the Potomac's. Any more than they would thank us for having done nothing at all and leaving them to scramble for water, and filthy water at that. Quite simply, no one has the right to do either of these things to them. It is our belief that if genuinely conservationist values are established as the ruling principles in a flexible, properly paced, continuing planning process, there will be no need to fear that future generations are going to be either stuck with large mistakes on our part, or cursed with shortages, floods, and pollution. With this report we hope to initiate such a process for the Potomac. [Illustration] [Illustration] [Illustration] II TOWARD A MORE USEFUL RIVER