And upon the emerging potency of this sound and urgent concern with the way the natural world is being used up, we believe a flexible form of planning can be based that will do away with the dilemma posed by the complexities and uncertainties of the moment. With a minimum of compromise, such planning will be able to identify and propose solutions for immediate problems in places like the Potomac Basin, while moving toward longrun solutions for other problems as those problems' dimensions become clearer than at present, and as technology and politics make better solutions feasible. Solutions for pressing and immediate problems have to be in terms of present possibilities--political, financial, and technological. Some such immediate problems--of water supply, pollution control, and scenic preservation--exist in the Potomac Basin and are analyzed in this report, and presently feasible action is recommended for their alleviation. A considerable part of the report is concerned with such problems, with the range of possible solutions for them and with our reasons for making specific recommendations. These immediate solutions do not constitute what has been called a "quick fix"--piecemeal, one-shot action to patch up things until another crisis arises. As much as possible, they have been worked into the picture of longterm Basin needs insofar as those needs can be discerned, and it is intended that action against future problems shall be built upon them. Furthermore, we have sought to maintain an ample view in identifying long-term difficulties and indicating what should be aimed for when it is essential to act against them. But we have not shaped a rigidly complete, prescriptive plan identifying exact measures for the cure of all present and future ills of the Potomac Basin. For a variety of reasons, we have concluded that such a rigid plan would not only be self-defeating in the long run, but that it is actually undesirable. We are aware that this conclusion is going to arouse criticism among those who during the past three years have consistently demanded that we provide a total answer, for the purpose either of unseating the governing principles of the 1963 plan or of reinforcing and amplifying those principles. Nevertheless we are certain that the conclusion is right. [Illustration]