Furthermore, even if all these doubts and areas of ignorance were to be easily resolved, insistence that the upper estuary is the only logical answer to metropolitan Washington's water problem ignores the fact that major water demands are building fast in certain already-mentioned areas of the upper Basin, and that, since the Basin is a hydrological unit, measures to satisfy these demands can easily, economically, and quite logically be designed to furnish a good part of the metropolis' near-future safe margin of water supply as well.
A need for vigorous research specifically directed toward exploring all these alternative means of supply is evident. If it moves fast enough and the knowledge that comes out of it is made available to planners, it may very quickly make a great difference in the kinds of sources of water they can turn to for the solution of problems, just as studies since the early 1960's, when the Army work on the Potomac was completed, have altered prevalent ideas about pollution control through flow augmentation, and have therefore greatly diminished the overall amount of water considered necessary to meet the Basin's demands.
In the crucial meantime, the established certainty of storage in reservoirs is available. In river basins with reasonable annual amounts of precipitation but with human demands on streams that sometimes exceed the rate at which water flows down, such reservoirs are still usually the most dependable and efficient item in the present technology of water supply. And since they generally have other purposes to which proportionate shares of construction costs are assigned in individual cases—flood protection, water quality control, navigation, hydroelectric power, recreation, silt detention, etcetera—they tend often to be the most economic sources of big quantities of water. In one form or another they have been built from very ancient times, and they have been indispensable to the useful development of water resources in our expansive economy.
In parts of the United States far from sea-coasts or large natural lakes, reservoirs built for water supply and other purposes have become the focus of enormously popular forms of recreation that would otherwise be impossible in those regions—sailing and motorboating and water-skiing and the sort of fishing possible only on big water, and such things. Properly designed and located, they can be beautiful bodies of water, as the vacation homes that grow up around many of them testify.
Strong objections to them also frequently are voiced. They are one of the most massive manifestations of man's technological ability to adapt natural processes to his use, and they sometimes have profound effects on fish and wildlife and the whole ecology of a stream system region, to the dismay of many conservationists. Often too they flood out large areas of riverbottom farmland and other private property, arousing the ire of some rural folk and small townsmen who feel that their interests have been sacrificed to the water or flood-protection demands of downstream city dwellers. Opponents of major dams sometimes assert that many of them have been built not to meet real hydrological needs but to foster economic development which may or may not materialize and may or may not be worth the loss of natural or scenic or agricultural resources disrupted by the reservoirs. Other thinkers, not necessarily against reservoirs in general, express a doubt that the potential effects of specific structures are always thought out sufficiently beforehand. Among these are the authors of a recent publication of the National Academy of Sciences—National Research Council, Alternatives in Water Management:
"We create great reservoirs that stop the migration of fish and then provide costly fishways, hatcheries, and other devices to maintain the fishery, and with no certainty of success. We impound water without knowing the effects of that impoundment on its quality. We build an irrigation project and then find salinity increasing dangerously in the river downstream. We eliminate high-flood peaks by reservoir storage, but downstream from some reservoirs we see unpredicted erosion, sedimentation, bank-cutting, and other effects, even unto, as in California, the loss of beaches along the seacoast, starved of their supply of sand."
The list of objections could be extended—and often is by objectors—to a point of pettiness. Nevertheless, the main doubts are gaining much acceptance and are imperatively having to be taken into account more and more these days, as new elements of water technology and philosophy—some of them mentioned earlier in this chapter, others to emerge in subsequent discussions—come closer to full feasibility and become a part of general human knowledge. Delay in building reservoirs until it is certain they are needed is on the verge of becoming a respectable element in planning, and in the future dams may well become merely one of many ways to guarantee water and handle it. At least some water authorities, though certainly not all, have voiced the opinion that most present reservoirs will some day serve primarily for recreation, if emerging new principles of water supply, water quality improvement, flood protection, power generation, and such things attain general use.
That day, however, has not yet dawned, nor is the interim before its arrival calculable. It is necessary to face present reality with present tools, and the reality at the Washington metropolis and elsewhere in the Basin is that a good deal of water is going to be needed rather soon, and that no reasonably economic alternatives with any clear esthetic and ecological advantage over reservoirs are presently available to furnish it.
Nor, if planners and designers are aware of the whole set of problems, do reservoirs necessarily have to be weighty in their impact on the natural scene and the public interest. The quantities of stored water needed for the Basin's near future are relatively modest in comparison to potential supplies, and a multitude of good reservoir sites exist to be chosen from. There is no reason why, with present knowledge, a minimum of necessary reservoirs cannot be planned and designed for a maximum of beauty and pleasure. It is a notable fact that a very large number of Americans prefer boating and fishing and other aquatic sports on reservoirs to any other form of recreation, and another notable fact that in the upper Potomac Basin there are very few places where even small numbers of Americans can thus indulge themselves at present.