Possible Answers
Except for acid mine drainage, most of the Basin's main problems are found at metropolitan Washington. Because they are primarily people problems and more people live there than anywhere else, the problems tend to be bigger, including that of water supply. A conceivable shortage of several tens of millions of gallons of water per day within the near future is not a small shortage, and small measures are not going to cope with it.
A number of possible measures have been considered and weighed. Some seem undesirable for one reason or another, even in terms of the distant future. Others are unusable now, but have promise for later, when more is known, or technological processes involved have been perfected, or cost have been brought within reason. Still others, undoubtedly, cannot even yet be discerned. And some will work now at prices that can be paid. Ultimately, it seems certain, the super-Metropolis of the future will depend on a mix of sources for its water, getting part of it by one means and part of it by another and so on, as technology makes new means possible, and as economy, safety, and other factors may dictate. Therefore, there is no single "right" answer for the long run, and an attempt to prescribe one inflexibly would compound confusion over the years and undoubtedly perpetrate an injustice on future citizens in ways already mentioned. We need to do them the favor of believing that they will be able to cope with their own immediate problems at least as well as we can do it for them, and probably in ways better suited to their tastes.
Nevertheless, it is imperative that the city be given a margin of drought insurance for two decades or more, and for this margin some source definitely feasible in present terms must be identified and guaranteed.
Going outside the Basin for any significant part of the metropolitan water supply does not appear to be justified. Some water is presently being drawn from impoundments on the Patuxent just north of the city, but no more of it can be counted on. Diversion from the voluminous Susquehanna much farther north is feasible from an engineering standpoint. But the cost of it would be relatively high, and there are also certain strong objections in principle, based on the facts that the Potomac does have plenty of water and there is no inherent moral advantage in transferring the question of development elsewhere, that the Susquehanna Basin may well need its own water at some future time, and that the ecological effects of such diversion on the immensely valuable fisheries of Chesapeake Bay, which are dependent in large part on a shifting balance of salinities maintained by the tributary rivers, are unclear.
"Planned scarcity" of water in a community, wherein administrators and public alike accept the certainty that during dry times lawns and parks and golf courses and sometimes human skins will have to do without the application of water for a spell, is a reality of life in some arid regions and is probably always going to be. Elsewhere it is, or should be, an element in the design planning of industries that use heavy quantities of water for cooling and such processes. All water supply planning must consider it, for to build against any conceivable shortage would be prohibitively expensive. Pricing of water so as to cut down on waste without curtailing ample legitimate use may well be a longrun tool, as has been suggested. But in terms of general municipal and industrial water, any great degree of calculated shortage hardly seems appropriate for a humid-zone city which has a fine river at its doorstep and happens also to be the national capital, so that a scarcity would be of national concern in a number of ways. Federally established and maintained parks and open spaces, for instance, with their carefully tended vegetation, would be one of the first things to suffer.
Desalting of sea water, another reality now in arid zones and one of immense importance, has a certain degree of planned scarcity built into it by way of its price, at least at present. Some people believe that in time this process will be refined to the point that it can furnish abundant cheap water to all the world's seacoast cities. Certainly as it develops it may well have a potential for marginal drought-proofing at Washington, an emergency source to be drawn upon if needed. But the day seems distant when it will be truly competitive in price with riverine sources in regions of adequate rainfall.
Inland arid regions and perhaps other places as well are undoubtedly going to find one answer to water shortages in the recirculation of their treated waste waters through municipal systems. In one form or another such recirculation is already working at certain places in the United States on an emergency basis, and its full potential for industrial use has yet to be explored. However, the indications are that towns' and cities' reliance on it during anything but temporary emergency conditions is going to depend on expensive methods of refinement and "fail-safe" overdesign, plus dilution with new water, which means again that it will probably not be competitive in price with natural water where enough good natural water can be had. To this may be added the observation that the consuming public presently has a few definite lingering qualms about the idea involved, particularly if there is other water around.
The underground rocks and sands of the Basin hold huge reserves of water with a fundamental relationship to the whole river system, whose basic dependable sources lie in these aquifers' outflow to the surface. Around the metropolis, some ground water is being taken from wells even now to supplement the overall supply and to satisfy the whole demand of any number of outlying communities. Though locally available quantities are limited and pumping costs rather high, such wells will undoubtedly be highly useful for future extensions of the metropolis, especially into the Coastal Plain.
There is also much promise in studies of the Basin's aquifers being carried out by the U.S. Geological Survey to determine detailed patterns of their contribution of water to the stream system and to see if it can be regulated and made even more useful. Such a possibility has great implications in terms of augmenting river flows both for water quality control and water supply, and could mean much at Washington. So could certain techniques of deliberate drawdown of aquifers to induce recharge with excess surface waters or sometimes treated sewage effluent, also presently under study. Ground water as a source has some unique advantages—among them a minimum of evaporation loss, less need for surface structures, and protection against catastrophic contamination—and it deserves full exploration, though it cannot at present be counted on as a significant part of the answer for the metropolis.
Far out, though possibly not very far off in time, is the likelihood that future water planners will be able to count on some degree of control over a given region's rainfall and snow. Through experimentation, this subject is rapidly being excised from the mists of superstition that once surrounded it, and the Department of the Interior has an active program of research and study in the West, with tremendous implications. But, yet again, present planning cannot take it into account except in the sense that, along with some of the other technologies already mentioned and undoubtedly others that have not yet even emerged to view, it adds to the near certainty that future planners are going to have a much wider range of alternative methods at their disposal, to choose from and mix as may seem best. And this, in turn, reemphasizes the wisdom of flexibility in present planning and the need to keep big irreversible decisions to a minimum.
The upper Potomac estuary from Little Falls down to the vicinity of Marshall Hall and Mount Vernon or below contains a great deal of fresh water, an accumulation made up of inflows from the river above the Fall Line, local storm runoff and tributary flows, and treated sewage returned to the tidal river. The volume of this water that would be available for use without salinity has been variously estimated. At low tide, there would be 9 billion gallons of fresh water in the upper estuary from Chain Bridge to the mouth of the Anacostia River; In the 10 mile stretch from Chain Bridge to the District of Columbia's Blue Plains treatment plant, 15 billion gallons; and, from Chain Bridge to the saltwater front near Indian Head, Maryland, 100 billion gallons. Most of the time now it is afflicted with heavy pollution, as will be detailed in the next chapter of this report. But it does constitute a large natural reservoir of potentially usable municipal and industrial water, whose attractiveness for these purposes, as well as for all others, will grow steadily as the pollution is brought under better and better control. These facts have led some opponents of any and all major reservoirs in the Basin to conclude that the water in the upper estuary is a presently satisfactory reserve with which to face any foreseeable metropolitan shortage of supply from the upper Potomac.
The assumption has strong appeal, but it appears to be too risky to serve as a basis for adequate present planning to meet looming demands. That even now the water in the estuary's uppermost reaches, above the main metropolitan treatment-plant outfalls, would be usable for short emergencies by the installation of relatively simple pumping equipment below the falls, cannot be doubted. That in the long run the major part of the freshwater tidal river at and below Washington is likely to be a valuable source of metropolitan water, maybe a principal source, is quite possible. Its use is and will be a strong consideration in longterm planning—another good reason, in fact, for flexibility. But the truth is that right now enough doubt and ignorance exist in regard to its exact potentiality that it should not be counted on to provide a safe margin of supply under all conceivable conditions during the next twenty years or so, for which planning provisions need to be more rigid and definite.
The doubts and unknown factors have to do mainly with the quality of this water, which comes under discussion later. In abridged summary of relevant facts at this point, it may be observed that unless all sewage and sewage effluents were collected and diverted to points well beyond the limits of the upper estuary, use of its water for periods beyond a few days of emergency would become essentially a form of recirculation of waste waters—with, at this time, the main drawbacks that we noted in regard to that process and certain others besides. For, under the low-flow conditions that would bring about its use, the effluents in the river below the mouth of the Anacostia would penetrate upstream as water was pulled out below the falls and would reach the pumps in fairly short order, probably moving in a tongue up the main channel.
With the radical improvement in the functioning of the metropolitan treatment plants that must be achieved, and other measures to relieve pollution in this part of the river, valid objections to such recirculation will of course weaken and ultimately disappear. But no one can reasonably expect that these things are not going to take a certain amount of time—quite conceivably enough time to run the city up against an emergency it could not handle without other, more standard sources of auxiliary water. Besides the matter of consolidating and improving treatment of collectible wastes, there are certain other diffuse and stubborn sources of pollution, as will be seen, for which good counter measures simply do not yet exist—among them are surface runoff during local storms and overflow from combined sewer systems.
If the collectible wastes were diverted out of the upper estuary and if it proved possible to cope quickly with other pollution or to ignore it, during prolonged use salt water penetration from downstream would take place as fresh water was withdrawn above and not replaced. Studies on a mathematical model of the estuary indicate that under conditions that could materialize, this would make the water at the intake too salty for use. A barrier dam across the entire estuary at one or another point in the freshwater section could prevent such penetration, but would be hugely expensive and undoubtedly more obtrusive on a much-used part of the riverscape than most upstream reservoirs could possibly be.
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.
In terms of metropolitan Washington's water supply, considered apart from other Basin water problems, the best reservoir site by far in the whole Potomac drainage would be the old River Bend site or the one proposed in 1963 at Seneca, both just upstream from the Falls above the metropolis. In one package, either of them would impound enough water to take care of any likely municipal and industrial demands of the metropolitan region for more than a half-century, besides trapping most silt from upstream to keep it out of the estuary, and providing a good measure of protection for flood-susceptible metropolitan shores. Furthermore, the proximity of such a reservoir to the city would ensure a great deal of aquatic recreation for people there and would somewhat simplify water management problems.
Thus, it is natural that Seneca, the latter proposal of the two, has found strong champions among metropolitan administrators, water engineers, and planners whose thinking has to be primarily in terms of sure and efficient water supply and flood protection. It has found equally strong opponents, however, enough of them to have stalled it to date. It is not yet dead, for it emerges in each new discussion of the city's water situation. It will not be dead until the metropolitan water problem, short-term and long-term both, has found a full satisfactory solution in other terms.
Our feeling remains unchanged since the publication of our Interim Report: that when all factors are weighed and future uncertainties are taken into account, Seneca should not be built at this time. If the price in money would not be high in relation to immediate "market" advantages gained, the permanent price, in river and countryside and those other intangibles that are getting to have more and more weight in men's minds year by year, would be heavy.
The full main stem Potomac, carrying the water from the combined North and South Branches and the Shenandoah and the other upper tributaries down through the Blue Ridge water gap and across the rolling Piedmont and the Fall Line, is at its most typical in the 39 miles from Harpers Ferry to Great Falls. Seneca as originally proposed would inundate 35 miles of this stretch, together with islands and bottomlands, forests of big hardwoods, meadows and productive fields, and that much-used segment of the publicly owned C. & O. Canal, with the trail along its wooded towpath. Even reduced in size and designed as strictly a water supply structure, it would have many of the same effects. There is special and tranquil beauty in this piece of the river, which makes a fine float trip and is much fished, as well as a lot of historical significance dating back to the Senecas and the Piscataways and before. Here these things are not forgotten and removed from men's reach but are available to metropolitans who go to the trouble to seek them out, as many do. Nor is there anything else around to take their exact or even approximate place if they were gone.
It has been pointed out that if the metropolis grows according to predictions, a major part of that growth is going to be upriver, and the main stem of the Potomac will have the same relationship to the metropolis of the future that Rock Creek has to the Washington of today. Thus the decision that is made about the main stem in our generation is similar to the decision that planners had to make about Rock Creek three-quarters of a century or more ago. Those planners decided magnificently well, bequeathing to the future an urban stream and park unique in this country and perhaps the world, a treasure that the public is presently defending against other, newer, subtler threats than mere damming or encroachment.
A reservoir above Seneca clearly could not mean that sort of thing. It would be a useful lake, but devoid of the changeless tone of the Potomac as it flows there now. The reservoir's proper functioning would require fluctuations in its level, with occasional ugliness at the shoreline, and if it would permit a great deal of happy water-skiing and flat-water fishing, the same opportunities are going to be available to Washingtonians in the nearby estuary when it is suitably cleaned up, even though the section immediately adjacent to the metropolis may take a good while to bring up to swimming standards.
In terms of the overall good of the people of the metropolis and the Basin and the country, the water situation at Washington now and during the near future hardly bears a desperate enough aspect to warrant the sacrifice of much of the main flowing river to a reservoir which, like the freshwater estuary, could not be meshed with upstream needs but would serve only the urban areas at and below the Fall Line. Conceivably at some future time, if technology should renege on its promise to bring forth good new alternatives, and population pressures continue to grow, the city may badly need a reservoir there. It is a uniquely valuable site. For that reason, we repeat our Interim proposal that the reservoir site, minimally defined, be preserved against the mass encroachment with which it is imminently threatened, and be utilized principally as part of a major park complex protecting the river and its shores. To defer irreversible decisions and to leave them as much as possible to future generations whose conditions of life and desires we cannot predict with accuracy, can be a principal way of maintaining freedom of choice.
In the category of reservoirs, at the other end of the spectrum are the comparatively small headwater dams that the Soil Conservation Service has been designing and supervising for three decades in authorized watersheds throughout the country. These structures can serve several functions and can furnish for small watershed areas and small centers of population many of the benefits that the Corps of Engineers and Bureau of Reclamation dams furnish for large areas. On their own scale, they are vulnerable to some of the same objections that are aimed at large reservoirs. But the scale is smaller; they tend to be less imposing and pre-emptive of good land than big river dams, "catch the water where it falls" to hold it for local use and to alleviate local flooding, and are backed up by erosion control practices in a program that has proved to be one of the best available stimulants to good land use. For these reasons they have appeal for many rural people and conservationists.
However, the conclusion which some of their supporters have reached is that if only enough of the small dams could be built throughout the headwater areas of a river basin, they would eliminate the need for most other forms of water management, leveling out flood and drought flows and holding a great aggregate amount of water on tap for use anywhere down the line. At times in the past, the controversy between supporters of big dams and supporters of little dams achieved the proportions of a bloodless war, but after a good many years of testing and observation it is now generally agreed by hydrologists that both have their place and that the most appropriate focus for the small dams' functioning is local.
At any rate, they are not an answer for Washington's problems. Even if enough of them were installed specifically to provide the storage volume needed for metropolitan use, the question of operation—ensuring and coordinating releases from a large number of places at varying long distance upstream from the point of intended use, in such a way as to make the required volumes of water arrive at the right time, without waste—would be very difficult even with much more sophisticated and expensive design than these structures customarily have. Without it the problem would be insuperable.
Thus, for metropolitan Washington's water in the near reaches of the future, some reservoir storage is indicated with fewer ecological, recreational, and scenic drawbacks than a Potomac main stem dam, and more efficiency for massive supply than the small headwater structures. Since the Potomac river system is a unit, with the metropolis at the downstream end of its non-tidal part, water stored anywhere in the upper Basin can be released for use there. This gives much freedom of choice in the selection of sites for reservoirs and in the combination of releases from various places to make up an adequate total supply, though obviously good management will be needed to coordinate the releases and avoid the waste of water.
It also means, if good principles of river-basin management are followed, that reservoirs to supply water at Washington can be located and designed so as to satisfy major upstream demands at the same time, and that they can be fitted in with regional and Basin needs for water quality improvement, flat water recreation, and in some places flood protection. In such conjunctive planning, based in the Basin's physical unity, commencing now and continuing on into the future as new needs and new ways of satisfying them come to view, lies the main hope of developing the Potomac water resource in such a way as to avoid waste of money, waste of water itself, and waste of the landscape and the general environment. Without it, nothing can result but a piecemeal haggling to bits of the river system as local demands grow acute and local pressures force the adoption of one-shot measures. With it, towns and areas and industries can be guided toward sensible and thrifty action that fits in with the wellbeing of the whole Potomac region—toward buying a share in the water of a rightly designed, rightly placed reservoir large or small, toward development of ground water resources where these are adequate, toward the use of new technology that may be feasible and suitable.
The range of choices is certain to enlarge with time, and the ease with which right choices can be made. In this computer age, mathematical models of river systems, including the Potomac, are at work manipulating hydrological data and quickly indicating optimum coordinated solutions for given water problems that formerly would have taken many weeks to solve, if indeed men could have arrived at such exact solutions at all. Computers are no better than the material that is fed them, however, and the need for new water data—for facts—is acute, if computers and the men who run them and the policy makers to whom they report are to pick the best ways of doing things. So is the need for means of giving "intangible" values their right weight in the whole process. But the computers are the keystone of the new technology and they are going to make right coordination simpler.
With coordination also, as we shall see hereafter, there is the strongest possibility of getting the river system clean again and keeping it that way, and furthermore of vouchsafing some measure of protection to the landscape through which it flows. For the physical unity of a river basin has many implications, and not the least of them is that the people who live there can be guaranteed at least a physical chance to lead full and wholesome lives.
Water supply for upstream areas of the Basin, then, is not a separate thing from water supply for the downstream metropolis and should not be treated as separate. They are all drinking from the same fountain. Where an upstream demand is great enough or is going to be great enough in a short span of years to warrant major storage, that storage must be keyed in with all other demands that it might meet or help to meet, including that at Washington. Where an area of lesser need is shut off by its location from sharing in such major storage, groundwater development or headwater reservoirs may well be the answer, but these measures too should be made to serve as many purposes as may be required for the protection of the area's whole range of interests and the good of the entire Basin. The need for such interweaving—for coordination, for planning and action that are unified—is primary, and will emerge again and again.