The Nation's River Part 6

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Ships and large boats in the estuary, in accordance with an unfortunately persistent nautical tradition, generally discharge toilet wastes and garbage directly into the water on which they float. Some of these are coastal or transoceanic vessels, both commercial and naval.

Many more belong to the fleet of pleasure boats which have been increasing at Washington despite the water's unpleasant state to which they add their bit, degrading the element that is supposed to provide the enjoyment for which the boats were built. It is not a problem limited to the Potomac estuary, but widespread these days and the focus of much concern among public health and pollution control authorities, conservationists, and the boat and marina industries themselves.

Around the various marinas to be found along metropolitan sh.o.r.es--several of them Federally owned--sanitary facilities are generally skimpy, and no regulations govern the discharge of wastes from boats. Since individual marinas may berth as many as 600 or 700 craft, a great many of them in daily use during the recreation season and some inhabited as dwellings the year round, summer conditions that frequently prevail around these places are not to be described in polite terms.

Less visible at the point of origin though not in its ultimate effects is the huge organic load that comes to the estuary in the effluent of local sewage treatment plants, estimated at possibly 300 to 350 million gallons per day. There are many smaller plants strung out down both sh.o.r.es of the upper estuary, but four larger ones handle the bulk of metropolitan sewage. Of these, three--the main plant at Blue Plains in the District, the Alexandria plant, and the Fairfax County Westgate plant--furnish secondary treatment, and the fourth, the Arlington County plant on Four Mile Run, is on the verge of putting new secondary facilities into operation.

Yet the same problem of plant operation that exists in the upper Basin also rears its head here. A casual boat ride down the sh.o.r.eline with a few excursions up tributary creek-mouths demonstrates that many of the smaller plants, including a number of Federal ones, are emitting a very low quality of effluent, and this is borne out by sanitary surveys. The proliferation of such small plants around cities and elsewhere is a headache to sanitary authorities, for their very size and numbers create a probability of trouble. Much effort is going into eliminating them and channeling the wastes they receive into the larger plants.

But the large plants themselves at this point are a much bigger part of the problem; on the basis of sheer volume, their contribution to estuarial pollution dwarfs all others. The Blue Plains plant is by far the largest of the four, handling wastes from about 1.4 million people in Washington and outlying areas on both sides of the river. By the terms of a conference convened in 1957 by the Public Health Service to investigate the sanitary state of the Potomac at Washington, the District committed itself to maintain 80% efficiency of treatment at this plant, which was then brand new. Last year, ten years afterward, the most generous recent calculation of the efficiency there was 62%, and some qualified observers expressed a conviction that Blue Plains had never consistently functioned at much over 50%--in other words, it had been returning to the estuary una.s.similated organic materials equivalent to the raw discharges of a population of roughly 500,000 to 700,000 people each day. Nor do these figures include a great deal of sludge that has been flushed on into the river when digesters have failed to function properly, or the plant's frequently inadequate use of chlorination against bacterial pollution and odors. Since the same 1957 conference required of the other metropolitan jurisdictions only that they do equally as well as the main plant in quality of treatment, they have clearly not been obligated to superhuman effort.

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Criticism of Blue Plains is in part criticism of ourselves. Because of the distinctive relationship between the District and the Federal Government, the District's treatment plant is in a sense a Federal installation, funded through Congress and with more direct links to Federal water quality agencies than any other big munic.i.p.al plant in the country. The number of people the plant serves has, of course, increased greatly in the past ten years. It may have been, as has been claimed, somewhat underdesigned to begin with, and it undoubtedly needs expansion now. Yet a rather substantial improvement in the quality of treatment there in quite recent months, mainly under the stimulus of this planning effort and the present surge of interest in the Potomac, indicates that had emphasis on low operating costs been subjugated to pride in results, the present plant could long ago have been made to function reasonably well and the estuary would have had to cope with a much lighter load of wastes.

The truly spectacular manifestation of pollution in the metropolitan Potomac is the periodic growth of algae there in summertime. When conditions are right--when sun, summer temperatures, low inflows from the river above, and a heavy concentration of nitrate and phosphate nutrients all combine to make of the upper estuary one vast inspired pool of fertility--the whole surface of the river may be covered with a thick bright emerald mat, and boats that pa.s.s at speed leave wakes of green instead of white. The infestation may extend downstream for thirty or forty miles, in various degrees of concentration, and even if the water were bacterially safe this "bloom," as it is called, would prohibit its recreational use by anyone without a strong stomach. It further disrupts aquatic life balances, and periodically dies and decays aromatically, setting off whole new cycles of oxygen depletion, fish kills, stink, and fertilization.

The problem is one of fertility, of course, and stems from the huge quant.i.ties of nitrogen and phosphorus perennially present in the water.

Some of this comes down from the upper river--where, as we noted, much of it derives from land runoff--but by far the greatest part of it originates at the metropolis and enters the river through the effluent of waste treatment plants. Efficiency of operation has hardly anything to do with it, for even the best standard treatment has little effect on nutrients.

Eutrophication is the scientific name of this kind of overenrichment. It is occurring in many places, Lake Erie being the best-known single example in this country. Though its causes are mainly known, the process itself is still not fully understood, particularly in regard to the function of nitrogen and the way it works. But the other key element, phosphorus, has been more amenable to study and to possible action. It occurs in body wastes, in artificial fertilizers, as a by-product of natural decay, and very notably in detergents. Some eight tons of it are released into the estuary each day from the treatment plants in addition to the undetermined but much smaller amounts arriving from upriver, and the usual overall acc.u.mulation is enough to make the river's phosphorus content exceed that considered desirable all the way from Theodore Roosevelt Island to Quantico, Virginia, and below, which represents the general extent of the summertime "blooms."

Dilapidation begets disrespect, and the abused and often repellent waters of the upper estuary are undoubtedly subjected to much additional miscellaneous pollution by people who believe perhaps that a little more cannot possibly matter. Again, Federal or Federally connected inst.i.tutions have not been setting the best possible example, and there are many of them around the capital city. Unwarranted waste discharges of one kind or another have been traced to most of the military installations fronting the river, to military hospitals, to government heating plants, to the National Zoo, to National Parks, and to similar Federal sources including the marinas already mentioned. In most cases, measures are now being taken to eliminate these discharges, but it is a commentary on the complexity and difficulty of the whole task of dealing with pollution that at the level of government where real concern with the problem has been acute for a decade or more, and furthermore at and around the very seat of that government, such practices should have persisted this long.

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Junk and debris of all descriptions infest the metropolitan river, floating about, washing onto the sh.o.r.es, poking up stolidly here and there out of mudflats. Most items in a dreary inventory that might be compiled would turn out to be something that was discarded somewhere it didn't belong by someone who did not want to go to the trouble to put it where it did belong. Therefore, the main source is undoubtedly simple disregard for the sensibilities and rights of others, multiplied and complicated by the immense number of people in the metropolis and the wide territory they occupy. In our study of Rock Creek last year, some powerful subsidiary reasons for the prevalence of debris turned up also, ranging to streetcleaning methods and the inconvenient hours kept by some public dumps where citizens have to carry their larger trash.

Metropolitan problems are seldom simple, and many of them in one way or another manage to inflict a part of their complexity on the river at the national capital, which is sad but possibly appropriate in a time like the present.

The lower estuary

Downriver from the main effects of the metropolitan complexities, the widening brackish and salt portions of the Potomac estuary form a generally healthy body of water, though changes loom as the metropolis moves inexorably outward from its center and as. .h.i.therto remote Tidewater areas are brought more and more under the influence of modern ways of being. Localized problems of pollution point to general dangers that will certainly materialize unless safeguards are set up in time, for estuaries are delicate, immensely productive, and still somewhat mysterious aquatic environments that have been and still are too much taken for granted.

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Rapid human intrusion on estuaries during the past twenty years has been making apparent their phenomenal value in a natural condition.

Vulnerable, attractive to diverse interests that work their beds for sand and gravel and fill in their marshes for development and casually pollute them, they have recently been called America's most endangered natural habitat. They are almost unbelievably fertile places, with involved biological cycles that can convert the fertility into usable food at rates per acre far exceeding those of the finest farm land; in terms of money, one recent set of experiments indicates the possibility of attaining an annual sh.e.l.lfish production on tended beds worth over $26,000 an acre.

Furthermore, aside from the direct harvest of this wealth from estuaries each year by commercial and sport fishermen, these in-between waters make an indispensable contribution to the entire Atlantic coastal fishery, an industry worth a billion dollars a year. The reason for this is that at least 70 percent of coastal fishes spend some essential part of their life cycle within an estuary--sp.a.w.ning there, or pa.s.sing through on their way to sp.a.w.n in running fresh streams, or moving in as fry from the rivers or the open sea to find a "nursery" in one of the varied estuarine habitats--bays, marshes, sandy sh.o.r.elines, mudflats, tidal creeks, or weed beds.

The oysters from the famous beds in the Saint Mary's River off of the lower Potomac are mainly condemned as unfit for consumption because of local sewage pollution, and these beds are not the only unfit ones, for towns and resorts in the region have been growing and sanitary facilities have not been keeping pace. Already some arms of the superb natural harbors formed by the tributary creeks are noxious with discharges from boats at big marinas, and gravel dredging is stirring up silt to smother bottom life, including sh.e.l.lfish. As Tidewater agriculture revives and modernizes, pesticides and artificial fertilizers are coming to be as much a part of the scene there as in other farming regions, and may be expected to influence the estuary--in fact, they undoubtedly already are doing so in subtle ways with effects not yet apparent.

Yet most of this part of the river is still beautiful and continues to yield good harvests of seafood. The Potomac River Fisheries Commission has been alert to obvious dangers and has moved against them where its powers have permitted, and natives of the area are increasingly alert in protecting the estuary. Many of them depend on it for a living, most are oriented toward it for their pleasures, and until lately a good many of them counted on it for transportation. In a number of different ways, it matters in their lives. And that fact offers some hope for the future, especially if it is fostered and strengthened by overall protective measures.

Techniques for cleaning up

Two main general approaches to water quality improvement exist: treatment of pollution at its source or occasionally after it has entered a stream, and augmentation of the stream's flow to help it a.s.similate loads of waste beyond its natural capacity. A third possibility in certain situations is the diversion of wastes out of a stream's drainage entirely. In practice, these methods can be varied and combined in any number of ways to fit a need.

To take the last one first, diversion of whole wastes as received from their sources is a total and dramatic means of coping with a pollution problem stemming from collectable wastes, but it often has disadvantages. One of these, of course, is the possibility that the pollution problem may be simply transplanted elsewhere--that the water in which the wastes eventually end up will suffer. Another is loss of water from the stream system. If, as is usual, a town gets its water out of the local river or a tributary and does not give it back after use--preferably well cleaned up--other users downstream are not going to have as much water available to them, and the essential processes and ecology of the river itself may suffer.

The only place such wholesale diversion of wastes has been seriously considered in the Potomac Basin is at metropolitan Washington, whose sewage could feasibly be piped across Chesapeake Bay and the Delmarva peninsula and well out into the Atlantic--possibly, as has been suggested, in combination with sewage from Baltimore. It would be a permanent means of disposal, but very expensive in terms of both investment and operating costs. Furthermore, though in the estuary no downstream users would suffer a loss of water supply, the water content in metropolitan sewage has at times risen as high as 80 percent of the flow of the river above the upstream intakes. The effects of such a subtraction of fresh water on the estuary itself--changes in flow, and in the penetration of salt water upriver, with an inevitable alteration in valuable fisheries and the whole balance of aquatic life established through millennia--could easily turn out to be disastrous.

Standard treatment of pollution at its source consists of the primary and secondary processes we have glanced at, sometimes adjusted to specific industrial wastes. It has to be brought up to peak efficiency along the Potomac, for this is a "known factor" of great significance.

Plants can and must be improved physically where necessary, and qualified operators provided for them. Collection systems have to be improved or enlarged in many places. Diminutive plants, doomed to inefficiency by their size and the financial impossibility of hiring expert workers for them, need to be eliminated in favor of regional waste collection and treatment facilities, which are quite feasible, particularly in the watershed units of the upper Basin.

Even so, it has emerged clearly to view in this Potomac study that standard treatment alone is no longer an answer in areas of concentrated or continuous population and industry, where the leftover wastes and the nutrients in the effluent from even well-run standard plants can often add up to a killing load for water.

Total diversion of treatment plant effluents is sometimes possible, but is subject to the same objections that apply to total diversion of untreated sewage--possible pollution of the receiving water (such as Chesapeake Bay or the lower Potomac estuary, both of which have been suggested and considered for Washington's effluent) and the alteration of hydrological and ecological conditions. Modified forms of effluent diversion, however, may offer more promise.

Effluents from maximum standard treatment processes, for instance, can be injected into underground strata as recharge water for aquifers--a process mentioned earlier as one alternative in the emerging package of water supply techniques--or may be spread over the surface of large areas of rural land where they serve as irrigation water and fertilizer combined, as well as soaking down into underlying aquifers. For large scale, sustained use, both of these practices still offer some technical difficulties--algae buildups that interfere with percolation, odor problems, limited aquifer capacities, the large amounts of land required for spreading, the effect of rain and freezing weather, and such things.

And where the aquifers in question do not feed the original source stream system, a big subtraction is again involved. But for certain conditions in certain places these problems are undoubtedly going to be worked out.

A more modest but highly useful modification of effluent diversion is the s.p.a.cing of treatment plant outfalls at intervals for a long distance downstream from a treatment plant. If nutrient and organic loads are not tremendously heavy in relation to the size of the receiving stream, this procedure can help to a.s.sure that no one stretch gets too strong a dose of them. It is likely to find good use in the Potomac and elsewhere, though only as an adjunct to the best available treatment.

"Advanced treatment" and "tertiary treatment" are becoming common terms nowadays. They refer to any of a considerable array of additional or intensified processes aimed at attaining levels of purification that would have cost an impossible price a few years ago. Most of them are still experimental and often still expensive, and they involve everything from filtration through powdered coal to flash distillation, with still others in prospect. Some bypa.s.s conventional treatment and deal with whole raw wastes. More build on conventional treatment and are designed to remove nutrients and residual organic material from its effluents. Of these latter approaches, at least one, involving lime precipitation and other processes to remove nearly all phosphorus and most remaining organic material, is nearing a stage of development and economy that may warrant important use. It will be applied first at the new Piscataway treatment plant of the Washington Suburban Sanitary Commission in Prince Georges County, Maryland, which will also incorporate research and demonstration projects in nitrogen stripping and other things.

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In the long run such advances offer the main hope of clean water for a superpopulated future America, where volumes of wastes are going to be enormous and first-rate off-stream treatment is going to have to be the main way of handling them. Even where wastes can be collected easily for treatment, however, as in industry or in sewered populated areas, it may take a good many years to work out varied forms of advanced treatment adaptable to different sets of circ.u.mstances, at prices that communities can afford to pay--and a willingness to pay what can be paid is going to have to be a part of the long clean-up job ahead. Undoubtedly continuing research will work out such forms of treatment, but the research itself may be quite costly and no one can predict its pace.

Where waste sources are too diffuse to be channeled into collection systems--as along many agricultural streams heavily polluted through land runoff and drainage, and also in some urban situation--present tools are extremely limited. Soil conservation practices aimed at cutting down erosion--to be discussed within a few pages--tend to keep not only silt but nutrients and other substances on the land to some extent. Concentrated sources of animal manure such as dairies, poultry operations, and feed lots can be brought under some control by fencing stock off from streams and by techniques of lagooning and later field spreading, which need much wider use in the Potomac Basin. But even if these approaches were applied fully throughout the region within a shorter time than appears likely or even possible, land runoff would still be a heavy source of water degradation.

Hence it is probable that flow augmentation--sometimes called "flow dilution" or included in the broader term "flow regulation"--through the release of stored water, will be an important auxiliary tool in water quality management for a good while to come. This is not a form of flushing wastes downstream from their source and out of sight, as some opponents continue to insist, but a means of helping streams to oxygenate and decompose excess wastes by the same processes they have always used on natural and normal loads. On the other hand, neither is flow augmentation the end-all cure for pollution that enthusiasts of a few years ago claimed it to be. Its effect on slow ma.s.ses of water is uncertain and probably minimal, and too much dependence on it even for flowing streams would obviously encourage neglect of the practical and moral need to keep filth and troublesome substances from getting into the streams in the first place. Furthermore, such dependence would lead rapidly to a point of diminishing returns, like the flood-plain development and protection cycle examined in the preceding chapter.

Increases in populations and pollution would lead to a necessity to provide more and more augmentation of flows, with storage s.p.a.ce in reservoirs becoming more and more expensive precisely as flood protection does. Flow augmentation is no subst.i.tute for good treatment, but a valuable adjunct.

In the record drought summer of 1966 the South Fork of the Shenandoah, heavily polluted with munic.i.p.al and industrial wastes near Waynesboro, and with fertilizer, manure, and other substances in drainage from the rich and intensively utilized farm country through which it flows, ran very low for months. In many places it was slimy and unpleasant, and aquatic life suffered to some extent, but the picture was not nearly so dismal as it would have been if the river had not been helped out more or less by accident. The source of this help was some 2000 gallons of water per minute that the Merck plant at Elkton and the Dupont plant near Waynesboro were releasing after having pumped it out of deep aquifers and used it for cooling. If all sources of pollution had been receiving adequate treatment, this minimal dilution might not have been so badly needed to avoid the fish kills and algal stagnation and other results that would have ensured without it. But "all sources" include the problematic agricultural drainage, and for that matter the definition of "adequate treatment" is going to have to go up and up in our expansive future.

The sad situation of the smaller and much less industrialized Monocacy in the same summer underscores the point. The Monocacy flows through similar farming country and pa.s.ses by a few towns. The largest of these is Frederick, Maryland, for whose approximately 40,000 people the little river furnishes water and a conduit to carry away the effluent from their average-to-good secondary plant. At times during that dry summer practically the entire flow of the river below Frederick consisted of effluent, with effects on stream life, esthetics, and the general surroundings that are not hard to imagine.

Another good example of a place where, under present conditions, augmentation could sometimes be used beneficially is at Great Falls and in the Potomac gorge below. Heavy public expenditure has protected the sh.o.r.e in much of this neighborhood and provided pleasant recreation areas whose main scenic focus is the violent magnificence of the river in its plunge. But the magnificence becomes a rather drab joke in dry summers when metropolitan withdrawals of water above that point shrink the river to a semblance of normal flow.

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The North Branch and some smaller Basin streams also need this same kind of help and most will continue to need it even when the best economically feasible treatment of all collectable wastes entering them is ensured. It can be provided out of reservoirs, large or small, whose need for other purposes as well will keep the cost of dilution within reason. A future possibility, if research presently going on in the Basin verifies it and shows ways of putting it to use, is to employ ground water in the same way. There can be no doubt that if the flowing waters of the Basin are to be put back in good condition and kept that way under population pressures that are in prospect, flow augmentation in some places is going to be an important tool.

In the upper estuary, however, its usefulness appears to be far more limited. The plan proposed in the _Army Report_ of 1963, in line with a Public Health Service approach emphasized in the 1961 Water Pollution Control Act, was designed to provide an eventual minimum flow into the upper estuary of 3100 cubic feet per second, or around two billion gallons per day, for the purpose of dealing with treatment-plant effluents and miscellaneous pollution. But more recent investigations have raised strong doubt as to whether such augmentation could do the job in the estuary with its huge volume of water, and its slow, tide-baffled currents that greatly lessen its a.s.similative capacity.

In terms of dissolved oxygen, dilution of such a body of water for quality improvement appears to decrease in unit effectiveness as the volume of dilution is stepped up, which means that past a certain minimal point of improvement it gets expensive and requires unreasonable amounts of storage. In terms of nutrients, one authority has calculated that about 20,000 cubic feet per second would be required to reduce the nutrient level in the upper estuary to a point where it would be only twice that of a normal and healthily "rich" section of the upper Chesapeake Bay. Some augmentation below the point of diminishing returns will undoubtedly be needed, not only for the estuary but to keep the river alive in its gorge above Washington during periods of low flow. But as a main tool for the metropolitan river, it will not subst.i.tute for achievement of the best possible standard treatment followed by advanced treatment and other techniques.