CHLORINE: Destroys organic materials
PHOSPHATE: Lessens pipe corrosion
FLUORIDE: Lessens tooth decay
CARBON: Controls taste and odor
ALUM: Forms "floc" (snowflakes) to trap impurities
LIME: Helps "floc" formation; lessens pipe corrosion
]
The basic and usual damage comes from oxygen depletion. A stream has a
natural capacity for hastening the decay of organic wastes, which is
determined by such things as the volume of its flow, the pollution
already in it, its velocity and depth, and its temperature. When that
capacity is exceeded, as we have noted, too much of the stream's oxygen
is used up by the process of decay and the stream, which is an
intricately complex work of living things, begins to die. Under really
bad conditions, the waste solids themselves cannot all be assimilated,
and hence may build up in layers of stinking sludge at the bottom of
the stream and continue to seize available oxygen for a long time
thereafter.
Conventional waste treatment, in plants built by towns or by industries
whose raw materials are animal or vegetable in origin, is aimed at
removing the solids in the wastes and reducing the bio-chemical oxygen
demand--called B.O.D. It is a speeded-up version of the same process of
purification that goes on normally in any stream when loads are not too
heavy. "Primary" treatment removes such solids as will readily settle
out and passes the rest on back to the stream as part of the effluent.
"Secondary" treatment plants, after settling out the gross solids, speed
up decay by furnishing air to the bacteria that eat up dissolved and
finely suspended materials; a good secondary plant, under much more
skillful supervision than is usual, can get rid of 85 or 90 percent of
the organic materials and the associated B.O.D. by the time it turns its
effluent into a stream. How damaging that effluent will be depends on a
number of things, chief among them being the size and condition of the
receiving stream and the volume of organic materials that went into the
treatment plant in the first place. A riverside town of 1000 with a
secondary treatment plant operating at 75 percent efficiency is going to
inflict on its river a daily load roughly equivalent to the raw sewage
from 250 people.
Over the years a lot of hard effort, notably on the part of the
Interstate Commission on the Potomac River Basin, has resulted in some
degree of treatment for about 85 percent of all municipal wastes and 83
percent of those produced by industry along the Basin's flowing
streams. Put in another way, by INCOPOT calculations the total waste
load imposed on the Potomac is only about three-quarters of what it was
in 1956, despite a population increase of nearly a fifth.
That it is still much too high in many parts of the upper Basin does not
require elaborate instruments to detect, but only a nose and a pair of
eyes. A very few industries and towns are still dumping raw wastes, and
many of the others need better and bigger sewers and treatment plants or
better operation of the plants they have. Sewage collection systems are
sometimes of the old-fashioned combined type, like Cumberland's--and, as
we shall see, like Washington's--which have to carry storm runoff as
well as wastes, and overflow during rainy periods, releasing heavy
pollution without treatment. But even separate sanitary sewers are often
overloaded by having to serve greater populations than they were
designed for, which means that their escape valves may leak raw sewage
more or less continuously into surface watercourses and that the quality
of treatment given the sewage that does reach the treatment plant
signifies less than it ought to.
Antiquated or overloaded treatment plants cause much trouble. Old
primary plants too small for present populations often remove only about
a third or less of the organic material, but by their very existence
they tend to lull communities into a false conviction that they are
doing their part toward clean rivers. Tiny plants of the sort authorized
locally for new leapfrog subdivisions and vacation colonies are usually
doomed to restricted efficiency by their very size. These often are
underdesigned even for initial loads, let alone for the growth that
comes later, and most of them are poorly run.
This question of operation is crucial. A new, well-designed, expensive
plant in slovenly or inexpert hands--a frequent paradox--can put out a
much greater waste load than a well-operated old one. The plant at
Romney, West Virginia, on the lower South Branch, the best example of
responsible operation in the Basin, is old, but because it is well run
it usually achieves about 92 percent elimination of B.O.D. in comparison
with the 75 percent or even less that some newer and more imposing
plants can claim.
The reasons for poor operation are various. One is a shortage of
qualified operators, based on a need for better salaries, more training
programs, and rigid mandatory State certification of operators'
abilities. Another reason can be a pinchpenny attitude on the part of
municipal authorities toward sewage treatment. It is one sizable
expenditure whose results cannot easily be pointed out with pride to
local taxpayers at election time, for its main effect is usually
downstream from the municipality itself. Thus the big encompassing
reason for bad plant operation--cutting corners, refusing to spend what
needs to be spent, failing to supervise--has to be called philosophical.
It comes from a failure on the part of local operators and authorities
and much of the public to comprehend the immorality of deliberate
avoidable pollution, and it may mean that municipal operation of
treatment plants is itself often a major source of trouble.
A clear example of this philosophical deficiency is one large Basin
treatment plant that was reported to have "handled"--i.e., properly
disposed of--a third less sewage sludge in 1965 than it had in 1960,
despite a large increase in the population it serves. The unhandled
sludge, of course, went straight into the local river for reasons of
convenience, economy, and callous indifference.
For the most part, large private industry demonstrates more
responsibility in this respect than the Basin's municipalities or
Federal installations. There are some miserable exceptions where
individual industries dominate a locality's economy and take casual
advantage of that fact. But responsible industry is concerned with
public relations, and knows that a fish kill or a gray-blue stretch of
blighted water downstream from its outfalls is the poorest kind of
public relations to be had.
To be able to say precisely how much bad plant operation is adding to
pollution in the Potomac will require exhaustive and continuous sampling
and analysis of a kind that may be expected now that the Water Quality
Act of 1965 is about to make itself felt through application of new
State water quality standards. But experienced observers in INCOPOT and
elsewhere feel strongly that bad operation does much more damage than do
over-aged or outgrown facilities, though these play a big part too.
Bacterial pollution--the category of most interest from a public health
standpoint--fluctuates a great deal in the Basin's flowing streams, but
is heavy in most of them by current standards during times of normal
flow. It may come from raw waste discharges, from treatment plants that
skimp on chlorination of their effluent, or from storm runoff and
natural drainage off the land and urban pavements. But before anyone can
confidently say how dangerous it is to swimmers and others who make
intimate use of rivers and creeks, water scientists are going to have to
learn more about its measurement and classification than they presently
know.
[Illustration]
No easily applied method of testing can effectively establish the
guaranteed absence of human disease germs. The traditional "Coliform
Count" plays safe, as it must. It measures the concentration of certain
easily spotted "indicator" organisms that do not themselves make people
sick but are always voluminously present in the fecal discharges that
can carry harmful germs, and it gauges the danger by the concentration
of these indicators.
However, concentrations of coliform bacteria, originating in animal
manure or elsewhere, may invade a stream through runoff from rural lands
without having any meaningful relationship to human disease germs.
Counting them under such circumstances is a little like measuring the
depth of the proverbial well by the length of the pump handle.
Furthermore, no one really knows how easy or how hard it may be to catch
given diseases by swimming. In this country, outbreaks of leptospirosis,
an illness common to man and certain animals, have been traced to
swimming holes, and other links are obvious. On the other hand, some
careful British investigations turned up a good many quite healthy
people who habitually splashed about in sea water teeming with
pathogenic organisms of one sort or another. Sea water and fresh water
have vastly different qualities, but the subject is presently full of
confusion, and it needs much research.
Land runoff in general furnishes a large amount of pollution of all
classes, and in all parts of the upper Basin except the least-used
forest sections. Besides bacteria, heavy loads of organic material may
be washed into streams in regions with high densities of livestock or
poultry, and some pollution of this sort is found practically
everywhere. The wild and domestic animal population of the Basin above
Washington has been estimated to produce wastes equivalent to those of
about 3.5 million people. Much of this is dealt with by the "living
filter" of the soil, but much also reaches the streams, associated with
sediment from erosion producing rains. And the sources, particularly in
areas such as those along the Shenandoah and the Monocacy and other
streams with wide rich valleys, are numerous and diffuse.
Nitrogen and phosphorus nutrients, which foster weeds and slime in quiet
stream stretches and contribute to the problems of the estuary
downstream, are found in undesirable concentrations in most of the
Basin's waters above the Fall Line. Not only are the growths encouraged
by these fertilizing agents ugly, but they also upset the ecological
balance of streams by favoring certain types of aquatic life over
others, and they can cause tastes, odors, and clogging in water supply
systems and sometimes, by rotting, a secondary sort of oxygen
deficiency. Nitrogen and phosphorus occur in the effluent from waste
treatment plants, for they are present in human wastes and in
detergents, and in dissolved form are little affected by standard
treatment processes. And in the upper Basin a large part of the nutrient
load in streams appears to be associated with sediment from the same
diffused land runoff mentioned above, for they occur abundantly in
manure, in synthetic fertilizers, in certain natural soils, and in
decaying organic substances of many kinds. The health and growth of
living things is dependent on these elements, of course; it is their
excessive release into waters that causes trouble.
From the same farming regions and even more from lawns and gardens and
parks in more populated areas, pesticides and other economic poisons
accompany sediment into the stream system or are blown into it as
sprays and dusts. They seem not to be as great a problem in the Potomac
as in some other rivers, but they are present in probably significant
amounts; indicator tests hover near Public Health Service drinking-water
limits in the river. Their use, here as elsewhere, increases year by
year, for they are tremendously effective against many of man's ancient
enemies. Being easily available, they are often used in uninformed and
careless ways despite government efforts to determine and publicize safe
levels of application. Knowledge about their side effects, both
immediate and long-term, is still full of gaps. Badly misused, they are
obviously dangerous. But information about the precise results of their
ordinary use and their buildup in nature accumulates very slowly.
The persistent chlorinated hydrocarbons--DDT and its relatives--last for
a long time after being released into the environment, concentrating at
various points in the natural food chain and often in man himself. It is
said that an average adult Californian's tissues today contain more DDT
than is allowed in beef for interstate shipment. But no one is yet
certain what this means in relation to that average Californian's
physical wellbeing, and in terms of fish and wildlife, though the link
between these materials and certain destructive changes can be seen,
evidence in other cases--the declining fertility and numbers of bald
eagles, for instance, which some investigators believe to derive from
pesticide residues--only points toward such a link. Until all the facts
are in and the impact of such poisons has been clearly restricted to the
pest species at which they are aimed, they are going to continue to be
a heavy concern for conservationists and others alarmed about
environmental pollution, along the Potomac and elsewhere.
[Illustration]
[Illustration]
One of the principal Potomac pollutants, silt, not only comes from the
land but is the land, most often good topsoil, washing away toward the
sea. Even under pristine conditions streams are likely to run somewhat
muddy after storms; it is a natural phenomenon, a by-effect of the way
climate carves landscapes. On the evidence, however, the Potomac
landscape since its colonization by white men has been undergoing a much
more rapid carving than anyone could consider to be natural. Most of its
streams, particularly in their lower reaches, are thickly opaque for
long periods after rain, and gross erosion in the Basin--the amount of
soil washed away from where it usefully belongs to somewhere
else--averages about 50 million tons per year, a major depletion of the
soil resource and a degrading influence on the landscape through
erosion. The part of this silt that gets into streams cuts down on the
usefulness of the water, creates ugly turbidity, chokes quiet pools and
reservoirs, suffocates bottom-dwelling creatures and plants on which the
streams' wholeness may depend, and rides down the current to add heavily
to the problems of the estuary, into which some 2.5 million tons of it
are annually discharged.
Sediment is dislodged from the land by the pounding action of raindrops
and the flow of runoff, and sometimes is washed from streambanks during
high flows--which may themselves be higher and more frequent because of
silt-clogged channels. The bulk of it can be blamed on unsound land use.
This may be rural, based in the old use-her-up-and-move-along pioneer
outlook that has never died out among us despite wide understanding of
better ways of doing things. People in places still overgraze pastures
and clean-cut timber so that rain can get at the soil and eat it away,
and they still farm land too steep to stay in place without its
vegetative cover, or they plow even suitable rolling land in straight
rows up and down hill so that water and soil sluice away together down
the furrows when it rains. Despite a sharply effective three decades of
work and public education by the Soil Conservation Service and other
agencies, these old practices continue in some places and cause much
erosion.
[Illustration]
Also, increasingly, bad land use involves the ways in which great
machines adapt the landscape to hundreds of sophisticated purposes. The
massive eatings of powered blades and scoops to get at coal and other
minerals on the steep slopes of the North Branch watershed and
elsewhere, add heavily to sedimentation. So do broad rights-of-way
gashed out of the countryside and left bare under storms in the months
before highway construction is done, and secondary roads that even when
finished may be left for years or forever with denuded clay shoulders
and ditches and banks that wash with every rain. And so, most
particularly, do the great polygons of rolling land around the Basin's
town and cities that are stripped naked by bulldozers and left sitting
in that condition for long periods, while they await the erection of
buildings and blocks of homes. This is occurring throughout the Basin,
but most notably around Washington, where the highest erosion rates of
all are found. We will take a look at its details and the reasons for it
a little further along in this chapter when we examine the estuary's
situation.
Except for the acid parts of the North Branch, the upper Basin's waters
in most places, most of the time, can still serve the "practical"
purposes to which they are put--irrigation, industrial uses, municipal
supply after purification, and even the absorption and digestion of
effluents from adequate, well-run treatment plants. Most of the streams
are usually good to look at, especially in conjunction with the superb
rural landscapes against backgrounds of wooded mountains that are
characteristic. They furnish much pleasure to fishermen, hunters,
boatmen, swimmers, picnickers, and other folk, though in some places it
is an open question, as we have seen, whether or not contact with the
water is prudent. And almost everywhere, aging locals can recall a time
when their stream was a happier amenity than now--when it held more
fish, ran clearer over stones and gravel not coated with weeds and
green slime, did not have the smell it presently emanates, was colder
and more copious....
Their nostalgia probably does not play them false, even though
conditions in many places are better now than in the intermediate past,
after modern times had settled in, but before INCOPOT and the Soil
Conservation Service and such influences had begun to push for reform of
the casual, anciently human ways of doing things in which present human
populations can no longer afford to indulge themselves. Some of the
gains that have been made are being cancelled out by growth and new
types of pollution, however, and in general the flowing Potomac river
system is teetering at the brink of bad trouble. It needs help.
If the flowing upper Potomac had any lingering oxygen deficiency in its
lower stretches--though it seems usually not to--it would tend to
rectify the lack in its turbulent eighteen-miles descent across the Fall
Line, a superb natural "treatment plant." Normally it arrives at
Washington charged with oxygen, but does bring down with it the part of
its nutrient load that has not fertilized upstream weeds and algae,
periodic waves of bacterial concentration, and a great deal of debris
and silt in season.
In the broadening, slowing upper estuary, its sluggish currents confused
by the twice-daily surge and ebb of tides, these materials from above
are stirred in with an array of specifically metropolitan
pollutants--with more silt off of the outraged urban watershed, with
junk and debris of a thousand sorts, with decaying substances and
bacteria from many sources, and with vast new quantities of nitrogen and
phosphorus. The consequence is a weighty and sometimes spectacular
pollution problem directly adjacent to the proud national capital. It is
at its vivid and aromatic worst in summer, when the most Americans come
there fondly to view the city and the Potomac, and when locals who want
to boat and fish and swim and do the other things one does on water
would make most use of the river--indeed, do make use of it in spite of
everything.
Like the meek, the upper estuary inherits the earth, or at least that
part of the Basin's earth that is washed downriver as silt. There are
enough fine suspended sediment particles in the water of the
metropolitan river to make it drably opaque most of the time, even
during relatively dry spells, when heavy sand and gravel dredging helps
to keep it stirred up. As the current loses force and washes back and
forth with the tides, the particles settle out slowly into smothering,
continually renewed blankets on the bottom, and over two centuries have
accreted into great mudbanks and shoals. Channel dredging to maintain
navigation has been going on since the early 19th century, about 180,000
cubic yards being presently removed each year. The dumping of the
dredged materials on the marshes and long low shores has built up wide,
flat, new flood plain areas around the city over the years, including
the sites of Washington National Airport, Anacostia and Bolling Air
Fields, and East and West Potomac Parks.
Such channel dredging has little effect on the gradual shoaling of this
whole part of the river in general. Miles of formerly navigable water
downstream from Memorial Bridge are now only one to four feet deep and
useless for either pleasure or commercial craft. It has been estimated
that present rates of deposition will within fifty years fill in the
upper estuary completely to a mile or so below Alexandria, except for a
river channel. The same process is at work in the tributary creek-bays
that give onto the estuary, some of which have silted so heavily since
Colonial Days that formerly thriving ports--among them Bladensburg,
Dumfries, and Port Tobacco--are now distant from the water.
The bulk of estuarial silt comes down the main river from the upper
Basin. But a heavy increment is added in the metropolitan area. Modern
mechanized development of the city's hilly environs on a huge scale,
continuing year by year with few thoughtful rules to guide it
heretofore, has brought about erosion that on individual patches of
bared land may reach a temporary rate of 50,000 tons per square mile per
year, and even average rates in this area are far in excess of anything
else in the Basin.
We had to examine the reasons for this rather closely last year in a
study of Rock Creek's ailments, whose findings we published in a report
called _The Creek and the City_. This much-admired metropolitan stream
has been relatively well protected, with the parks along its wooded
valley and an upper watershed that until quite recently remained
essentially rural. But as development has proceeded in standard and
careless ways--the wholesale stripping and scarification of big tracts
of rolling, fine-textured land, the long naked wait for development--the
creek has come to be muddy and ugly almost all the time and has been
spewing an estimated 100,000 tons of sediment a year into the estuary,
with frequent floods.
[Illustration]
[Illustration]
To help save the creek and its parks and to stimulate a better kind of
development of the rest of its basin, citizens formed a watershed
association under Soil Conservation Service auspices and brought about
the construction of two small upstream reservoirs to control
flooding--with results noted in the preceding chapter--and to collect
silt. They sought to promote better land use as well, for the
reservoirs' effectiveness is obviously dependent on their not filling up
quickly with an excess of sediment. Better land use around a city
depends on zoning and other legal devices to regulate the density and
distribution of construction, and on controls over the way land is
shaped, and a sharp conflict developed between the watershed's defenders
and the Council of Montgomery County, Maryland, in office at that time,
whose rezonings in favor of standard massive suburbanization and whose
failure to enact sediment-control ordinances threatened the whole
effort. Rock Creek has many friends, and their subsequent fight for its
salvation has had good effect, though much remains to be done.
[Illustration]
However, Rock Creek is only one of many metropolitan streams that need
protection, both for their own sake and for that of the estuary. Some
are getting it--in the preceding chapter we noted the happy example of
Pohick Creek in Virginia, where whole watershed planning is being
accomplished almost from scratch, before development. But many more are
being ruined by the steady advance of standard urban sprawl.
Thus the main cause of urban silt is faulty or nonexistent or powerless
land planning, and the problem merges with the whole question of
landscape preservation. The ecological principles involved in good
practical land planning--the distribution of uses based on what land and
water can take without being degraded and causing silt, flooding, and
downstream pollution--are the same basic principles that lead to scenic
beauty and a decent human environment. This is a subject we will explore
in more detail when we arrive at considering the landscape as a whole,
but for now it may be worthwhile to note that insofar as urban erosion
and silt stem from decisions of political agencies inclined to subjugate
well-known good land use principles to speculative pressures,
expediency, and other things, their origin is political and economic.
Organic materials are pervasive enough in the upper estuary that during
periods of even normal flow their decay pulls oxygen levels down. Under
usual conditions this B.O.D. grows worse and worse downstream and
reaches a peak in the neighborhood of Mount Vernon, though its effects
continue to be felt below. Fish kills among the rugged resident species
that predominate in these reaches of the river are not uncommon, the
shoreline windrows of deceased carp and perch periodically adding their
essence to what metropolitans have come to accept as the Potomac's
normal summer smell. And along with the organic materials are heavy
concentrations of bacteria.
The organic and bacterial load enters the estuary from many sources,
most of them local, for only a little of this material comes down from
the upper river. A significant amount of it issues from the network of
small urban watercourses like Rock Creek. Many of these were covered
over as storm sewers or troughed in concrete long ago, but they continue
to serve their age-old function of draining the lands they traverse,
even if through cast-iron gratings.
A good bit of the organic load in these tributaries consists of raw
human waste, incongruous and particularly obnoxious around a modern
city. The bulk of it is released in periodic surges when local
rainstorms overload the old-fashioned combined sewer systems of the
District of Columbia and Alexandria. In dry weather these systems send
both collected sanitary wastes and street drainage down to the cities'
respective treatment plants, but during storms when street drainage is
heavy the sewers' capacity is exceeded and overflow gates gush mixed
stormwater and sewage out into the streams, which carry it to the
estuary.
In the suburbs, more modern separate storm and sanitary sewers are the
rule, but they too have some problems of a kind we noted in relation to
the upper river. Investigations on Rock Creek revealed steady dribbles
of raw sewage entering the creek or its tributaries from a large number
of storm-sewer outfalls and other places. Partly these flow from
malfunctioning individual septic systems in outlying areas,
surreptitious connections of house sanitary sewers to the storm system,
breaks and leaks in sanitary sewers, and such things. Partly too they
seem to come from the fact that some sanitary sewers are having to carry
more sewage than they were designed to handle, so that their overflow
valves leak more or less constantly into the storm sewer system. The
capacity of sewage collection systems is related to planning. If a pipe
is laid down to a fringe area where county zoning maps indicate only
limited development is going to be permitted, its size is gauged to that
kind of development. But if the zoning is changed later and three times
as many houses are hooked up to the line as were originally envisioned,
trouble results. Rock Creek is heavily affected by such sewage, and the
chances are that the situation is much worse on many other urban
drainways, for their longstanding degradation or sheer disappearance
from view has lost them the alert defenders who watch over Rock Creek in
its pleasant valley.
Out of the storm sewers whether combined or separate, off of the roads
and streambanks and hillsides, down the urban tributaries or directly
overland into the estuary, comes still another big jolt of organic and
bacterial pollution every time there is a heavy rain. This is surface
runoff, the washings of the street and parks and sidewalks and rooftops.
Besides debris, it contains vast hordes of bacteria and many kinds of
organic oxygen-demanding substances, of which animal droppings are only
one easily definable example. Around a city the size of the Washington
metropolis, this runoff would constitute a worrisome pollution problem
even if the matter of sanitary wastes were thoroughly in control.
[Illustration]
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
shores--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
shores 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 shoreline 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 unassimilated 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.
[Illustration]
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 municipal 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 pass 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
quantities 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 accumulation 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
institutions 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.
[Illustration]
[Illustration]
Junk and debris of all descriptions infest the metropolitan river,
floating about, washing onto the shores, 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.