ituation--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 masses 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 space in
reservoirs becoming more and more expensive precisely as flood
protection does. Flow augmentation is no substitute for good treatment,
but a valuable adjunct.

In the record drought summer of 1966 the South Fork of the Shenandoah,
heavily polluted with municipal 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