a lot of dedicated and expert attention and some
rectification. Thus anyone who travels up and down the river and its
tributaries finds many miles of pleasant flowing streams capable of
sustaining fish and the other things that are supposed to live in and
around water, and fit to soothe frayed nerves.

He will find a lot of grubby and unsoothing stretches too, extensive in
places, and even in the pleasant streams troubles exist that are
invisible to the eye. There is little to be complacent about, for
threats are multiplying rather than fading, and some parts of the
Potomac river system already need more than help; they need
resurrection.

[Illustration]

The Basin has several standard sorts of pollution, often found in one
combination or another. Chemical contamination occurs along the North
Branch, in areas where pesticides and other economic poisons get into
the stream system, and in spots and stretches where specific industrial
wastes create local problems. There is much and widespread pollution
through organic wastes--often sewage solids, but not always--whose
breakdown by natural processes may demand so much oxygen that a stream
has little or none left over to maintain aquatic life and "stay alive."

Sometimes associated with organic wastes and sometimes entering the
river system otherwise are dangerous bacteria, and also the so-called
"nutrients"--dissolved fertilizing agents that can stimulate excessive
growth of algae or weeds in the water to the detriment of other forms of
life, often to such a degree that these plants' death and decay sets off
a whole new cycle of oxygen demand. And there is sediment washed off the
land, which clouds the water and settles out into a smothering cloak on
the bottom, building up in quiet stretches into ugly and damaging mud
banks and shoals.

Troubles above the Fall Line

Pollution of the Potomac begins at or near its traditional source, the
tiny Appalachian spring at the head of the North Branch where in 1746
Thomas Lord Fairfax's surveyors set an inscribed stone to mark the
northwestern corner of that possessive nobleman's vast holdings.
Abandoned strip coal mines lie within sight of the spot, and it is
doubtful that the infant river trickles more than a few yards before
receiving its first injection of the acidic mixture of substances that
springs and seeps and runoff water extract from bared coal strata and
the mines' spoil heaps and carry down to the streamlet they