|
Black Water
by Jan Edwards
In a previous post, dead
water was investigated. But have you ever heard of
the term black water when someone
was
describing a
particular set of circumstances that happen once in
a while on the
San Bernard River? Let’s
investigate black water.
If you look it
up in Wikipedia (the free internet
encyclopedia), you’ll find two different meanings
for black water. The first definition defines black
water waste. This is a relatively new term which is
used to describe water containing fecal matter and
urine. It is also known as “brown” or “foul” water
or…pee u…sewage. It differs from grey water which
contains the residues of the washing process. In
this case, black water is heavily polluted and
difficult to treat because of the high
concentrations of mostly ORGANIC pollution. We HOPE
we never have to describe the San Bernard River in
such terms.
Then, there are black
water rivers which contain waters colored like black
tea to coffee. According to Wikipedia,
most major rivers
designated as black water rivers are in the
Amazon River
system and in the Southern United States.
The black water river is one with a deep slow-moving
channel that flows through forested
swamps and wetlands. The
color in the river results from the leaching of
tannins from the decaying leaves of vegetation that
drops in the river. Does this sound like the San
Bernard in the summertime to you?
Black and white
waters differ quite a bit in their ionic
composition. Black waters have ionic concentrations
just a bit above rainwater – but are much more
acidic which gives black water more concentrations
of aluminum than white waters. This has major
ecological implications. Some animal groups, like
snails and oysters, need calcium to build their
shells – and calcium is NOT abundant in black
waters.
Black and white
water also differ greatly in the planktonic flora
and fauna that live in them. Seems the black water
held far greater numbers of rotifers but fewer
crustaceans and mites. The crustaceans are food for
larval fish. So, the zones where black and white
waters mix tend to have high numbers of animals.
So, no matter how you
view it, black water is an ecological occurrence. It
does not necessarily have to be a bad thing. But
when you stand on the banks of the
San Bernard
River after a drought in
the summertime, and there comes a summer deluge of
rain that lasts for a while, you may witness what
the old salts at the end of the river
describe as the San Bernard’s personal version of
black water. Because of the amount of
agricultural endeavors
and cattle “taking care of their business”, the
deluge will wash more than the normal amount of
organic materials into the river, then it starts to
mix and ferment with the river’s normal tannic
compostion – and it will actually turn black – and
STINK!!! When that happens, nothing can live in the
river – fish, crabs and oysters die – and all you
can do is wait for another rain to “flush” the
system. But with the river mouth closed – if we get
it, we might have black water for a while.
Anyone know the number
for River Rooter? |
