The McArthur enquirer. (M'arthur, Vinton County, Ohio) 1873-1884, 1873-03-19
miscellaneous Reading.
THE RIVER Po.
Character Of the Stream-D Danger
from Floods.

|
from Floods.
1t is hard to get at the his
torical records of the river more
than two thousand years ago,
though we may form a good
guess as to its earlier geolog-
ical history, Within the his
torlcal period extensive lakes
and marshes (some of them.
probebly old sea lagoons) lay
Within its plains, since gradl-
ally filed with sediment by pc
riodieal foods. Great lines Of
dikes, partly Of unknown am
tiqu.ty, border the yinding riY-
er for a length of about two
hundred miles from Piacenza to
its mouth, and throughout this
course it's breadth varies from
| four to six hundred yards.
Through all its many winnings,
from Chivasso downward, allu,
vial islands diversity its course,
and deserted channels here
and there mark the ancient alb
erations of the river. The
guard against the devastating
effect Of floods, and to check
such alterations, the dikes were
raised; and in this contest of
man with nature, the result
has been that the alluvial flats
IN either side of the river out
side the dikes have for long
received but little addition Of
surface sediment, and their
level is nearly stationary. 1t
thus happens that the most
IF the sediment that in old
times would have been spread
by overAows across the land,
is now hurried along towards
.he Adriatic, there, with the
help of the Adige steadily to
advance the far-spreading al
luvial flats that form tho delta
of the TWO rivers. AS the
9mbanking of the river went
)n from age to age, so just in
proportion has the ANIMAL
amount Of the formation Of the
!elta been accelerated. The
town Of Adria, a seaport OF
the Adriatic in the reign Of Au-
5ustus, is now fourteen miles
from the shore, and the an
3ient lagoon of Ravenna has
long since been filled up, chief
Iy by the mud brought down
oy an ancient arm Of the Po.
3ut the confined river, unable
5p annual floods to dispose Of
part Of its sediment, just as
he dikes were increased in
height, gradually raised its bot
.om by the deposition there of
portion Of the transported
material, so that to prevent
its overflow it is said that the
9mbankments have been raised
so high that at Ravenna the
full flooded river often runs
higher than the tops Of the
houses, and the safety Of the
neighboring country is in con-
slant state Of anxiety to the
inhabitants. All these dangers
have been much increased by.
he wanton destruction Of the
forests of the Alps and Appen-
mines, for when the shelter OF
the wood is gone, the heavy
rains of summer easily. washed
the soil from the slopes down
into the river, and many an
upland pasture has by this
process been turned into bare
rock. In this way it happens
that during the historical pc
riod the quantity of detritus
borne onward by the Pc has
much increased; the level Of
its bottom, is, therefore, more
rapidly raised, and whereas be-
tween the years 1900 and 1000
the delta advanced on an aver
age only about TWENTY-FIVE yards
a year, from the year 1900 to
the year 1900 the increase has
been more than seventy yards
At last a selson comes like
the present, when long contin-
ued raines falls alike on mount
aims and plans, and the floods
swollen by the rapidly thawing
glaciers, steadily increase the
volume Of the rivers, till at
length they rise to the very
brim Of their embankmeuts;
and in spite of the long con-