Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-03-23
BACKGROUND OF EVENTS
BY PAUL Y. COLLINS.

1.-THE water within the river channel
does no damage and flows to the Gulf
with the most efficiency because OF It's
high velocities It should be kept
within the channel as long as possible
The excess above the safe carrying
capacity must be spilled through safety
valves"
That means that regularly built
openings must be provided as substi-
tutes for bursting crevasses and the ex-
cess water permitted to flow over the
adjoining low land-nostly swamp and
cut-over forest. Says the engineers
report:
THE existing project provides for
protecting the good lands bordering the
Mississippi River against the maximum
flood predicted as possible. This maxi
NUM- flood was predicted by the bsst
experts on the subject. who said that
1t might occur on the average only once
in 200 years. 1t is a flood which. II
confined, is computed to produce stage
of from SO to Sc feet at Cairo lcorre-
spending to a discharge of from 2,250.-
900 to 2.450.000 second feet; stage,
If confined, of "a feet at Arkansas City
corresponding to an outflow OF e.
$4,000 second feet), and flood with
discharge at the mouth of the Red
River of about 100000 second feet.
Above Cairo the project is to be
confined between the riverside levees,
since it can be thus confined with levees
not Of excessive height--about 20 feet"
This plan to let the river south Of
Cairo spread out when there Is a super
flood contemplates protecting levees at
the outer edge of the wide basin.
Says the report:
The foodway from Cairo to New
Madrid will have minimum width of
miles. The width between the pro-
tecting levees on the Boeuf Basin will
be from 10 to IS miles wide. and in the
Atchafalaya Basin will be from IL TO Is
miles wide"
There are enthusiastic advocates of
various special projects to abolish food
troubles. Among these are the special
champions Of forestation. who attribute
most of our flood troubles to the cutting
of Of the primeval forests: yet history
shows that there we're great foods be-
fore the white man arrived. Forestry Is
important in preventing the washing
away of soil near the heads of the
streams. but trees are of little use in
controlling the overlooking river. Says
Raphael Zon, director, Lake States For
est Experiment Station:
Soils covered with forests can take
up quantity of water corresponding TO
precipitation Of Ole inch, or, in very
favorable conditions, 024 inches at
most. A cover Of moss can store up
from 018 to 0.39 inches. These
amounts are insignificant when COM
pared to the enormous quantities Of
precipitation that cause excessive
floods. Over 20 inches of rain fell In "a
consecutive hours at some points In the
storm Of July, 1916. in the Blue Ridge
Of North Carolina. that inundated the
French Broad, Catawba and other river
basins, and caused destruction esti-
mated in the millions of dollars. A tor
rental rainfall of IA inches within a
short period was recorded this Spring
in the lower Mississippi Valley. Such
enormous quantities of water are ut
terly beyond the capacity Of the forest
flood to absorb"
Conservation reservoirs may take the
overflow for limited regions, such as the
section of Ohio serving the Great Miami
River. which caused the DAYTON flood of
1918, but they are impracticable for 30
on account of the prohibitive cost of
the land required II is decided that 1t
were better to utilize only the COM
paratively cheap swamp and forest
land along the main channel of the
river, for spillways and rln-offS.
1t Is curious to note that scientists
have computed the total rainfall since
rains began to fall after creation of the
world. Basing estimates of rainfall upon
the sedimentary rocks. It - calculated,
according to Bowie of the United States
Coast and Geodetic Survey. that 1t be-
gan to rain 1,500, 900, 900 years ago, and
that the average throughout the world
and through that billion and a half
years has been 80 inches a year. That
Is enough to cover the whole world with
an ocean 750,000.000 miles deep, or eight
times the distance from earth to sun.
That is about half million times as
much water as exists on the earth, so,
like last years automobile. all the water
Of the earth Is second hand"
Since the beginning of the Christian
era, the 80 inches per year of rainfall
has amounted to an ocean only one mile
in depth. All the stock of water on
earth, II spread out evenly all over land
and sea, would be IL miles deep. hence
1t has been evaporated and reused In
rainfall since Christ was born. only to
an amount of less than half the total
supply. How dry we arel"
Gconyrisht, 1s2s, BE- psul 2. ccrinAl