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river beds are altogether inadequate to carry off the flood. Thus, while the
Mahanadi alone pours down 1,800,000 cubic feet per second in the height of
the rains, the whole of its distributaries in the Orissa delta can only discharge
897,449 cubic feet per second. It follows, therefore, that only one half of the
waters thus brought down find an outlet through the deltaic distributaries to
the sea. The other half bursts over the banks, and sweeps across the country.
"The Mahanadi," as pointed out by Dr. Hunter in his Orissa, "illustrates
in a striking manner the biography of a great Indian river." Rising in
Central India, 520 miles off, it collects the rainfall of 45,000 square miles,
and pours down on the Orissa delta through a narrow gorge just above
Cuttack city. In its first stage it runs on a lower level than the surrounding
country, winding through mountain passes and skirting the base of the hills.
During this long part of its career it receives innumerable tributaries from the
higher country on both banks. So far it answers to our common English idea of
a river. But no sooner does it reach the delta than its whole life changes.
Instead of running along the lowest ground, it finds itself hoisted upon its own
deposits of silt, its banks gradually forming ridges, which rise above the adjacent
country. Instead of receiving affluents, it shoots forth distributaries. The silt
gradually accumlates in the bed and on its margins, until its channel shallows
and its capacity as an outlet for the waters which pour into it from above
diminishes. The same process goes on in every one of the hundred distributaries
into which the parent stream breaks up; and as the beds grow more shallow,
their total discharging power becomes less and less adequate to carry off the
water-supply to the sea. As the rivers in the delta thus gradually build
themselves up into high-level canals so the lowest levels lie about half
way between each set of their distributaries. The country, in fact, slopes
gently downward from the river banks, and in time of flood the overflow
is unable to make its way back again into the river. The waters stand
deep upon the harvest fields long after the main channels have run down.
They slowly search out the lines of drainage, accumulating in stag-
nant swamps, drowning the crops, and poisoning the air with malaria,
until they dry up, or at last reach the sea. Even in periods of quiescence
the rivers form a complicated net-work of channels, which crawl eastward
by innumerable bifurcations, interlacings, and temporary rejunctions and
divergencies," Besides the copious water-supply, Orissa has a local rainfall
of 621/2 inches per annum. Nevertheless, the uncontrolled state of the
water-supply has subjected the country from time immemorial to droughts no
less than to inundations.
The tributary hill states of Orissa, 19 in number, which form the
mountainous back ground of this division of the Bengal Province, occupy a
succession of ranges rolling backwards towards Central India. They furnish
no cholora statistics, and therefore require no description here.
B 2