Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1916-07-27

Geological Survey has Just issued itu
latest report on the water-flow of the
Colorado River and It's tributaries
Hundreds OF tables showing tho dis
charge OF hundreds of streams in sec
ond-fcc, Of water fill the pages Look
ing at the solid columns OF figures. n
plain citizen was moved to ask an OF
ficer of the Survey a question.
What Is the purpose of'carrying on
this sort OF measurement daily year
after year" he queried WIZ do
YOU keep big force Of men reading
gauges and estimating velccitics in
me same place on the same river for
fifteen years? Why don't you measure
stream and have done with it?"
The officer told him story II in
spected dam down In the far South
west few years ago., ne said. 1T
was an excellent piece Of work. we'll
constructed and perfectly able TO hold
the waters that II was designed 10
impound. There was only one thing
the matter with It, The water that II
should have backed up wasn't there
The lake above H. made by Its building.
was as dry as the great Sahara II Vas
dam without water. blocking an
empty channel They were actually
pumping water into tho reservoir in an
attempt TO keep 4 few trees alive. There
hadn't been enough rain 10 run down
III. SUES VI NIlc t!nDtuktneCl Tor eight
years.
Why did they build dam Their.
them" the qucstioner wanted TO know
oh. when they looked over the site
and decided to build, there was plenty
OF water--a fine river. 1t looked Ike
a good thing. There had been plenty
water In the river for years past.
Everybody in the neighborhood re.
garded the river permanent in
su:ution. 1t may flow In the future
again freely enough. But q series OF
dry years happened TO strike the re-
:ion. and for those years the river
disappeared"
OF course dam in such {, situation
is almost dead loss To be Of any
use TO settlers and farmers n water
supply must be dependable. II must be
there every year: because the Colntr:
cannot afford TO wait eight years be.
tween crops. And In the land OF little
ram where irrigation is the only
method OF farming, difference Of five
or six inches In annual rain fan. that
would hc unnoticed In the eastern half
OF the continent. Is the difference be-
tween ample water and drought
Long Observation Necc.sary.
ne only way 10 determine with real
Sciehtihc accuracy Just what may he
expected from a river system I'm tho
way of wa,cr-supply is to measure
me no" OF the main stream and its
tributaries day in and day out for a
long period OF years. Climatic changes
seem to move in long, slow cycles
only by extended observations can tho
rear available water-supply be deter
mined with the reliability that is es-
scntial before capital should be riskcd
In schemes for reclamation, power and
other development. And this extended
observation Is the work that the Geo
logical Survey Is carrying on in its
stream measurements at 800 stations.
\ case like that OF the dam whose
river went dry and whose sides were
hardly dampencd with rain in eight
years Is Of course extreme and cXccp-
tional a much smaller variation in
the amount OF water between wet
years and dry years can make just
as effective difference between profit
and loss. Ii dam is built for irri-
CATION ON n basis OF certain extremes
OF variation in water-supply within
hve or six years, and the seventh or
eighth year brings n new mark. lower
than any previously recorded GER
tain percentage of the crops dependent
on the reservoir will inevitably be
lost. a certain percentage of the land
reclaimed VIII for that year at least
go back to desert. The same thing
holds true of dams built for power
purposes. If mill is built with the
expectation OF drawing n certain mini
mum power supply from the penned
water. and the actual flow runs below
that minimum for even n short time
each year, the investment is likely TO
prove losing one.
Problems Differ Widely.
IN the dry West. the problem is one
of determining by long observation
just how little water will flow in a
dry year. In the East. the chief point
to he determined is usually just tho
opposite--how much water must be
guarded against in n year of flood.
With the sastrous foods in tho
Southeastern States just beginning to
recede. leaving their wake OF damage
and death behind them. there is n
concrete example of the necessity OF
| determining with scientific accuracy
| just what stream-f flow is likely TO be-
Large and destructive floods iE some
| part OF the country are matters 81
annual occurrence. Flood damage In
| the United States In estimated at more
| than slo0000,000 year. a certain part
| OF this. perhaps q considerable part.
!; Is popularity considered as unavoida
| BILE But food prevention is a recog-
| nlzed Junction OF tho domestic duties
! Of government. a great deal of tho
| damage is undoubtedly due to human
| encroachments on the danger zone Of
| the larger rivers. Wharves and docks,
| even streets and cities, are built on
land that Is In ordinary years we'll
J out OF harms way. but that lies. In
| flood years, In tho rivers abnormal
fluctuations of river and It's tribu-
taries for decades is 1t possible to de-
| termine In advance, when selecting
sites for new developments in build
| ing, whether the land in question Is
| liable to inundation or not.
The measurement OF stream-how is
becoming an increasingly important