The Julesburg grit-advocate., 1911-11-23
THE PREATlc WATERS
u the Undesground Waters Suf.
fieisat for lrriSatioa Purposes
ERASMUS HAWORTH.

~ ERASMUS HAwORTH-
MNo one knows the amount of ground
water underlying our great plains region
and it is doubtful if anyone ever will.
However, great deal is known Oh the
subject. We have hundreds. yes
thousands cf wells drawing water from
it. Some of them have been exhaust
cd. while others have been pumpedfrom
as rapidly as a fifty horse power engine
could operate without producing any ap-
preciable effect upon the amount of
water the well could yield. 1t is diff
ticult to judge of the capacity of
well even by such operations az these.
Should well reach an underground
ridge Of the Cretaceous floor it may be
entirely barren from the start. Yet all
they demonstrate is that they chance
to be located over ridge in the floor
an Island so to speak in the under
ground lake. Should a well be sunk
into an underground valley where the
water-bearing sa-d is hundred feet
thick, the water pumped for 4 year at
the rate of a thousand gallous minute,
it would by no means show how great
the ground water is eveniu that locality,
Should the well become exhausted by the
pumping it might mean that that par
ticular pool of water was exhausted,
but most probably it would mean that
the pump had drawn the water f,ster
than it could flow through the adjacent
sand in order to reach the well. Bat
we know there are vast quantit:es Of
water. Hundreds upcr. huudreds OF
wells have been pumps from as CON
: oslsly rs tie wind would give motion
t. machinery for from one to five years
without showing any Indication OF
diminution in the supply. Our estimates
of the amount of the ground water. it
would seem, must be based uyou re.
suits obtained from tgo lines OF iu-
vestgation, neither Of which can ever
be made exhaustive. One Of these is
the amount OF water which can actually
be lifted to the surface from belo,v.
1t vii! be understood by all thinking
people that the only way the question
could ever be answered by this means
would be to have a sufficient aum! ~ Of
pumps to entirely exhaust the st;,.nlv
of water, which is impracticable. and
equal undesirable We're it practicable
The other line OF investigation is to
determine the source OF water ard to
form an estimate of the amount in
that way. This. too, has already been
shown to be impractic.he If an ex-
haustive inquiry is desired Ii would
be be difficult to estiiaate. excepting
approximately, the proportion OF
precipitation on the great plains which
reaches the undcraow But it is much
more difficult to determine the amount
of water available from other sources.
Should this be confined entirely to the
Dakato sandstone, which is not prob
able, TO way is known at present of
= Ytermining even Approximately the
Mnt of available water. The limit
i. precipitation Of the plains averaging
from l6 to 20 inches per annum, vary
ing with location, wouid be entirely
evaporated were it continuously exposed
to the surface. But the methods en-
ployed by nature considerable pro-
portion of this precipitation soon pas
ses downward beyond the the reach of
evaporation. On the basis of twelve
inches of water being all that is neces-
sary to add each season, if six inches
of water annually joins the underground
water it would be possible to irrigate
fifty percent of the whole area: if three
inches of the rainfall is saved annually
twenty-five percent could be irrigated;
while if only one inch annually of the
rainfall is saved 81 percent of the
whole territory could be irrigated.
Regarding the artesian water supply
the most important question is the rate
supply rather than the amount now ac-
cumulated in the underground reser-
voirs. The volumn of water now stor-
ed in the Tertiary sands ard gravel
can be of only temporary interest, can
serve only temporary wants. Itis the
annual addition to the available water
that is of the greatest Importance, for
it represents the amoun: which can be
perpetually used each year. When we
consider relatively large areas covered
by surface sands which absorb almost
all the precipitations and the large
number of small streams which pour
their water out upon the sand hills and
plands during the time of ireshets, it