PUB00068

• Year: 1952
• Title: A Hundred Years of Irrigatioin in Colorado, 100 Years of Organized and Continuous Irrigation
• Author: CWCB
• Description: Irrigation history of Colorado
• Publications - Doc Type: Historical

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Not all are so favored. And then there are scattered small areas where
the pumping isso light that the effect on the water table is insignificant.
Also there are wells' adjacent to streams where water flow is frequent
enough to replenish any withdrawals.

There are at least two places under canals, however, where the
balance between replenishment and pumping draft is very delicate. One of
these is near Wellington where pumping has been on the increase for 15
or 20 years and canal water inadequate. Tne water table recedes over
periods of 4 or 5 years at a time and the few favorable years have never
brought it back to normal. Prospect Valley is another such place under
canals. For a period of 9 years after pumping started in 1932 the water
table there kept going down until in some places it was as much as 16
feet lower. Then in 1942 it began to rise and by 1950 had recovered almost
completely except at one end of the valley. In 1950 and 1951 it went down
again about 6 feet. These delicate balances keep the residents nervous.

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There are two places entirely dependent on groundwater for.
irrigation where the downward trend of the water table has been persistent.
Along Beaver Creek near Gary the decline started in 1942 and has now
amounted to 10 feet. In Bijou Valley, where about 30,000 acres are being
irrigated, a similar lowering is taking place which started in 1937. These
places get replenishment only from flood flows which have not been
sufficient to prevent a constant lowering. Residents in these areas of
course are greatly concerned. A third place may be mentioned, one that is
beginning to show distress symptoms, is in Box Elder Valley north of
'Natkins. It is too soon yet to be certain wnether the downward trend
there is a .temporary one or not. .

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Water tables have fallen in many places due to overpumping. We
associate this situation with California and more recently Arizona but
there are many other places. The High-Plains of Texas is one of them.
California has been giving much attention to the artificial sinking of
water to halt the decline. Arizona's Salt River Valley and Casa Grande
Valley are examples of recent over draught during a period of extreme
drought. In the Casa Grande Valley there has been an annual lowering for
over 20 years. It was small at first but lately it has been on the order
of 8 feet with a total lowering of about 80 feet. Under recent legislation
the area has been declared critical and drilling has been stopped. We have
been given a warning that 'it can happen here in Colorado and we should lend
an ear. There are many places where a lowering of even 20 or 30 feet would
'put the pumps out of business.

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I should not omit from this discussion something about the value of
ground water to the economy of the State. We have no accurate way of
getting at the total amount that is being pumped but we can make some
intelligent guesses. There is a clue in the amount of power consumed for
irrigation pumping. We know this reasonably close but it does not account
for the engine drives. In addition there are the industrial, municipal
and domestic uses. An overall state irrigation load of 60,000,000 kilowatt
hours is being reached. It takes about 1 kwhr. to raise an acre-foot of
water 1 foot at 100 percent efficiency. Let us suppose the average lift
to be 60 feet and the overall efficiency 40 percent~ These are liberal

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