Page 92 - Arabian Studies (V)

82 Arabian Studies V
average irrigation supply amounts to some 0.22 x 106m.3 on a typical
vegetable farm unit, 0.17 x 10-6m.3 on a typical vcgctablc-orchard-
foragc farm unit and 0.13 x 106m.3 on a typical orchard-forage farm
unit. By relating these data to the total number of farms of different
categories, the total gross groundwater extraction for irrigation is
calculated to be 51 x Kftn.Yannum which is within 10 per cent of the
estimate arrived at by a separate water consumption inventory carried
out during the same period. Total extraction for irrigation is therefore
of the order of 50-55 x 106m.3 per annum of which an estimated 20 per
cent is returned to groundwater as ‘irrigation return’ giving a net
consumption of some 43 x 106m.3 per annum, equivalent to a mean
depth of 2.28m. per annum. Crop water requirements range from
0.7m. fordatesto 1.0m.perannumforalfalfaandfrom0.3mto0.7m.
for seasonal vegetable crops and it is estimated that crop water
requirements averages 1.0m. per annum over the net cultivated area,
indicating that irrgation efficiency is of the order of 45 per cent. If net
consumptive use is compared to gross extraction then only 35 per cent
of water pumped is being effectively used by crops, the remainder
being lost in transmission, in the fields and by percolation back to the
ground. The present cost of water (Mitra, 1976a) to private farms is
QR0.05 per cubic meter and the value QR0.60, giving a net return of
QR0.55/m.3.

Conclusion

Qatar, in common with many of the Gulf states, has over the past few
n years enjoyed unprecedented economic growth which in large part has
resulted merely from transforming oil into financial assets. However,
in attempting to diversify the economy to attain some measure of self-
!'
sufficiency, particularly in food production, the country is faced with
' meagre and declining soil and water resources set in a hostile climatic
environment. The total arable soils in the country cover some 29,600
ha. of which 1,975 ha are at present under cultivation and an equal
area has already been abandoned as a result of excessive water use and
inefficient irrigation. Water is being extracted f rom the main * floating
lens’ aquifer system at nearly twice the rate of replenishment and the
quality is deteriorating at a rate of 5 per cent per annum, caused by sea
water intrusion and upward diffusion of deeper saline water.
Although the cultivated area represents only 0.17 per cent of the
arable soil of the country the amount of water being extracted to
irrigate this limited area is disproportionately large, of which only
one-third is effectively utilised by crops. Any expansion of irrigated
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agriculture by prevailing practices and standards cannot therefore be
contemplated without seriously overdrawing groundwater reserves

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