The current water resources in Shiyang River basin are not sufficient for the current
demand of industry, agriculture and economic development. For a typical year, when
probability of exceedence p = 50% of annual rainfall, the total demand of water is
29.43 × 108
m3
, but the total available amount is 26.61 × 108
m3
(including surface and
ground water resources). The total water shortage is therefore 2.82 × 108
m3
. When
p = 75%, the total available can be 24.92 × 108
m3
, and the total shortage will be
4.51 × 108
m3
. When 4 × 108
m3
of excessively exploited groundwater is added, the
shortage amount of water resources reaches 6.82 × 108
m3
(p = 50%) or 8.51 × 108
m3p = 75%). If the whole area of 28.52 × 104
ha land in the basin adopts the measures of
limiting irrigation quota and water saving irrigation technologies, net irrigation
requirement is estimated as 3750 m3
ha-1. And if the water conveyance efficiency for
canal system is improved as 0.62, the water savings by agriculture in Shiyang River
basin can be of the order of 8 × 108
m3
. That is, the water demand cannot be met only
in drought years.
The shortage of water in the region may be relieved by inter-basin diversion and a
diversion project from Liutiao River (at Gulang in Fig. 1) to Hongshui River is being
built at present. The Jingdian project (at Jingtai in Fig. 1), which is lifting and diverting
water from the Yellow River, can transfer 1.0 × 108
m3
water to Hongyashan reservoir
in Minqin and solve the problem of water shortage for 1 × 104
ha land, although it
cannot solve the water shortage problem in the whole Shiyang River basin.
More projects have been envisaged to solve the region’s water shortage, such as
diverting water from the Da Tong River in Qinghai province to the Xida River.