Social economy and water resources utilization

Animal husbandry is the main industry in the upper reaches of Heihe River Basin, which is developing rapidly. The middle reaches are located in the throat of the ancient Silk Road and the present Eurasian Continental Bridge, where successive regimes settled and defended their borders. Agriculture and animal husbandry has a long history and is an important commodity grain, vegetable and seed production base in the western region. The downstream Ejina Oasis is an important ecological barrier in northern China.

In the Heihe River Basin, * * * has 1 1 counties (cities, banners), Qilian County and Sunan County are located in the upper reaches, Shandan, Minle, Zhangye, Linze, Gao Tai, Jiayuguan and Jiuquan are located in the middle reaches, and Jinta County and Ejina Banner are located in the lower reaches. There are people in the whole basin 184.05× 104, including 3.6% in the upper reaches of mountains, 88.2% in the middle reaches of plains, 7.3% in the lower reaches of Jinta and 0.9% in Ejina.

The existing irrigation area (including forest and grassland) in the area is 30.99× 104 hm2, and the dry land is 6.9 1× 104 hm2. 198 The total grain output was 124.86× 104 t, and 99% of the grain was produced in the middle reaches plain and Jinta irrigation area. At present, there are 427. 1× 104 livestock in the whole region, and nearly 63% of the livestock are concentrated in the upstream pastoral areas (Qilian County and Sunan County). 1998 The gross national product in the basin is 142.96× 108 yuan, of which 96% is produced in the middle reaches of the plain and Jinta County (Table 1-4).

Table 1-4 Social and Economic Status Indicators of Heihe River Basin

Heihe river basin has a long history of development. Since the Han Dynasty, agriculture and animal husbandry have developed alternately. During the Han, Tang and Xixia Dynasties, immigrants settled in fields. Five canals including Yingke, Daman, Xiaoman, Daguan and Jiaguan were built in the south of Zhangye in the Tang Dynasty. In Qing Dynasty, irrigation areas in Gao Tai, Minle and Shandan began to be developed. Since the founding of New China, especially since the mid-1960s, large-scale water conservancy projects have been carried out in Heihe River Basin, and more than 100 reservoirs have been built successively (Figure 1- 14a). Build a large reservoir in front of the mountain to store surface runoff water resources in mountainous areas and accelerate the development and utilization of water resources in the middle reaches. With the increase of population (figure 1- 14b) and the expansion of agricultural irrigation area year by year (figure1-kloc-0/4c), the amount of water flowing into the downstream area is decreasing year by year, the rivers and lakes are dried up, the groundwater level continues to drop, the ecological environment in Ejina is rapidly deteriorating, grassland degradation and sandstorms are further aggravated, and the contradiction of inter-provincial water use is more prominent.

Figure 1- 14 development process of reservoir (a), population (b) and irrigation area (c) in Heihe river basin.

Second, the present situation of water resources development and utilization

In Heihe river basin, most of the existing water diversion channels were dug from Han and Tang dynasties to Ming and Qing dynasties, and the development and utilization of water resources were mainly concentrated in the middle reaches of the plain and the Jinta irrigation area in the lower reaches. At present, there are 98 small and medium-sized reservoirs with a total storage capacity of 3.4× 108 m3, including 22 reservoirs in mountainous areas with an annual output of 5× 108 m3. The artificial oasis is basically covered by the diversion canal network. The main canal and branch canal are 965,438+00, with a total length of 4500 km. The lining rate of root canal is 50% ~ 70%. The annual water volume of rivers and springs is 32.6× 108 m3, and the utilization rate of surface water is about 80%.

The total water consumption in Heihe River Basin is 3 1.47× 108 m3/a, of which the upstream is 0.4 1× 108 m3/a, the midstream is 25.98× 108 m3/a and the downstream is 5.08×.

Citing spring water is the main form of groundwater development and utilization, which is concentrated in the middle reaches of Heihe River and Jinta Irrigation District. At present, the cited amount of spring water is (7 ~ 10) × 108m3/a, and the cited amount of spring water has increased or decreased due to the changes of mountains and rivers.

At present, there are more than 8,000 mining wells in Heihe River Basin, and the annual groundwater exploitation amount is about 5× 108 m3, and the utilization rate of groundwater exploitation is 13.5%. Groundwater exploitation is mainly from April to June every year, which is in the period of insufficient river flow and agricultural irrigation. The industrial water and domestic water in cities and towns are mainly based on the exploitation of groundwater.