河西内陆干旱区主要河流出山径流特征及变化趋势分析

Changing Trend and Features of the Runoff from Mountain Areas of Some Main Rivers in the Hexi Inland Region

根据相关水文气象台站的降水、气温和径流观测资料 ,分析了以黑河、昌马河、西营河等河流为代表的河西内陆区出山径流的变化特征和规律 .研究表明 ,河西内陆干旱区诸河流出山口径流的季节变化主要受地理位置和河流补给来源的影响 ,而年际变幅则受山区降水量年际变幅的影响十分明显 .总体上讲 ,本区出山径流变化相对稳定 .区内梨园河以西河流水量处于上升阶段 ,梨园河以东的河流则处于下降的阶段 ;以黑河干流莺落峡水文站年径流为代表的中部地区出山口径流目前正处于 1 990年开始的枯水段的上升段 .预计今后若干年内 ,河西内陆干旱区东段河流出山口径流的变化以偏枯为主 ,中段、西段河流出山口径流变化以平水或平水偏丰为主 .

The Hexi inland region, 37°17′～42°18′N, and 92°23′～104°12′E, is located in the periphery of the Tibetan Plateau and the east of the northwestern arid region of China. The region is an important development area of Gansu Province, with a total area of 2.15×10 6 km 2 . The key to sustainable development in the region is water. Because of water lacking the eco-environment is very vulnerable. The Qilian Mountains is the source region of the Hexi inland arid region. There is about 70×10 8 m 3 of surface water from this area flowing to the corridor plain area each year, which is a basic guarantee for the economy development in the Hexi region. The renewable water resources from the Qilian Mountains is not only an important natural wealth for development of agriculture, forestry and animal husbandry, but also a significant factor for maintaining ecological balance and environment conservation in the arid zone. There have been a decreasing trend of streamflow in the northwestern arid region in China since the 20th century as the climate warming. The changing trend behaves differently from place to place, though it is universal. Water is short in the Hexi region, so to its future variation should pay more attention. Measured data of precipitation, temperature and discharge from meteorological and hydrometric stations in the studied basins were used for researching the changing trend and features of the runoff from the mountain areas of some main rivers in the region. The result shows that the variation of the runoff from the mountain areas of the rivers has the following features: (1) Seasonal variation of runoff from the mountain areas of the main rivers in the Hexi region is mainly regulated by the river's geographical location and supply sources; mainly dependent on precipitation in the Qilian Mountain. (2) Yearly variation of the runoff of the rivers located in the west of the Liyuan River basin in the region is affected mainly by precipitation in the Qilian mountainous. (3) The long-term trend of runoff of the rivers located in the west of the Liyuan river basin is increasing; the runoff of rivers located in the east of the Liyuan River basin is decreasing; the runoff of the central rivers, represented by the Heihe River, is slowly increasing from a low water phase which began from 1990. (4) It is predicted that the runoff of the rivers located in the east of the the region will be decreasing; the runoff of rivers in the central and western parts will be steady or increasing.