关键词: 黑河流域, 水文, 生态环境, 变化

Abstract: The purpose of study is to investigate the influences of water resource developm ent on the ecological environment in the a rid regions of north west China with Heihe River basin as an exam ple.During late 50 yea rs, the Heihe Riv er system changed heavily:the discharge of the low er reaches of the river decreased seriously; m ore than 30 tributaries and its terminal lakes have dried up.Such hydro logical change results in the deg rada tion of the ecological environment, secondary salini zation and land desertification in whole basin.Since 1949 the water consumption in the middle reaches area of the basin has increased by 19 times; the area of oasis has added by 89.5%; thus, the discharg e in the lower reaches of the river has reduced by 51%; the spring water output has reduced by 22.8%; mineralization deg ree of surface water a nd shallow ground water in the middle and low reaches have been increasing due to varia tions of hydrological condition and redistribution of water resources.Furthermo re, both surface water and g ro undwa ter were seriously polluted.In the middle section of the riv er basin so me 43.18×10⁴ hm² of g rassland degraded seriously; 0.93×10⁴ hm² of forest have been destro yed and the desertified land has increased to 5.35×10⁴ hm².Inthe lower reaches of the riv er basin, deg raded vegetation has reached 27.18×10⁴ hm² and land desertification is ex panding at arate of (1.1~1.3)×10⁴ hm² per year.Human activities are the main reason responsible for these changes.

Key words: Heihe River basin, Hydrology, Ecological environment, Change