中文摘要：

大量实测资料及综合研究表明，在内陆干旱区人类活动对水循环变异影响状况具有独特的标识特征，且具有一定的警示性和重要指导意义。当水循环中研究区径流量实测值离均系数小于0时，表明这时该水循环过程已失去了天然状态特征，实测径流量累计过程线明显偏离天然径流量累计过程线。在年内，每年的5月份受春旱农灌大量引用出山地表径流水量影响，地表径流量及其累计过程线偏离天然径流过程线最为严重，地下水补给量及泉水溢出水量也具有类似衰变特征。上述水循环衰减的程度，与该流域中游区灌溉面积和引用水量增加密切相关。其中20世纪80～90年代人类活动对流域水循环衰变影响程度从50年代的19％增大至54％，远超过流域尺度水循环自然调节能力，其拐点为37％。

英文摘要：

On base of a great deal data from the investigation, it is expounded with studies of the integrative correlation that the natural characteristic of water circulation is lost in Heihe River Basin since 1980, which coefficient of deviation from mean is less than zero and is prick up in situation. The surface runoff changes the man -made state that is departure from nature state, annual the may is most severity in departure. Not only the runoff in the lower reaches is largely decreased, but also the recharge and the motion of the groundwater in the middle reaches loses the natural characteristic and the overflow of groundwater decreases continuously therefore the ecological environment of the lower reaches was retrogressed due to above variation. The debilities are closely correlation with the increase of infield area and consume water quantity in the middle reaches of Heihe River Basin. The human influence rate since 1980 is up to 54% from 19% in 1950s,which is far greater than nature bearing capacity. The natural charac- teristic of surface runoff changes the man - made state after the human influence rate is greater than 37% in the middle reaches of the Heihe river basin, the Northwest internal region. Not only the runoff in the lower reaches is largely decreased, but also the recharge and the motion of the groundwater in the middle reaches loses the natural characteristic and the overflow of groundwater decreases continuously the ecological environment of the lower rea- ches was retrogressed due to above variation. The climatic and human activity impacts importantly on groundwater recharge variation in the middle reaches of Heihe River Basin of the Northwest internal region, the influence intensi- ty of the human activity to groundwater recharge is 85% in middle reaches, which happen mainly in the stage of spring irrigation. Therefore, the key hand to realize groundwater resources sustainable utilization and the ecological environment protection in lower reaches is to adjust to human activity in rules that is in