天山山前典型流域水循环研究

天山 降水 同位素 水循环 地下水库
庞忠和 2007-01 项目
【英文摘要】Taking the Tianshan,Tarim basin in Xinjiang as a case, the project investigated the impacts of climate change and anthropogenic activities on the evolution of the water cycle and adaptation measures.Key results include: (1) Successive and high-frequency precipitation sampling of eastern Tianshan shows that three processes (air mass adiabatic expansion, convective precipitation and evaporation) control the evolution of precipitation isotopes. (2) In the last 40 years, the river runoff has increased by 10% since 1996. A modified model-HySis for hydrograph separation by using an integrated non-linear inequalitiy equations and multi-endmember mixing as as a water balance constrained by hydrological and water chemistry data. A case study of Urumqi catchment, eastern Tianshan, shows that the inputs to the total runoff from precipitation, snow and ice melt and groundwater are 56-64%,5% and 31-39%, respectively. (3) Based on piedmont water cycle studies, groundwater reservoir-modernized Karez is proposed to increase flood water use and groundwater storage. The construction of groundwater reservoir near G314 National Highway would accelerate the rate of groundwater circulation upper stream and enhance infiltration from floods to groundwater, which can then be used for irrigation. (4) Study on the relation between groundwater recharge and vegetation in the middle Tarim River shows that the modern recharge is limited and is crucial for growth of vegetation. The construction of embankment on the Tarim River appears to have reduced groundwater recharge, causing the water table to drop and ecosystem to degenerate.The results are relevant to prediction, sustainable use of water resources and ecosystem protection.
【中文摘要】本项目以新疆干旱区天山和塔里木盆地为例,进行了气候变化及人类活动对山-盆水循环演化与适应途径的研究,取得了以下主要成果。(1)对天山子系统降水同位素高密度逐次采样得出云层内的"气团绝热膨胀"、"对流降水"和"蒸发作用"三种过程控制着降水同位素的演化。(2)在过去的40年中,塔里木盆地出山径流量1996年后增加了10%。提出利用非线性不等式组将多元混合模型和水量平衡模型整合在一起,以水文观测数据和同位素数据作为约束条件的HySis径流同位素分割模型;以东天山乌鲁木齐河为例得出各补给成分的比例分别为:降水占56-64%、冰雪融水占5%、地下水占31-39%。(3)基于山前水循环的研究,提出了采用地下水库-现代坎儿井提高山前洪水利用效率和调蓄能力,指出在台兰河G314国道附近修建地下水库,将加速上游地下水循环,有助于洪水拦截入渗到地下,再通过地下水库调节后进入地表渠道进行灌溉。(4)研究了塔里木河中游河岸地下水补给属性及与生态关系,发现补给范围十分有限,并与植被生长状况关系密切,可能受堤防影响,对胡杨林的保护不利。结果对于预测水资源变化和可持续利用及生态保护具有理论和实际意义。