石羊河上游宁缠河小流域径流组分构成及汇流过程研究

Shiayang River upstream is located in the eastern of Qilian Mountain. It is the junction region of the monsoon and non-monsoon area, as well as the arid and semi-arid area. There are vary on the underlying surface. The water resource at the upstream has significant impact on the production and living as well as the ecologic environment in the middle and downstream area. We selected the upstream of Shiyang river as the study area, melt water, precipitation, runoff and groundwater were collected and analyzed based on the methods of runoff separation (Three water runoff separation model) and typical solute tracer(Si, DOC). The following work has to be done: (1) To study the stable isotopic and typical solute tracer characteristic in different water bodies, and to reveal the temporal and spatial variation patterns of stable isotopes and typical solute tracer. (2) To analyze the origin and dynamic change of the mixture runoff. (3) To identify the impact mechanism of the difference among hydrological underlying surface at the different landscape on runoff processes. Especially the types of frozen soil in the confluence area were analyzed, and the influence of the frozen soil melting on the rainfall runoff process. The project can make contributions to improve the knowledge of the effects of the complex climate system on temporal and spatial variation of the runoff supply, to provide a physical basis for the development and improvement of distributed hydrological model and provide scientific basis for the rational use of water resources and protection of ecosystem in the arid oasis area.

位于祁连山东段的石羊河上游，是季风与非季风、干旱与半干旱交界区，气候系统复杂，下垫面介质多样，上游水资源形势对中下游生产生活和生态环境影响剧烈。研究拟以石羊河上游宁缠河流域为研究对象，收集流域内冰雪融水、大气降水、径流和地下水样品，通过实验分析，以径流分割（基于稳定同位素和可溶性离子的三水源径流分割模型）和典型溶质(溶解硅：Si；溶解有机碳：DOC)示踪为基本研究手段，开展如下工作：(1)探寻不同水体稳定同位素和化学示踪剂时空分布规律及动态变化过程；(2)分析混合径流的来源及动态变化；(3)识别降雨在汇流过程流经的路径及沿途发生的迁移转化过程，尤其注重分析降水汇流区的冻土类型和冻土消融过程对降雨径流过程的影响。研究有助于提高对复杂气候系统作用高寒流域径流补给和汇流过程的认识程度，可为开发和改进分布式水文模型汇流和融冰(雪)模块提供物理依据，也可为下游绿洲区水资源管制和合理利用提供科学依据。

祁连山东段石羊河上游处于我国季风与非季风区、干旱与半干旱区的分界线附近，1960年以来，流域内冰川面积减少了20%以上，发源于此的石羊河出山径流量整体变率较大。出山径流量减少引发了诸如中下游绿洲萎缩、土壤沙化、地下水超采等严重的生态问题。随后关于石羊河流域中下游径流变化及用水管制的研究逐步开展并取得了丰硕成果，但是由于山区径流补给和汇流机制研究不足，导致对于出山径流减少缺乏大家公认的解释，进而增加了流域生态、环境和社会经济效应等相关研究的不确定性。传统水文学方法不能很好的解决石羊河上游径流补给和汇流过程时空变化的问题。.本研究在石羊河上游宁缠河流域建立定位监测系统，综合气象、水文、同位素和水化学多源数据资料分析了石羊河上游宁缠河小流域径流组分构成及汇流过程。厘清了宁缠河流域不同季节不同水体稳定同位素和水化学特征的变化规律，探明各种补给来源对河道径流贡献比例的变化规律及其原因和机制，进一步明确宁缠河流域降水汇流路径和冻土对汇流机制的影响。.基于本项目，项目组向甘肃省水利厅、甘肃省农业资源区划办公室提了交河源区积雪量偏少预警监测报告一份，发表学术论文31篇，其中SCI收录论文22，CSCD收录论文9篇，获批专利15项，获批软件著作权2项，公开发布数据集3个，培养研究生6名。在项目支持下建成西北师范大学石羊河流域生态环境观测研究站河源区观测系统。研究明确了季风边界高寒山区径流形成过程和机制，为基于物理过程的高山寒区分布式水文模型模拟研究提供理论基础，提升对石羊河流域水资源形成及其转化规律的认知水平。

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