汾河水源区典型小流域不同景观带水文过程研究

At present, there is less research on the integrated hydrological processes in river headwater catchment, and the influences of frozen soil, snow, groundwater, surface water and precipitation on the mountain runoff are also very fuzzy. Fenhe river basin, as a unique "coexistence system of water and coal", is in the fragile ecology region with mining. Therefore, the research on its hydrological processes in different landscape zones still is the key scientific problem that need to be solved. Based on Fenhe river basin hydrological experimental research station, with the combination of field investigation sampling, experimental observation and laboratory analysis, this research project applied isotopic technique, hydrochemical tracers, landscape pattern principle and "3S" technology, and took various water body,vegetation and soil in the subalpine meadow zone, subalpine shrub zone, medium high mountain forest zone, sparse forest and shrub zone and mountain grassland zone in the typical basin of Fenhe river headwater catchment as the research subjects. The objectives of this research project are to bring the seasonal frozen soil, snow cover, groundwater, surface water and precipitation into an integrated hydrological cycle system, and to identify the temporal and spatial changes in runoff contributions. In addition, it aims to probe into the hydrological processes in different landscape zones, to illustrate the mutual responses and feedbacks between hydrological processes and ecosystem in each of the landscape zones. It can provide a scientific basis for ecological construction, management of water resources and the improvement of water benefit on each scale, and also can enrich the foundation theory of eco-hydrological research.

目前流域水源区完整水文过程规律研究还非常薄弱，冻土、积雪、地下水、地表水和降雨等水体对出山径流贡献的认识还很模糊。山西汾河流域具有独特的"水煤共存系统"，为生态脆弱矿区，对其不同景观带水文过程的研究仍是尚待解决的关键科学问题。本项目拟依托汾河水文试验研究站，采用野外调查取样、观测试验和实验室分析相结合的研究手段，应用同位素技术、"3S"技术、水土化学分析与景观格局分析等方法，以汾河水源区典型小流域亚高山草甸带、亚高山灌丛带、中高山森林带、疏林灌丛带和山地草原等的各种水体、植被和土壤为研究对象，将季节性冻土、积雪、地下水、地表水和降雨等纳入完整水文系统，揭示其对出山径流贡献的时空变化规律，解析不同景观带水文过程机理，阐明各景观带水文过程与生态系统相互响应与反馈机制，为解决流域生态建设、水资源管理和提高各尺度水效益等问题提供科学依据与参考，也将丰富生态水文等方面研究的基础理论。

目前流域水源区水文过程规律研究还较薄弱，对出山径流贡献的认识还较模糊。本项目针对山西水环境恶化、水资源供需矛盾异常尖锐的现状，衔接山西迫切需要解决的水问题。采用野外调查取样、观测试验和实验室分析相结合的研究手段，应用同位素技术、“3S”技术、水土化学分析与景观格局分析等方法，以汾河水源区典型小流域亚高山草甸带、亚高山灌丛带、中高山森林带、疏林灌丛带和山地草原等的各种水体、植被和土壤为研究对象，将季节性冻土、积雪、地下水、地表水和降雨等纳入完整水文系统，解析其对出山径流的贡献，并对不同景观带表土沉积粒度和地球化学元素进行研究，揭示不同景观带水文过程机理。结果表明：汾河水源区亚高山草甸带与中高山森林带是汾河源区主要径流形成区，疏林灌丛带与山地草原带在时空上滞后了雨季降水的汇集。源区径流主要由降雨、地下水、积雪和冻土融水混合补给。流域内降水很少直接产生地表径流补给河流，而是经过各景观带下渗，转换成壤中流、孔/裂隙水或地下径流，最终汇入河道，完成“补径排”水文循环过程。研究结果表明汾河源区表土沉积物以粉砂为主，辅以一定数量的极细砂和粘土，细砂和中粗砂含量较低；总体上沉积物分选差，呈正偏和极正偏的分布；风成沉积和河流沉积并存，与该区河流发育有着密切的关系。表土沉积以SiO2、Al2O3、Fe2O3为主，Ca和Mg等活动性元素随海拔高度影响的降水变化呈现明显的垂直差异，表土沉积物的发生发展可能与中国黄土物质的组成具有一定的同源性。研究成果为解决流域生态建设、水资源管理和提高各尺度水效益等问题提供科学依据与参考，也丰富生态水文等方面研究的基础理论。