下垫面条件对流域极端事件影响及综合应对框架

The Impact of Underlying Surface Changes on the Extreme Hydrological Events and the Comprehensive Countermeasure Framework

在剖析下垫面条件变化对流域极端水文事件演变影响的基础上,构建了流域极端水文事件综合应对技术框架,并阐述其中的关键研究命题。结果表明,自然植被条件能够提高流域干旱之前土壤含水量并降低干旱过程中土壤蒸发速率,在一定程度上起到减缓干旱的强度和持续时间的作用;水利工程通过调节流域水资源的时空分布,增加可利用水资源量,能够缓解甚至规避流域干旱事件,但同时可能加剧坝址下游地区的干旱程度。自然植被条件将延长降水坡面产-汇流历时、降低洪峰流量,对极端降水洪涝事件具有一定的消减作用;此外,流域水土保持和修建水利工程等下垫面条件改变有利于河道行洪过程,能够起到缓解洪涝事件的作用。基于下垫面条件变化的流域极端水文事件综合应对技术框架包括旱涝事件监测、机理识别、影响评价和综合应对四个方面的内容,其中的关键研究命题主要为下垫面条件变化对流域极端水文事件影响的定量评估、面向流域极端水文事件合理的水土资源配置及其集成管理等。

Based on the influencing mechanism analysis of the underlying surface changes on the extreme hydrological events,the comprehensive countermeasure framework against the extreme hydrological events has been installed,and the key topics of the research work are proposed accordingly. The results showed that： vegetation could mitigate droughts by increasing soil moisture and reducing soil evaporation; while hydrological projects, which could increase the water resources quantity by changed the temporal and spatial distribution,could mitigate droughts in the water supply areas,but likely aggravate the droughts in the water loss areas. In addition,vegetation could also prolong the runoff generating time and lower peak flow,which can mitigate floods. The underlying surface change,such as the soil and water conservation and the hydrological projects,benefits the flood draining. The comprehensive countermeasure framework against droughts and floods based on the underlying surface changes includes droughts and floods monitoring,mechanism recognition,impact assessment and comprehensive countermeasure. The key topics of the research work mainly includes the quantitative evaluation of the underlying surface changes on the droughts and floods,and the appropriate allocation and integrated management of the water and soil resource against the droughts and floods.