三峡库区东河河流等级及生态结构分析

Analysis on River Hierarchy and Ecological Structure of Donghe River in Three Gorges Reservoir Area

利用GIS技术进行河流等级结构划分,研究了三峡库区东河流域河流的等级体系。将整个东河流域河溪分为6级,并在此基础上研究了不同等级河溪与海拔高程和坡度的关系。研究发现,河溪在由低等级向高等级变化时,其空间分布范围逐渐由坡度大、海拔高向坡度小、低海拔的平缓地带过渡;低等级溪流周围植被生长状况好于高等级溪流周围植被。东河1、2级河流生态结构的完整性主要受自然干扰影响。3、4级河流水体落差大,水能丰富,河流主要受小水电影响;建议充分考虑河流生态需水,维护河流生境的连通性,保证水坝下游河段的河流生态健康。5、6级河流沿岸人为活动强度较大,水质较差;建议对河岸植被进行改造和重建,提高河岸植被的多样性和群落结构层次,减缓面源污染对河流健康的影响。对受三峡水库水位的波动影响的河段,建议实施生态恢复工程,改善生态环境质量。

Stream hierarchy of Dong be River was analyed by using GIS technology.The total watershed of Dong he River was divided into six grades.Relationship between river grade and elevation and slope was researched.The result indicated that river with higher grade distributed in those areas with smaller slope and lower elevation.Vegetation in watershed of lower grade stream is better than that in watershed of higher grade.The first and second grade streams were influenced by natural disturbance and maintained high quality of ecosystem integrality.The third and fourth grade rivers with high water slope and rich hydropower potential were significantly influenced by small hydropower.Ecological water demand of the reach in the downstream of dam should be released in order to maintain habitat connexity and river health.The fifth and sixth grade rivers were influenced by intensive anthropogenic disturbance with poor water quality.Riparian vegetation with high diversity and multi layers should be reestablished in this area to decrease non-point source pollution.Ecological engineering should be carryied out in reach influenced which was by the fluctuation of the Three Gorges Reservoir in order to improve its landscape quality.