基于能值分析的大坝生态效应评价——以尼尔基大坝为例

能值分析可提供客观真实的统一量化平台,在自然、经济系统整合分析方面具有显著优越性.将能值分析方法引入大坝生态效应评价,提出基于能值分析的大坝生态效应评价概念框架,绘制库区生态系统能值流图,构建包括生态系统运行效率、生态系统组织结构、生态系统功能维持和生态系统环境安全4方面共9个指标的能值综合评价指标体系.对尼尔基大坝建设前后库区生态系统变化进行对比性评价,结果表明,生态系统的运行效率、功能维持能力有较大提升,组织结构出现不平衡,环境负荷较高,可持续发展能力受损,需减少因流域水土流失与塌岸导致的库区泥沙淤积,以控制不可更新资源能值输入.

Emergy-based assessment of ecological effects of dams:a case study of the Nierji Dam

Emergy analysis may provide an objective and unified metric with significant advantages in integrated analyses of natural and economic systems. Emergy analysis is introduced in this paper to assess the ecological effects of dams. First,we establish a conceptual framework for the assessment based on emergy,delineate an emergy flow diagram of a reservoir ecosystem,and propose an emergy-based comprehensive assessment index system which includes 9 indices categorized into 4 groups,i.e.,ecosystem efficiency,ecosystem organization structure,ecosystem service function and ecosystem environmental safety. Then,the changes of the Nierji reservoir ecosystem before and after the dam construction are evaluated. The results show that the ecosystem efficiency and service function maintenance ability have improved greatly,whereas the reservoir ecosystem suffers from the degradation of the balance of its structure,the increase of pollution load,and the reduction of its sustainable development capacity. Thus,it is necessary to control non-renewable resource inputs by reducing the reservoir's sedimentation caused by soil erosion and bank collapse.