水利生态投资项目外部效益评价研究

水利生态投资项目是为了改善生态环境的投资行为，这种项目的效益评价不仅要考察内部效应而且应该考虑项目的外部效益，否则将失去评价结果的客观与公平性。文中建立了水利生态投资项目外部效益的评价指标体系及评价方法，提出用综合效益水平指数反映其外部效益水平，具有可操作性。基于外部效益具有的滞后性，建议对水利生态投资项目的评价采取即时评价与长期评价相结合的方法，保证评价结论的科学与完整。

Research on external benefit evaluation of ecological investment for water conservancy

The ecological investment project for water conservancy is an investment activity for improving the entironment con-cerned, for which not only the internal benefit has to be evaluated, but also the external one; otherwise, the evaluation result will not be objective and equitable anyhow. An index system with the evaluation method for the external benefit evaluation of the e-cological investment for water conservancy is established herein, in which an operable integrated benefit index for reflecting the level of the external benefit is put forward. In light of the hysteresis of the external benefit, a method of combining the timing e-valuation with the long-term one is suggested furthermore to ensure that the evaluation conclusion is to be integrated and scien-tific.