Dams can produce electricity and ensure water security, but at the same time they radically alter the hydrological regime of rivers with significant consequences for the economic and environmental welfare of the region in which they are located. Cost-benefit analysis (CBA) is currently the most frequently used framework for the economic evaluations of dams. Changes at different time scales influence the economic appraisal of dams. However, change and adaptation at both the operational and the structural level are often not included in the CBA evaluation. Not including change and adaptation limits the realistic estimation of cost and benefits, and the appreciation of resilient solutions that offer satisfactory responses for a large set of future scenarios.

In this paper we consider the specific features of large dams in an African context, and identify methods for an economic evaluation that takes into account for change and adaptation at both the operational and the structural scales, as well as their interplay. These methods are then applied to the ex-ante evaluation of a system of existing dams on the Senegal River Valley. Results indicate the economic potential of the dams under changing conditions, for both adaptive and non-adaptive reservoir operation strategies.

大坝可以发电并确保水的安全，但同时它们从根本上改变了河流的水文状况，对它们所在地区的经济和环境福利产生了重大影响。成本效益分析（CBA）是目前用于大坝经济评估的最常用框架。不同时间尺度上的变化会影响大坝的经济评估。但是，CBA评估通常不包括运营和结构方面的变化和适应。不包括变更和适应，限制了对成本和收益的实际估计，也限制了对在未来很多情况下都能提供令人满意的响应的弹性解决方案的赞赏。

在本文中，我们考虑了非洲背景下大型水坝的具体特征，并确定了一种经济评估方法，该方法考虑了运营和结构规模上的变化和适应，以及它们之间的相互作用。然后将这些方法应用于塞内加尔河谷现有大坝系统的事前评估。结果表明，对于自适应和非自适应水库运行策略，大坝在变化条件下的经济潜力。