Discussion of results

The table below shows the results from the CBA. The results are indicative due to the assumptions being made, but some conclusions can be drawn from them. Firstly, both at the site level and at the basin level flood-based agriculture is economically viable. Over the lifetime of the project, the net present values (NPV) are positive, while the benefit-cost ratios (BCR) are above 1. The internal rates of return (IRR) of 30.2% and 8.7% show that there is a high return on investment.

Secondly, at the site level, it turns out that there is only one tangible benefit – ecotourism revenues. The change in the agricultural model does – under the present assumptions – not generate any tangible economic benefits at the site scale or basin scale, though there are intangible benefits, such as health benefits and non-use benefits. At the basin scale, the benefits of fisheries are about 86% of the total benefits. Without benefits for fisheries, the project would not be viable as the benefits from ecotourism and reduced flood risk would not be able to cover the costs of the project. However, considering the potential of a severe decline in agricultural productivity and output over the long run due to the lack of seasonal flooding, leading to soils sinking below sea levels and reducing fertility, even without the benefits of fisheries the project could be viable beyond the current project horizon.

Thirdly, the study of Do and Bennett (2007, see footnote 6) shows that there are considerable non-use values, which could already cover the costs of several projects. Non-use values are, however, intangible and would not contribute to the funding of the project. 

_{Table. Results of the CBA for flood-based agri- and aqua-culture, Present USD values at 6% discount rate over a 50 year project lifetime.}