Benefits

At the project site, fish catches have reportedly declined because of invasive plants and water level declines. The average income from fishing is about USD 12 per household per day for 4 kg per day. The catch in Goot Ting wetland is around 24,000 kg per year, hence the revenue is about USD 72,000 per year. On a local scale, implementation of the project might increase fish catches by 5% to 10%, which would mean a 5% to 10% increase in revenues from fisheries assuming prices remain the same. Taking the middle of the range, the benefits of the project would be USD 5,400 per year.

At the basin level, recent estimates indicate that the economic value of the Mekong fishery dropped by more than a third between 2015 and 2020^[1]. The estimated annual value of fish catch was estimated between USD 7.13 billion and USD 8.37 billion in 2019-2020.^[2] While it is difficult to estimate the impact of larger areas of flooded forests on fisheries income in the basin in the absence of quantitative data on the impact of wetland areas of fisheries, a rough indication is that if implementing the project in 25% of the highly suitable areas would only result in a 1% increase in fisheries, the revenues would already generate about USD 77.5 million in annual benefits if the middle of the range of the 2019-2020 estimated annual value of fish catch (7.75 billion) is taken as a base.

[1] Cowx IG, Lai TQ and So N (2024). Fisheries Yield Assessment by Habitat Type at The Landscape Scale in The Lower Mekong

River Basin 2020. Vientiane: Mekong River Commission Secretariat.

[2] Ibid

Invasive species can be used to make compost. Households can sell the compost or use it in their fields, which would reduce their production costs. As this would reduce the use of chemical fertilisers, it would also help to improve water quality.

Unfortunately, there is no quantitative information on the amount of compost produced by invasive species at the Goot Ting wetland or the basin scale, nor on the prices of such compost. Hence, it is not possible to include this in the calculation of the benefits. It is, however, expected that these benefits are relatively small.

Tourism at the Goot Ting wetland is currently limited to about 50 persons per year who come for bird watching. They stay on average two nights and spend about USD 30 per person. An ecotourism strategy, including building a simple visitor centre and developing information and promotion materials, could increase the number of visitors. Based on other ecotourism sites, the assumption was made that the project site could attract 1000 to 5000 (average 3,000) tourists per year, of which one-third would stay one night, one-third would stay two nights and one-third would just visit for the day. With wider accommodation and restaurant offerings, as well as boat rental and tours, it is assumed that a tourist staying one night would spend USD 20 (added value, excluding costs of the tourism offering), a tourist staying two nights would spend USD 40 and a day visitor would spend USD 15. Hence, the total annual benefits would be USD 75,000.

At the basin level, ecotourism cannot be implemented at all sites, as the total market demand for ecotourism is limited and not all sites are suitable, e.g., in terms of accessibility. In total, it is assumed that there would be 5 additional ecotourism sites throughout the basin, which each would generate USD 75,000 per year, hence in total USD 450,000 per year.

Through the creation and protection of habitat, the project could contribute to increased carbon sequestration. Increased carbon sequestration reduces greenhouse gases in the atmosphere, mitigating climate change, and hence benefiting people as a reduction in climate change and associated effects compared to a baseline without the project. This benefit can be valued through the amount of carbon sequestered by vegetation and a social price for carbon. Measuring this would require an estimate of carbon sequestration in the project area without and with the project. While wetlands sequester carbon, and the project potentially could increase carbon sequestration through sustainable wetland management practices, it is difficult to calculate the increase in carbon sequestration due to the project. Moreover, there are no established or accredited methods to assess carbon sequestration for floodplain wetlands, hence they are generally not considered for carbon credits. Compared to reforestation of flooded forests (NbS2), the climate change effects for wetland restoration are likely much smaller. As such, the reduction in climate change will not be quantified in the CBA.

By restoring hydrological connectivity between the rivers and wetlands at the basin level, the floodplain water storage capacity will increase. This could potentially lead to lower peak flood water levels and a reduction in flood damages and flood protection costs (e.g., lower requirements for levees). Moreover, there would be more water available in the dry season.

In terms of water storage, it is estimated that flood-based agriculture could store 220 million m³ of flood waters, leading to a flood depth reduction of 0.2 meters in the Mekong River, see Appendix A. However, assessing the quantitative impact of restoring hydrological connectivity on flood damage and flood protection is complex,^[1] hence only a very rough indication of the benefits can be given. The average annual cost of floods in the Lower Mekong Basin ranges between USD 60 to 70 million.^[2] Assuming the project would contribute to a 1% reduction in damages this would be USD 600,000 to 700,000 annually.

[1] See for instance Thanh, V. Q., Roelvink, D., Van Der Wegen, M., Reyns, J., Kernkamp, H., Van Vinh, G., & Linh, V. T. P. (2020). Flooding in the Mekong Delta: the impact of dyke systems on downstream hydrodynamics. Hydrology and Earth System Sciences, 24(1), 189-212 on the complexity of modelling and considerations to assess changes in the floodplain on flood levels.

[2] Mekong River Commission: https://www.mrcmekong.org/our-work/topics/flood-and-drought/

Non-use values are numerous and different for each person. Such values include bequest values (leaving something for the next generation), existence values (attaching value to knowing that something exists, for instance, expressed to donations to charity) and option values (not using it now, but maybe in the future). A monetary estimate of non-use values can generally only be obtained by asking people for their willingness to pay to conserve or enhance certain habitats, ecosystems or ecosystem services.

While there are some studies on the non-use values of wetlands in the Lower Mekong Basin, the results cannot be easily translated for use in the CBA in this study. For instance, Rakthai (2018) estimated the willingness to pay for biological diversity conservation in the Lower Mekong River Basin by households located along the Mekong River and found a value of USD 3.99 per household per year or a total value of USD 153,471 per year based on the population sample.^[1] This is, however, not specifically for wetlands and respondents gave their total value for biological diversity conservation, which may also include use values for some respondents. Hence, the non-use value cannot be quantified in the CBA.

The change in non-use values could be linked to the potential value of biodiversity credits. Biodiversity credits are a verifiable, quantifiable and tradeable financial instrument that rewards positive nature and biodiversity outcomes (e.g., species, ecosystems and natural habitats) through the creation and sale of either land or ocean-based biodiversity units over a fixed period.^[2] The market for biodiversity credits is, however, still at an early stage of development and the pricing of biodiversity credits is still largely unknown.

[1] Rakthai, S. (2018). Willingness to pay for biological diversity conservation of the Lower Mekong River Basin in Thailand: A contingent valuation study. Songklanakarin Journal of Science and Technology, 40(3), 570-576.

[2] World Economic Forum: https://initiatives.weforum.org/financing-for-nature/home

Surrounding the Goot Ting wetland, farmers grow rice, rubber trees and cassava and hold cattle. Farmers will need to shift to more sustainable agricultural practices – reducing the input of fertilisers and chemicals, stopping encroachment and limiting water pumping for irrigation – to conserve and restore the wetland. This may impact agricultural revenues. However, with proper outreach and training, the shift to more sustainable agricultural practices would not need to imply a reduction in agricultural revenues and could even increase agricultural revenues.

There is, however, not sufficient information to assess the impact of the project on agricultural revenue at the local or basin level. Hence, it is assumed that there is no impact on agricultural revenues (zero benefits / zero costs).

The table below provides a summary of the benefits.