Costs

The table below gives an overview of the cost estimates for the project site and basin. Note that these estimates are all very indicative and based on currently available data.

For the project, it is assumed that the investments costs are spread over two years at the beginning of the project period. Operational costs (items 1 and 10) are annual.

^{Table. Cost estimates and assumptions}

No.	Cost item	Estimate project site	Estimate basin
1	Protection and enhancement of river corridors	USD 400 / year	USD 82,900 / year
2	Installation of culverts	USD 0	USD 82,902,400
3	Creating / maintaining habitat connectivity	No costs, part of overall planning and management costs, see 7	No costs, part of overall planning and management costs, see 7
4	Installation or designation of buffer zones	No costs, part of overall planning and management costs, see 7	No costs, part of overall planning and management costs, see 7
5	Installation of natural pockets and / or biofilters	USD 2,500	USD 518,140
6	Studies, monitoring & analysis	USD 50,000	USD 10,362,800
7	Change of agricultural model	USD 200,000	USD 33,160,900
8	Initiating payment for ecosystem services to (former) landowners	N/A	N/A
9	Organized eco-tourism	USD 25,000	USD 125,000
10	Limiting activities / enforcement / community-based water management	USD 3,000 / year	USD 621,768 / year
	Total Capital Expenditure	USD 277,500	USD 127,069,300
	Total Operational Expenditure	USD 3,400 / year	USD 704,670 / year

Notes for the calculation of costs

Item 1: Costs for protection and enhancement of river corridors and canals that lead to the designated areas. For the main canals, it is assumed maintenance costs are similar to in the reference alternative, though operation and maintenance practices may change. For the smaller connecting canals, enhancement and maintenance (e.g., clearing vegetation, dredging, stabilising canal banks with plantings) along 10% of the length is assumed. The length of smaller canals in the project area is assumed to be 2 km. Cost is assumed to be 2 USD per metre (this is based on the cost of dredging, which is 2 USD/m³). Maintenance is an ongoing process, and it is assumed that it needs to be conducted annually. To arrive at a basin estimate, the costs on a local scale are multiplied by the increase in area (i.e., an area 10 times larger would cost 10 times more). In this case, the area for upscaling is about 200 times larger (103,628 ha) than the area assumed for the case study scale (500 ha).
Item 2: Installation of culverts or other water control structures to let the water in periodically and lower or remove embankments. Existing water control structures may be sufficient to manage flooding in the case study area as it is sufficiently low-lying. If the project is upscaled to the basin, more investments in water control structures may be needed in areas with less favourable conditions. A sluice gate under a dike would cost about USD 800,000 and annual operating and maintenance costs would be around USD 8,000 (1% of investment costs). At basin scale, it is assumed that one culvert per 1,000 ha is required.
Items 3 and 4: Creating habitat connectivity/corridors/buffers around existing assets. It is assumed that the acquisition of land is not needed. Planning and management of land use can achieve connectivity and corridors. This would involve planning, legislation (e.g., banning pesticide use), management costs (manpower), and costs to support farmers in implementing the measures. These costs are included as a one-time project cost under item 7.
Item 5: Installation of natural pockets and/or biofilters to enhance and improve water quality and groundwater replenishment. This would require some earthworks. It is assumed that per 1,000 ha, 0.25 ha or 2,500 m² needs to be deepened for USD 5,000, based on 1 m depth and earth moving costs of USD 2 per m³.
Item 6: Studies and monitoring costs: flood-based agriculture and NbS would require studies on water level fluctuations to understand flooding duration and frequencies, and monitoring and analysis of the effects on agriculture, biodiversity and sedimentation. To some extent, these costs would replace other costs of water management in the Mekong basin and would decline over time as more experience is gained with flood-based agriculture. An amount of USD 50,000 per project area of 500 ha is included as costs, and costs are scaled to the basin scale based on the proportional increase in area.
Item 7: The costs to transition to flood-based agriculture could include outreach and engagement costs to convince farmers to make the transition. Outreach and engagement costs can also aid in obtaining buy-in from suppliers and buyers in the value chain, training costs of farmers, and project management costs. These costs would entail additional manpower for governments, technical support costs, project management costs, project execution costs and training costs. Based on the project conducted by WWF, these costs are estimated to be USD 200,000 per project area of 500 ha. At the basin level, we assume that costs are 20% lower due to economies of scale.
Item 8: Setting up a system for payments for ecosystem services (carbon credits, biodiversity credits or other) requires a certain scale to cover fixed costs. These costs are currently unknown.
Item 9: The costs of building a simple visitor centre and developing an ecotourism strategy, brochures, etc. are estimated to be USD 25,000. Ecotourism could not 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 5 sites could have ecotourism, with a budget of USD 125,000 in total.
Item 10: It is assumed that enforcement costs would be USD 500 per month or USD 6,000 per year per 1,000 ha