Mekong at the Crossroads: Next Steps for Impact Assessment of Large Dams

The Mekong River in Southeast Asia stands at the crossroads. As discussed in Ambio Special Issue (Kummu et al. 2008), the crossroads is ultimately about the way the river and its abundant resources should be used, with the most heated debate evolving around the issue of large hydropower dams. A relatively pristine river with an estimated hydropower potential of 53 000 MW in the basin, the Mekong forms a tempting source of energy for the growing riparian economies (ICEM 2010; Grumbine and Xu 2011). Yet, the dams are estimated to radically reduce the current benefits derived from the river, including its multibillion dollar fisheries that form the basis for food security and livelihoods for millions of people (Kummu and Sarkkula 2008; Lamberts and Koponen 2008; Dugan et al. 2010; Arthur and Friend 2011). The thematic crossroads thus appears largely as a choice between large-scale, economic-driven water utilization and a more diverse, decentralized use of water-related resources (Keskinen 2008; Kummu et al. 2008; Molle et al. 2009; Lazarus et al. 2011; Stone 2011). We argue that there is also another, methodological crossroads that deals with the most suitable ways to assess the development plans. While this crossroads is much less discussed, the entire debate about the Mekong development revolves very much around such assessments, as their findings are used to justify the development plans. The contradictions regarding the assessments became well visible last April, when the four member countries of the regional Mekong River Commission (MRC) failed to reach a consensus on the first mainstream dam proposed by a MRC member country, namely the Xayaburi dam in Laos (MRC 2011a). Laos insists that the planning of the project is sound and the dam construction can start, followed by a number of other mainstream dams. Other MRC countries of Cambodia, Thailand, and Vietnam are, however, concerned about harmful impacts, and call for more rigorous assessments—Vietnam even suggested a 10-year suspension of all mainstream dam plans to allow enough time for this. As a result, during the MRC Council Meeting in December 2011, the ministers from the four MRC countries agreed that a further study about the impacts of the mainstream hydropower projects is needed (MRC 2011b). The suggested strengthening of the regional assessment processes has a good chance to become a landmark event even beyond the Mekong, and it can make the Mekong countries the forerunners in cumulative assessment of hydropower dams and other large-scale water development. For after a slowdown in the construction of large dams at the turn of the millennium due to their remarkable environmental and social costs (WCD 2000), recent years have witnessed a renewed interest toward hydropower (Moore et al. 2010). This has been partly thanks to improved planning and assessment processes, but first and foremost due to rapidly increasing energy demand particularly in the developing world. In the Mekong, the combination of high dependency on hydrocarbons and rapid increase in electricity demand—around 8 % per year, one of the highest in the world—has led to a renewed push toward large-scale hydropower (ICEM 2010). Well over hundred large dams are planned to the mainstream and the tributaries (MRC 2010; Fig. 1), making the Mekong the scene for one of the most intensive hydropower developments globally. Fig. 1 Existing and planned dams in the Mekong River Basin, with mainstream dams marked with boxes and tributary dams with circles (modified from Johnston and Kummu 2012) Assessing the Impacts of Water Development The Mekong has seen a number of regional impact assessment processes of planned hydropower dams and other water development, many of them done by the MRC (Table 1). However, as China is not a member of the MRC, the current regional assessments are focused on the Lower Mekong Basin, and the Chinese hydropower projects are largely seen just as upstream drivers of change. In sum, all major assessments indicate remarkable economic benefits from hydropower, but also significant negative impacts, particularly to the immense fish production of the river. The benefits and costs of the planned dams are also estimated to be unevenly distributed, both within and between the riparian countries. At the same time, the estimates about the magnitude and actual implications of the impacts range widely, thanks largely to differing methods and framings used in the assessments. Table 1 Selected regional assessment processes related to the Mekong’s development plans When comparing the findings of the different assessments, it is interesting to note that the assessment done directly within the MRC (2006, 2010) seem to have bit different approach than the assessments done more independently (MRCS/WUP-FIN 2007; ICEM 2010). Most remarkably, the MRC assessments tend to downplay the uncertainties related to assessment processes and instead put more emphasis on the controllability of the impacts and the manageability of the identified trade-offs (Kakonen and Hirsch 2009). We suggest that these characteristics may have to do with the dual role that the MRC has, as it seeks to act both as an independent knowledge producer and as a political discussion forum between its member countries. While such dual role is understandable and globally rather common, the problem is that it has resulted in unhealthy practices, and for example, assessment results are commonly subjugated to the political screening by the MRC member states before being published. The situation is, however, changing. Following the consultation process of the Xayaburi hydropower dam, also the riparian countries are now calling for broader assessments, and increasingly question the discrepancies between the assessments. There thus seems to be an obvious need to critically review and partially revise the existing assessments methods, in order to make them more responsive to the needs of regional and national decision making. Building on the review of different assessments presented in Table 1 (see also Keskinen 2008; Sarkkula et al. 2007; Keskinen and Kummu 2010; Keskinen et al. 2012), we argue that the most critical steps in revising the Mekong impact assessment are the following three transformations: from assessments of individual projects and sectors to cumulative impact assessment; from purely technical approaches to more holistic and inclusive analyses; and from separate studies to parallel, comparative assessments that also clearly spell out the uncertainties and risks included. Cumulative Assessment Current impact assessments in the Mekong tend to have a strongly sectoral approach, assessing the impacts of proposed water development separately to water flows, fisheries, livelihoods and economy (see e.g., MRC 2006, 2010). While such an approach provides a logical starting point, it also compartmentalizes the river system into separate units, which are then connected mainly through rigid causal chains. As the river basin in reality forms an interconnected system with complex impact and feedback loops, such compartmentalization leads easily to oversimplified representation of the actual net impacts (Keskinen 2008; Lamberts 2008). The assessments also focus predominantly on hydrological impacts, as these are by far the easiest to estimate. Yet, the debate about the dams is not only about the changes they cause in water levels, but essentially about the impacts to water-related ecosystems and, consequently, to livelihoods and food security. None of the current assessments in the Mekong is, however, able to describe such impacts in a very reliable manner. In addition, most impact assessments focus on project level, looking at the estimated impacts of a certain predefined set of development plans. Yet, in the context of several dozens of water infrastructure projects in both the Mekong mainstream and the tributaries, such separate assessments cover only part of the actual, combined impacts of the planned water development projects. For these reasons, it feels evident that project level, sectoral assessments should be complemented with broader, cumulative assessments looking at the combined impacts of all known development plans that better account for social and economic impacts. Critical is also the temporal dimension of the expected impacts: as the development projects are not implemented simultaneously, also their impacts are felt differently at different time scales.