Using the Freshwater Health Index to Assess Hydropower Development Scenarios in the Sesan, Srepok and Sekong River Basin

Abstract

Sustainable water resource management is a wicked problem, fraught with uncertainties, an indeterminate scope, and divergent social values and interests among stakeholders. To facilitate better management of Southeast Asia’s transboundary Sesan, Sekong and Srepok (3S) River basin, we used the Freshwater Health Index (FHI) to diagnose the basin’s current and likely future level of freshwater health. We used the conditions for December 2016 as a baseline, where Ecosystem Vitality and Ecosystem Services scored 66 and 80, respectively, out of a possible 100, whilst Governance & Stakeholders scored 43. Thus, the 3S provided a range of desired ecosystem services, but there were signs of environmental stress as well as undeveloped water governance systems and limited stakeholder engagement. We also modelled four hydropower development scenarios and found that increasing development reduced the scores of a subset of indicators. This compromised the future ability of the 3S basin’s ecosystem to provide its current range of services. The FHI helped identify data deficiencies, illuminated important social dynamics, made ecosystem–human–water dynamics more understandable to stakeholders, and examined the long-term dynamics of the basin.

Aligning the Freshwater Health Index Indicator System against the Transboundary Water Governance Framework of Southeast Asia’s Sesan, Srepok, and Sekong River Basin

“…The results of Souter et al [13] December 2016 FHI assessment (A summary of these findings is also available from the FHI website, http://www.freshwaterhealthindex.org/basin-reports.) found that, whilst the 3S basin's water ecosystem was showing signs of stress (with an Ecosystem Vitality score of 64), it provided a suite of desired ecosystem services (with an Ecosystem Services score of 80), but the water governance system was weak (with a Governance and Stakeholders score of 43).…”

“…found that, whilst the 3S basin's water ecosystem was showing signs of stress (with an Ecosystem Vitality score of 64), it provided a suite of desired ecosystem services (with an Ecosystem Services score of 80), but the water governance system was weak (with a Governance and Stakeholders score of 43). The work of Souter et al [13] also assessed a range of future hydropower scenarios, which predicted that, as the number of dams increased, Ecosystem Vitality and Ecosystem Service scores will decline.…”

“…Table 1. Freshwater Health Indicator components, major indicators and sub-indicators, their 3S basin score [13], and the number of laws, policies, and plans they align with, in each of the three countries. Water supply reliability relative to demand 95 0 1 2 2 Biomass for consumption 94 0 1 2 1 Regulation and support 66 Sediment regulation 39 0 0 1 1 Flood regulation 81 1 1 1 3 Deviation of water quality metrics from benchmarks 88 1 2 2 3 Exposure to water-associated diseases 67 1 1 1 2 Cultural/aesthetic 83 Conservation/cultural heritage sites 83 1 1 1 2 Recreation -Governance and Stakeholders 43 Enabling environment 42 Water resource management 50 5 3 2 3 Rights to resource use 45 5 1 1 2 Incentives and regulations 45 5 1 1 2 Financial capacity 42 5 0 0 2 Technical capacity 36 5 1 1 2 Note: FHI scores previously reported by Souter et al [13]; relevant laws, policies and plans are the subject of the present research.…”

“…None of the documents we reviewed provide specific details as to how to measure compliance, as neither minimum nor seasonal flows have been specified. The deviation from natural flow regime indicator can assist with this, and the score of 66 [13] for the 3S suggests that that the flow regime does not provide adequate flows to the Mekong River. The current flow regime also does not protect aquatic ecosystems, as the 3S' fish community has shifted from a specialist to generalist community [34].…”

“…However, simplification alone may not guarantee Srepok catchment may warm by 4 • C [18]. There are currently 66 operational dams in the 3S, eight more under contract or construction, and sites for another 37 have been identified [13]. Extensive dam construction in the 3S could increase dry season flows by 63%, whilst reducing wet season flows by 22% [19].…”