Sustainable Hydropower Development in the Mekong River Basin Guy Ziv Ecology and Evolutionary Biology Princeton University Eric Baran WorldFish Center Cambodia So Nam Cambodian Fisheries Administration Ignacio Rodriguez- Iturbe Civil and Environmental Engineering Princeton University Simon A. Levin Ecology and Evolutionary Biology Princeton University PNAS 109 (15): (April 10, 2012) Lead Scientist Natural Capital Project Stanford University

How Much Freshwater Exists? From: Only 2.7% of the water on Earth is freshwater (<500 parts per million of dissolved salts)

Most of Humanity lives near Freshwater Bodies Kummu M, de Moel H, Ward PJ, Varis O (2011) How Close Do We Live to Water? A Global Analysis of Population Distance to Freshwater Bodies. PLoS ONE 6(6): e20578 (2011)

Ecosystem Services of Freshwater Rivers and Lakes Fish (and other food) Recreation Navigation/Transport Soil Regeneration Irrigation Hydropower Sanitation/Waste Disposal Trade -Offs

The Mekong River Basin 12 th largest river in the world Flows through 6 nations 60 million people, mostly poor Fish is a major part of diet Annual catch 2.1 million tonne – 15% of global freshwater catch The 2 nd most biodiverse river in the world (after Amazon river) 795,000 km 2 4,600 km 795,000 km 2 4,600 km

Basin Development Plan 2 (BDP2) Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030) 16 dams 1 dam

Basin Development Plan 2 (BDP2) 40 dams 7 MS dams Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030)

Basin Development Plan 2 (BDP2) 70 dams 7 MS dams Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030)

Basin Development Plan 2 (BDP2) 70 dams 7 MS dams Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030) 6 MS dams

Basin Development Plan 2 (BDP2) 70 dams 7 MS dams Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030) 9 MS dams

Basin Development Plan 2 (BDP2) 70 dams 7 MS dams Established in 1995, the Mekong River Commission coordinates between Laos, Thailand, Cambodia and Vietnam BDP2 Scenarios: – Baseline (2000) – Definite Future (2015) – No Mainstream Dams (2030) – 6 MS Dams in upper LMB (2030) – No Cambodia MS Dams (2030) – All 11 MS Dams (2030) 11 MS dams

Strategic Environmental Assessment (SEA) released October 2010 Reports mainstem hydropower impacts on economy, hydrology, society and fisheries Recommended to postpone decision for 10 years for further studies Cumulative Impact Assessment of tributary dams impacts is highly needed Grumbine et al, Science 332, 178 (2011)

Fish guilds in the Mekong Migration Lateral None Migratory species Longitudinal

Research Questions What are the source areas for migratory species population? How will different hydropower development scenario impact the fish biodiversity of the Mekong river? What impacts will these dams have on fish productivity (tonne fish catch/year), and what human population will be impacted?

Model for Fish Migration “River” part – seasonally varying carrying capacity, resource limitation in both seasons. “Lake” part – carrying capacity during wet season far exceeds dry season, density-independent growth in wet season Resident species take up freed resources, possibly no net loss in productivity No juveniles/larva migrating downstream – diminished productivity Obligatory migration

SeasonalityBase Flow Migration Effectiveness REF: Costa-Cabral et al. Hydrological Processes 22, (2008) The 3S contributes most to total habitat (per unit area) 3S region

sources 877 -Presence/absence data for 877 fish species migratory species Species Habitat

BDP2 ScenarioYear Number of Tributary Dams in LMB Number of Mainstrea m Dams in LMB Δ Total Hydropower Generation [TWh/yr] Δ Migratory Fish Biomass [%] Biodiversity Risks: number of species… vulnerableendangered critically endangered Baseline Definite Future No Mainstream Dams Mainstream Dams on upper LMB No Cambodian Mainstream Dams All 11 Mainstream Dams Definite Future + 6 Mainstream Dams on upper LMB

0.3% per TWh/yr 1.3% per TWh/yr (Se Kong dams) 4% per TWh/yr (LSS2 dam) Each gray dot is one damming scenario (2 27 in total) The same energy production can be achieved with very different environmental impacts Pareto-Efficient scenarios show strong non-linear trade-offs between energy and productivity

Provisioning Service (market value) Supporting Service (unclear value)

Conclusions & Perspective Hydropower, biomass and conservation have a strong non-linear trade-off The major beneficiary for hydropower is Lao PDR whereas for fish it is Cambodia and Vietnam Hydropower development will cause inequity, where winners (Loa PDR) ≠ lossers Some dams can and should be avoided, including LSS2 whose construction is planned by the end of 2012

Acknowledgments David Tilman, Pamela Matson, Jianguo Wu for their comments Inland Fisheries Research and Development Institute (IFReDI) for fisheries data Funding: – James S. McDonnell Foundation (G.Z., I.R.I.) – AXA Research Fund (G.Z.) – MITSUI Bussan and the Government of Japan (Japan Mekong Fund) (E.B.)

½ of all species use less than 70% while the other ½ use % ½ of all species use less than 70% while the other ½ use % Nearly 60% of total habitat may be blocked by 2030!

When does (fish) migration occur? Reproduction Downstream migration Growth Competition Upstream migration Lake River Wet Season Deterministic dynamical model: for Non- migratory Migratory Steady state: Evolutionary Stable Strategy: largest possible Seasonality (abiotic) = K w /K d Migration Effectiveness (biotic) Inter- changable Carrying capacity upstream is K d at the dry season, and K w at the wet season. Species may become extinct if over-exploited! All species will have the same e within each locality

e(x) Fraction of white fish: x = 1-κ/e no white species, i.e. κ>e κ – seasonality, variability of upstream carrying capacity (= accessible area x runoff production) e – migration effectiveness, number of returning offspring AMCF survey (mainstream – filled, tributary – open) sub-basins with white species, i.e. κ<e