international conference watershed management mai · aquatic ecosystem connectivity, ecosystem...

Aquatic ecosystem connectivity, ecosystem processes,and watershed integrity under Mekong dam development

International Conference on Watershed ManagementChiang Mai

March 2011Nikolai Sindorf, WWF‐Conservation Science Program

Trang Dangthuy, WWF‐Greater Mekong Program Office

Methodology highlightsMethodology highlights

• develop a science‐backed environmental narrative that guides strategic decision‐making on dam impacts and connectivity, work towards a globally‐applicable template

• test river network connectivity visualizations on the Mekong with a focus on dam development

• propagate an ecosystem inclusive, basin‐wide, approach to dam development

©WWF, 2011

1. Aquatic ecosystem classification1. Aquatic ecosystem classification

2. Connectivity visualization2. Connectivity visualization

3. Dam locations3. Dam locations

4. Consistent connectivity metric4. Consistent connectivity metric

©WWF, 2011

ApproachApproach

•• captures relevant basincaptures relevant basin‐‐wide processeswide processes•• incorporates essential migration triggersincorporates essential migration triggers•• openopen‐‐sourced, transparent, replicable sourced, transparent, replicable

•• upstreamupstream‐‐downstream network analysisdownstream network analysis•• allows multiple scalesallows multiple scales•• globally replicable to any river systemglobally replicable to any river system

•• location based; not datalocation based; not data‐‐basedbased•• configuration of multiple dams, configuration of multiple dams, •• river system perspective river system perspective

•• network algorithm; no environmental valuationnetwork algorithm; no environmental valuation•• comparative and scalablecomparative and scalable•• not a silver bullet; part of much broader assessmentnot a silver bullet; part of much broader assessment

Elevation> 3,000 m> 100 m< 100 m

Classifier Association, representative of:

elevation temperature, climate, geography, plateau, upstream / downstream relations, ice / snow, delta / tidal influences

slope elevation drop in rivers, erosion / sediment rates, temperature, cascades / rapids, local runoff, vegetation

karsts chemistry, caves, endemism

river length

scale, seasonality, discharge, floodplains / wetlands, river‐landscape interaction

Slopeyesyesnono

KarstsRiver lengthmainstemmainstemtributarytributarystreamstream

++++++

©WWF, 2011Aquatic ecosystem classificationAquatic ecosystem classification

©WWF, 2011

Tonle Sap

Nam Chi

Nam MunSongkhram

Nam Loei

Nam Mae Ing

Nam Loi

Ngom QuZi Qu

Za Qi

YangbiQingshuilang Shah

Nam OuNam Tha

Nam Khan

Nam Ngum

Nam Cadinh

Se Kong

Se SanSre Pok

Se Bang Hien

Stung Sen

Siem Bok

Nam

es based

on FA

O datab

ase, 200

9, re

vised

Delta

Mekong connectivity schematicMekong connectivity schematic(duplicates removed)(duplicates removed)

Sekong, Sesan, SrepokSekong, Sesan, Srepok

Tonle SapTonle Sap

Nam Chi, Nam MunNam Chi, Nam Mun

DeltaDelta

Nam OuNam Ou

Nam NgumNam Ngum

©WWF, 2011

Connectivity applied to dams and large tributariesConnectivity applied to dams and large tributaries

Our dam databaseOur dam databasecontains over 50 ofcontains over 50 ofthe largest or mostthe largest or mostprominent dams in prominent dams in the basin, and the basin, and includes hydropower includes hydropower and agricultural dams,and agricultural dams,it excludes a largeit excludes a largeamount of smaller,amount of smaller,agricultural dams.agricultural dams.

©WWF, 2011


In our initial analysisIn our initial analysiswe found out thatwe found out thatthe current layoutthe current layoutof dams of dams ‘‘blocksblocks’’ 40 % 40 % of the Mekong. of the Mekong.

©WWF, 2011

Sekong

Sesan

Srepok

Nam Ngum

Nam Theun

Tonle SapTonle Sap

Nam Chi

Nam Mun

Songkhram

Nam Ou

Jinhhong

Sedone

©WWF, 2011

Sekong, Sesan, SrepokSekong, Sesan, Srepok

Tonle SapTonle Sap

Nam Chi, Nam MunNam Chi, Nam Mun

DeltaDelta

Nam OuNam Ou

Nam Theun Nam Theun Nam NgumNam Ngum

Mekong connectivity schematicMekong connectivity schematicDam locations (manual)Dam locations (manual)

©WWF, 2011


Number of connected ecosystems

1234611

©WWF, 2011

1313

1212

1111

1010

99

88

77

66

55

44

33

22

11

0 10 20 30 40 50 0 10 20 30 40 50 60 70 80 90 10060 70 80 90 100

Num

ber o

f conn

ected ecosystems

Num

ber o

f conn

ected ecosystems

Percentage of total system length (perennial streams)Percentage of total system length (perennial streams)

Current configuration of the Mekong, with over larger 50 damsCurrent configuration of the Mekong, with over larger 50 dams

Using a network connectivity algorithm Using a network connectivity algorithm we were able to determine that currently we were able to determine that currently 46 % 46 % of ecosystem connectivity is of ecosystem connectivity is preserved in the Mekong preserved in the Mekong

according to this ecosystem classificationaccording to this ecosystem classification

©WWF, 2011

Impacts on MekongImpacts on Mekong‐‐wide ecosystem connectivitywide ecosystem connectivity

Project name Capacity Impact on connectivity

Sayaboury 1,260 MW

Nam Theun 2 1,070 MW

Se San cascade 1,540 MW

©WWF, 2011

Sekong

Sesan

Srepok

Nam Ngum

Nam Theun

Tonle SapTonle Sap

Nam Chi

Nam Mun

Songkhram

Nam Ou

Jinhhong

Plei Krong

Yali

Se San 3

Se San 3a

Se San 4

Se San 4a ©WWF, 2011

Sayaboury

Impacts on MekongImpacts on Mekong‐‐wide ecosystem connectivitywide ecosystem connectivity

Project name Capacity Impact on connectivity

Sayaboury 1,260 MW 5.0 % decrease

Nam Theun 2 1,070 MW 0.8 % decrease

Se San cascade 1,540 MW 1.2 % decrease

©WWF, 2011

Overall ecosystem connectivity is very vulnerable to dam development on the main stem; the reproduction ofecosystem processes in the Mekong is extremely sensitive to the impacts of main stem dams because of its layout; a very long main stem fed by relative short tributaries

Overall ecosystem connectivity is very vulnerable to dam development on the main stem; the reproduction ofecosystem processes in the Mekong is extremely sensitive to the impacts of main stem dams because of its layout; a very long main stem fed by relative short tributaries

Conclusions and recommendationsConclusions and recommendations

• Work towards an open, consistent and reliable database of all existing dams in the Mekong basin, include planned dams

• Dams on the mainstream have disproportional impacts on the connectivity o f the ecosystems, compared to tributary dams

• Incorporate ecosystem processes connectivity as a guideline in basin‐wide dam planning

©WWF, 2011

Thank youThank you

The methodology, analysis, and maps in this presentation are under copyright of WWF‐2011, and need to be properly referenced and acknowledged when being re‐used.

Please contact us at:[email protected]@wwfus.org

http://www.worldwildlife.org/science/projects/freshwater/freshwater.html

http://wwf.panda.org/what_we_do/where_we_work/greatermekong/©WWF, 2011

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