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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
Connectivity applied to dams and large tributariesConnectivity applied to dams and large tributaries
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
Connectivity applied to dams and large tributariesConnectivity applied to dams and large tributaries
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
Connectivity applied to dams and large tributariesConnectivity applied to dams and large tributaries
Number of connected ecosystems
1234611
©WWF, 2011
SayabourySayaboury Nam Theun 2Nam Theun 2
Se San CascadeSe San Cascade
SayabourySayaboury
Number of connected ecosystems
1234611 9
©WWF, 2011
Nam Theun 2Nam Theun 2
Se San CascadeSe San Cascade
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