1) The document summarizes key baseline findings from an environmental study of the Lancang-Mekong River, including descriptions of three zones along the river with differing geomorphological characteristics. 2) Major findings include the identification of deep pools that are dry season fish habitats, changes to hydrology and sediment levels from Chinese dams, declines in the status of aquatic ecology indicators, and high fish diversity including endangered species that use deep pools. 3) Key drivers of environmental changes in the region include dams in the upper Mekong, land use changes, development activities, and increased pressures from activities like fishing, hunting, and agriculture.

1. Final Workshop: 10 December 2018, MRC, Vientiane
Peter-John Meynell
Environmental Study of the
Lancang-Mekong Development Plan
Baseline assessment findings – key issues, trends and
drivers

3. Zone descriptions
• ZONE 1 - Open flood plain and wide channel with sandy bed and banks
– relatively more developed
– wider channel and sandier with more and larger sand islands and wetlands
– mostly flat terrain
– large alluvial floodplains with cropping or settlements
– fewer rocky outcrops and dangerous areas
• ZONE 2 - Narrow steep channel mainly bed rock with V shaped valley
– narrower, more incised, straighter and rockier
– steep with short steep valleys running perpendicular to the river
– many small tributaries
– less developed with no large towns and has significant forest cover
– more dangerous areas for navigation
– few vegetated islands, sandbanks and wetlands
• ZONE 3 - Multiple rapids and rocky outcrops in broad channel mixed bed rock and
sandy substrate
– relatively narrow and rocky
– steep forested terrain and many dangerous areas
– valleys parallel to the river
– many small tributaries entering
– many deep and very deep pools associated with the river cutting through mountain ridges and
dangerous areas for navigation
– river widens and development increases closer to and including Luang Prabang

4. 1. Rapids/shoals
2. Tributaries/deltas
3. Vegetated islands
4. Off-main channel
wetlands
5. Deep pools
6. Rocky outcrops
7. Sandbanks

5. 0
5
10
15
20
25
30
35
Zone 1
Zone 2
Zone 3

6. A ‘fly over’ of the target Mekong River
PJ to show Google Earth Fly-over

7. KEY BASELINE FINDINGS: BATHYMETRIC
SURVEY (SWIM UNDER)
7
• Deep pools: dry-season refuge for fish; spawning habitats
• 52 fish species known to make use of deep pools
• 19 deep (5 – 20m) and 10 very deep (up to 90m) pools
• Each pool - 10 to 15 ha
• Very deep pools concentrated between Pak Beng dam site
and Pak Ou

8. KEY BASELINE FINDINGS: HYDROLOGY &
SEDIMENT
• Increase in dry season flows, decrease in wet season flows due to China
dams
• Significant reduction in suspended sediment concentrations at Chiang Saen
after 1992 dams
• Land use changes - some evidence of increased sediment loads due to
tributary contributions in study zone with implications for reservoir

9. KEY BASELINE FINDINGS: HYDROLOGY &
SEDIMENT
Percentage of average flow originating in each countryduring
 wet – June to November (left – 55% from China in study area)
 dry – December to May (right – 75% from China in study area).
The study section is indicated by the red arrows
MRC 2005

10. KEY BASELINE FINDINGS: HYDROLOGY &
SEDIMENT
Comparison of pre and post Manwan reservoir construction TSS concentrations at
Chiang Saen (left) and Luang Prabang (right) (Adamson, 2009)

11. KEY BASELINE FINDINGS:
AQUATIC ECOLOGY
Changes in status of indicators for geomorphology, aquatic vegetation and macroinvertebrates
between 1985 and 2015 (MRC Council study – BioRa)
•Water quality and river health
good; gradual decrease in Aquatic
Ecology Health Index since early
2000s
•Considerable changes in the
geomorphology, especially erosion
•Decrease in the status of channel
biomass of riparian vegetation
•Macroinvertebrate indicators in
upper reaches natural in 1985, but
many downstream of Pak Beng
moderately modified
•By 2015 most macroinvertebrate
indicators above Pak Beng become
moderately modified
Indicator 1985 2015
China border
to Pak Beng
Pak Beng to
Vientiane
China border
to Pak Beng
Pak Beng to
Vientiane
Geomorphology
Erosion A A D D
Average bed sediment size in dry season A A B B
Availability of exposed sandy habitat in dry season A A C C
Availability of inundated sandy habitat in dry season A A C C
Availability of exposed rocky habitats in dry season A A C C
Avaialbility of inundated rocky habitats in dry season A A C C
Depth of pools in bedrock in dry season A A B B
Water clarity A A C C
Aquatic Vegetation
Channel extent of upper bank vegetation C C C C
Channel extent of lower bank vegetation C C C C
Channel biomass of riparian vegetation B B C C
Macroinvertebrates
Insects on stones B B B B
Insects on sand B B B B
Dry season emergence B C C C
Burrowing mayflies B C C C
Snails B C C C
Aquatic snail diversity B C C C
Bivalves B B B B
Shrimps and crabs B C C C
Littoral invertebrate diversity B C C C
Benthic invertebrate diversity B C C C
Zooplankton B B B B
A Unmodified, natural
B Largely natural
C Moderately modified
D Largely modified
E Completely modified

12. KEY BASELINE FINDINGS: FISH
The study area has exceptionally high species diversity and concentration of
Mekong endemics given its limited surface area (compared to the two larger
scales).
• 199 native fish species (7 endemic and 38% migratory) in study area
• Exceptionally high species diversity and concentration of endemics
• 12 species on Red -List as critically endangered and endangered, 32 near threatened and vulnerable
• Deep pools dry-season refuge for fish and spawning habitats - 52 species make use of deep pools
• Fish abundance, size and diversity declined in past 5 – 10 years
• Significant presence of invasive exotic fish species
Study Area

13. KEY BASELINE FINDINGS: BIRDS
• No endemics
• 7 potentially threatened (limited info)
• 32 extinct
• Avifaunal collapse over the past 100–150 years, due to ordinary human activities

14. KEY BASELINE FINDINGS:
AMPHIBIANS AND REPTILES
• 25 amphibian and reptile species observed and 7 reported
• 8 species (6 turtle species and 2 snake species) globally and nationally threatened
from overexploitation for food and traditional medicine

15. KEY BASELINE FINDINGS: NAVIGATION /WATERWAYS
15
• 22 rapids and shoals between Huay Xay and Luang Prabang
• No major improvements for navigation downstream of Chiang Saen
• Minor removals of obstacles in Lao PDR
• New Chiang Saen Port: capacity for 10 small, 4 large (300 DWT) boats
• 32km (33%) hardened river banks on Thai section
• Consequent geomorphological changes and bank erosion on the Lao side
• Cargo flows increased significantly from 2004-14

16. KEY BASELINE FINDINGS: SOCIO-ECONOMICS
• Poverty rates and minority numbers
high
• Fish important for food security
• Agribusiness undermining livelihoods
of vulnerable groups
• Land titling a key issue
• GT a hotspot for wildlife trade
Lao-Tai Mon-Khmer Hmong Lewmien Sino-Tibetan
ZONE ONE
Left bank population 21,100 16,200 8,600 10,400
Right bank population* unknown unknown unknown unknown
ZONE TWO
Left bank population 1,600 1,800 700 700
Right bank population 2,300 800 500 300
ZONE THREE
Left bank population 2,900 6,900 1,700 400
Right bank population 1,800 900 400 0
Province Poverty rate
2013
Change in poverty
rate since 2008
Oudomx
ay
30.1% -3.6%
Luang
Prabang
25.5% -1.7%
Xayabury 15.4% -0.2%
Bokeo 44.4% +11.8%

17. Key drivers of change…
Hydrology and sediment
 Upper Mekong dams
 Land clearing and
deforestation
 Embankment developments
 Climate change
Aquatic ecology
 Changes of land use in the
watershed
 Changes in agriculture down to the
river banks
 Increases in urban run-off and
pollution
 Increases in infrastructure
development.
 Navigation improvements
 Increase in navigation traffic
Fish
 Deteriorating water quality
 Declines in benthic fauna and
flora
 Changes in water level
 Increasing fishing pressure
 Decline in algae
Amphibians and reptiles
 Land clearing and
development
 Forest degradation
 Agriculture (banana, rubber,
rice)
 Infrastructure
Birds
 Local hunting pressure
 Dogs and rats
 Disturbance to nests and habitats
Socio-economics
 Annual population growth rates
ranging from 0.38% in Chiang
Rai, up to 2.1% in Bokeo
 Promotion of agri-business is
coming at the expense of the
livelihoods and food security of
poor and vulnerable
communities
 Illegal logging is continuing to
grow

18. THANK YOU