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Module 2 Module 2 Mekong Resources,Mekong Resources,

Benefits to people, and Planning Issues Benefits to people, and Planning Issues

session 1 : The Mekong and its water session 1 : The Mekong and its water resources resources

Module 2 Module 2 Mekong Resources,Mekong Resources,

Benefits to people, and Planning Issues Benefits to people, and Planning Issues

session 1 : The Mekong and its water session 1 : The Mekong and its water resources resources

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Module ObjectiveModule ObjectiveModule ObjectiveModule Objective

Participants can identify Mekong water/ relate resources, current benefits to basin peoples, potentials for future development, and able to define key issues for planning water resources development.

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“..the Mekong River Basin and

the related natural resources and

environment are natural assets of

immense value…”

1995 Agreement

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• China• Myanmar• Laos• Thailand• Cambodia• Viet Nam

Discharge: 475 km3 / yearArea: 795,000 km2

Mekong River BasinMekong River Basin

Upper Basin

LowerBasin

Murray-DarlingDischarge: 12.6 km3 / yearArea: 1,073,000 km2

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Mekong River Basin

Upper Mekong Basin (UMB) 18 % of total flow (China 16% & Myanmar 2%)

Lower Mekong Basin (LMB)

625,000 km2

82 % total flows Cambodia – 18% Lao PDR– 35% Thailand – 18% Viet Nam – 11%

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MRB water resourceMRB water resourceMRB water resourceMRB water resource

Description China Mya Lao Thai Cam V/N Total

Catchment (Km2 )

165,000 24,000 202,000 184,000 155,000 65,000 795,000

% of Basin 22% 3% 25% 23% 19% 8%

% of country

4% 97% 36% 86% 20%

Average Flow (m3/s)

2,410 300 5,270 2,560 2,860 1,660 15,060

Percentage 16% 2% 35% 18% 18% 11%

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Main regions in the Mekong Main regions in the Mekong Main regions in the Mekong Main regions in the Mekong

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Main regions

• Upper Mekong Basin

Mekong River BasinMekong River Basin

For most of its length, it flowsThrough narrow valleys in the Mountain in China. UpperBasin is narrow, with few tributaries And gives 18% of the total flow

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Manwan and Dachaoshan dams,

Feb 2003

20 km

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Main regions• Upper Mekong Basin• Lower Mekong basin

•Highlands

Mekong River BasinMekong River Basin

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12

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Mekong River BasinMekong River Basin

Main regions

• Upper Mekong Basin• Lower Mekong

• Highlands• Central/Isan Plateau

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Mekong River BasinMekong River Basin

Main regions

• Upper Mekong Basin• Highlands• Central / Isan Plateau• Cambodian plain and

Great Lake

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Mekong River BasinMekong River Basin

Main regions

• Upper Mekong Basin• Highlands• Isan Plateau• Cambodian plain and

Great Lake• Delta

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Flow regime Flow regime Flow regime Flow regime

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Hydrological RegimeHydrological RegimeHydrological RegimeHydrological Regime Hydro. Regime depends on climatic conditions

of wet and dry seasons. High water period from Sept – Nov; Low flow

period from Feb. – April.

Flood season in mainstream and tributaries, from June-July to Nov-Dec accounts for 85-90% of total annual water volume.

Peak month of Sept accounts for 20-30% of annual flow.

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Monsoonal climate

• dry season November to May

• wet season June to October

35%

20%

Contribution to Mekong flows

16%

ClimateClimate

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T he M ekon g at P akse, maximum, mean , min imum fl ow ( 19 2 5 - 2 0 0 1)

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

J an Feb Mar Apr May J un J ul Aug Sep Oct Nov Dec

MEAN MONTHLY

MONTHLY MAXI MUM

MONTHLY MI NI MUM

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The % contribution of flow from ChinaThe % contribution of flow from Chinato average monthly flow at …to average monthly flow at …

%%

Flow from China dominates the dry season hydrology of the Lower Mekong

Flood season flows mostly originate within Laos and the lower basin

The % contribution of flow from ChinaThe % contribution of flow from Chinato average monthly flow at …to average monthly flow at …

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Daily flow at Kratie

0

10,000

20,000

30,000

40,000

50,000

60,000

Date

Flo

w (

cu

me

cs

)

2000

1998

20 m

River variability

Flooding

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Extent of Extent of flooding in LMBflooding in LMB

Extent of Extent of flooding in LMBflooding in LMB

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Water quality

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3 commonly identified 3 commonly identified

water quality issueswater quality issues 3 commonly identified 3 commonly identified

water quality issueswater quality issues

Sediments in the waterSalinity ( NE Thai & VN Delta) Eutrophication

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Trends in total suspended sediment (TSS) in the Lower Mekong Basin

Water quality Water quality monitoringmonitoring

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TSS before and after filling TSS before and after filling Manwan DamManwan Dam

TSS before and after filling TSS before and after filling Manwan DamManwan Dam

TSS at Chaeng Saen (1985-1992)

0

500

1000

1500

2000

2500

Feb-82 Nov-84 Aug-87 May-90 Jan-93 Oct-95 Jul-98 Apr-01 Jan-04

DATE

TS

S (

mg

/L)

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SalinitySalinity SalinitySalinity

In NE Thailand where there has been concerns for salinity, 4 of 5 sites show a decrease

most concern sites in Vietnam (9) show also a decrease.

Eutrophication Eutrophication Eutrophication Eutrophication

Mostly a problem in VN delta – 40 sites in the delta show an increase in phosphorus – 31 site in delta show increase in nitrogen

– ( both N & P are parameter used eutrophication)

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Water quality Water quality Water quality Water quality

In summary It is quite good when compare with

many other international rivers !