2011/9/20

WaterWt Quality
Q lit M
Monitoringit i att Reservoir
Ri offNam Ngum 2 Hydropower Dam and Upper
Reservoir of Nam Ngum 1 Hydropower Dam

By Souphasay Komany
Acting Director of Nam Ngum River Basin Committee Secretariat,
Department of Water Resources,
Ministry of Natural Resources and Environment
Email: souphasaykomany@yahoo.com and komany.s@gmail.com
1

Introduction: River Basins in Lao PDR

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Introduction: Hydropower Dams in NN RB

3

Introduction: NN1 Catchment Area42

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Introduction: Physical Features
DamDevelopment

Capacity

Catchment

Reservoir Storing
Capacity

NN1

Phase I: 1969 ‐1971

155 MW

8,460 Km2370 Km2615 MW

5,640 Km2 112.2(Share with Km2Upper
NN1)

7,030 Mil
m3Owner
Lao PublicEnterprise(EdL)

Phase II: 1976 ‐1978
Phase III: 1983 ‐1984
NN22005‐2009

3,590 Milm3

Joint
Venture ofEdL andInternatio
nal IPPs

5Objectives– To cooperate for optimization hydropower
development between NN1 Dam and NN2 Damby:• Monitoring water quality data at key defined stations
and parameters in designed period, in order to address
key water quality factors in the reservoirs and estimate
downstream impacts;• To collecting water quality data for reservoir operation
co‐planning and impact management.

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Methodology– Campaigns: 19 from Mid 2006 – Early 2011
– Stations: 9– Parameters: 20 measured• 9 parameters taken at sites• 11 parameters analyzed in Laboratories:– Environmental Research Institute Lab., MoNRE– Chinaimo Water Supply Lap., Vientiane Capital Water Supply
Enterprise784

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9105

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11126

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Methodology: Campaigns
Campaign

Date

SeasonCampaign

Date

Season1

Jul – 06

Rainy

11Jan – 09

2Sep – 06

Rainy

12May – 09Rainy

3Jan – 07

13Jul – 09

Rainy

4May – 07

Rainy

14

Sep – 09

Rainy

5Jul – 07

Rainy

15Jan – 106

Sep – 07

Rainy

16May – 10Rainy

7Jan – 08

17Jul – 10Rainy
Rainy

8May – 08

Rainy

18

Sep – 10

9Jul – 08

Rainy

19Jan – 11

10

Sep – 08

Rainy

13

Methodology: Monitoring Stations
Stations

Location

ST‐1

Nam Meuy(Nam Ngum2 Upstream Reservoir)
Nam Leuk(Nam Ngum2 Upstream Reservoir)

ST‐1
ST‐4

ST‐2

ST‐2

ST‐3

ST‐3

Nam Ngum2 Upstream Reservoir

ST‐4

Nam Ngum2 Upstream Reservoir
Nam Ngum2 Upstream
Near Dam Axis
Nam Ngum2gDownstream(Nam Ngum1 Reservoir)
Nam Ngum2 Downstream(Nam Ngum1 Reservoir)
Nam Ngum2 Downstream(Nam Ngum1 Reservoir)
Nam Ngum2 Downstream(Nam Ngum1 Reservoir)

ST‐5
ST‐6ST
6ST‐5

ST‐7

ST‐6
ST‐7

ST‐8
ST‐8
ST‐9

ST‐9147

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Methodology: Parameters
No.

Parameter

Unit

Remark1

Air TemperatureoC

Taken at site

2

Water TemperatureoC

Taken at site

3Depthm

Taken at site

4

Transparencym

Taken at site

5

Current Velocitym/sTaken at site

6DOmg/lTaken at site

7pH‐Taken at site

8Conductivity

s/cm

Taken at site

9TDSmg/l

Taken at site
15

Methodology: Parameters
No.

Parameter

Unit

Remark10Camg/l

Analysis in Laboratory

11Mg

mg/l

Analysis in Laboratory

12CImg/l

Analysis in Laboratory

13

SO4mg/lAnalysis in Laboratory

14

Total – Fe

mg/l

Analysis in Laboratory

15(NO3+NO2) – N

mg/l

Analysis in Laboratory

16

NH4 –N

mg/l

Analysis in Laboratory

17

PO4 – P

mg/l
g/Analysis
y in Laboratoryy

18

Total – P

mg/l

Analysis in Laboratory

19

TSSmg/lAnalysis in Laboratory

20

CODMn

mg/l

Analysis in Laboratory1682011/9/20

ResultParameter

Air Temperature
Water Temperature
Transparency
Current Velocity
DOpHConductivity
TDS

Upstream Num Ngum2((ST1‐ST5))

Num Ngum1 Reservoir((ST6‐ST9))The same in average value
The same in average value
The same in average value
The same in average value
Increase
The same in average value
The same in average value
The same in average value

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ResultParameter

Upstream Num Ngum2((ST1‐ST5))

Num Ngum1 Reservoir((ST6‐ST9))

CaThe same in average value

Mg

The same in average value

CIThe same in average value

SO4

The same in average value

Total – Fe

The same in average value(NO3+NO2) – N

The same in average value

NH4 –NThe same in average value

PO4 – P

Increase

Total – P

The same in average value

TSS

The same in average value

CODMn

The same in average value
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Result: DO• Campaign 4 (May – 07) and Campaign 14 (Sep – 09):
The DO values at station 1‐8
1 8 were in compliance withthe standard, except at station 9 in which DO values
were 5.07 mg/l and 5.16 mg/l, respectively.
• Campaign 19 (Jan – 11): at station 1‐5, DO values
declined dramatically to be lower than standard due
to decomposition of flooded plant under reservoir.

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DO at station 1‐9
12.0Standard
10.0
Station 1

DO mg/l

8.0

6.0

Station 2

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

Station 3

Station 4
4.0
Station 5
2.0

Station 6

Station 7

0.0
1

23

4

5

67

89

10111213

141516171819Station 8Campaign

Station 92010

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Result: PO4• Campaign 14 (Sep – 09): PO4 values at every station
was increased dramatically than usualusual.
• Campaign 15 (Jan – 10): At station 6‐9, PO4 values
were relatively increased, comparing to othercampaigns.
• These result were caused by different items ofcontaminations such as fertilizer
contaminations,fertilizer, detergents andsewage, and other contaminated water with highlevel of phosphate that promoted excessive algal
growth.
21PO4 at station 1‐91.200

Station 1Station 2

1.000

Station 3
0.800

PO4(mg/l)

Station 4Station 50.600

Station 60.400
Station 70.200

Station 8

Station 90.000
12345678910111213141516171819Campaign

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Conclusion and Recommendation– There is a need for more frequent intensive coordinationand cooperation between NN1 Dam and NN2 Dam at bothadministrative and technical levels in short‐term and long‐term.
– The immediate activities should include:• Regular exchange of NN2 water operation data for NN1 water
operation planning;• Exchange of water quality data on some rainy seasons as needed;• Install 3 more water quality monitoring stations, extended fromdownstream of NN1 Dam to the Nam Lik River Mouth.
• Pay more attention on water environment monitoring andmanagement.
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Detail Monitoring Results

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30

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36

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Thank You

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