Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

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Impacts of Climate Change on Catchment
Flows and Assessing Its Impacts on
Hydropower in Vietnam’s Central Highland
Region
Ho Quoc Bang1*, Nguyen Hong Quan1, Vo Le Phu2
*Institute for Environment and Resources (IER), VNU-HCM, Vietnam, 142 To Hien Thanh st., Dist.10, HoChiMinh,
Vietnam
1

Ho Chi Minh City University of Technology / VNU-HCM, 268 Ly Thuong Kiet St., Dist. 10, Ho Chi Minh City,
Vietnam
2

1*

, 1 ;

Abstract
According to the Fourth Assessment Report – AR4 in 2007 of
the Intergovernmental Panel on Climate Change (IPCC),
climate change is a complex problem and becoming the
leading challenge for humankind in the 21st century. Therefore,
assessing climate change impacts on the social, economic
activities and proposed solutions to respond to climate change
is urgent and necessary. This study applied the GIS
(Geographic Information System) technique and SWAT model
(Soil and Water Assessment Tool) to simulate water flows due

to the impact of climate change. The models were applied for
several catchments in and around Dak Nong province. The
results of catchment flows can be useful information for many
purposes, such as: flood forecasting, predicting sediment loads
and impact assessment of climate change on water resource
and hydropower. In this study, the issues of hydropower
safety and electricity generation capacity in Dak Nong up the
year of 2020 are focused. The results of SWAT model show
some certain changes in catchment flows due to climate
change, for example, the maximum streamflow in the upper
part of Serepok River in 2020 is higher than that in the period
of 2005 to 2010 about 16.8%. The results also showed that the
hydropower dams’ safety in Dak Nong province is secured
given the climate change scenarios. In addition, given the
changes in catchment flows due to climate change ， the
hydroelectric ouput of Dak Nong in 2020 are only 7,063 million
kWh/year, which is less than about 12% in comparison to the
expected production.
Keywords
Climate Change; Swat Model; GIS; Hydropower; Vietnam

Introduction
According to the IPCC’s Fourth Assessment Report
(AR4), climate change is a complex problem and
becoming the leading challenge for humankind in the
21st century (IPCC, 2007). Many studies showed that
climate change is mainly caused by the emission of
greenhouse gases (mainly CO 2 and CH 4 ). Especially
since 1950, the rapid growth of urbanization and
industrialization had led to an acceleration of human

consumption and an increase in emissions. One of the
biggest industries greenhouse gas emissions is electricity
production which occupies about 50% of global CO 2
emissions (Lansiti, 1989). Because electrical industry
emits a large amount of greenhouse gases, therefore the
energy sector has to cut greenhouse gas emissions for
mitigation of climate change. Many solutions have been
given to the energy sector, such as: using other fuels
producing less CO 2 , using modern energy efficient
alternatives or increasing use of renewable energy
sources. Among the alternative power production in
thermal power, hydropower is an attractive option
because hydropower is a form of renewable energy, less
greenhouse gas emissions and hydropower infrastructures have a long lifetime. Therefore, in recently years,
although the construction of large-scale hydropower
dams have made locals emigrate and caused ecological
impacts on the basin, governments in most countries
have still continued to construct more hydropower
plants because of its important role played in the econo-

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Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

FIG. 1 LOCATION OF DAKNONG PROVINCE IN VIETNAM (LEFT) AND ITS TOPOGRAPHY (RIGHT)

mic development, especially in developing countries

and less developing countries.

12o50’ northern latitude and 107o13’ - 108o10’ eastern
longitude.

It is estimated that there will have 69 hydropower
projects in Dak Nong province, Viet Nam by 2015.
According to the Dak Nong industry and trade
department, 37 hydroelectric projects (including 25
small-scale and 12 large-scale hydropower facilities)
have been investing and operating in 2010 with a total
capacity of 1905.96 MW. However, the massive
hydroelectric development in recent years can be
affected by climate change in the future. The change of
water flow is likely one of the potential impacts in the
age of human-induced climate change. Hence, for ease
on the impact of climate change on hydropower
systems in Dak Nong, this paper presents an
application of GIS (Geographic Information System)
and SWAT (Soil and Water Assessment Tool) model to
simulate water flows, then results of the model are
used for assessing climate change impacts on
hydropower in Dak Nong province.

The province’s climate condition is influenced by
the climate of eastern and western of Truong Son moutain

Study location, data and methods
Study Location
Dak Nong is located in the southern part of Vietnam’s

Central Highland region (FIG. 1). Dak Nong borders
with Dak Lak in the north, Lam Dong in the southeast, Binh Phuoc and Cambodia in the west. Its
elevation is about 500m above sea level. The terrain is
lower in the west. Dak Nong coordinates at 11o45’ -

2

range. It is characterized by less directly affected by
storm, high temperatures and solar radiations. The ave-

rage annual temperature is about 21 - 24oC. Total
yearly hours reach 2,200 - 2,400 hours/year. Total amount
of
radiation
is
233
240 Kcalo/cm2. Annual evaporation, relative humidity
and rainfall are abour 1,000 - 1,400 mm, 81 - 85%
and 1,600 - 2,500 mm respectively (Nguyen and Ho.,
2011).
Dak Nong has two main river basins, including Serepok and DongNai rivers. Almost area of the province is
in the Serepok river basin and the remain-ing part
is the DongNai river basin. The Serepok river has two
major tributaries which are KrongNo and KrongAna
rivers. The total area of KrongNo river basin
is 4,620 km2 and the main stream is 56 km in
length. KrongAna river has a total river basin is
3,200 km2, and the legnth of the main river section is 215
km. The DongNai river basin covers an area of approxi
mately 2,526 km2 (Ngu-yen and Ho., 2011). The stream

nerwork in the provin-ce is quite complex, thick
and many small tributaries. These are favorable
conditions to exploit water resour-ces for agricultural


Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

practices, hydropower pro-duction and domestic uses.
Data Collection
Collected data in the catchments are meteorological
and hydrological data in many stations in and around
Dak Nong (including Cau14 station, GiangSon station,
DakMil station, DucXuyen station and Dak Nong station). The collected data are (1) daily evaporation; (2)
hourly rainfall; (3) wind direction and speed; (4) hourly
temperature; (5) hourly humidity and (6) hourly streamflow.
Land use map is provided by the Dak Nong Department of Natural Resources and Environment, while the
topographic map is collected at the Vietnam National
Information and Communication Technology Department at 1:25.0000 Scale, which can be used later for
generating a Digital Elevation Model (DEM). Climate
change variations are up the year of 2030, including
temperature, rainfall, and evaporation from the Vietnam Institute for Meteorology, Hydrology and Environment (IMHEN, 2007).

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(EPIC) (Williams et al., 1984). Many docu-mented
applications of SWAT model for assessing water
resources have are Van Liew and Garbrecht (Van et
al., 2003) using the SWAT model to predict streamflow under varying climatic con-ditions for
three nested watersheds in Little Washita River
Experimental Watershed in Okla-homa. Chu and

Shirmohammadi (2004) (Chu et al, 2004) applying
SWAT model for the calculation of surface flow for
a small watershed in Maryland. Spruill and others
(Spruill et al., 2000) using SWAT model to determine
daily streamflow for a small karst-influenced
watershed in central Kentucky during the period of
2 years, etc.
2)

SWAT’s application in Dak Nong province

Methods
1)

SWAT model

The SWAT model was developed in the early 1990’s
by the U.S. Department of Agriculture, Agricultural
Research Service (USDA–ARS) (Arnold et al., 1998).
The model was developed to assess and predict the
impact of land management affect on water, sludge,
and the amount of chemicals used in agricultural
practices on a large and complex basin with
unstable factors of soil, landuse and management
conditions in a long time. The model includes a set
of regression calculations to describe the relationship between the input and output parameters. The
SWAT model integrates many different models of
ARS, which are developed from model for Simulator for Water Resources in Rural basins (SWRRB)
(Williams et al., 1985; Arnold et al., 1990). Specific
models that contributed significantly to the

development of SWAT model were: (i) Chemicals,
Runoff, and Erosion from Agricultural Management Systems (CREAMS ) (Knisel, 1980); (ii) Groundwater Loading Effects on Agricultural Management Systems (GLEAMS ) (Leonard et al., 1987);
(iii) and Erosion-Productivity Impact Calcu-lator

FIG. 2 DESCRIBES THE APPLICATION PROCEDURE OF
SWAT IN DAKNONG, VIETNAM

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3)

Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

Model calibration and validation

The SWAT model was calibrated by using SWATCUP software. Several statistical approaches can be
used to check SWAT model performance such as:
coefficient of determination (R2), Nash-Suttcliffe
Simulation Efficiency (NSE) (Nash and Suttcliffe,
1970), mean absolute error (MAE), Root Mean
Square Error (RMSE), and Theil’s inequality coefficient (U).
+ Nash-Suttcliffe Simulation Efficiency (NSE).

0.89, 0.84 for Dak Nong station, DucXuyen station
and Cau14 station, respectively. These NSE values
are almost higher than 0.7, therefore the model and
the parameters can be used to simulate catchment

flows in the province under climate change scenarios.
Results and discussions
Results of streamflow
The continous of monthly streamflow at the Cau 14
station and some statistical numbers of streamflow of
four catchments in Dak Nong province are shown in
FIG. 4 and TABLE 1.

Where: P is simulation values ; O is measurement
values and N is the number of monitors.
+ SWAT-CUP is a computer program for calibration
of SWAT models. The program links GLUE, ParaSol,
SUFI2, MCMC, and PSO procedures to SWAT. It
enables sensitivity analysis, calibration, validation,
and uncertainty analysis of a SWAT model. The
program structure approach is as shown in the FIG.
3.

FIG. 4 PREDICTED DAILY STREAMFLOW IN 2030 AT CAU 14
STATION, DAKNONG

FIG. 3 SWAT-CUP APPROACH

In this paper, the Nash-Suttcliffe simulation
efficiency was used. The statistic results of the
average NSE between simulations and measurements for model calibration and validation are 0.86,

4

FIG. 5 PREDICTED MONTHLY STREAMFLOW IN 4 PERIODS AT

CAU 14 STATION, DAKNONG


Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

FIG. 6 PREDICTED YEARLY STREAMFLOW IN 4 PERIODS AT CAU
14 STATION, DAKNONG
TABLE 1 STREAMFLOW IN 2005-2010, 2015 AND 2020 AT 4
CATCHMENTS (M3/S)
Serepok

Krong
No

DongNai’s
main stream

Dak Nong
station

Maximum

2210

1290

2600

147


Average

272

87.4

1110

18.2

Minimum

16.4

0.9

215

1.3

Maximum

1789.7

1263.5

1647.7

93.2


Average

220.3

85.6

703.4

11.5

Minimum

13.3

0.9

136.3

0.8

2120.8

1507.2

2050.7

115.9

Average


261

102.2

875.5

14.4

Minimum

15.7

1.1

169.6

1

Streamflow
2005-2010

2015

2020
Maximum

Assessing Climate Change Impacts on Hydropower
1)

Climate change impacts on hydropower safety


Climate change likely leads to increased intensity of
floods and the flood peak. In some extreme cases,

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the hydropower plant has to discharge to ensure
the safety of hydropower dams in the flood season.
Streamflows and flash flood levels are the parameters used to assess the impact of climate change
on the safety of hydropowers (Thang et al., 2010).
Thus, the changes of streamflows due to climate
change from SWAT model simulations and the
design flash flood flows of each hydropower
(TABLE 2) are used to assess the impact climate
change on the hydropower safety. The results show
that the design flash flood flows of 37 hydropowers
in Dak Nong are higher than the maximum level of
streamflows in Dak Nong’s catchments, although
the maximum level of streamflows in some river of
Dak Nong’s catchements in 2020 are higher that in
the period of 2005 to 2010. Such as the maximum
level of streamflows in Krong No river is 1507.2
m3/s in 2020, while the maximum level of
streamflows in the period of 2005 to 2010 is only
1290.0 m3/s (TABLE 1). Therefore, the hydropower
dams’ safety in the province is secured given the
climate change scenarios.
2)

Climate change assessment impacts on

electricity generation capacity

Climate change refers to any significant change in
climate factors, including precipiration, temperature, storm patterns and intensity, etc. The decrease
of precipitation or increase of temperature will
likely result in drought events. Drought and reducing streamflow lead to the reduction of hydropower supply (Cherry et al., 2010). Therefore, the
change of streamflows from SWAT model simulations due to climate change and the expected streamflows for generating maximum electicity are used to assess the impact of climate change on electricity generation capacity in Dak Nong pro-vince
(TABLE 2). The results showed that the hydroelectric output in 2010 is about 5,450 million kWh/year. It is expected that the hydropowers are not affected by reduced streamflow due to climate change,
and in 2020 the hydroelectric output will reach
to 8,072 million kWh/year. However, the
hydroelectric ouput of Dak Nong in 2020 is
only 7,063 million kWh/year. However, production
tends to decrease as it is less than about 12%
in comparison with the proposed production due to
the impact of human-induced climate change.

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Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

TABLE 2 TECHNICAL SPECIFICATIONS OF HYDROPOWERS IN DAKNONG
Hydropower
name

River Basin

Q design flash

flood flow (m3/s)

Material
of dams

Q generated max
electricity(m3/s)

Annual electricity
generated (106 kWh)

Dak Buk Sor 1
Dak Sin
Dak Kar

DongNai
DongNai
DongNai

746.02
552
683

7.82
12.31
5.72

11.76
105.18
30.52


Dak R’Keh
Dak A.Kong
Dak Ru
Quảng Tin

DongNai
DongNai
DongNai
DongNai

331.5
242.8
758
460

6.85
4.3
10.3
6.7

11.09
7.46
29.8
20.3

Dak Glun 2
Dak Glun 3
Dak Sor 1
Dak Sor 2


DongNai
DongNai
Serepok
Serepok

394.03
458.6
645
590.7

5.8
8.75
5.9
9.74

13.73
25.63
18.326
22.64

Dak Sor 4

Serepok

721

Soil dam
Soil dam
Soil dam

Beton
dam
Soil dam
Soil dam
Soil dam
Beton
dam
Soil dam
Soil dam
Soil dam
Beton
dam

17.62

27.6

7.53
14.9
13.2
8.36
11.57
5.45
7.82
-

42.33
26.321
31.8
52.8

5.995
19.05
11.76
64.09
8.01
7.21

19.37
8.71

58.688
25.51

2.04

9.55

507.42
316

336.36
1458

204.9

358.6

412.8
-


1060.2
118.4

215

607.1

50/67

636.8

221

1109.5

298
-

604.43
929.16
37

-

132.5

Da Klong
Dak Rung 1
Dak Rung
Dak N’Teng

Nhan Co (ĐR)
Dak Mam 2
Dak Buk Sor 1
Dray H'linh 2
Dak Nong
Dak Nong 1

DongNai
DongNai
DongNai
Serepok
DongNai
Serepok
DongNai
Serepok
DongNai
DongNai

384
525
576
431
384.5
356.3
746.02
-

Dak Nong 2
Dak Nir


DongNai 1
DongNai 1

753
170.5

Dak Muong

DongNai

123

Serepok 4
Buon Kuop

Serepok
Serepok

9592.2
8000

Krông Nô

4267

Buon T. Srah

6

Serepok 3

Day H'linh 1

Serepok
Serepok

8760
-

DongNai 3

DongNai

10400

Dak R’Tih

DongNai

2360

DongNai 4

DongNai

10000

DongNai 5
DongNai 6
Chu P.Prong


DongNai
DongNai
Serepok

8320
-

Hoa Phu

Serepok

-

Beton
dam
Soil dam
Soil dam
Soil dam
Soil dam
Soil dam
Soil dam
Beton
dam
Soil dam
Beton
dam
Beton
dam
Soil dam
Beton

dam
Beton
dam
Beton
dam
Beton
dam
Beton
dam
Beton
dam
Note: “-“: Non-value


Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

Conclusion
The results of SWAT model show some certain changes
of catchment flows due to climate change, for example,
the maximum streamflow in the upper part of the
Serepok river in 2020 is higher than that in the period of
2005 to 2010 about 16.8%. It also shows that the
hydropower dams’ safety in Dak Nong province is
secured given the climate change scenarios. In addition,
given the changes of catchment flows, in 2020 the
hydroelectric output will reach 7,063 million kWh/year(less than about 12% in comparison with the expected
production).

IPCC.,


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2007.

Climate

Contribution

Change

2007:

Synthesis

Report.

of Working Group II to the Fourth

Assessment Report of the Intergovernmental Panel on
Climate Change. Cambridge University Press, Cambridge.
Knisel, W. G., 1980. CREAMS: A field scale model for
chemicals,

runoff,

and

erosion

from


agricultural

management systems, U.S. Dept Agric. Conserv. Res.
Report No. 2
Lansiti, E., and Niehaus, F., 1989. Impact of energy production
on atmospheric concentration of greenhouse gases Energy
systems must be restructured to reduce emissions of

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and Environment.

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Global Perspectives on Geography (GPG) Volume 1 Issue 1, February 2013

Bang Q. Ho was born in Vietnam, on
17/12/1979. He got Docteur ès Sciences
(Ph.D.) degree on Environmental Science
(Emission inventories and air quality
modelling) at the Swiss Federal Institute of
Technology in Lausanne (EPFL), Switzerland in 2010. He is doing research on
Climate Change, Energy and Air quality
fields.
He got Master degree on Environmental Science at the Swiss
Federal Institute of Technology in Lausanne (EPFL),
Switzerland in 2005. From 1997 to 2001: he did Bachelor of
Analytical Chemistry at the University Sciences Natural /
Vietnam National University in Ho Chi Minh City. From 2001

to 2011 he has worked for several Labs in IER (System
laboratories lab, Air quality lab), EPFL (LPAS, LASIG) and also
in French National Center for Scientific Research - France on
Emission inventory, Modelling of Meteorology and Air
pollution, monitoring of air quality and water quality, Climate
change. In 2011 he worked at Duke University, USA as visiting
scholars on Energy and Environment. He is doing as a
National Consultant and Regional consultant on Air emission
inventories for ASEAN Ports funded by German Technical
Cooperation (GIZ).
Dr. Ho is currently a Director of Air Pollution and Climate
Change Department/Institute of Environment & Resources

8

(IER)/Vietnam National University, HoChiMinh City (VNU/HCM). He teaches many courses on “Sustainable Energy
Use”, “Climate Change”, “Control of air pollution and noise”
and “environmental modelling” for master and engineer
levels.
Hong Q. Nguyen was born in Vietnam, on
22/12/1979. He got Docteur ès Sciences
(Ph.D.) degree on Environmental Science
Braunschweig Uni-versity of Technology.
He is doing resear-ch on Climate Change,
water management fields.
Dr. Quan is currently a vice director of
natural resources management depart-ment / /Institute of
Environment & Resources (IER)/Vietnam National University,
HoChiMinh City (VNU/HCM).
Le P. Vo was born in Vietnam, on

9/6/1971. He got Docteur ès Sciences
(Ph.D.)
degree
on
Environmental
Science Adelaide, Sou-th Australia,
Australia. He is doing resear-ch on
Climate Change, water management
fields.
Dr. Vo is currently a Vice Dean of Environment Faculty, of University of technique / Vietnam
National University, HoChiMinh.