SWAT Soil & Water Assessment Tool

From Large-Scale Rubber Plantations to Oil Palm Plantations:

Simulating the Impact on Leaf Area Index and Eventual River Flow

(..a work in progress)

Noradila Rusli Faculty of Built Environment Universiti Teknologi Malaysia

M. Rafee Majid Centre of Innovation & Planning Development (CIPD) Faculty of Built Environment Universiti Teknologi Malaysia

Muar River

East

Malaysia

STU

DY

AR

EA

Muar River Watershed Johor, Malaysia

Northern part of Muar River watershed Total Area: 2982.83 km2

Malaysia

THE

ISSU

E Increased Incidences of Flooding ..and magnitudes too.

Figure : Flood occurrences in a Muar River

1937 – 1984 (45 years): 0.31 flood/yr 1984 - 2007 (23 years): 1.08 floods/yr

Floods occur during Northeast Monsoon (Nov. – March) ..lately with devastating effects

THE

SUSP

ECT Succession of vast LU/LC changes

..different land covers hosting different types of plants with different physiologies.

to rubber (up to late 70s)

to oil palm (starting 1980s).

..from original forest (up to 1960s)

0

100

200

300

400

500

600

700

800

500

1000

1500

2000

2500

3000

35001974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

Oil Palm Malaysia(x10 000 hectare)

Oil Palm Price(US Dollar pertonne)

Linear (Oil Palm Price(US Dollar pertonne))

Production of

crude palm

oil

Total export

(Million

tonne)

Contribution to

Malaysia's economy

(RM Billion)

2000 10.84

million tonne

10.84 14.85

2002 11.748

million tonne

10.16 11.33

2003 13.35

million tonne

12.25 22.14

2009 17.56

million tonne

17.56 49.60

Oil palm area vs. Oil palm price

Rubber price (1960-2000)

Hectare US Dollar

FOREST’s INTERCEPTION of RAINFALL..

• Only 10% of the rainfall reaches a stream as runoff. • Tree leaves, twigs, branches, trunks, and stems, along with the forest floor litter, create an extensive surface area that intercept rainwater and allow much of it to evaporate before reaching the soil •Interception by forests and individual tree canopies is much greater than that by shrubs and other herbaceous plants (Pitman, 1989)

HEVEA BRASILIENSIS (RUBBER) CHARACTERISTICS

•The plant, growing up to over 40 meters (m) in the wild, characteristically does not exceed 25 m in height when it is under cultivation •During wintering (lasting for 4-6 weeks), the leaves of the tree die and fall off- create ‘sponge’ effect. •LAI : LAI rubber < LAI forest

Canopy Leaf Stem

RA

INFA

LL IN

TER

CEP

TIO

N I

N

RU

BB

ER T

REE

S

net rainfall entering the soil

throughfall

stemflow stemflow

Litter interception &

evaporation

Litter interception &

evaporation

Canopy interception &

evaporation

ELAEIS GUINEENSIS (PALM OIL) TREE CHARACTERISTIC

•Each tree can grow up to 18 meter and produces compact bunches

Bare floor

11

Bare floor Bare floor

Canopy interception &

evaporation

Higher runoff

Higher runoff

Small net rainfall entering the soil

Leaf : More throughfall Bare Floor : Higher water runoff, higher velocity– less infiltration LAI: LAI palm oil < LAI rubber < LAI forest

RAINFALL INTERCEPTION IN ELAEIS GUINEENSIS (PALM OIL)

Rubber old growth Oil palm

Mean LAI value

Mean LAI Value Land cover Type 2002 2006 2008 Forest 4.27 3.85 2.06

Oil Palm 2.54 2.83 1.05

Rubber 2.65 2.54 0.85

Overall LAI 3.54 3.30 2.50

DA

TA IN

PU

T

ASTER Digital Elevation Model (DEM)

Rainfall

Temperature

Relative humidity

Wind speed Solar Radiation

FLOW DISCHARGE

CLIMATE DATA

TOPOGRAPHY

LANDUSE SOIL LEAF AREA INDEX (LAI) MOD15A2: Level-4 MODIS global LAI

AST

ER D

EM (

30

Met

er)

LAN

D U

SE

(20

02

,20

06

,20

08

)

Year

19

70

- Y

ear

20

11

LAI’s Value = MODIS LAI x scale factor (0.1)

RESULTS D

om

inan

t La

nd

Co

ver

Ch

ange

s

Year 2006 Year 2008 Year 2002

0

5

10

15

20

25

30

35

40

Oil Palm Rubber Forest Other

2002

2006

2008

(%)

Oil Palm Rubber Forest

Land cover 2002 2006 2008

Rubber 35.59% 27.84% 28.37%

Oil Palm 25.54% 35.09% 35.31%

Forest 24.48% 23.01% 22.64%

Other 14.39% 14.06% 13.69%

Mean LAI Value Land cover

Type 2002 2006 2008

Forest 4.27 3.85 2.06

Oil Palm 2.54 2.83 1.05

Rubber 2.65 2.54 0.85

Overall LAI 3.54 3.30 2.50

Forest

Oil Palm

Rubber

NSE:0.78

NSE:0.71

RESULTS Simulated Flow using land cover year 2002 Daily

Monthly

0

100

200

300

400

500

600

1/1

/19

84

1/1

/19

85

1/1

/19

86

1/1

/19

87

1/1

/19

88

1/1

/19

89

1/1

/19

90

1/1

/19

91

1/1

/19

92

1/1

/19

93

1/1

/19

94

1/1

/19

95

1/1

/19

96

1/1

/19

97

1/1

/19

98

1/1

/19

99

1/1

/20

00

1/1

/20

01

1/1

/20

02

1/1

/20

03

1/1

/20

04

1/1

/20

05

1/1

/20

06

1/1

/20

07

1/1

/20

08

1/1

/20

09

1/1

/20

10

1/1

/20

11

Flo

w (

cms)

Daily

Obs Buloh Kasap SIM 2002

0

50

100

150

200

250

300

Jan

-84

Dec

-84

No

v-8

5

Oct

-86

Sep

-87

Au

g-8

8

Jul-

89

Jun

-90

May

-91

Ap

r-9

2

Mar

-93

Feb

-94

Jan

-95

Dec

-95

No

v-9

6

Oct

-97

Sep

-98

Au

g-9

9

Jul-

00

Jun

-01

May

-02

Ap

r-0

3

Mar

-04

Feb

-05

Jan

-06

Dec

-06

No

v-0

7

Oct

-08

Sep

-09

Au

g-1

0

Jul-

11

Flo

w (

cms)

Month

Obs Buloh Kasap SIM 2002

Warm-up – 1970 to 1983

Warm-up – 1970 to 1983

RESULTS Simulated Flow using land cover year 2006 Daily

Monthly

NSE: 0.77

NSE: 0.71

0

100

200

300

400

500

600

1/1

/19

84

1/1

/19

85

1/1

/19

86

1/1

/19

87

1/1

/19

88

1/1

/19

89

1/1

/19

90

1/1

/19

91

1/1

/19

92

1/1

/19

93

1/1

/19

94

1/1

/19

95

1/1

/19

96

1/1

/19

97

1/1

/19

98

1/1

/19

99

1/1

/20

00

1/1

/20

01

1/1

/20

02

1/1

/20

03

1/1

/20

04

1/1

/20

05

1/1

/20

06

1/1

/20

07

1/1

/20

08

1/1

/20

09

1/1

/20

10

1/1

/20

11

Flo

w (

cms)

Daily

Obs Buloh Kasap SIM 2006

0

50

100

150

200

250

300

Jan

-84

Dec

-84

No

v-8

5

Oct

-86

Sep

-87

Au

g-8

8

Jul-

89

Jun

-90

May

-91

Ap

r-9

2

Mar

-93

Feb

-94

Jan

-95

Dec

-95

No

v-9

6

Oct

-97

Sep

-98

Au

g-9

9

Jul-

00

Jun

-01

May

-02

Ap

r-0

3

Mar

-04

Feb

-05

Jan

-06

Dec

-06

No

v-0

7

Oct

-08

Sep

-09

Au

g-1

0

Jul-

11

Flo

w (

cms)

Month

Obs Buloh Kasap SIM 2006

Warm-up – 1970 to 1983

Warm-up – 1970 to 1983

RESULTS Simulated Flow using land cover year 2008 Daily

Monthly

NSE: 0.8

NSE: 0.72

0

100

200

300

400

500

600

1/1

/19

76

1/1

/19

77

1/1

/19

78

1/1

/19

79

1/1

/19

80

1/1

/19

81

1/1

/19

82

1/1

/19

83

1/1

/19

84

1/1

/19

85

1/1

/19

86

1/1

/19

87

1/1

/19

88

1/1

/19

89

1/1

/19

90

1/1

/19

91

1/1

/19

92

1/1

/19

93

1/1

/19

94

1/1

/19

95

1/1

/19

96

1/1

/19

97

1/1

/19

98

1/1

/19

99

1/1

/20

00

1/1

/20

01

1/1

/20

02

1/1

/20

03

1/1

/20

04

1/1

/20

05

1/1

/20

06

1/1

/20

07

1/1

/20

08

1/1

/20

09

1/1

/20

10

1/1

/20

11

Flo

w (

cms)

Daily

Obs SIM

0

50

100

150

200

250

300

Jan

-76

Mar

-77

May

-78

Jul-

79

Sep

-80

No

v-8

1

Jan

-83

Mar

-84

May

-85

Jul-

86

Sep

-87

No

v-8

8

Jan

-90

Mar

-91

May

-92

Jul-

93

Sep

-94

No

v-9

5

Jan

-97

Mar

-98

May

-99

Jul-

00

Sep

-01

No

v-0

2

Jan

-04

Mar

-05

May

-06

Jul-

07

Sep

-08

No

v-0

9

Jan

-11

Flo

w (

cms)

Month

FLOW Buloh Kasap SIM208mth2008

Warm-up – 1970 to 1983

Warm-up – 1970 to 1983

RESULTS Simulated Flow COMPARISONS for 2002, 2006 and 2008

0

100

200

300

400

500

600

1/1

/19

84

1/1

/19

85

1/1

/19

86

1/1

/19

87

1/1

/19

88

1/1

/19

89

1/1

/19

90

1/1

/19

91

1/1

/19

92

1/1

/19

93

1/1

/19

94

1/1

/19

95

1/1

/19

96

1/1

/19

97

1/1

/19

98

1/1

/19

99

1/1

/20

00

1/1

/20

01

1/1

/20

02

1/1

/20

03

1/1

/20

04

1/1

/20

05

1/1

/20

06

1/1

/20

07

1/1

/20

08

1/1

/20

09

1/1

/20

10

1/1

/20

11

Flo

w (

cms)

Daily

Obs Buloh Kasap SIM 2008 SIM 2006 SIM 2002

0

50

100

150

200

250

300

Jan

-84

No

v-8

4

Sep

-85

Jul-

86

May

-87

Mar

-88

Jan

-89

No

v-8

9

Sep

-90

Jul-

91

May

-92

Mar

-93

Jan

-94

No

v-9

4

Sep

-95

Jul-

96

May

-97

Mar

-98

Jan

-99

No

v-9

9

Sep

-00

Jul-

01

May

-02

Mar

-03

Jan

-04

No

v-0

4

Sep

-05

Jul-

06

May

-07

Mar

-08

Jan

-09

No

v-0

9

Sep

-10

Jul-

11

Flo

w (

cms)

Monthly

Obs Buloh Kasap SIM 2008 SIM 2006 SIM 2002

RESULTS Simulated Annual Flow COMPARISONS for 2002, 2006 and 2008

0

10

20

30

40

50

60

70

80

901

97

61

97

71

97

81

97

91

98

01

98

11

98

21

98

31

98

41

98

51

98

61

98

71

98

81

98

91

99

01

99

11

99

21

99

31

99

41

99

51

99

61

99

71

99

81

99

92

00

02

00

12

00

22

00

32

00

42

00

52

00

62

00

72

00

82

00

92

01

02

01

1

Flo

w (

cms)

Year

Flow Land use 2002 Flow Land use 2006 Flow Land use 2008

Conclusion.. • Vast replacement of rubber to oil palm seem to contribute

to increase in frequency and magnitude of flooding.

• Still need to check against rainfall events & more detailed subwatershed comparisons needed.

• If proven the case, stormwater management plan is necessary for even the rural oil palm plantation to prevent monsoonal flooding.

• SWAT is capable of doing hydrology in heavy-rainfall tropical monoculture (rubber, oil palm) environment.

Merci..