IMPACT OF LAND COVER CHANGE TO WATER QUALITY AND AQUACULTURE ACTIVITY IN

TONDANO LAKE

United Nations/Pakistan International Workshop on Integrated use of Space Technologies or Food and Water Security

Islamabad, 11-15 March 2013

Bambang Trisakti and Tatik KartikaRemote Sensing Application Center

Indonesia National Institute of Aeronautics and Space

INTRODUCTION

Indonesia has around 840 big lakes and 735 small lake which supply 72% of total water surface in the country. The lakes has functions for providing drinking water, irrigation, power generation, aquaculture, and tourism (MOE)

Indonesia government has established a National Program for Lake Rescue 2010-2014 :

First Lake Conference in Bali, 13 August 2009

Second Lake Conference in Semarang, 13-14 October 2011

15 lakes are the priority of environmental crisis to resolve. Signed by 9 ministers

to confirm the 15 lakes becoming the priority lakes of 2010-2014 periods.

Severe ecosystem degradation happened in many lakes high sedimentation, land conversion in watershed, water pollution etc., that disturbed the functions of the lake.

INTRODUCTION

Assessment criteria of designated priority lakes are :

1. Lake damage: the level of sedimentation, pollution, eutrophication, highly reducing quality and quantity of water.

2. Lake utilization : hydropower plant (PLTA), agriculture, fisheries (aquaculture/floating cage), usable water, religious and culture values, tourism (including lake uniqueness, accessibility, amenity (infrastructure and society condition)

3. Local government’s and the society’s commitment to wisely manage the lakes (master plan, local regulation (perda), managing committee).

4. Strategic lake : lakes featuring strategic functions of national interest

5. Biodiversity (including: endemic fish species, aves and vegetation).

6. C carbon urgency (the challenge against global climate change)

15 PRIORITY LAKES IN INDONESIA

1. Toba Lake (North Sumatera)

2. Maninjau lake

3. Singkarak Lake (West Sumatera)

4. Kerinci Lake (Jambi)

5. Rawa Danau (Banten)

6. Rawapening Lake (Central Java)

7. Batur Lake (Bali)

8. Tempe Lake

9. Matano lake (South Sulawesi)

10. Poso Lake (Central Sulawesi)

11. Tondano Lake (North Sulawesi)

12. Limboto Lake (Gorontalo)

13. Sentarum (West Kalimantan)

14. Cascade Mahakam Lake (East Kalimantan)

15. Sentani Lake (Papua)

Tondano Lake (North Sulawesi)

STUDY AREA (TONDANO LAKE)

It is located in north Sulawesi province, and it is one of the priority lakes

Danau Tondano

The lake has environmental problems related to land conversion, high sedimentation, water quality and fast growing of aquatic plant

87 percent of fish production in freshwater of this province were fulfilled from Tondano lake

The lake have been utilized for hydroelectric power plant, freshwater fish, drinking water, irrigation, eco tourism and flood control

PURPOSES

1. To utilize remote sensing satellite data for supporting Indonesia government program for lake rescue

2. To monitor the land cover change in watershed and lake quality change including lake area, aquatic plant distribution, water quality (Total Suspended Solid and water transparency) using multi temporal data.

DATA USED

Satellite Data Landsat TM/ETM+ (Spatial 30 m) and SPOT-4 (spatial 20 m) for period

1990-2011 SRTM DEMver. 4.1 (Spatial resolution 90 m) High resolution IKONOS (Spatial 1 m) in 2003 and 2011.

Others data Topography map 1: 50.000 scale Field survey (land cover and water quality)

Landsat: 30 m SPOT: 20 m IKONOS: 1 m SRTM: 90 m

METODOLOGY

Landsat and SPOT data

Orthorectification and

radiometric

Data Normalization

Map, SRTM

Land cover RGB

composite

Lake area Aquatic veg.

distribution

Field

measurement

AlgorithmWater quality

TSS and water

transparency

Multi temporal analysis

Result

• Sun correction

• atmospheric correction

Spectrometer

measurement

NORMALIZATION FOR LANDSAT – SPOT 4 DATA

Normalization were conducted for each band to standardize different satellite

sensor/different spectral range (Landsat and SPOT)

RESULT OF DATA NORMALIZATION

Data relatively has same value for the same object

TOPOGRAFY AND WATERSHED BOUNDARY

-27 m

0 m

Kontur Interval 2 m

DanauTondano

Sumber: peta RBI dan Peta bathimetri tondano

Sumber: DEM dan Peta RBI

SRTM DEM was fused with topography map

using DEM integration method

3D of Tondano lake`s watershed

Watershed boundary generation

LAND COVER OF TONDANO LAKE IN 1990

Water body

Forest

Plantation

Mixied Plantation

Dry agriculture

Open land

Urban

Swamp

Paddy field

Administration boundary

Legend

Shrubs/bushes

Classification by visual interpretation, and verified using high resolution

data and field measurement

Water body

Forest

Plantation

Mixed Plantation

Dry agriculture

Open land

Urban

Swamp

Paddy field

Shrubs/bushes

Administration boundary

Legend

Land cover of Tondano Lake in 2003

LAND COVER OF TONDANO LAKE IN 2003

Water body

Forest

Plantation

Mixed Plantation

Dry agriculture

Open land

Urban

Swamp

Paddy field

Administration boundary

Legend

Land cover of Tondano Lake in 2011

LAND COVER OF TONDANO LAKE IN 2011

Shrubs/bushes

LAND COVER CHANGE IN PERIODE 1990-2011

Signification change of land cover in Tondano Lake`s

watershed in period 1990-2011

LAKE AREA AND AQUATIC PLANTS DISTRIBUTION

Aquatic plants

Delineation lake

area including

aquatic plant

Previous research:

RED : NIR + SWIR

GREEN : NIR

BLUE : NIR - RED

LAKE AND AQUATIC PLANTS AREA CHANGE

1990 2000 2003 2011

Area (ha)

Aquatic plants

(Water Hyacinth)

Lake

Information

2003

1990

2011

Increase

LAKE AND AQUATIC PLANTS AREA CHANGE

1990 2000 2003 2011

Area (ha)

Increase

Area in 2011

(ha)

AQUACULTURE IN TONDANO LAKE

Citra IKONOS 2003 (1 m) Citra Landsat 2003 (30 m)

Possible for wide cages, but difficult for small cages

Can be easily indentified

Aquaculture in Tondano lake

Used IKONOS data to identify and map Aquaculture area in Tondano lake

AQUACULTURE AREA IN TONDANO LAKE

2003 2011

Aquaculture area increased almost 2 times

AQUA CULTURE AREA IN TONDANO LAKE

2003

2011

Aqua culture areaAquatic plants area

2003

2011

Aquatic plants covered cages, and disturb the aquaculture activity

FIELD MEASUREMENT FOR WATER QUALITY

Spectrometer measurement

Sampling for TSS Water transparency measurement

Other water quality parameters measurement

Develop water quality algorithm using bio-optical model

SPECTROMETER MEASUREMENT RESULTS

0

5

10

15

20

25

30

35

40

45

50

400 500 600 700 800 900

S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

S11

S12

S13

S14

S15

Wavelength( m)

Reflecta

nce (%

)

0

5

10

15

20

25

30

35

40

45

480 560 660 840

S1

S2

S3

S4

S5

S6

S7

S8

S9

S10

S11

S12

S13

S14

S15

Wavelength( m)

Refl

ecta

nce

Spectral reflectance of water in different TSS concentration (less than 20 mg/l)

Spectral respond of Landsat sensor b1-4

Calibrated spectral reflectance in Landsat band 1 - 4

Band 1 – 3 has capability to differ TSS concentration (low concentration)

Band 4 is almost absorbed by water

CORRELATION WITH FIELD MEASUREMENT

Band2/band 1 (-)

Gro

un

d m

ea

su

rem

en

t T

SS

(m

g/l

)

y = 14.785x - 15.08R² = 0.7198

0

5

10

15

20

0.0 0.5 1.0 1.5 2.0 2.5

y = 1.8317e0.162x

R2 = 0.8367

0

10

20

30

40

50

60

0 5 10 15 20

y = -14.348x + 291.84

R2 = 0.8365

0

50

100

150

200

250

300

0 5 10 15 20

TSM (mg/l)

Tu

rbid

ity (N

TU

)

TSM (mg/l)

Ke

ce

rah

an

(cm

)

Ground measurement TSS (mg/l)Gro

un

d m

ea

su

rem

en

t t

ran

sp

are

nc

y (c

m)

Total Suspended Solid (TSS)

Water Transparency

Best correlation comparing to other ratio bands

TSS IN PERIOD 1990-2011

1990 2001 2003 2011

High TSS concentrated along shoreline of the lake,

and the value of TSS ranged from 0 – 40 mg/l

They were lower comparing to Criteria of water quality

standard (Government regulation. No.82, 2001) water

drinking, aquaculture and tourism activities

WATER TRANSPARENCY IN PERIODE 1990-2011

1990 2001 2003 2011

Water transparency for aquaculture ranges 1-2 m

(Mantau et al., 2004)

The results were almost better comparing to the range,

except along shoreline in the western part of the lake

which has low transparency.

CONCLUSION

1. Remote sensing data can be utilized to monitor the change in watershed and lake quality

2. It is found that land conversion happened in watershed of the lake (forest decreased, urban and agricultural area increased). The forest area in 2011 was remained 6.5 % from the total watershed area.

3. Lake area was relatively same, but aquatic plant significantly increased, which disrupted the aquaculture activity

4. Water quality slightly decreased along period 1990-2011, but it was still fulfilled the standard for aquaculture.

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