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Flood Induced Land Use Change Detection Using GIS

A Case Study of Kuttanad Taluk, Alappuzha, Kerala

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���Introduction

  • Recently Kerala was affected by one of the worst disasters it faced in decades. (Annual rainfall: 1701.4mm - 2394.1mm)

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  • The flood affected almost every land use class in Kerala.

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  • Land use change assessment is crucial for flood damage reduction by means of improved land use planning.

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Objectives

  • To detect land use/land cover changes in Kuttanad taluk, Alappuzha, Kerala due to flood using GIS techniques in classes such as :
    • Water bodies
    • Agriculture
    • Urban areas

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Study Area

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Materials and Methods

Input Dataset: Sentinel-2B MSIL-1C

Date of Acquisition: 20/03/2018 and 11/09/2018

Software Used: QGIS (3.2.3), ArcGIS (10.4), ESA-SNAP

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Before

After

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  • The pre-flood and post-flood image of the entire taluk was digitized and different classes were assigned.

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  • The percentage areal coverage of different classes were calculated.

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  • The change in percentage areal coverage before and after the flood was calculated

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Results & Discussions

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LU/LC CLASS

AREA IN KM2

PERCENTAGE

AGRICULTURE

195.556492

67.40511427

BARREN LAND

2.858233

0.98518602

FLOODED

11.074729

3.817277382

URBAN LAND

76.740706

26.45126226

VEGETATION

3.890989

1.341160068

Pre-Flood Percentage Area Coverage

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LU/LC CLASS

AREA IN KM2

PERCENTAGE

AGRICULTURE

16.50300212

5.769494865

BARREN LAND

3.084123951

1.078218203

FLOODED

145.2626431

50.78421896

PARTIALLY FLOODED

84.57500798

29.56765507

URBAN AREA

36.61416576

12.80041291

Post Flood Percentage Area Coverage

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Conclusion

  • Major portion of the study area was submerged under water.

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  • Approximately 92.5% of agriculture field was flooded.

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  • Around 51.5% of urban area was flooded.

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THANK YOU!