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AN ASSESSMENT OF DETECTION OF DISPARITIES OF LAND USE AND LAND COVER MAP OF KHAGRACHARI DISTRICT FROM 2013-2023

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Md. Arafatul Alam, Farin Tasnuva Dhara

GROUP 8

OUTLINES

INTRODUCTION

OBJECTIVES

STUDY AREA

MATERIALS AND METHODOLOGY

RESULTS AND DISCUSSIONS

CONCLUSION

INTRODUCTION

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• Bangladesh is one of the smallest countries in the world, with a vast population (165.2 million) and limited land areas (147,570 km²).

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• The importance of LULC classification lies on the fact that this categorization appoints land cover classes to pixels and classify them. For instance, water, metropolitan, woodland, horticulture, buildings, agriculture, and so on.

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• LULC maps of an area provide information to help users to understand the current landscape.

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• Large cities and towns use extensive land areas, which alter the natural state of land, degrade environmental integrity, fragment ecosystems and threaten biodiversity.

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• Since human activity has already caused a significant portion (>80%) of the degradation of natural resources involving land surfaces, increased population density should be carefully contemplated to ensure sustainable development that fulfills the Sustainable Development Goals.

OBJECTIVES

• To detect the change of LULC in Khagrachari district.

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• To detect the degradation of woodland and watershed areas over the years.

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• To find out the possible solutions to improve the current circumstances.

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STUDY AREA

Figure 1: Main study area comprising Khagrachari district

MATERIALS AND METHODOLOGY

Data Collection

USGS Earth Explorer

(Cloud Cover < 0-5%

Dates Selected- 01 Dec to 31 Dec

Downloaded Files- Band 1-5 & MLT File)

Figure 2: Locating the selected data area

Figure 3: Landsat data collection from USGS

Classification by QGIS

Rasters of different bands are added

Atmospheric correction is applied to the raster band layers using the SCP plugin in QGIS

Bands are clipped by mask of raster layer by using the raster conversion tool

Virtual band sets are created using the 3-2-1 and 4-3-2 RGB tool of SCP

A new ROI and Signature database scp file are then created

Usage of HCMGIS Google Satellite base-map

The classification is worked out with the SCP plugin by using classification tool under band processing unit.

Then the map is added to a new layout print

Finally the produced layout is exported as PNG

Figure 4: Addition of Khagrachari District as vector shape file

Figure 5: Clipped the bands masked by interested Khagrachari district area

Figure 6: Creation of virtual RGB band set sight

Figure 7: Supervised classification training the signature process

Figure 8: Usage of classification tool

Figure 9: Creation of virtual RGB band set sight

RESULTS AND DISCUSSIONS

• From the plotted maps, it can be detected that there were numerous small reservoirs and a vast majority of forest areas in 2013.

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• It is clear from the map of 2018 that crops and settlement areas have primarily taken over the reservoir and forest areas. Also, the river areas might be deeply eroded, and new settlement areas might be created due to increased dredging.

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• Though the watershed areas are decremented due to unethical cutting and filling, a large-scale reservoir area has suddenly been made in the southeast corner of Khagrachari.

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• However, this area, along with the main river areas, has primarily decreased in 2023 due to increased sedimentation, continuous riverbank erosion, and the creation of newly excavated crop areas.

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• Compared with 2013, the watershed areas were significantly reduced in these ten years, and freshly generated crop areas essentially took over these areas.

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• The significant regression of the watershed areas would adversely impact the overall ecosystem, as wildlife largely depends on the balance between woodlands and watersheds, so destroying these areas will eradicate the equilibrium.

Figure 10: LULC Map of Khagrachari district in the year 2013

Figure 11: LULC Map of Khagrachari district in the year 2018

Figure 11: LULC Map of Khagrachari district in the year 2023

CONCLUSION

• Overall, the world population is increasing day by day. So, it might be impossible to impose strict conservation laws, as the more people grow, the more utilities will be required to fulfil their basic needs.

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• However, to avoid the worldwide natural calamities, the conservation of forest areas and wildlife must be stricter, and necessary steps must be taken regarding reforestation.

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• The changes in the water body may be caused by drought, climate change, or a lack of rainfall. However, it should not be destroyed due to the creation of settlements and other human needs.

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• Whatever erosion has already done to the overall landscape has already gone, but it is time to conserve the wildlife. If we can all work together, we can protect the balance of the ecosystem.