Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Abstract

Urbanization has become a hot issue in context of environmental and socio-political scenarios which is being addressed at every forum internationally. The classification results of Islamabad showed that the total area of Islamabad was about 899.56 sq.km. The area wise percentages of various landuse features remained very diverse in the period from 2000 to 2020. The area of barren land was highest in the year 2000 that was around 63 % of total LULC. Barren land faced major shift and the area reduced from 63 % to 40% in 2020. The built-up area has increased rapidly over the course of 20 years which was 4% in 2000 and increased up to 36% in 2020, which is alarming for any country. This study reveals that the settlement area has increased by 54 percent between 2000 and 2020. The geological map of study site is showing that Islamabad is located on the fault lines which are dangerous and the earthquake may hit this area any time which leads to huge disaster in coming future therefore this region is unsuitable for megastructures even for setting up small localities. The drainage network is showing that most of water channels were found in SE direction clearly narrating that the trend of population was also in the same direction. This resemblance signifies that people rush toward water channels to manage their daily routine in a better way. Slope map is showing that there were gentle slopes in southern parts of study site while steep slopes were observed in extreme northSteep slopes are considered unsuitable for living therefore about 99% of urban settlements were found toward gentle slopes. Hazard map is showing that the NE of study site is dangerous for human settlements because this area was found prone to earthquakes. Luckily most of urban settlements were not found on this site and it is recommended the land authority must not approve any new settlement/mega project on this area. It is recommended that government must take strict action on emergency footings to demarcate urban lands so that the agricultural lands must remain intact to save flora and fauna of the city and to get sustainable agricultural developments.

Keywords: DEMSlopearthquakeLULCUrban transformationForestChange Detection.

Introduction

Urbanization has become a hot issue in context of environmental and socio-political scenarios which is being addressed at every forum internationally [1]. It is a major phenomenon and a reality not only for developing but for developed countriesLand Use Land Cover Classification (LULCC) played a major role in affecting the environment and making changes in life’s socio-economic spheres. Unplanned expansion of prearranged sectors and loss of natural forest cover could be dangerous for a planned city like Islamabad. It can cause a lot of conflicts and devastate the city’s law and order situations if the situation remained unrestrained (e.g., law and order situation in Karachi). Expansion should be uniform and organized otherwise it can result in improper and uneven distribution of resources [2].

LULC changes are basically alteration of the land’s surface according to the socio-economic and cultural needs of residents that brings about these changes [3]Moreover, LULCC is defined as the utilization of a land, modifications on earthen floor and usage of land for different activities [2,4,5]. Since the prehistoric times, it is seen that humans have evolved with a quest of better living conditions and tried to introduce better lifestyles [6]. Since origin, humans have been evolved physically and physiologically, as well as mentally and functionally [7]. They have become socio-economically and culturally changed entities. Humans have become habitual of evolving according to their basic amenities [8]. Therefore, the human activities are involved in LULCC in any habitable region of the worldHumans have become civilized and have modified their living standards dramatically.

Changes in the structures of houses vary individual to individual, household to household and community to community according to environment and terrain [9]. Increase in population is the main cause of urbanization and congestion of residential areasThe mega cities are considered the main origin of socio-economic development which caused to emerge a number of issues like biodiversity, environmental degradation, resource consumption, implementation of law and order and provision of basic facilities to the general public [10]. The need of observation of these changes arose because human life is affected directly and indirectly by these changes [11]. These observations of change-detection were originated from the needs which urged the respective authorities to think about the change detection strategies. But the factors which urged humans to bring changes in the usage of land is another debate [12, 13].

It is important to see the global trends of LULC change analysis as well as the factors that lead to these maneuverings of the land. But inducing and deducing forces are more important than the change itself.  It is observed that the forces behind different types of migrations and settlements are mainly in form of migrations, disasters, movements, and climatic conditions as well as an important factor is the availability of the resources [14]Population increase is basically a key factor behind any change in any region of the world [15,5]. Thus, the recent migration trend of masses towards developed cities in search of basic needs of life is very common around the world. It is the main reason of extensive urbanization [16]. The fate of a land or the regional utilization of an area is determined by different social, economic, environmental or climatic and cultural factors [17]. Technology has facilitated scientists and researchers to examine the change detection using multispectral images with highly precise instruments providing accurate readings [1819].

Geographic Information System (GIS) and Remote Sensing (RS) are the two broader fields which provide the researchers with the basic framework for assessment of changes in land use [20]. Remote sensing has enhanced both the spatial and temporal resolutions many folds and now it has become easy to estimate the changes in landuse with a temporal window of less than a day accurately [2122, 23242526].

LULC changes involve both natural and man-made features [27]. Urban land use changes are affected by many dynamic forces that can be switched by ecological and socio-economic variables. The worldwide momentum of mass ecological change and maintenance issues explains the importance of LULC change diversity in various parts of the world [28]Land cover can be affected by both the water permeation and overflow after rainfall, while land cover’s permeability can disturb the rates of evaporation. Land cover determines water regulation, which drifts both above and below the ground [2922]. For example, canopy interruption can reduce rainfall’s influence on the ground, by reducing soil erosion, holding roots in place and by absorption of water. In the absence of vegetative cover on the ground, the process of soil erosion impacts the productivity of all natural, agricultural, forest, and rangeland ecosystems, seriously decreasing water availability, energy, and biodiversity throughout the world [23].

A multi-dimensional study to examine changes in landuse were carried out and its quality was examined throughout China’s Yellow River Delta. This research concentrates on the qualitative study of land use and the objective of the study was to explore a global perspective and deduce a better idea for sustainable development. In this research, there is a link between how the changing land qualities are correlated to human activities and to which extent these changes occur. Land qualities refer to the ability of productiveness of land [3031,32,33,34,35,36,37].

The goal of this research was to examine the spatio-temporal changes in LULC of Islamabad by considering various parameters including topography, drainage pattern, slop and geological structures.

Material and Methods.

Investigation site.

Islamabad is the capital of Pakistan located at 33° 49′ N latitude and 72° 24′ longitudes. Islamabad’s altitude ranges from 457 m to 610 m from sea level. Relative location of Islamabad is along the fringe of North-East of both Rawalpindi as well as Potohar Plateau. Historically it is evident that, Islamabad remained a cross way between KPK and Punjab through Margalla Hills. The study site is mapped in Figure 1.

Cityscape and Zoning

Islamabad was designed to comply with the Master Plan of the Greek City having 8 main zones including administrative, diplomatic, residential, educational, industrial, commercial, rural and green areas. Each zone is divided into different sectors which are named and valued on development basis. The detail linked to each zone is mentioned in table 1.

Table 1. Classification of Islamabad area in Zones
Zones Area (acres) Area (Sq. Km.)
I 54,958.25 221.5
II 9,804.92 40
III 50,393.01 203.9
IV 69,814.35 283
V 39,029.45 157.1

 

Figure 1 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 1. Study Site

Climate

Islamabad is a humid subtropical region having humid summer and the monsoon region following winters which is cool. The average climatic characteristics of Islamabad are given in Table 2,

Table 2. Climatic Data of Islamabad
Seasons of Islamabad High (Avg.) Low (Avg.)
Oct-Mar (Winters) 15.2 °C 1.4 °C
Apr-Sept (Summers) 36.1 °C 22.3 °C
Year Average 25.65 °C 11.85 °C
Average Humidity 56%
Average Rainfall 1144 millimeters

Remotely sensing datasets provide critical sustainability assessment support. In this research three satellite images of Landsat have been downloaded from United State Geological Survey (USGS) website. The detail of Landsat images is mentioned in Table 3 as below,

Table 3. Characteristics of acquired satellite images

Sr No Class Name Date of Acquisition Resolution
1 Landsat 7 May 11, 2000  

30 m

2 Landsat 8 March 30, 2013
3 Landsat 8 June 12, 2020

Pre-Processing of Satellite Images

Pre-processing of the image usually means preparing a satellite image for further processing.  The steps involved in preprocessing which we performed are as follow,

  • Layer Stacking (For binding various bands of satellite)
  • Extraction of Area of Interest (AOI) (For extraction of area of interest)
  • Geometric corrections (To rectify the geometry of landuse features)

The major landuse features are mentioned in Table 4

Table 4. Classes delineated based on supervised classification

Sr#. Class Name Description
1 Built-Up Area Residential, commercial, industrial, transportation, roads.
2 Green Cover Mixed forest lands, Crop fields and fallow lands
3 Barren Land Landuse exposed to soil
4 Water Body River, open water, lakes, ponds, and reservoirs

Supervised Classification

The supervised classification was used to classify an image with the spectral signatures obtained from samples of training sites. Training samples were selected randomly.  Training samples are basic inputs to decide which class inherit each pixel throughout the image.

Digital Elevation Model (DEM)

We used a DEM of 30m resolution of Shutter Radar Topographic Mission (SRTM) for estimation of soil, slope, drainage and hazard maps to examine the impact of topographic variation on landuse patterns. The flow of study is mapped in Figure 2,

Result and discussion.

Results show rapid growth of urban areas over the last two decades.

Land Use / Land Cover Image of Islamabad (2000)

Figure 3. is the classified image of Islamabad of the year 2000. This satellite image was classified in ArcGIS through supervised classification and mapped landuse classes in dedicated colors e.g., red color for built-up area, green color to vegetation and blue color has been assigned to water body. Pie chart represent the results acquired through image classification. The area covered with Barren Land is 63% which is the highest among the others classes like the green cover is 32 %, built-up area is 4 % and water body covered the minimum area which is 1%.

Figure 2 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 2. Flow of study

Figure 3 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 3. Landuse/Landcover Image of Islamabad (2000)

Land Use / Land Cover Image of Islamabad (2013)

Figure 4 is the classified map of Islamabad of the year 2013. The figure is showing an immense growth in built up area. The year 2013 can be marked as a year where the growth of the urban city picked up the pace with the rest of the world. The results of image classification show that the area covered with barren land was 67% which is the highest among the others classes like the green cover was 19%, built-up area was 14% and water body covered the minimum area which was 1%. The data in pie chart is conveying a visual understanding of percentage of each class in 2013.

Figure 4 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 4. Landuse/Landcover Image of Islamabad (2013)

Land Use / Land Cover Image of Islamabad (2020)

Figure 5 is the classified map of Islamabad of the year 2020 which is clearly showing that maximum change in the built-up area is observed. The results of image classification show that the area covered with barren land is 40% which is the highest among the others classes like the green covered which is 24%, built-up area is 36% and water body covered the minimum area which is 1%. The data in pie chart is showing a visual understanding of percentage of each class in 2020.

Figure 5 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 5. Landuse/Landcover Image of Islamabad (2020)

Comparative Analysis of LULC (2000, 2013 and 2020)

The comparative analysis of LULC in Islamabad was done by using change detection map which comprised of classified images of Islamabad and used to extract information of dynamic changes in the city from 2000 to 2013 and from 2013 to 2020 shown in Figure 6. Comparative study of three years 2000, 2013 and 2020 (figure 7) has shown abrupt changes in built-up area which is increased 720 % due to newly built residential societies and infrastructure being built in the middle and western side of Islamabad due to better opportunities and better facilities with increase in the population density. Barren land is approximately decreased about 36 % in 19 years mainly from 2013 to 2020, the biggest change was the transformation of most barren land to built-up areas and continued to expand. In this research, forest cover was declined by 25 % during last 19 years, i.e. between 2000 and 2020. The massive damage to forests was due to wildfire in summer due to rise in temperature up to 45 °C. Wildfire is one of the main causes of forest loss to sparse vegetation. Figure 7 is showing the comparative analysis of LULC with overall change in landuse.

Figure 6 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 6. Change Detection Map of Islamabad

Figure 7 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 7. Comparative Analysis of LULC

Analysis of Built-up Area Extent:

The classification results of Islamabad showed that the total area of Islamabad was about 899.56 sq.km. The area wise percentages of various landuse features remained very diverse in the period from 2000 to 2020. The area of barren land was highest in the year 2000 that was around 63 % of total LULC. Barren land faced major shift and the area reduced from 63 % to 40% in 2020. The built-up area has increased rapidly over the course of 20 years which was 4% in 2000 and increased up to 36% in 2020, which is alarming for any country. This study reveals that the settlement area has increased by 54 percent between 2000 and 2020 (Table 4). It was a dramatic change, with incredible pressure on unbuilt surfaces and on agricultural lands. The expansion in urban area was due to rapid construction of residential, industrial, commercial units and road networks, as well as port, recreational pavements and other impenetrable surfaces combined which led to the continuing expansion of constructed areas of the city.

During this time, the change in urban landuse can be related to population growth and industrial development. Biodiversity loss and decreasing environmental conditions are the result of rapid urbanization. Urban settlements are dangerous for the natural habitat because road networks, recreational infrastructure, buildings, schools and colleges, have provided open ended places which has forced natural habitat to settle themselves at safer places.

Results show that the forests, mainly found in 2000, on the western margins, were fully converted into sparse vegetation by 2020 due to several reasons, such as stone quarries, agricultural practices to cater the food demands of increasing population, timber cutting for the consumption of fuel by the villagers, and factual cement industry which borders the western periphery and therefore created vacant areas. Figure 8 (C) represents that built-up expansion shifted towards south eastern and western side of Islamabad city.

Figure 8 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 8. Analysis of built-up area

Topographical analysis

Figure 9 (A) DEM represents the 3D shape of terrain and also used as input to extract stream network. (B) Flow direction was computed from DEM (C) the flow was accumulated and the streams are defined (D) Major drainage network was extracted from the flow accumulation (E) Catchment area of watershed was delineated through point of origin. (F) watershed and drainage stream network, reflects the structural arrangement of rocks, where stream bends represent the existence of hard/soft rocks beneath the earth’s surface that drive water in a complex way like neural network in human body. (G) Slop was extracted from DEM for evaluating the factors behind the urban expansion. (H) soil data is very important factor for land-use and land cover variation. (I) earthquake zones are also important for the evaluating the risk assessment as the Islamabad lays on the fault lines therefore it is not considered comparatively safe.

The geological map of study site is in Figure 9(F) which show that Islamabad is located on the fault lines which are dangerous and the earthquake may hit this area any time which leads to huge disaster in coming future therefore this region is unsuitable for megastructures even for setting up small localities.

The Figure 9 (D) is showing that most of water channels were found in SE direction and if we compare it with Figure 8 (c), it shows that the trend of population was also in the same direction. This resemblance signifies that people rush toward water channels to manage their daily routine in a better way.

Figure 9 (G) is showing that there were gentle slopes in southern parts of study site while steep slopes were observed in extreme north. Steep slopes are considered unsuitable for living therefore about 99% of urban settlements were found toward gentle slopes.

Figure 9(H) is showing that the NE of study site is dangerous for human settlements because this area was found prone to earthquakes. Luckily most of urban settlements were not found on this site and it is recommended the land authority must not approve any new settlement/mega project on this area.

Conclusion.

This study is unique in context of examining the LULCC by incorporation local topography including fault lines, drainage network and hazardous areas. It is observed that urban growth is very fast and eating up not only barren lands but also very fertile agricultural lands. A specie is restricting with certain ecological conditions which may not be grown at odd places and if an artificial ecological condition is created at odd places, the outcomes may not be economically sound. Therefore, it is recommended that government must take strict action on emergency footings to demarcate urban lands so that the agricultural lands must remain intact to save flora and fauna of the city and to get sustainable agricultural developments.

Abstract

Urbanization has become a hot issue in context of environmental and socio-political scenarios which is being addressed at every forum internationally. The classification results of Islamabad showed that the total area of Islamabad was about 899.56 sq.km. The area wise percentages of various landuse features remained very diverse in the period from 2000 to 2020. The area of barren land was highest in the year 2000 that was around 63 % of total LULC. Barren land faced major shift and the area reduced from 63 % to 40% in 2020. The built-up area has increased rapidly over the course of 20 years which was 4% in 2000 and increased up to 36% in 2020, which is alarming for any country. This study reveals that the settlement area has increased by 54 percent between 2000 and 2020. The geological map of study site is showing that Islamabad is located on the fault lines which are dangerous and the earthquake may hit this area any time which leads to huge disaster in coming future therefore this region is unsuitable for megastructures even for setting up small localities. The drainage network is showing that most of water channels were found in SE direction clearly narrating that the trend of population was also in the same direction. This resemblance signifies that people rush toward water channels to manage their daily routine in a better way. Slope map is showing that there were gentle slopes in southern parts of study site while steep slopes were observed in extreme northSteep slopes are considered unsuitable for living therefore about 99% of urban settlements were found toward gentle slopes. Hazard map is showing that the NE of study site is dangerous for human settlements because this area was found prone to earthquakes. Luckily most of urban settlements were not found on this site and it is recommended the land authority must not approve any new settlement/mega project on this area. It is recommended that government must take strict action on emergency footings to demarcate urban lands so that the agricultural lands must remain intact to save flora and fauna of the city and to get sustainable agricultural developments.

Keywords: DEMSlopearthquakeLULCUrban transformationForestChange Detection.

Introduction

Urbanization has become a hot issue in context of environmental and socio-political scenarios which is being addressed at every forum internationally [1]. It is a major phenomenon and a reality not only for developing but for developed countriesLand Use Land Cover Classification (LULCC) played a major role in affecting the environment and making changes in life's socio-economic spheres. Unplanned expansion of prearranged sectors and loss of natural forest cover could be dangerous for a planned city like Islamabad. It can cause a lot of conflicts and devastate the city's law and order situations if the situation remained unrestrained (e.g., law and order situation in Karachi). Expansion should be uniform and organized otherwise it can result in improper and uneven distribution of resources [2].

LULC changes are basically alteration of the land's surface according to the socio-economic and cultural needs of residents that brings about these changes [3]Moreover, LULCC is defined as the utilization of a land, modifications on earthen floor and usage of land for different activities [2,4,5]. Since the prehistoric times, it is seen that humans have evolved with a quest of better living conditions and tried to introduce better lifestyles [6]. Since origin, humans have been evolved physically and physiologically, as well as mentally and functionally [7]. They have become socio-economically and culturally changed entities. Humans have become habitual of evolving according to their basic amenities [8]. Therefore, the human activities are involved in LULCC in any habitable region of the worldHumans have become civilized and have modified their living standards dramatically.

Changes in the structures of houses vary individual to individual, household to household and community to community according to environment and terrain [9]. Increase in population is the main cause of urbanization and congestion of residential areasThe mega cities are considered the main origin of socio-economic development which caused to emerge a number of issues like biodiversity, environmental degradation, resource consumption, implementation of law and order and provision of basic facilities to the general public [10]. The need of observation of these changes arose because human life is affected directly and indirectly by these changes [11]. These observations of change-detection were originated from the needs which urged the respective authorities to think about the change detection strategies. But the factors which urged humans to bring changes in the usage of land is another debate [12, 13].

It is important to see the global trends of LULC change analysis as well as the factors that lead to these maneuverings of the land. But inducing and deducing forces are more important than the change itself.  It is observed that the forces behind different types of migrations and settlements are mainly in form of migrations, disasters, movements, and climatic conditions as well as an important factor is the availability of the resources [14]Population increase is basically a key factor behind any change in any region of the world [15,5]. Thus, the recent migration trend of masses towards developed cities in search of basic needs of life is very common around the world. It is the main reason of extensive urbanization [16]. The fate of a land or the regional utilization of an area is determined by different social, economic, environmental or climatic and cultural factors [17]. Technology has facilitated scientists and researchers to examine the change detection using multispectral images with highly precise instruments providing accurate readings [1819].

Geographic Information System (GIS) and Remote Sensing (RS) are the two broader fields which provide the researchers with the basic framework for assessment of changes in land use [20]. Remote sensing has enhanced both the spatial and temporal resolutions many folds and now it has become easy to estimate the changes in landuse with a temporal window of less than a day accurately [2122, 23242526].

LULC changes involve both natural and man-made features [27]. Urban land use changes are affected by many dynamic forces that can be switched by ecological and socio-economic variables. The worldwide momentum of mass ecological change and maintenance issues explains the importance of LULC change diversity in various parts of the world [28]Land cover can be affected by both the water permeation and overflow after rainfall, while land cover's permeability can disturb the rates of evaporation. Land cover determines water regulation, which drifts both above and below the ground [2922]. For example, canopy interruption can reduce rainfall's influence on the ground, by reducing soil erosion, holding roots in place and by absorption of water. In the absence of vegetative cover on the ground, the process of soil erosion impacts the productivity of all natural, agricultural, forest, and rangeland ecosystems, seriously decreasing water availability, energy, and biodiversity throughout the world [23].

A multi-dimensional study to examine changes in landuse were carried out and its quality was examined throughout China's Yellow River Delta. This research concentrates on the qualitative study of land use and the objective of the study was to explore a global perspective and deduce a better idea for sustainable development. In this research, there is a link between how the changing land qualities are correlated to human activities and to which extent these changes occur. Land qualities refer to the ability of productiveness of land [3031,32,33,34,35,36,37].

The goal of this research was to examine the spatio-temporal changes in LULC of Islamabad by considering various parameters including topography, drainage pattern, slop and geological structures.

Material and Methods.

Investigation site.

Islamabad is the capital of Pakistan located at 33° 49' N latitude and 72° 24' longitudes. Islamabad’s altitude ranges from 457 m to 610 m from sea level. Relative location of Islamabad is along the fringe of North-East of both Rawalpindi as well as Potohar Plateau. Historically it is evident that, Islamabad remained a cross way between KPK and Punjab through Margalla Hills. The study site is mapped in Figure 1.

Cityscape and Zoning

Islamabad was designed to comply with the Master Plan of the Greek City having 8 main zones including administrative, diplomatic, residential, educational, industrial, commercial, rural and green areas. Each zone is divided into different sectors which are named and valued on development basis. The detail linked to each zone is mentioned in table 1.

Table 1. Classification of Islamabad area in Zones
Zones Area (acres) Area (Sq. Km.)
I 54,958.25 221.5
II 9,804.92 40
III 50,393.01 203.9
IV 69,814.35 283
V 39,029.45 157.1

 

Figure 1 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 1. Study Site

Climate

Islamabad is a humid subtropical region having humid summer and the monsoon region following winters which is cool. The average climatic characteristics of Islamabad are given in Table 2,

Table 2. Climatic Data of Islamabad
Seasons of Islamabad High (Avg.) Low (Avg.)
Oct-Mar (Winters) 15.2 °C 1.4 °C
Apr-Sept (Summers) 36.1 °C 22.3 °C
Year Average 25.65 °C 11.85 °C
Average Humidity 56%
Average Rainfall 1144 millimeters

Remotely sensing datasets provide critical sustainability assessment support. In this research three satellite images of Landsat have been downloaded from United State Geological Survey (USGS) website. The detail of Landsat images is mentioned in Table 3 as below,

Table 3. Characteristics of acquired satellite images

Sr No Class Name Date of Acquisition Resolution
1 Landsat 7 May 11, 2000  

30 m

2 Landsat 8 March 30, 2013
3 Landsat 8 June 12, 2020

Pre-Processing of Satellite Images

Pre-processing of the image usually means preparing a satellite image for further processing.  The steps involved in preprocessing which we performed are as follow,

  • Layer Stacking (For binding various bands of satellite)
  • Extraction of Area of Interest (AOI) (For extraction of area of interest)
  • Geometric corrections (To rectify the geometry of landuse features)

The major landuse features are mentioned in Table 4

Table 4. Classes delineated based on supervised classification

Sr#. Class Name Description
1 Built-Up Area Residential, commercial, industrial, transportation, roads.
2 Green Cover Mixed forest lands, Crop fields and fallow lands
3 Barren Land Landuse exposed to soil
4 Water Body River, open water, lakes, ponds, and reservoirs

Supervised Classification

The supervised classification was used to classify an image with the spectral signatures obtained from samples of training sites. Training samples were selected randomly.  Training samples are basic inputs to decide which class inherit each pixel throughout the image.

Digital Elevation Model (DEM)

We used a DEM of 30m resolution of Shutter Radar Topographic Mission (SRTM) for estimation of soil, slope, drainage and hazard maps to examine the impact of topographic variation on landuse patterns. The flow of study is mapped in Figure 2,

Result and discussion.

Results show rapid growth of urban areas over the last two decades.

Land Use / Land Cover Image of Islamabad (2000)

Figure 3. is the classified image of Islamabad of the year 2000. This satellite image was classified in ArcGIS through supervised classification and mapped landuse classes in dedicated colors e.g., red color for built-up area, green color to vegetation and blue color has been assigned to water body. Pie chart represent the results acquired through image classification. The area covered with Barren Land is 63% which is the highest among the others classes like the green cover is 32 %, built-up area is 4 % and water body covered the minimum area which is 1%.

Figure 2 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 2. Flow of study

Figure 3 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 3. Landuse/Landcover Image of Islamabad (2000)

Land Use / Land Cover Image of Islamabad (2013)

Figure 4 is the classified map of Islamabad of the year 2013. The figure is showing an immense growth in built up area. The year 2013 can be marked as a year where the growth of the urban city picked up the pace with the rest of the world. The results of image classification show that the area covered with barren land was 67% which is the highest among the others classes like the green cover was 19%, built-up area was 14% and water body covered the minimum area which was 1%. The data in pie chart is conveying a visual understanding of percentage of each class in 2013.

Figure 4 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 4. Landuse/Landcover Image of Islamabad (2013)

Land Use / Land Cover Image of Islamabad (2020)

Figure 5 is the classified map of Islamabad of the year 2020 which is clearly showing that maximum change in the built-up area is observed. The results of image classification show that the area covered with barren land is 40% which is the highest among the others classes like the green covered which is 24%, built-up area is 36% and water body covered the minimum area which is 1%. The data in pie chart is showing a visual understanding of percentage of each class in 2020.

Figure 5 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 5. Landuse/Landcover Image of Islamabad (2020)

Comparative Analysis of LULC (2000, 2013 and 2020)

The comparative analysis of LULC in Islamabad was done by using change detection map which comprised of classified images of Islamabad and used to extract information of dynamic changes in the city from 2000 to 2013 and from 2013 to 2020 shown in Figure 6. Comparative study of three years 2000, 2013 and 2020 (figure 7) has shown abrupt changes in built-up area which is increased 720 % due to newly built residential societies and infrastructure being built in the middle and western side of Islamabad due to better opportunities and better facilities with increase in the population density. Barren land is approximately decreased about 36 % in 19 years mainly from 2013 to 2020, the biggest change was the transformation of most barren land to built-up areas and continued to expand. In this research, forest cover was declined by 25 % during last 19 years, i.e. between 2000 and 2020. The massive damage to forests was due to wildfire in summer due to rise in temperature up to 45 °C. Wildfire is one of the main causes of forest loss to sparse vegetation. Figure 7 is showing the comparative analysis of LULC with overall change in landuse.

Figure 6 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 6. Change Detection Map of Islamabad

Figure 7 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 7. Comparative Analysis of LULC

Analysis of Built-up Area Extent:

The classification results of Islamabad showed that the total area of Islamabad was about 899.56 sq.km. The area wise percentages of various landuse features remained very diverse in the period from 2000 to 2020. The area of barren land was highest in the year 2000 that was around 63 % of total LULC. Barren land faced major shift and the area reduced from 63 % to 40% in 2020. The built-up area has increased rapidly over the course of 20 years which was 4% in 2000 and increased up to 36% in 2020, which is alarming for any country. This study reveals that the settlement area has increased by 54 percent between 2000 and 2020 (Table 4). It was a dramatic change, with incredible pressure on unbuilt surfaces and on agricultural lands. The expansion in urban area was due to rapid construction of residential, industrial, commercial units and road networks, as well as port, recreational pavements and other impenetrable surfaces combined which led to the continuing expansion of constructed areas of the city.

During this time, the change in urban landuse can be related to population growth and industrial development. Biodiversity loss and decreasing environmental conditions are the result of rapid urbanization. Urban settlements are dangerous for the natural habitat because road networks, recreational infrastructure, buildings, schools and colleges, have provided open ended places which has forced natural habitat to settle themselves at safer places.

Results show that the forests, mainly found in 2000, on the western margins, were fully converted into sparse vegetation by 2020 due to several reasons, such as stone quarries, agricultural practices to cater the food demands of increasing population, timber cutting for the consumption of fuel by the villagers, and factual cement industry which borders the western periphery and therefore created vacant areas. Figure 8 (C) represents that built-up expansion shifted towards south eastern and western side of Islamabad city.

Figure 8 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 8. Analysis of built-up area

Topographical analysis

Figure 9 (A) DEM represents the 3D shape of terrain and also used as input to extract stream network. (B) Flow direction was computed from DEM (C) the flow was accumulated and the streams are defined (D) Major drainage network was extracted from the flow accumulation (E) Catchment area of watershed was delineated through point of origin. (F) watershed and drainage stream network, reflects the structural arrangement of rocks, where stream bends represent the existence of hard/soft rocks beneath the earth’s surface that drive water in a complex way like neural network in human body. (G) Slop was extracted from DEM for evaluating the factors behind the urban expansion. (H) soil data is very important factor for land-use and land cover variation. (I) earthquake zones are also important for the evaluating the risk assessment as the Islamabad lays on the fault lines therefore it is not considered comparatively safe.

The geological map of study site is in Figure 9(F) which show that Islamabad is located on the fault lines which are dangerous and the earthquake may hit this area any time which leads to huge disaster in coming future therefore this region is unsuitable for megastructures even for setting up small localities.

The Figure 9 (D) is showing that most of water channels were found in SE direction and if we compare it with Figure 8 (c), it shows that the trend of population was also in the same direction. This resemblance signifies that people rush toward water channels to manage their daily routine in a better way.

Figure 9 (G) is showing that there were gentle slopes in southern parts of study site while steep slopes were observed in extreme north. Steep slopes are considered unsuitable for living therefore about 99% of urban settlements were found toward gentle slopes.

Figure 9(H) is showing that the NE of study site is dangerous for human settlements because this area was found prone to earthquakes. Luckily most of urban settlements were not found on this site and it is recommended the land authority must not approve any new settlement/mega project on this area.

Conclusion.

This study is unique in context of examining the LULCC by incorporation local topography including fault lines, drainage network and hazardous areas. It is observed that urban growth is very fast and eating up not only barren lands but also very fertile agricultural lands. A specie is restricting with certain ecological conditions which may not be grown at odd places and if an artificial ecological condition is created at odd places, the outcomes may not be economically sound. Therefore, it is recommended that government must take strict action on emergency footings to demarcate urban lands so that the agricultural lands must remain intact to save flora and fauna of the city and to get sustainable agricultural developments.

Figure 9 Assessment of Temporal Changes in Landuse Patterns by Incorporating Topographical Parameters

Figure 9. (A) DEM (B) Flow direction (C) Flow accumulation (D) Major drainage network (E) Draining network (F) Geological map (G) Slop map (H) Hazard map

Acknowledgement. The author would like to acknowledge Dr. Ali IqtadarMirza for his guidance and supervision.

Author’s Contribution. All authors have contributed equally.

Conflict of interest. The authors declare no conflict of interest in publishing this manuscript in IJASD.

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