Dr. Bhagawat Rimal
Everest Geo-science and Information Service Center, Kathmandu, Nepal
Land-use and land-cover (LULC) change, as one of the main driving forces of global environmental change, is central to the sustainable development debate. It affects a wide range of environmental and landscape attributes including the quality of water, land and air resources, ecosystem processes and function, and the climate system (Lambin, Rounsevell, Geist, 2000).
On the other hand, history of urban growth indicates that urban areas are one of most dynamic places on the earth‘s surface. Despite its regional economic importance, urban growth has a considerable impact on the surrounding ecosystem (Yuan et al. 2005). Urbanisation is one of the most important anthropogenic activities that create extensive environmental implications at both local and global scales. Dynamic urban expansion models are useful tools to understand the urbanisation process. They project spatiotemporal dynamics and provide useful information for assessing environmental implications of urbanisation (Wu et al. 2009). Urbanisation has become a major trend worldwide in recent years. In 1920, urban population made up 14 percent of the world and reached 25 percent in 1950 (Weber 2003, Thapa and Muriyama, 2009). By the middle of 2009, number of people living in urban areas, more than 3.42 billion, had surpassed the number of people, living in rural areas (3.41 billion) and since then the world has become more urban than rural. According to the Census 2011 by the Central Bureau of Statistics, Nepal, the urban population of Nepal increased from 2.9 percent in 1952/1954 to 17 percent in 2011.
Land use change is influenced directly by infrastructural development, where all types of human facilities are concentrated. Migration, globalisation, government plan and policies, and political condition are the other factor of urban development and land use change of city (Rimal, 2011). The major objective of this study is to analyse the actual spatiotemporal dynamics and evolution of land use change and urban development of Kathmandu city, Nepal.
Causes of land use change can be divided into two categories: proximate (direct or local) and underlying (indirect or root). The proximate causes of land-use change explain how and why local land cover and ecosystem processes are modified directly by humans, while underlying causes explain the broader context and fundamental forces underpinning these local actions ((Ellis, 2007).
This study is based-on remote sensing (RS) and GIS technology. These technologies are efficient tools for earth observation and information analysis. They provide capacity in scientific investigations, resource management, environmental impact assessment, development planning, cartography and road network planning. These technologies also have high capacity in surveying and monitoring LULC and land cover dynamics in diverse environments, for example, mountainous landscape, coastal zone and along rivers (Baban, Kamaruzaman, 2001; Fromard et al., 2004, Muttitanon and Tripathi, 2005).
2. Method and materials
2.1. Study area
The study area comprises two heavily populated urban centres, Kathmandu metropolitan city and Lalitpur sub-metropolitan City. Study area Kathmandu metropolitan city and Lalitpur sub- metropolitan city lie in the location between, 27° 27’ 47’’ north latitude to 27° 45’ 00’’ north latitude and 85° 16’ 45’’ eastern longitude to 85° 22’20’’ eastern longitude of Nepal with over an area of 64.58 square kilometres. The city can be separated into five sectors – the central sector, east sector, north sector, city core and west sector. The altitude of the city varies from a minimum of 1266 metre to a maximum of 1400 metre above sea level that shows the relative flatness of the ground on which the city is located. Most of the precipitation occurs between June and August as a result of southeast monsoon winds. Some rainfall occurs during the winter, brought by trade winds from the northwest (HMGN, 1969, Thapa, 2009). The slopes are very low (less than 1 degree), and the soils have a predominantly loamy and boulder texture (Haack and Khatiwada, 2007). The city is drained by Bagmati and Bisnumati River. The river system is the main sources of drinking water and irrigation of city area.
Figure 1: Location Map of Study area
2.2. Data sets
This study includes both field survey and map studies and computer-based analysis. In primary session, fieldwork was conducted to acquire first hand data required for the research. Most of the essential data for improving mapping accuracies of spatial changes were collected through the fieldwork. Landscape observations, meetings with experts, and structured interviews were conducted in the sub- metropolitan area. For this study, land use/land cover maps and topographical maps of the study area were necessary. Possible latest topographic maps of the region were acquired. The maps collection from 1978, 1992 and 2001 were selected for change analysis based upon their perceived accuracy and their similarity in general mapping parameters. First, 1976 data are obtained from land use maps the scale of 1:50,000 compiled from ground-verified aerial photographs (1:50,000) by the Land Resources Mapping Project (LRMP), a collaboration between His Majesty‘s Government of Nepal (HMGN) and an external consultant (Kenting Earth Sciences Ltd, Ontario, Canada). Topographical map the scale of 1: 25,000 has been used for the analysis of images was published by Survey Department, Government of Nepal on the dated 1996. The map is based on the aerial photograph at the scale of 1:50000 taken in 1992.
Four pairs of cloud-free Landsat images, acquired from the University of Maryland, Global Land Cover Facility, US website , Michigan University, USGS Global Visualization Viewer: ttp://www.glovis.usgs.gov have been used to classify the study area images: Landsat Image 2,Multi Spectral Scanner satellite image (hereafter MSS image with path /row 152/41) October 28, 1976, ,Landsat Image 5, Thematic Mapper satellite image (hereafter TM image with path/ row 141/41 ) October 31, 1989 and Landsat 7 Enhanced Thematic Mapper (hereafter ETM+ with path/ row 141/041 ) December 27, 2001 and Landsat 7 Enhanced Thematic Mapper (ETM+ with path/ row 141/41 ) January 15, 2009. All data used in this study were rectified in the Universal Transverse Mercator projection system that is UTM World Geodetic System 1984.
The IDRISI GIS Taiga version has been used for the analysis of image. According to the land use classification scheme unsupervised and supervised approach with the maximum likelihood parameter (MLP) system was applied to improve the accuracy of the land use classification for the images for all four dates (1976, 1989, 2001and 2009). The classification system utilised in this study is a slightly modified classification system for remotely sensed data as recommended by Anderson et al. 1976 and the system utilised by the Land Information Centre in study area. For simplicity, five types of land use classes: urban/built-up, water body, forest, open field and cultivated land, were selected for the study. Classification accuracy assessment is a general term for comparing the classification of geographical data that are assumed to be true to determine the accuracy of the classification process. A total 60 stratified random sampling point were created for the accuracy of classification. The supervised classification accuracies of 85 percent, 98 percent, 98 percent and 97 percent were achieved for the years, 1976, 1989, 2001 and 2009 respectively.
3. Result and discussion
3.1 Population growth and distribution in Kathmandu
The national census of 2001 counted 671,846 persons and 152,155 households in the Kathmandu metropolitan. There are altogether 35 wards in Kathmandu metropolitan city whereas the maximum population has settled in ward no 16. It is 45450 with 10789 house hold. And the minimum population has settled in ward no.26 which is 3764 with 757 household.
According to the population census 2001, total population of Lalitpur sub-metropolitan city is 162,991 and is constituted by 84,502 males and 78,489 females living in a total of 34996 households with an average family size of 4.66 persons. There are 22 wards the maximum number of population in ward no.14, total 11530 with 2498 house hold and minimum in ward no.11 with 4238 in population with 780 house hold . Figure 2, 3 and 4 mentioned the ward wise population distribution of Kathmandu and Lalitpur.
Figure 2: Ward wise population and household in Kathmandu metropolitan -2001,
Figure.3: Ward wise population and household in Lalitpur sub-metropolitan -2001,
Figure 4: Ward wise population distribution of Kathmandu City -2001
The pattern of the growth in total urban population and annual population growth rate of Kathmandu in censuses since 1952/54 is presented in table 1 and figure 5. According to table, the annual population growth rate is increasing per year; it is 1.27 in 1961 and 4.51 in 2001. In the last five decades or so, Kathmandu’s population has increased from 148762 to 834837 that is an increase by a factor of 5.6 times. According to study (Thapa, Murayama, Ale, 2008) projected population has 1240957 and annual growth rate is 4.04 in 2011 AD in the city area.
Table 1: Growth rate of urban population in Kathmandu, 1952/54-2011,
Sources: Sharma (2003) and Pradhan and Perera (2005).Thapa, Murayama, (2008), Rimal (2011), CBS (2011).
Note: In all tables, Kathmandu is defined as Kathmandu Metropolitan City and Lalitpur Sub-Metropolitan City taken together. P (Projected population), APGR (Annual population growth rate).
Figure 5: Growth of urban population in Kathmandu, 1952/54-2011
Note: In all figures, Kathmandu is defined as Kathmandu Metropolitan City and Lalitpur Sub-Metropolitan City taken Together
3.2 Quantify the magnitude of land use/cover change 1976-2009
How and where the land has been changed? In which period intensification and expansion of land use have occurred? And what are the consequences of land cover change? Study attempted to answer all the questions above and know land use/land cover transition in Kathmandu in between 1976-2009.
Table 2 provides the land use statistic of Kathmandu and table 3 mentioned the quantify information regarding the areal extend of each land cover types and magnitude of land cover change within three land cover maps: 1976-1989, 1989 to 2001 and 2001 to 2009. The urban area 8.95 km² has been added from 1976 to 1989, and from 1989 to 2001 and 2001 to 2009, the urban area with 12.29 km² and 14.45 km² have been added respectively. It has been expanded from 8.97 km² to 44.66 km² in between 1976 to 2009. During this period, 35.69 km² (55.26 %) area has been added in urban area. On the other hand, forest area, open field and cultivated land have been decreased from the beginning. Remaining water cover area had a mix of increase and decrease. Population migration from various places, infrastructure development and other various driving forces are responsible to decrease the cultivated land. Water covered area seems 3.00 km², 2.00 km², 3.43 km² and 3.24 km² in 1976,1989, 2001, and 2009 respectively which signifies the fluctuating ratio of water covered area.
In the period of 1976 to 2009, water covered area increased by 0.24 km² (0.37 percent). Similarly, forested covered area has been decreased with major ratio and this area changed into cultivated and water body. Mean while, 2.06 km² (3.19%) open field has been decreased in between 1976 to 2009. From the beginning cultivated area has been decreasing. This area dramatically declined and reached to 15.17 km² in 2009 which had covered 42.77 km² in 1976 and it declined by 5.22 km² area in between 1976 to 1989 and in between 1989 and 2001 it decreased by 8.50 km² and 13.88 km² in between 2001 and 2009. During the period of 1976 to 2009, altogether 27.60 km² (42.73 percent) agricultural area has been transformed into other land use area. Figures 7, 8, 9, and 10 represented the land use change pattern of study area.
Table 2: Land use statistic of Kathmandu, 1976– 2009
Table 3: Quantify magnitude of and use/and cover change 1976-2009
Figure 6: Trend of land use change in Kathmandu
Figure 7: Land use map of Kathmandu 1976
Figure 8: Land use map of Kathmandu 1989
Figure 9: Land use map of Kathmandu 2001
Figure 10: Land use map of Kathmandu 2009
3.2.1 Land use/cover change 1976 to 1989
Mentioned transition table 4 of 1976 to 1989 shows that, 6.74 km² urban area has remained in urban in which altered 0.13 km² in water, 0.17 km² in forest and 1.93 km² in cultivated land respectively. Mean while, 0.42 km² of water body converted into urban area, 0.04 in forest and 1.18 in cultivated land. Similarly, forest cover area also helped to increase the urban area and cultivated land. In this period (1976-1989), 1.79 km² forest area has been transformed in urban and 2.60 km² in cultivated land. Likewise, 0.66 km² open field has been altered in urban land and 1.28 in cultivated land. Meanwhile, 8.32 km² cultivated land has been decreased and transformed in urban area, 0.48 km² cultivated area had transformed into water, 2.75 km² in forest and 0.67 km² in open field in the period of 13 years.
Table 4: Land use transition in km² (1976 -1989)
3.2.2 Land use/cover change in 1989 to 2001
The table 5 shows the change in land use and land cover in the period of 1989-2001. A different phenomenon of land conversion is observed in this period in comparison to the earlier time period. The transformation of agricultural land into urban/built-up areas was escalated 12.94 km² but the transformation of the other land uses into urban area remarkably decreased. However, 1.49 km² urban area has been transformed into cultivated land. Likewise, 0.09 km² water bodies have been changed into urban and 0.29 km² in cultivated land. Forest with the area 0.90 km² has been transformed into urban, 0.81 into water, 3.16 km² in cultivated respectively. Similarly, 0.74 km² open field has altered in cultivated land. Other land use classes have changed in minor ratio.
Table 5: Land use transition in km² (1989-2001)
3.2.3 Land use/cover change in 2001-2009
During this period (2001-2009), two major land use transitions were observed. According to table 6, a significant amount of cultivated land that is 14.74-km² area has changed into urban/ built up lands. By this change, we can observe that, urban area has been increasing day by day and agricultural area is going to finish. In this period, 1.15 km² urban area has been transformed into agriculture. Likewise 1.20 km² water body has been altered into urban area and 0.20 km² in cultivated land. Similarly, 0.05-km² forest area has been converted into urban, 0.22 into water and 0.29 km² into cultivated land. In the same way, 0.09 km² open field area has altered in urban and 0.17 km² in cultivated land.
Table 6: Land use transition in km² (2001-2009)
Urbanisation is relatively a new phenomenon in Nepal. Attraction of people towards the urban area is high and the ratio of land use and land cover change is increasing every day. Increasing population caused the spatial pattern of urbanisation to be highly dynamic in Kathmandu city. The city is capital of the country with a high concentration of administrative facilities and subsidiaries of multinational corporations. This unique political and geographic situation has greatly facilitated the outward expansion of urban land use in a speed and scale more significant. Landsat image of 1976 clearly showed rich cultivated land and water resources in Kathmandu but this land use classes rapidly has transformed into urban area. The urban/built-up areas in the Kathmandu had a noticeable enlarge, from the analysis we can see that the urban development amend is very high in the city area.
The core city area is going to be the dense jungle of concrete in no year. Due to the unplanned settlement and the unmanaged urbanisation, the life in the city area is appearing down. Because of the overflow of the mass in the city and the nearby areas, huge cultivated lands, water body, open fields and forest areas have been turning into settlement areas. It creates environmental degradation which also refers to the imbalance in the ratio of the land use and land cover categories. The fraction of urban rises very high in comparison to the other land use classes namely forest, water cover area, open area, cultivated land and the sandy area. Several other fast growing and emerging municipal towns are also facing similar environmental problems. In the name of utilizing the natural resources, people are blindly destroying them.
It is the high time that the concerned authorities should be conscious. The government should immediately pass out some effective and sustainable rules and bring them in action. The land plotting system and its market should either be discouraged or should be hold by the government itself. Through the decentralisation process, the urban facilities should be scattered in every remote villages. Due to the rapid development in the village areas, the flow of the migrants towards the city areas can be lowered down. Imitating the urbanisation of the developed countries has nothing to do with the underdeveloped third world countries like Nepal. Specific and appropriate urban plans and policies suitable to the country should be brought into action. For the better and fruitful urbanisation, the unproductive barren lands should be chosen for the residential purpose whereas the fertile land should be used for the cultivation. The decentralised plans and policies, rural area development package programmes, well managed urban settlement etc can be some helpful concepts to assist in controlling the urbanisation.
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