Spatial Process of Urbanization in Kathmandu Valley, Nepal

Abstract

Urbanization is a complex spatial process that converts rural land uses to urban uses, and causes various impacts on ecosystem structures, functions, dynamics, and the livelihoods of human beings. Kathmandu Valley, the most populous metropolitan region in Nepal, has been rapidly urbanizing since the 1980s. Due to the urbanization pressure, the valley has been facing serious environmental consequences in recent years. Therefore, the quantification of the spatial process of urbanization is essential for the monitoring and assessment of the changing environment of the valley. This research aims to investigate the spatial pattern of urbanization since the 1960s and identify the driving factors of urbanization. Remote sensing, geographic information systems, spatial metrics, analytic hierarchy process, and fieldwork techniques were applied in order to prepare time series land use maps, interpret spatial pattern changes, and analyze the urbanization process. A highly dynamic spatial pattern of urbanization is observed in the valley. The urban built-up areas, which are used as an indicator of urbanization, had a slow trend of growth in the 1960s and 1970s but have grown rapidly since the 1980s. Prime agricultural land in the valley floor has been changed to urban/built-up areas. Shrubs and forest landscapes in rural areas mostly changed into agricultural uses, while half of the land in the valley has remained agricultural. Nominal land use transitions between the other land use types in the valley were also noticed. The urbanization process of individual uncontrolled housing practices has developed fragmented and heterogeneous land use combinations in the valley, but urban growth has gradually become more synchronized in recent decades. ii However, a refill type of development process in the city core and immediate fringe areas has shown a decreasing trend of the neighborhood distances between the different land uses, and an increasing trend of physical connectedness, which indicates a higher probability of homogenous landscape development in the upcoming decades. The dynamic pattern of urbanization, particularly for the last decade, has been greatly influenced by seven driving factors: physical conditions, public service accessibility, economic opportunities, land market, population growth, political situation, and plans and policies. These factors have played important but different roles in the core, fringe, and rural areas. Among these factors, economic opportunities in the core, population growth in the fringe, and the political situation in the rural areas are identified as the highest impact factors of urbanization. The physical conditions factor has had the least effect in the core and fringe areas as compared to its role in the rural areas. The role of public service accessibility gradually decreased from city core to rural area. Due to the lower land availability in the city core, the land market factor had less of a role in the core compared to the fringe and rural areas. The plans and policies factor is evaluated as less effective in all thematic areas. This empirical analysis revealed the spatial process of urbanization in the valley, which is an important reference for the urban and regional planners in Nepal and other less developed countries. Furthermore, the research results form an important data source for predicting urban growth dynamics and scenario analysis. Keywords: Land Use Change, Analytic Hierarchy Process, Spatial Metrics, Driving Factor Modeling, Hybrid Method, Urban Remote Sensing, LULC, GIScience.