Spatio-temporal landscape modeling of urban growth patterns in Dhanbad Urban Agglomeration, India using geoinformatics techniques

The study deals with the quantification of urban sprawl and land transformation of Dhanbad Urban Agglomeration (DUA) using geoinformatics and gradient modeling during last four decades (1972-2011). Various multi-temporal satellite images viz., MSS (1972), ETM+ (1999, 2011) and digital elevation model (CARTOSAT I, 2006) were used to analyse the urban expansion, land transformation, growth directions, and spatial segregations within the urban landscape to develop an understanding the nature of built-up growth in DUA. The urban area increased from 10.33 km2 to 46.70 km2 (352.08%) along with high rate of population growth (160.07%) during 1972-2011 exhibiting population densification in DUA. The study reveals that coal mining based city faced significant land use transformation converting vegetation (−41.33%) into built-up land (352.08%) exhibiting loss of productive lands for the expansion of impervious surface. The per year urban growth exhibited increasing urban growth from 0.4 km2/year to 1.51 km2/year during 1972-1999 and 1999-2011 periods with overall growth of 332.73%. The built-up growth on varied elevation zones exhibits that the elevation zones 150-200 m is the most preferred (79.01%) for urban development with high growth (541.74%). The gradient modeling represents that the percentage of land (built-up) gradually increased from 3.48% to 15.74% during 1972-2011. The result exhibited that the major growth took place in south-west direction followed by south direction in haphazard manner during 1971-99 period, whereas predominant built-up development was observed in north, south and south-west direction during 1999-2011 period, majorly within the municipal limits. The study provides an analytical method to evaluate the built-up growth patterns of an urban milieu combining geoinformatics and landscape matrix. The built-up growth in DUA indicates urgent imposition of building bylaws along with zoning (land use, height and density) regulations to transform DUA as liveable city.