Studies on Land Use/Land Cover Changes and Water Quality Due to Urbanization Along the Coastal Areas of Dakshina Kannada District, Karnataka, India

Abstract

Increasing population and urbanization result in land use and land cover changes from local to global scales. The coastal area of Dakshina Kannada district of Karnataka, India has witnessed a phenomenal development in the last couple of decades and it is expected that this trend will continue at a much faster rate due to the setting up of Special Economic Zones (SEZs) and their expansions in Mangalore. Therefore an attempt was made in this research to study the land use/land cover changes that have taken place for 25 years from 1983-2008 and to assess the urbanization impacts on water quality. The study area lies between 12°45’ N to 13°7’30” N latitude and 74°45’ E to 75° E longitude having an area of about 777 square kilometres. Six Indian Remote Sensing (IRS) satellite images were used in the study. Supervised classification with maximum likelihood algorithm was adopted in the study and the accuracy assessment was done. The results indicate that the urban/built-up area has increased by 270% and the population has increased by 215% during the study period. A total of 1500 water samples pertaining to sea, rivers and groundwater were collected during November 2006 and October 2007 and analyzed for twenty five physical, chemical and bacteriological characteristics. The over all quality of groundwater in Mangalore city was seem to be deteriorating. The pH value showed a decreasing trend, while the concentration of Nitrates showed increasing trend, though at present it is well within the standards. The global water quality indices determined for River Nethravati varied from ‘Fair’ to ‘Good’ and the indices for River Gurpur can be categorized as ‘Fair’. Urban growth prediction helps the urban planners and policy makers in providing better infrastructure services to a huge number of new urban residents. In the study area, the urban/built-up area is predicted to increase to 381 sq. km and the population is expected to reach 2.6 millions by the year 2028. The population in the study area has already reached saturation levels; therefore any further increase in population will result in environmental degradation. This indicates that the available resources are not sustainable and the carrying capacity of the region is untenable.