Greater Bangalore (77°37’19.54’’ E and 12°59’09.76’’ N) is the principal administrative, cultural, commercial, industrial, and knowledge capital of the state of Karnataka with an area of 741 sq. km. Bangalore city administrative jurisdiction was widened in 2006 by merging the existing area of Bangalore city spatial limits with 8 neighbouring Urban Local Bodies (ULBs) and 111 Villages of Bangalore Urban District (Ramachandra and Uttam Kumar, 2008; Sudhira et al., 2007). Thus, Bangalore has grown spatially more than ten times since 1949 (69 square kilometers) and is a part of both the Bangalore urban and rural districts (figure 1). Now, Bangalore is the fifth largest metropolis in India currently with a population of about 7 million (figure 2). The mean annual total rainfall is about 880 mm with about 60 rainy days a year over the last ten years. The summer temperature ranges from 18° C – 38° C, while the winter temperature ranges from 12° C – 25° C. Thus, Bangalore enjoys a salubrious climate all round the year. Bangalore is located at an altitude of 920 metres above mean sea level, delineating four watersheds, viz. Hebbal, Koramangala, Challaghatta and Vrishabhavathi watersheds. The undulating terrain in the region has facilitated creation of a large number of tanks providing for the traditional uses of irrigation, drinking, fishing and washing. This led to Bangalore having hundreds of such water bodies through the centuries. Even in early second half of 20th century, in 1961, the number of lakes and tanks in the city stood at 262 (and spatial extent of Bangalore was 112 sq km). However, number of lakes and tanks in 1985 was 81 (and spatial extent of Bangalore was 161 sq km).
Figure 1: Study area – Greater Bangalore.
Figure 2: Population growth and population density.