ENVIS Technical Report: 114,  July 2016

Bangalore (Figure 2.1) is located in the Deccan plateau, toward the south east of Karnataka state extending from 12o49’5”N to 13o8’32”N in latitude and 77o27’29” E to 77o47’2”E in longitude. Bangalore city is/was known with various names such as “GANDU BHOOMI” (land of heroes), “BENDAKAALURU” (land of boiled beans), “LAND OF LAKES” where a large number of lakes were constructed to store water, during the regime of Kings and British, along with it, numerous parks, gardens were created such as Lalbagh, Cubbon park etc. which gained the city with name “GARDEN CITY”. Post-independence due to industrialization, growth in technology and science, the city acquired “Silicon Valley” status and provided job opportunities. However, during post independent era, with globalization the city lost its glory due to unplanned, unrealistic and irresponsible urbanisation.

Figure 2.1: Bangalore (Bengaluru) City

Growth of Bangalore from  Pete’s to Bruhat Bengaluru: Bangalore, the pride to India as the garden and cool city, is about 500 years old has grown from a small time settlement when Kempe-Gowda, the architect of Bengaluru, built a mud fort in 1537 and his son marked the city boundaries by erecting four watch towers. Within the fort the town was divided into pete’s (commercial localities) such as Chickpete, Dodpete, Balepete, Cottonpete and other areas earmarked for different trades and artisans. The town had two main streets, Chickpete Street ran east to west and Dodpete Street ran north to south, their intersection forming Dodpete Square, the heart of Bangalore. Chikkadeva Raya Wodeyar (1673 AD- 1704 AD) built an oval shaped fort south of the old mud fort. Later, Hyder Ali took over the throne until the British defeated him in 1790. During this period, the oval fort in the south was rebuilt with stone and palace was built within the fort, the town was about 5 kilometer’s in circumference, with the fort at the south end, with well-planned streets and prosperous shops indicating a flourishing economy. A big market stretched from the north gate of the town to the oval fort, a predecessor of today’s Avenue Road. Hyder Ali and Tippu Sultan also contributed towards the beautification of the city by building Lalbag Garden in 1760 AD, developed Bangalore into a commercial and military centre of strategic importance. The British after defeating Hyder Ali and Tippu Sultan, ceased Bangalore as strategic stronghold   and built military base and cantonment in the city. Sooner Bangalore fort slowly passed into extinction, while the fort walls coming down in stages to make way for the expanding city. The Parade Ground, surrounded by a ride or mall called Rotten Row, was more or less the heart of Bangalore Cantonment. Around this, the Civil & Military Station (CMS) was developed. A civilian population of lower economic strata, attracted by the opportunities for employment and trade and offering subsidiary services to the military personnel, settled in a high density and congested locality. This area evolved into a general bazaar called Blackpally, today’s Shivajinagar. During the British rule, several developments, led to the rapid growth of the city. The most important of these being the telegraph connections introduced to and from Bangalore to all the important cities of India in 1853 AD and the rail connection to Madras in 1864 AD. Hence, with city walls receding, giving way to an unprecedented growth with sprawl at ouskirts. By 1881 AD, Bangalore had two nuclei: one a high-density area around the fort and its market (K.R. Market area) in pete and the second Blackpally (Russel Market area) within the colonial city. Both of these comprised the inner city of Bangalore with Cubbon Park acting as a large green buffer. Several suburbs were built, by 1931 AD the CMS’s population was 134,113 and that of Bangalore was 308,000. Post-Independence the colonial cities were merged in 1949 since then Bangalore was retained the capital of Karnataka state. Bangalore continued to grow and several public sector industries were setup between 1940 and 1970 transforming the city to science and technology centre. By 1961, Bangalore had become the 6th largest city in India with a population of 1,207,000. Between 1971 and 1981, Bangalore’s growth rate was 76%, the fastest in Asia. By 1988 the Electronic City had been developed and Bangalore emerged as India’s software capital. Consequently the 1990’s saw a construction boom fuelled by Bangalore’s growing reputation as “India’s silicon valley”. Since the construction boom, many legal and illegal activities/developments has led to increase in land conversion from one form to constructed and paved surfaces violating the norms (CDP’s). Table 2.1 lists chronologically the increase in city’s spatial extent since 1700 (http://www.karnataka.com; https://archive.org/details/BangaloreGazetteer1875).

Table 2.1: Spatial increase of Bangalore city

The decadal (during 2001 to 2011) increase in population for urban areas of India is 31.8% and in Karnataka is 31.5%, but Bangalore has a decadal increase of 44%, higher compared to that of the state and country. The decadal population (w.r.t BBMP limits) has increased from 5.8 Million (in 2001) to 8.4 Million (in 2011); the population density has increased from 7880 persons per square kilometer to over 11330 persons per square kilometer. Characterized by undulating topography with green cover and water bodies, the temperature varies from 22oC to 38oC during summer and 14oC to 27oC in winter. Bangalore receives an annual average rainfall of 800 mm. The undulating terrain (varying from about 700 m to about 962 m AMSL) in the region aided in the formation of interconnected lakes in the region.

Geologically, the prevailing rocks are light to dark grey Biotite Granitic Gneiss and varies from place to place in texture, structure and appearance based on the fineness or coarseness of the grains, mode of disposition of dark minerals. The dark minerals are mostly biotite mica are generally arranged in parallel orientation, the light coloured are silicious minerals. The gneissic rocks have portions of uniform granitic texture; these gneissic masses have been styled as ‘Peninsular Gneiss’. Schist’s are not prominent, but isolated stringers of dark hornblend granulite are with light green pyroxene rocks. Other rocks include the dykes and dolerites. Kaolin is a good variety of clay, found in the silts of the lake (http://www.geosocindia.org).
Bangalore City was once aptly known as ‘city of lakes’ due to the presence of large number of lake (about 285 lakes). These lakes were all interconnected with canals / drains (kaluveys’s) to enable transferring excess water to the next lake. These lakes catered the basic needs such as maintaining and recharging ground water, drinking water to the surrounding people, habitat for fishes and other aquatic ecosystems, sustaining food (fish, etc.) and agricultural activities, etc.

The drainage network in Bangalore carries water to the River Cauvery through its tributaries Arkavathi, Pinakini or Pennar and Shimsha. The central, northern and eastern portion is undulating with the upland tracts occupied by scrubs, while the low lands occupied by series of tanks formed by embanking the streams along the valley. These valleys consists of varying size water bodies from small ponds to large lakes. The southern portion of the land consists of hills that are close together and are surrounded by thick jungles.

Figure 2.2: River and Lake network along the Major valleys

Bangalore being located on the ridge, forms three watersheds as precipitation flows as runoff in three directions along  the valleys (Figure 2.2) - Koramangala Challaghatta Valley (K&C Valley), Hebbal Valley (H Valley) and the Vrishabhavati Valley (V Valley). Under the administrative boundary of Bruhat Bengaluru, K&C valley is the largest encompassing an area of 255 square kilometers, followed by Hebbal valley with an area of 207 square kilometers and Vrishabhavati valley with an area of 165 square kilometers. Both K&C valley and Hebbal valley joins at Nagondanahalli village (BBMP Ward 94 – Hagadur) which further flow to Dakshina Pinakini River, where as Vrishabhavati valley joins Arkavathi river which is a tributary of river Cauvery.
The number of lakes in Bangalore has reduced from nearly 285 (spatial extent of Bangalore: 161 sq.km. in early seventies) to 194 (spatial extent of Bangalore: 741 sq.km. in 2006). Unplanned rapid urbanisation during late nineties, witnessed large-scale unrealistic, uncontrolled developmental activities in the neighborhood of lakes, which  led to

1. encroachment of lakes and storm water drains resulting in decline in ground water table, while increasing the instances of flooding;
2. decline in native species of biota in the lake ecosystem;
3. dumping of solid waste (MSW), Construction debris, etc. in storm water drains, lake catchment and in lakes.;
4. sustained inflow of partially or untreated sewage, polluting existing surface and subsurface water resources;
5. reduced water holding capacity due to accumulation of silt; construction debris, etc.;
6. topography alterations in the lake catchment;
7. sustained inflow of untreated industrial effluents; and
8. pollution due to enhanced vehicular traffic.

Anthropogenic activities particularly, indiscriminate disposal of industrial effluents and sewage wastes, dumping of building debris have altered the physical, chemical as well as biological integrity of the ecosystem. This has resulted in the ecological degradation, which is evident from the current ecosystem valuation of wetlands. Valuation of goods and services from a relatively pristine wetland in Bangalore shows the value of Rs. 10,435/ha/day (much higher than global coastal wetland ecosystems  with a total annual of US$ 14,785/ha), while the polluted wetland shows the value of Rs.20/ha/day (Ramachandra et al., 2005) and sewage fed Varthur wetland has a value of Rs.119/ha/day (Ramachandra et al., 2011). The pollutants and subsequent contamination of the wetland has telling effects such as disappearance of native species, dominance of invasive exotic species (such as African catfish, water hyacinth, etc.), in addition to profuse breeding of disease vectors and pathogens.