1.6 Study area:
Bangalore, the fifth largest and fastest growing city in India, has a decadal population growth of 39% (with 87,49,944 populations as per 2011 census). The Begur Nageshwara Temple was commissioned around 860, during the reign of the Western Ganga King Ereganga Nitimarga was the oldest existing monument. Bangalore’s reputation as the Garden City of India began in 1927 with the Silver Jubilee celebrations of the rule of Krishnaraja Wodeyar IV. Several projects such as the construction of parks, public buildings and hospitals were instituted to improve the city. Even today, the city administration manages to maintain several parks. Cubbon Park and Lal Bagh are two such examples. Bangalore’s tree-lined avenues, parks, and abundant greenery have made it ‘Garden City’ of India. It has acquired the name of ‘Silicon City”, due to its progressive trend in Information technology. the beginning of the 20th century brought prospectus for the towns and industries with the Mysore government setting up the hydroelectric project at shivana samudram in 1902-03 and Bengaluru is the first city to be electrified in 1905. The Indian Institute of Science was established in 1909, which subsequently played a major role in developing the city as a science research hub. Bangalore is a divisional headquarters in the South Western Railway zone of the Indian Railways. There are four major railway stations in the city: Krantiveer Sangolli Rayanna Railway Station, Bangalore Cantonment railway station, Yeshwantapur junction and Krishnarajapuram railway station,
Bangalore University, established in 1886, provides affiliation to over 500 colleges, with a total student enrolment exceeding 300,000. The university has two campuses within Bangalore – Jnanabharathi and Central College.206 University Visvesvaraya College of Engineering was established in the year 1917, by Bharat Ratna Sir M. Visvesvaraya, At present, the UVCE is the only engineering college under the Bangalore University. Bangalore also has many private Engineering Colleges affiliated with Visvesvaraya Technological University. In June 1972 the Indian Space Research Organisation (ISRO) was established under the
Department of Space and headquartered in the city. Bangalore is served by Kempegowda International Airport (IATA: BLR, ICAO: VOBL), located at Devanahalli, about 40 kilometres (25 miles) from the city centre. It was formerly called Bengaluru International Airport. The airport started operations from 24 May 2008 and is a private airport managed by a consortium led by the GVK Group.
RAINFALL AND CLIMATE
The average annual rainfall is about 931 mm with 60 rainy days (Source: Indian Meteorological Department). It lies in the rain shadow region. The only source of water for this area is rainfall; Highest rainfall occurs during the south-western monsoon during September. The rainfall of the district is accounted by the Pre monsoon (PRE), SW monsoon (SWM) and NE monsoon (NEM). Majority of the rainfall is contributed by SW Monsoon. In general, humid to semi arid climatic conditions prevail in the district. The average temperature is around 23.1?C. The seasonal and annual normal rainfall of the four taluks of the district from the year 2001 to 2010 is considered for studying the rainfall pattern. The annual rainfall of Bangalore North taluk is the highest with 1157mm and lowest for Anekal taluk with 890mm. Bengalore falls into the area of semi-arid tropics. Bengalore enjoys a salubrious climate all around the year as the summer temperature ranges from 18° C to 38° C while the winter temperature ranges from 12° C to 25° C (Santosh Kr. Singh., 2009; Sudhira et al., 2007). Bangalore has a tropical savanna climate (Köppen climate classification Aw) with distinct wet and dry seasons. Due to its high elevation, Bangalore usually enjoys a more moderate climate throughout the year, although occasional heat waves can make summer somewhat uncomfortable.71 The coolest month is January with an average low temperature of 15.1 °C (59.2 °F) and the hottest month is April with an average high temperature of 35 °C (95 °F). The summer heat is moderated by fairly frequent thunderstorms, which occasionally cause power outages and local flooding. Most of the rainfall occurs during late afternoon/evening or night and rain before noon is infrequent.
Figure 1.2: Study area Bruhat Bengalore Mahanagara Palike
Figure 1.3: Drainage pattern of Bengaluru
Physiography: the area forms undulating terrain the central ridge running in the middle. the significant portion of the area slopes towards south and south-west with series of NNE and SSW trending hills. the drainage pattern is trillies to subdendretic. No major rivers run through the city. Towards the west of the central ridge, River Vrishabhavathi arises within the town at Basavanagudi and flows through the town. River Arkavathi originates at Nandhi hill, 60 kilometres (37 miles) to the north, and a few portion of Basin falls within city limits. The rivers Arkavathi and Vrishabhavathi are subsidiaries of Kaveri river. Towards the east, the Hebbal Vally and Koramangala Challagatta valley exist, which is part of pinakini river , and they later form Ponnaiyar (South Pennar) river. The average elevation of Bengalore is 920 m above the mean sea level. The Bengalore geographically located in the southern part of the Deccan plateau lies equidistant from the Arabian Sea and the Bay of Bengal. The highest point isVidyaranyapura Doddabettahalli, which is 962 metres
Geology: the peninin sular genissic complex(PGC) closepet granite dates back to 2500 m y the upper proterozoic dykes such as felsite, felsite prophyry and lamprophyre are the youngest intrusives and are dated at 800 m y
Minerals: Asbestos, clays, corundum, field spar, garnet, ochere, quartz and dimensional stones are the minerals present the region. Important commercial verities are present in the region.
geomorphology and geohydrology: the geomorphologically the area can be divided into uplands, platues and pediplains. The bengalore city on the situated in the trending high land with an average hight of 920 m above mean sea level. Forms a divide between the river arkavathi in the west and the Pinakini in the east. the major portion of the city is situated on the Hog back granite.
The hard crystalline rocks lack primary porosity. the weathered and fractured granite and genisis constitute principle aquifers in the area. the chief source of recharge is seasonal rainfall and seepage from rivers and reservoirs and tanks. Most of the area yeald 1-5 lts / sec
soil and land use: the soil is mainly red loomy and laterite. The land is classified into areable, fallow and pasture land and forest land, urban areas and waterbodies and marshy lands. Bangalore city represents urban agglomeration.
Geotechnical technical chracterers and natural hazards:
the bearing capacity of and fou ndation characteristic of rocks are good to very good. The greater part of the district falls under seismic zone I, the genisis high-grade schist intrusive from medium baring capacity of 500kg/ cm2 and their foundation capacity are good.
With a population estimated to be between 10,456,000 and 12,339,000,147 up from 8.5 million at the 2011census,84 Bangalore is a megacity, and the fifth most populous city in India and the 18th most populous city in the world.85 Bangalore was the fastest-growing Indian metropolis after New Delhi between 1991 and 2001, with a growth rate of 38% during the decade. Residents of Bangalore are referred to as “Bangaloreans” in English. People from other states have migrated to Bangalore. According to the 2011 census of India, 78.9% of Bangalore’s population is Hindu, a little less than the national average.83 Muslims comprise 13.9% of the population, roughly the same as their national average. Christians and Jains account for 5.6% and 1.0% of the population, respectively, double that of their national averages. The city has a literacy rate of 89%.87 Roughly 10% of Bangalore’s population lives in slums.88—a relatively low proportion when compared to other cities in the developing world such as Mumbai (50%) and Nairobi (60%).89 The 2008 National Crime Records Bureau statistics indicate that Bangalore accounts for 8.5% of the total crimes reported from 35 major cities in India which is an increase in the crime rate when compared to the number of crimes fifteen years ago.90 Bangalore suffers from the same major urbanisation The Bruhat Bangalore Mahanagara Palike (BBMP, Greater Bangalore Municipal Corporation) is in charge of the civic administration of the city. It was formed in 2007 by merging 100 wards of the erstwhile Bangalore Mahanagara Palike, with seven neighbouring City Municipal Councils, one Town Municipal Council and 110 villages around Bangalore. The number of wards increased to 198 in 2009. The Bangalore City Police (BCP) has seven geographic zones, includes the Traffic Police, the City Armed Reserve, the Central Crime Branch and the City Crime Record Bureau and runs 86 police stations, including two all-women police stations.
The city suffers significantly with dust pollution, hazardous waste disposal, and disorganised, unscientific waste retrievals.
While Ramprasad agrees with the BBMP’s plans to reconstruct the stormwater drains, the plan does not take into account the need to recharge the city’s groundwater instead of simply trying to funnel away rainwater, he says.
Bengalore lacks perennial river. The rulers of Mysore Kingdom and the local people constructed dams along the first and second order streams, thereby arresting the rainwater at a higher elevation and utilised this water for domestic and agriculture use(Harini Nagendra, 2010). These lakes compensated the absence of perennial rivers in the region. By infiltration and reduced runoff, the hydrological cycle was retarded. Due to unplanned urbanisation, most of the lakes in the higher altitudes of first and second order streams are lost or encroached(Tippaiah P., 2009).
The impervious surfaces increased the runoff and drastically reduced the infiltration thereby accelerated the hydrological cycle. The study area as shown in Figure 1, consists of a total geographical area of 742 Square kilometers. The geographic extent of Bengaluru lies between 77?24′ E – 77?48′ E longitude and 12?46′ N – 13?11’ N latitude, covering in Survey of India topographical Maps 57G8, 57G12, 57G16, 57H5, 57H9, 57H13 on 1:50,000 scale.