Bangalore city and Greater Bangalore: Bangalore 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 (Figure 1). Spatially Bangalore urban area has spatially increased from 69 sq.km (1901), 161 sq.km (1981), 221 sq.km (2001) to 741 sq.km (2006, Greater Bangalore). The decadal (2001 to 2011) population increase in urban India is 31.8% and in Karnataka is 31.5%. However, Bangalore witnessed dramatic decadal increase of 44%. The population has increased from 4.3 Million (Bangalore city in 2001) to 8.4 Million (in 2011, Greater Bangalore) and the population density has increased from 7880 persons per square kilometre to over 11330 persons per square kilometre. Bangalore receives an annual average rainfall of 750-850 mm. Bangalore located on the ridge with the topography undulating from 700 m to about 962 m AMSL. Taking the advantage of undulating terrain, earlier administrators of the region constructed interconnected water bodies (lakes/tanks) to meet the domestic and irrigation demand in the region. This is evident from historical records, Ganga rulers (870 AD) had constructed Agara, Bellandur and Varthur lake systems to facilitate irrigation, agriculture and other needs (District Gazetteer of Bangalore, Chapter 4, 214-215,http://gazetteer.kar.nic.in/gazetteer/distGazetteer). Similarly earlier sensible rulers had constructed and managed many lakes [Mayisandra (1245 AD), Ramasandra (1340), Allalasandra (1544 AD), Tippasandra (Anekal taluk- 1614 AD), Tirumalapura (1766), Mattikere (1834)] to sustain irrigation, domestic and other anthropogenic needs. Integrated lake management through regular desilting activities were also reported at Ramasandra Lake (1515 AD). The interconnected lake system in Bangalore also aided in transporting storm water from the city centre to outskirts. Bangalore City (spatial extent in 1980’s is 161 sq.km) had about 274 lakes and was aptly known as city of lakes, which helped in recharging groundwater resources, moderating micro climate, supported local livelihood (fish, fodder, etc.), irrigation and domestic water demand apart from recreation facilities.

Bangalore landscape with undulating terrain forms three major watersheds (Figure 1) namely Koramangala  and Challaghatta valley (K C Valley), Hebbal Valley and the Vrishabhavati Valley (V Valley). K&C valley is the largest catchment (255 sq. km.) in Bruhat Bengaluru (with spatial extent of 741 sq.km), followed by Hebbal valley (207 sq. km.) and Vrishabhavati valley (165 sq. km.). Interconnected lakes in KC and Hebbal valleys’ join at Nagondanahalli village (BBMP Ward 94 – Hagadur) and finally joins Dakshina Pinakin River. Interconnected lake systems in Vrishabhavathi valley joins Arkavathi River which is a tributary of the river Cauvery.

Figure 1: Location of KC-Valley (source: http://ces.iisc.ernet.in/energy)

Bangalore is experiencing unprecedented rapid urbanisation and sprawl in recent times due to unplanned unrealistic concentrated developmental activities. This has led to large scale land cover changes with the serious environmental degradation, posing serious challenges to the decision makers in the city planning and management process involving a plethora of serious challenges such as loss of green cover and water bodies, climate change, enhanced greenhouse gases (GHG) emissions, lack of appropriate infrastructure, traffic congestion, and lack of basic amenities (electricity, water, and sanitation) in many localities, etc.

Urbanisation and loss of natural resources (wetlands and green spaces):  Urbanisation during 1973 to 2017 (1028% concretization or increase of paved surface) has telling influence on the natural resources such as decline in green spaces (88% decline in vegetation), wetlands (79% decline), higher air pollutants  and sharp decline in groundwater table. Figure 1 depicts the unrealistic urban growth during the last two decades. Quantification of number of trees in the region using remote sensing data with field census reveals that there are only 1.5 million trees to support Bangalore's population of 9.5 million, indicating one tree for every seven persons in the city. This is insufficient even to sequester respiratory carbon (ranges from 540-900 g per person per day). Geo-visualisation of likely land uses in 2020 through multi-criteria decision making techniques (Fuzzy-AHP: Analytical Hierarchal Process) reveals calamitous picture of 93% (Table 1) of Bangalore landscape filled with paved surfaces (urban cover) and drastic reduction in open spaces and green cover. This would make the region GHG rich, water scarce, non-resilient and unlivable, depriving the city dwellers of clean air, water and environment

(Source: Ramachandra T V and Bharath H. Aithal, 2016. Bangalore’s Reality: Towards unlivable status with unplanned urbanisation trajectory, Current Science (Guest Editorial)), 110 (12): 2207-2208, 25 June 2016)

1028% increase in paved surface during 1973 to 2017

Solution: Enough is Enough, DECONGEST BANGALORE.

Bangalore is experiencing unprecedented rapid urbanisation and sprawl in recent times due to unrealistic concentrated developmental activities. This has led to the large scale land cover changes with serious environmental degradation, posing serious challenges to the decision makers in the city planning and management process involving a plethora of serious challenges such as climate change, enhanced emissions of greenhouse gases (GHG), lack of appropriate infrastructure, traffic congestion, and lack of basic amenities (electricity, water, and sanitation) in many localities, etc.

Figure 1: Land use dynamics in Bengaluru

Table 1: Land use dynamics of Bangalore - BBMP

Land use analyses carried using temporal (1970’s to 2016) remote sensing data shows an increase in built-up (paved surfaces; buildings, roads) from 5.39% (1973) to 89.56% (2016) with the decline in vegetation cover (92.3% to 8.94%), water bodies (1.05% to 0.26%) and other (open lands, agriculture) land uses (21.86% to 13.97%). There has been 1720% increase in concrete area during 1973 to 2016 with 68.6% loss of vegetation (Table 2). Predication of likely land uses reveals that 95% of the catchment would be concretised by 2020.

Table 2: Land use dynamics of V Valley

 
Figure 2: Land use dynamics in V Valley

• Ramachandra, T.V., Bharath, H.A. and Barik, B., Urbanisation Pattern of Incipient Mega Region in India, TEMA. Journal of Land Use, Mobility and Environment, 2014, 7(1), 83-100.
• Ramachandra, T.V., Bharath H. A.,and Durgappa, D. S.,  Insights to urban dynamics through landscape spatial pattern analysis, Int. J Applied Earth Observation and Geoinformation, 2012,18,329-343,.
• Ramachandra, T.V.,  Bharath, H. A.and Sreejith, K., GHG footprint of major cities in India, Renewable and Sustainable Energy Reviews, 2015, 44,473–495
• Ramachandra, T.V., Bharath, H. A., Vinay, S., et al., Trees of Bengaluru, ENVIS Technical Report 75, ENVIS, Centre for Ecological Sciences, IISc, Bangalore, 2014. 75p.
• Smart cities, Url: http://smartcities.gov.in/ (Last accessed on 20th May 2016)

Valley zones:  Bangalore has the distinction of having inter connected lake systems. Valley zones connecting two lakes are to be protected to ensure the continuation of hydrological functions of the drains and flood plains. These have been designated as sensitive regions as per the revised master plan 2015 (RMP 2015 of BDA). However, valley zones in Bangalore are being abused despite norms to protect these fragile ecosystems. Wetland ecosystem and valley zones have been experiencing threat due to the large scale catchment alterations with changes in the land use land cover. The region forms a part of primary valley, which is sensitive regions as per the revised master plan 2015 (RMP 2015 of BDA). The landscape forms an integral part of the protected area (as it is in valley zone) as per the CDP 2015. The alterations of these wetlands initiated by filling the low lying areas with excavated earth debris, followed by other construction activities. The land fillings have breached both rajakaluve and lakes. Major violations are:

Lakes (wetlands) have been aiding in recharging groundwater resources, moderating micro climate, supported local livelihood (fish, fodder, etc.), irrigation and domestic water demand apart from recreation facilities. Washing, household activities, vegetable cultivation and fishing are the regular activities in the lake for livelihood. Multi-storied buildings have come up on some lake beds intervening the natural catchment flow leading to sharp decline and deteriorating quality of water bodies. Unauthorised construction in valley zones, lakebeds and storm water drains highlight the weak and fragmented governance. This is correlated with the increase in unauthorized constructions violating town planning norms (city development plan) which has affected severely open spaces and in particular water bodies. Problems encountered by Bangaloreans due to mismanagement of water bodies in Bangalore are:

Due to the sustained influx of fresh sewage over the last several decades, nutrients in all lakes in the V. valley catchment are now well over safe limits. This valley has been receiving about ~45% of the city sewage for over last 70 years resulting in eutrophication. There are substantial algal blooms, Dissolved Oxygen (DO) depletion and malodor generation, and an extensive growth of water hyacinth that covers about 70–80% of the lake in the dry season. Sewage brings in large quantities of C, N and P which are responsible for eutrophication, profuse growth of macrophytes and algal bloom. The restoration and conservation strategies has to be implemented for maintaining the ecological health of aquatic ecosystems, aquatic biodiversity in the region, inter-connectivity among lakes, preserve its physical integrity (shorelines, banks and bottom configurations) and water quality to support healthy riparian, aquatic and wetland ecosystems. The regular monitoring of water bodies and public awareness will help in developing appropriate conservation and management strategies.