CONTENTS-
Abstract
Introduction
Role of Water Bodies in Urban Areas
Study Area
Conclusions
Acknowledgements
Bibliography

Water tanks of Bangalore primarily established for agricultural and domestic purposes over two centuries ago, has   now become a prominent component in the urban landscape of the city. The reduction in number of water bodies in Bangalore urban area has been a matter of concern for the past few years. The need to restore these water bodies for their various beneficial roles in the city is realised. The aim of the study was to project the trends in urban development around the water tanks of Bangalore, which would guide in planning restoration measures for existing tanks.

A chronological development of the Bangalore urban area and its impact on water tanks was mapped for different years spanning over a period of five decades. The various maps used for the study were,   Bangalore map 1806, Bangalore cantonment maps for the years 1924, 1935 and topographical maps published by Survey of India for the years 1969 and 1980. The temporal changes in the area and the physical status of the water bodies for each of the above mentioned years was methodically mapped and recorded. Significant observations regarding water bodies related to surrounding urban development was noted down.

The analysis of these observations over the period showed that most of the tanks were lost to urbanisation due to transportation network, cultivation, sewage disposal and siltation of tank beds. Four stages of development that led to the loss of water bodies were also identified under each issue.

Identification of present status of an existing water body in the process of the developmental trend would lead to guidelines for restoration activities of that particular water body.

The absence of any kind of perennial surface water source around the Bangalore region led to the construction of several water tanks. These tanks were constructed after identifying the natural valleys and constructing weirs across these valleys. The tanks stored runoff water during monsoons, to be used during lean period. Being situated in the same catchment area the tanks formed chains that were also dependent on surplus water from the tanks on higher elevation apart from the runoff from their catchment. The impounded water was mainly used for irrigation and domestic purposes in the lean seasons. As the city developed and various other means of water were augmented, the direct dependency on the tanks as a source of water declined and a change in the role of water bodies was observed. These tanks having been established for over two centuries play a vital role in the environmental conditions of the city.

The role of water bodies that has changed due to urbanisation can be seen under the following heads:

Ecological role:

Over the years the manmade water bodies have acquired the status of wetlands, where the wetland ecosystem thrives and has become a significant ecological asset   to the city.

Hydrological role:  

These structures play an important role in checking flash floods due to heavy rains in low-lying areas. They act as sediment trap and reduce erosion by regulating runoff. The flash flood observed in the Koramangala area during every monsoon is very much due to breaching of tanks on   the higher elevation.

Climatological role:

The water bodies influence the microclimate of their surroundings to a large extent. They cool the hot winds, minimise back radiation, regulate humidity level, maintain soil moisture and keep the surface cool. The drastic reduction in the water spread area due to urbanisation has been one of the reasons for the increase in the mean annual daily temperature by 1.2 degree centigrade (Gazetteer of India) over the past three decades.

Recreational role:

The water tanks and its adjacent areas are utilised for various recreational activities such as parks and gardens on the tank edge, water sports and boating in the tanks. Various bird watching clubs have emerged whose favourite haunt is the water tank areas for observing wetland birds. (Krishna.M.B, 1996)

Economic role:

Economic benefits can be obtained through cultivation, fisheries and recreational activities, which   help in maintenance of the tank.

Role in integrating the landscape structure of the city:

The water bodies become landscape units in the landscape structure of the city. The drains that connect these water bodies penetrate into the dense urban fabric and have the potential to integrate the landscape structure. They link the tanks and the open spaces along them and can have movement corridor running beside them.

Relevance of study

The rapid urban development with little concern for its natural resources has resulted in the loss of   many tanks in the city. The city of Bangalore has few planned open spaces on regional scale and the water tanks are the only large open spaces remaining in the conurbation area. The need to conserve these tanks for their various benefits is realised. To provide an effective restoration and conservation guidelines for the tanks, it becomes essential to see the process through which various tanks have been lost and identify those that are under   threat   due to urban development.

The area of study was restricted to the extent on the Bangalore guide map for the year 1969   (Scale= 1: 20,000), which covers   an area of   400 sq kms.   The study area is situated at an average elevation of 900 m above mean sea level.

The various milestone events concerning urban development of the region and the significant observations with respect to water bodies from the maps for various years are as mentioned below.

Bangalore, being a part of the Deccan Plateau represents   plains, hills, valleys and undulating terrain, which is unique to this metro.

The main ridge running along NNW – SSE divides the area into two distinct topographical regions.

•  The steep sloped and the undulating terrain that lies west of this ridge and belongs to the Arkavati river basin.

•  The area east of the main ridge has gentle slopes   characterised by various valleys emerging from the ridge. This area falls under the Pinakini river basin.

This topography exhibits a radial pattern of drainage, distributing from the apex and ramifying to the lower plains with dentric and reticulate drainage pattern. The drainage pattern of the city is governed mainly by three drainage systems namely, the Vrishabhavati system that drains most of the central and south western parts of the city, the Bellandur system that drains the southern and the south eastern waters and the Hebbal system which drains the north eastern parts of the city.

OBSERVATIONS:

Significant numbers of tanks are present between the 900 to 880 MSL contour levels and to the east of the ridge due to its gentle topography.

MILESTONE EVENTS:

1537:Magadi Kempe Gowda (Yelahanka Line of Chiefs ) established the settlement of Bangalore (Bengaluru) with a fort of modest dimensions and mud as the main building material.

1605:Magadi's son Kempe Gowda II expands the fort and demarcates the limits of Bangalore through 4 decorated pillars, still standing today. This encompassed about 25 sq. km. of land to indicate a 4 century old vision of   Bangalore. It was during the reign of these rulers that the tanks were built for agricultural and domestic   purposes.

1759:In about 10 ha of land around the Kempe gowda Pillar, Hyder Ali expands an existing mango orchard into a garden and named it Lal - Bagh. It was during Tipu's (Hyder's son) time many floral species were brought   from Turkey, Afghanistan, Persia and Mauritius to Lal – Bagh .

OBSERVATIONS:

The first settlement was established along a main ridgeline that took advantage of the higher elevation as well as the spatial enclosure due to topography. Early settlers took advantage of the natural valleys to build a series of tanks that stored the rainwater and served   the water needs of the surrounding population. Smaller settlements were distributed mainly next to the water tanks. The tank was usually named after the settlement around it, for e.g. Koramangala tank. Dry crops like Ragi and maize were predominant cultivated crops. However, rice cultivation was seen in the command area or the atchkut due to its high water requirements.

MILESTONE EVENTS:

1809:The British Cantonment was established near Ulsoor tank covering a large area along with a buffer space between the cantonment and the old city.

1831:Shift of British capital from Mysore to Bangalore.

1864:Bangalore connected by rail to Chennai to become second most important commercial centre.          Cubbon park laid out on 120 ha of land. Racecourse is built outside the western limits of the cantonment.

1866:A new reservoir – Miller's tank is built to supply piped water in addition to the water from Ulsoor.

1882:Sankey tank is constructed near K.G. Northern Pillar.

1887:Wodeyars build the Bangalore palace on spacious grounds.

1896:Hesaraghatta reservoir commissioned to augment protected water to the city.

OBSERVATIONS:

Cantonment established on gentle topographical area and occupied vast area of land. It was inevitable   that development takes place on the southern and the eastern areas (though they had steeper slopes) due to its proximity to the old city and the cantonment. The transportation network that was developed treated water bodies as islands with embanked roads all around. Since 1896, protected water was augmented, the dependency on the tanks for water decreased drastically and hence led to their neglect. The storm water drains and the sewer lines were along the natural valleys and   drains, the two serving as one in many places, which finally drained into a   tank along its path. The Koramangala   and   Chalaghatta valley drained most of the old city area and the cantonment. Since the sewers also opened into these drains, certain tanks, which previously were seasonal water bodies, now contained water all year round, for eg: Koramangala and Bellandur tanks.

MILESTONE EVENTS:

1931:Population of Bangalore enumerated as 3.08 lakhs.

1933:The Tippegondanahalli dam across the Arkavati river brings treated water into the city.

OBSERVATIONS:

The growth of the civil and military stations was observed. The civil station growing on the south and east on a grid iron pattern, for e.g. Basavangudi, Malleshwaram. The civil station also grew towards the cantonment area. The military station growing within it's boundary, with its density increasing, for e.g. Cox   Town and Cleveland Town. The British brought the concept of recreational spaces like the polo, golf, turf clubs, the racecourse, etc. For the need of large and relatively flat ground for these sports activities, most of these were laid on dry tank beds. For e.g. Part of Ulsoor tank and Domlur tank. Darmambudhi and Shule, and Sampangi tanks were used as playgrounds. The Cubbon park, race course, golf course and the palace grounds together formed a green buffer along the western edge of the cantonment. Koramangala was breached and the tank bed used for cultivation as a vegetable garden.     

MILESTONE EVENTS:

1941:Population of Bangalore enumerated as 4.07 lakhs.

1949:Bangalore Municipal Corporation formed by merging the city and cantonment areas. It encompassed 175-sq. km. of land.

1952:Five satellite towns proposed, namely townships of H.A.L., I.T.I., H.M.T., Banaswadi and north of Tannery road,   within a short time these areas get merged with Bangalore.

1964:Bangalore Water Supply and Sewerage Board (BWSSB) constituted.

OBSERVATIONS:

Rapid industrialisation and migration with the setting up of public sector industries. The city grows in the Northeastern and southern direction engulfing the tanks that comes across them. The city planners realised the need to protect the water bodies and the conservation of Sankey tank, Hebbal tank, Nagavara Tank, Chellaghatta tank, Bellandur tank, Madivala tank, Sarakki and Kempambudhi tanks were proposed. (Master Plan 1965) Construction activities and reduced vegetative cover on catchment areas led to siltation of the Hoshallikere and the tank becomes a marshland.

6. CHRONOLOGICAL STUDY - BANGALORE, AD 1980

MILESTONE EVENTS:

1971: Population enumerated as 16.64 lakhs. Land values in the cantonment area begin rising.

1972:Government approves the Out line Development Plan for Bangalore.

1974:Cauvery Water Supply Scheme brings treated water to Bangalore.

1976:Bangalore Urban Arts Commission (BUAC) set up. Work commences on Comprehensive Development Plan or enlarged metropolitan area of 1279 sq. km. of which 830-sq. km. is the green belt.

1981:Population of the enlarged Bangalore Urban Area enumerated as 29.22 lakhs. Decadal growth rate is highest among 12 metropolitan cities.

1988:Electronic city developed on 140 ha of land on Hosur road. The city emerges as the software centre of India.

1991:Poulation of BUA enumerated at 41.3lakhs. This constitutes 9.2% of the total population of the state and 30%   of the total urban population of the state.

1995:Revised CDP approved for BMA for population of 70lakhs by AD 2011with a conurbation area of 565sqkms and green belt of 714 sq kms.

OBSERVATIONS:

Rapid urban development with little concern to save the water bodies. Most of the water bodies in the city are surrounded by developed land and the ones on the fringe areas are encroached   for residential development. Increase in the nutrient content of tank water due to sewage disposal and increased erosion rate due to construction boom resulted in rapid siltation in down stream water bodies creating marshlands. The Hoshalli marshland has ceased to exist since its drain bypasses the tank and has no other source of water. It becomes an open ground prone to urban development.

The temporal changes in the area of the tanks and their physical status were recorded. These were tabulated along with the status of tanks as in Laxman Rau Committee Report 1986.

The analysis concludes the study of the chronological development of the city of Bangalore over a period of five decades (1924-1980). The area of urban growth in 1940 was 175 sq kms as compared to 281 sq kms in 1985 and 524 sq kms in the proposed comprehensive development plan.

The conclusions with respect to the various aspects of the tanks are given below:

LOCATION OF TANKS:

The urban expansion in five decades is less than double but the tank area engulfed by development is four times its area from what it was five decades earlier.

WATER SPREAD AREA:

There has been a reduction in the waterspread area by 50%. 15% of the total waterspread area have turned to marshland over the past five decades, which   was 33 % of the waterspread area in the year 1980.

STATUS OF TANKS:

50 % of the tanks are either developed, have become open space or marshlands.  

STATUS OF TANKS INSIDE URBAN DEVELOPMENT:

60 % of the tanks have been utilised or encroached upon for urban development, or have become open spaces serving as play grounds for the neighbouring population or are marshlands.

STATUS OF TANKS ON THE PERIPHERY OF URBAN DEVELOPMENT:

3.5 times increase in the marshland area with in a span of four decades. This sums up to 42 % of the total tank area in the periphery. This rapid deterioration of the tanks is due to siltation caused by upland erosion and   eutrophication in the water bodies.

TREND IN URBAN DEVELOPMENT AROUND WATER TANKS:

The maps and the tabulation were   analysed which revealed the trend in urban development. Four issues can be identified under four stages of development around the tanks. (Ref fig 1.)

• i. Transportation network:

Stage I: Healthy tanks.

Stage II: Reduced vegetative cover in the catchment, some catchment area altered and minor roads observed around the tank.

Stage III: The tanks become more as   traffic islands as the roads carry major traffic. It goes dry   over a period of time and transportation cuts across the tank bed. The dry tank bed is      used as play ground by the   neighbourhood.

Stage IV: The tank is now at a significant location with respect to the urban development. The dry tank bed   is allotted for public amenities like sports stadium for the need of large area in the city centre.

• ii. Cultivation:

Stage I: Healthy tank with rice cultivation in its Atchcut region.

Stage II: The tank bund is breached for the need of cultivable land close to the city. Tank beds are fertile    for cultivation and ground water is used for irrigation.

Stage III: Stress due to urban development force cultivation to move down stream in the valley and the tank    bed becomes vacant land.

Stage IV: Institutional and residential layouts are proposed on the tank beds.

• iii. Sewage disposal:

Stage I: Healthy tank.

Stage II: Residential layouts open their sewers into the natural drain, which increases the water spread area. The water quality deteriorates and become mosquito breeding grounds.

Stage III: The tank bund is breached under the malaria eradication programme. Encroachments start on the    dry tank bed.

Stage IV: Layouts come up on the breached tank bed with small area left as open space.

• iv. Siltation:

Stage I: Healthy tank with cultivation on the Atchcut area.

Stage II: Extensive construction activities on upstream lead to high erosion. This resulted in siltation in down stream tanks.

Stage III: Silted water bodies become marshlands. These remain as open space for few years.

Stage IV: Lack of water to the marsh results in its drying up. This dry tank bed is now considered suitable   for construction and layouts are proposed on these.

The study showed that many of the existing water bodies face a threat due to one or more of the above issues. Hence it is essential to identify the issues concerned, its stage in the process of developmental trend and propose appropriate measures for a particular tank.

The author wishes to thank the following individuals for their valuable guidance during the above study: Prof. M.Shaheer, Head of Department, Department of Landscape, S.P.A, New Delhi. Dr.Karanth, Head of Department, Sociology unit, Institute for Social and Economic Change, Bangalore. Prof. Gauhar Mehmood, Geologist, S.P.A, New Delhi.

•  Comprehensive development plan (revised) 2001, Report by Bangalore Development Authority.

•  Environmental management plan for Bangalore (2001), Department of Environmental planning, S.P.A.

•  Lakes for Bangalore water needs – Beautification and pollution prevention (1997), Aranya Bhavan.

•  Master plans 1965 and 1985, Reports by Bangalore Development Authority.

•  Krishna. M.B (1996) Report on Annual water bird census in and around Bangalore and Maddur.

•  Report of the expert Committee for the preservation of tanks in Bangalore (1986)

•  Srinivas T.S (1996) Report on Status survey of lakes in and around Bangalore and Maddur.

•  The Encyclopaedic District Gazetteers of India - Bangalore District.

Department of Architecture,
Siddaganga Institute of Technology,
Tumkur – 572 101,
Karnataka, India.