ENVIRONMENTAL STATUS OF POWAI LAKE, MUMBAI (INDIA)

Sengupta, M. and Dalwani, R. (Editors). 2008 Proceedings of Taal2007: The 12th World Lake Conference: 1650-1654

Environmental Status of Powai Lake, Mumbai (India) P.B.Salaskar1*, S.G. Yeragi 2 and Rodricks Gordon 1 1 Maharashtra State Angling Association, Powai Lake, Mumbai, India 2 K.J.Somaiya College of Comm. & Science, Mumbai, India *Corresponding author: email: [email protected]

ABSTRACT Powai lake (190 8' N and 720 54’ E) situated 55 meters above the mean sea level (msl) is known as 'Anglers Paradise’. It is meant exclusively for angling and sports and is located about 27 Km away in the north-east of Mumbai city, Maharashtra, India. The highly degraded water body represents a typical urban wet-land polluted by directly entering domestic sewage from the intensively urbanized catchments. The lake is extensively used for washing & bathing activities and exhibits characteristics of a eutrophicated ecosystem. In the present study the status of the Powai Lake was investigated & reported. The physical, chemical & biological characteristic of the lake was calculated with seasonal variations. The productivity status of lake was also estimated to understand the energy transformations. Based on the obtained statistical data, conclusions were made & appropriate recommendations were formulated to protect & conserve the Powai Lake. Some of the remedial measures for long term sustainability of the lake include: 1. Educating children about water-related issues is a beneficial long-term measure for achieving sustainable lake use. 2. Citizens and other stakeholders should be encouraged to participate meaningfully in identifying and resolving critical lake problems. 3. Security and patrolling of Powai lake 24 hours to prevent staling fish and other malpractices. 4. Greenery may be developed around lakes to prevent siltation. Key Words: Powai Lake, Eutrophication, Conservation

INTRODUCTION The lakes of our world are places of loveliness, pleasure & inspiration. They have inspired us, provided us with fresh water to meet our many needs. Although meeting increasing demands for water restoring and saving lakes from further threats will depend on non-structural solution i.e. rethinking the demands and current uses of lake water, and the river that flow into our lakes. The solution to present and future crises will not be found in new and extraordinary technological advances, instead they will be found through changing our attitudes and ways of using and managing water (Catley-Carlson, Margaret, 2001). Man has done modifications to the ecosystem to suit his needs which led to deterioration of the organisms. Even man has suffered from the change in the ecosystem. Numerous anthropogenic activities like disposal of sewage and industrial water, recreational activities, excess fertilization of lands and use of pesticides has threatened environmental health of both surface and ground water. Water pollution now a day is considered not only in terms of public health but also in terms of its conservation, aesthetics and preservation of natural beauty and resources. Water pollution has however threatened to reduce the quantity available in ponds, lakes, rivers and reservoirs due to disposal of sewage, industrial

water and due to other human activities (Trivedy and Chandrasekhar, 1999). Population explosion, industrialization, urbanization and developmental thrust of man have created these problems of water pollution. Wetlands, the precious natural resources are facing degradation all over the country. Deterioration of water quality, loss of biodiversity and fast depletion of water resources are the main challenges which need urgent attention. Though thorough study of all the wetlands in the country has not been done, several past studies on the subject give us the degree of deterioration of these resources (Kodarkar, 1999, Tekale & Kodarkar, 1999 and Diwan & Kodarkar, 2000). Deshmukh (1964) has studied the physicochemical characteristics of Ambazari Lake in Nagpur, Maharashtra. The water quality and conservation aspects of five water bodies in and around Hyderabad, Andhra Pradesh are discussed by Kodarkar, M.S. (1995). In the last two decades it has become a recurrent phenomenon in water bodies particularly in urban areas and linked to environmental degradation due to unprecedented urbanization and industrialization. (Kodarkar, 1995). Extensive limnological work of Powai Lake was carried out by a number of workers (Thakhare, 1969; Bhagat, 1977; Singh Kohili M.P., 1991). In the present study the status of the Powai Lake was investigated & reported.

the Powai lake in terms of 1. Reduction in total water spread and depth due to siltation, encroachment & reclamation (Fig. 2). Due to area development program considerable leveling of the hills around the Powai Lake has taken place, which resulted in the soil erosion considerably. Finally it leads to large scale siltation & sedimentation of the lake. It is estimated that 3000m3 of silt has been deposited in the lake. 2. Pollution from untreated domestic sewage entering the lake from settlements in the catchments areas. 3. Deforestation along the catchments areas of water resources results in increased run-off and soil loss. 4. Lack of sufficient skilled personnel and a strong institutional framework with political and legal status.

Figure 1. Map of Powai Lake Powai lake (190 8' N and 720 54’ E) (Fig. 1) situated in the metropolitan city of Mumbai, 55 meters above the mean sea level (msl). It is a man made lake built in 1891 and known as ‘Anglers Paradise’. It is meant exclusively for angling and sports and is located about 27 Km away in the northeast of Mumbai city. This lake came into existence in the year 1891, when Mumbai Municipality got constructed a monsonary dam of 10 meter height between two hillocks across Powai basin to conserve the rain water for drinking purpose, which later commonly known as Powai lake, since it impounded in Powai area. However, the water in the lake was found inpotable because of indiscriminate use of the lake for various purposes by the local people and also due to the addition of domestic sewage. This lake was open for the general utilization of the natives and it is leased out Maharashtra State Angling Association, Mumbai for angling in addition to conservation. The conservation of Powai Lake is in the interest of man as it’s ecological, aquacultural and tourist value. One of the most important steps in the conservation of the lake is to restore the water quality by controlling the pollution through different remedial measures. This lake has been included in the Central Government National Lake conservation Plan. So this lake which has been built before 100 years will change its form now. PROBLEMS More than 100 years old Powai lake represents a typical case of environmental degradation due to urbanization. The land in the catchments area was converted into development zone and a number of colonies have come up on it in the last 10 years. These developments have had an adverse impact on

Figure 2. Encroachment by builder lobby

RESULTS AND DISCUSSION From the very beginning, the water of the Powai lake was not meant for human consumption. With the increase in industrialization in the area, its water is being used by some of the industries in the area, e.g. Larsen & Tourbro. The lake’s water feeds one of the nullahs joining the Mithi River, which enters the sea at Mahim. Unfortunately for the beautiful lake, its catchments area, till very recently a ‘No development zone’ was released for real estate development under pressure from the powerful builders lobby. This will definitely affect the quality of the lake’s water and its future as a crucial water body in a congested metropolis. To meet developmental demands the mountains of Powai area have been cut, which resulted in loosening of soil in the area and finally entering into the lake system. It is estimated that till now about 3000m3 of silt has been deposited in the lake, as a result of which the bed of lake has raised up to one meter. Besides the silt, people from nearby slums also defecate and urinate near the lake. The lorry drivers are also increasingly finding the lake’s environs a good place to wash their vehicles. Importance of erosion and silting in the lake has been

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discussed by workers like Biswas, S (1977) and Kodarkar (1995). The other problem plaguing the lake is that of excessive growth of weeds like Ipomea and water hyacinth. These have choked a good portion of the lake, especially on the I.I.T., side. Algal and cyanobacterial cells are almost always present in the water body and can multiply extremely rapidly when the physical and chemical conditions are right. Powai Lake was said to be populated by 37 species of fish (Kulkarni, 1947) and Amore (1955) has listed 32 species in the lake while Singh Kohli (1991) has listed 10 main fish species i.e Catla catla, Cirrhinus mrigala, Tor khudree, Labeo rohita, Labeo calbasu, Osphronemus goramy, Hypophthalmichthys molitrix, Cyprinus carpio, Tilapia mossambica, Ctenopharyngodon idella in the lake. Although 10 species of sport fishes have been found in the lake, they are represented only in small numbers. The physico-chemical parameters studies clearly indicate that the main factor presumed to be responsible for the decline of fisheries in Powai lake are luxurious growth of aquatic weeds, aquatic pollution, high lead concentration, predation, over population of exotic species, low fertility, siltation. A lake has a Crocodile island with 10 to 15 crocodiles to boast of. Besides in the vicinity Hawks, Kingfishers, Cormorants, Wild Fowl, Cranes, Egrets and Turtles etc. are visible.

Productivity of an aquatic ecosystem fully depends on the physicochemical factors. The physico-chemical factors never remain stable for prolong period, but show fluctuation from region to region. The range of physico-chemical parameters associated with the water quality is presented in Table 1. It is observed that in the last few years there is not much change in the water quality as reported by earlier workers (Thakhare, 1969; Bhagat, 1977; Singh Kohili M.P., 1991).

Figure 3. Community Awarness

Table 1: Comparative Report of Minimum-Maximum Range of Physico-Chemical Parameters of Powai Lake (Present and Earlier works) SR. NO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

PARAMETER Depth (M) Transparency (Cm) Temp. (0C) (a) Ambient (b) Water pH Total Alkalinity (mg/l) Total Hardness (mg/l) Carbon dioxide (mg/l) Dissolved Oxygen (mg/l) Total Solids (mg/l) Chlorides (mg/l) Dissolved Organic matter (mg/l) Phosphate (mg/l) Silicates (mg/l) Silica (mg/l) Pri. Productivity (a) Gross (mg/c/m3/day) (b) Net Turbidity (ppm)

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1961-63 (By Thakhare-1969) Min Month Max N.A. N.A. 32.00 JUNE 74.00 14.00 JAN 34.00 23.20 JAN 30.00 7.20 JUN 7.80 N.A N.A 58.60 SEP 100.00 4.00 MAR 7.80 2.80 JUN 7.80 N.A N.A N.A N.A N.A N.A 0.02 AUG 0.40 N.A N.A N.A N.A N.A N.A N.A N.A N.A N.A

Month SEP OCT MAY SEP JUN JUN AUG JUL -

1975-77 (By M.J.Bhagat-1977) Min Month Max 5.13 MAY 6.70 45.00 MAY 75.00 28.00 FEB 32.00 22.80 FEB 30.60 7.20 MAY 7.80 50.00 FEB 86.00 52.00 AUG 92.00 2.20 SEP 14.60 4.00 MAY 12.40 N.A N.A N.A N.A 4.00 FEB 12.60 0.02 AUG 0.08 0.02 AUG 0.20 N.A N.A 420.00 MAY 1380 100.00 MAY 750.00 N.A N.A

Month SEP FEB MAY MAY FEB MAY MAY MAY FEB MAY APR DEC FEB FEB -

SR. NO 1 2 3

PARAMETER

1987-89 (Project report by –C.I.F.E) Min Month Max Month 1.00 MAY 6.20 SEP 28.00 JUN 120.00 SEP 27.00 JAN 35.50 MAY 25.00 JAN 34.00 MAY 6.70 MAY 7.80 SEP 70.00 AUG 167.00 DEC 65.00 AUG 132.00 MAY APR,MAY N.A. 20.00 JAN JUN SEP FEB,JUN 3.60 NOV 12.00 AUG SEP

1995-96 (By Salaskar, P.B.-1998) Min Month Max Month 2.65 JUN-96 6.0 SEP-95 51.25 JUN-96 97.25 OCT-95 23.67 FEB-96 31.52 MAY-96 23.63 FEB-96 31.50 MAY-96 8.13 APR-96 7.13 AUG-96 81.25 MAY-96 141.00 OCT-96 104.00 JUN-96 171.00 JUN-96

4 5 6

Depth (M) Transparency (Cm) Temp. (0C) (a) Ambient (b) Water pH Total Alkalinity (mg/l) Total Hardness (mg/l)

7

Carbon dioxide (mg/l)

8

Dissolved Oxygen (mg/l)

9

Total Solids (g/l)

3.00

NOV

17.00

10 11 12 13

Chlorides (mg/l) Dissolved Organic matter (mg/l) Phosphate (mg/l) Silicates (mg/l) Silica (mg/l)

22.00 N.A N.A N.A N.A

AUG -

14

Pri. Productivity (a) Gross

430.00

OCT

(mg/c/m3/day)

312.50

15

(b) Net

Turbidity (ppm)

N.A

OCT DEC -

&

REMEDIAL MEASURE *Some of the remedial measure for long term sustainability of the lake includes: 1. Educating children about water-related issues is a beneficial long-term measure for achieving sustainable lake use. 2. Environmental education centers located adjacent to wetlands, rivers & other natural features enhance public awareness of the feature. (Fig. 3) 3. Citizens and other stakeholders should be encouraged to participate meaningfully in identifying and resolving critical lake problems. 4. Security and patrolling of Powai Lake 24 hours to prevent stealing fish and other malpractices. 5. Development of lake environs as a recreational zone by developing gardens, parks and introduction of water sport 6. Construction of a boundary wall after proper survey to prevent further encroachment. 7. Reducing the pollution of the lake and improving the water quality by Disiltation, BioRemediation , By through various measures such as flap gates, construction of dhobi ghats and toilets, watershed management techniques, etc. REFERENCES Amore, D.L. (1955): ‘Powai” Hind Kitab Ltd. Publisher, Mumbai

1.10

JUN-95

5.55

JUL-96

3.60

JUN-95

6.31

AUG-96

JUN

85.00

AUG-95

120.00 N.A N.A N.A N.A

JUN -

25.99 N.A 0.32 N.A 3.06

OCT-95 NOV-95 JUN-96

45.00

AUG

600.00

DEC-95

AUG

300.29

DEC-95

-

2.28

MAY-96

3300.0 0 N.A

295 mg/l 58.48 N.A 0.67 N.A 27.00 4324.3 3 3337.0 0 7.90

JUN-96 JUN-96 JUN-95 JAN-95 SEP-96 SEP-96 JUN-95

Bhagat, M. J. (1977): “Ecology and Sport Fishery of Freshwater Lake”, M.Sc. Thesis, Univ. of Mumbai, Mumbai Biswas, S. (1973): Limnological observations during the early formation of Volta lake in Ghana, Man-made lakes their problems and environmental effects. Ed. By W. C. Ackermann. G.E. White. Catley-Carlson, Margaret. (2001): Abstract-9th International Conference on the Conservation and Management of Lakes, 12-15, Nov. 2001, Biwaka, Japan. Deshmukh S.B. (1964): Physico-chemical characteristics of Ambazari lake water. Nagpur, Maharashtra Ind. J. Environ. Hlth 6(3): 166-168. Diwan, A.D. & M.S. Kodarkar (2000): Wetlands are not wastelands. Souvenir of Nat. conference on Wetlands – Ecology, Economy and Sustainability, 29-30, October 2000 at S.K.R. college for women, Rajahmundry, Andra Pradesh, pp. 31-33. Kodarkar, M.S. (1995): Conservation of lakes, IAAB publ. No. 2, IAAB, Hyderabad pp.82. Kodarkar, M.S. (1999): Conservation of water bodies in urban areas. Souvenir of Nat. conference cum workshop on wetland conservation. Problems, prospectus & challenges in next millennium, 23-25, October 1999 at R.A. Arts, M.K. Comm. & S. R. Rathi Sci. College, Washim, Maharashtra, pp. 2637. Kulkarni, C.V. (1947): Note on Freshwater Fishes of Bombay and Salsette Islands. J. Bombay Natural History Society, 47(2): 319-326. Singh Kohili M.P. (1991): Final project report of studies of Hydrobiology and Fisheries of Powai lake, Mumbai. Tekale, N.S. and M.S. Kodarkar (1999): Idol immersion in Masunda lake, Thane city, Maharashtra- A critical

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analysis and remedial measures. J.Aqua. Bid, 14 (1&2):115-117. Thakhare, V.P. (1969): “Some aspects of limnology of Powai Lake, Mumbai”. M.Sc. Thesis, Univ. of Mumbai, Mumbai. Trivedy, R.K. and Chandrasekhar T.R. (1999): Sediment Characteristics of freshwater bodies, Manglore, Karnataka. J. Ecobiol, 11(1): 59-64.

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