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Powai lake

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  • 1. POWAI LAKEPowai Lake (named after Framaji Kavasji Powai Estate) is anartificial lake, situated in the northern suburb of Mumbai, in thePowai valley, where a Powai village with cluster of huts existed.The city suburb called Powai, shares its name with the lake.Indian Institute of Technology, Bombay one of the premierinstitutions of science and technology in India is located to theeast of the lake.[1] Another famous institution, the NationalInstitute of Industrial Engineering (NITIE) is also located close tothe lake. Housing complexes and plush hotels are developed allaround the lake periphery. Population around the lake has thussubstantially increased over the years.When it was built, the lake had a water spread area of about2.1 square kilometres (520 acres) and the depth varied fromabout 3 metres (9.8 ft) (at the periphery) to 12 metres (39 ft) atits deepest.The Powai Lake has gone through many stages of water qualitydegradation. The lake water which used to supply to Mumbaifor drinking water has been declared unfit to drink. The Lakestill remains a tourist attractionThe Powai Lake has gone through many stages of water qualitydegradation. The lake water which used to supply to Mumbaifor drinking water has been declared unfit to drink. The Powai Follow me on www.webbieguru.blogspot.com
  • 2. Lake has gone through many stages of water qualitydegradation. The lake water which used to supply to Mumbaifor drinking water has been declared unfit to drink. The Lakestill remains a tourist attraction. HISTORYA stream tributary of Mithi river, which served the Powaivillages water supply needs, was dammed in 1891, during theBritish period, initially to augment water supply to the thenBombay city (now called Mumbai), by constructing two dams of10 m height each to store the rain waters flowing from thelower slopes of the Western Ghats and streams from theeastern and northeastern slopes of hills.[4] It was planned as anantiwater famine measure, to the southeast of Vihar Lake (amuch larger lake) also for water supply to Mumbai city.Before the lake was built by the British, in the year 1799 A.D.,the estate where the lake is now located was leased on a yearlyrent to Dr. Scott and after his death in 1816 A.D., thegovernment took control of the estate in 1826 A.D., and leasedit once again to one Mr. Framaji Kavasji, a Parsi merchant, afterwhom the lake was named when it was built in 1891.The drinking water supply objective of the lake was abandonedin the early 1990s, in view of poor quality of the water stored,caused due to pollution, water hyacinth and weeds, untreated Follow me on www.webbieguru.blogspot.com
  • 3. sewage and large silt deposit. The lake was, therefore, leasedout to the Western India Fishing Association, a quasigovernment organisation who used it for both fish culture andangling. Later, the Bombay Presidency Angling Association wasformed in 1936 and later in 1955, under the SocietiesRegistration Act 1860, it was registered as “The MaharashtraState Angling Association” (MSAA) and the lake is now undertheir control. Realising the gravity of the environmentalpollution of the lake, the MSAA has revised its constitution,to actively care for, clean, develop, maintain, and beautify theEnvironment at Powai Lake.MSAA is now involved with a) removal of water Hyacinthinfestation, b) supporting research with Fisheries Dept.forconservation of the Indian Mahaseer, c) Water quality analysisd) and augmenting security. ACCESSThe lake is about 40 kilometres (25 mi) from Mumbai by roadand is approached via Kings Circle, Sion, and Kurla or throughSanta Cruz and Andheri.[6] Kanjurmarg on the central main lineof the Mumbai Suburban Railway is the nearest railway stationto the lake. HYDROLOGY AND WATER QUALITY Follow me on www.webbieguru.blogspot.com
  • 4. It is reported that the average rainfall at Powai is about 2,540centimetres (1,000 in), and the lake overflows for about forsixty days each year. The overflow from the lake flows into theMithi River. Silt studies conducted in 1995 estimates that 4500lakh cubic metres of silt has been deposited in the lake since itsconstruction.[2] It supplied two million gallons of water toBombay (now Mumbai) when it was built. Following theconstruction of the Tansa dam and creation of the reservoir, in1892, Powai waters were used for irrigation.[7] The lake drainsa catchment of 6.61 km2 (part of the Powai-Kanheri hill rangeswhich also drain into the adjoining Vihar Lake and Tulsi Lake).The dam, built in stone masonry has a height varying from 3 mto 6m with top level of the dam kept at E.L. 58.5 m (with Townhall datum).[8] Government of Maharashtra reports that due toeutrophication of the lake water from untreated sewage andgarbage from nearby residential and slum colonies, the lake Follow me on www.webbieguru.blogspot.com
  • 5. water is unfit for drinking water use. Hence, the lake is nowused for recreation, gardening, cattle washing and fishing. Thewater of the lake is also supplied to Aarey colony and L&T fornon domestic uses. Dissolved Oxygen (DO) level at the bottomof the lake is reported to be 0.71 mg/litre and at surface 4.11mg/litre, average value of pH is 7.2 and COD is 42.70 mg/litreon the surface and 119 mg/litre at the bottom of the lake. LAKE REJUVENATIONAppreciating the problem of silting, growth of water hyacinth,weed, and eutrophication of the lake, the IIT Bombays Class of1980 launched a "Revitalization of Powai Lake” with theobjective of restoring the lake to its original pristine andsustainable form by adopting Eco-friendly designs and materialsfor the restoration works.Some of the tasks proposed to be undertaken with the fundsdonated by IIT, Bombay included:• Removing water hyacinth and weeds from the lake in partsnearest to the campus• Starting a publicity and an awareness program in the area• Building embankments, walkways and pathways to the lake• Constructing a large gazebo for an evening (or morning orafternoon) by the lake Follow me on www.webbieguru.blogspot.com
  • 6. • Planting trees, and creating a garden• Installing docks, deploying boats and canoes• Allocating funds for annual maintenanceThe project was proposed to be professionally managed with aproject manager working under directives of IIT Bombay withan “Oversight Committee“ to monitor objectives set for therestoration work.In 1995, the National Lake Conservation Plan (NLCP) of theMinistry of Environment and Forests (MoE&F),Government ofIndia, reviewed the condition of Powai Lake and included theLake in its list of ten major lakes in the country for revival andimprovements. The restoration/revival programme, fullyfunded by the NLCP, was launched in April 2002, andimplemented by Bombay Municipal Corporation (BMC) nowcalled Brihanmumbai Municipal Corporation (BMC), theGovernment of Maharashtra and as a result the status of thelake has undergone a major shift from the hypertrophiccondition to mesotrophic condition by adopting a noveltechnique of aeration and bioremediation. This has resulted inthe lake being used for fishing and recreational purposes. Temperature Follow me on www.webbieguru.blogspot.com
  • 7. The water temperature varies with the atmospherictemperature i.e. being maximum during summer i.e 35ºC andminimum during winter i.e 22ºC. pHAs per pH value is concerned, it was found that throughout themonth slightly lower values during monsoon season and slightlyhigher values during winter, but throughout the mo nth itremained slightly alkaline. Dissolved OxygenDissolved Oxygen content in Powai Lake was found to be verylow throughout the month. DO content ranged from 0.2 to 4.4mg/l indicating the anaerobic conditions in the lake water. Thisindicates low rate of primary production in aquatic ecosystemof lake. Minimum amount required for optimum fishpopulation may be as high as 5 to 8 mg/L. The oxygen depletingsubstances reduce the available DO. According to Trivedy andGoel (1 986) reported that low oxygen concentrations areassociated with heavy contamination by organic matter. NitrogenDuring the investigation nitrogen content was found to bevaried from april to September.High level of nitrogen in lakecan be due to lack of oxygen at the bottom of the lake. Follow me on www.webbieguru.blogspot.com
  • 8. ConductivityConductivity was higher in summer months due to theincreased concen tration of salts which would have beencaused due to evaporation during that season. The conductivityranged from 360 to 810 Mmhos/cm. ChlorideThe Chloride concentrations of Powai Lake during the studywere found to be below the permissible limit. Chlorides arepresent in water as Sodium chloride, Magnesium chloride andCalcium chloride.Although they are not harmful as such, theirconcentration over 250 ppm imparts a particular taste to thewater rendering the water unacceptable for drinking purposes.Existence of unusually high concentration of chloride in lakeindicates pollutants from domestic sewage and industrialeffluents and thus leads to eutrophication. In addition to thatsalinity was also calculated which too shows increase in duringsummer season and decrease in monsoon season. MAJOR CAUSES OF DETERIORATION OF LAKE o Uncontrolled development and unauthorized quarrying activities in the catchments area. o Ingress of untreated sewage from the residential areas. Follow me on www.webbieguru.blogspot.com
  • 9. o Dumping of garbage and other waste materials in the lake. o Washing of clothes, vehicles, open defecation etc. On the lakeshore. DESILTING PROJECTThe Lakes water depth is reported to have reduced to as littleas 0.33 metres (1.1 ft) at some locations, on account of thelarge inflow of sewage, domestic waste water and silt fromsurrounding residential and industrial areas.Brihanmumbai Municipal Corporation (BMC) has thereforeplans to desilt the Powai Lake at a cost of US $9 million. FAUNA Follow me on www.webbieguru.blogspot.com
  • 10. Large number of crocodiles on the lake side have been sightedon the shores of the lake and also reported by fishermen andofficials of IIT, Powai.White throated kingfisher, small blue kingfisher, spot-billedduck, spotted dove, a few purple moorhens, purple rumpedsunbirds, bronze winged and phaesant tailed jacanas, ashyprinias, brahmany kite, Red vented, red whiskered and whitebrowed bulbuls, cormorants, lesser whistling ducks, grey,purple and pond herons, little, Follow me on www.webbieguru.blogspot.com
  • 11. intermediate and large egrets,, perigrine falcon, greater coucal,rose ringed and Alexindrine parakits, Eurasian marsh harrier(possibly winter visitor), wooly necked stork (winter visitor)hopooe & whiskered terns. butterflies, honey bees, bumblebees and beetles have also been sighted. FLORABalsam bushes, in their full bloom, in pink-purple color are seenaround the lake periphery, like a carpet.Powai Lake is an artificial lake, situated in the northern suburbof Mumbai. The lake was created in 1891 by constructing dambetween two hillocks across Mithi River. Catchment area of thelake is about 600 hectors and water spread area at full supplylevel is 220 hectors. The lake water is used for non-potablepurposes i.e. gardening and industrial use. Follow me on www.webbieguru.blogspot.com
  • 12. In recent times, 40% of the lake has disappeared. The lake hasdeteriorated due to accelerated growth of residential,commercial and industrial area around the lake. The untreateddisposal of sewage and garbage from nearby residential andslum colonies have affected the quality of the water.Dissolved Oxygen level at the bottom of lake has gone low as0.71 mg/ltr, and at the top it is 4.11mg/Ltr. The catchment ofthe lake has also been affected badly due to unplannedquarrying activities.Appreciating the problem of silting, growth of water hyacinth,weed, and eutrophication of the lake, the IIT Bombays Class of Follow me on www.webbieguru.blogspot.com
  • 13. 1980 launched a "Revitalization of Powai Lake” with theobjective of restoring the lake to its original pristine andsustainable form by adopting Eco-friendly designs and materialsfor the restoration works. In 1995, the National LakeConservation Plan (NLCP) of the Ministry of Environment andForests (MoE&F), reviewed the condition of Powai Lake andincluded the lake in its list of ten major lakes in the country forrevival and improvements. The restoration/revival programme,fully funded by the NLCP, was launched in April 2002, andimplemented by Bombay Municipal Corporation (BMC) nowcalled Brihanmumbai Municipal Corporation (BMC). Adjoining Attractions  Mahakali Caves Follow me on www.webbieguru.blogspot.com
  • 14. The Mahakali caves built about 2000 years ago has severalrock-cut figures of the Buddha and Buddhist legends. Thesecaves are situated in Udayagiri hills near the Kondivita village.  Kanheri cavesThe Kanheri Caves are located north of Borivli on the westernoutskirts of Mumbai, within the Sanjay Gandhi National Parksgreen forests.  Sanjay Gandhi National Park wildlife parkSanjay Gandhi National Park, earlier called Krishnagiri NationalPark covers an area of 104 sq. km and is the largest park in theworld, located within city limits. CONCLUSION  Powai lake having catchment area of 6.61 Sq. Kms & lake surface area of 2.10 Sq. Kms is improved within a period of 12 months. This is the 1st successful project executed in India using “Aeration and Bio- remediation Technique”.  The status of lake was transformed from Hypertrophic condition to Mesotrophic condition.  Use of the aeration and bioremediation technique was effective for improving the quality of lake water to the accepted standard for water bodies being used for fishing and recreational purposes. Follow me on www.webbieguru.blogspot.com
  • 15.  Though the installation cost of equipment, power and monitoring the water quality is high, the cost of maintenance is relatively low.Follow me on www.webbieguru.blogspot.comFollow me on www.webbieguru.blogspot.com