restoration methods of lakes and tanks

7/29/2019 Restoration methods of lakes and tanks

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CONTENTS

1. Introduction.2. Formation of Lakes3. Significance of Lakes4. Lakes in Bangalore5. Reasons for extinction of Lakes and Tanks6. Effects of extinction of Lakes and Tanks7. Restoring Measures

a. Short Term Measuresb. Long Term Measures

8. Conclusion


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INTRODUCTION

A lake is a body of relatively still water of considerable size, localized in a depression

that is surrounded by land apart from a river, stream, or other form of moving water that

serves to feed or drain the lake. Many lakes are artificial constructed for industrial or

agricultural use, for hydro-electric power generation or domestic water supply, or for

aesthetic or recreational purposes. Lakes provide humankind with many services like

aesthetic enjoyment, recreation, fish, transportation, water for irrigation, drinking and

dilution of pollutants.

Lake in Bariloche, Argentina

The essential condition for the existence of a lake is that water should flow into the

depression at least as fast as it is withdrawn from it by factors like evaporation,

underground seepage and to an outfit if any.

Lakes may be found at very high altitudes in mountains or plateaus. They may be at

sea level or below sea level. They can be very big like Caspian Sea or small like a pond.
http://en.wikipedia.org/wiki/File:Bariloche-_Argentina2.jpg


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They can be deep or shallow, drying up during a part of the year. But the most distinctive

feature is whether it is a fresh or saline lake.

FORMATION OF LAKES

The formation of lake basins may be due to various reasons. The movement of the

earth's crust may form lake basins. They may be caused by volcanic action. Very often

they are the legacies of glaciers. Lakes may represent the work of a river. They may be

the result of marine action. They may owe their origin to sink holes or a chemical solution

of limestone. They can also develop as a result of continuous wind action. Also cause

deformation of lakes but generally they are short lived.

Hydrologic Cycle

Natural lakes are generally found in mountainous areas, rift zones, and areas with

ongoing glaciations. Other lakes are found in endothecia basins or along the courses of


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mature rivers.All lakes are temporary over geologic time scales, as they will slowly fill inwith sediments or spill out of the basin containing them.

SIGNIFICANCE OF LAKES

97.5% of the Earths water exists in the seas, and nearly all of the remaining freshwater is locked up in the Antarctic or Arctic ice caps or as groundwater. Therefore,

we can freely access only the water in lakes (0.007%) and in rivers (0.002%).

Large lakes and reservoirs are used as a source of drinking water. Lakes are used by humans for many commercial purposes, including fishing,

transportation, irrigation, industrial water supplies, and receiving waters forwastewater effluents.

Beside from their importance for human use, lakes have intrinsic ecological andenvironmental values.

Lakes also help in moderating temperature and influence the climate of thesurrounding land.

They store water, thereby helping to regulate stream flow; recharge ground wateraquifers; and moderate droughts.

They provide habitat to aquatic and semi aquatic plants and animals, which in turnprovide food for many terrestrial animals; and they add to the diversity of the

landscape.

Most of the lakes in India are renowned for their religious importance like Pushkarlakes in Rajasthan, Gurudongmar Lake in Sikkim, Nako Lake, Bhirgu Lake, Dal Lake

and others.


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Fishing in Lakes

The following data provided by The Japanese Prefectures Association

on the Promotion of Environmentally Sound Management of Lakes


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LAKES IN BANGALORE

Most lakes in the Bangalore region were constructed in the Sixteenth century by

damming the natural valley systems by constructing bunds.Most of the lakes and tankswere manmade for purposes of drinking water, irrigation and fishing needs and they have

also favourably influenced microclimate of the city.

In the 1960s the number of tanks and lakes was 280 and less than 80 in 1993. Most ofthe lakes have vanished due to encroachment and construction activity for urban

infrastructure expansion. Out of 280 lakes, 7 cannot be traced, 7 are reduced to small

pools of water, 18 have been unauthorised encroached by slums and private parties, 14

have dried up and are leased out by the Government. 28 lakes have been used by the

Bangalore Development Authority to distribute sites and build extensions for residential

areas. The remaining lakes are in fairly advanced state of deterioration.

PRESENT STATUS OF LAKES AND TANKS

Name of the Lake/Tank

In Bangalore:

Institution/Building

Nagasettyhalli Lake The Space department

Kadugondanahalli Lake Ambedkar Medical College

Kodihalli Lake The Space department

Challaghatta Lake The KSTDC for a golf course

Dharmambudhi Tank Bangalore City Bus stand

Millers Tank Residential layout

Sampangi Tank Kanteerava stadium

Shuley Tank Football Stadium

Koramangala Tank Sports complex

Domlur Lake BDA layout


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Kurubarahalli Lake Residential layout

Kamakshipalya Lake Sports ground

Dasarahalli Tank Dr. B.R Ambedkar Stadium

Sinivaigalu Lake Residential layout

Karanji Tank Gandhi Bazaar area

Siddikatte Lake KR Market

Once upon a time, there was a lake here.....

Bangalore city Bus Stand, once DharmambudhiTank

The KGA Golf Course once the Challaghatta Tank


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The Koramangala Tank is today a Sports Complex

A Sports stadium today was the Sampangi Tank earlier

REASONS FOR THE EXTINCTION OF LAKES

AND TANKS

Now-a-days, as grounds are being leveled due to urbanization, water isflowing as "run-off" instead of seeping into soil. This reduces the ground

water table, in turn resulting in drying up of tanks.

Removal of vegetation in the catchment area "Eutrophication" due to industrial effluents and agricultural wastes "Siltation" of tank bed Drying of tanks for construction purpose Encroachment of dried tank lands Deforestation resulting in loosening of soil Dumping all garbage and sewage into the tanks Growing of weeds in the tank making it useless.


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EUTROPHICATION

The process by which a body of water acquires a high concentration of nutrients,

especially phosphates and nitrates. These typically promote excessive growth of algae.

As the algae die and decompose, high levels of organic matter and the decomposing

organisms deplete the water of available oxygen, causing the death of other organisms,

such as fish. Eutrophication is a natural, slow-aging process for a water body, but human

activity greatly speeds up the process.


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SILTATION

A process by which water becomes dirty as a result of deposition of finely divided soil

and rock particles upon the bottom of lake bed.Siltation can affect navigation channels,or irrigation channels.

EFFECTS OF EXTINCTION OF TANKS AND LAKES

It has lead to flooding of cities during heavy rains Scarcity for drinking water Damage to aquatic life. Due to developmental activities in the catchment area, the drainage connectivity

between important wetlands has been lost.

This has resulted in a loss and shrinkage of wetlands leading to the destruction andloss of habitat for flora, fauna and migratory birds.


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There has also been depletion in the ground water table. The health hazards due to pollution of lakes result in enrichment of Bacteria, Viruses,

Protozoa, Spirochetes and Helmints. This in turn results in water borne diseases like

diarrhea, dysentery, typhoid, paratyphoid, cholera, poliomyelitis, viral hepatitis,

giardiasis and worm infestations.

Damage to aquatic life due to extinction of Lakes

RESTORING MEASURES

A)SHORT TERM MEASURES Cleaning the drains that bring storm water to the lake. Providing additional silt traps along the upper reaches of the drains. Providing bar screens at the mouth of the lake, for the drains. Immediate deweeding of the lake.


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Rearing special kind of fish which feed on dirt in the tank. E.g. Gambusia fishfeed on mosquito larvae.

Provision of dustbins around the lake. Posting of security staff around the lake to prevent dumping of garbage. Creating public awareness to keep the lake clean with the help of sign boards. Formation of a lake protection committee involving local people.

Local people cleaning the Lake

B)LONG TERM MEASURES Removal of sediments & silt by dredging the lake during summer period. In order to avoid the flow of sullage into the lake, sewers are laid around the lake

for diverting the flow of sullage into the treatment plant.

Formation of a standing committee comprising officers from the city corporation,water supply and sanitation board, pollution control board, state tourism

development corporation, fishery department and department of ecology &


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environment for follow-up action. Noted environmentalists may also be included

in the committee.

Fencing of the lake bed to prevent it from being encroached & misused. Legislative measures to ban the production of detergents containing poly

phosphates are required in the interest of environmental protection.

Educating the public on the need to maintain a clean environment is also veryimportant. Awareness about polluted water affecting our health should spread. It

will be very useful if this is done by the public rather than the government. Only

such awareness can save tanks in rural areas.

Formulation of a Lake Authority at State level and Central Lakes Authority atNational Level.

To identify major lake systems and highly contaminated lakes. Action plan todivert the sewers discharging into lakes suitably. Laying new sewers to convey

the sewage discharged by storm water drains away from lakes.

Regular monitoring of the lake water quality by the Pollution Control Board.

Removal of Aquatic plants


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Desiltation of Lake bed. Interception and diversion of

Sewage entering Lakes

Monitoring water quality public awareness programmes

CONCLUSION

Restoration & Conservation of Lakes & tanks will be an asset to the society andalso to the eco system.

Domestic, Commercial & Industrial water needs can be fulfilled. It also leads to the development of lake areas into tourism spots, bird sanctuaries,

parks, home of wild life etc; which in turn contributes to economy of a country.


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restoration methods of lakes and tanks

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