1. Large dams can ensure storage of adequate water which can be used for irrigation. Canal systems leading from dams can transfers water to great distances eg. Indira Gandhi Canal has brought greenary to large areas of Rajasthan.
2. Stored water can be used for generating electricity.
3. Dams also control floods.
What are the reasons for opposition to construction oflarge dams like Tehri Dam on river Ganga?
Large dams Construction causes three problems:
Social Problems: Large numberof peasents and tribals are displaced without adequate compensation or rehabilitation.
Economic Problem: Huge amounts of public money is used in constructing dams without yhe generation of proportionate benefits.
Encironmental Problems: Dam construction leads to deforestation and loss of biological diversity.
What is Narmada Bacho Andolon?
It is a protest against raising ythe height of Sardar Sarover dam on river Narmada.
What is water shed management?
- Watershed management amphasises soil and water conservation to increase biomass production.
- Watershed management increases income of watershed community
- It also prevents droughts and floods.
- It increase the life of the dewnstream dam and reserviors.
What are the ancient or traditional systems of water harvesting?
- Digging small pits and lakes.
- put in place simple watershed systems.
- Building small earthen dams
- Construting dykes
- sand and limestone reservoir
- Setting up rooftop water collecting units
Name some of the ancient or traditional water harvesting structure/systems still in use.
- Khadins and Nadis in Rajasthan
- tals in Maharashtra
- Bundhis in M.P.and U.P.
- ahars in Bihar
- Kulhs in H.P.
- Eris in T.N.
- Surangams in Kerala
- Kattas in Karnataka
Describe the structure of water harvesting structure in largely terrain?
- In a largely level terrain water harvestinh structures are mainly crescent shaped earthen embankments or low, straight concrete and rubble checked dams built across seasonal flooded gullies.
- Monsoon rains fill ponds behind the structures.
- Only large structures holds water throughout the year while most dry up after monsoon
- The main purpose of water harvesting structures is not to hold the surface water but to recharge the ground water.
Write significance of water stored in ground.
- It does not evaporate, but recharges wells and provides moisture for vegetation over a wide area.
- It does not provide breeding grounds for mosquitoes like stagnant water bodies.
- Ground water is not contaminated by human and animal waste.
Why do we need to use coal and petroleum (Fossil Fuels) judiciously?
- Coal and petroleum are non- renewable resources. These were formed from degradation of biomass millions of years ago and will be exhausted in future.
- When coal and petroleum are burnt, they release SO2, CO2 oxides of N2. When combustion takes place in insufficient oxygen, CO is formed along with N2O and SO2 which are all poisonous high concentration and pollute our environment.
- CO2 formed by complete combustion of fossil fuel is a green house gas and causes global warming
What are two advantages of giving people control over resources?
1. Controls mismanagement of resources
2. Reduces over- exploitation of these resources.
How is Ganga river getting polluted? Which project has bean laiddown by Government to clean Ganga?
Causes of Pollution
- Largely untreated garbage and sewage is dumped into Ganga every day from state like U.P. Bihar andWest Bengal.
- Huamn activities like bathing, washing ofclothes, immersion of ashes or unburnt corpses pollute water.
- Chemical effluents from industries also pollute Ganga and these toxic chemicals kill fish and other aquatic organisms in the river
A multicroreproject-- Ganga action plan was imlemented in 1985 to clean Ganga water
What changes can you make in your habits to become more environment friendly?
- Save water by repairing the leaked taps.
- Switch off unnecessary lights and fans
- Don't waste food
3.Reuse the thing again and again eg. using jam bottles to store some other material
4. Growing plants at your home and in surroundings
5.Stop using products like fur. Ivory from wild life.
Draw diagram of traditional water harvesting system --Khadin System
Refer to Fig16.3 Page No. 276 of NCERT Book