Water resources class 10 Geography notes is comprehensively discussed which would cover various topics of chapter 3 water resources of class 10 Geography ncert.It encompasses topic like sources of freshwater ,water scarcity,causes of water scarcity,dams and multipurpose projects and rainwater harvesting.
Water
Three-fourth of the earth’s surface is covered with water, but only a small proportion of it accounts for freshwater which is less than
Sources of Freshwater
• Surface run off
ground water
• Precipitation
All water moves within the hydrological cycle ensuring that water is a renewable resource.
WATER SCARCITY AND THE NEED FOR WATER CONSERVATION AND MANAGEMENT
Given the abundance and renewability of water,we suffer from water scarcity. we immediately associate it with regions having low rainfall or those that are drought prone.
Causes of Water Scarcity
•The availability of water resources varies over space and time, mainly due to the variations in seasonal and annual precipitation
•Over-exploitation
•Excessive use
• unequal access to water among different social groups
• Large and growing population
• Water intensive agriculture
• Industrialisation and urbanisation
Population and Water Scarcity
A large population requires more water not only for domestic use but also to produce more food. Hence, to facilitate higher food-grain production, water resources are being over-exploited to expand irrigated areas for dry-season agriculture. Irrigated agriculture is the largest consumer of water
Industrialisation and Water Scarcity
Industries, apart from being heavy users of water, also require power to run them. Much of this energy comes from hydroelectric power. Today, in India hydroelectric power contributes approximately 22 per cent of the total electricity produced.
Urbanisation and water scarcity
Multiplying urban centres with large and dense populations and urban lifestyles have not only added to water and energy requirements but have further aggravated the problem. They have their own groundwater pumping devices to meet their water needs.There has been a growing concern that even if there is ample water to meet the needs of the people, much of it may be polluted by domestic and industrial wastes, chemicals,pesticides and fertilisers used in agriculture, thus, making it hazardous for human use.
Jal Jeevan Mission (JJM)
The Goal of JJM is to enable every rural household get assured supply of potable piped water at a service level of 55 litres per capita per day regularly on long-term basis by ensuring functionality of the tap water connections.
Need to conserve water resources
• To safeguard ourselves from health hazards
• to ensure food security, continuation of our livelihoods and productive activities
• to prevent degradation of our natural ecosystems.
Over exploitation and mismanagement of water resources will impoverish this resource and cause ecological crisis that may have profound impact on our lives.
Forest and Wildlife Resources Class 10 Geography Notes
Dam
A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment.“Dam” refers to the reservoir rather than the structure.
Advantages of Dams( Multiplepurpose projects)
• impound rivers and rainwater that could be used later to irrigate agricultural fields.
• built not only for irrigation but also for electricity generation.
• Water supply for domestic and industrial uses• flood control
• Recreation
• inland navigation and fish breeding.
Hence, dams are now referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another.
Development and Multipurpose Projects
Multi-purpose projects, launched after independence with their integrated water resources management approach, were thoughtof as the vehicle that would lead the nation to development and progress, overcoming the handicap of its colonial past. Jawaharlal Nehru proudly proclaimed the dams as the ‘temples of Modern India’; the reason being that it would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy.
Negative Consequences of Multipurpose Projects and Dams
• Regulating and damming of rivers affect their natural flow causing poor sediment flow.
• excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers’ aquatic life.
• Dams also fragment rivers making it difficult for aquatic fauna to migrate, especially for spawning.
• The reservoirs that are created on the floodplains also submerge the existing vegetation and soil leading to its decomposition over a period of time
• cause of many new environmental movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan.
• Local people often had to give up their land, livelihood and their meagre access and control over resources for the greater good of the nation
Reason for opposition of Multiple purpose projects
• Triggered floods due to sedimentation in the reservoir
• Also caused extensive soil erosion.
• Induce earthquakes, caused water-borne diseases and pests and pollution resulting from excessive use of water
Rainwater Harvesting
Water harvesting is a system of collection and storage of rain water that runs off from roof tops, open grounds, et that is either stored or recharged into the groundwater. Water harvesting system was a viable alternative, both socio-economically and environmentally . People had in-depth knowledge of rainfall regimes and soil types and developed wide ranging techniques to harvest rainwater, groundwater, river water and flood water in keeping with the local ecological conditions and their water needs.
•In Hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture.
•‘Rooftop rainwater harvesting’ was commonly practised to store drinking water, particularly in Rajasthan.
• In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
• In arid and semi-arid regions, agricultural fields were converted into rain fed storage structures that allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan
• In Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water.
• Rainwater, or Palar pani, as commonly referred to in these parts, is considered the purest form of natural water.
Important Facts
• Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya
• Cherapunjee and Mawsynram situated at a distance of 55 km. from Shillong receive the highest rainfall in the world, yet the state capital Shillong faces acute shortage of water.
• Tamil Nadu is the first state in India which has made rooftop rainwater harvesting structure compulsory to all the houses across the state.