UNIT 2 EVS A.( Mechanical Engineering)pptx

mechanical engineering unit 2 ppt EVS

1. Unit- II Natural Resources

2. What is a Resource? Any stock or reserve that can be drawn from nature is a natural resource. Or Natural resource is “ any commodity or a source of supply held in reserve in biosphere, which is, at present, or can be in future, important for the survival of living organisms in general, and humans in particular .”

3. Types of Natural Resources Inexhaustible Exhaustible Renewable Non renewable Solar energy i ) Water i ) Fossil fuels Wind energy ii) Wildlife ii) Minerals Tidal energy iii) Soil fertility iii) Nuclear energy Geothermal energy iv) Natural vegetation Hydropower OTEC

4. Forest Resources

5. Indian Forest Statistics (2019) Total geographic area 32,87,469 sq km Total Forest cover 712,249 sq km (21.67% of total area) Forest classes: Sr. No. Category Percentage Very dense Forest 3.02% Moderately dense 9. 39% Open Forest 9.26% 21.67% Scrub 1.41 Non- forest 76.92 100%

6. Uses of Forests Commercial uses Environmental uses Timber Regulates water cycle Pulpwood Produces oxygen Fruits, spices Absorbs pollution Fodder Act as sink of Carbon Rubber, gum Habitat for wildlife Fibers Conservation of soil Drugs and Medicines Minerals

7. Deforestation Major causes of deforestation Shifting cultivation Fuel requirement Raw material for industrial use Development projects Growing food needs Overgrazing Forest fires

8. Major activities in Forests Timber Extraction Mining Dams

9. Consequences of deforestation Destruction of habitat of wildlife. Loss of biodiversity. Hydrological cycle gets affected. Problem of soil erosion and loss of soil fertility increase. Global warming is enhanced.

10. Forest Management Joint Forest Management (JFM) is partnership involving both the forest departments and local communities in natural forest management. The concept was introduced by Government of India through the National Forest Policy of 1988. Sustainable forest management , also known as sustainable forestry, is the practice of regulating forest resources to meet the needs of society and industry while preserving the forest's health. Therefore, sustainable forest management is always looking to strike a balance between the demand for the forest's natural resources and the vitality of the forest.

11. Agro-forestry: A sustainable system of managing a piece of land through combined production of agricultural crops and forest crops/ animals, either simultaneously or sequentially to ensure the most efficient land use under a management system in accordance with socio-cultural practices of local people. Social Forestry: It is the plantation in non-forest area for benefit of the society.

12. Case study Sardar Sarovar Dam Dam is situated on river Narmada Spread over three states of Gujarat, Maharashtra and Madhya Pradesh. Aim : Providing irrigation water, drinking water and electricity Total of 573 villages submerged by Dam 1,44,731 ha of land is submerged by land out of which 56,547 ha is forest land. Loss of various wildlife species like panthers, wolves, bears, jackals etc

13. Water Resources

14. Water Availability Global Water Fresh water Salt water 2.6% 97.4% Ice caps and glaciers(1.984%) Oceans and salt lakes Ground water(0.592%) Lakes(0.007%) Soil moisture(0.005%) Biota(0.0001%) Rivers(0.0001%) Atmospheric moisture(0.001%)

15. Sources of Freshwater Groundwater Surface water

16. Groundwater Aquifer: A layer of sediment or rock that is highly permeable and contains water is called an aquifer Aquifer may be of two types: Unconfined aquifer Confined aquifer

17. Unconfined aquifers which are overlaid by permeable earth materials and they are recharged by water seeping down from above in the form of rainfall and snowmelt. Confined aquifers which are sandwiched between two impermeable layers of rock or sediments and are recharged only in those areas where the aquifer intersects the land surface.

18. Effects of excess usage of groundwater Subsidence: When groundwater withdrawal is more than its recharge rate, the sediments in the aquifer gets compacted a phenomenon known as ground subsidence. Lowering of water table Water logging Water pollution.

19. Floods Causes of flood Deforestation Overgrazing Mining Rapid industrialization Global warming Storms and cyclones Cloud bursts

20. Consequences of Floods Loss of livestock and human lives. Migration from flood effected areas. Loss of homes ,destruction of crops, agricultural land. Isolation of flooded area from rest of rest of world. Failure of sewer systems, electricity supply and transportation in urban areas. Possibility of epidemics. Soil erosion. Increase in incidence of land slides

21. Control Measures of Flood Construction of dams, reservoirs. Embankments of rivers. Proper drainage system. Tree plantations. Soil erosion preventive techniques .

22. Drought When annual rainfall is below normal and less than evaporation, drought conditions are created. Types of drought: Metrological drought: significant decrease from normal precipitation. Agricultural drought: When soil moisture and rainfall is inadequate to support crops. Hydrological drought: Depletion of surface water and ground water sources to significant level.

23. Causes of drought Anthropogenic causes: Overgrazing, deforestation, mining, soil erosion, exploitation of ground/surface water etc Natural causes: Change in weather

24. Impacts Economic Loss of dairy/fishery/other livestock. Loss of livelihood/employment opportunities. Increased prices of food/fodder. Loss of hydroelectric power generation. b)Environmental Increased desertification Damage to biodiversity Depletion in ground water level. Soil erosion by wind

25. Social Food shortage Increased conflicts over distribution of water resources. Increased poverty.

26. Drought Management Water Conservation Vegetation cover Water storage Watershed Management Rain water Harvesting Drought tolerant crops

27. Conflicts over water Indus Water Treaty The kaveri water Dispute The Satluj - Yamuna Link canal dispute

28. Water Management Some traditional water management systems In south India a neerkatti manages traditional tanks very efficiently based on his/her knowledge. In Maharashtra the water managers are called havaldars or jaghyas who manage and resolve conflicts from main canal to distributory canals. In ladakh the water managers is known a s churpun who has got complete charge with full powers over allocation of available water.

29. Dams Benefits Losses Flood control Submergence of villages and fertile land Irrigation water supply Resettlement issues Hydro electricity Deforestation Drinking water supply Causes of flood For fisheries Causes damage to flora and fauna of that river Employments Reservoir induced seismicity