Water Resources Test - 2

In Gujarat, the Sabarmati basin farmers were agitated and almost caused a riot over the higher priority given to water supply in urban areas, particularly during droughts.

Mettur Dam, which forms Stanley Reservoir, is constructed across the Kaveri River in Tamil Nadu. It was constructed in 1934 and took 9 years to complete. Maximum height and width of the Dam are 214 and 171 feet respectively. Maximum storage height is 120 feet. Mettur Dam receives the water from both Kabini Dam and Krishna Raja Sagara Dam located in Karnataka. There are 2 hydroelectric power stations in Mettur Dam, the first constructed during British rule and the second during the Indian Republic. There is a park at the base of the dam called Ellis Park maintained by the Tamil Nadu Public Works Department.

Rooftop rainwater harvesting is done in Rajasthan. In the flood plains of Bengal, people developed inundation channels to irrigate their fields. Inundation channels are channels meant to carry overflow of water from rivers and other water bodies to fields for irrigation. Such channels have been a traditional means of water harvesting in India.

The Chambal River is a tributary of the Yamuna River in central India, and thus forms part of the greater Gangetic drainage system. The river flows north-northeast through Madhya Pradesh, running for a time through Rajasthan, then forming the boundary between Rajasthan and Madhya Pradesh before turning southeast to join the Yamuna in Uttar Pradesh state. The dams situated on the river Chamba are Gandhi Sagar Dam, Rana Pratap Sagar Dam, Kota Barrage and Jawahar Sagar Dam.

In Gendathur, a remote backward village in Mysore, Karnataka, villagers have installed in their households rooftop rainwater harvesting system to meet their water needs. Nearly 200 households have installed this system and the village has earned the rare distinction of being rich in rainwater harvesting.

Sedimentation affects the safety of dams and reduces energy production, storage, discharge capacity and flood attenuation capabilities. It increases loads on the dam and gates, damages mechanical equipment and creates a wide range of environmental impacts. The environmental impacts of sedimentation include the following: loss of important or sensitive aquatic habitat, decrease in fishery resources, loss of recreation attributes, loss of coral reef communities, human health concerns, changes in fish migration, increases in erosion, loss of wetlands, nutrient balance changes, circulation changes, increases in turbidity, loss of submerged vegetation, and coastline alteration.

Freshwater is mainly obtained from surface runoff and ground water that is continually being renewed and recharged through the hydrological cycle. Water can neither be added nor be subtracted from the earth. Its total volume remains constant. Its abundance only seems to vary because it is in constant motion, cycling through the oceans, the air, the land and back again, through the processes of evaporation, precipitation and runoff. This is referred to as the 'water cycle'. Hence, water is a renewable resource.

Water scarcity in most cases is caused by over exploitation, excessive use and unequal access to water among different social groups. Water scarcity does not occur due to the reason that India receives 4 percent of global precipitation, as it simply measures the rainfall in comparison to the total global rainfall.

Big dams have mostly been unsuccessful in controlling floods at the time of excessive rainfall. The release of water from dams during heavy rains aggravated the flood situation in Maharashtra and Gujarat in 2006. The floods have not only devastated life and property but also caused extensive soil erosion. Sedimentation also meant that the flood plains were deprived of silt, a natural fertiliser, further adding on to the problem of land degradation. Regulating and damming of rivers affects their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers' aquatic life.

All the statements given above are correct. Multipurpose projects and dams affect the natural flow of rivers, resulting in poor sediment flow and excessive sedimentation at the bottom of the reservoir, thereby triggering floods. Multipurpose projects and dams induced earthquakes cause water borne diseases and pests and pollution. Dams cause fragmentation of rivers and block the migration routes of aquatic fauna, especially for spawning.

Kuls are traditional channels found in precipitous mountain areas. These channels carry water from glaciers to villages in the Spiti valley of Himachal Pradesh. Where the terrain is muddy, the kul is lined with rocks to keep it from becoming clogged. In the Jammu region too, similar irrigation systems called kuhls are found. Kuls are not circular ponds, but they take the water to the ponds.

Rooftop rainwater harvesting is important in Rajasthan because: (i) It was commonly practised to store drinking water. (ii) The rainwater can be stored in the tankas till the next rainfall making it an extremely reliable source of drinking water when all other sources are dried up, particularly in the summers.
Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. Shillong, the capital of Meghalaya, is situated only at a distance of 55 km from Mawsynram, the place receiving highest rainfall in the world. Yet, it faces acute water shortage as it is located in the rainshadow area on the leeward side of Khasi hills. So, nearly every household has rainwater harvesting structure to tap whatever amount of rainfall is received by the area for use during dry periods.
Tamil Nadu is the first state in India which has made rooftop rainwater harvesting structure compulsory to all the houses across the state. There are legal provisions to punish the defaulters.

Bhakra-Nangal project water is on the Sutluj-Beas river basin. Bhakra Dam is a concrete gravity dam on the Sutlej River in Bilaspur, Himachal Pradesh in northern India. The dam forms the Gobind Sagar reservoir. The dam holds excess waters during the monsoon and provides a regulated release during the year. It also prevents damage due to monsoon floods. The Bhakra Canal fed by this dam provides irrigation to 10 million acres of (40,000 km²) fields in Punjab, Haryana, and Rajasthan. Water flows from Bhakra Dam downstream Nangal dam where it is controlled and released into Nangal Hydel Channel that later becomes Bhakra Main Line after Ganguwal and Kotla power plants. The Bhakra main line is a canal that mostly supplies irrigation water to the state of Haryana.

In Meghalaya, a 200-year-old system of tapping stream and spring water by using bamboo pipes is prevalent. About 18-20 litres of water enters the bamboo pipe system, gets transported over hundreds of metres, and finally reduces to 20-80 drops per minute at the site of the plant.

Narmada Bachao Andolan (NBA) is an Indian social movement spearheaded by native tribals, farmers, environmentalists and human rights activists against a number of large dam projects across river Narmada, which flows through the states of Gujarat, Madhya Pradesh and Maharashtra. Sardar Sarovar Dam in Gujarat is one of the biggest dams on the river and was one of the first focal points of the movement. It is part of the Narmada Dam Project, whose main aim is to provide irrigation and electricity to people of the above states.