Ans) Three-fourths of the earth’s surface is covered with water, but only a small proportion of it accounts for freshwater that can be put to use. This freshwater is mainly obtained from surface runoff and groundwater that is continually being renewed and recharged through the hydrological cycle. This surface water disappears through evaporation, and after condensation comes back to the earth as rainfall. This ensures that water is a renewable resource.

Ans)

Surface Water Resources	Underground Water Resources
Rainwater that flows or stagnates on the surface is known as surface water	Rainwater, which is absorbed in the lower layers of the surface, is called the underground water resources.
Surface water occurs in rivers, ponds, lakes and puddles.	Underground water can be obtained through wells and pumping devices.
Its use is wide, easy and inexpensive.	Its use is difficult and expensive, and obtained in less quantity.
Industrialisation is made possible in the regions where surface water is in abundance.	Underground water is used for agriculture, domestic works and  industries. It can not be used for energy production.

Ans) Meaning of dams –  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. Most dams have a section called a spillway or weir over which or through it is intended that water will flow either intermittently or continuously.

Classification – Dams are classified as per their structure, intended purpose or height. Based on structure and the material used, dams are classified as timber dams, embankment dams or masonry dams, with several subtypes. According to height, dams can be categorised as large dams and major dams or alternatively as low dams, medium height dams and high dams.

Ans) Sardar Sarovar Dam has been built over the Narmada River in Gujarat. This is one of the largest water resource projects of India covering four states-Maharashtra, Madhya Pradesh, Gujarat and Rajasthan. The Sardar Sarovar Project would meet the requirement of water in drought-prone and desert areas of Gujarat (9,490 villages and 173 towns) and Rajasthan (124 villages).

Ans) The Krishna-Godavari dispute has started with the objections raised by the Karnataka and Andhra Pradesh governments. It is regarding the diversion of more water at Koyna by the Maharashtra government for a multipurpose project. This would reduce down stream flow in their states with adverse consequences for agriculture and industry.

Ans) In India, the rainfall distribution is unequal. The availability of underground water is depends on rainfall. We have to depend on the rivers and underground water for drinking water. However, the underground water of all places is not fit for drinking. Even in high rainfall areas also, rain water flows soon or dried up through evaporation. Hence, in spite of heavy rainfall, India is thirsty for land water.

Ans) It is a good example of water management through scientific methods on a large scale. It is the highest gravitational dam of the world. 7,80,000 hectare metres of water can be collected in the lake formed behind the dam. Canals of 1100 km. are drained from this dam. There are 3,400 km. long water channels of these canals, through which 14 lakh hectare land is irrigated. A hydel power plant is constructed at a place called Nangal, where there is production of power. The states that are benefited by this project are Himachal Pradesh, Punjab, Haryana, Rajasthan and Delhi.

Ans) Chambal Project – The Chambal project is a joint venture of Madhya Pradesh and Rajasthan states. It is used for irrigation in both districts. Its major motive is to conserve soil in the Chambal riverbed. The entire project has been completed by the construction of three dams. The Gandhi Sagar dam is in Madhya Pradesh and Kota barrage and Rana Pratap Sagar dam in Rajasthan. The irrigation capacity of this project is 5 lakh hectare.

Ans) Advantages of Multipurpose River Projects:-

1. Electricity production
2. Domestic and industrial uses
3. Water supply
4. Flood control
5. Entertainment
6. Inland navigation
7. Fish breeding

Disadvantages of Multipurpose River Projects:-

1. Damming of rivers affects their natural flow.
2. Excessive sedimentation at the bottom of the reservoir resulting in floods.
3. The multipurpose projects induced earthquakes, caused water-borne diseases and pests and pollution resulting from excessive use of water.
4. Large dams have also been the cause of many new environmental movements like the ‘Narmada Bachao Andolan’ and the “Tehri Dam Andolan’ etc.

Ans) Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. It is interesting because Cherrapunji and Mawsynram, situated at a distance of 55 km from Shillong, receive the highest rainfall in the world, yet the state capital Shillong faces an acute shortage of water. Nearly every household in the city has a rooftop rainwater harvesting structure. Nearly 15-25 per cent of the total water requirement of the household comes from rooftop water harvesting.

Ans) Government of India has accorded highest priority to improve the quality of life and enhance ease of living of people especially those living in rural areas by announcing the 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 litre per capita per day regularly on long-term basis by ensuring functionality of the tap water connections.