Chapter 3: Water Resources (Geography)

(a) Not suffering (b) Suffering (c) Suffering (d) Not suffering

(c) Multi-purpose projects lead to large-scale displacements and loss of livelihood.

1. Multiplying urban centres with large and dense populations and urban lifestyles have added to water and energy requirements and aggravated the problem of water scarcity (over-exploitation of groundwater).
2. Regulating and damming of rivers affects their natural flow, causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, and harms aquatic life.
3. Today in western Rajasthan, the practice of rooftop rainwater harvesting is on the decline as plenty of water is available due to the perennial Indira Gandhi Canal.

See the corrected statements above.

Fresh water is continually renewed and recharged by the hydrological cycle. Water evaporates from oceans, lakes and land, forms clouds, falls as rain or snow (precipitation), and flows back as rivers and groundwater. Because this cycle never stops, water is a renewable resource.

It is constantly recycled through the hydrological cycle (evaporation, condensation, precipitation and run-off).

Water scarcity is the shortage of water, i.e. when the demand for water is more than the available supply.

Causes:

• Over-exploitation and excessive use due to a large and growing population;
• unequal access to water among different social groups;
• intensive irrigation for dry-season agriculture and expanding industries;
• urbanisation and urban lifestyles;
• pollution of water by domestic and industrial wastes, chemicals, pesticides and fertilisers, which makes it unfit for use.

A shortage of water when demand exceeds supply, caused by over-use by a growing population, irrigation, industry, urbanisation, unequal access and pollution.

They provide irrigation, power, water supply and flood control, but disturb rivers and aquatic life, displace people and may cause floods and soil salinity.

• In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all houses traditionally had underground tanks or tankas for storing drinking water.
• The tanks could be as large as a big room; one household in Phalodi had a tank 6.1 metres deep, 4.27 metres long and 2.44 metres wide.
• The tankas were part of a well-developed rooftop rainwater harvesting system, built inside the main house or the courtyard. They were connected to the sloping roofs of the houses through a pipe. Rain falling on the rooftops travelled down the pipe and was stored in the tanks.
• The first spell of rain was usually not collected, as it would clean the roofs and pipes. Rainwater from the later showers was then collected.
• Rainwater, or palar pani, is considered the purest form of natural water. It is used as drinking water until the next rainfall, even when all other sources dry up in summer.
• Many houses built underground rooms next to the tanka to beat the summer heat, since the water kept the room cool.
• In the dry areas, agricultural fields were also turned into rain-fed storage structures called khadins (Jaisalmer) and johads (other parts), which kept the soil moist for growing crops.

Houses had underground tanks (tankas) linked by pipes to their sloping roofs; after the first rain cleaned the roof, rainwater (palar pani) was stored for drinking, and fields were turned into khadins and johads.

• Rooftop rainwater harvesting is now common in cities. In Karnataka, the village of Gendathur has rooftop systems in nearly 200 households, which collect about 1,00,000 litres of water annually; this makes the village rich in rainwater.
• Tamil Nadu is the first state in India to have made rooftop rainwater harvesting compulsory for all houses across the state, with legal provisions to punish defaulters.
• In Meghalaya, the 200-year-old system of bamboo drip irrigation is still used: water from streams and springs is diverted through bamboo pipes to the plantations, where it drips onto the roots of plants.
• In western Rajasthan, the traditional tankas are being revived and recharge pits and check dams are built to raise the groundwater level.
• In Shillong, which faces an acute water shortage even though Cherrapunji and Mawsynram nearby get the highest rainfall in the world, nearly every household has a rooftop harvesting structure, which meets about 15–25 per cent of its water needs. Excess water from such systems is led into wells and pits to recharge groundwater.

Rooftop harvesting is spreading (e.g. Gendathur village in Karnataka; compulsory in Tamil Nadu), bamboo drip irrigation continues in Meghalaya, and recharge pits and check dams are used to refill groundwater.