ICSE CLASS 10 GEOGRAPHY // WATER RESOURCES // IMPORTANT QUESTION ANSWERS

 

ICSE CLASS 10 GEOGRAPHY // WATER RESOURCES //

 IMPORTANT QUESTION ANSWERS

 

What are the sources of water?

Answer: Fresh water is obtained from rain water, surface water and ground water. The main sources of water are rain and snow which form a part of the hydrological cycle.

Surface Water: India is blessed with a number of rivers, lakes, streams and ponds.

Ground Water: Aquifers are underground reserves of fresh water.

Give three reasons why irrigation is necessary in India?

Answer:

Three reasons of necessity of Irrigation: (I) Due to irrigation high yielding crops are grown even when there is low and uncertain rainfall.

 (ii) Irrigation enhances agricultural productivity and it also promotes stability in production of crops. 

(iii) The nature of certain crops (Rice, Sugarcane, Jute) is such that they require large quantities of water for their growth. Irrigation fulfills the water requirement of such crops

What are the different types of irrigation practiced in India?

Answer: Irrigation can be carried out by two different methods:

q Traditional Methods

1.    Wells

2.    Tank

3.    Inundation

 

q Modern Methods

1.    Canal

2.    Sprinkler

 What do you understand by tank irrigation?

Answer: A tank irrigation as an irrigation storage system and is created by building a small bund of earth or stones across a stream.

State two disadvantages of tank irrigation.

q Answer: Drying up of tanks during dry season which is the most required season of irrigation.

q Silting of tank bed.

What is the main difference between inundation canals and perennial canals?

Answer:

Give two reasons why well irrigation is more important in North Indian than southern India.

Answer: Since the south India have ocean or sea around and have fruitful soil. Whereas the north India has no ocean and on seas around their is mountain and soil isn't ripe and that is the reason.it should be flood and when water misfortune the limit of fruitfulness than we need to inundate soil.

Give two reasons why tube well is more important than ordinary well for irrigation.

Answer: 1. Speed of the extraction of the water by tube well is more than ordinary well.

 2. Less amount of labor is used which increases the income of the farmer.

Name two states in which tank irrigation is more important than in any other state in India.

Answer: Tank irrigation is found more popularly in rocky plateau areas of the country especially in the plateau region of Southern India. The states in which they are practiced mainly are Andhra Pradesh and Tamil Nadu.

Name two states where tube wells are used extensively.

Answer: Tube wells are extensively used in Uttar Pradesh and Haryana. It is an important source of irrigation as it irrigates large areas of land in comparatively less time and it can irrigate the fields throughout the year.

What factors allow the construction of tube wells in the states named?

Answer: Factors favorable for construction of tube well:

Ø Availability of sufficient amount of groundwater should be present.

Ø Water level should be nearly 25 meters if not cost of pumping out water becomes uneconomic.

Ø There should be regular supply of electricity.

Ø Better to be constructed in the areas where irrigation is required.

Explain two disadvantages of well irrigation.

Answer: Two disadvantages of well irrigation are-

Ø Wells depend on underground water resources whose distribution varies from region to region.

Ø The traditional wells dry up due to over withdrawal of the ground water and lowering of the water table.

What is the need for conservation of water? discuss.

Answer: Water conservation is important because it keeps water clean and pure and conserves the environment. It is also important because the supply of water is not endless. About 2 percent of Earth’s freshwater is locked in glaciers and ice caps, while 97 percent is salt water. Therefore, only 1 percent of water on Earth is available for drinking.

Water conservation involves refraining from water pollution. It is important because, currently, only about 10 percent of Earth’s wastewater is disposed of appropriately.

What is rainwater harvesting?

Answer: Rainwater harvesting is the simple process or technology used to conserve rainwater by collecting, storing, conveying and purifying of rainwater that runs off from rooftops, parks, roads, open grounds, etc. for later use.

Write four benefits of rainwater harvesting.

Answer: rainwater harvesting has a number of benefits at both individual level and city wide level. Followings are the benefits of rainwater harvesting

Ø It recharges into the ground water which would be a positive impact on the groundwater.

Ø Recharging the groundwater would stop decline the level and quality of underground water

Ø Being a fresh water, it is used for different purposes.

Ø Urban flooding can be controlled if the city harvest rainwater from their rooftop for future use.

Ø It would bring down consumer utility bills

Define Johad.

Answer: Johads are small earthen check dams that capture and conserve rainwater, improving percolation and groundwater recharge.

Describe two methods to harvest rain water?

Answer: 1. Rooftop rainwater harvesting. In this system, the rainwater from the rooftop is collected in a storage tank, through pipes.

2. Another method, a big pit is dug near house for collecting rainwater. This pit is filled with different layers of bricks, coarse gravels and sand or granite pieces.

Irrigation is the key success of India’s agriculture” justify this statement.

Answer: Approximately 80 per cent of India's total annual rainfall occurs over four months, i.e. between mid-June and mid-October. It is therefore necessary to provide irrigation during the rest of the eight months for the development of crops, etc.

(2) Monsoons are unpredictable. So irrigation, as a result of uncertain rainfall, is important to protect crops from drought.

(3) In all parts of the world, it does not rain the same way. In less rainy areas, irrigation is therefore important for agriculture.

(4) The soils in some regions are sandy and loamy, and thus porous, for which a significant portion of the rainwater is very rapidly sinking. So, sandy and loamy soils, like alluvial soil and black soil, cannot hold water. That is why irrigation is essential in areas with sandy and loamy soils for agriculture.

(5) The rain-water flows down over the hillside slopes very rapidly. Irrigation is therefore required in such areas to grow crops.

Define hydrological cycle.

Answer: The water cycle or hydrological cycle is a continuous cycle where water evaporates, travels into the air and becomes part of a cloud, falls down to earth as precipitation, and then evaporates again. This repeats again and again in a never-ending cycle.

Write Two merits and demerits of canal irrigation

Answer: Merits:

 

·       These are effective means of irrigation.

·       They generate income to government.

·       They cover large area for irrigation.

·       Canals are effective means to sustain drought.

·       Carry sediment which enrich the fertility of soil.

Demerits:

 

Ø Cause problem of waterlogging and alkalinity in the peripheral areas.

Ø Irrigation through water often causes wastage of water.

Ø Causes disputes regarding sharing of water.

Ø Danger of spreading water borne disease in peripheral areas.

Two merits and demerits of wells irrigation

Answer: Merits:

Simplest and cheapest source of irrigation.

Well can be dug at any convenient place.

Several chemicals such as nitrate, chloride, sulphate, etc. are generally found mixed in well water. They add to the fertility of soil when they reach the agricultural field along with well water.

Demerits:

Only a limited area can be irrigated normally up to 1 to 8 hectares of land.

If once dried up, it may be considered useless.

Not possible in areas with brackish groundwater.