Forests are home to a variety of plants and animals. Several trees, shrubs, mosses, and mushrooms, birds and mammals, spiders, frogs, and snakes grow and live in forests. Human beings, too, depend on forests for a variety of things. Felling of trees and clearing of forests may have undesirable effects on all life forms on Earth.
About one-third of the world’s land surface is covered with forests. Forests are different from one another depending upon where they are located. Climate, topography (physical features) and soil type are some of the main factors that determine the type of trees and animals that grow and thrive in a forest. The current forest cover of the world is shown below.
According to the height of plants and trees, forests can be divided into three layers canopy, crown, and understorey. The uppermost layer of branches which serves as a dense roof of trees over the ground in a forest is called canopy. The layer where trees branch off from the tree trunk is called crown. The shaded layer of the forest where low light is available is called understorey. India has a diverse range of forests and their uses are equally diverse.
India is still not in the ‘water stressed’ category but the day is not far when we will be facing a water crisis. We need to think of various ways to strictly avoid wastage. Since only a small percentage of water on our planet is usable, it is very important that we use water carefully. Conservation of water can be done by building dams, avoiding wastage of water at homes, both indoors and outdoors, harvesting rainwater, and preventing pollution of water. To prevent further shortages, households, communities, and private industries can adopt water saving practices, some of which are given below.
Households can save water by promptly fixing leaks or dripping taps: Although the water lost from leaks may not seem like much, it adds up to quite a lot. A dripping tap can result in a loss of upto 72 litres of water every day.
Recycling of water is very important: We can start this even in our homes. For example, water used in cleaning utensils can be used to water plants in the garden instead of being poured down the drain.
A lot of water is lost during floods: Dams, reservoirs, and embankments will help to check floods and the flow of water.
Floods
By improving the methods of irrigating the fields: Instead of filling up the entire field with water, farmers can be taught the method of watering the roots of plants drop by drop. Israel, which is a water-scarce country, has come up with this innovative technique called drip irrigation. This type of irrigation employs the method of watering the roots of the plants drop by drop. This saves up to one-third of the water that would otherwise be lost during spray applications. Further, it enables farmers to double harvests using the same amount of water. In other countries, such as Egypt, some solutions suggested are improvements in water efficiency and moving away from water-intensive crops.
A typical irrigation dripper
Building Dam A dam is a structure built to hold back water in order to prevent floods, and to provide water for irrigation and storage. Building a dam is a solution to both drought and flood. Dams are also used in producing electricity. Built on rivers, a dam has high walls and has many openings or gates to both let in and hold back water. During heavy rainfall, when the rivers fill up, water enters the dam. When water is needed later, the gates are opened to let out water.
A dam
Preventing Water Pollution Another method to conserve water is to safeguard our fresh water bodies from pollution. Garbage and harmful chemicals pollute the water and make it unfit for use. Polluted water is also very bad for aquatic life. Plants and animals in and around polluted water may die or get infected. And when human beings consume the contaminated fish, etc., they are also put at risk of diseases.
Water pollution caused by harmful chemicals and garbage
Avoiding Wastage at Homes Some ways to avoid wastage of water at homes are given below.
Inform the municipality or call a plumber if you spot any leaking pipes in your neighbourhood.
Take water in a bucket for your bath instead of using the shower. A bath in a tub uses the largest amount of water. Always remember to shut the tap tight after each use.
Do not leave a tap running while brushing your teeth.
Instead of using running water for washing utensils, soak them first in one tub or sink and wash them in another, using a thin trickle only to rinse off.
Use a wet cloth to clean the car instead of using a hose.
Water plants and grass early in the morning so that the water gets absorbed before the sun evaporates it. Watering by hand saves a lot of water as against using a hose.
Repair all leaky pipes and taps.
Try not to throw away used or extra water down the drain if it can be used for some other purpose, e.g., you could use water remaining in your water bottle to water the plants.
Rainwater Harvesting Systems
The process of collecting and storing rainwater from roofs or a surface catchment is called rainwater harvesting. Storing rainwater that collects on roofs instead of letting it go down the drain, is a practical solution in case of droughts. This technique is known as rooftop rainwater harvesting. This involves collecting rainwater from rooftops in dugout ponds, vessels, or underground tanks to store water for long periods. Another option is to allow water to go into the ground directly from the roadside drains that collect rainwater. The stored rainwater is treated before use because it may contain bird faeces, chemicals, and other pollutants, which need to be removed before use. These help us to use rainwater directly. These structures are designed to help capture and store rainwater during the monsoon season, and serve as a source of drinking and irrigation water during the rest of the year.
Diagrammatic representation of a typical water harvesting system
In the southern states of India, tanks, artificial ponds, and reservoirs have been constructed as part of the water harvesting system. These do not make a significant contribution to the total freshwater resource in India, but water harvesting systems have a strong impact on a local scale.
Scarcity of water is defined as a situation where there is insufficient water to satisfy normal requirements. Though water is a renewable resource, we humans are using it at a faster rate than it is being replenished. There are various factors contributing to the depletion of the water table.
Increasing Population: Growing population has resulted in a growing demand for houses, offices, shops, roads, etc. As a result, open areas like parks and playgrounds are used for construction. This reduces the seepage of water into the ground. Moreover, construction work requires more water for which underground water is used. As the rate of consumption of underground water is more than seepage, it results in a depletion of the water table.
Increasing Industries: The rapidly growing population has also resulted in an increase in the number of industries. Water is used in almost every stage of production of things that we use. This has put a heavy load, especially on the freshwater ecosystem.
Agricultural activities: India is an agricultural country and farmers have to depend on rain for irrigating their fields. However, erratic monsoons result in excess use of groundwater thereby decreasing the underground water.
Deforestation: Trees have the ability to hold water. With deforestation, the number of plants decrease, hence the water keeps flowing towards the sea and the groundwater is not recharged.
In India, some causes of water scarcity are:
Uncontrolled use of borewell technology for extracting groundwater: Farmers have over exploited groundwater resources in our country due to uncertain monsoons and an unreliable state water supply. Pollution of freshwater resources: This is due to the discharge of untreated sewage from homes, toxic chemicals from industries, and of pesticides and insecticides used by farmers into water bodies. No effective measures for water conservation: Very little has been done for groundwater recharge and for care of freshwater ecosystems.
Effects of Water Scarcity on Plants
Water is very important for plant growth; its deficiency weakens the plant. When plants do not get sufficient water, they do not grow to their expected height, have reduced photosynthetic activity, and produce much less harvest than expected. Without enough water, plants will also be susceptible to diseases, which can eventually lead to the death of the plant. This may result in no food, no oxygen, no rain, and eventually end all forms of life on the Earth.
Water availability in India depends greatly on the seasonal monsoons. The monsoons bring heavy rain over most of the country between June and October. Only Tamil Nadu is the exception and receives over half of its rain from October to November. India ranges from places having waterless conditions (Thar Desert) to places with rainforest climate (North Eastern States). In general, the northern half of the country sees greater extremes in rainfall.
India has a large network of rivers too. The three ARABIAN major rivers, Indus, Ganga and the Brahmaputra originate in the Himalayas and drain nearly two- thirds of the land area. These rivers also account for nearly the same proportion of India’s total water resources. Water in these rivers is strongly influenced by the monsoons.
Rainfall map of india
During the monsoons, water levels in rivers increase greatly and may result in floods. On the other hand, during the dry season, water levels go down quite a bit in most large rivers. Smaller tributaries and streams generally dry off completely. To regulate water flow in these rivers and distribute water more evenly throughout the year, large dams have been built on a number of rivers.
On the other hand, the mountainous and hilly regions of north and west do not allow adequate seepage. So, groundwater is mostly limited to lower-lying areas such surrounded by water on three sides as valleys. The peninsular areas of our country also do not allow proper absorption of water, and therefore do not have large continuous aquifers. Though the coastal plains are a rich source of groundwater, they can be contaminated by saltwater inflow caused by the over-pumping of groundwater. The Gangetic plains are, however, rich in groundwater as the aquifers keep getting recharged and restored.
Precipitation in the form of rain or snow provides fresh water to our planet Earth. Most of the fresh water returns to the oceans through rivers flowing across the globe. A small portion of it is absorbed by the soil and is stored underground. A still smaller portion is stored in natural (lakes and ponds) and man-made (tanks and reservoirs) water bodies. Thus, the various sources of water can be divided into two main categories:
Surface water
Underground water or subsoil water
Surface Water
Water present on the surface of the Earth is called surface water. It can further be classified into three categories depending upon the ‘purity’ of water. Rainwater: Rainwater is the purest form of water. Why? As water from the seas and rivers evaporate to form water vapour under the heat of the sun, it leaves behind all the impurities. When precipitation occurs, the first showers dissolve certain gases present in air and also bring suspended impurities along with it. Subsequent showers, however, consist of pure water. River and Lake water: The water in these water bodies comes either from rainfall or melting of snow (glaciers) on the mountains. Sea and Ocean water: Oceans are a huge store of water. Millions of litres of water is present in them. But the water is salty and is not fit for either domestic or agricultural use.
Underground Water or Subsoil Water
Groundwater is the water under the ground where the soil is completely filled or saturated with water. Rainwater seeps through topsoil and layers of rocks like limestone, sand and gravel, and gets collected on top of non-porous layers. The top level of this underground water is called the water table. Underground water is also known as an aquifer.
The place where the water table meets the land surface, water may come out of the surface in the form of a natural spring and flow into a lake, stream or an ocean. Groundwater that meets the land surface also keeps rivers, streams, and lakes filled with water. Wells can also be drilled to take out the underground water.
