Water Bodies

Diagram showing the the hydrological cycle is given below:

Most of the world's water is being recycled by this continuous process called the hydrological cycle or the water cycle.

1. The Sun heats up the water bodies. The water evaporates as water vapour, which being light in weight, rises in the air.
2. On reaching the higher, colder levels of the atmosphere, it cools and condenses into tiny water droplets that join to form clouds.
3. When the clouds become too heavy and cannot remain suspended in the air, it comes down as precipitation such as rain or snow. Rain is the biggest source of fresh water on the Earth.
4. Some of the rainwater seeps underground, some fills up depressions to form lakes, while others just flow into rivers and streams, which carry water to the oceans.
5. The cycle is then repeated.

Ocean currents play a major role in shaping the climate on the Earth. Warm ocean currents keep cold coastal areas ice-free and also bring in moist winds that shed rain. Cold ocean currents, on the other hand, make a place colder and drier.

The meeting of the cold and warm ocean currents brings rich fish food called planktons, and hence these areas develop as ideal fishing grounds. For example, Grand Banks off the coast of Newfoundland in North America is the meeting place for the cold Labrador and the warm Gulf Stream currents.

Oceans are sources of renewable energy such as tidal energy and ocean thermal energy.
Oceans have vast reserves of minerals such as petroleum, magnesium, bromine and salt.

Lagoons such as Chilika in the state of Odisha in India are saltwater bodies with a narrow opening to the sea. They are separated from the sea by a sandbar.

Canyons are deep, narrow valleys with steep sides formed by rivers cutting through hard rock over a long period of time. When a river is young and flows quickly through mountains, it erodes the land vertically, creating deep V-shaped valleys called canyons or gorges. Example: The Grand Canyon in the USA, carved by the Colorado River.

During monsoon, rivers often overflow their banks and flood the surrounding land. As the floodwater recedes, it leaves behind layers of fine, rich silt. Over time, these deposits build up to form flat and fertile areas called flood plains, ideal for farming.

As the river comes out of the mountains, it enters the flat, levelled plains where its speed is no more as rapid as before. This is called the middle course. Now, the river swings from bend to bend forming loops known as meanders.

Two characteristics of a river in its lower course are as follows:

1. The river becomes very slow and begins to deposit silt and sand in between the course of its flow. This sometimes leads to the formation of permanent river islands.
2. The river forms a delta, or sometimes an estuary, where it meets the sea.

Rivers are valuable to farmers because:

1. They bring fresh silt to make fertile plains, which are excellent for growing crops.
2. The water of rivers is used to irrigate agricultural fields.

Water bodies are fast degenerating, primarily due to human activities. Some of which are enumerated below:

1. Household wastes — Domestic waste water is mixed with other wastes such as plastic, detergent, animal dung and human excreta and is together known as municipal waste. This pollutes water bodies.
2. Industrial wastes — Factories produce toxic wastes which when discharged into water bodies, pollute the water and cause irreparable harm to aquatic creatures.
3. Agricultural wastes — Agricultural wastes mostly consist of fertilisers and pesticides. They may be carried off from the farms to the rivers and lakes as surface runoff during rains or floods. They pollute the aquatic ecosystem by promoting rapid growth of algae and subsequent depletion of oxygen in water.
4. Oil spills — Crude oil is transported across oceans in tankers. Accidents and leakages often cause oil spills that damage the marine ecosystems. Offshore drilling operations also contribute to oil spill.

Differences between Bays and Gulfs:

Differences between Tributaries and Distributaries:

Differences between Deltas and Estuaries:

A-3, B-4, C-1, D-2

a delta

a lagoon

Both (A) and (R) are true and (R) is the correct explanation of (A).

Explanation — Rivers begin their journey from the mountains. Meltwater from glaciers, springs or rainwater gives rise to rivers.

Both (A) and (R) are true but (R) is not the correct explanation for (A).

Explanation — Deltas are formed at the mouths of distributaries (narrow river branches) when they enter the sea, and Flood plains are formed from silt, deposited after flood water recedes. However, floodplains and deltas are different landforms formed in different parts of a river's course.

(A) is true but (R) is false.

Explanation — Mountains are often made of hard rocks. Hence, deep V-shaped valleys called gorges or canyons are created by a river due to its speedy course in the mountains, not because mountains are formed of soft rocks and get eroded fast.

1. The Ganga Plain grows food for millions of Indians because its rich fertile plains, formed by the deposition of fertile alluvium, support the growth of diverse crops.
2. Ganga is a perennial river as it is a glacier-fed river and carries water throughout the year. River Ganga originates from the Gangotri Glacier in the Himalayas.
3. Besides farming, river Ganga provides irrigation facilities to the crops grown nearby and helps in the generation of hydroelectric power as it flows throughout the year.

The water crisis in the world is due to the following reasons:

1. Abundance of Salt Water — About 71% of the Earth's surface is covered with water, but 96.5% of it is saline and found in oceans and seas, which is not suitable for drinking or irrigation.
2. Limited Freshwater Availability — Only about 3.5% of the Earth’s water is freshwater. However, most of this is not easily accessible:
   • Frozen in glaciers, ice caps (Arctic, Antarctic)
   • Stored underground in deep aquifers
3. Tiny Share for Direct Use — Just 0.5% of freshwater is found in rivers, lakes, and ponds, which is the primary source for all human, plant, and animal needs.
4. Pollution by Human Activities — Many freshwater sources are being polluted by industrial waste, sewage, agricultural runoff, and plastics, making the water unsafe and reducing the usable supply.
5. Overuse and Waste — Water is often wasted through careless usage, leaking pipelines, over-irrigation, and excessive extraction from rivers and underground sources, especially in urban and agricultural areas.
6. Unequal Distribution — Freshwater is unevenly distributed across the world. Some regions face scarcity while others have relatively abundant resources.

Thus, despite the Earth's water-rich appearance, the actual usable freshwater is extremely limited. Human pollution and wasteful practices are making the situation worse, leading to a growing global water crisis.

EXPLORER I —

• Name : Christopher Columbus
• the country she belonged to : Italy
• the expedition which made him famous : Discovery of the new lands of Americas while searching for a sea route to India
• the year in which it was done : 1492
• the discord that followed (if any) : Columbus's voyage led to the European colonization of the Americas
• any landmark named after him : Columbus city in the USA

EXPLORER II —

• Name : Vasco da Gama
• the country he belonged to : Portugal
• the expedition which made him famous : First European to reach India by sea via the Cape of Good Hope
• the year in which it was done : 1498
• the discord that followed (if any) : Conflicts with local rulers and traders on the Indian coast
• any landmark named after her/him : Vasco da Gama city in Goa, India

EXPLORER III —

• Name : Ferdinand Magellan
• the country she/he belonged to : Portugal
• the expedition which made her/him famous : First expedition to circumnavigate the globe
• the year in which it was done : 1519-1522
• the discord that followed (if any) : He was killed in the Philippines before completing the journey
• any landmark named after her/him : The Strait of Magellan in South America

1. The picture shows a canyon, specifically the Grand Canyon formed by river Colorado in Arizona.
2. Canyons are formed in the upper course of a river.
3. The river flows with great speed in its upper course due to the steep slope.
4. Another river feature formed during the upper course is a waterfall.