Lakes

General Information on Lakes

A lake is a natural or artificial body of water that is surrounded by land. Unlike rivers or seas, lakes are still or standing water bodies. They can vary greatly in size, depth, origin, and chemical composition.

Some lakes last thousands of years, while others are temporary and may dry up or become swamps over time. Many lakes are freshwater, but some are saline, especially in arid or enclosed inland basins.

Types of Lakes

1. Tectonic Lakes (Formed by Earth Movements)

These lakes form when land sinks due to movements in the Earth’s crust.

• Example:
  • Lake Baikal in Russia – deepest freshwater lake in the world.
  • Lake Tanganyika in Africa – very deep and long.
  • Wular Lake in India – formed in a tectonic basin.

2. Glacial Lakes

Created when glaciers erode land or deposit debris to block valleys.

• Example:
  • Great Lakes (Superior, Michigan, etc.) in North America.
  • Dal Lake and Nainital Lake in India – formed in glacial valleys.
  • Loch Lomond in Scotland.

3. Volcanic Lakes

Formed in volcanic craters or calderas after eruptions.

• Example:
  • Crater Lake in Oregon (USA).
  • Lonar Lake in Maharashtra, India.
  • Lake Toba in Indonesia – formed in a massive volcanic caldera.

4. Erosional Lakes

Formed when water or wind wears away land to form basins.

• Example:
  • Oxbow lakes formed by river erosion – e.g., parts of the Ganga basin.
  • Small rock basin lakes in granite areas.

5. Depositional Lakes

Formed when sediment blocks rivers or glacial material traps water.

• Example:
  • Lake Chad – formed due to river blockage by sand dunes.
  • Salt pans or playas in deserts.

6. Lakes Formed by Human Activity

Artificial lakes made for storage, irrigation, or hydroelectricity.

• Example:
  • Lake Mead (behind Hoover Dam, USA).
  • Gobind Sagar Lake in Himachal Pradesh (Bhakra Dam).
  • Hirakud Reservoir, Odisha.

7. Lakes Formed by Biological Activity

Sometimes lakes form due to the growth of vegetation or coral reefs that trap water.

• Example:
  • Lakes formed in coral atolls or by beaver dams in temperate forests.
    

Saline Lakes

Saline lakes are those that contain high salt concentrations, usually because they don’t have outlets. Water flows in but doesn’t flow out, so evaporation leaves behind salts.

• Example:
  • Dead Sea – extremely salty, shared by Israel and Jordan.
  • Great Salt Lake – Utah, USA.
  • Sambhar Lake – Rajasthan, India.
  • Lake Urmia – Iran.

Saline lakes are often located in arid or semi-arid regions, where evaporation exceeds precipitation.

Lakes and Man

Lakes play a vital role in supporting both natural ecosystems and human societies.

1. Transport and Communication

• Navigable lakes help connect remote areas.
• Example: Great Lakes-St. Lawrence Seaway in North America.

2. Industrial Development

• Lakes support industries needing large quantities of water (steel, paper, chemicals).
• Example: Industrial hubs around the Great Lakes (USA).

3. Water Storage

• Provide water for irrigation, drinking, and domestic use.
• Example: Gobind Sagar, Hirakud Reservoir.

4. Hydroelectric Power (HEP)

• Dams built on lakes generate renewable electricity.
• Example: Bhakra Nangal, Tehri Dam.

5. Climate Moderation

• Large lakes absorb and release heat, reducing extremes of temperature.
• Example: Areas around Lake Victoria (Africa) or Lake Michigan (USA).

6. Tourism and Recreation

• Lakes are scenic spots for boating, fishing, and tourism.
• Example: Dal Lake in Kashmir, Lake Geneva in Switzerland.