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In this lesson we are going to discuss about the types of lakes

Answer Text:
Lakes
A lake is a depression on the earth’s surface where water has accumulated.
Classification /Types of Lakes
-According To the Nature of Water
a) Fresh water lakes which contain fresh water.
b) Salty lakes which have salty water.
-According To the Mode of Formation of Depression They Occupy
1. by Earth or Tectonic Movements
a) Faulted or Rift Valley Lakes
- During Rift Valley formation some parts of the rift valley floor sunk more than others.
- A long narrow and deep depression formed.
- Water from seepage and rain accumulated into these depressions to form lakes.
b) Down Warped and Tilted Lakes

- Tensional and compression forces caused some parts of the earth’s crust to upwarp while others down warped.
- In the case of L. Victoria Rivers Kafu, Kagera and Katonga were tilted eastwards and Nyando, Yala and Nzoia continued flowing west wards
adding water into the depression.
- L.Victoria is the second largest fresh water lake after L.Superior.
- Has a maximum depth of 87m deep. Other examples of lakes are L. Kyoga and Wamala.
Playas/sebkha is a lake contained in an inland drainage basin in a desert formed when
rain or flood water flows into a basin formed by crustal warping e.g. Chemchane Sebkha in Mauritania.
2. by Vulcanicity
i) Crater Lakes
- Lake formed by water accumulating into a crater.
- Are usually salty.
- A crater lake formed on an explosion crater is called maar.
- Examples are Lakes Mossoko in Tanzania, Paradise in Marsabit and Myungu in Uganda.

ii) Lava Dammed Lakes

- Formed as a result water accumulating on the upstream side of a lava barrier across a river.
- Highly viscous lava erupts across a rivers course.
- It solidifies and blocks the river forming a lava dam.
- The rivers water accumulates behind the lava dam.
- A narrow and winding lake is formed e.g. Lakes Bunyonyi, Mutanda and Bulera in Uganda.
3. by Erosion
a) Glacial Erosion
(i) Corrie/Tarn Lakes

- Lake formed when water from melting snow accumulates into a corrie/cirque e.g. Teleki, Nanyuki and Hidden tarns on Mt. Kenya.
(ii) Ribbon Lakes
- Finger like lakes on a glaciated valley.
Formation
- Glacier erodes the floor of a u-shaped valley.
- It over deepens some of its sections.
- Elongated hollow results.
- Water from melting ice
accumulates into it forming a lake.

b) Wind Erosion
- Lakes formed when ground water accumulates in a depression formed by wind deflation and abrasion.
- Wind continuously erodes the earth’s crust by deflation and abrasion.
- The water bearing rocks are reached. Water oozes from the water table into the hollow or water from flash floods may
accumulate in it to form temporary lakes called pans e.g. in Quattara depression between Egypt and Libya and Etosha
pan in Namib.
c) Solution Lakes
- Lakes formed when rain or ground water accumulates in depressions formed in limestone rocks when rain water
containing a weak carbonic acid dissolves limestone rocks e.g. Lakes Barber in Morrocco and Ojikoto in Namibia.
4. by Deposition
a) River Deposition
- Formed when river deposition occur cutting off a section of a pronounced meander e.g. oxbow lakes Shakababo and
Mukunguya at lower part of Tana.
b) Wave Deposition
- Lakes formed when wave deposition occurs across a rivers mouth or where the coastline changes suddenly enclosing a
body of calm water.
- Waves break at an angle.
- The long shore drift causes materials to be progressively arranged across a rivers mouth resulting in a body of calm
water called a lagoon/sound.
5. by Man
a) When dams are constructed across rivers, then water accumulates behind the dams resulting into a large man made
reservoir called man-made lake e.g. behind Seven Forks Dam and Lakes Volta in Ghana and Nasser in Egypt.
b) Barrage is a bank of earth or stones built across a river to provide water for farming.