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Lake Chad

Lake Chad is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lake Chad rather than just read about it. In short: Lake Chad (Arabic: بحيرة تشاد, Kanuri: Sádǝ, French: Lac Tchad) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon, in western and central Africa respectively, with a catchment area in excess of 1,000,000 km2 (390,000 sq mi). It is an important wetland ecosystem in West-Central Africa.

Lake Chad — main illustration
Lake Chad — illustration

Key takeaways

  • Lake Chad belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Lake Chad to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Lake Chad from memory before moving on to harder problems.

Reference excerpt

Lake Chad (Arabic: بحيرة تشاد, Kanuri: Sádǝ, French: Lac Tchad) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon, in western and central Africa respectively, with a catchment area in excess of 1,000,000 km2 (390,000 sq mi). It is an important wetland ecosystem in West-Central Africa. The lake is rich in aquatic resources and is one of the important freshwater fish- producing areas in Africa. Lake Chad is divided into deeper southern parts and shallower northern parts. The lake's main source of water is the Chari River which has many tributaries. The water level varies greatly seasonally, and the area of the lake also changes dramatically. In the 19th century, it still had an area of 28,000 km2 (11,000 sq mi). However, due to climate change and human water diversion, the lake shrunk significantly between 1960 and 1990, the open water area decreasing from 25,000 km2 in 1960 to just 2000 km2 in 1980. The lake is now no longer estimated to be shrinking, as rainfall recovery has partially occurred. Despite the stabilisation of the lake's water volume, Lake Chad is still under threat from climate change.

Prehistory and history

The Chad Basin was formed by the depression of the African Shield. The floor of the basin is made of Precambrian bedrock covered by more than 3,600 m (11,800 ft) of sedimentary deposits. For most of the Quaternary, the basin had abundant water sources. Towards the end of this period, the climate became drier. Around 20,000–40,000 years ago, eolianite sand dunes began to form in the north of the basin. The area of Lake Chad experienced four heydays between 39,000 BC and 300 BC, leaving thick diatomaceous earth and lacustrine deposits in the strata. This has been called Mega-Chad. The maximum depth of Mega-Chad exceeded 180 m (590 ft) and it covered an area of approximately 400,000 km2 (150,000 sq mi), it flowed into Benue River through the Mayo Kébbi, which drains into the Atlantic Ocean through the Niger River. The vast waters formed during the African humid period provided conditions for the emergence of lakeside fishermen's settlements, and the Nilo-Saharan ethnic group also migrated to Lake Chad during this period. Agriculture also emerged in the Sahel region at this time. By 1800 BC, a pottery culture known as Gajiganna had emerged, initially as pastoralists, but, starting around 1500 BC, living in settled hamlets at the side of the lake. The archaeological discovery revealed wild grasses, mostly of the tribe Paniceae, and wild rice together with the earliest domesticated Pearl millet in the Lake Chad region, dating to 1200–1000 cal BC. One of the oldest domesticated Pearl millet in West Africa was found in the Chad Basin, charred together with wild grasses, and their era can be traced back to 800–1000 cal BC. Permanent villages were established to the south of the lake by 500 BC, and major archaeological discoveries include the Sao civilization. According to the records of Claudius Ptolemy in the mid-2nd century AD, the Romans of the 1st century AD had already come into contact with Lake Chad through their connections with Tunisia, Tripolitania, and Fezzan. By the 5th century AD camels were being used for trans-Saharan trade via the Fezzan, or to the east via Darfur. After the Arabs conquered North Africa during the 7th and 8th centuries, the Chad Basin became increasingly linked to the Muslim countries. Trade and improved agricultural techniques enabled more sophisticated societies. Around 900 AD, the Kanem people who spoke the Kanuri language unified numerous nomadic tribes and established the Kanem Empire in the northeast of Lake Chad. At the beginning of the founding of the country, the Kanem people continued to live a nomadic life until the 11th century, when they were Islamized and settled in Njimi. Through trans-Saharan trade, the power of the Kanem Empire reached its peak in the 13th century, but as the empire declined in the 14th century, its southwestern vassal state of Bornu began to rise, causing the power center of the empire to shift to Bornu around 1400. In 1574, the Ottoman Empire had invaded Fezzan and the Oasis, and even reached into Lake Chad. This was the deepest Ottoman incursion into the interior of Africa before the nineteenth century. The Ottoman Empire extended its influence on the central region of the Sahel during the reign of Murad III. Lake Chad became a part of the Ottoman sphere of influence, and in the second half of the 16th century, the Bornu Empire began importing firearms from the Ottoman Empire, consolidating its military hegemony. The Bornu Empire declined in the 18th century, and later lost its western region to the Sokoto Caliphate during the early 19th century. It was later colonised by European powers in the 20th century. Following the growing interest in Africa among European academic and business communities, the Lake Chad area was extensively described by Europeans in the 19th century. Three scientific expeditions were conducted between 1898 and 1909. During the Berlin Conference in 1884–1885, Africa was divided between the European colonial powers. By the second decade of the 20th century, Lake Chad had been colonized and occupied by Britain, France, and Germany, defining boundaries that are largely intact with the present post-colonial states. At the beginning of independence, the countries surrounding Lake Chad not only had a poor economic foundation, but also had more complex ethnic, religious, and political conflicts. Nigeria and Niger, which had just gained independence, experienced continuous coups, while Chad also experienced ongoing civil war. The inability of countries along the lake to consider the protection of Lake Chad has led to a series of environmental problems.

Geography

… excerpt ends here. Continue reading the full article.

Illustrations

Lake Chad illustration
Lake Chad: Lake Chad in African humid period (blue) and in 20th century (darker green surrounded by blue)
Lake Chad in African humid period (blue) and in 20th century (darker green surrounded by blue)
Lake Chad: Map showing the Chari River drainage basin
Map showing the Chari River drainage basin
Lake Chad: Shrinking of Lake Chad over the last 7000 years, with the outline of the British Isles for size comparison
Shrinking of Lake Chad over the last 7000 years, with the outline of the British Isles for size comparison
Lake Chad: Lake Chad 1972–2007
Lake Chad 1972–2007

Worked examples

Example 1 — a first encounter with Lake Chad

Start with the simplest possible case. Write down what Lake Chad claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lake Chad before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lake Chad ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lake Chad

In research
Lake Chad appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Lake Chad in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Lake Chad is common in secondary-school and first-year university syllabi. It links to neighbouring topics Border tripoints, Cameroon–Chad border, Cameroon–Nigeria border, so understanding it makes those chapters shorter.
In everyday life
Look for Lake Chad outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lake Chad in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Lake Chad means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Lake Chad out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lake Chad in simple terms?

Lake Chad (Arabic: بحيرة تشاد, Kanuri: Sádǝ, French: Lac Tchad) is an endorheic freshwater lake located at the junction of four countries: Nigeria, Niger, Chad, and Cameroon, in western and central Africa respectively, with a catchment area in excess of 1,000,000 km2 (390,000 sq mi). It is an impor…

Why does Lake Chad matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lake Chad?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lake Chad.

Tags

  • Border tripoints
  • Cameroon–Chad border
  • Cameroon–Nigeria border
  • Chad–Niger border
  • Chad–Nigeria border
  • Ecoregions of Africa
  • Endorheic lakes of Africa
  • Flooded grasslands and savannas
  • Geography of Central Africa
  • Important Bird Areas of Chad
  • International lakes of Africa
  • Lake Chad

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