Lower course As a river enters the lower course, it slows down, splitting into smaller streams called distributaries. Any remaining sediment it is carrying is deposited in an area referred to as the delta. River deltas are commonly fan shaped, arrow shaped and bird-foot shaped. A delta’s shape is influenced by tides, waves and the volume of sediment and water carried by the river. Some rivers end with a wide mouth where fresh water mixes with salt water. This is known as an estuary .
Did you know? Australia has no major river deltas because of the strong ocean currents surrounding the continent.
13.5 SkillBuilder activity GEOGRAPHICAL INQUIRY
A river finishes its long journey at the delta. Here, the river deposits the material it has carried, creating landscapes with nutrient-rich soils. Agricultural activity is common in these regions due to the high quality of the soil. However, life in the delta is not without its hazards, as floods occur frequently in these regions. 1. Research river deltas around the world, paying closer attention to the positive and negative aspects of living in a delta region. 2. When you have completed your research, create a table which identifies and explains the costs (negative) and benefits (positive) of living in a delta.
FIGURE7 Salvaging crops after a flood in Bangladesh
13.5
Exercise
Learning pathways LEVEL1 2, 3, 4
LEVEL2
LEVEL3
1, 5, 6, 7
8, 9, 10
REMEMBER AND UNDERSTAND 1. Identify the correct statement.
a. The Nile River is 1.8 times longer that the Murray–Darling River. b. The Murray–Darling River is 1.8 times longer than the Nile River. c. The Nile River is 2.3 times longer that the Murray–Darling River. d. The Murray–Darling River is 2.3 times longer than the Nile River. 2. Study FIGURE5 . Identify the feature, other than water, that has to be present for waterfalls and rapids to
develop. a. W inds b. Soft rocks c. Bands of hard rock d. Heavy rainfall
TOPIC13 Landforms and landscapes – diversity, significance and management 303
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