Question.
What is the Yazoo stream? Why are the Yazoo Basins areas of repeated flooding? Give examples of Yazoo streams/areas from various parts of the world.
( UPSC Geography optional 2024)
Answer.
A Yazoo stream is a tributary stream that runs parallel to the main river for a considerable distance due to the presence of natural levees, before finally joining it downstream.
The stream is blocked by the natural levee of the main river and is unable to join it directly.
The term "Yazoo" originates from the Yazoo River, a tributary of the Mississippi River in the USA.
Why Yazoo Basins Are Prone to Repeated Flooding:
Yazoo basins, the low-lying areas between the main river and its Yazoo stream, are highly susceptible to flooding due to the following reasons:
a) Poor Drainage:
The natural levees of the main river trap water in the basin, causing poor natural drainage.
Rainwater and floodwaters accumulate in the basin with limited outlets.
b) Backflow Effect:
During floods, the main river overflows into the Yazoo basin.
Water may backflow into the Yazoo stream, aggravating the flood condition.
c) Siltation & Blockage:
Over time, silt deposition raises the main riverbed, but not the Yazoo stream, increasing the elevation difference and making drainage even more difficult.
d) Prolonged Waterlogging:
Floodwaters often remain stagnant for weeks, affecting agriculture and settlement.
Examples of Yazoo Streams / Areas Across the World:
North America:
Yazoo River, Mississippi, USA – classic example.
Tensas River, Louisiana, USA – runs parallel to the Mississippi.
India:
In Bihar, rivers like the Burhi Gandak and Bagmati act like Yazoo streams running parallel to the Ganga River.
In Assam, some small tributaries of the Brahmaputra exhibit Yazoo-like features due to natural levees.
Africa:
Some tributaries of the Niger River in Nigeria display Yazoo characteristics, flowing parallel due to alluvial levees.
China:
Tributaries of the Yangtze River, particularly near the Dongting Lake region, are sometimes obstructed by levees and behave like Yazoo streams.
Conclusion:
Yazoo streams are a geomorphic consequence of natural levee formation. While they represent an interesting drainage pattern, they also make the adjacent Yazoo basins highly flood-prone. Understanding their behavior is critical for flood control, urban planning, and sustainable agriculture in riverine plains.
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