Examkin

Question

Difficulty: MediumRelief, Physical Regions, and Drainage Systems of Nigeria

The upper course of the River Gongola in northeastern Nigeria initially flows northeastward toward the Lake Chad basin before turning sharply southward at Nafada to empty into the Benue River. Which of the following drainage phenomena is illustrated by this sharp change in the river's course?

  1. River captureAnswer
  2. B
    Fluvial rejuvenation
  3. C
    Dendritic confluence
  4. D
    Deltaic bifurcation

Answer

River capture
The sudden bend of the River Gongola near Nafada is a classic textbook example of river capture (stream piracy) in Nigeria. Headward erosion by an energetic Benue River tributary breached the watershed divide, capturing the upper Gongola, which previously discharged into the internal drainage basin of Lake Chad.

Step-by-Step Solution

1
Analyze the drainage feature described in the scenario
The River Gongola originally formed part of the Lake Chad inland drainage system, but its upper waters were diverted into the Benue River system via a sharp angle near Nafada.
Headward erosion by a steeper, higher-energy stream (the lower Gongola/Benue tributary) eroded through the watershed divide to tap into the neighboring stream channel.
2
Identify the geographical term for stream interception
The process of a river breaching a watershed to divert the upper waters of a neighboring stream is called river capture (or stream piracy). The characteristic right-angle turn formed is known as the elbow of capture.
This is a key geomorphological concept explaining drainage network rearrangement in regional physical geography.

Key Concept

River Capture and Drainage Modification in Nigeria
Estimated Time:1m 0s
Rate this question

Topics

Relief, Physical Regions, and Drainage Systems of Nigeria

More questions from this topic