Which of the following statements regarding river meanders is/are correct? 1. It is a U-shaped bend in a river. 2. An extremely tight meander is called a goose neck; it is likely to become a cutoff, or oxbow lake, after a flood. 3. Tectonic uplift can cause a river to continue downcutting along its meandering course, producing incised or entrenched meanders. Select the correct answer using the code given below.
1, 2 and 3
River Meanders Explained
This solution delves into the characteristics and formation processes of river meanders, addressing the statements provided regarding their shape, evolution into oxbow lakes, and the impact of tectonic activity.
Statement 1: Meander Shape
The first statement describes a meander as a U-shaped bend in a river. This is an accurate description of the sinuous curves or bends that form naturally in a river's course, especially in its middle and lower stages where the river gradient is gentler and lateral erosion is more dominant than vertical erosion. The characteristic 'S'-shape of a meandering river is composed of multiple such bends.
Statement 2: Gooseneck Meanders and Oxbow Lake Formation
The second statement correctly identifies an extremely tight meander loop as a 'gooseneck'. This occurs due to the continuous process of erosion on the outer bank and deposition on the inner bank of a meander. Over time, the outer bank erodes, making the bend tighter and the neck of the meander narrower.
During periods of high flow, such as floods, the river's velocity increases, accelerating erosion across the narrow neck. Eventually, the river may breach the neck, taking a straighter, more direct path downstream. This event is called a 'cutoff'. The abandoned meander loop becomes isolated from the main river flow, often filling with water and sediment, forming a crescent-shaped lake known as an 'oxbow lake'.
Statement 3: Incised Meanders and Tectonic Uplift
The third statement accurately links tectonic uplift to the formation of 'incised' or 'entrenched' meanders. Tectonic uplift refers to the process where the land surface is raised relative to sea level due to movements within the Earth's crust. When tectonic uplift occurs in an area where a river is already meandering, it increases the river's gradient and its erosive power.
Consequently, the river begins to cut vertically downwards into the landmass while maintaining its existing meandering pattern. This downcutting action carves the river valley deeper, resulting in meanders that are set into the landscape with steep valley sides. These are known as incised or entrenched meanders, reflecting the river's history of lateral migration followed by renewed vertical erosion.
Conclusion on River Meander Statements
Based on the analysis, all three statements provided offer correct descriptions of key features and processes associated with river meanders:
- Statement 1 correctly defines the basic shape of a meander bend.
- Statement 2 accurately describes the evolution of tight meanders ('goosenecks') into oxbow lakes through the process of cutoff formation, often accelerated during floods.
- Statement 3 correctly explains how tectonic uplift can lead to the formation of incised or entrenched meanders by causing the river to downcut along its established meandering course.
Therefore, all the given statements accurately reflect geomorphological concepts related to river meanders.
Similar Questions
Which one of the following lakes in India has a large quantity of a substance found in the Moon?
Indus river basin is extended up to
Which two rivers flow in the region between Gulbarga and Vijayanagara Hampi?
What will be the correct sequence of cities on the bank of river Ganga if someone moves from west to east?
Rani told her friends that last year she did boating in four different lakes, namely, Loktak, Barapani, Kolleru and Pulicat. Which of the following States did she visit?
Which one of the following is a tributary of Barak River in Manipur?
Match List I with List-II and select the correct answer using the code given below the lists:
List I (Lake) List-II (State) A. Kaliveli 1. Sikkim B. Khajjiar 2. Kerala C. Khecheopalri 3. Himachal Pradesh D. Vembanad 4. Tamil Nadu When the rivers discharge their waters from all directions into a lake or depression, the pattern is known as
Which one of the following tributaries of river Indus feeds the canal system of the Bhakra Nangal Project?
Which one of the following rivers joins Ganga directly?
Important Questions from Indian Rivers and Water Resources
Which major river flows between the Vindhya and the Satpura Mountain ranges?
The major portion of river Mahanadi lies in the state of_________.
Som is a tributary of -
Which one of the following lakes in India has a large quantity of a substance found in the Moon?
Which is the longest tributary river in India?
