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. 

The correct answer is 1, 2 and 3.

Key Points

• Meanders are sinuous bends or curves in a river channel, which form naturally as a river erodes the landscape in snake-like paths.
• While a U-shaped description is simplistic, meanders are indeed characterized by their winding or bending form, which can resemble a series of U-shapes or large loops along a river course. Hence, statement 1 is correct.
• An extremely tight meander, sometimes resembling a neck of a goose, hence termed a gooseneck, is prone to the natural process of cutoff, particularly during floods. This process creates an oxbow lake, which is a U-shaped water body left behind when the river finds a shorter course, bypassing the meander. Hence, statement 2 is correct.
• Tectonic uplift can indeed influence a river's behavior. When an area undergoes uplift, it can alter the river's gradient, prompting it to carve deeper into its bed rather than meandering across a floodplain. This process can lead to the formation of incised or entrenched meanders, where meanders cut deeply into the underlying terrain. Hence, statement 3 is correct.

 Additional Information

• Meander formation is primarily driven by the lateral erosion and deposition along the outer and inner banks of the river bend, respectively.
• The stream velocity is higher along the outer edge of a bend due to greater water depth, leading to more erosion; conversely, the inner edge experiences slower velocities, prompting sediment deposition.
• Oxbow lakes are important for biodiversity, serving as habitats for various aquatic and bird species, even as they represent a snapshot in the dynamic process of fluvial geomorphology.
• Incised meanders serve as a testament to the river's history, capturing the interplay between climatic, tectonic, and hydrological factors over geological time scales.
• The study of river meanders and their evolution is crucial in hydrology, river engineering, and environmental science, informing flood management practices and river restoration projects.