Correct Option
The correct option is 1 only
Explanation
Floodplains are major depositional landforms produced by the action of running water (rivers). They are relatively flat areas of land adjacent to a river that are subject to periodic flooding. The deposition of sediments (alluvium) during these floods contributes to the formation and evolution of the floodplain.
Statement-wise Analysis
- Statement 1 is Correct: In geomorphology, specifically within the context of river deposition, the river bed itself, when composed of river deposits, is considered the active floodplain. This is because the materials in the bed are actively transported and deposited, forming an integral part of the dynamic floodplain system.
- Statement 2 is Incorrect: The floodplain area situated above the river banks is classified as the inactive floodplain. This area is elevated relative to the active channel and is not submerged during ordinary flood events, unlike the active floodplain.
- Statement 3 is Incorrect: Inactive floodplains are formed through the lateral shifting of river channels and vertical accretion. Consequently, they contain both channel deposits (left behind when the river channel shifted) and flood deposits (accumulated during overbank flooding events). They are not limited to channel deposits alone.
Key Takeaway
Key Takeaway: The active floodplain includes the river bed made of deposits, while the inactive floodplain lies above the banks and contains both channel and flood deposits.