Correct Answer - Option 3 : to achieve ultimate stability of river with the aid of river training measures.
Concept:
River Training:
River training means adopting various measures on a river to stabilize the river channel along a certain alignment for the given/planned cross-sectional dimensions.
Objectives:
- Provides a safe passage to flood discharges without overflowing to the bank for protection of the cultivated or inhabited area.
- Prevent outflanking of structures like a bridge etc.
- Protects the banks from erosion and improves alignment by stabilizing the river channel.
- Deflect river away from the bank which it might be attacking.
- To provide a sufficient draft for navigation as well as a good course for it
- Ensure efficient disposal of sediment load.
The river training can be classified as follows:
1. High water training: It aims at providing sufficient river c/s for safe passage of maximum flood and is concerned with making the adjoining area flood proof, by construction of dykes or leaves, etc.
2. Lower water training: Its primary purpose is to provide sufficient water depth for navigation during lower water periods. It may be accomplished by concentrating and enhancing the flow in the desired channel by closing other channels.
3. Medium water training: It aims at efficient disposal of suspended load and bed thus preserving the channel in good shape.
