Main purpose of mean water training for rivers is A. Flood control B. To provide sufficient depth of water in navigable channels, during low water periods C. To preserve the channel in good shape by efficient disposal of suspended and bed load D. All of the above

The correct answer is D. All of the above.

Mean water training is a technique used to control the flow of water in rivers. It involves the construction of dams, levees, and other structures to alter the river’s course and prevent flooding. Mean water training can also be used to improve navigation and to preserve the river’s channel.

Flood control is one of the most important purposes of mean water training. Dams and levees can be used to hold back water during periods of high rainfall, preventing it from flooding downstream areas. Mean water training can also be used to improve navigation by providing a deeper and more stable channel for boats and ships. Finally, mean water training can be used to preserve the river’s channel by preventing erosion and sedimentation.

Here are some additional details about each of the options:

• Option A: Flood control. Dams and levees can be used to hold back water during periods of high rainfall, preventing it from flooding downstream areas.
• Option B: To provide sufficient depth of water in navigable channels, during low water periods. Mean water training can also be used to improve navigation by providing a deeper and more stable channel for boats and ships.
• Option C: To preserve the channel in good shape by efficient disposal of suspended and bed load. Mean water training can be used to prevent erosion and sedimentation, which can damage the river’s channel.