**Explanation:**

A hydraulic jump is a phenomenon that occurs when a high-velocity flow abruptly transitions to a lower-velocity flow. It is commonly observed in open channels, such as rivers and spillways. The height of the hydraulic jump refers to the difference in water surface elevation between the upstream and downstream sections of the jump.

The hydraulic jump can be characterized by different flow parameters, including the initial depth, sequent depth, alternating depths, and conjugate depths. Among these parameters, the difference in conjugate depths is directly related to the height of the hydraulic jump.

Here's a detailed explanation of each parameter and why the height of the hydraulic jump is equal to the difference in conjugate depths:

**1. Initial Depth:** The initial depth refers to the water depth upstream of the hydraulic jump. It is the depth of the flow before it encounters the jump. While the initial depth influences the occurrence and behavior of the hydraulic jump, it does not directly determine its height.

**2. Sequent Depth:** The sequent depth refers to the water depth downstream of the hydraulic jump. It is the depth of the flow after the jump has occurred. Similar to the initial depth, the sequent depth does not directly determine the height of the hydraulic jump.

**3. Alternating Depths:** The alternating depths refer to the water depths at different locations within the hydraulic jump. These depths vary along the jump, with the water surface rising and falling as the flow transitions from high velocity to low velocity. While the alternating depths are essential for understanding the flow characteristics of the jump, they do not provide a direct measure of its height.

**4. Conjugate Depths:** The conjugate depths refer to the water depths at specific locations within the hydraulic jump, where energy loss is at a minimum. These depths are crucial for analyzing and designing hydraulic structures, as they represent the stable flow conditions within the jump. The difference in conjugate depths, which is the difference in water surface elevation between the upstream and downstream conjugate depths, directly corresponds to the height of the hydraulic jump.

In summary, the height of the hydraulic jump is equal to the difference in conjugate depths. This parameter represents the change in water surface elevation between the upstream and downstream sections of the jump and is essential for understanding and designing hydraulic structures.