To provide an accurate answer regarding the rate at which the water is rising when the water is 4 meters deep, I need additional context. Specifically, I would need to know the dynamics of the system you are referring to. For instance, are you considering a tank being filled at a constant rate? Is there an outflow, or is it related to a natural body of water?
If you have a specific scenario or parameters (like the volume of water being added, dimensions of the tank, etc.), please share that information so I can assist you better!