Dear Ravinder,

I'm sorry, I'm not an expert of glacial fed streams, but I would like to share the following thoughts.

Since we observe a flow of water, we can assume that its temperature shall be above 0°C. Based on the origin of the water, it could be warmer due to either geothermal heating, for instance. Several meters below the ground surface we will probably have a ground temperature which reflects the long-term mean near surface (eg 2m) air temperature. So also the water coming from these parts shall have a similar temperature. A major difference between a stratified lake and a stream is the turbulent mixing due to the flow over uneven ground. Hence we shall have a more or less equal temperature in the stream. Hence the density anomaly of fresh water should not stratify the stream.

In addition, water has quite a high heat capacity, so I would require high heat fluxes to change the phase of water. Here the energy loss that is needed to cool the water from +2°C to 0°C is much lower than the energy loss needed to change the phase from liquid to solid.

On the other side, the near surface air temperature is correlated to the local radiation balance. For conditions favoring low temperatures (high elevation, high albedo, for instance) you can certainly observe low temperatures; for a complete picture you have to consider also the horizontal advection of air masses and/or vertical air motion.

In my humble opinion, you could easily find the described conditions.

Thank you Sir...

I was referring to the lake stratification in context to low air temperature that will cause the upper epilimnion to freeze while lower layers would maintain their temperature and don't freeze.

rivers and streams don't have that sort of phenomenon due to rapid mixing of water and thus maintain almost uniform temperature as u said sir, that means streams maintain water temperature above 0°C in conditions having lower air temperature below 0°C.