Curious How much having structure like a barrel affect water temperature in the winter and summer. Such as shade in summer and minimizing water movement on the fish inside the barrel in the winter. I’m sure depth probably plays a factor. Thanks
If you aerate and mix the water in the pond during the Summer, I expect negligible effects. A barrel in water shallow enough to have significant sunlight penetration may have a notable shade effect as you suspect.
Minimizing water movement for a fish in a barrel in the Winter will not have any impact like getting out of the wind does for us.
I suspect esshup will post shortly; he may have done temperature studies on this phenomena and have empirical data.
I suspect (keyword - suspect) that any submerged shade structure will have little to no affect on actual water temps. Anything that shades the bottom will reduce the temp of sallow bottoms and give the underlying inhabitants some relief from the sun's radiant heat, but the structure will still heat up itself hence heat the water around it as well. The only shade structure that would/could noticeably reduce water temps would have to be above the water surface.
Reflective submerged structure could reflect some light/heat back out of a pond, but, as we all know, submerged structures all turn grungy after a short period and the reflectiveness would soon disappear and become an absorber of the light's heat.
All in all, I believe the water temps would remain unaffected, but shade structure can certainly produce areas where the pond creatures can escape the radiant heat of the sun which is good for the dog days of summer in the warmer climates. Even though they can not escape the water temps at their preferred DO levels...they can get out of the sun and enjoy the shade.
Have seen an above water shade (very big tarp that rolled out) used for summer refuge. It went from shore to about 50 ft out , a foot above the water. It covered water depth from 0 to 15 ft deep and had submerged structures below. Fish could pick best DO level. It was well used but did not effect water temps much.
Like fish congregating under docks.
Without a way to control water movement in a pond its a pointless exercise. You won't really get much benefit at all. Not enough to make a difference. The only way to help is to do what ewest said, roll out a tarp or shade cloth.