The eclipse got me to thinking about how nice it would be if we could shield our pond from the blazing sun, especially in summer. Good weed control, temp refuge. I remember that on False River near Baton Rouge, temps were up to 20F cooler in summer under docks.

Is there an economical way to do this? Does anybody make large shields for this purpose?

PS I no longer own a pond, but the new owner wants input & good ideas.

I’ve never checked temp on shade(under a dock) and compared

The only thing I can think of is the shade cloth that they use out in California. You can buy it by percentage of sun blocked. It'd need some pretty strong posts to hold it up off the water over the spans that he'd need though. They used it to shade some growing fields there, but it's easy to put posts close together when not over water.

I actually contemplated that topic a long time ago when I was wondering if I could get tasty cool-water fish like Walleye and Yellow Perch in a warm Kansas pond. (I think researching pond topics then may have been what introduced me to Pond Boss!)

I think a structurally fixed shade cover would work, but it would be very expensive. And it would have to be re-purchased every few years because I have seen the ones around here at restaurants and swimming pools get destroyed by heavy winds.

I think(?) my best idea was to make giant floating circles of black polypipe (like a giant feeding ring) and cover the top edge with white "billboard vinyl". The re-purposed vinyl is very cheap (less than $0.20/sq. ft) and is pretty tough stuff designed to survive wind and sun. You also need to screw in some floats in the middle underneath the vinyl to reduce sagging and ensure an air gap beneath your entire structure.

Even white vinyl will heat up in direct sun. But you do NOT want that direct solar radiation being absorbed by the darker objects on the pond bottom or in the water column. Instead, the air gap beneath the vinyl will get quite hot, but air is a poor medium for conductive heat transfer. Even better would be to have a significant number of small holes in the sun cover. As the air gap heats up, it could then vent back out. You also need some holes so rain water does not pool on the tops and stretch out (and ruin) your vinyl.

I was even thinking of getting material that was black on the reverse side. In the winter, you could flip the circles over and have black material under maybe an inch or two of water just soaking up the solar radiation.

Enough of these pond covers would actually reduce evaporation from the pond. That would be good for preserving that water level in ponds that are frequently water starved. However, evaporative cooling during the summer does remove a LOT of heat energy from a pond. That is why your sun shades need a certain amount of small holes. You must allow a significant amount of evaporation to have a net cooling effect as a result of your sun shades.

Being directly on the water, I think this type of structure would last much longer in windy areas because very little wind would be getting underneath the material and making ripples that "snap" with the right harmonics.

Fortunately, Pond Boss people taught me that I didn't need such elaborate schemes to grow WE and YP in warmer waters!

Don't know if there is anything in that crazy idea that might be helpful, but I thought I would type it up anyway. You could always try to experiment at small scales and get some data.

Thanks to everyone for the replies. Rod, a special thanks to you. I'd thought about this before but never really put together a workable plan. The new pond owner is a mechanical engineer, so may be very interested!

Engineer pond owner? My prediction, prototype coming soon to a pond near you!