Very reassuring. Thank you for the replies. Over many decades there was only one year where the pond froze enough to walk on it. Most years it does not completely freeze over.

Fish, the stream diversion does not run in winter. I might start diverting in future winters once I install a microhydro turbine, but except for that there is little benefit to bringing in more water in winter.

Having said that, the snowpack in our part of the Sierra Nevada mountains went to 180% of normal after the last storms. Very nice change from years of drought. We should have good creek water and much more healthy trees next year. More than 100 million pine trees have died state wide due to drought, drought related beetle problems, and fires.