We often get asked about keeping a waterfall running during the winter. Here where we typically have mild winters it is possible and we do keep ours running. One must use common sense when deciding if it is appropriate in their location. Obviously if you live in a place that gets hard freezes then don't keep it running. If you are able to keep it running in the winter here are a few things to watch out for just in case.
The running water is good during the winter if at all possible. If the water does start freezing, keep an eye on it. Once you start freezing in the fall watch to make sure the water is not diverted out of the fall or pond by the ice. This could quickly drain your pond and result in burning up your pump. Also if the waterfall continues to form ice and keeps freezing more and more, then you need to consider shutting off the pump.