You can winterise your pond by creating a dome over the top of it that will protect your fish from extreme temperatures and help reduce ice formation. The dome pond cover creates a greenhouse over your pond which allows fish and plants to survive in the colder months. This dome cover is easy to create and you can disassemble and reuse it over and over again. Before beginning this project, install an aeration kit and deicer or an air pump if your fish are staying outside for the winter.
Determine how many arches your pond needs. You will need one arch for every 3 feet. Make stakes for the arches by cutting ¾-inch galvanised conduit into 5-feet sections with a pipe cutter or hacksaw. Make two stakes for each arch needed.
Place stakes every 3 feet around one side of your pond. Angle your stakes slightly toward the centre of the pond. Hammer the stakes 2 feet into the ground with a mallet. Go to the other side of your pond and hammer the stakes into the ground in the same fashion. Make the stakes parallel to one another across the pond. Mark the stake on both sides of the pond that is midway the length of the pond with a marker.
Calculate the height of the arches by multiplying the pond's width by 0.6 because the height of the arches needs to be at least 60 per cent of the width. Make the centre arch by cutting a piece of 1 ¼- inch PVC electrical conduit to the arch height. Put male and female ends of the conduit together to make arches longer if needed. Make the rest of the arches you need by making the arches progressively shorter than the first arch.
Create arches over the pond that digress downward from the centre arch to make a dome. Slide one end of the longest arch over one of the stakes that is in the midpoint of the pond. Slide the other end of the arch over the parallel stake on the other side of the pond. Form the remaining arches in the same fashion with the next arch shorter than the last.
Drive a 4-foot long piece of rebar at each end of the pond. Hammer the rebar into the ground 1 to 2 feet with a mallet. Create a spine for the dome by attaching a ¾- inch PVC electrical conduit to the tops of each arch. Run the conduit over the highest point of the arches long ways so the conduit touches the tops of each arch. Attach the conduit to the arches with zip ties and duck tape. Use a ladder to reach the top of the arches if needed. Slide each end of the conduit over the pieces of rebar at each end of the pond.
Cover the dome with 6mm plastic sheeting or a heavy duty tarp so all sides are covered and there is extra sheeting on the ground. Put rocks, concrete blocks, or sand bags on top of the sheeting or tarp all around the pond to anchor it down. Make sure you have plenty of weight on top of the extra sheeting so it does not blow away in the wind.
Have a friend help you to put the sheeting over the dome.
Shovel show from around the pond to avoid snow from piling up and ripping the plastic sheeting.