Today I built a winter pond cover to help hold in the warmth and reduce air to surface cooling due to wind. Sub freezing weather is expected this week so it will be interesting to see how low the water temp gets. I also painted all my above ground pipes a dark green which makes them less noticeable than the white PVC and they may absorb more heat on those sunny winter days.
I built the wooden frame cover using pine 2x4s and 2x2s and designed it to sit on the edges of my pond. I used untreated pine. Ten foot 2x4s span the long side (9 feet) and the 2x2s are notched into the 2x4s on the short side (8 feet). The finished frame is 10′ x 8′ and sits a few inches from the back wall/waterfall while the pump is running. The cross of the wood beams forms rectangles 28″ x 22″. The edges of the frame are joined using hanging bolts with wing nuts so I can disassemble it in the summer months, or I may use it as bird net frame to keep herons out.
I stretched 9’x12′ 2 mil plastic sheeting over the frame and used the wingnuts to hold down the plastic. The frame is raised at one end due to the height of the skimmer cover, but that also allows water to run off during rain. If it snows I will cover the frame with a tarp since I doubt the thin plastic will support the weight.
Total cost of frame materials, bolts and wing nuts, plastic, and paint was just under $50. It took about 4 hours to build mainly due to the notching of the 2x2s into the 2x4s.
UPDATE: Overnight temps reached 21*F with a howling wind, but the pond stayed around 48*F.
1/14/2012: upgraded plastic to 6mil and added duct tape to reinforce connection points. Increased size of plastic to about 10’x15′ which gives more overlap for wind resistance. Cost + $10.
