If you invest time and money in your pond, adding a cover will greatly enhance your enjoyment of it. Pond covers are expensive, if done by professionals. But there is a simple do-it-yourself version made of arches which will look terrific, and help keep debris and leaves from getting into the pond, making clean-up easier.
Calculate the number of arches you will need by measuring your pond. The arches of the pond cover will be made of metal conduit pipes. You should figure one arch to every 90 or 105 cm (3 or 3 1/2 feet) of the perimeter of the pond. It is important that your measurements be precise so that you figure the number of arches correctly. If there is any doubt, take the measurements again.
Measure the width of your pond using the carpenter’s tape measure. Do this at the widest point. This measurement will determine the height of your arches. The arches must be 60% of the width of your pond. So a 3 m (10 foot) wide pond would need an arch 1.8 m (6 feet) high or more, but never less.
Take each of the 1.5 m (5 foot) long galvanised conduits. Dig holes 60 to 75 cm (2 to 2 1/2 feet) deep. These should be placed 90 or 105 cm (3 to 3 1/2 feet) apart. If you have a great deal of snowfall, you can place them closer. Place the 1.5 m (5 foot) lengths of conduit in the holes, angled towards the pond, all the way around.
Place your arches starting at the widest part of the pond and going to either side of the pond. Attach the pieces of 3.1 cm (1 1/4 inch) PVC conduit by placing the male end into the female end of the 1.8 cm (3/4 inch) conduits you just placed. The ends should fit perfectly. You might need more conduits if you have a larger pond. Make each successive arch shorter by a bit so there is a gradual arc; cut pieces, if necessary, to fit the desired height. The final cover will then be dome-like. You should have a series of inverted ‘U’s when done.
Position the 1.8 cm (3/4 inch) PVC conduit on top of each arch to serve as the "spine" of your pond cover. Attach the conduit longways to the centre of the arches using twist ties and duct tape. Make sure the spine is attached securely. Push the rebar into the ground at both ends of the pond cover. Slip the end piece of the spine over the rebar. If it doesn’t reach, add as much of the 1.8 cm (3/4 inch) conduit as you need to secure it to the rebar.
Lay the plastic over the frame horizontally. Continue to do this down the length of the frame. Overlap each piece by folding over the piece next to it and smoothing from one end to the other. Do not trim too much from the extra length of the plastic. Rather, leave plenty so that you can secure the plastic with bags of sand or rocks or concrete blocks. Make sure you secure the plastic well. No part of the ground around the bottom should be showing. Pull firmly as you secure the second side.
Use brightly coloured or patterned plastic to brighten up the winter.
Do not use concrete mix as a weight. It will be ruined during the first storm. Shovel snow from base of the cover after each snowfall.