Building a trout pond can add a fun and interesting aspect to your life, but it should cater to their needs. Trout ponds can be quite large but should always include pumps and filters to keep the water oxygenated. You'll also need to watch the water temperature, since trout won't do well in water that gets too warm. Ponds can be constructed using black-plastic pond liners, available at pond-supply stores, using a couple straightforward steps.
Planning the Pond
Decide on your pond's location. Place the pond close to your house, where you can enjoy the sight and sound of it. Your pond should receive 4 to 6 hours of direct sunlight every day and be protected from runoff.
Determine the size of your pond. For trout, plan on a depth of at least 5 to 7 feet, with a capacity of 50 to 500 gallons. For a larger number of trout, the capacity should be around 400 to 500 gallons.
Design the shape of your pond and lay it out on paper. Calculate the length and width at the longest and widest points of your pond. Add the depth to each measurement, plus 2 feet, to determine the size of your pond liner. You should end with measurements like 10 feet long by 5 feet deep at the longest point, and 5 feet wide by 5 feet deep at the widest point.
Building the Pond
Dig your pond. Instead of a straight drop, give your pond sloping sides. If you want to keep water plants for your trout, leave a shelf around the edge of your pond, where the water is only 1 foot deep.
Line the pond excavation with pond underlayment to protect it from leakage. Avoid wrinkles in the underlayment.
Place your black plastic pond liner over the underlayment. Black plastic and rubber pond liners are available at pond-supply stores. Again, try to avoid wrinkles.
Place stone or edging around the edge of your pond to secure the pond liner. If necessary, mortar the stones into place.
Place your pump and filter inside the pond (some pumps might be better placed outside the pond; always follow the manufacturer's instructions). A pump and filter are necessary to keep the water properly oxygenated for the trout. Plan on buying equipment that can handle large amounts of water.