To design a backyard pond, decide where you want to place the pond, the size of the pond, and what kinds of animals and landscaping you want. Then, choose materials for the pond. Use a rope or hose to lay out the pond's shape, mark the ground, and dig to the desired depth. Decide if you want to have waterfalls, pumps, lighting or fountains, and ensure that electricity is available.
Begin digging the pond anytime when the ground is not frozen or overly wet. To prevent the water from seeping into the pond, use either a thick PVC liner or build the pond out of concrete. Keep in mind that some plastics are toxic to fish.
Aquatic plants grow best in sunlight, but sunlight also allows more algae growth. Plants such as water lilies help to control algae. Using a mix of emergent, submergent and floating plant species helps balance water nutrient levels. Some plants require a depth of at least 2 feet to grow. Deeper pond depth also allows for more variety of fish species.
Begin filling the pond slowly, and allow the pond to sit a few days for any chlorine to evaporate before adding fish and plants.
Your municipality may require the pond to be fenced in to reduce the risk of drowning. Lighting around the pond reduces the risk of falls.