Many people find that water in the garden gives rest and relaxation. So alone it can be a good reason to build a japanese pond. You can also build a pond to attract abundant wildlife or because you want a swimming lake or shallow play area for your children where they can dress around for hours. A pond requires a lot of work, both when it is to be constructed and when it is to be kept clean.
However, part of the work can be left to technical installations such as air pumps and water purification filters. A garden pond should be at least 10 square meters, as very small ponds tend to grow. The larger the pond, the easier it is to maintain a natural balance in it, so that the water does not become algae soup.
However, the pond should not be so large that it becomes too dominant in the garden. You can try your hand, either by drawing the pond onto a sketch of the garden, or by using a garden hose or the like. To mark the shape of the pond in the garden. Then you can get an idea of what size and shape the pond should have to fit the garden.