Pond Design
Designing a pond is the easy part. Building a pond takes a little more. First of all, clear out a space in your yard for the pond. Remember this one thing at the beginning, no matter how large of a pond you make, it will shortly be apparent that it should have been larger. If it is a water garden with no fish, it is not nearly the problem, but if you plan to have goldfish, make sure it is large enough for the number of fish you will want to accommodate. Fish need a lot of water to stay healthy, and goldfish tend to be messy. A good filtering system is necessary.
You can stake out the general plan, or spray paint the ground in the shape you want it. Ponds can be square, round, oblong, or free-style and natural looking. Ponds can be made of block, brick, natural rock, even glass block. Doing a search online for other styles would be good to get a better understanding of what you want, and how to do it. Ponds can be dug into the ground (such as ours) or set on ground level. The in-ground style is better for the fish because the temperature doesn't fluctuate with rapid changes of weather as much.
If you plan on keeping koi, remember they can and do outgrow the size of their environment, while goldfish do not. If you want to keep goldfish and koi together, just remember that they do inter-breed, and you will end up with only goldfish, because the koi eggs will be eaten by the goldfish. They should be kept separate if you want any success with breeding.
If you want to keep koi, the smallest size of pond would be 1,000 gallons. It was recommended to me by my landscaper that buying a larger filter than the size of pond we have was the way to go. Our pond is only 1500 gallons, but the filtering system could easily work for a pond about 2000 gallons.
Our new 1500 gallon pond shortly after it was finished, but before planting the garden area. We began digging this one ourselves, but at that point, we decided a professional landscaper was in order. We hired one which specializes in ponds, and we were happy we did. He did an outstanding job on the waterfall, the plumbing, and the paved stone. He had experience with the make-up of the pond that we didn't have. However, with enough reading, and advice from those who have done their own pond, it is possible to do-it-yourself entirely.
To keep koi, the pond must be at least 3-1/2 feet deep. This one is exactly 3-1/2 feet deep, though I wish it were at least 4 feet deep. Also, shade should be provided for the pond, at least part of it, because fish can get sunburned if it is open to sunshine all day long in the summer. We designed our pond to have a "bog" side, or a shallow side to keep the plants. This end (on the right) is only 2-1/2 feet deep with a shelf around the edge for potted plants. It pours into the deeper side (on the left) with a small waterfall. The main and much larger waterfall is on the left to the backside of the pond, which provides a refreshing water sound that cannot be beat. There is another smaller waterfall on the right backside near the pond equipment that keeps the bog side filled. I have been keeping baby fry goldfish on the bog side, and it is large enough for small fish, too, according to my landscaper. We just have to make sure there is enough areas that are protected there, places to hide, because of the possibility of predators.
It seems that when people come to see it for the first time, the first thing that amazes them are the diversity of rock throughout the pond.
We added lots of flowers and a bench, which our cat really appreciated. The pond takes on a natural process that first year to balance itself out. Still, one must work hard to keep the pond healthy for the fish that live there. Weekly water of 10% changes are a must, and also the UV light which kills excess bacteria in the water.
There was a point we had too much planted in the bog side of the pond. We removed the pennywort (center and back), as it was much too prolific, but we kept the parrotfeather (at the sides). I do not recommend pennywort, as our landscaper later told me that once that takes over your yard (and it will), there is no way to remove it. The pennywort also added a lot of slime and foam to the pond. When it was removed, and the UV light cleaned up, the foam problem was lessened, and the water cleared up.