Most people with their own backyard dream of having a pond. Not only does it beautify the household, but it also gives you a relaxing backyard.
While it is easy to dream about having a pond, actually building a pond and taking care of it is a different ball game altogether. One of the problems that pond owners face the most is deciding the best depth for their pond.
While most commonly 2-3 feet is the usual benchmark for the best pond depth, you have to take a lot of factors, such as surrounding temperature, oxygen levels and even the wildlife into account.
In the following article, I will discuss how to get the best depth for your pond, what factors do they depend on, and how you can make changes in some of your plans.
Deciding factors for pond depth
The best or perfect depth for your pond varies depending on a few different factors. They can differ in terms of climate, the animals or plants to be introduced in them, or even oxygen levels.
Depth on the basis of climate
Depending on where you live and the climate of that particular place, the depth of the pond you want to own will vary. The depth will be different for hot and cool climates.
The recommended depth for ponds is 2 to 3 feet. Although the minimum depth is said to be 18 inches, it is better to have a pond at least a couple of feet deep. This is because of the change in weather. A pond too shallow is susceptible to being evaporated in hot summers or being completely frozen in cold winters.
1. Pond depth for warm climates
If you are living in warm areas, you don’t want to have a shallow pond. Not only does a shallow pond get its water evaporated too easily, but it also results in an algal bloom. When provided with enough sunlight, algae grows very quickly and often, uncontrollably.
Too much algae in your pond will result in the fish and plants underwater not getting enough sunlight and oxygen. This will result in them dying off quickly. To avoid this catastrophe, dig a pond that is at least 18 inches deep. But to be on the safe side, it is better for the pond to be 2 feet deep.
2. Pond depth for cold climates
Although you won’t have to deal with algae or bacteria in cooler climates, you will have to struggle against the freezing temperatures. As you can not control the weather, once the temperature drops below the freezing point, the pond water will definitely freeze.
But, if the ponds are deep, only the surface will get frozen while the rest of the pond water will still be liquid. You can then deal with the frozen water using a pond de-icer. But if the pond depth is less than 2 feet, the whole pond will get frozen solid, making it harder to deal with it. So, dig a pond that is at least 2 feet deep.
Depth on the basis of Animal and Plant
Whether you want to raise fish, keep other animals or simply have aquatic plants, you have to maintain a depth according to the requirements of those specific organisms.
1. Depth for fish ponds
Most people want to have ponds in their backyard for the purpose of rearing various different kinds of fish. Unlike climates, where you had to dig up to one specific depth, fishes have specific depth requirements according to their specific species. So, you have to keep that in mind while digging ponds.
On average, the minimum depth for a fish pond should be 2 feet. Any shallower than that, your pond will be completely frozen during winter and be way too hot during summer. Both of these situations will result in the death of the fish in your pond. Not only that, shallow ponds will take less time to be filled up with the waste produced by the fish. This toxic waste is another reason for the death of fish in the pond.
For some fishes, even a two feet deep pond is a bit shallow. For example, Koi fish, which is probably the most common fish people keep in their backyard ponds due to their beauty, need a minimum of three feet pond depth. For keeping four koi fish, you will need a pond of around one thousand gallons of water volume. If you have limited space, dig the pond deeper. This will help you maximize the area while having more volume of water.
The depth of your pond will also depend on the number of fish that you want to keep in your pond. The more fish are there in a pond, the more the depth of said pond should be. A deeper pond will not only save your fish from the scorching sun but will also provide a place for them to hibernate during winter.
2. Depth for wildlife ponds
Wildlife ponds are an exception to the established rule of 18-inch minimum depth. Contrary to the fish ponds, wildlife ponds should be at best 12 inches deep. While fish ponds need to be deep, wildlife ponds should be shallow as well as wide. Because the purpose of wildlife ponds isn’t for them to live in the ponds, rather drink water and bathe in it. So if a pond is deep, there is every chance that smaller animals will drown in it.
Being shallow means that these ponds are going to be frozen solid during winter. But unlike fish ponds, you don’t have to worry too much. Because most animals who would have been dependent on the pond will probably be in hibernation during that time. Even in summer, when they will almost certainly evaporate, they will be automatically refilled at the time of rain. So these ponds will need the least amount of maintenance.
3. Depth for Plant enriched ponds
One of the best ways to keep your pond clean and healthy is to have plants in it. Depending on the type of plant you have in your pond, there should be different depths. As there are plants that need no water depth as they grow on the mud, there are also plants that need depths as much as five feet, which is considerably more than any pond that has fish in it.
Plants like water lilies prefer deeper waters such as three feet deep ponds. This preference also changes across various species. You can understand if the pond is too shallow for the species of water lilies if instead of laying flat on the water, its stalks and leaves stick out of it. These protruding leaves are susceptible to attacks by aphids, so it is better to do some research on the water lily species according to the depth of your pond.
Usually marginal plants need about 6 to 12 inches in depth. Some plants can be placed in the shallower parts of water, while some can even be placed out of the water.
The best way to incorporate different types of plants in a single pond is to dig the pond in various depths in different places. The edges should be shallow which gets deeper gradually.
For better understanding, here is a classification of plants according to their planting depths which will help you select plants for your pond.
- Bog plants: These plants don’t need any water depth as they grow in the mud surrounding the ponds.
- Marginal Plants: They need a depth of 0-10 inches.
- Deep marginal plants: They need a bit more minimum depth than marginal plants, as they grow on water that’s 6-10 inches deep.
- Submerged Plants: These plants grow underwater and need a depth of 12 to 24 inches.
- Floating plants: They don’t need any specific depth as they float on the surface.
4. Depth for Frog/Toad Ponds
Frogs and toads are one of the most beneficial animals for any ecosystem they are native to. Because of this reason along with the reason that they are a part of cuisines all over the world, people nowadays tend to rear frogs and toads in their ponds.
While digging a pond for frogs and toads, make sure the banks of the ponds are sloped. These slopes should be at 20° to 30° angles. The purpose of these slopes is to help the animals get out of the pond when they want to.
Remember, these animals are amphibians. They need to stay on both land and water, so if you take their option to stay on land, they will not survive.
The depth should be different in different places for the frogs and toads to live, swim and lay eggs in. The deepest part of the pond should be no less than 3 feet deep. This will help these amphibians to deal with the winter properly. Also plant some plants like cattails to provide much needed shed for them.
They are cold blooded, so they can not regulate their body temperature like us mammals. So, you need to make the surroundings as suitable for them as possible.
5. Depth for Turtle Ponds
Turtles are one of the most trending animals that are being kept in ponds at present. There is a sense of calmness about them which is transmitted to whoever is having them in their backyard ponds. They also make a pond stand out from other traditional ponds.
For turtles, the minimum depth should be at least 2 feet. But it is recommended that you dig a pond that is twice as deep. Also, it is better to make the pond sloped from one end to another.
This will help the turtles to be able to get out of water to sunbathe. Sunbathing is an important part of their lives as these reptiles need the sunlight to warm their cold blood up. Also, do not have any aquatic plants in the ponds as the turtles will eat them. Also, as they are very curious creatures, it is not recommended to have skimmers in your pond if you have turtles in them as well. Also, put your pond pumps inside wet walls.
Depth on the basis of Oxygen Levels
Deep ponds are double-edged swords when it comes to dissolved oxygen levels. Dissolved oxygen is key to the survival of the fish in your pond. So if your pond has low levels of dissolved oxygen, you can kiss your fish goodbye.
Shallow ponds are the best way to keep the oxygen levels high. But fish prefer deeper ponds than shallow ponds as we have established earlier. So, on one hand, deep ponds provide the perfect habitat for the fish while on the other hand, they have low levels of dissolved oxygen which is detrimental to their health. So, how can you solve this dilemma?
One way to fix this problem is to install a fountain or an air pump into the pond. Both of them are aerators, which is a kind of device to move the pond water, increasing the dissolved oxygen levels.
If you have ponds that are two to six feet deep, you can use surface aerators. But, if your pond is deeper than that, you must use a subsurface aerator, which might put a larger dent in your wallet.
Pros and Cons of deep ponds
Though deep ponds are usually the better option, it is not without their drawbacks. Let’s take a look at some of the pros and cons of having a deep pond.
Pros of deep ponds
- Deep ponds have temperatures that are more suitable for plant and animal lives.
- Ponds that are deep can have different depths in different parts, making them able to accommodate different kinds of plants.
- Deep ponds are mostly immune to sudden changes in the weather.
Cons of deep ponds
- Deep ponds have lower dissolved oxygen levels.
- Sometimes ponds that are too deep don’t have enough sunlight for the necessary plants & algae to grow.
Now that you know how to get the best depth for your pond, it should not be too hard for you to figure out the ideal depth for your pond. No matter what the purpose of your pond is, make sure to follow the guidelines provided above and you will have to deal with one less problem while maintaining your pond.