Incorporating a pond into a permaculture design has a number of benefits that it brings to the site as a whole. There is the obvious function of providing the site with a body of water. Not only can this contribute to irrigation of the plot, but it can also affect nearby microclimates (as water absorbs and releases heat from the sun more slowly than the surrounding land, as well as reflecting sunlight), attract different species of wildlife, and add another aesthetic dimension to the plot. Here are some of the things to consider when designing a pond for your permaculture garden.
One of the central features of permaculture design is the maximization of edges. This refers to the locations where two different ecosystems come up against one another. Each ecosystem benefits from the interplay between the two that these edge zones – sometimes called ‘ecotones’ – provide, and they are typically among the most productive and biodiverse locations on a permaculture site. The edge principle can be applied to pond design by using a non-standard shape that has lots of inlets and spurs. A pond with a ‘wavy’ perimeter has a lot more edge than a circular one. This increase in the amount of edge allows for the use of a greater number of plants, which will have the knock-on effect of attracting a wider variety of insects, birds and amphibians.
With a pond, the edge effect can actually be applied in three dimensions. Varying the depth of the pond provides a greater variety of niches for aquatic plants and animals to populate. For instance, some plants prefer their roots in the water but their leaves above the surface, while other float on the water. Tadpoles and small fish seek shallower water than larger fish and crustaceans, while having at least one area of deeper water in your pond provides relief for all inhabitants in times of high temperatures, which is when water levels can drop. You might also consider having an island in the middle of the pond. This jut of land, being surrounded by water, will have a slightly different microclimate even from the pond edges, offering another growing environment. This variety of depth is why ponds that are dug and then lined with a flexible material are preferable for permaculture plots than prefabricated ones.
The large amount of edge on your permaculture pond should allow you to plant a wide variety of plant species around the perimeter of the pond. As with the rest of the plot, choose native species whenever possible. This variety will not only provide different habitats and food sources for insects and animals, it will also add to the visual appeal of the pond. You should also plant a variety of species in the pond itself – from those in the shallows to fully submerged species. This creates more habitat niches and helps to keep the water healthy and oxygenated.
Left to its own device a body of water such as a pond will attract animals from across the local area, particularly if it is a permaculture pond that emphasizes biodiversity and so offers a lot of plant life. This will bring in lots of terrestrial as well as aquatic insects which it turn will bring in frogs, lizards and birds. If you want to stock fish or crustaceans such as mussels and shrimp, you will need to introduce them. Choose species that occur naturally in the area, as they will be best suited to the local conditions, and source from a reputable organic supplier so the animals have not been treated with any inorganic compounds that could enter your pond’s ecosystem.
For ponds – especially newly created one – that receive a lot of direct sunlight, weed and algae growth can be a problem. These can block sunlight from getting to the water beneath the surface, preventing the plants there from photosynthesizing and so starving the pond of oxygen. Adding plants that overhang the edges of the pond can help, by preventing sun from getting to the entire surface and so lowering the overall temperature of the pond. This shade is also beneficial for animals in the pond, providing shelter for smaller creatures from predators and the elements.
Another way of providing fish and other water life with protection is to place stones, logs, stumps and other natural features in and around the pond. As with plants, have some fully submerged, some partially in the water, and others on the land around the perimeter. This also creates more habitat niches that different species can thrive in. Avoid using prefabricated inorganic items in your pond, to avoid introducing unwanted chemicals and other potential contaminants.
Probably the best time to dig a pond is in the fall, after the first few rainfalls. This means that the ground is soft enough to dig easily, and the pond can fill up naturally with rainwater and snow over the fall and winter months. Your pond should be a natural ecosystem, so it will ebb and flow, with the water level dropping in summer when more evaporation occurs, and rising again when the temperatures drop. If the pond is in danger of drying out completely – which is unlikely expect in the most drought-affected areas – do not use tap water. The chemicals that are used to treat water in the municipal system can upset the balance of your pond’s ecosystem. Harvest rainwater for the purpose.
If you have small children, it is a very good idea to erect some form of barrier around the pond to prevent them from falling in. Indeed, in some locations a barrier around a body of water is mandatory as part of local regulations. The best form of barrier for your children and your pond is one made from chicken wire. Ell staked, a chicken wire will still have some give in it so that it won’t hurt anyone bumping or falling into it, but the holes in the fence will allow plants to grow through and enable animals to traverse the barrier.