letting nature back in

A wildlife-friendly pond even in a suburban garden can really enrich the space. Although we still provide bird baths, which are heavily used, a pond with aquatic plants adds another dimension, attracting other creatures in addition to the birds.

When planning a garden pond, the first consideration is where to locate it and what size to make it – dependent on the ground available and what you want to take on. Ponds do best if they are in the sun for at least several hours of the day. Obviously, very sloping ground is not appropriate for a pond. We found a slight natural depression just below our house, perfect for a pond, and situated so that we have a good view of it from our back deck.

Depending on the space available, a pond can be as big or small as you like.  Smaller ponds cost less and are easier to manage. Even a tiny pond can provide habitat for a variety of life

A wildlife-friendly pond needs at least one side that is secluded enough for birds and other animals to approach without undue disturbance, and at least this side of the pond should be shallow with a gently sloping “beach” to provide a place where birds can bath. Also should any animal fall in, it has a chance of gaining a foothold in the shallows enabling it to escape to safety.

On the subject of safety, bear in mind that even small ponds can be a drowning hazard for young children. Visiting children must be supervised at all times, and it is best for a pond to be visible from the house and not tucked away out of sight. If there are resident children under the age of five, consider a safety net or metal grill over the pond, as well as surrounding the pond with a fence that a child cannot climb over or crawl under.

Red-backed Mannikins enjoying one of the shallow areas of our pond. Small rocks provide additional perching places for birds to drink from 

Although ponds need at least one shallow “beach”, there also needs to be a deep enough area to regulate the temperature of the water. The deepest part of our pond is about a metre in depth so that in our summers the deep water remains relatively cool. I expect that in climates with very cold winters, the water needs to be deep enough so that only the surface freezes.

Choosing the material used to line a pond depends on a variety of factors, not least of which is cost. Many garden ponds are lined with thick plastic sheeting. We decided against this option as we were concerned that dogs taking a dip in the pond may puncture the lining with their claws.

We considered the possibility of using clay, which is the traditional method, but we do not have suitable clay in our area, and anyway, without farm (or wild animals) to help with puddling the clay and maintaining the health of the pond it would not be practical.

I have read that some people install small fibre-glass pre-made ponds at a sloping angle so as to create a shallow end and a deep end, filling in sections with rocks or cement to level it off .

After much debate, we built the pond using bricks and cement, reinforcing the foundations of the sloping areas with wire mesh. Oh yes, I nearly forgot to mention the digging part. Digging the pond took my husband more than a few weekends. Once it was constructed, he then lined the pond with a bitumen sealer (Laykold) using membrane in sections that he thought needed strengthening. This worked perfectly for a few years, but unfortunately some plants escaped their containers and their roots perforated the sealer resulting in the pond developing a slow leak.

Sealing the pond with bitumen sealer. The underwater “shelves” are where we place submerged potted water plants

When the pond eventually started a slow leak in the deep end, we had to make a second smaller “dormitory” pond for the Banded Tilapia that we had introduced into the pond. Once this pond was ready we transferred the fish to this second pond so as to be able to drain the original pond. This process turned out to be a complicated and drawn out saga that soaked up many weekends.

The small channel between the two ponds could be sealed off by a metal plate that could be screwed into place and then sealed round the edges – my husband’s bright idea this – so as to be able to separate or isolate the ponds should one need draining for repairs. The top edge of this metal plate is visible in the picture above. The larger pond on the right had recently been refilled after repairs to the bitumen sealer had dried.

The two ponds with the vegetation still needing to recover after the repair work

After a few more years, the pond sprang another leak. This time the new bitumen did not cure and after we complained, the manufacturer compensated us by giving us a slurry concrete sealer that did the job, and (touch wood) it is still leak free. Although it is expensive it is probably the best sealer and several non-toxic brands are available for ponds.

The new sealer took about two weeks to dry. In the photo above, the newly sealed pond is being refilled. The fish are in the smaller pond on the left. However, we decided the fish were too high maintenance and so they were relocated. Once the fish had gone, rather than maintain the second pond, we filled it in and turned it into a bog garden

The original pond, after being resealed is looking rather bare as the vegetation still needs to regenerate. The second pond has been filled in and planted up with bog plants. The pond is fed by rain water and when full it overflows into the bog

Another important consideration for a pond is that the water needs to be well oxygenated. In a small pond it is possible to accomplish that with oxygenating plants, but we have found that we do need a pump to circulate the water, and in the process the water gets piped to flow over a homemade cascade, which serves to aerate the water and produce the tinkling sound of falling water, another attractive feature of a pond.

By balancing rocks we were able to create a small cascade. Some of the rocks were given to us from a building site and others were collected from roadworks in a river valley. Some rocks have been completely submerged to provide hiding places for creatures that live in the water

There are many local aquatic plants to discover and adopt for your pond. Wherever you are it is very important not to use invasive alien water plants that are notorious for clogging up our waterways

 I hope all this does not sound off-putting! It was the fish that caused the complexity that caused us to make an additional pond. We have had the original pond for 14 years and it only had minor leaks twice, and that was with the bitumen sealer and not helped by some rather robust plants that have now been relegated to the bog garden.

I really do recommend a wildlife-friendly pond as we have so enjoyed ours (and it is much easier  now without the fish!). But if a pond seems a bit ambitious you can always consider a water feature as a kind of a compromise. There are many water features that can be adapted to provide safe watering spots for wild creatures.

 Posted by Carol