The Devonian Gardens form an indoor park located on the third level of Calgary’s The Core shopping center. Open since 1977, they incorporate a huge variety of plant life, a children’s playground, and fish filled ponds, spanning over a hectare of space.
When I was little I remember visiting the park regularly. It was free, offered a relaxing space to walk around (even in the freezing winter), and held regular events for families during holidays. By far my favorite aspect of the indoor garden has always been the fish ponds. The Devonian Gardens incorporated several impressive water features; housing Koi, Catfish, and some exciting spaces even boasted Trout and Turtles. Feeding them and watching them splash about in their frenzy was very entertaining, and fed my enthusiasm for nature and the animals that inhabit it.
Over three decades have passed since the park’s original construction, and in the last five years there has been a major revamp of the space. Originally it provided a dense network of winding paths between trees, sculptures, and streams. The new gardens are wide open, expanding on the style of the adjacent food court, and catering to potential meeting spaces and rental areas for businesses.
I’m not here to critique the park’s new style though. What concerns me more is the radical change which the ponds have undergone, and potential negative effects on the fish living there.
For those who haven’t visited the gardens, seen above are a before and after image of the types of water features found there. The former incorporated natural pond-like styles, fountain heads, and plenty of moving water features between the sections. The new version consists of a few large shallow pools. They are tiled, barren, and provide very little turbulence in the water.
There are three things which had a negative effect on my impression when I visited the new gardens: coins, poor water circulation, and an intense accumulation of algae and detritus.
The first problem admittedly, is not solely the responsibility of the developers at the gardens, it involves the patrons as well. In the 90’s when fewer people were aware of how harmful coins can be for fish, I might have been more understanding, but that is not the situation now. Attitudes have changed, and it is common knowledge that by tossing those coins into the Koi's water source you are hurting them.
So why is it still happening? Well, there will always be a few apathetic people who just don’t care, but I don’t think most of the visitors here are being willfully harmful to the Koi. On that first visit to the newly visited gardens I remember exclaiming “where did the ponds go?” This is because the new designs actually look much more like pools or mall fountains than traditional fish ponds. Couple that with the much sparser concentration of fish (A very responsible move on the garden’s part that I applaud), and it is easy to miss the little guys if they happen to be in a corner or hiding in the shadows.
The second thing that worried me was the lack of water circulation in many of the pools. While a few had fountain heads, many had next to no water movement. The old setup was full of spraying water, faux waterfalls, and streams; all creating turbulence and providing an efficient oxygen exchange at the water’s surface. Understandably, now that the location has been re-planned for business meetings and space rentals they do not want the roaring sound of water features to obstruct conversation. But aside from the risk of low oxygen levels in the water, it would benefit them to add at least some form of movement even if only to cut down on the unsightly scum that sits on the water’s surface for patrons to see.
The last thing that stood out to me was the explosion of algae and detritus accumulating in the ponds. It is not so much the algae itself that concerned me when visiting the gardens, but what it indicates. Typical green algae in small amounts in not harmful and can actually be beneficial in aquariums and ponds. But excessive growth can serve as an indication of an accumulation of something else that is.
Before going on I’m going to give an EXTREMELY simplified explanation of the nitrogen cycle for those who aren’t familiar with it.
By looking at the concentration of algae, we can see in indication of very high levels of nitrates (and also possibly phosphates, but I’m not going to get too complicated here)
In addition keeping these nutrients down for the fish’s sake, cutting the algae down would also make the area more appealing to visitors.
I'm not here just to be negative though, and what point is there in pointing out flaws if you don't offer some possible solutions? Here is what I would recommend:
The Coins:
There are a few ways I believe this problem could be cut down without having to police people or observe them at all times. First, making the existing fish ponds a little more pond-like through the addition of plants or natural features would make it more obvious to visitors that this is a fish habitat and not a wishing fountain. They could even consider singling out one particular fountain as a designated coin recepticlel, encouraging people to use that one and distinguishing it in some way.
Adding other signifiers for the fish (in case people don't see them in time) would also help to draw attention to them- eg. through the use of coin operated food dispensers as was done in the old model. While I recognize issue of overfeeding, this could be reduced by A: improving the filtration as I will discuss next, and B: increasing the cost of food, which will cause people to purchase less as well as collect funding for maintenance.
Water Circulation:
This is really an easy issue to fix. The first potential way to improve the water circulation without making any major changes to the design would be to add more fountain heads, thus disturbing the surface of the water. Should the potential noise be an unacceptable factor, addin powerheads beneath the water's surface would be quiet, easy to hide, and non invasive.
Algae and Detrius:
There are a few things which can be done to reduce algae growth in the Gardens, all beneficial to the fish and the appearance of the ponds. 1: Introduce aquatic plants to compete with the algae for nutrients. With the addition of aquatic or semi-aquatic plants, the nitrates and phosphates will be drastically reduced, cutting down on the algae food supply. Once the algae is down to a more manageble level, the Plecos (algae eating fish) living with the Koi can manage the rest. In addition, Koi and Goldfish greatly enjoy having shade and places to hide under so the plants would be good for their comfort as well as physical health.
It is true that Koi and goldfish enjoy eating plants, but their overconsumption can be avoided by A: choosing a rapidly reprodicing plant such as duckweed which will grow quickly and replentish itself as it is eaten. B: choosing plants that Koi do not find tasty such as hornwort, or C: choosing semi-aquatic plants where the roots and stalk sit submerged in a pot, and the rest of the plant protrudes safely out of the fish's reach.
The next way step in reducing the nitrate and algae levels involves removing the waste that accumulates in certain areas of the pond instead of reaching the filter. This could be done manually(via gravel vacume or python system), or the dead zones could be fixed through the use of the earlier items mentioned which improve water agitation so it can reach the filter for collection.
The third way to greatly cut down on the nitrates is through simple frequent water changes accompanied by regular algae scrubbing. As the concentration decreases, less and less manual algae removal will be necessary, and the water removed makes excellent fertilizer for tropical plants due to the same nutrients that cause algae blooms.
I last visited the Devonian Gardens a week ago, and will be submitting a refined proposal related to this article after I get some feedback. I would love any input from readers or to hear if you have had similar experiences/successes with other venues.
<>< Cheers, and Swim On ><>
