Muttart Conservatory's Rainwater Harvesting System
One of my favourite things about living in Edmonton is the fact that I'm just 20 minutes away from the Muttart Conservatory. The Muttart's pyramids are an easily recognizable landmark and are a great spot to visit, whether you're an elementary school class on a field trip or a group of friends looking for something to do on a Sunday afternoon. Because it is one of my favourite places in the city, I was very excited to find out about the conservatory's Rainwater Harvesting System, which was an Emerald Awards finalist in 2016. Recently, I've been thinking a lot about my relationship with water and water use so I was super interested in getting an inside look at the system. So, on a sunny day to June, I headed to the conservatory to meet Garrett Watson and Dorothy Jedrasik to learn more. They gave me a tour of Greenhouse C, where the system is located, walked me through the steps of the rainwater harvesting system and talked to me about the future of environmental initiatives at the Muttart.
A Look at the System
The Rainwater Harvesting System is one of a few environmental initiatives taken on by the Muttart to reduce their environmental impact. It was first initiated as a collaborative effort with the City of Edmonton's Drainage department, who were looking for a way to control rainwater before it hit the sewer systems.
"[Drainage] was looking for facilities that have a high non-potable water demand," said Garrett Watson, an environmental analyst for the City of Edmonton. "We identified irrigation as one of the big demands for water use and [they] had a program to reduce stormwater runoff. So it was kind of the perfect fit".
Housed in Greenhouse C, the gravity-fed system is comprised of a long pipe that runs from outside of the greenhouse, twenty-one 625 litre tanks, and 2 filters to clear the water of larger debris and pathogens. The long pipe runs directly into the first filter and is lined with heat tape in order to collect snow melt in the wintertime.
After the water passes through the pipe into the first filter, it then continues to the a large filter, fondly known as the Big Bubba. It's in the Big Bubba that the most important filtration work is done--its job is to get rid of the small particles and pathogens that prevent the water from being usable. The Big Bubba gets rid of most of these particles, and then a U.V. tube targets the finer particles before the water is ready for use.
Once the water is free of debris and pathogens, it is now potable water which can be used for watering plants, grey water (for things like flushing toilets and mopping floors), as well as drinking water. The process is quick, according to Dorothy Jedrasik, taking just a few hours before all 21 tanks are filled.
Despite it's size, the system is quite compact and sits neatly under two large tables. The plant troughs are then placed on these tables and the water from the tanks pumps up onto the tables for a more efficient irrigation process.
“[It] takes about 1/2 an hour to 45 minutes and the geraniums just wick up the moisture from the bottom up," said Jedrasik. "I can water [approx. 4800] geraniums in 45 minutes".
The switch from tap water to rainwater has also been beneficial to the quality of the plants. According to a University of Alberta study, the growing tables that used rainwater had a 60% greater seedling emergence rate. Furthermore, the quality of rainwater is closer to the ideal water quality plants need, according to Watson, which means there's less of a need for chemical buffers.
As well as being environmentally beneficial, the rainwater harvesting system has a positive community impact. All the flowers that are grown through the rainwater system are then distributed throughout the city as part of the beautification program.
While there are no current plans to expand the rainwater harvesting system to the rest of the conservatory, both the Muttart and the City of Edmonton are committed to making a positive environmental impact. “Muttart is doing a whole variety of environmental initiatives to reduce our impact," said Watson. "[We're] trying to promote horticulture to the public and do it as environmentally responsible as we can.”
As a government institution, the Muttart's commitment to environmental responsibility is especially inspiring for both individual citizens and communities at large.