How Rainwater Harvesting Transformed Our Urban Home, Part 1
This week, I want to go over a case study in rainwater harvesting design. This example is special to me because it’s about how we partnered with my mother-in-law to transform her property into a permaculture oasis.
Let’s roll back to the mid-2000’s. After traveling for almost four years learning about renewable energy, low-energy buildings, rocket mass heaters, rainwater harvesting, organic farming, and composting, we came back to Calgary and started working on the only land we had access to: my mother-in-law’s house. She encouraged us to redesign her home and property using permaculture principles, and the project proved to be the start of Verge. After 10 years the results are hard to believe—take a look!
Ground Zero in 2007…
This was what we started with: A 1970s bungalow on a 5,000-square-foot lot in east Calgary. The house was poorly insulated, had an ancient (and haunted, I swear) furnace, and the yard had been sprayed for years with weed and feed. It was a daunting first project, but we went in with a saying from Michelle’s mom:
You will overestimate what you can do in one year and underestimate what you can do in five.”
~Annette St. Cyr
I now use this saying all the time with my clients and keep it constantly in mind when I take on new projects.
Eight Years Later in 2015…
This photo is a few years old now but still really captures the transformation that has taken place in the front yard. The property now features a medicinal and edible food forest, a completely renovated and re-insulated home, an edible backyard with a cob oven, an outdoor kitchen, a passive solar greenhouse, and a complete rainwater harvesting system. We’re still innovating and making changes to this day.
In permaculture, water is the master element. If you get the water component right, everything else follows. When we first started, most of the water was hitting the roof and property and flowing away.
Why? Cities create drainage systems that remove water from the landscape almost as fast as it hits the ground. As soon as the rain is gone, we then spend vast amounts of energy pumping water back up to our homes. Did you know that the City of Calgary uses an estimated 30% of its energy pumping water and sewage? All because we start with a wrong initial design.
We have modelled our cities and subdivisions after deserts when we should have patterned them around forests.
On-site Rainwater Storage
We now capture close to 90% of the rainwater that hits the property either in tanks, in the ground, or utilize it to grow food. We have several types of rain storage, two of which are above ground and one that is below grade.
The above grade rainwater collection tanks are IBC totes, which I don’t recommend now (I’ll discuss why in a future article) and store 1,000L (200 gallons). The tote in the image below stores water for our greens bed, with the overflow feeding our food forest through a swale. The screen I’m holding in the image is called a “rain head” or gutter screen and is designed to prevent debris from the roof from entering the tank.
To install our second rainwater tank – a custom-built, below-grade rain cistern – we needed to overhaul Annette’ back yard, removing a strip of lawn perched atop a terrace. We excavated the space, put down a pond liner, installed a culvert to create voidage, then covered it over with a patio.
The rainwater storage tank stores roughly 3,000L (600 gallons) and meets the majority of the water needs of the passive solar greenhouse we built adjoining the house. The easiest way to explain how this tank works is by watching the following video:
We also have a third water storage tank behind our garage to capture runoff from the garage roof.
One of the key philosophies around how we harvest water is that every rainwater storage system includes an overflow system that feeds into another element on the property. This is different from most conventional systems where overflow is simply discarded. Here are some examples:
- The front rainwater harvesting system captures rainwater from the front of our house and the overflow feeds the food forest.
- The underground rainwater cistern is filled by the rear roofs of our house and the overflow feeds the back gardens.
- I traded a case of Budweiser with my neighbour to get access to his roof’s rainwater and got an additional 15,000L (~4,000 gallons) of water for my food forest that would have otherwise ended up in the storm drain!
Our rainwater storage systems allowed us to meet all of our outdoor water needs in a typical rainfall year without having to rely on grid-based water. As Bill Mollison once stated, “waste is just an unused resource.” As you can see from the 2015 property photo, the thriving food forest in the front yard speaks for itself.
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Food Forests: An Introduction
If you’ve never heard of a food forest, here’s the wikipedia definition:
Forest gardening is a low-maintenance sustainable plant-based food production and agroforestry system based on woodland ecosystems, incorporating fruit and nut trees, shrubs, herbs, vines, and perennial vegetables which have yields directly useful to humans.”
In our food forest we currently have plums, cherries, apples, seabuckthorn berries, currants, rhubarb, asparagus, goji berries, honey berries, Russian almond, raspberries, good king henry( a perennial salad green), sorrel, angelica, clover, alfalfa, rhodiola (a medicinal root) and much more.
We placed our community “fedge” at the front of the food forest. (A “fedge” being a fruit hedge). Ours consisted of Nanking and Romeo cherries and its mission was to tempt pedestrians into “stealing” fruit from our garden. It worked like a charm! These cherry bushes produce copious amounts of cherries and people cannot resist picking juicy red fruits when they see them. It was my subversive attempt to get people thinking about abandoning the traditional front lawn. I hope it worked on some level.
Next time, I’ll go more into depth on our other water systems design and share how we grow our greens through three seasons in Calgary’s harsh climate.
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