When it’s a good thing to retain water
“I’m proud of you for not paving your driveway, Mark!” cousin Jim announced like I’d won a marathon. Jim has a strong environmental streak, as do his 22 cousins.
“Well that is permeable material: recycled asphalt,” I told him. My drive filters water on its way to the water table. Asphalt that otherwise would go to waste is sent to places like mine. Even asphalt can rise from its own ashes.
The idea of preserving rainwater is not a new one. Farmers on Canada’s Prairies perfected the use of rain barrels and cisterns during the 1930s drought of the Great Depression. Around the world, desert dwellers have developed very innovative methods of preserving rain water — many of them did it thousands of years before I laid my permeable driveway.
Today there is a new idea floating (pardon the pun) called Low Impact Development or LID, which is an approach that aims to “capture, slow or infiltrate stormwater close to where it falls.” It’s modern thinking about an old dilemma: what to do with excess stormwater.
The idea is to create urban designs using plants, permeable paving and other systems that mimic natural hydrologic systems. Ultimately the designers of LID reduce runoff that contributes to flooding and prevent pollutants from flowing into waterways. Five reasons to consider LID
1. Reduce risk The Insurance Bureau of Canada estimates that more than $1.7 billion dollars a year is spent repairing stormwater damage to property. LID may reduce the risk of flood damage due to stormwater overflow, and encourage some insurance rates to be reduced.
2. Plants help. Landscape plants play a valuable role in this plan. Their roots absorb enormous volumes of water over a year, transpiring the moisture through their foliage. As your landscape plants mature their ability to absorb and use excess moisture increases, as does the ability of the plant to sequester carbon, produce oxygen, and gener- ally cool the environment.
Create your own, if you have a yard, by simply digging a hole and planting the appropriate waterloving plants in it.
One of the temptations you have to resist is to water the plants in your bioswale during a drought. Properly selected, these plants will tolerate a period of drought and thrive during the long weeks of spring thaw.
In time, municipalities will likely require developers to employ LID methodology into their plans. Toronto already has green roof bylaws. Can LID rules be far behind?
In Kitchener/Waterloo, where summertime water restrictions are par for the course every year, property owners are now able to apply for credits of up to 45 per cent on the stormwater portion of their utility bills. These credits are for such measures as rain barrels, cisterns, infiltration galleries, rain gardens, and permeable pavers.
4. Manage your water. If you have an automatic, in-ground watering system, turn off the “automatic” feature and turn on your system manually only when your lawn and garden really need water. In the majority of cases, automatic applications of water are a huge waste of resources.
Responsible water management begins by letting your garden become dry to a depth of about three centimetres between waterings. Push your finger into the soil and make sure that it is dry up to your second knuckle before you turn on your sprinkler.
5. Change how you apply water. Consider installing a drip irrigation system for your vegetables and containers. Install rain barrels to collect free, warm and oxygen-charged rain water — your plants will love it. Apply water using a soaker hose; bury it under a couple of centimetres of finely ground pine or cedar bark mulch for greatest benefit. There is a porous hose made of recycled rubber and an alternative hose that is made of synthetic material that will last longer and take more hose pressure. Your choice.
And to Cousin Jim, a question: When are you going to get rid of your asphalt driveway? Just askin’. Mark Cullen is an expert gardener, author, broadcaster and garden editor of Reno & Decor magazine. Get his free monthly newsletter at markcullen.com. Watch him on CTV Canada AM every Wednesday at 8:45 a.m. Email him at groundskeeper@markcullen.com. Follow him on Twitter @MarkCullen4 and Facebook.