By Judie Steeves – Kelowna Capital News
Published: December 01, 2011 3:00 PM
Updated: December 01, 2011 3:54 PM
It’s the cutting edge way of dealing with storm water runoff, but at the same time it’s back to an earlier era.
Instead of designing for water to run off as quickly and directly over hard surfaces to the nearest gutter, storm drain and body of water as possible, the idea now is to slow it down, spread it out over the landscape and sink it into the ground so there’s far less to run off into drinking water sources.
“We need to re-visit the old ways,” comments Anna Warwick Sears, executive-director of the Okanagan Basin Water Board, “but based on engineering principles.”
The board has just completed a homeowner’s guide to dealing more sensibly with storm water runoff, called Slow it. Spread it. Sink it.
It describes a dozen ways you can use rain as a resource rather than getting rid of it from your property as quickly as possible.
“The more we can hold it on our landscapes, the more that’s available for groundwater, the cleaner our water is and the more there will be in streams for fish,” she commented, adding, “and it’s easy for homeowners to do.”
Basically, the concept is to distribute the load of water across the landscape instead of concentrating it on hard surfaces, where it can’t sink into the ground.
It’s particularly timely because one of the most-urgent impacts of climate change is flooding as a result of rain falling on snow, and of sudden downpours of heavy rain.
“We’ve mostly focussed here on drought impacts of climate change, but we can also expect more rain in winter and more variability,” noted Sears.
The trouble is, not only does runoff from storms cause erosion of the land, it also does harm to the nearest water body as soil and other materials are flushed off hillsides, parking lots and roadways and into our drinking water.
“So, if we don’t hold what falls on the land, we must up-size the infrastructure required to treat our drinking water,” she explained.
And, the more that can be held on the landscape, the more that’s available to recharge groundwater reserves and the cleaner the filtered water is when it eventually leaches into a body of water like Okanagan Lake.
Producing this publication was a great opportunity to piggyback on work in California, where they’ve been doing this because it saves money and for the environmental benefits, said Sears.
As we construct more impermeable surfaces in our cities, it becomes more vital to consider a different way of dealing with storm water runoff, she notes.
Planners, she said, should find this appealing because they’re being pushed up against the size limits for drainage pipes to accommodate flows from extreme storm events.
As well as improving storm water runoff, the concepts and techniques described in the booklet also link to water conservation and the livability of cities.
This 56-page guide is available online at the board’s website: www.obwb.ca and some hard copies will be made available this month to local governments and at the board office.