Conservation Corner: Go with the evidence


Conservation corner - summer 2005

The great fictional detective, Sherlock Holmes, once said something to this effect: “Avoid developing your theory before you collect the evidence. If you develop your theory first, you may interpret the evidence to support your flawed assumptions.”

I thought about this quote after talking to the person responsible for water conservation in a small town. The town was thinking about offering rebates on water-efficient washing machines. I asked a few questions and it quickly became apparent that money spent on rebates in this situation would have little to no effect on peak demand, which was caused by residential irrigation and agriculture. The theory was that water-efficient washing machines would reduce peak water use significantly, but the “evidence” (i.e. the data) suggested otherwise.

The more data you collect, the more refined a water conservation program can be. When Kelowna implemented its Water Smart program after universal metering in 1996, equal weight was placed on residential and ICI education programs. But data from the meters clearly showed that the peaks were caused by residential irrigation in four specific neighbourhoods. As a result, the ICI program was scaled back and more resources were put into programs targeting the four neighbourhoods.

In the absence of data, sometimes you have to make an educated guess. Salmon Arm implemented its Water Wise public education program in 2003. The city is not metered, so it was assumed that residential irrigation was the main problem. This was probably a good assumption, but a study done in 2004 showed that almost 54 percent of Salmon Arm’s water was unaccounted for. While Salmon Arm’s public education program is necessary and effective, the city is now looking at options to reduce system leakage and unbilled consumption.

Data can be misinterpreted and even ignored in large organizations full of highly paid brains. In her book, Pillars of Sand, Sandra Postel tells the story of a dam in Cape Town, South Africa. Spiraling population made it necessary to increase supply capacity by 40 percent. A dam was built despite a study that concluded the 40 percent increase could be achieved by reducing system loss—for a fraction of the cost of the dam. Of course, the dam silted up faster than the experts predicted, and the billion-dollar dam soon became a billion dollar boondoggle.

So Sherlock Holmes had it right all along. If you want to get the most out of your water conservation dollars, make sure they go to projects that create the greatest efficiencies. It’s elementary!


By Neal Klassen, BCWWA “Watermark” contributor


Posted January 2006

Originally published in the Fall 2005 issue of Watermark Magazine, the official publication of the British Columbia Water & Waste Association (BCWWA).

For more information contact Neal Klassen at