The myth of abundant Canadian water

The myth of abundant Canadian water

March 1, 2006

Canadians are always told by our politicians and media that we have abundant supplies of fresh water from our lakes and rivers. But the statistics do not bear this out. The true measure of water that we can use sustainably is the annual runoff from land. If we exceed that value, our water use is unsustainable. Canada has seven percent of the world’s land mass, and produces seven percent of the world’s terrestrial runoff. In other words, we have just an average supply of sustainable freshwater by global standards. Another common myth is that we have more water than the USA. Again, the numbers dispel the myth. The runoff per unit area in the two countries is almost identical.

One reason for the apparent abundance of our freshwaters is that we have abundant places for water to collect—in the depressions left by receding glaciers several thousand years ago. But having more basins to catch rain does not mean that more rain falls! Much of northern Canada, where freshwater is most abundant, receives less than 250 millimetres of precipitation per year. Many of the larger lakes would require 100 years or more to refill if we emptied them.

We also often forget how much of our water is in inconvenient places. Most Canadian rivers flow northward, away from the 300-kilometre-wide band along the U.S. border where most of Canada’s 30 million people reside, and where most of our demand for water occurs.

The western prairie provinces (Alberta, Saskatchewan and western Manitoba) are the driest part of southern Canada. In the rain shadow of the Rocky Mountains, some parts receive an average of less than 350 mm of precipitation per year, less than average evaporation. The only reason that agriculture and large cities like Calgary have been able to thrive is because their shortage of precipitation has been offset by rivers and aquifers draining from the Rocky Mountains, where higher precipitation and melting glaciers supply much of the water, especially in the dry summer months when water demand on the prairies is highest.

Both historical accounts and paleoecological studies reveal that these provinces have been plagued with droughts for centuries. In fact, the 20th century—when European immigrants arrived to begin instrumental measurements—appears to have been the wettest century of at least the past two millennia. Even the “dirty ’30s” suffered only a puny drought by long-term standards. Many droughts in earlier centuries lasted 20 years and more.

The probability that the 21st century will be as wet as the 20th seems very small. Furthermore, the effects of climate warming will aggravate the freshwater problem, if droughts occur. Already, parts of the western prairie provinces have had temperature increases of two to four degrees Celsius.

Another two to three degree increase is projected to occur by mid-century. Climate models also predict slight increases in precipitation. But the predicted increases would not be enough to counteract the increases in evaporation caused by increased temperatures. For the past 30 years, snowpacks have been getting smaller and melting earlier. The major glaciers of the eastern slopes have lost 25 to 37 percent of their mass in the past century. In nearby Glacier National Park in Montana, glaciers are predicted to disappear within 25 years. In short, glaciers and snowpacks will continue to dwindle, and they will not return.

It is perhaps ironic that Alberta, the province most vociferously opposed to controlling greenhouse gases in order to protect its pampered petrochemical industries, will almost certainly be the first to suffer from freshwater shortages. Some communities are already short of water. River flows in summer are only 40 to 70 percent of historical values. Seventy percent of irrigated agriculture in Canada takes place in Alberta. The province has the fastest population and industrial growth in Canada. There are only about 200 fish-bearing lakes in the province, and many of these are suffering already from poor water quality, the result of extensive land clearing, wetland destruction, growth of human and livestock populations, cottage development, and collapse of fisheries.

To a water expert, looking ahead is like the view from a locomotive, 10 seconds before the train wreck. Sometime in the coming century, the increasing human demand for water, the increasing scarcity of water due to climate warming, and one of the long droughts of past centuries will collide, and Albertans will learn first-hand what water scarcity is all about. Water scarcity will become one of the most important economic and environmental issues of the 21st century in the western prairie provinces.

But there is much that we can do to manage the problem. An average Canadian consumes about 326 litres of water per day at home, about twice the per-capita water use of Europeans, and many times that of people in Middle Eastern countries. Metering water and punishing high-water use with high cost would be a good start. The options already used in water-scarce parts of the USA could be copied—Xeriscaped lawns, low-water toilets, low-flow shower heads, reuse of gray water for lawns and gardens, and many other such practices.

Much of the water that we use for irrigation is used to grow hay and to feed livestock. For the past several years, livestock culture has not been sustainable. Most of the livestock is raised for export in any case. The best livestock operations only use about 20 percent of average water use, but so far there has been little incentive for farmers to adopt best water-management practices.

We could choose to raise crops and promote industries that use little water, or at least return it to our lakes in good condition following use. Bad management of the watersheds of lakes and rivers has exacerbated water-quality problems. Erosion allows silt, fertilizers, pesticides, and pathogens to be swept directly into watercourses. The draining of wetlands and the deforestation of the riparian zones that line the banks of streams further diminish natural protective mechanisms for aquatic ecosystems. Overuse and bad application procedures for manure and other fertilizers are also common. Perhaps it is time to provide incentives for landowners to retain or restore wetlands and streambank riparian areas. The costs would almost certainly be balanced by reduced costs of water treatment downstream.

We should also restore our commitment to the type of research and monitoring programs that allowed us to avert or reduce many freshwater problems in the 1960s and 1970s, which included the over-fertilization of lakes with nutrients and acid rain. As well, we need to make faster progress in international negotiations to reduce emissions of greenhouse gases and toxic contaminants. If we are to protect the freshwaters that are so important to Canadians, we must mount a comprehensive program of public education, research, monitoring, and enforcement. The current approach, which relies on recovery after problems have been caused, and which treats problems in isolation, is far too simplistic to compete with the multi-faceted attack on our freshwater systems by industrialized human society.

As a final step, it is time that we thought carefully about how many humans we want to crowd into Alberta. The population has increased by 50 percent since I arrived, and by over 40-fold in the last century. Industry is calling for more immigrants, but do residents of Alberta really want to become the Canadian equivalent of California? What will all the unskilled labourers do when the oil sands jobs are over? Will we be like Newfoundland after the demise of the cod? The time to make these decisions is now, not after our water is gone.

David Schindler is a Killam Memorial Chair and Professor of Ecology at the University of Alberta.

The views and ideas expressed in this column do not necessarily reflect those of the Canada Foundation for Innovation or its Board Directors and Members.