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State and trends


Case study Key messages: Freshwater


Most communities in North America, with some exceptions, are generally recognized as having safe and reliable access to water at an affordable cost.


• Legislation enacted in North America in the early 1970s has led to effective control of point sources of surface water pollution and ensure the delivery of safe drinking water to most communities in the region.


• While drinking water quality is in good condition in general, some drinking water infrastructure is aging and is in need of investment. Negative trends are chiefly the result of degraded infrastructure and weak governance. These isolated water quality incidents threaten human health, in some cases acutely.


• Water security in Canada and the US is generally quite high, due to the infrastructure and treatment available to mitigate the effects of variable water flows and pollution.


• However, the long-term sustainable supply of freshwater for irrigation, industry, and municipal uses is undermined by reliance on groundwater sources that are being depleted and contaminated, and the increasing threat of drought and water scarcity in arid regions.


• In some areas, legacy, persistent, and emerging freshwater contamination problems are perpetuated by historic and ongoing activities, including diffuse nutrient runoff and new industrial activity.


• Freshwater fisheries are well-regulated in the Great Lakes region and are generally controlled across North America, but face challenges due to factors such as climate change, population pressure, and pollution.


Box 2.4.1), although there are also increasing concerns about contamination of groundwater resources associated with the oil and gas industry. Non-point sources remain the largest source of pollutants, especially nutrients, to North American waters and contribute to the degradation of important coastal areas such as the Gulf of Mexico and the Chesapeake Bay.


2.4.2 Water quantity


The distribution of freshwater resources across North America is uneven. Generally, the West and far North are quite arid, experiencing more evapotranspiration than precipitation (Figures 2.4.1a and 2.4.1b). The coastal areas of the region are generally wetter, as is much of the eastern half of the region. The water issues faced in North America, therefore, also vary across the region.


Water use and withdrawals


Approximately 500 billion cubic meters of water are withdrawn from North America’s rivers, lakes, and groundwater every year (EC 2015d; Maupin et al. 2010). North Americans use more water per person than any other region in the world (UNEP 2012). However, North America has made some progress in water use as a result of increases in efficiency, conservation efforts and other sector-specific technological changes.


Total water withdrawals in the US declined by 13 per cent between 2005 and 2010, following a relatively stable period between 1985 and 2005, with the largest reductions in water used for thermoelectric power, irrigation, municipal supply and industry (Maupin et al. 2010; Figure 2.4.3). A similar pattern occurred over the same period in Canada with total


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