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State and trends


a large proportion of US water infrastructure is approaching, or has already reached, the end of its useful life. There are an estimated 240 000 water main breaks per year in the United States. The need to rebuild pipe networks is in addition to other water investment needs, such as replacement or upgrading of water treatment plants and storage tanks.


The US Environmental Protection Agency (US EPA 2013) estimates that approximately 4 000 to 5 000 miles of drinking water mains are replaced annually. The upgrade and maintenance of drinking water infrastructure in the United States requires investments of USD 384.2 billion over the next 20 years for thousands of miles of pipes, plus thousands of treatment plants, storage tanks, etc. Such investment is necessary to ensure the “public health, security, and economic well-being of our cities, towns, and communities.” About two-thirds of the need is for water distribution infrastructure. The rate at which water mains require replacement or rehabilitation depends on pipe material, pipe age, soil characteristics, weather conditions, and construction methods. Some pipe materials tend to degrade prematurely; galvanized pipe is particularly susceptible to corrosion in certain soils, and unlined cast iron pipe is susceptible to internal corrosion.


Assuming every pipe would need to be replaced, the cost over the coming decades could reach more than USD 1 trillion, according to the American Water Works Association (AWWA 2016). Delaying the investment will result in increasing water service disruptions, and increasing expenses for emergency repairs. The needs are greatest in five US regions: Far West, Great Lakes, Mid-Atlantic, Plains, and Southwest where capital spending has not kept pace with needs. Although funds are allocated through the federal Drinking Water State Revolving Fund, there is a trend toward state and local governments’ assuming most of the costs, since Congressional appropriations have declined (Copeland 2012).


The Canadian drinking water infrastructure was recently rated as over 70 per cent very good or good, with only 17 per cent fair, 9 per cent poor, and 3 per cent very poor


(Canadian Infrastructure Report Card 2016). Variations amongst municipal bodies that are often responsible for drinking water treatment also occur, with smaller, rural areas facing challenges with technical and managerial capacity (Hrudey 2008). In addition, rural communities also face challenges related to poorer quality raw water supply (e.g., draining agricultural land) that would pose challenges for even sophisticated treatment facilities (Petersen and Torchia 2008). Recognizing the complexities related to source water, treatment and water supply infrastructure, multi-jurisdictional groups, such as the Federal-Provincial- Territorial Committee on Drinking Water, have developed a series of guidance materials on the multi-barrier approach to safe drinking water for various audiences, including the public, and water industry specialists.


Dams and water storage reservoirs


With some notable exceptions, an era of dam construction in North America, beginning with the New Deal (1933–1938), largely ended in the 1970s. In many parts of the region, especially the interior West, communities depend on the water storage provided by reservoirs. Thousands of dams of varying sizes have been constructed around the region and have substantially altered the flow regimes of rivers and streams. In Canada, one of the world’s top dam builders, there are an estimated 933 large dams plus thousands of smaller ones; the bulk of large Canadian dams are used for hydro power (596), with other uses including multi-purpose (86 dams), tailings (82 dams), water supply (57 dams), and irrigation (51 dams) (Environment Canada 2010).


Reservoir storage, created by dams, is critical to the delivery of water resources to western communities in the late summer and early fall. The annual loss of storage capacity in US reservoirs (Figure 2.4.23) has been as high as 2 per cent per year in the west where rivers naturally carry large quantities of sediment, predicting a useful life of less than 50 years (Graf et al. 2010). Because reservoirs increase the surface area of water in a system, the evaporation from dams represents an important water loss to western areas. In the early 1960s, the USGS estimated that evaporation from reservoirs and


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