Human society depends crucially upon a series of infrastructure investments that have been made over centuries of time. We have constructed water, wastewater and power systems, as well as buildings, roads, ports, railways and other facilities. More recently, we have built complex telecommunication systems. In the process, humans have profoundly altered natural landscapes and ecological systems. The result has been a large number of inter-dependent infrastructure systems to support economic activity and social welfare. Without our infrastructure, society would not function in anything like its current state. We all have come to depend upon electricity from our power grid, goods delivered from our transportation systems, clean water from municipal water supplies and sewage services. In effect, infrastructure investment is a major social commitment, but it enables a great variety of economic and social activities.<\/p>\n
With our dependence upon infrastructure, it is not surprising that the management of our infrastructure is a critical economic and social task. Infrastructure wears out during use, deteriorates over time due to aging and weather effects, and can fail due to extreme stress from events such as earthquakes or floods. Maintaining, rehabilitating and renewing our infrastructure systems are a major undertaking for any society.<\/p>\n
Figure 1.1 – Example Infrastructure Facility: A Geothermal Power Facility in New Zealand. Source: Photo by Chris Hendrickson. Water is heated underground and the resulting steam is used in turbines to generate electricity.<\/p>\n
There is no widely accepted enumeration of the number and extent of infrastructure systems. Some analyses focus solely on publicly owned infrastructure, but this omits major systems in many countries, such as railroads in the United States. The American Society of Civil Engineers provides \u2018grades\u2019 of the condition of 16 different types of US infrastructure (ASCE, 2016), while the U.S. Department of Homeland Security\u2019s National Infrastructure Protection Plan identifies 18 types of infrastructure (DHS, 2016). The National Resource Council defines five \u2018critical infrastructure systems:\u2019 power, water, wastewater, telecommunications and transportation systems (NRC 2009).<\/p>\n
Defining the extent of infrastructure is difficult also due to the complexity of components within any type of infrastructure. For example, roadways have a variety of constituent infrastructure systems themselves, including:<\/p>\n