Chapter 4: Infrastructure impacts and adaptation challenges
2010; Wiley; Volume: 1196; Issue: 1 Linguagem: Inglês
10.1111/j.1749-6632.2009.05318.x
ISSN1749-6632
Autores Tópico(s)Disaster Management and Resilience
Resumo4.1 Adapting in an urban environment 4.2 Lessons learned from other metropolitan areas 4.3 Corporate and business climate change action planning 4.4 Conclusions and recommendations Creating an overall climate change adaptation strategy for urban infrastructure poses considerable conceptual and operational challenges. An understanding of the characteristics of a city's infrastructure that make it particularly vulnerable to the impacts of climate change is a critical foundation for understanding the severity of the impacts and the means for adaptation. Historical events that have compromised a city's infrastructure under conditions similar to those associated with climate change also provide information about what a city might expect in the way of consequences from a future of increased temperatures, precipitation, and sea level rise. This chapter explores the challenges to climate change adaptation in major urban infrastructure sectors with a focus on New York City, draws lessons from adaptation efforts under way in other large metropolitan regions, and discusses the role of the private sector in urban adaptation. The particular dimensions of infrastructure that are relevant to climate change primarily depend on location, exposure, and vulnerability, as well as the degree of protection against climatic forces. This section highlights some of the infrastructure most vulnerable to climate change in New York City as a means of illustrating the complexity of adapting in a dense, urban environment. As discussed in Chapter 3, New York City faces the following climate change hazards: Temperature: long-term changes in mean annual temperature and increases in the frequency, intensity, and duration of heat waves; Precipitation: long-term changes in mean annual precipitation and more frequent and intense precipitation events and drought; and Sea level rise and associated storm surge. New York City houses one of the densest infrastructures in the world. Because of its age and composition, some of this infrastructure and materials may not be able to withstand the projected strains and stresses from a changing climate. Rising temperatures may result in increased degradation of materials. Precipitation events of increased frequency, intensity, and duration may result in inland flooding that tests current drainage capacities. Rising sea levels may result in increased flooding that could degrade infrastructure materials from more frequent saltwater inundation and river flooding that can flood infrastructure not designed to withstand those conditions. Table 4.1 gives examples of infrastructure and assets that are likely to be affected by climate change. The provision of electricity can be roughly divided into production and distribution facilities, though many intermediate processes and facilities exist between these two services, such as transformers, area substations, switching stations, generators, and transmission towers. New York City is required to produce 80% of its electric power needs (in terms of forecasted peak events), though some pre-existing transmission systems providing external electricity that are dedicated to providing electricity for New York City can be included as part of the 80%.1 This condition presents a challenge to adaptation since on the one hand it promotes security and on the other hand it poses constraints on alternative ways of obtaining power from outside the city. Production facilities for electric power are concentrated in a relatively few locations relative to the customer base they serve. Presently, about two dozen power plants of varying sizes are operating in New York City (Fig. 4.1), and over a dozen more were proposed as of 2005. These facilities are owned and/or operated by a half-dozen entities. Traditionally power plants have required shoreline or close to shoreline locations for water intake structures and cooling water discharges; thus a number of the city's existing production facilities are located at lower elevations and potentially sensitive to flooding due to sea level rise. Locations of New York City power plants relative to 10-foot elevation contour.Sources: Compiled from power plant web sites and NOAA MESA NY Bight Atlas Monograph for historical records, K. Ascher, The Works (Penguin Press 2005), p. 98, and NYS DEC South Pier Improvement Project Gowanus Power Plan, April 3, 2008, http://www.dec.ny.gov/docs/permits_ej_operations_pdf/gpublic2.pdf. http://www.uspowergen.com/projects/south-pier/. Dots indicate very approximate locations of 22 existing power plants. The base map indicating 10 foot sea level contours is from V. Gornitz of GISS. Transmission lines that service the city are also relatively concentrated, entering the city from relatively few directions and providing little flexibility should any one of these lines be compromised. The lines enter New York City primarily from Westchester to the north and secondarily from Long Island to the east and New Jersey to the west. Thus, any given disruption in one of these locations will have relatively widespread impacts. The distribution system serving New York City, distinct from transmission, is one of the densest in the world, consisting of approximately 90,000 miles (145,000 kilometers) of underground distribution lines and 55 distribution networks within the city, each of which can operate independently of the other.2 Energy infrastructure poses a number of challenges to adaptation. Most infrastructure in the city relies on the city's power grid for energy, thus if it fails the other infrastructures that are dependent on it fail. The facilities that produce and distribute energy have traditionally been located in low-lying areas and are difficult and expensive to relocate. In addition, many power plants need to be located near the water to accommodate fuel deliveries, the use of water for cooling and steam generation, and water discharges, making relocation to areas not susceptible to flooding virtually impossible. These facilities are also concentrated in a relatively few locations within the city increasing the impacts of a climate hazard occurring at one location. The electric power industry is subject to a variety of regulations which presents a challenge to incorporating any new demands, such as climate change information, into its portfolio. Limited resources and multiple demands on those resources present another challenge to meeting energy needs. This situation is not only specific to New York City but is also common to the energy sector in general, occurring in many other urban areas as well. The transportation sector comprises the facilities and services to move people and materials over and through land, water, and air. It encompasses many modes of transport, including personal vehicles traveling on surface roads and public and private transport via bus, rail, ferries, and airplanes. Given the extent of use of rail transit within New York City, this section focuses on rail transit for passengers to illustrate the complexities and challenges that the transportation sector in general will encounter in adapting to climate change. The rail transit system serving New York City is the largest in the United States. Seven local and regional transit systems serve the city; however, the city has little jurisdictional control over these systems (see Fig. 4.2 for major rail lines). First, the Metropolitan Transportation Authority (MTA) manages three of the city's transit agencies: New York City Transit, Metro North and the Long Island Railroad. New York City Transit has 660 passenger miles of track (840 in total) and serves 1.5 billion passengers annually within the five boroughs (see Fig. 4.3 for station locations). Metro-North has 775 miles of track and services more than 80 million passengers annually running mainly to and from locations north of the city. The Long Island Railroad that runs to and from Long Island east of the city and has 594 miles of track and services 82 million passengers per year (MTA, 2008). Location and capacity constraints of New York City rail and subways.Source: City of New York, PlaNYC: A Greener, Greater NY, New York, NY: City of NY, April 2007, p. 96. http://www.nyc.gov/html/planyc2030/downloads/pdf/report_transportation.pdf. Location and condition of New York City subway stations.Source: City of New York, PlaNYC: A Greener, Greater NY, New York, NY: City of NY, April 2007, p. 93. http://www.nyc.gov/html/planyc2030/downloads/pdf/report_transportation.pdf. Second, the Port Authority of NY and NJ manages the Port Authority Trans Hudson system (PATH), which has 43 miles of track and services 66.9 million passengers per year between locations within relatively close proximity to the Hudson River (PANYNJ, 2008). Third, NJ Transit, a system managed by a different agency, runs further into New Jersey and enters New York City, has 643 miles of track and services 241.1 million passengers per year (NJ Transit, 2007). Fourth, Amtrak is also another provider of rail services, providing regional service through New York City. Other providers exist as well for freight transport via rail. Many of these systems share passengers and facilities that would require extensive coordination in the event of changes for adaptation. The sheer size and density of the city's transit sector, the fact that many of the facilities are located underground and/or either in coastal or river floodplains, the difficulty and considerable expense that would be incurred to retrofit or to relocate vulnerable portions of the system, and the need to keep the system operational are important considerations for climate change adaptation. The system has condition and capacity issues, which add to the climate change problem (Figs. 4.2 and 4.3). The transit sector and roadways have multiple owners and complex sharing arrangements that pose challenges to introducing adaptation. The city's rail systems are vulnerable to climate change by virtue of their low elevations which are susceptible to flooding from increased precipitation and sea level rise. Although many rail components in New York City are at low elevations, there is a dramatic variation in height above sea level. These locations are well known for the New York area, which will help in identifying particularly vulnerable areas (U.S. Army Corps of Engineers, 1995; and summarized in Jacob et al., 2001; Jacob et al., 2007; Zimmerman, 2003a; and Zimmerman and Cusker, 2001). For example, New York City Transit subway stations are as high as 91 feet,4 and as low as 180 feet below sea level in upper Manhattan. In addition to the stations themselves, the location and design of public entrances and exits, ventilation facilities, and manholes can play a role in determining vulnerability. Many stations are also very old, and the difficulty of relocating or elevating them to avoid flooding necessitates additional adaptation strategies. A recent incident of heavy precipitation of short duration gives an example of how extensive flooding of the rail system can be. Massive area-wide flooding from the August 8, 2007 storm discussed in Chapter 1 resulted in a near system-wide outage of the MTA subways during the morning rush hour. The event also required the removal of 16,000 pounds of debris from tracks and the repair or replacement of induction stop motors, track relays, resistors, track transformers, and electric switch motors.5 Such phenomena have periodically halted transit in New York City over the years (MTA, 2007) necessitating the use of large and numerous pumps throughout the system. Storms such as these lend themselves to analogies to flooding from climate change in the future (Rosenzweig et al., 2007). The flexibility of transit users to shift from one system to another is an important adaptation mechanism. An important factor influencing adaptation for rail transit facilities is the extent to which the configuration of transit networks consist of single extended rail lines that are not frequently interconnected with other lines, resulting in relatively little flexibility for shifting to another rail line if any one area of the line is disabled. Shifting to bus lines is often an option under such conditions. Portions of the New York City Transit and PATH systems are able to bypass bottlenecks depending on location, which was the case in both systems immediately following the September 11, 2001 attacks on the World Trade Center (Zimmerman and Simonoff, 2009). Challenges to climate change adaptation related to the water and waste sectors include aging infrastructure, a complicated regulatory environment, and lack of redundancy. The water supply sector comprises an interconnected system of natural water bodies and manmade structures, consisting of raw water sources (e.g., groundwater and surface water supplies) and facilities for water extraction (e.g., wells, where applicable, and pumps), storage, transmission, treatment, and distribution that bring water from sources to consumers. Water infrastructure components vary according to the type of water usage, such as the provision of potable water, wastewater transport and treatment, recreation, power generation, and supporting aquatic and terrestrial ecosystems. Used water that is not fully consumed is connected to wastewater systems. The nature of water supply infrastructure varies depending on the size, configuration, and nature of the sources and the distance water has to be conveyed. The New York City water supply system supplies about 1.1 billion gallons a day from a 1972 square mile watershed that extends to 125 miles from City Hall. The Catskill and Delaware watersheds provide 90% of this water, with the older Croton System supplying 10%.6 This flow to the city travels through an extensive network consisting of aqueducts, dams, reservoirs, and distribution lines along with pumping and other support facilities. To capture the supply, for example, there are four reservoirs and an aqueduct in the Delaware system; two impounding reservoirs, an aqueduct, and a tunnel in the Catskill System; and 12 reservoirs, the Jerome Park Reservoir, three controlled lakes, and an aqueduct in the Croton System (NYC MWFA, 2009, p. 46–47). Water from the impounding reservoirs in the Catskill and Delaware Systems flows to two balancing reservoirs, Kensico and Hillview. The construction of a treatment plant for the Croton System is under way in the Bronx. Within the city's water distribution system as shown in Figure 4.4 there are two water tunnels and over 6000 miles of water distribution pipe.7 The city is planning to introduce redundancy into its in-city water supply distribution system and also improve the ability for system maintenance through a variety of measures such as the construction of a 60 mile-long water tunnel, Water Tunnel No. 3, which is occurring in four stages.8 New York City water supply distribution system and third water tunnel planned locations.Source: City of New York, PlaNYC: A Greener, Greater NY, New York, NY: City of NY, April 2007, p. 69. http://www.nyc.gov/html/planyc2030/downloads/pdf/report_water_network.pdf. Wastewater treatment plants pose a challenge for adaptation, since they are characterized by older facilities located on the coastal estuary with limited ability to accommodate excess water, either from rising sea levels or intense precipitation. However, newer more decentralized ways of capturing and treating stormwater (NYC DEP, 2008) provide an important supplement for the stormwater wastewater component. These need careful coordination and integration into the city's system, and have multiple owners including private ownership. The wastewater collection and distribution system consists of "6600 miles of sewers, 130,000 catch basins, almost 100 pumping stations, and 14 water pollution control plants (WPCPs)."9 The wastewater treatment plants, by virtue of the way they are intended to operate with discharges to waterways, are primarily located along the city's shorelines, where the lowest elevations above sea level occur. During dry weather, the wastewater treatment plants are designed to fully treat one and a half times their design capacity and can partially treat about two times their design capacity. Where flows exceed that amount, for example, during wet weather conditions, water is discharged through the city's wastewater collection system—through combined sewer overflows (CSOs). CSOs and wastewater treatment plants are shown in Figure 4.5. Locations of Water Pollution Control Plants, CSO Outfalls, and Drainage Areas in the NYC area, 2008.Source: City of New York, PlaNYC: A Greener, Greater NY, New York, NY: City of NY, April 2007, p. 55. http://www.nyc.gov/html/planyc2030/downloads/pdf/report_water_quality.pdf. Waste collection is under the responsibility of numerous public and private entities in the City of New York, posing the challenges to the development of coordinated climate change adaptation plans. The New York City Department of Sanitation "recycled or disposed of 15,500 tons of waste per day (tpd) from curbside and containerized collections in FY2006."10 Most of the solid wastes that are not recycled are transported outside of the city for treatment and/or ultimate disposal rather than relying on disposal sites within the city. In the past, New York City has used in-city landfills for this purpose, but these have now been closed. Private sector entities play a large role in commercial waste management. Waste facilities sited in low-lying areas including closed landfills are also subject to flooding that could result in increased contamination of water bodies. If inundated by sea level rise, these facilities could create water quality problems, since many of them are located near shorelines and relied on closure technologies that did not take into account the current knowledge around climate changes. Solid waste facilities at risk include the marine transfer stations (shown in Fig. 4.6), garages and collection routes. As indicated in Table 4.1, marine transfer station operations can be interrupted and refuse along collection routes can be flooded during storm episodes. Long-Term Export Facilities and Watersheds. Location of solid waste marine transfer stations.Source: Modified from NYC Department of Sanitation, Comprehensive SWMP September 2006, Executive Summary, p. ES-17. http://www.nyc.gov/html/dsny/downloads/pdf/swmp/swmp/swmp-4oct/ex-summary.pdf. The widely dispersed nature of the city's infrastructure and the wide variety and extensiveness of networks and facilities is well illustrated by the communications sector. This sector is also heavily dependent on other sectors, particularly electric power as discussed in the section on interdependencies below, in order to function. The communications sector covers a wide range of services and facilities, including telecommunications, Internet service, and cable television. According to the Telecommunications Act of 1996, telecommunications, its equipment, and services are defined as follows: "(43) The term "telecommunications" means the transmission, between or among points specified by the user, of information of the user's choosing, without change in the form or content of the information as sent and received… (45) … The term "telecommunications equipment" means equipment, other than customer premises equipment, used by a carrier to provide telecommunications services, and includes software integral to such equipment (including upgrades). (46) … The term "telecommunications service" means the offering of telecommunications for a fee directly to the public, or to such classes of users as to be effectively available directly to the public, regardless of the facilities used."11 Communication systems encompass networks, such as fiber optic cable and copper wire, and include many different kinds of facilities for the intermediate and final receipt, transmission, and processing of signals (e.g., cell towers, satellites, computers, and phones). Each of these is potentially vulnerable to the impacts of climate change. The New York City communications infrastructure consists of a vast network of fixed structures to support communication and computing, consisting of voice lines, data circuits, fiber optic cable, switching stations, backbone structures, domain name servers, cell towers, satellites, computers, telephones (landlines), televisions, radios, and many more (Zimmerman, 2003b). Numerous communications providers serve New York City including AT&T, Verizon, T-Mobile, and many others. Communication equipment is vulnerable to climate impacts, for example, electrical support facilities such as relays, wiring, and switches associated with fiber optic cable can become flooded; cell towers can topple in strong winds and become corroded from unexpected exposure to seawater if sea level rises; and as seen in numerous disasters, an indirect impact is the dropping of calls due to saturated capacity from impacts that are more sudden. These vulnerabilities suggest relocating sensitive electrical equipment to avoid flooding and strengthening cell tower construction. Given the high degree of variability of the extent and ownership of the city's infrastructure, studies are needed to determine how such changes, variability, and differences affect any given climate change adaptation strategy. Sensitivity analysis is one method for accomplishing this evaluation. Sensitivity analysis is both a qualitative and quantitative technique to identify how results of an analysis change if the types and/or values of any variables change. For example, in the case of energy systems, such an analysis could identify how much electricity demand deficit would occur and hence how much backup power would be needed given an incremental change in electricity capacity due to excessive heat. Infrastructure designers, managers, and operators can use such analyses in considering climate change impacts and developing adaptation strategies. Sensitivity analysis is an important way of evaluating uncertainties. Uncertainties are associated with climatic conditions, impacts, and the success of adaptation. Impacts will not only change with variations in climatic conditions, but the estimates will also vary according to the degree of uncertainty in the climate risk factors. Therefore, even qualitatively performed sensitivity analyses are useful on scenarios or alternative conditions to determine the degree to which changes in the likelihood of climatic conditions will change impacts on infrastructure. All of the infrastructure sectors described above are dependent on and interdependent within one another in often complicated ways. Interdependency in the form of interconnectedness of infrastructure services is a critical factor in assessing climate change impacts and developing adaptation strategies, since they can magnify the consequences of a failure of a given type of infrastructure. Rinaldi, Peerenboom, and Kelly (2001) define infrastructure interdependency as, "a bidirectional relationship between two infrastructures through which the state of each infrastructure influences or is correlated to the state of the other. More generally, two infrastructures are interdependent when each is dependent on the other."12 A dependency in contrast would be a situation where one infrastructure depends on another, but the opposite is not true. Interdependencies and dependencies can be geographic or spatial (as created by spatially colocated infrastructure), or functional (including information technologies or cyber connections). In identifying these relationships, it is important to include all system components. Interdependence or interconnectivity occurs not only between infrastructures but within them as well. The importance of identifying these relationships is to enhance the ability to correct for cascading effects that might occur when one infrastructure failure inadvertently affects others. Numerous and often unspecified relationships among infrastructures exist that will make an outage in any one create an outage in another and vice versa. Examples for New York City are numerous given the complexity and density of the city. Transportation facilities depend on electric power to operate electric rail lines, traffic signals and lights for both road and rail transportation. Transit signals, electrified rail, and traffic lights shutdown when there is an electricity blackout. The subways and commuter rails and roadways have been temporarily disabled when a water main breaks in the vicinity of these facilities, and many of these episodes have been documented.13 The flooding resulting from water main breaks is analogous to what might be expected during flooding episodes brought about by increased storms and sea level rise associated with climate change. Train signaling systems and electric power plant and distribution controls that depend on telecommunications can and have failed when communication systems fail, and communications can fail in turn where the electric power, upon which they rely to function, fails. Electric power and emergency repair vehicles, in turn, rely on transportation for the delivery of goods and services. Water supply treatment or purification plants rely heavily on electric power and consume a large amount of water in their processes. A notable example in connection with climate change impacts is the increase in power needed by wastewater treatment plants in hot weather.14 Electric power facilities in turn are heavy users of water for cooling and steam generation. While electric power used to be the sector upon which most other sectors depended, communication information technologies are growing in their importance given the increasing dependency on these technologies for the command and control of infrastructure (Zimmerman and Restrepo, 2009). Power plants rely on communication equipment to monitor and control operations and coordinate activities over a vast network with multiple actors. Wired connections rely on wireless for backup. Wireless systems, however, rely on electricity to function, and wireless lines can become congested as traffic increases. Dedicated lines are one answer to the congestion problem, however, they are also vulnerable in emergencies. Communication and computer systems, in turn, rely on electric power to function. Examples within a given infrastructure sector include the reliance of power plants and power transmission and distribution networks upon one another. When one system or set of facilities is down, others can absorb or share the required load. For example, after the September 11, 2001 attacks on the World Trade Center which destroyed two substations, Con Edison was able to extend cables to substations in areas adjacent to the World Trade Center area to restore electricity at least on a temporary basis. There are management limitations to this adaptation strategy, however, since restrictions on electric power and operating permits, including emission limitations, are placed at the plant level. For electric power in New York City, these limits are set by the New York Independent System Operator (NYISO), Federal Energy Regulatory Commission (FERC), and the New York State Department of Environmental Conservation (NYS DEC). Similarly in the water sector, in times of drought, water sharing is common among water supply systems, or at least the facilities are in place to allow such sharing. During the drought of 1965, New York City put in a temporary pipe across the George Washington Bridge to share water with New Jersey. This is an example of geographic interdependency rather than functional interdependency. In order to develop adaptation strategies where interdependencies exist among infrastructures, the location and functional strength of these interdependencies have to be identified first. The scale of large urban regions presents unique challenges to climate change adaptation. Large-scale approaches have been suggested worldwide for cities of the size and density of New York City, largely surrounded by waterways. One example of an approach to developing citywide adaptation measures to enhance coastal flooding is storm surge barriers (Box 4.1). With regard to development of such citywide adaptation plans, it is important that cities consider adaptation approaches that are robust in several dimensions. The first dimension needs to be a thorough understanding of the risks that future coastal storms pose for any given urban area. Further dimensions are cost, timing, environmental impact, and feasibility. One possible long-term infrastructure adaptation measure for New York City would be barriers designed to protect against high water levels, which will increase in height as sea level rises (and possibly also through increasing intensity of storms). The risk of future casualties and damage from hurricanes and nor'easters might be reduced by barriers placed across vulnerable openings to the sea. Each barrier would require large open navigation channels for ships and a porous cross section allowing sufficient tidal exchange and river discharge from New York Harbor to maintain ship passage and water quality. At present, conceptual designs of storm surge barriers should be considered as contributions to the discussion on how to deal with the increasing risks of storm surge in New York City and the surrounding region in the era of climate change. A key point is that those risks still need to be better characterized in regard to the efficacy of citywide measures. Such options, which would entail significant economic, environmental, and social costs, would require very extensive study before being regarded as appropriate for implementation, especially as alternative robust approaches to adaptation are available. New York could protect against some levels of surge with a combin
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