Water Sector utility owners and operators have always had to respond to natural disasters. As a result, emergency response planning is inherent to the industry to ensure continuity of operations and to sustain public health and environmental protection. All-hazards preparedness is manifested in the sector’s vision, mission, and goals and aligns with the sector’s protection and resilience culture. Many utilities have conducted risk assessments and based on the findings of those assessments, owners and operators have created or updated emergency response plans (ERPs) and implemented numerous protective enhancements. These enhancements include: (1) improving control of access to utilities; (2) expanding physical barriers against vulnerabilities by installing equipment such as backflow prevention devices in pipes and locks on fire hydrants and manholes; (3) increasing control over access, delivery, and storage of chemicals; and (4) hardening cyber network control systems by installing virus detection software and firewalls, and in some cases by taking control systems offline.
Water Sector utilities have also increased their ability to respond to all hazards by: (1) planning for operator and customer protection against influenza pandemics; (2) establishing mutual aid and assistance through Water and Wastewater Agency Response Networks (WARNs); (3) participating in research and development (R&D) programs to improve protection capabilities; (4) improving outreach to the public health sector; (5) enhancing communications with both customers and consumers; and (6) organizing the Water Information Sharing and Analysis Center (Water ISAC) for effective communication for warnings and alerts.
Drinking Water – Drinking water is central to the life of an individual and of society; a drinking water contamination incident or the denial of drinking water services would have far-reaching public health, economic, environmental, and psychological impacts across the Nation. Other critical services such as fire protection, healthcare, and heating and cooling processes would also be disrupted by the interruption or cessation of drinking water service, resulting in significant consequences to the national or regional economies.
The Federal and State governments have long been active in addressing these risks and threats through regulations, technical assistance, research, and outreach programs. As a result, an extensive system of regulations governing maximum contaminant levels of ninety (90) contaminants, construction and operating standards (principally implemented by State regulatory agencies), monitoring, emergency response planning, training, research, and education have been developed to better protect the Nation’s drinking water supply and receiving waters.
There are approximately one hundred and fifty-three thousand (153,000) Public Water Systems (PWS’s) in the United States. These water systems are categorized according to the number of people they serve, source of water, and whether the same customers are served year-round or on an occasional basis. PWS’s provide water for human consumption through pipes or other constructed conveyances to at least fifteen (15) service connections, or serve an average of at least twenty-five (25) people for at least sixty (60) days a year.
Public water systems are defined in three ways: (1) Community Water System (CWS)—a PWS that serves people year-round in their residences; (2) Non-Transient Non-Community Water System (NTNCWS)—a PWS that is not a community water system and regularly serves at least twenty-five (25) of the same people over six (6) months of the year (e.g., schools, factories, office buildings, and hospitals which have their own water systems); and (3) Transient Non-Community Water System (TNCWS)—a PWS that is not a NTNCWS; these systems serve transient consumers. Transient consumers represent individuals who have the opportunity to consume water from a water system but who do not fit the definition of a residential or regular consumer; examples include gas stations or campgrounds where people do not remain for long periods of time. There are more than fifty-one thousand (51,000) CWSs, over eighteen- thousand (18,000) NTNCWSs, and approximately eighty-four thousand (84,000) TNCWSs in the United States.
Wastewater – Disruption of a wastewater treatment utility or service can cause loss of life, economic impacts, and severe public health and environmental impacts. If wastewater infrastructure were to be damaged, the lack of redundancy in the sector might cause denial of service. Regulations, research, and outreach, while extensive, have been aimed mostly at impacts to the environment and public health.
Wastewater is predominantly treated by publicly owned treatment works (POTWs), although there are a small number of private facilities such as industrial plants. The POTWs and privately owned wastewater treatment works that discharge treated effluent into the waters of the United States are subject to regulation under the Clean Water Act’s (CWA) National Pollutant Discharge Elimination System (NPDES) program. The administering NPDES body is referred to as the permitting authority. The permitting authority designates uses for all water bodies (e.g., fishing, swimming, and drinking), and then adopts water quality criteria that protect those uses. The permitting authority uses those criteria to set water quality standards for specific bodies of water; it then issues direct discharge permits that limit the concentrations of pollutants in the effluent based on the water quality criteria appropriate to the receiving water body.
There are more than sixteen thousand and five hundred (16,500) POTWs in the United States that collectively provide wastewater service and treatment to over two-hundred and twenty-seven (227) million people and are generally designed to treat domestic sewage. However, POTWs also receive wastewater from industrial (non-domestic) users; these industrial users discharge effluent into a collection system for subsequent treatment at a POTW and are subject to the national pretreatment program. Many States are authorized to administer this program, which ensures that effluent is compatible with the utility’s treatment capabilities or, if not, that the effluent is pretreated before being discharged to the collection system. Major and minor dischargers are defined according to a formula that considers the type of industry, flow rate, types of pollutants, and other factors.
Dams Sector assets include dam projects, hydropower generation facilities, navigation locks, levees, dikes, hurricane barriers, mine tailings and other industrial waste impoundments, and other similar water retention and water control facilities. The majority of the statistics provided in the following sections are based on data from the NID, which contains information on dams only. Although basic information on many sector assets is readily available through the NID, quantifying and characterizing other assets, such as levees, hurricane barriers, and mine tailings and other industrial waste impoundments, remain important challenges for the sector. Complete identification of the sector’s landscape will require significant interagency collaboration at the Federal, State, and local levels to leverage available resources and maximize collaboration with other programs.
The rapid growth of the American economy and population in the 20th century caused a corresponding increase in the demand for water infrastructure projects. Legislation such as the Reclamation Act of 1902; the Tennessee Valley Authority (TVA) Act of 1933; and the Flood Control Acts of 1928, 1936, and 1938 resulted in construction of a large number of dams and levees. Dam building in the United States peaked during the 30 years following World War II, when more than half of the Nation’s current total of 82,642 NID-listed dams was built.
Prior to the 1930s, levees were constructed haphazardly, without the benefit of good engineering practices, and generally to protect agricultural areas. Disastrous floods on the Mississippi and Ohio rivers spurred the U.S. Congress to pass the Flood Control Acts of 1928 and 1936, which established a direct Federal interest in the design and construction of levees. Although the total number is currently unknown, a recent estimate is that there may be as many as 100,000 miles of levees in the Nation. The aftermath of hurricanes Katrina and Rita turned the attention of Congress once more to levees and it passed the National Levee Safety Act of 2007.
Dams Sector assets are vital components of the Nation’s infrastructure and continuously provide a wide range of economic, environmental, and social benefits, including hydroelectric power, river navigation, water supply, wildlife habitat, waste management, flood risk reduction, and recreation, just to name a few. Some examples of the benefits derived from sector assets are discussed below:
Water Storage and Irrigation: Dams create reservoirs throughout the United States that supply water for a multitude of industrial, municipal, agricultural, and recreational uses. Ten percent of American cropland is irrigated by using water stored behind dams and thousands of jobs are tied to producing crops grown with irrigation water.
Electricity Generation: The United States is one of the largest producers of hydropower in the world, second only to Canada. Dams in the United States produce more than 270,000 gigawatt-hours, contributing 7 percent of the Nation’s electricity and representing 70 percent of the Nation’s renewable energy generation.
“Black Start” Capabilities: There are 4,316 megawatts of “incremental” hydropower available at sites with existing hydroelectric facilities. Incremental hydropower is defined as capacity additions or improved efficiency at existing hydro projects. During the August 2003 blackout in the Northeast, hydropower projects in New York and several other States were able to quickly start generating electricity, leading the way to restoring power to millions of Americans.
Recreation: Dams and other sector assets provide prime recreational facilities throughout the United States. In 2002, a total of 105.7 million recreation user-days and -nights were provided at hydropower projects licensed by the Federal Energy Regulatory Commission (FERC). In addition, about 400 million people annually visit a project of the U.S. Army Corps of Engineers (USACE), and about 90 million visit a project of the Bureau of Reclamation in a year.
Navigation: Navigational projects constitute an essential component of the U.S. waterway system, which includes 236 lock chambers at 192 lock sites owned and/or operated by USACE. A principal value of the inland and intracoastal navigation system is the ability to efficiently convey large volumes of bulk commodities moving long distances. If the cargo transported on the inland waterways each year had to be moved by another mode, it would take an additional 6.3 million rail cars or 25.2 million trucks to carry the load. The ability to move more cargo per shipment makes barge transport both fuel-efficient and environmentally advantageous.
Flood Risk Reduction: Many dams and levees function as flood control projects, thereby reducing the potential human health and economic impacts of flooding. Reservoirs and levees built by USACE reportedly prevented more than $19 billion in potential damages during the 1993 Midwest Flood. USACE levee systems currently provide a 6:1 return on flood damages prevented compared to initial costs and robust levee systems provide a 24:1 return on investments. Levees and hurricane barriers reduce flood damage to rural communities, as well as major metropolitan areas.
Sediment Control: Some dams enhance environmental protection by controlling detrimental sedimentation.
Impoundment of Mine Tailings and Industrial Waste Materials: More than 1,500 mine tailings and industrial waste impoundments controlled by dams in the Nation facilitate mining and processing of coal and other vital minerals and manufacturing while protecting the environment.
The benefits of these sector assets, however, are countered by the magnitude of the consequences that could be associated with their potential failure, damage, or disruption. The 42-foot-high embankment Laurel Run Dam near Johnstown, Pennsylvania, was overtopped and breached in 1977 after exceptionally heavy rain and serves as a modern reminder of the potential consequences of asset failure. Forty people died as a result of the failure and damages were estimated at $5.3 million. The potential for catastrophic consequences associated with extreme flooding and severe storm surges was evidenced in the aftermath of hurricanes Katrina and Rita in 2005, which resulted in the deaths of more than 1,800 people and economic damages estimated at more than $200 billion.
More recently, the 2008 Midwest flooding event affected significant urban and agricultural areas across a number of States, including Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, and Wisconsin, causing considerable property damage. Natural hazards such as severe regional floods can occur almost anywhere in the Nation and they clearly represent a significant factor in the complex risk picture of the Dams Sector. Extreme hydrological events can overwhelm the flood storage capacity of reservoirs and levee systems and raise the possibility of breaching or overtopping.
In another example, the near failure of the 142-foot-high Lower San Fernando Dam during a magnitude 6.7 earthquake forced the evacuation of more than 80,000 people in the San Fernando Valley of Southern California in 1971. This dam, which suffered severe seismic-induced damage, had been constructed with methods that did not provide adequate resistance to earthquake shaking. Analytical methods and seismic assessment procedures have greatly improved in recent years; however, it is still not possible to reliably predict the behavior of dams during strong ground shaking. A number of high-consequence assets are located in active seismic areas and their potential exposure to severe earthquakes constitutes a significant risk.
Droughts have the potential to affect hydropower production with the cascading impact of higher electricity costs as companies and power marketers must purchase power on the open market to meet customer needs. The 2007 drought affecting the Apalachicola-Chattahoochee-Flint river basin in the Southeast raised concerns about the capability of the basin’s hydroelectric facilities to continue functioning.
An assessment of the projected effects of drought on electric power generation in the Nation’s Western Electricity Coordinating Council system revealed that hydroelectric production could drop by almost 30 percent in a severe drought year; in typical years, approximately 28 percent of the system’s electric power capacity is supplied by hydropower, in wet hydrologic years it can rise to 40 percent. Additionally, electricity generated from coal would also drop as coal-fired plants would not have access to cooling water. Although natural gas plants could supply the electricity not supplied by hydropower or coal, the cost of electricity would increase.
These historical references provide a framework to highlight the importance of an all-hazards approach to risk management for the Dams Sector. The sector contains a number of high-consequence assets whose failure could cause sudden downstream flooding, resulting in a significant number of casualties and catastrophic economic impact. The consequences of a deliberate attack or serious natural disaster on any of these critical assets could be wide-ranging and depend on a number of variables, including the type of facility, the failure or disruption mode, critical functions (e.g., water supply, hydroelectric power generation, navigation, etc.), system redundancies, downstream population density, regional infrastructure, and seasonal conditions.
Given the many different assets within the Dams Sector, a number of failure modes and mission disruption scenarios could be theoretically within reach of determined aggressors with the necessary capabilities. This potential is a matter of special concern in the case of high-consequence facilities and constitutes an important element in the sector risk profile. The combined effects of growing downstream development, insufficient maintenance funding, continuous aging, inadequate past design practices, and exposure to potential extreme events caused by natural hazards or deliberate aggressor actions drive a complex risk picture that could affect millions of people located in the path of a sudden dam or levee failure.
The safety and security communities within the Dams Sector share the same interest of minimizing potential impacts resulting from failure or disruption. A coordinated approach to enhance the reliability, safety, security, and resilience of Dams Sector assets is required to address the entire spectrum of its risk profile through practical and cost-effective solutions.