Mitigation requires an investment, and its cost must be estimated.  However, water companies should bear in mind that vulnerability reduction minimizes losses and the need for additional investments after a disaster.  Generally, the impact of such catastrophic emergencies sets back a water company’s development plans by several years, since operation and expansion budgets must be reallocated to rebuild what has been damaged or destroyed.

This does not mean that costly investments are always necessary for effective mitigation, at least in comparison with the price tag of rehabilitation and reconstruction. (Slide 19)

The costs associated with vulnerability reduction—as well as the risk management strategies to be followed—differ considerably depending on whether they apply to existing systems or those yet to be built (Slide 20).  In the case of existing systems, the difficulties in reaching and modifying, or replacing, some components (for instance, underground mains) make the work more expensive.  Systems still in the planning stage provide a unique opportunity to incorporate prevention measures into the original design, reducing costs without interfering with everyday operations.

This process of defining and implementing mitigation measures is greatly enriched when it is the result of interdisciplinary, interinstitutional efforts in which professionals and technicians contribute their knowledge and experience, making the entire group feel more motivated and committed to the success of the enterprise (Slide 21).

Vulnerability Assessment (Slide 22)

Risk maps

The impact of natural hazards on water and sanitation systems depends on the degree of exposure to the hazard, the technical characteristics of the component, and the structure of the system itself.  It is therefore essential first of all to identify which hazards threaten the system, particularly since its geographical extension often means that different components are exposed to different hazards. (Slide 23, Slide 24)

When hazards have been mapped and correlated with the location of the various components of the system, a risk map is obtained.  It shows which components are exposed to which hazards, and is a first step towards vulnerability assessment.

Geographical information systems are highly effective for producing risk maps, since they analyze the available information graphically, allowing for the zoning of hazards and identifying the components most exposed to them.

Vulnerability Assessment

Vulnerability is the likelihood that an element or set of elements will be damaged or destroyed by the occurrence of a disaster. When a pipeline is laid out on a riverside, or following the course of a highway, the system is more exposed to damage if the volume of water in the river increases (Slide 25, Slide 26) or the road is hit by, say, an earthquake.  To prevent this from happening, vulnerability must be assessed before such sites are chosen.

For instance, some professionals suggest that if the structure of a bridge is going to be taken advantage of to lay a pipeline, this should be done on the side of the bridge that is downriver, so that the bridge’s beams can protect the pipes in the event of a flash flood.

Once the hazards prevalent in the area have been identified, as well as their potential effects, vulnerability analysis makes it possible to identify the physical weaknesses of the system components.  Only by determining these weaknesses can corrective measures be taken (Slide 27).

Defining the criteria for reducing the risk to water and sanitation systems from natural disasters is the shared responsibility of water companies and the sector’s regulatory bodies or supervisory institutions.  When components are not properly sited, the infrastructure can collapse even in the absence of major disasters.

The vulnerabilities detected in the system may be identified either quantitatively or qualitatively so as to become aware of the situations of greater risk and assign priorities for meeting measures.  In the case of each vulnerable component, an estimate must be made regarding the level of damage it may sustain in the event of a disaster, from no damage at all to the total destruction of the component.  This analysis must be carried out for each specific event and each component of the system that is being assessed. (Slide 28.)

When carrying out the vulnerability assessment, it is necessary to identify the local and national agency in charge of disaster reduction, their procedures and methods, and the resources available to them. It is also important to characterize the area where the system component is located—distance from other towns, urban structure, public health situation, degree of socioeconomic development, services available, ways of access, etc.—and obtain a physical description of the system, including the most relevant information concerning each component and its operation, without leaving out seasonal data.

Slide 29 summarizes the links between the various risk management activities in water and sanitation systems.  It underscores that, in producing disaster and emergency response plans, it is vital to be aware of the prevailing hazards and the potential impact they might have on the system components and the level of service.  Vulnerability analysis requires that the following aspects be taken into account:

Administrative aspects and response capacity (Slide 30)

Next, operation and management standards and available resources must be identified, both in normal situations and in emergencies and disasters. The company’s response capacity is partly a function of its prevention, mitigation and preparedness measures, the way it has organized the operation and maintenance of its systems, and the administrative support it can rely on for such tasks.

In an emergency, it will be necessary to make decisions and carry out speedy actions that do not follow regular procedures, such as the issuing of public tenders for major equipment purchases or outsourced works. It is therefore important to develop special, streamlined administrative procedures that can be put into effect regardless of whether the emergency is decreed by the company itself or the local or national government.

Physical aspects and impact on the service (Slide 31)

Once the natural hazards threatening each system component have been identified, technical studies (vulnerability assessments) are carried out to estimate the damage each of them may undergo. Only then may the company estimate the level of service it could provide in the event of any given emergency.  This can be determined in terms of the system’s remaining supply capacity and the expected changes to the quality of the service.  It will also depend on the time required to restore services, whether partially or totally.

Mitigation and emergency measures (Slide 32)

Having characterized the prevailing hazards and the likely damage to the system, it is now possible to design and implement mitigation, preparedness and response measures.  Since systems that are invulnerable to damage in any form are financially and technically impossible, it is necessary to assign priorities to the mitigation measures to be implemented.

The results of the vulnerability assessment can have different uses, depending on the company’s resources and the criteria applied by management. Slide 33 shows various uses to which the findings can be put.  What is essential is that these assessments not remain mere academic exercises to be filed away and ignored by the company’s decision makers. 

Types of hazards and their consequences of water and sanitation systems (Slide 34)

The most frequent natural hazards in Latin America and the Caribbean are earthquakes, hurricanes, floods, landslides, volcanic eruptions and drought.  (Slide 35)  This slide is interactive; you can choose the types of hazard you would like to focus on.

In this section, each of these phenomena will be described, including the factors that turn them into natural disasters, how they affect water and sanitation systems, and some specific mitigation and prevention measures.

Earthquakes

Earthquakes may have various causes.  However, their destructive power will depend in part on the characteristics mentioned in Slide 36: