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Compendium on methods and tools to evaluate impacts of, and vulnerability and adaptation to, climate change

Natural Disaster Mitigation in Drinking Water and Sewerage Systems: Guidelines for Vulnerability Analysis

These guidelines provide the basic tools to evaluate the vulnerability of a drinking and sewerage system to various natural hazards. These systems are vital to development, as well as to ensuring a return to normalcy following a disaster. Conducting this vulnerability analysis helps identify preparedness and mitigation measures to limit risks. It also identifies the response mechanisms that should be put into action in the event of a disaster.

The risk of damage to water systems increases with factors such as uncontrolled growth in urban areas, deficiencies in infrastructure, and climate change. The guide is divided into four sections:

  1. Planning;
  2. Principles of vulnerability analysis;
  3. Description of hazards and impacts;
  4. Conducting a vulnerability analysis for specific hazards.
Appropriate Use The tool is ideally used during the disaster preparedness phase to identify and implement mitigation measures. It is aimed at engineers and technical personnel of water service companies to project how the water systems will perform in the event of the disaster and to minimize damage. Vulnerability and probabilities of damage are expressed as various formulae.

The guide provides an overview for each section with issues to consider at each step. It also includes checklists (e.g. characteristics of an emergency operations center and the emergency committee; components of an emergency response plan), matrices to describe system vulnerabilities and extensive information on impacts on water systems from earthquakes, volcanoes, hurricanes, floods, etc.
Scope Water systems (with coverage being sub-national, municipal, etc.).
Key Output
  • Planning – Emergency committee established within the water company, with roles and responsibilities defined; emergency operations center established; partnerships with national organizations established.
  • Vulnerability analysis – Identification and quantification of deficiencies in the physical system and the organization’s capacity to provide services in a disaster; strengths of the physical system and the organization identified; recommendations for mitigating disaster impacts.
  • Mitigation and emergency response plans for administration/operational aspects – Identification of roles and responsibilities, resources required, and measures to reduce vulnerability. Measures may include: improvements in communication systems, provision of auxiliary generators, frequent line inspections, detection of slow landslides, repair of leaks and planning for emergency response.
  • Mitigation and emergency response plans for physical aspects – Identification of roles and responsibilities, resources required, and measures to reduce vulnerability. Measures may include: retrofitting, substitution, repair, placement of redundant equipment, improved access, etc.
Key Input
  • Planning – Information on: national standards, institutional coordination, and resources available for preparedness and response; and dialogue with partners.
  • Vulnerability analysis – Information on: organizational and legal aspects, availability of resources, hazards and likely impacts on the water system, current state of system and operating requirements, sensitivity of components to hazards, and the response capacity of the services.
  • Mtigation and emergency response plans – Information from the vulnerability analysis, priorities for implementing measures, and resources available.
Ease of Use Can be used as an overview for the emergency committee, although the vulnerability analysis should be conducted by a team of specialists.
Training Required Vulnerability analysis requires extensive experience in the design, operation, maintenance, and repair of a drinking water and sewerage system’s components.
Training Available The Virtual Campus of Public Health is a consortium of institutions led by PAHO/WHO for continuing education.
Computer Requirements Various specialized software, word processing, and spreadsheets.
Documentation PAHO. 1998. Natural Disaster Mitigation in Drinking Water and Sewerage Systems: Guidelines for Vulnerability Analysis. Washington, DC: Pan American Health Organization, Regional Office of the World Health Organization, htp://

Used throughout Latin America and the Caribbean. Case study in documentation from Limon, Costa Rica, to assess earthquake vulnerability.

Contacts for Framework, Documentation, Technical Assistance

Emergency Preparedness and Disaster

Relief Coordination Program, Pan American Health Organization, 525 Twenty-third Street, N.W., Washington, D.C. 20037, USA; Fax:+1.202.775.4578; e-mail: Contact lists for the Americas during a disaster:

Cost Free

Bibliography available in document