Disasters are the results of exposure to specific hazards (such as earthquakes, volcanoes, landslides, tropical storms, droughts, and floods), the conditions of vulnerability of human and/or natural systems to that hazard, and insufficient preemptive measures to reduce or cope with the potential negative consequences. A disaster may trigger countless impacts on the water sector at different timescales. Water-related disasters are expected to increase in both frequency and intensity due to climate change. It is, therefore, important to analyse strategies and policies for water-related disaster risk mitigation and adaptation. The most appropriate strategies should be formalised into a disaster risk management plan that details actions which aim to reduce risk, as well as actions and priorities to manage disasters once they have occurred.
Water-related risks arise from either too much water, too little water, or polluted water. Disasters can damage water supply and sewerage systems and thereby cause shortages and epidemic outbreaks of waterborne diseases like cholera. They can also cause the contamination of water (e.g. by acid rain after a volcano outbreak) or degrade water quality by reducing the dilution and dispersion of contaminants (e.g. during a drought). During floods or storms, water itself can damage properties and infrastructure. Floods and droughts are disasters that lie entirely within the direct realm of water management. In these cases, especially, water-related risks can be severely reduced through good water management.
Integrated water resources management requires all sectors that take precautions against disasters to consider the consequences to water resources, both in terms of the disaster itself (e.g. landslide) and the protection measures (e.g. building retention walls). Building infrastructure or changing a water course to protect against disasters can have upstream or downstream impacts, which should be taken into account in planning, and may require negotiation with impacted groups. Cooperation between sectors around risk management from water-related disasters can lead to much more cost-effective and successful solutions (e.g. urban design and agriculture leaving room for the river to flood).
Disaster risk management needs to be based on solid hydrological, social, and economic data, so the planning process starts with gathering that data. It needs to be integrated into the management plans prepared by the designated national disaster authority. The next step is to conduct a Risk Assessment (C2.01) for water-related disasters, identify the particularly vulnerable groups and systems (C2.02), and possible socio-economic impacts (C2.03). On the basis of these assessments, management options to reduce risk can be designed and evaluated, as well as priority actions in case of disaster identified.
The cycle of water-related disaster management usually occurs in eight steps: (1) mitigation; (2) planning; (3) monitoring and prediction; (4) disaster; (5) impact assessment; (6) response; (7) recovery; (8) reconstruction.
It should be noted that prevention strategies are generally less costly in social and economic terms than emergency responses, so they are essential for good management plans. Prevention strategies include no construction in flood-plains, planting drought resistant crops, and harvesting and storing water for drought periods. Other strategies for preventing landslides or flash floods include preserving vegetation, improving surface and subsurface drainage, reducing the slope, etc. Certain disasters can also have benefits. Floods, for example, deposit nutrient-rich sediments on river banks. For centuries, agricultural practices have relied heavily on them for the quality for their soil. In any case, disasters are impossible to avoid entirely, so procedures for the occurrence of disasters need to be addressed in disaster management plans as well.
Monitoring and multi-hazard early warning systems in communities at risk are an important step to increase disaster resilience and reduce potential loss of life. Governmental agencies should keep records of previous disasters and adequate hazard information about the risks should be available to the general public. This helps to increase awareness of the importance of preparing for disasters and passing the knowledge from generation to generation.
Afterthe occurrence of a disaster, a rapid multi-sectorial impact assessment is needed to strengthen coordinated response. This evaluation should be followed by a possible readjustment of previously established priorities for emergency response, and recovery actions to restore water services, which should be multi-sectorial and inclusive with clear coordination.
Recovery and reconstruction processes should focus on developing mitigation strategies to lessen the potential impacts of future disasters – to build back better. This can be done by mainstreaming preparedness into disaster management programs and by strengthening the resilience of communities at risk from water-related disasters via proactive measures to reduce their vulnerabilities to extreme events.
When it comes to developing disaster risk management plans, four general principles should be observed:
- Mitigation – prevention strategies are often less costly in social and economic terms than emergency responses, so they should be given priority.
- Enhance disaster risk governance – collaboration and partnership in activities engaging the whole cycle of water-related disasters.
- Invest in disaster resilience – develop structural and non-structural measures to promote economic, social, health and cultural resilience of communities. No-regret investments should be an integral part of national budgets.
- Strengthen preparedness – ensures capacities for anticipating and responding effectively. Evaluate locally available water resources and their roles in enhancing water related disaster resilience. Also, rehabilitation can be a good opportunity to “build back better”.
- Protection measures against water-related disasters should be multi-layered, connecting structural and non-structural measures. Aiming attention at preparedness, mitigation and adaptation strategies is less costly in environmental, social, and economic terms than focusing on emergency response on an event-by-event basis.
- Disaster risk reduction and adaption are two effective ways of reducing risks posed by natural hazards. A good risk reduction framework should include thorough participation by the poor, youth, children, elders, women, persons with disabilities, and indigenous peoples.
- Implementing integrated water resources management at all levels, including through transboundary cooperation as appropriate, is vital to strengthening resilience to water-related hazards.
- Proactive measures to reduce vulnerability of communities at risk from natural disaster are “low or no-regret” investments because they can yield benefits even in the absence of catastrophic events.
- Disasters can provide opportunities to highlight the importance of IWRM.