Early Safe
Timely alerts to safeguard lives and assets during disasters.
An effective Early Warning System (EWS) ensures that accurate, reliable, actionable, and understandable information reaches everyone who needs it in the right way and in time for them to take action to protect themselves and other people, their assets, and their livelihoods.
Introduction
Floods are the most common and widespread natural extreme weather event. When the water level surge submerges dry lands, it is termed a flood. Quickly or gradually the water level surges from a few inches to several feet. This can happen in various ways. Most common is when rivers or streams overflow beyond their banks, Excessive rain, a ruptured dam or levee, rapid and excessive ice melting in the mountains, or an overwhelmed river that can’t hold the water in its bank due to some beaver dam and spread its water over the adjacent land, which is called a floodplain.
According to reports from the World Meteorological Organization, approximately 70% of all disasters occurring in the world are related to hydro-meteorological events. Among these natural disasters, flood probably is one of the most catastrophic, affecting people across the globe.
Early warning systems for floods are an important component of natural disaster risk management strategies. The system uses data from sensors to measure water level surges in local water basins (rivers, lakes) or flood defenses (dikes, dams, embankments) to forecast alerts for a potential flood event. The early Warning System for floods evolved about 2 to 3 decades ago.
Back then it’s been understood that a system is required to generate and disseminate timely and meaningful warning information, to alert individuals, communities, and organizations that are going to be affected by floods, and to prepare and act appropriately in sufficient ways to save lives and resources.
Description
Early warning systems are an important component of disaster risk management strategies. In contrast to flood forecasting systems, which assess flood risk, the main purpose of early warning systems is to issue warnings when a flood is imminent or already occurring.
Early warning systems for floods comprise four interrelated elements:
- assessments and knowledge of flood risks in the area,
- local hazard monitoring (forecasts) and warning service,
- flood risk dissemination and communication service, and for community response capabilities.
This multifunctional system improves community preparedness for extreme weather events such as floods, in terms of both warning and increasing understanding of risks and appropriate flood responses. This minimizes safety and infrastructure threats. As part of the warning, the system provides a prediction of the scale, timing, location, and likely damages of the impending flood.
The system uses data from sensors to measure water levels at strategic points in local water basins (rivers, lakes) or flood defenses (dikes, dams, embankments) to forecast a potential flood event. The current increase in the number and degree of extreme weather events such as floods make this technology important for climate change adaptation.
Implementation Effective governance arrangements supported by political commitments should be established to maintain the early warning systems’ four elements. All stakeholders, including local communities, local and national government, international bodies, NGOs, the private sector and the scientific/technical community should be involved in the planning phase. Roles and responsibilities for system management and maintenance should be agreed upon, and necessary staff training should be completed prior to implementation.
Implementation of each element
Risk knowledge: Establish a system/agreement to collect and share data, figures, maps, etc. on flood risks and vulnerability in the area.
Monitoring and warning service: Establish sensors measuring water levels at relevant sites in local waterways and link them to the local database. The best available data and models should be chosen for forecasting systems.