Flood

This Copernicus Sentinel-1 image combines two acquisitions over the same area of eastern Iraq, one from 14 November 2018 before heavy rains fell and one from 26 November 2018 after the storms. The image reveals the extent of flash flooding in red, near the town of Kut. Image: modified Copernicus Sentinel data (2018), processed by ESA, CC BY-SA 3.0 IGO.

Definition

Flood is usually used as a general term to describe the overflow of water from a stream channel into normally dry land in the floodplain (riverine flooding), higher-than–normal levels along the coast and in lakes or reservoirs (coastal flooding) as well as ponding of water at or near the point where the rain fell (flash floods) (IRDR Glossary).

Facts and figures

Floods are the natural hazard with the highest frequency and the widest geographical distribution worldwide. According to the Organization for Economic Cooperation and Development (OECD)  flooding is one of the most common, widespread and destructive natural perils, affecting approximately 250 million people worldwide and causing more than $40 billion in damage and losses on an annual basis (OECD).

Flooding occurs most commonly from heavy rainfall when natural watercourses lack the capacity to convey excess water. It can also result from other phenomena, particularly in coastal areas, by a storm surge associated with a tropical cyclone, a tsunami or a high tide. Dam failure, triggered by an earthquake, for instance, will lead to flooding of the downstream area, even in dry weather conditions.

Various climatic and non-climatic processes can result in different types of floods: riverine floods, flash floods, urban floods, glacial lake outburst floods and coastal floods.

Flood magnitude depends on precipitation intensity, volume, timing and phase, from the antecedent conditions of rivers and the drainage basins (frozen or not or saturated soil moisture or unsaturated) and status. Climatological parameters that are likely to be affected by climate change are precipitation, windstorms, storm surges and sea-level rise (UNDRR).

When floodwaters recede, affected areas are often blanketed in silt and mud. The water and landscape can be contaminated with hazardous materials such as sharp debris, pesticides, fuel, and untreated sewage. Potentially dangerous mold blooms can quickly overwhelm water-soaked structures. Residents of flooded areas can be left without power and clean drinking water, leading to outbreaks of deadly waterborne diseases like typhoid, hepatitis A, and cholera (UNDRR).

Related content on the Knowledge Portal

Data Source

Publishing institution: United Nations Office for Outer Space Affairs (UNOOSA)
The Space4Water Portal developed by UNOOSA present news, data and training information for all stakeholders involved in the space and water communities. It aims to provide access data and knowledge, to be creative and to realize their full potential in contributing to a world in which the availability and sustainable management of water and sanitation for all has become a reality. Launched in October 2018, the portal is building up available resources. It already presents training material related to flood mapping, and automating the production of global water maps using Sentinel-2 imagery.
Publishing institution: European Space Agency (ESA)
ESA's Earth Observation Thematic Exploitation Platform (TEP) is a browser for satellite imagery and specific products on an environmental topic. The TEP platforms are divided into 7 categories: Coastal; Forstry; Geohazards; Hydrology; Polar; Urban; and Food Security. Each platform is a collaborative, virtual work environment providing access to EO data and the tools, processors and Information and Communication Technology resources required to work with them. TEP aims to bridge the gap between the users and the data and tools.
Publishing institution: World Resources Institute (WRI)
The Global Flood Analyzer by the World Resources Institute is a tool to analyze flood risks. Parameter estimates for urban damage, affected GDP, affected population, annual expected urban damage and annual avoided urban damage for various three scenarios are visualized. Increased impact due to socio-economic change, climate change and future expected damages (2030) are compared against the base case of current annual expected damage. The scenarios are based upon the 5th Assessment report by the Intergovernmental Panel on Climate Change. For the current scenario, hydrological data from 1960 through 1999 for generating flood inundations for 9 return periods were used, from 2-year flood to 1000-year flood, and 2010 GDP, population, and land use data for assessing flood impacts. For future projections, 5 GCMs (Global Climate Models) from CMIP5 (Coupled Model Intercomparison Project Phase 5) projecting future flood inundations under two climate scenarios we used, RCP4.5 (...
Publishing institution: Airbus Defence & Space
Pleidas, TerraSar-X, SPOT and Elevation data available commercially from airbus, certain sample data sets at various locations available for free.

News

Image of the tailings dam flood on 30 January acquired by Operational Land Imager (OLI) on Landsat 8. Image: NASA.

The International Charter “Space and Major Disasters” has been activated for floods in Brazil following the collapse of a mining dam. The activation was requested by the Brazilian Disaster and Risk Management National Centre (CENAD). The country’s Ministry of Regional Development is acting as project manager for the activation.

A dam at an iron ore mine in the south-eastern town of Brumadinho collapsed, releasing a torrent of tailings. The large volume of sludge that spilled out of the dam then swept south west to Paraopeba River, burying the site’s cafeteria where workers were eating, as well as nearby homes and vehicles. The mud has reached a depth of 50 ft in some areas. According to media reports, 134 people were killed in the event, while another 199 are still missing.

... read more

Publishing date: 25/01/2019
Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured false-color images of the State of Rio Grande Du Sul  in 2007 Image: NASA

The International Charter “Space and Major Disasters” has been activated for floods in Brazil by the Brazilian Disaster and Risk Management National Centre (CENAD). The country’s Ministry of National Integration is acting as project manager for the activation.

Mudslides and floods triggered by sudden rain over the western area of the Brazilian state of Rio Grande do Sul have caused the Ibirapuita, Ibicui and Uruguai rivers to break their banks and cause widespread flooding.

The rains have swept away entire neighbourhoods in a mountainous tourist area near RioMetSul Meteorologia reported 497mm of rainfall in 72 hours in the state of Uruguaiana.

Over 2000 people have been displaced and moved to temporary accommodation as the floods damaged houses, blocked roads and water supplies were disrupted.

Local reports say the flooding peak in the city of Algrete was... read more

Publishing date: 14/01/2019

Event

La predicción y el monitoreo del agua y el clima extremo son una parte vital de la gestión de los recursos naturales de un área. En asociación con la UNESCO, ARSET está organizando una capacitación de seis días sobre aplicaciones de percepción remota por satélite para la gestión de cuencas hidrográficas.
Los asistentes aprenderán sobre técnicas de percepción remota aplicables a la gestión de recursos hídricos a través de estudios de casos y ejercicios.
Los temas incluirán:

  • Monitoreo y predicción de desastres relacionados con el agua.
  • Estimaciones de precipitación
  • Evapotranspiración de la humedad del suelo
  • Radar de apertura sintética (acceso y procesamiento de datos).
  • Clasificaciones de tierras

... read more

This RUS Webinar provides an introduction to mapping water body extent from a combination of SAR (Sentinel-1) and optical satellite data (Sentinel-2). It demonstrates how to access the RUS Service and how to download, process, analyse and visualize the free data acquired by the Copernicus satellites. The ESASNAP Sentinel-1... read more

UN-SPIDER Training Activity

UAV and Space Technology for Disaster Management | Date of training: 14/08/2018 to 16/08/2018

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