Flood

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).

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Related content on the Knowledge Portal

  •  Heavy rains in the Pacific Coast of Costa Rica have triggered floods and mudslides. 157 people in shelters.

    Source: glidenumber

  • An estimated 20,000 people in remote parts of East Sepik Province, northwestern Papua New Guinea, have been affected by floods - the worst in 40 years - along the Sepik River since late March

    Source: http://www.glidenumber.net/glide/public/search/details.jsp?glide=19111

  • Three villages have been engulfed by floods after the Kota Panjang hydro-power station (PLTA) was forced to release water to maintain the water level in the reservoir following high rainfall at upstream areas.

    Source: http://www.glidenumber.net/glide/public/search/details.jsp?glide=19106

  •  

    Flash floods triggered by days of heavy rain have killed at least four people, forced mass evacuations and cut off power to thousands in central Europe.

    Source: http://glidenumber.net/glide/public/search/details.jsp?glide=19104

  • Flash floods triggered by days of heavy rain have killed at least four people, forced mass evacuations and cut off power to thousands in central Europe.

    Source: http://glidenumber.net/glide/public/search/details.jsp?glide=19102

  • Flash floods triggered by days of heavy rain have killed at least four people, forced mass evacuations and cut off power to thousands in central Europe.

    Source: http://glidenumber.net/glide/public/search/details.jsp?glide=19103

  • Flash floods triggered by days of heavy rain have killed at least four people, forced mass evacuations and cut off power to thousands in central Europe.

    Source: http://glidenumber.net/glide/public/search/details.jsp?glide=19101

  • Source: http://glidenumber.net/glide/public/search/details.jsp?glide=19099

    Heavy ranfall received since 14th May 2010, and was continuing till date. Most of the areas in Colombo, Gampaha and Kalutara district has been affected by floods. Transport was difficult due to submerge of main roads and diffuclt to make emergency response. In additiona to that more than 80,000 families has been directly affected by floods. More over there has been only 1 death and few injusres has been reported. Since the data is still receiving the the actual figures may increase. Situation reports has been posted to DMC web site:

    www. dmc.gov.lk

     

  • On 4 January 2010, a massive landslide triggered nearly 1.5 KM wide blockage (referred to as the ‘Dam’) across Hunza River and Karakoram Highway (KKH) at Ataabad, 15 KMs east of Karimabad ( Hunza-Nagar district). Loss of life in Attabad was prevented through timely evacuations. However, humanitarian consequences of the disaster are:-
    · 20 died in an adjoining village of Sarat and 7 were injured;
    · 56 houses were destroyed in Ataabad and Surat and 60 were damaged;
    · 252 families are living in IDP camps in Karimabad, Hunza (142 families) and in Shishket (110 families), upper Hunza.
    Blockage of the Hunza River has created a Lake that extends nearly 15 kilometers into Gojal Tehsil of upper Hunza. The Lake has inundated a stretch of KKH including a bridge at Shishket. Village Ainabad and parts of village Shishkat are inundated and Gulmit is vulnerable. 110 families have been displaced and valuable agricultural land and fruit orchards are lost. 30,000 population in upper…

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  • Heavy rains caused flooding in 40 districts surrounding the Kur (Kura), Azerbaijan's main river. 20,000 homes have been flooded, 300 of them ruined, and 2,000 fell into disrepair. 50,000 hectares of cultivated land and pasture are under water.

    Source: GlideNumber

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