Flood Impacts

Which dimensions do floods positively impact?

• Environmental

• Economic

How do floods impact the environment positively?

• Replenish groundwater reserves

• Stimulate essential life processes (bird breeding, migration & seed dispersal)

• Flush pollutants and pathogens from domestic areas

How do floods impact the economy positively?

Flood patterns can impact livelihoods of people

Example of how floods positively impact the economy

Lower Mekong Basin; Flood benefits are estimated to be US$8-10 billion.

• Mekong Delta; floods deposit 150 million tonnes of fertile sediment on paddy fields annually, leading to robust yields for rice farmers

• Mekong fishery: capitalises on annual fish migrations during flood season.

• Floodwaters carry nutrient rich sediments supporting plant and animal life in wetlands.

What dimensions do fluvial floods negatively impact?

• Social

• Economic

• Environmental

What are some losses that floods can cause (direct & indirect)?

Direct Losses:

• Loss of life, crops and damage to property & land

  • Results in: Requires funds to rebuild and causes loss in market value of property.

Indirect Losses:

• Reduced tourist spending, spending power of community and increased vulnerability of survivors.

  • Results in: Out-migration & reduced confidence in the area.

Examples of negative impacts of floods on social dimension [prior to flood/during floods]

UN Office for Disaster Risk Reduction; Between 1995 & 2015, floods affected 2.3 billion people, accounting for 56% of all those affected by weather related disasters.

Countries of lower levels of development are not well equipped to cope with floods due to lack of equipment, warning systems & expertise, causing greater loss of lives.

Pakistan, 2010; 2100 people were killed due to floods, and approximately. 6500 people died due to floods in the country.

Cambodia, 2000; Over 300,000 families were affected by floods in September 2000.

Example of how floods negative impact social dimension [after flood]

• Overcrowding in relief shelters — overcrowded camps, schools & other public buildings’ lack of sanitation and basic services.

• Exposure to waterborne diseases (cholera and dysentery) —- caused by contamination of sewage and dead bodies.

• Food shortages; damage to crops and livestock

  • 2015 Malawi flood; washed away food stocks and ruined fertile land, causing the worst food crisis the country has faced in 10 years, of which an approx. of 2.8 million faced hunger.

What are some negative economic impacts floods have?

Has the ability to cripple the national economy, especially for countries dependent on agriculture.

Irreparable damage to properties due to its powerful force and ability to infiltrate through cracks

• Weakens buildings structurally —- render them inhabitable; results in rebuilding efforts.

Example of how floods causing negative economic impacts.

August 2018, Kerala India; Government of Kerala worked with World Bank & Asian Development Bank to conduct a joint Rapid Disaster Needs Assessment to quantify the extent of damage caused by the floods; amounted to an estimate of US$3.5 billion for recovery of priority sectors alone.

What are some negative environmental impacts of floods?

Floodwaters can carry sewage and hazardous chemicals from factories, posing risks to the environment.

Examples of negative environmental impact of floods

2010 Indus Basin flood; Severe floods triggered by intense monsoon rains that led to rapid river overflow and widespread inundation. Around 30% of Pakistan was submerged, with over 11,000 villages flooded and about 7 million hectares of fertile land destroyed. Loss of crops and livestock caused severe environmental and economic disruption, especially in key areas like Punjab, contributing to food shortages and rising prices.

Variations in Effects Of Fluvial Floods

• Vary from place to place

• Vary depending on different groups of people

Types of Variations from place to place

• Magnitude of flood — higher volume of water and higher velocities create more destruction

• Intensity of urban/agricultural development — areas more intensely developed experience greater economic/social losses.

• Effectiveness of flood management strategies — well designed infrastructure help reduce flooding and protect vulnerable areas.

• Capacity to recover from flood induced damage — essential to long term resilience of community and ecosystems

Variation in effects of floods experienced by diff groups of people; environmental dimension contributing to vulnerability

Poor rural areas are inaccessible and distant from the scrutiny of governments and aid monitoring; make them more vulnerable to disasters; e.g. remote mountain villages in the Himalayas/Andes.

Variation in effects of floods experienced by diff groups of people; social dimension contributing to vulnerability

Age & gender; the young and elderly are more at risk

• Bangladesh Cyclone disaster, 1970s; more than half of all deaths were children under 10 years old, despite making up only 1/3 of total population. Survivors over 60 years old and females are more likely to suffer from serious physical injuries and psychiatric stress disorders.

Variation in effects of floods experienced by diff groups of people; economic dimension contributing to vulnerability

Those without money, land, tools or help from family are most at risk; impact can be severe as people struggle to maintain their livelihoods after the disaster.

Social and economic factors exacerbate risk from environmental hazards;

• Flash floods Southern Nepal in July 1993; Over 1600 people were killed, where fatalities were concentrated in vulnerable groups like children, females, and those with lower socioeconomic statuses. Those living in thatched houses were also over 5 times more likely to die rather than those living in cement/brick homes as they were less likely to be washed away.