GEOGRAPHY

Causes of floods

A flood happens when there’s too much water on land, usually after heavy rainfall. This causes rivers and dams to overflow. Sometimes, floods are also caused by human actions.

How Things to do with the environment help to cause floods

  • Long periods of heavy rain fill up rivers and dams

  • Steep slopes cause rain water to flow off the land quickly

  • If farms have destroyed vegetation or natural vegetation, water flows quickly into rivers off bare land

  • Tsunamis and storms can cause floods

How people help cause floods

  • People build dams, which can fill up the land

  • Farmers remove or burn natural vegetation to make fields, causing water to flow quickly off the bare ground

  • In cities water flows very quickly off streets and buildings

  • People remove or fill wetlands and lakes. These areas act as natural sponges, if they are destroyed they don't store water

Effects of a flood

Floods are natural events. People cannot stop floods from happening, but they can reduce the damage caused by floods.

The effects of floods on people and land

  • Floods can destroy crops and animals resulting in food shortages.

  • Floods can wash away soil making the land infertile and bad for farming. This is called soil erosion.

  • Floods can destroy buildings, property and transport systems.

  • Floods can wash sewage out of sewage works, polluting food and water supplies.

  • Diseases can spread easily after a flood.

  • Coastal flooding covers the land with salt water. The salt water kills plants and poisons the soil.

  • Serious flooding that destroys land and buildings may mean that some people will have nowhere to live. These people may have to move to another area.

Why some communities are at higher risk than others

  • They use river water for drinking, washing and cooking.

  • They need water to keep their soil fertile and make their crops grow.

  • The land next to rivers is flat and easy to build on.

  • There is not enough suitable land in other areas.

  • They do not have money to live in areas where there is no risk of floods.

  • They have ways of protecting themselves from the dangers of floods.

Reducing the impact-preparing for and responding to floods

Floods are natural events. People cannot stop floods from happening, but they can reduce the damage caused by floods.

Ways to reduce floods:

  • Building wlls and barriers along the banks of rivers and coast lines

  • build settlements away from rivers

  • Improve drainage in settlements so that water can flow away quickly

  • Make laws that prevent people from living in high-risk flood areas

  • Teach people about the dangers of flooding

  • Use lakes, natural vegetation and wetlands to prevent water from flowing too quickly into rivers

Population growth rates

Birth rate is the number of babies born per 1,000 people in a year, and death rate is the number of deaths per 1,000 people in a year. The population growth rate is found by subtracting the death rate from the birth rate.

Infant mortality

Infant mortality rate is the number of babies who die before age one, measured per 1,000 births. A table shows this rate for six countries.

 Factors affecting birth rates and death rates

  • Diseases

  • Economic status

  • Conflict and wars

  • Scientific developments

  • Improved healthcare

Disease

Diseases like malaria, HIV, TB, and cholera cause millions of deaths each year and can raise infant mortality rates. They also lower life expectancy. When many people in a region get sick, it’s called an epidemic. If the disease spreads across countries, it’s called a pandemic—like COVID-19 and HIV-AIDS.

 

Widespread illness

Hiv and Aids

Since 1981, around 50 million people have died from HIV. In 2023, about 40 million people were living with it, mostly in Africa. With antiretroviral (ARV) treatment, people with HIV can live a normal life.

Tuberculosis

Tuberculosis (TB) is a lung disease spread through droplets when an infected person coughs or sneezes. Breathing in these droplets can cause infection. Like HIV and AIDS, TB is one of the world’s deadliest diseases.

Some facts about TB:

  • In 2022 1.3 million people died from TB worldwide

  • In 2010 about 1.4 million people died from TB

  • Without proper treatment, two out of three people who have TB will die

  • About 900 put of every 100000 people in south afrixa are infected with TB

Malaria:

Malaria is caused by a parasite spread by certain mosquitoes. It enters the liver, then the blood, where it multiplies. Although malaria rates were falling, they are rising again. About 29% of the world’s population live in malaria hot spots, and most deaths are among children. Prevention includes mosquito nets, insect repellent, and medication. (called prophylaxis)



Diarrhoea:

About 2 000 children in Africa die every day from diarrhoea. Diarrhoea is a symptom of gastroenteritis, which can be caused by a viral or bacterial infection. Gastroenteritis causes the body to lose important liquids and minerals. If these liquids and minerals are not replaced, people can die.

Diarrhoea epidemics occur more often in poor areas where the water is not safe to drink and there are no proper toilets. Diarrhoea can be prevented by boiling all drinking water. It can be treated by giving the sick person a drink made from water, sugar and salt. Figure 4 on the right shows you how to make this drink.

Keywords:

  • Shock wave- a force of energy that shakes the ground

  • Fault- a crack or a weak point in Earths crust

  • Tsunami- a large wave of water caused by an earthquake in the oceans crust

  • Developing countries- countries where many people are poor and uneducated

  • Impact- force or strong effort

  • Cholera- a serious disease carried in water that causes diarrhoea and vomitting and may lead to death

  • Rubble- waste building material

  • Medical consultations- visits to a doctor

  • Food shortages- not having enough food to feed enought people

  • Coastal flooding- floods that affect areas next to the coast