The 1931 China floods are the deadliest floods in recorded history. It is also called the Central China floods. They happened when major rivers like the Yangtze-Huai overflowed. Due to this disaster, approximately 140,000 people drowned and overall 2 million people died.
This example clearly shows us that overflowing rivers can cause extreme destruction. But there are also many other causes of floods you need to know. We wrote this article to tell you all the main causes of floods, including natural and man-made reasons.
Natural Causes of Flood
Natural causes of floods are events that happen in nature and lead to too much water in one area. These causes can increase water levels in rivers and nearby land. Below are major natural reasons behind floods.
Heavy Rainfall
Heavy rainfall is one of the main and meteorological causes of flooding. If a large amount of rain falls in a short time, the ground cannot absorb all the water. This extra water starts to collect on roads and low areas. Countries like China, Afghanistan and Mozambique recently have faced heavy rain-related floods.
Rivers and drains can also overflow because of too much water. As a result, water levels rise and may enter your homes, streets or your nearby areas. This situation mostly occurs after long periods of heavy rainfall. You must use a water-activated flood barrier (automatic flood barrier) during such conditions to reduce flood risk.
Overflowing Rivers
River overflow is the biggest and most common natural disaster that contributes to flooding. When too much rain falls in the river area, the river gets more water than its holding capacity. The water level increases quickly and goes over the river banks.
For example: South Asia regions like Bangladesh face most river overflow floods. During heavy rain and monsoon season, rivers rise quickly and overflow.
In this way, water spreads into your homes, fields, farms and nearby land. You can control large rivers with dams and levees that manage excess water. So, authorities make difficult decisions about when to release or hold back water in dams to reduce flooding.
Reservoirs, Rivers & Lakes With Slanted Sides
Lakes, reservoirs and rivers with slanted sides can also lead to flooding in some cases. For example: if the sides of these water bodies are not strong or stable, water can move out more easily. During heavy rain or fast water flow, the water level can rise quickly.
If the water cannot stay within its normal area, it obviously spreads into nearby land. Because, weak or slanted banks make it harder to control the water. This can result in floods in low areas.
Snow and Ice Melting
Most people who live near mountains face spring floods, which are caused by melting snow. During winter, snow builds up in cold areas and mountains. But if the weather becomes warm, you will see that the collected snow melts and creates powerful streams.
It rushes down the mountains and grows larger over time. This extra water also flows into rivers and lakes. If too much water enters at the same time, rivers can overflow and create flood risks.
Storm Surge and Tsunamis
Storm surges from hurricanes or tropical cyclones and tsunamis also lead to serious floods in coastal areas. The strong winds from a storm push sea water onto land which causes storms. This water can quickly flood your homes and beaches. You can use storm surge barriers to prevent these types of floods.
A tsunami is a huge ocean wave. Mostly, it forms after an earthquake or volcanic activity under the sea. When the wave reaches land, it carries a large amount of water and causes dangerous flooding.
Lack of Vegetation
If there are very few or no plants, grass and trees in an area, water flows freely and more quickly over the ground. It can increase the risk of floods. Plants and trees hold the soil and absorb rainwater.
If there is little vegetation, then the land becomes weak and cannot stop water. This fast water flow can fill rivers and drains very quickly. As a result, water spreads and contributes to dangerous floods.
Flooding Due To Climate Change
Climate change can also lead to a risk of more floods. It changes weather patterns and makes rainfall stronger and less predictable. As a result, you will see heavy rain in a short time instead of normal rain.
This sudden heavy rain can fill rivers, lakes or drains very fast. It also increases the water level quickly and causes flooding in various zones. Climate change can also melt ice faster, which adds more water to rivers.
Man-Made Causes of Flood
Man made causes of flood are the reasons that occurred because of human activities. These causes mostly make floods worse or trigger them in some areas.
Urbanization and Deforestation
If more people move to cities, you need to cut down trees to build houses and buildings. Both activities change natural land and reduce its ability to absorb rainwater. Then, the water flows quickly on the surface and collects in low areas easily.
This increases the risk of flooding in cities and towns such as West African coastal cities that face such issues.
Improper Agricultural Practices
Improper agricultural practices can also cause floods. If you farm in the wrong way, the soil becomes weak and cannot hold water properly. Further, overgrazing, poor irrigation or removal of natural plants make the land loose.
In case heavy rain falls, water runs quickly over this weak soil instead of absorption. This can increase water flow into rivers and drains, which lead to severe flooding.
Damaged Dams or Levees
Damaged dams or levees can cause serious floods. A clear example is Hurricane Katrina in 2005. Although the storm was very powerful, most of the flooding in New Orleans happened because the federally built levee system failed.
A dam or levee holds back water and also controls its flow. When it breaks or gets weak, they cannot stop the water properly. So, the stored water rushes out very fast and spreads into land
Poor Drainage Channels & Structures
Drainage channels and structures are systems that carry rainwater away. They include drains, pipes, canals and gutters. Their main job is to move extra water from streets and buildings to rivers or safe places.
They become poor or weak when they are blocked with garbage, built too small, broken or not cleaned properly. That’s why they cannot carry rainwater properly. This standing water can turn into flooding during heavy rain.
City Drainage Basins
Most cities are built with the use of concrete and waterproof materials. Because of this, rainwater cannot soak into the ground as there is no soil exposed. If drainage systems fill up, water starts to collect and can flood low-lying areas.
This problem is more common in large cities such as Houston & Los Angeles. During heavy rainfall, drainage systems commonly become overloaded, which leads to flooding in many regions.
Construction of Settlements in Flood Plains
Around the world, people build more homes & buildings in flood-prone areas. This increases the risk to people and property as climate change makes extreme weather more severe.
Flood plains are low areas near rivers where water naturally spreads during heavy rain. When you build cities in these areas, you put more people in danger. During heavy rainfall, rivers overflow and water easily enters these settlements.
Poor Garbage Disposal
Poor garbage disposal can also create floods. In fact people throw waste in streets & drains, it blocks the flow of water. Therefore, the water cannot move freely and starts to collect in one place.
During heavy rain, this blocked water quickly overflows and causes flooding. With clean surroundings and proper waste disposal, you can keep drainage systems clear and reduce flood risk.
How To Prevent Flooding?
You can prevent floods if you use simple safety methods to control water. Below are flood safety solutions you can use to reduce water damage during heavy rain and storms.
Flood prevention barriers: Flood barriers are strong walls or shields. They can stop water flow toward your homes and streets. You can place them around buildings or low areas. There are different types of these barriers including door flood barrier, inflatable flood barrier, flood panels / flood boards and basement flood barrier.
Flood prevention sandbags: Flood prevention sandbags are bags filled with sand. You can place them in front of doors, drains, basements, and weak points. They stop water from going inside and also protect homes during heavy rain.
Flood-proof Structures: Flood-proof structures are buildings designed to resist water damage. Common examples are buildings with elevated floors and raised roads. This approach keeps water out and reduces damage during floods.
FAQs
Are Floods Becoming More Common?
NASA and the IPCC report that extreme rainfall events have increased in many regions. At the same time, flood damage is increased because more people are living in risky areas. According to their research, the number of people living in flood-prone areas around the world has increased around 20% to 24% since 2000.
What Are the Effects of a Flood?
Floods can cause very serious damage. You will face the risk of drowning during a flood. They also destroy homes & roads. These disasters can spread diseases through dirty water and insects. Floods also damage farms, stop work plus force people to leave their homes.
What Are the Causes of Flash Floods?
Flash floods are sudden and very fast flows of water. You will face flash floods if there is heavy rain, quick snowmelt or when a structure breaks. They can start within six hours and rise in a very fast way.
Concluding Thoughts
Floods occurred due to many natural and human-made reasons like heavy rain, overflowing rivers, storms and poor drainage. You have to take proper flood safety actions. We also advise you to always keep an emergency flood kit ready with food, water and important documents if you live in flood-prone zones.
For strong protection, JACKWIN offers flood safety barriers, flood gates, flood doors and flip up flood barriers. We also provide a quick dam flood barrier alternative, so you can choose the best flood protection according to your situation. Contact us today!
