What is Inland Flooding?
Homes can flood even when rivers do not overflow.
When people hear the word "flood," many may imagine a river overflowing.
However, in reality, there are disasters where residential areas flood even though rivers have not overflowed.
This is called **"inland flooding."**
Due to the influence of guerrilla rainstorms and linear precipitation zones, which have been increasing in recent years, the number of occurrences is rising, especially in urban areas.
💧 Why does inland flooding occur?
Inland flooding occurs when a large amount of rain falls in a short period, exceeding the processing capacity of sewers and rainwater drainage facilities.
Rainwater that should normally flow from roads and gutters into the sewer system cannot be drained, causing it to overflow onto roads and into residential areas.
In other words,
"a state where it rains too much and drainage cannot keep up"
This is the mechanism of inland flooding.
🌊 How is it different from river flooding?
It is often confused with "river flooding" (external flooding).
River flooding is a disaster where heavy rain causes river water levels to rise, overflowing or breaching levees and spilling water into the surrounding area.
On the other hand, with inland flooding, the river does not need to overflow.
Even if rivers are normal, if rain falls that exceeds the capacity of drainage facilities, urban areas and residential areas can flood.
Therefore,
🏞️ it can happen even if you are not near a river
is a major characteristic of inland flooding.
📍 What are the areas prone to occurrence?
Inland flooding is considered likely to occur in the following types of locations.
✅ Low-lying areas
✅ Areas where the land is lower than the surrounding terrain
✅ Residential areas with extensive paving that prevents rainwater from soaking into the ground
✅ Areas where sewer systems and rainwater drainage facilities have insufficient capacity
✅ Topography where water easily collects, such as valley bottoms or depressions
✅ Developed land that was originally wetlands or rice paddies
In urban areas, there is a lot of asphalt and concrete, which makes it difficult for rainwater to soak into the ground, so there are cases where roads become flooded even from short bursts of heavy rain.
🏠 What kind of impact does it have on homes?
With inland flooding, various types of damage can occur to homes even if the water depth is not very deep.
For example...
💦 Flooding under the floor or above the floor
🚗 Flooding of parking lots and garages
⚡ Failure of equipment such as water heaters and air conditioner outdoor units
🚪 Water entering basements or underground parking lots
🚧 Road closures due to flooding
🦠 Mud and sewage may flow in, requiring cleaning and disinfection.
Even if you think it is just a little bit of water pooling, it can take a lot of time and money to restore.
🔍 Points to check when choosing land
When purchasing a home or choosing land, it is important to check not only the building but also the surrounding environment.
✔ Check your local government's inland flood hazard map.
✔ Compare it with the flood hazard map.
✔ Check if there are any areas prone to flooding on surrounding roads.
✔ See if the property is lower than the surrounding area.
✔ Check past flooding history with the local government or neighbors.
It is important not to assume that you are safe just because there is no river nearby, but rather to check the drainage capacity and topography as well.
✨ Summary
Inland flooding is
**"a flooding disaster that can occur even if rivers do not overflow."**
In recent years, as short-duration heavy rainfall has increased, it can occur not only in urban areas but all across the country.
When choosing land,
🏡 "looking at the flood hazard map" is not enough.
By checking inland flood hazard maps, land elevation differences, and surrounding drainage conditions, you can more accurately grasp future flood risks.
When choosing a home, considering not just the building but also **"the safety of the land" is the first step toward a home where you can live with peace of mind.**