Steps can be taken to manage the flood.
This is the so-called river management.
Typically, these steps include an attempt to extend the time required for the water to reach the river course, thereby increasing the lag time.
Hard engineering methods tend to be more costly and have a greater impact on rivers and surrounding landscapes.
In order to stop the flood, they will need to carry out a wider transformation of the river.
Soft engineering methods are usually sensitive to the ecological environment.
Instead of stopping the flood, they will try to manage it.
Hard engineering method
Engineering dams built along the river to control emissions.
The water is blocked by the dam and released in a controlled manner.
Water is usually stored in a reservoir behind the dam.
The water can then be used for power generation or entertainment.
It's expensive to build.
When the valley is flooded to form a reservoir, settlements and farmland may be lost.
The flood wall is used to raise the height of the river bank to a level where the river does not break its banks.
It can be a permanent feature or can be incorporated into the design of an area and become invisible.
It can also be temporary construction where flood control gates or movable "shantytowns" are built to protect a river.
Dams and artificial dams can be built along the river bank so that if the river floods, the water cannot break through the walls and cause damage.
The flood-proof embankment can be expensive and will spoil the appearance of the river.
Flood control dams are usually used in rural areas.
They can take up a lot of space and are cheaper than flood-proof walls, but they can also cause an increase in the speed of water in the river, which will only push any potential flooding further downstream.
The river course may be widened or deepened so that it can carry more water.
The river can be pulled straight so that the water can go faster along the river.
The rivers of the river can also be changed, shifting flooding from settlements to other places.
Changing the course of the river can lead to a greater risk of downstream flooding, as the water there carries faster.