The rapid changes caused by floods include washing away land. These are sometimes referred to as mudslides or landslides. The land washes away quickly, causing a change in the surface of the earth.
How do land use changes affect floods?
Owing to the spatial variability of flow processes, land use change effects on floods vary with the catchment scale. The impact of land use changes usually decreases with increasing catchment area for a finite size of the disturbance [ Blöschl et al, 2007] although the exact relationship depends on the local setting [ Bathurst et al, 2011 ].
Another frequent query is “How do floods change the landscape?”.
Floods will remove significant amounts of topsoil over a large area of farming land. While some parts of the landscape will lose significant amounts of topsoil (both from the flood but also from the sheet erosion as rain fell on wet soils) other areas will benefit from the depositing of new topsoil.
Floods occur naturally. They are part of the water cycle, and the environment is adapted to flooding. Wetlands along river banks, lakes, and estuaries absorb flood waters. Wetland vegetation, such as trees, grasses, and sedges, slow the speed of flood waters and more evenly distribute their energy.
What are the effects of floods?
However, floods have enormous destructive power. When a river overflows its banks or the sea moves inland, many structures are unable to withstand the force of the water. Bridges, houses, trees, and cars can be picked up and carried off. Floods erode soil, taking it from under a building’s foundation, causing the building to crack and tumble.
Land-cover change (urbanisation, deforestation, and cultivation) results in increased flood frequency and severity. Mechanisms include reduced infiltration capacity, lower soil porosity, loss of vegetation, and forest clearing, meaning lower evapotranspiration.
Heavy rain, a broken dam or levee, rapid icemelt in the mountains, or even a beaver dam in a vulnerable spot can overwhelm a river and send it spreading over nearby land. The land surrounding a river is called a flood plain. Coastal flooding, also called estuarine flooding, happens when a large storm or tsunami causes the sea to rush inland.
While writing we ran into the question “What are the causes of floods in cities?”.
Increased urbanization, for example, adds pavement and other impermeable surfaces, alters natural drainage systems, and often leads to more homes being built on floodplains. In cities, under-maintained infrastructure can lead to urban flooding.
What is a flood and how does it happen?
A flood is an overflow of water onto land that is normally dry. Floods can happen almost anywhere. They can cover an area with just a few inches of water or they can bring enough water to cover the roof of a house. Floods can be dangerous for communities, lasting days, weeks or sometimes even longer.