Flooded areas of land usually start off as very dry land. Floods are caused by heavy rains that pour to much water into rivers and other waterways. Making these natural channels unable to carry all the water. Rising water flows over or breaks the banks to the waterways causing the surrounding land to be flooded. Different causes of floods can come from masses of snow melting of tidal waves.
Where do floods occur?
The type of land that is prone to flooding are broad and flat usually situated on the banks of a river or main waterway. Rivers that flood are regarded in three different stages. They are:
تWater comes off the mountains, eroding the beds and banks of the river as it flows.
تThis type river travels through broad valleys which slows the current of the river down. If the current is slow it will transport less material down the river.
تFlood-plain stage. Little if not any erosion takes place most of the material tha tis carried in the current is suspended and deposited to the form a flood plain.
Primary effects تPhysical damage- Can range anywhere from bridges,cars, buildings, sewer systems, roadways, canals and any other type of structure.
تCasualties - People and livestock die due to drowning. It can also lead to epidemics and diseases.
Secondary effects تWater supplies- Contamination of water. Clean drinking water becomes scarce. تDiseases - Unhygienic conditions. Spread of water borne diseases. تCrops and food supplies - Shortage of food crops can be caused due to loss of entire harvest. However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil. تTrees - Non-tolerant species can die from suffocation.
Tertiary/long-term effects تEconomic - Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase etc.
