It is common to have floods during the monsoon season. However, when it rains heavily at any other time, there is always one main worry - flash floods! What causes them? Basically, it is a result of too much rainfall and land development. Normally, when it rains in a forested area, most of the rainfall seeps into the soil or is trapped by the plants. Some of it flows into the rivers and streams. So, flooding is less likely to occur as the soil acts as a sponge. However, with development, more concrete structures are constantly being built. When we build more roads and housing estates, the rainwater is prevented from seeping into the ground. In modern houses, the rainwater flows from the roof, into the gutter, and down concrete drains and into rivers. Usually this happens too quickly for the rivers to cope with the sudden rush of water. Besides, many of our rivers contain a lot of silt as a result of land development. This prevents the rivers from carrying away the water quickly, and flash floods occur. Many house owners in the towns and cities cement or tile their front yards. This stops the water seeping into the ground. The Drainage and Irrigation Department director general says , " Studies show that when we have development, the amount of water that reaches the river increases by 190 per cent. It also reaches the river faster." This means that in a city like Kuala Lumpur, millions of litres of water fill up the rivers which will in the end burst their banks and cause more damage. So, what is the solution? We can start by advising people to stop cementing their front yards. Housing developers should build ponds to collect rainwater. They can also build 'earth drains' instead of concrete ones to allow more rainwater to seep into the soil. If more than 100mm of rain falls in an hour, we are likely to experience a flood in some areas. If we are able to channel this water properly, fewer floods would occur.
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