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FLOODING is worsening in urban areas due to more intensive downpours, primarily because of climate change.

As such, the authorities need to prepare to prevent or reduce this eventuality.

Most urban developments were built on lands that were converted into housing estates, commercial and industrial zones.

Thus, competent urban planning could have averted flooding in the new housing areas, as there was a large area to work on, unlike small pockets of land that have many constraints.

When earthworks are being done, proper planning needs to be undertaken to ensure road levels are raised, housing areas are on higher ground, and the all-important retention ponds are sited at a lower level to drain off the excess water swiftly as the rain intensifies.

Since most downpours occur in the evening, the retention pond water can be released in the morning and emptied. Retention ponds need to be well-maintained to ensure they can hold the run-off to their maximum capacity.

Urban planners can calculate the size of the retention pond required based on the developed or built-up area comprising houses, shops, factories, buildings, roads, public areas and others.

Retention ponds need to be regarded as essential. Otherwise, the roads, drains, as well as the housing and industrial areas, will be damaged, and the cost of repairing them will be significantly higher.

Rainwater harvesting on a large scale can reduce flooding, and the water can be used for alternative purposes by domestic and industrial users. Housing developers have not included rainwater collection tanks in their housing design, and the government needs to make it a condition for approving housing projects.

Industries can store rainwater in underground tanks as they have larger land areas. Domestic and industrial rainwater harvesting can save costs and should be regarded as essential to reduce dependence on piped water supply, which is facing much pressure from heat waves, freak weather, drought and climate change.

With present-day earth movers, a lot of levelling, filling, excavating, sloping, landscaping and designing can be done efficiently at low cost. Houses and roads should be built on higher ground to prevent floods.

Steep slopes can be made safer by reducing their incline or gradient, as maintaining and repairing steep slopes will prove costly to the local authority in the long run.

Main roads should not be constructed on steep elevations as they result in traffic congestion and heavier consumption of fuel for light and heavy vehicles.

The gradient should also be lowered on busier roads in housing and industrial areas.

Drains need to be well-maintained too to quicken the flow of water. Large storm drains need to be de-silted as sand and rubbish get trapped, reducing run-off capacity.

Nowadays, plastics of all kinds are the main garbage that flows into drains and rivers, causing blockage, damage and pollution. 

A lot of electric and electronic appliances are made of plastics that are difficult and costly to process by recyclers. Most of these are headed to the drains, leading to clogged drains, which worsen flooding or to landfills, which are filling up fast.

VT

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