The latest monsoon rain-induced floods have killed almost a dozen people across Johor, Pahang, Kelantan, Terengganu and Perak. In addition, it is set to dispossess taxpayers of millions in aid, recovery and rebuilding costs.
And to a large extent, we only have ourselves to blame. Our careless, reckless plundering of mother earth’s finite resources is making floods – and many other extreme weather events – more prevalent and deadly.
But just as we have had a hand in exacerbating floods, we can also do things that will attenuate and eventually eradicate them. They include:
Reforestation around low-lying, flood-prone areas
According to the Geographical Association, Malaysia suffers the ignominy of having the highest deforestation rate of any country in the world.
From 2000 to 2012, Malaysia’s rate of forest loss was at 14.4%, beating out even Brazil and Indonesia. This amounts to 19,200 square kilometres – an area almost the size of Perak and more than double that of Selangor.
What many don’t realise or choose not to is that the forest is our protector when it comes to flooding. It provides dense vegetative cover that promotes evaporation, an abundance of roots that soak up the water to nourish themselves and soil that allows water to slowly seep through it, forming groundwater. In addition, foliage and forest cover slow down water flow, ensuring it doesn’t pick up the kinetic energy needed to do serious damage downstream.
However, our practice of rampant, indiscriminate logging and clearing of vegetation destroys the soil’s capacity for water retention and reduces its porosity. This wanton removal of nature’s millenia-old, built-in safety mechanism is leaving us vulnerable to the floods we’re seeing today.
The president of Pelindung Khazanah Alam (PEKA), Shariffa Sabrina Syed Akil says, “It (floods) is not due to rain or weather factors. Big floods will not happen if we have enough forests to act as a ‘sponge’ to control the flow of rainwater. What is happening now is that the forests are being cleared, causing rainwater to flow along with the sludge and logging waste.”
She’s right on the money. To counter this, we need to institute laws that carry a strict penalty for logging or clearing vegetation, in addition to mandating reforestation around low-lying, flood-prone areas.
Keeping drains and rivers clear of pollution
Monsoon rain-induced floods occur when water buildup exceeds rivers’ carrying capacities, resulting in them overflowing into and inundating the surrounding areas. There are two ways we can increase the carrying capacity of rivers and drains: (1) clearing solid pollutants that are clogging them or impeding their flow, and (2) making them larger – either widening them, deepening them or both.
The lowest hanging fruit is the first option – ensuring polluters are heavily fined and pollutants are immediately cleared so there aren’t any impediments to water flow in drains and rivers. Simple, custom-designed surveillance Internet of Things (IoT) modules could come in handy here.
These IoT modules can be installed at designated spots along the river to monitor the area. They can consist of a pollution detection sensor, a camera, a micro-controller, a transmitter and a rechargeable lithium ion battery – all solar-powered – making them a powerful, yet relatively cost-effective way of keeping polluters at bay.
In addition, regular maintenance crews should be dispatched to areas that are prone to clogging. This will avoid the kinds of complications that we saw happen in Sungai Skudai during this flood season. Residents in the area had seen the water level in the river rise precipitously and had alerted the city council and the Drainage and Irrigation Department (DID) about the clogged drains that were causing it. However, the cleanup work was unsuccessful, resulting in the area being flooded.
Creating floodplains and swales
Areas next to rivers that are prone to overflowing can be converted into floodplains. When these rivers overflow, the excess water can flow into these large floodplains and increase the area’s water carrying capacity.
The size of the floodplain needs to be made commensurate with the severity of the flood that occurs in the area. This floodplain then can become a sacrificial piece of land that floods during monsoon seasons, protecting inhabited areas.
During non-monsoon seasons, this floodplain could double as water-dense, fertile, agricultural land on which villagers can grow an array of vegetables. However, to protect the lives of the inhabitants in the area, residents will not be allowed to build houses in the floodplain and those who are already there will have to be relocated.
In cities however, parks and green lungs could serve this role. They could be constructed strategically in low-lying areas so that when a flooding event occurs, water would flow into these parks, flooding them and turning them into temporary floodplains.
In addition, swales could be constructed along major highways, roads and housing areas that are prone to flooding. Swales are merely sloping, shallow, grassy canal-like features on the sides of roads that allow water to penetrate the land, recharging the earth’s groundwater and reducing surface runoff. This ensures water doesn’t collect on land and reduces the likelihood of flooding events.
Permeable pavements and surfaces
Even though the latest flood-induced carnage has predominantly affected rural areas, our cities are the most susceptible to flash floods. One of the worst in recent memory was, of course, the flash flood that occurred around the Masjid Jamek area in September 2020, damaging hundreds of cars, bringing traffic to a standstill and handing the city and its dwellers a massive cleanup bill.
Underground drainage systems are designed to mitigate this but they often fail, due to clogging, inadequate capacity or both. This is further exacerbated by the mostly impermeable surfaces populating today’s concrete jungles. Today’s cities only allow around 15% of water to seep through them, while natural ground cover allows more than triple this, at around 50%. This is where permeable surfaces can be a game-changer.
Large parking lots, pavements and sidewalks could be constructed using permeable, highly-porous materials that allow water to seep through its surface and become groundwater or drain into drainage systems. In fact, such a solution – developed by chemical company BASF as Elastopave – has already been implemented in beachfronts in Pattaya, Thailand. It even won Thailand’s National Innovation Agency’s “National Innovation Award” and will be installed in all beach projects along the country.
This solution is also commonplace in Korea, where it is used to construct sidewalks. In Erftstadt, Germany, 750 square metres of cycle path has been constructed using Elastopave. Malaysia would be wise to follow in their footsteps. This would be an ideal solution for concrete jungles such as Kuala Lumpur, Penang and Johor Bahru.
After decades of spending billions on cleaning up after floods and loss of life and damage to property, it is time the government spent a substantial sum upfront to get rid of the problem once and for all, or at least reduce it to an insignificant level, through these and other practical approaches.
Source : FMT