Singapore panel makes recommendations for mitigating flash-flooding

Storm water run-off, a major problem which has affected Singapore for two consecutive years, is thought to be partially due to urbanization of the country, and recommendations have been made for mitigation of this serious issue. An expert panel consisting of 12 members was created after last year's flash flooding across eastern and central Singapore to research potential solutions, and the panel explains that urbanization — that is, more concrete, buildings and roads due to a growing population — is one of the reasons behind the recent increase in storm water run-off which causes the flooding. Today Online mentions that the panel performed additional analysis as a joint effort with the Meteorological Services, and observed that there are clear trends in recent decades towards higher rainfall in terms of intensity and frequency. These findings are consistent with the Intergovernmental Panel on Climate Change's (IPCC) findings. The panelists determined that costly and potentially disruptive infrastructure improvements throughout Singapore are needed to handle the storm water completely, but they also recommended quick fixes that can delay and alleviate the flooding on a shorter timeline. These quick fixes include rain storage tanks, porous pavements, and rooftop gardens. Rooftop gardens can absorb up to 34 liters of water per square meter, according to Prince’s Landscape & Construction, a firm that specializes in building these gardens. The garden consists of soil-like material placed on top of membranes and storage trays, where rainfall is absorbed into the material and feeds plants growing in it. This intermediary between the rainwater and the surface of the building helps to slow down the speed and quantity at which it reaches the ground — thereby reducing flooding. Estimates from local Singaporean contractors say building a single rooftop garden can cost anywhere from $20,000 to $180,000, depending on the desired size. The EPA points out that rooftop gardens are useful in ways other than diverting and slowing rainwater from reaching the ground. They can reduce urban heat island effect, because plants provide shade and remove heat from the air. These gardens can also reduce energy usage, reduce air pollution, improve human health and comfort, and enhance a building’s aesthetics. Urbanization contributes to flooding because without porous ground to absorb water, like grass or dirt, heavy rain has nowhere to go but to the streets. As a result, damage is caused to roadways, buildings, homes, and people's health and lives are put in danger. Some of the risks to human health, pointed out by the CDC, include infectious disease, chemical exposure, electrical hazards, and animal bites. The panel did note that the effects of flooding are often complex and will require more research and analysis. Additionally, these quick fixes also need to be supported with other methods like diversion canals, drain capacity improvements and flood barriers. Panel Chairman Chan Eng Soon mentions that a non-physical defense measure would be to move toward a more integrated "risk-based" approach to improve on weather forecasting in Singapore.