A panel formed to study solutions to increased flooding in Singapore has urged the government to require green roofs on new and retrofitted buildings. The 12-member panel, which was created after torrential rains caused flash flooding across eastern and central Singapore last year, said improved weather modeling and infrastructure improvements are needed to handle a surge in stormwater runoff caused by urbanization in Singapore. In the meantime, however, the panel urged simpler steps to reduce and delay flooding, including better storage tanks, porous pavements, and rain gardens. Such rooftop gardens, which are often added to reduce heat or for aesthetic reasons, can absorb six to 34 liters of water per square meter and limit water flow, local contractors said. After flash floods inundated large areas of Singapore last June for the second consecutive year, a government official warned that the nation’s drainage system is not equipped to handle the region’s “changing” weather patterns.