Impact-based forecasting and warning services aim to bridge the gap between producers and users of warning information by connecting and increasing synergies between the components of effective early warning systems. In this research, we proposed an automated warning message based on colour codes to trigger risk mitigation actions at the local level in the flood-exposed communities of Kelantan river basin, Malaysia. With a community-based approach for different groups of users (i.e. sectors), flood-impact scenarios were determined from past events and related to colour codes. These were developed into impact-based forecasting and warnings that can connect water levels, through the colour code, to localised guidance information tailored to sectors’ needs on how to respond to the expected flood. Overall, the colour coded impact-based warnings were found to be an easy and understandable way to link water level forecasts to the necessary risk mitigation actions. However, further investigation is needed to validate these findings under real-time conditions. IBF has vast potential in Malaysia, but its integration requires significant institutional changes, such as an inter-facing agency (long term) or team (short term), adjusted policy frameworks (standing orders on disasters), and new resource allocations for skills development and technological innovation from national to local levels. Overall, this paper aims to offer the first insight into impact-based forecasting and warning services in Malaysia to trigger further research and project developments.

Tujuan utama pembinaan Terowong SMART adalah untuk mengurangkan kejadian banjir kilat di pusat bandar Kuala Lumpur. Banjir kilat di pusat bandar menyebabkan kerugian ekonomi dan menganggu aktiviti komersial bandar. Objektif kajian ini adalah untuk mengkaji keberkesanan Terowong SMART dalam menangani masalah kejadian banjir kilat. Kekerapan dan taburan banjir kilat di Kuala Lumpur dari 1984 hingga 2017 serta liputan kawasan Terowong SMART dianalisis dengan menggunakan Sistem Maklumat Geografi (GIS). Hasil kajian menunjukkan bahawa selepas Terowong SMART mula berfungsi pada tahun 2007, kejadian banjir kilat menurun, tetapi sejak 2010, kejadian air bertakung telah menjadi berleluasa. Hanya 7 kejadian banjir kilat telah direkodkan sejak pembukaan Terowong SMART tetapi di antara 2010 dan 2017, sebanyak 83 kejadian air bertakung telah dilaporkan. Terowong SMART telah memainkan peranan yang penting untuk menghalang lebih banyak kejadian banjir kilat daripada berlaku di pusat Bandaraya Kuala Lumpur. Walau bagaimanapun, masalah air bertakung harus ditangani secara holistik melalui perancangan yang berasaskan kepada pendekatan ekologi seperti yang digunapakai dalam pembangunan bandar raya sponge (sponge city development).