This manual is based on the experience of German Technical Cooperation (GTZ) in a project supporting the establishment of Local Flood Early Warning Systems. The European Commission and the German Government funded the project. The manual describes how to set up and run a Local Flood Early Warning System for inland river floods. It does not include special cases like flash floods, storm surges and tsunamis.
Major river basins with flood prone areas have long been taken cared of by an institution of the Department of Science and Technology (DOST) handling mainly weather and flood forecasts, the Philippine Atmospheric Geophysical and Astronomical Service Administration (PAGASA). These early warning systems are technically demanding, highly automated and require heavy investments. The operations center, where information is gathered and decisions are made, is located in the central office of PAGASA in Manila. For smaller rivers and smaller flood-prone areas another approach has been successfully tested for some years now. The technical set-up is less sophisticated and thus much cheaper. The operations center is based in or near the flood-prone area and staffed with local personnel. Rainfall and river level data are observed and reported to the operations center. Automated gauges play a key role in the system and are augmented by local observers (mostly volunteers). In the experience of the local partners of GTZ (provincial government, municipalities) the system can forecast flood events and warn people in the hazard zone reliably.
Sometimes Early Warning Systems are called Warning Systems only, because it is the very nature of a warning to come earlier than the actual event. Therefore an early warning is a little redundant, but as this term is established and widely accepted now we also use it here.
Local Flood Early Warning Systems (LFEWS) have also been promoted by PAGASA and other institutions for a few years now. They are called Community-Based or Community Managed or simply Local FEWS to distinguish them from the big centralized FEWS run by the PAGASA central office.
There is a growing interest in the establishment of local and low-cost FEWS. Up to now no comprehensive guideline on how to establish and run such a system exists in the Philippine context. Some publications are dealing with the topic and many publications from countries with a history of big floods like Bangladesh provide guidance. It is hoped that GTZ can contribute with this manual to the development of more local flood early warning systems.