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Selection of a Local Flood Warning System (LFWS) Selection of the type of local flood warning system most appropriate for a particular community should be based on an evaluation of the hydrologic characteristics of the watershed, the frequency of damaging floods, the warning time vs, benefits, the need for other hydrologic capabilities, and the cost of the system. Automated flood warning systems cost more but can provide greater benefits, including the ability to meet other hydrologic forecast needs, Manual systems are inexpensive but limited in their capabilities. In the selection process, the accuracy, warning lead time, and reliability requirements should be determined, Accuracy and reliability affect the credibility of warnings and the extent of actions that can be taken in response to them. The costs of flood response actions must be balanced against the accuracy of the warnings and confidence in the local flood warning performance, The reliability of the local flood warning system is an important factor. Electrical and telephone service is disrupted during moderate or severe floods, Power disruption or the failure of gages or other elements may limit the usefulness of a system, so care must be exercised in selecting the components, The planning must also include consideration of a backup operation, Community Interest and Awareness A vital factor in assessing the usefulness of a local flood warning system is the interest and awareness of the local population, If a local system is to function properly, community interest must be active and sustained, Failure to maintain a high level of community awareness and interest in flood problems not only limits the effectiveness of a local flood warning system, but usually leads to its failure, An information program should be started and maintained to acquaint floodplain residents with actions to take when a warning is given, The information should be site-specific for each resident. Some floodplain residents would have to evacuate immediately, while others may have time to take steps to protect their personal property, All residents must be continually reminded of evacuation routes and centers where they can seek aid, 3. Local Flood Warning Systems A local flood warning system consists of four steps leading up to the determination that an imminent flood threat exists, and the dissemination of this information to local officials, The local flood warning system can be broken down into the following four steps: L Collect Data 2. Transmit Data 3, Forecast the Flood 9