FLOOD02417

• County: Statewide
• Basin: Statewide
• Title: Guidelines on Community Local Flood Warning and Response Systems
• Date: 8/1/1985
• Prepared For: US
• Prepared By: Hydrology Subcommittee
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

rainfall data are collected upstream from a community. Data are then

transmitted to a central collection point. This information is used to

predict the magnitude of expected flooding, where flooding will occur, when

flooding will begin, when the crest will arrive, and when the stream will

recede below flood stage. This provides potential threat information and the

warning time that is critical for Federal, State, county, and local

organizations to take action to preserve life and property.

.

Within both manual and automated systems there are many approaches,

techniques, and variations that can be applied to meet a particular

community's needs. The generic classifications of manual and automated are

presented here for ease of description. Many installations contain a mix of

automated and manual components. Since each watershed is unique and community

needs vary, a simple classification of automated or manual systems is not

strictly possible.

Manual local flood forecast systems consist of: (1) a data collection system;

(2) a community flash flood coordinator; (3) a simple-to-use flood forecast
procedure; and (4) a communication network to distribute warnings to

appropriate emergency response officials, including the mass media and the

National Weather Service (NWS). The forecast system should be linked to a

community response system. Figure 7 illustrates the concept of a manual self-

help local flood forecasting system. Although these systems are simple to

operate, their continuous operation over long periods of time may be

difficult, especially in areas where flooding is infrequent. They can be

surprisingly accurate when adequate data are available.

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