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<br />Step 1 has been discussed in Chapter 3 of this manual.Steps 2-4 will be dis- <br />cussed in this section. Plans for Steps 5.7 should be developed in conjunc- <br />tion with all local law enforcement and emergency preparedness agencies, <br />the Colorado Division of Disaster Emergency Services (DODES), and FEMA@ <br />The CWCS and the other agencies can assist communities in developing <br />and improving floodplain emergency preparedness plans. <br />Floodplain emergency plans can incorporate appropriate information <br />regarding any dam failure flood zones in the community. <br />Flood Forecasting <br />Few communities or individuals will receive 24-hour notification of a pend- <br />ing flood disaster. Flood victims have only a few hours of warning, if any, of a <br />potential disaster. Reliable, accurate. and timely forecasts of floods by <br />Federal, State, or local officials are essential for timely evacuation. <br />Flood detection involves the sensing of physical phenomena such as <br />massive cloud build-up, heavy rainfall, or rising streamflow through <br />instruments and/or visual observation. Those data must then be transmitted <br />to an operation center or a command location where a decision can be made <br />regarding the type of alert that should be issued. The NWS has been charged <br />by law with the responsibility for issuing weather alerts based on <br />atmospheric conditions observed by their detection equipment and staff. <br />The messages which will be issued by the NWS are: <br />FLOOD WATCH Existing climatic conditions are favorable for heavy rainfall <br />to occur. Observers should be kept informed and be ready for immediate <br />action. <br />FLOOD WARNING Flooding is imminent or in progress and the publiC <br />should take prompt action if they are in the alert area. <br />The NWS issues a "Flood Watch" or "Flood Warning" based on immediate <br />conditions as they know them. Flood Watch implies there is some time to <br />plan appropriate action while Flood Warning implies immediate action is <br />needed. <br />A community's forecasting system can be designed to provide forecasts <br />about conditions that would increase the likelihood of dam failure floods, <br />such as heavy rain or snowpack, a high reservoir level, or indications of struc- <br />tural deficiencies in the reservoir system. Having such a forecasting <br />capability requires some aCtions by local officials. First, they can contact the <br />State Engineer's office, along with consulting U.S.G.S. 7 1/2 minute quad- <br />rangle maps, to inventory dams above their community. Once the inventory is <br />complete. they can consider preparing dam failure flood zone maps for all <br />dams other than the high hazard dams. They can also consider requesting <br />that dam owners prepare these maps. The local officials can attempt to <br />assure that the appropriate local official(s) are kept aware of any important <br />changes in the condition of the dam or other reservoir features. <br />Flood Warning <br />Flood Warning Systems <br />A community may want to develop a localized flood warning system. There <br />are basically three flood warning systems which may be considered. <br />DO NOTHING SYSTEM Rely upon the NWS for detection and dissemina- <br />tion of the warning to the local news media; rely on local sheriff and police <br />departments for action. $ = zero. <br />VOLUNTARY SYSTEM A team of predesignated local officials or residents <br />collects precipitation and streamflow data and transmits it to a local coor- <br />dinator. The coordinator makes a determination of the flooding potential and <br />notifies the NWS. The field equipment will consist of rain gauges and staff <br />gauges painted on stable vertical abutments. This system relies completely <br />on the human or NWS detection of a flood event. The local coordinator and <br />NWS disseminate the warning to the news media and the local sheriff and <br />police departments. $ = less than $5,000. <br />FULLY OPERATIONAL TELEMETRY SYSTEM This system would be self- <br />contained with only a minimum degree of reliance upon other agencies or <br />communication sources. The community would have a system which would <br />detect early rainfall and stream-rise developments. The content of the warn~ <br />ing wouid be based on the expertise and experience of the local forecaster. <br />A system of this type consists of the following equipment: <br />1) an independent power source, <br />2) early detection devices - automatic rainfall and stream gauges, <br />3) transmission stations, <br />4) receiver and decoder facility, <br />5) mini-computer and display screen, <br />30 <br />