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<br />I <br /> <br />I <br /> <br />six different ways. <br /> <br />Mr. Kroeger: Larry, give us your interpretation of the flood. This <br />hundred year flood, and so on. Would you do a little explaining on <br />that, please. <br /> <br />Mr. Starks: The statute uses the words "intermediate regional flood." <br />This s a common term used by the United States Army Corps of Engineers. <br />It is a type of flood upon which some historical evidence is available. <br />'It is based upon a statistical average of there being only a one per- <br />cent chance that this amount of rainfall will be equalled or exceeded <br />in anyone year. And that is where we get the term "a hundred year <br />flood." When you convert the one percent chance you come up with a <br />statistical average of that flood occurring only once in a hundred <br />years. An intermediate regional flood is actually a flood upon which <br />valid historical evidence is available. We don't like the term <br />''hundred year flood" because we think it is extremely misleading. A <br />hundred year flood could occur ten years in a row. It is not likely <br />to, but it can occur in successive years. There is a fairly well <br />standardized procedure to develop the hydrologic characteristics of <br />this type of flood. The terms are misleading. We have had some floods <br />here in Colorado in recent years which have exceeded the intermediate <br />regional flood. That is the best I can describe it. <br /> <br />Mr. Kroeger: And that evidence is taken from rainfall and actual <br />measurements of what? The floodplain areas? <br /> <br />Mr. Sparks: Rainfall and snowmelt runoff and the probability of the <br />two occurring together. <br /> <br />Mr. Vandemoer: Fred, I have another question. <br /> <br />Mr. Kroeger: Herb. <br /> <br />Mr. Vandemoer: Larry, again, I guess everybody is interested in their <br />own area. If the Narrows Dam would go in for instance, would this <br />chanse existing floodplains? <br /> <br />We can make a floodplain <br />year from now because <br /> <br />Mr. Sparks: Floodplains change continuously. <br />study today and it may be completely invalid a <br />of dams, highway bridges, or whatever. <br /> <br />Mr. Vandemoer: If the Narrows project is built, this will change the <br />floodplain below. How does a person go about getting his land out of <br />the floodplain if this happens? Do you see what I mean? <br /> <br />Mr. Sparks: Yes. We simply redesignate the revised floodplain. We <br />are doing this all the time. The best example is on the South Platte <br />below Chatfield Dam. If we complete that project, the floodplain will <br />shrink considerably. So we will have to redesignate it based upon the <br />new chara~teristics. This is a continuing process. <br /> <br />-7- <br />