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<br />the frequency interval calculation method yields more accurate <br /> <br />results for the lower end of the curve, which is usually flatter, and <br /> <br />represents less frequent flood events, than for the upper part, which <br /> <br />is usually more convex, and represents the more infrequent events. <br /> <br />Even if it could be argued that, over the entire range of the curve, <br /> <br />the pluses and minuses of areas tend to cancel each other out, EAD <br /> <br />would still be distorted since the component of EAD contributed by <br /> <br /> <br />more frequent events is. more heavily weighted by the higher <br /> <br /> <br />probability than those for the more infrequent events. Even so, we <br /> <br /> <br />can conclude that if sufficient data points are used, the frequency <br /> <br />interval calculation method will yield reasonably accurate results, <br /> <br />since distortions occur primarily for the more remote events. <br /> <br />WHY EXPECTED ANNUAL DAMAGE? <br /> <br />It is important to know why the computed value is considered to <br /> <br />be an annual value over the study period. The three basic functions <br /> <br />used to determine the damage-frequency relationship, i.e., the stage- <br /> <br />damage, stage-discharge, and discharge-frequency curves, under <br /> <br />existing conditions, are derived based on existing hydrologic and <br /> <br />economic conditions. The damage-frequency curve, employed in EAD <br /> <br />computation, was generated from these three curves. In other words, <br /> <br />the probability of occurrence of each event, in a given year, was <br /> <br /> <br />used to define the probable damages in that year, based on the <br /> <br /> <br />conditions that prevailed at that time. For example, the probable <br />damages associated with a lOO.year and a IO-year event are, <br /> <br />respectively, .01 and .1 times the damages estimated for each of <br /> <br />V-60 <br />