Laserfiche WebLink
<br />Sensitivity analysis has as its objective, the identification <br /> <br /> <br />of either (1) critical elements of data, or (2) particularly <br /> <br /> <br />sensitive system components, so that further studies can be directed <br /> <br /> <br />toward firming up the uncertain elements or that adjustments in <br /> <br /> <br />system formulation can be made to reduce the uncertainty. <br /> <br /> <br />Because of the particular method used in HEC-5C to develop <br />regulated conditions frequency relations at damage index stations, <br />particular attention must be paid to selection or development of <br />the system hydrology. The problem arises when evaluating complex <br />reservoir systems with many reservoirs above common damage centers; <br />the problem also increases with the size and complexity of the basin. <br />There are a large number of storm centerings that could yield similar <br />flows at a particular control point. Because of this, the contribu- <br />tion of a specific system component to reduced flooding at a down- <br />stream location is uncertain and dependent upon storm centering. <br />This makes the selection or development of "representative" center- <br />ings crucial if all upstream components are to be evaluated on a <br />comparable basis. The desired evaluation for regulated conditions <br />is the "expected" or average condition so that economic calculations <br />are valid. The representative hydrograph procedure used in f1EC-liC <br />where several proportions (ratios of one or more historic or synthetic <br />events is used to represent system hydrology) is compatible with <br />the simulation technique used but care must be taken to reasonably <br />accommodate the storm centering uncertainty. <br />28 <br />