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<br />Section 5.03. Runoff volume frequency curves <br /> <br />1 <br />1 <br /> <br />I <br /> <br />The varying characteristics of runoff volume vs. duration at any <br />location can be effectively represented by a set of runoff peak and <br />volume frequency curves developed as described in Volume 3 and illus- <br />trated in figure 5.01. Floods that dominate the peak-flow and short- <br />duration-volume curves are not necessarily the same ones that dominate <br />the long-duration volume curves. Yet, a set of values for peak flow and <br />each duration that have the same exceedence probability would represent <br />the same degree of severity as defined in Section 5.01. Such a set of <br />values, possibly with interpolated values added. can be used as described <br />below for the construction of a balanced hypothetical flood. <br /> <br />, <br /> <br />Section 5.04. Representative hydrograph <br /> <br />Even though a balance is obtained among runoff peak flow and volumes <br />for various durations at a given location, the time sequences of flows <br />in a hypothetical flood that would .ake up this balance can be any of a <br />great variety of time sequences. For example, flows could rise rapidly <br />and recede gradually or vice versa, and still retain the same volume-vs.- <br />duration relationship. Although this item is of secondary importance, it <br />does have some influence on design and therefore should be considered <br />carefully. This can be done by studying the relative timing of maximum <br />volumes for specific durations in relation to the time of peak flows for <br />the largest floods of record. A representative discharge sequence can <br />then be selected from among recorded floods. This would be represen- <br />tative only with respect to flow sequences and not with respect to ab- <br />solute or relative magnitudes of flow for various durations. <br /> <br />5-02 <br />