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<br />e <br />\.,...- <br /> <br />. <br /> <br />!e <br /> <br />e <br /> <br />arrange in appropriate order around the maximum value. This is repeated for <br />each of several storm frequencies such as the 50-percent, la-percent, <br />2-percent, I-percent events (Le., the 2-year, 10-year, 50-year, lOo-year <br />recurrance intervals). These become the hypothetical storm inputs. Point <br />rainfall values should be adjusted to the appropriate areal size using the <br />guidelines given in Chapter 4, <br /> <br />(6) Assign Frequency to Hypothetical Events at Gaged Sites <br />USe the hypothetical storm data of Step (5) as input to the calibrated <br />model of Step (4) and generate peak discharges at whatever gaged 10catiDns <br />may be available for selected rainfall frequencies, compare the results with <br />discharge-frequency curves at the gaged locations if these are available, <br />Adopt indicated frequencies for hypothetical events or adjust IDSS rates in a <br />IDgical manner until reasonable agreement is obtained between the tWD <br />frequency curves. <br /> <br />(7) Determine Point Runoff and Frequency for Desired Locations <br />Using the loss rates established in Step (6), generate peak discharges <br />for each subbasin and combining point throughout the basin, Separate runs <br />are required for each frequency and rainfall distribution pattern, but the <br />jobs can be stacked so that they are all processed at one time. Plot the <br />peak diSCharge values vs exceedence frequency on a log-normal probability <br />paper and interpolate to get other discharge freQJencies, if they are <br />desired. Compare results with those available from other methods and adopt <br />final values. <br /> <br />Procedure B - Regional Unit Hydrograph Parameters Available <br /> <br />If regression eQJations for regional unit hydrograph parameters are <br />already available, Procedure A can be followed, but Steps (1) and (2) can be <br />omitted. Because there are no observed data within the basin under study, <br />streamflow-frequency curves should be developed for near-by basins by <br />treating the area above each gage as a single subbasin (Step (3)). Step (4c) <br />will also be omitted in this procedure. <br /> <br />15 <br />