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<br />....... <br />-.J <br />c.." <br />CD <br /> <br />discharges during a month, thus resulting in flow figures more <br />representative of "normal" habitat conditions. The monthly 80 <br />percentile figure, which is equaled or exceeded by the averages <br />for that month 20 percent of the time, was used to represent <br />dry years. It was assumed to occur one year in five. The <br />other four years were assumed to be median years. The result <br />was to give an estimate of impacts which tended to be conser- <br />vative in terms of instream flow. <br /> <br />. <br /> <br />e. Other Discharge Data Considered <br /> <br />I' <br /> <br />Monthly Median Based on Daily Averages <br /> <br />. <br /> <br />The CIFSG would have preferred to have used a median <br />monthly flow based upon the average daily discharges <br />during a given month for the period of record. Calculated <br />thus, the medi an removes even more of the effects of <br /> <br />extremely low or extremely high discharges and thus pro. <br />vides data more closely related to long term habitat <br />conditions. The BR analysi s begins with monthly means, <br />based of course, on daily means. But from there on, all <br />percentile figures, including the median (50th percentile) <br /> <br />are related to the monthly means. There was no way, in <br /> <br /> <br />the course of thi s assessment, to get back into the daily <br /> <br /> <br />averages for a determination of median monthly flow. <br /> <br />. <br /> <br />~iscussions with the USGS Automatic Data Services (ADS) <br /> <br /> <br />people at Reston, Virginia led to setting up the procedure <br /> <br />44 <br />