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<br />21 <br /> <br />studies (Osmundson et al. 1995 and Van Steeter 1996) showed that the spring <br />runoff in 1993, which peaked at 25,900 cfs, was capable of moving coarse bed <br />materials thereby winnowing accumulated fines from the channel substrate, <br />Osmundson et al. (1995) suspected that the earlier recommended peak of 23.500 <br />cfs would also be capable of moving bed materials. The results of another <br />study showed that a spring runoff with a peak of about 12,900 was capable of <br />flushing accumulated fine sediments from the bottoms of backwaters thereby <br />restoring their depth. Based on this information, the Service developed <br />recommended peak spring flows: <br /> <br />TarGet Peak SprinG Flows in the 15-mi1e Reach' <br /> <br />>23,500 cfs (5 in 20 years) <br />21,750 cfs (5 in 20 years) <br />16.700 cfs (6 in 20 years) <br />12,900 cfs (4 in 20 years) <br /> <br />The Service's 1995 year-round flow recommendations are summarized in Table 1 <br />as mean monthly discharges. Spring (April-July) recommendations are further <br />subdivided into 10-day increments and are reported in Table 2 as volumes of <br />water needed for each of twelve 10-day time periods. Variation in <br />precipitation levels from year to year is taken into account and <br />recommendations are provided for years of high, above-average, below-average, <br />and low snow fall. With the exception of winter, recommendations are for <br />flows considerably lower than historic levels but somewhat higher than recent <br />levels. <br />