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<br />. <br /> <br /> <br />.' <br /> <br />control of .954 and indicated an increase in precipitation of 39% over <br />\vhat would be expected without seeding. This is the equivalent of an <br />average additional 3.5 inches of precipitation over that portion of the <br />target during the seeded stoms. This percent excess is significant at <br />the .032 level (single tail) suggesting that these indicated increases <br />would only be expected due to chance in about 3 times out of 100. The <br />average control and target precipitation values are listed in Table 5. <br /> <br />The higher yield portion of the target covers about 750 square <br />miles (25 miles x 30 miles) or 480,000 acres. The calculated extra pre- <br />cipitation due to seeding over that portion of the target is about one <br />third of a foot (i.e. 3.5 inches). If all of this precipitation were <br />to run off, the contribution to the watershed would be 141,000 acre-feet <br />of additional water due to seeding. Assuming that evaporation and soil <br />conditions reduce the TIm off by one half, the contribution is still <br />70,000 acre-feet. A more conservative estimate of 30% runoff yields <br />42,000 acre-feet. <br /> <br />The linear regression for the lower yield portion of the target is <br />presented in Figure 7. As might be expected this does not correlate as <br />\veIl with the control (.71) as it is some distanl:e away from the coastal <br />stations. The apparent seeding effect from that area is about 42% excess <br />(about 1.4 inches increase due to seeding). The significance of these <br />numbers is low, however, suggesting that there is a high probability (25 <br />times out of 1~0) that the indicated excess could be due to chance. The <br />supportive data for the linear regression equation developed for this <br />part of the target area is listed in Table 6. <br /> <br />4.2 Evaluation of Streamflow <br />There are several rivers, streams and creeks that flow through the <br />\vatershed and it was felt that an analysis of the data would be useful <br />to corroborate the storm precipitation evaluation. Streamflow measure- <br />ment stations with long-tenn records were identified in the target area <br /> <br />4-13 <br />