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Susan Mowry <br />April 22, 1986 <br />Page two <br />concluded that part of the elevated total iron was from the springs. The <br />primary source appears to be associated with the newly excavated soils stockpiled <br />in the pond and the resulting increase in total suspended solids. The first <br />quarter of 1986 shows a sharp decrease in total iron as well as total suspended <br />solids. The future trend is expected to remain near or below 0.5 mg/1 total <br />iron. The water level will be kept higher than during construction suppressing <br />low head springs and giving longer settling times. The lack of mine discharge <br />will also contribute to longer settling times. This trend prediction may <br />not be applicable due to our request to eliminate Pond No. 1. <br />An initial estimated maximum impact of the underdrains on Hubbard Creek low <br />flow conductivity is to increase the Creek level by 7.2 umhos/cm. This calculation <br />was made assuming low flow in Hubbard Creek of 1.6 cfs and maximum discharges <br />from the subdrains to date of 0.5 gpm @ 1656 pmhos/cm for the north drain <br />and 1.4 gpm @ 3100 umhos/cm for the south drain. Further analysis will be <br />made in the 1986 Annual Hydrologic Report. <br />If there are any further questions, let me know. <br />Sincerely, <br />Larry Reschke, P.E. <br />Project Engineer <br />xc: Jim Stover <br />