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Attachment <br /> POND #5 <br /> Given: permeability values of 1 x 10-7 <br /> cm/sec and 2 x 10-7 cm/sec <br /> Given: pond #5 constructed in January, 1982 <br /> Assume: worst permeability value of 2 x 10-7 cm/sec overall <br /> Assume: use of pond #5 since January and through August 1 = 7 mo. = .583 yr. <br /> Then the distance traveled by water through the liner in t = .583 yr. <br /> .585 yr. x j§_�da s x 24 hrs. x 60 min. x 60 sec. x 2x10-7 cm <br /> Fay— — — <br /> yr. hr. min. sec. <br /> 3.68 cm x in. X ft. .121 ft. per 1 ft. head <br /> 2.54 cm 12 in. <br /> Then, because maximum head = 81 , maximum distance traveled <br /> .121 ft. x 8 = .966 ft. or 11 .611 <br /> Conclusion: Because the pond may not have been used during all or any <br /> of January and because the pond has not had a full 8' of <br /> head continuously to date, the .966 ft. of liner penetration <br /> is a maximum calculated value, which is Still 41 ft. <br /> Perhaps a more realistic distance value may be calculated, assuming use <br /> of the pond beginning in February 1982 through August 1 , 1982 (= 6 mo. = .5 yr. ) <br /> and assuming an average head value = 6 ft. over this span of time: <br /> Then distance = .5 yr. x 365 = 24 x 60 x 60 x 200-7 = 3.15 cm. <br /> = 1 .24 in. = .103 ft. per 1 ft. of head <br /> = .103 ft. x 6 = .620 ft. or 7.411 total <br /> Conclusion: If the minimum thickness of liner in pond #5 is 1 ft. (along <br /> the berm between this pond and ponds #1-4), then this .620 ft. <br /> liner penetration value is fairly close to the safe "halfway" <br /> distance of .5 ft. 'of liner. So, I think we can safely approve <br /> the use of pond #5 until August 1 . <br /> LLS:sb <br /> 6-3-82 <br />