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Conductivity <br />A•C SllltS <br />Conductivity values on the North Fork ransed from 79 - 1032 uhos (based on <br />32 sampling dates during the April - Nover;oer per-mod). Ln general, conductivity <br />was low from April to mid-July. oalues ranged frcm 79 - 155 uros and mean values <br />Sor each of the stations were approric;ately 110 uhos. In general, the low con- <br />ductivity periods corresponded to the high spring Slows. triter mid-July, con- <br />ductivity was is the order oS 2 - 8 times the spring average, with a few values <br />greater than 800 uhos. t;ean values during the mid-July throuE;h October period <br />wez~ in the order of 3-1~2 to 6 times mean values o" the earlier period; and <br />tdover„ben values wore in the order oS 2 - 3 tines that of the April -tray period. <br />I}iSfererces bet'+:een conducti~~ity •,2.lues at several stations were e+,-ident <br />during the July - November period 'out not during the April - 1:ay period. <br />Stations it-la a^.d I;F-2b xe:tl s~-;gar arm' '_cw_r than stations 2'F-3a 2zd -!.a <br />• for both the mid-July to late October and late October throw ;;ovecber periods. <br />t4ean values are shown i-~ Table 1. <br />The m,xing zone, station ;7F-lb, was not significar:tly different from NF-La <br />or N.innesota Creed (t:C-1). <br />Figures 2 and 3 show the results oS sampling conuctivity at Srequent spatial <br />intervals along the Borth Fork in late tlovember. Two sections were surveyed. <br />The first section covered the area Sroa the control station, 1.TF-la, to near <br />station A'F- Zb. Conductivity in this area ranged from 203 to 625 uhos and generalJ,y <br />increased in a downstream direction. Sources of higher conductivity were apparently <br />from gro-and water. S:uall flows from the gro,u,d-water-fed pond near the coal load- <br />mst area showed high corauctivities (62o uhos) as did a drainage a short distance <br />. downstream. The Latter also apparently o ginaied as ground water a short distance <br />away, based on its higher temperature compared to North Fork surface waters. <br />The second section surveyed covered the ?dorth Fork Sroa the beginning of <br />3-11 <br />