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Feldu,an Ditch to an area just above station Tr-3a. Feldman Ditch originates on <br />the S-~ side of the x-i:•er and carried a small flow which eventually discharbed <br />• into the lower Steven: Gulch. A larger ditch,or_6inatingjust across the river, <br />too}; approxicately three-fourths of the river flow, lea:-ing only a small flow <br />remaining in the ri:•ar section surveyed. Conducti:2ties in this second section <br />were higher than the upstream section, for the river proper, (2?9 to 467 uhos vs <br />262 to 413 u}:os) and generally increased in a downstream direction. The sharpest <br />increases in conductivity came in a long pore' below the Delta Sand and Gravel <br />operation and appeared to originate as ground xater coming from the ;rl+f side <br />of the river. <br />Co~;oarisors <br />Data frog the p:evious s v; mont?:s showed a range of 135 - 77U uhos cc.. dared <br />to the 79 - 1032 fo•._nd during the kpril - October, 1g7o pe:zod. GeneraLy there <br />• was no evidence of significant differences in conductivity values between stations <br />in the earlier period (taldr:g into account apparent "slugs" of high conducti•r-ty <br />water)} however there is e:~.dence of station differences dur:.ng the present period. <br />Stations 'g 3a and Ar-4a showed :clues above 700 uhos on ten of the 25 sa•~pling <br />dates (April -October, 197E) compared to only one value above 700 uhos during the <br />previous six months. <br />Si~i''icance <br />T'nere are no state guidelines for corductivity, however high conductivity <br />is indicative of high le w 1s of dissolved scuds and salinity, which are of concern <br />in the Colorado Ei:~er basin. The average control station conductivities for the <br />present April -October period was approxiuately the same as averages for previous <br />• periods, however, the average conductivit}• at the downstream erd of the study area <br />was in the order of one third higher than control v-.lues. <br />3-12 <br />