Laserfiche WebLink
<br />commencing within the permit boundary and extending into the Dos Hermanos Ranch <br />property situated directly west. Large continuous areas were inundated as a resuR of the <br />dams' construction. The wetlands type and extent fcnneriy documented within this area <br />of the Rito Seco may be in transition due to its continuous inundation. A segment of <br />contamination of approximately 1.1 miles was delineated with SI samples BM-SW-02 and <br />BM-SW-03 collected from the Rito Seco River. The segment of contamination includes <br />approximately 0.3 miles of contiguous seasonally flooded, palustrine scrub-shrub <br />wetlands. <br />The Rito Seco River is a historical fishery (BMG, 1988). The Salazar Reservoir was <br />reported to be a cold water fishery containing human food chain organisms such as <br />Brown and Rainbow Trout and Kokanee Salmon (URS, 1993). At the time of SI sampling, <br />the Salazar Reservoir was completely dry. <br />6.0 GROUND WATER MIGRATION PATHWAY <br />A quarterly ground water montoring program consisting of wells located upgradient and <br />downgradient of site sources maintains a check on local ground water quality. Ground <br />water is monitored from the Rito Seco alluvium, the Santa Fe Conglomerate and the <br />underlying Precambrian Gneiss. Analytical parameters include dissolved metals, weak <br />acid dissociable (WAD) and total cyanide, major ions and pH. Analyses of ground water <br />from onsite monitoring wells revealed the presence of cyanide, mercury and manganese <br />in vicinity ground water. Cyanide has been detected at a concentration of 1.5 ppm in a <br />sample collected from monitoring well M-12 cyanide. A total cyanide concenmation of 3.5 <br />ppm was detected in a sample collected from monitoring well M-14. Both samples were <br />re-analyzed at a later date and were determined not to contain detectable cyanide; <br />however, re-analyses were conducted signficantty after the standard 14-day holding time <br />for cyanide analyses (EPA SW846). Mercury was detected in onsite monitoring wells M-9 <br />and M-13 (CDMG, 1994b). <br />Manganese has been detected in Rito Seco alluvium ground water collected from <br />monitoring wells M-10 and M-11 at concentrations consistently exceeding the reference <br />dose screening concentration benchmark for manganese of 0.180 pg/L (SCDM, 1994). <br />Samples collected from monitoring wells screened in the Santa Fe Congomerate have <br />contained manganese at concentrations varying from below detection limits to above the <br />reference dose benchmark, Since all monitoring wells are situated within the Battle <br />areo~teoo~.mrmmRr - 7 - (R.+4oi/fWp9 <br /> <br />