Laserfiche WebLink
• July 1993 -17- 923-2515 <br />selenium, and zinc. In the discussions of water quality, the units of measurement from the <br />monitoring sites are adjusted to facilitate comparison with those presented in the guidance <br />document for material damage assessment (CIVII.RD 1988). <br />Conductivity values range from 1.15 mmhos/cm at site YSGFS to a high of 3.2 mmhos/cm at <br />site SP-1. These values exceed the material damage suspect level of 1.0 mmhos/cm for the <br />Yampa River basin (CMLRD 1988). The data for the trace element boron which range from <br />0.07 mg/1 at SW-S2-1 to 0.25 mg/1 at SP-1 aze below the suspect level of 0.5 to 1.0 mg/1 given <br />by CMLRD (1988) for the sensitive crops wheat and barley. Chloride ranges from 7.13 mg/1 <br />at site YSGFS in upper Grassy Creek to a high of 134 mg/1 at site SP-1 in lower Grassy Creek. <br />These values are below the chloride suspect level of 250 mg/1. The suspect levels for aluminum, <br />manganese, nickel, and zinc are pH dependent and do not occur for a pH above neutral, 7.0. <br />• Since the pH at all sites ranges from 8.1 to 8.5, there is no adverse impact. The values for <br />arsenic, cadmium, copper, lead, molybdenum, and selenium aze well below the suspect levels. <br />The data for ground water quality aze from four permanent monitoring sites off the project site <br />in upper Grassy Creek west of Windy Point Road, YGAL15, YGAL16, YGAL17, and <br />YGAL18, and from two same-day, down-drainage samples: WRD-2 in upper Grassy Creek and <br />WRD-3 in lower Grassy Creek (Figure 2). The laboratory results for 39 water quality <br />parameters at each site aze presented in Tables 5.7 through Table 5.12. Parameters measured <br />include conductivity, sodium adsorption ratio (SAR), boron, chloride, aluminum, arsenic, <br />cadmium, copper, lead, manganese, molybdenum, nickel, selenium, and zinc. Conductivity <br />ranges from 1.05 mmhos/cm at station YGAL16 to 4.18 mmhos/cm at station YGAL15. These <br />values exceed the conductivity suspect level of 1.0 mmhos/cm (CMLRD 1988). Further, wheat <br />and barley will not germinate at values higher than 4-5 mmhos/cm (Gonzales 1993). The values <br />for boron range from 0.06 mg/I at YGAL16 in upper Grassy Creek to 0.23 at WRD-3 in lower <br />Grassy Creek and are within acceptable units. The pH ranges from 7.78 at YGAL15 to 8.15 <br />• at YGAL16. As discussed earlier, at pH above neutral, there is no adverse affect for aluminum, <br />Golder Associates <br />