Laserfiche WebLink
D. Streamflow values were overage values calculated from the baseline data far the <br />period June 1 to September 30 for all years of monitoring et the specific stream <br />monitoring sites located in the stream reaches being evaluated for impacts. In <br />the case of Y-1 Trit~utary, discharge values £rom Y-1 pond during the <br />above-referenced period were averaged. <br />E. Pit pumpage flow values were determined from the model output data presented in <br />Tables 17.2 through 17~~5 in Tab 17. The years of highest pumpage for each <br />drainage were selected. <br />F. Pit pumpage iDS values were average TDS levels for the representative overburden <br />and wadge coal wells in each drainage multiplied by the percentage of total <br />annual pumpage attributed to the overburden and wedge coal units. In the Grassy <br />Creek drainage, the overburden accounted for 93 percent of the total annual pit <br />i nfLow volume while in the Sage Creek drainage the overburden comprises 97 <br />percent of the total annual pit inflow volume. <br />G. The amount of pit pumpage entering either the Annand alluvium or (he r-1 <br />alluvium was teased on the amount of water level shellowin9 in representative <br />alluvial wells during snowme It runoff periods of comparable or greater floe <br />rates than the pit pumpage. the feet of water Level shalLowing at the <br />representative alluvial wells was multiplied by the same alluvial saturated <br />widths as described in A.1, above and the same hydraulic gradients and hydraulic <br />conductivities as previously addressed to calculate a pit pumpage portion of <br />flow within the alluvial aquifers. <br />H. The proportion of pit pumpage discharged from Pond 012 was calculated by <br />comparing the pond volume and natural runoff rate for January 1 through <br />September 30 against the greatest pit pumpage volume for the same period. the <br />percentage of the total volume attributable to pit pumpage was calculated to be <br />40 percent. <br />]I. Pit Pumpage Impact to Alluvial and Stream water quality in the Grassy Creek Drainage <br />A. Background Chemical Loads <br />1, Annand Draw Alluvium L=0.00004 cfs x 1291 mgll x 0.0027 = 0.000139 tons/day <br />2. Grassy Creek Alluvium 1=0.00046 cfs x 3648 mg/l x 0.0027 = 0.00453 tons/day <br />3. Annand Draw Streamflow L=0.0138 cfs x 950 mg/l x 0.0027 = 0.0354 tons/day <br />4, Grassy Creek Streamflow L=0.185 cfs x 823 mg/l x 0.007 = 0.411 tons/day <br /> <br /> <br /> <br />