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4000 <br />3500 <br />3000 <br />2500 <br />J <br />E 2000 <br />1500 <br />1000 <br />500 <br />Calamity Draw TDS vs. Flow <br />Flow (CFS) <br />Figure 2 - Calamity Draw TDS v. Flow <br />• SW-N108 <br />• SW-N109 <br />The Total Dissolved Solids (TDS) is also shown to be consistent between the upstream <br />and downstream sampling points. The data above is from 2001 through 2008. It shows <br />that the TDS varies more with respect to flow than anything else. The base flow in the <br />Draw is from 0-4 cfs. TDS under conditions both upstream and downstream is from <br />2600-3400 ppm. When flows increase due to storms, the TDS drops in a corresponding <br />way. For these reasons, we believe that semi-annual sampling of Calamity Draw is <br />warranted. <br />The current downstream location on Calamity Draw is a good measurement of the direct <br />effect that surface run-off from the eastern portion of New Horizon #2 Mine has on the <br />local watershed. However, a more effective sample point would be SW-N103, since <br />disturbance has moved west beyond sample point SW-N109 This point was sampled by <br />Peabody prior from 1981 to 1987, but was abandoned soon after. It is far enough <br />downstream that any samples taken from it would not only include the area served by <br />SW-N109, but it would also include areas to the west, specifically the Pond 008 <br />discharge. Therefore, Western Fuels will stop sampling from SW-N109, and sample <br />from SW-N103 instead. This sampling would be on a semi-annual basis, as would the <br />continued sampling of SW-N108. <br />5 10 15 20 25 30