Laserfiche WebLink
12 years from these sites has shown that the TDS of the waters drops significantly <br />when irrigation is active in the area. Therefore, the impacts to the receiving waters <br />will be studied for both cases, with and without irrigation. The irrigation case <br />corresponds to the September/October time period when flows are fairly low in <br />the San Miguel River. The non-irrigation period corresponds to March/April <br />when flows in the San Miguel are usually at peak. This is shown on Table <br />2.05.6(3)-4 in the permit application package. <br />The values for the NPDES 001 Discharge and SW-N3 are averaged from <br />measurements made from 1993 to present. Table 2.05.6(3)-3 in the permit <br />document shows this information for these as well as other sample points. <br />As is seen from this table in the permit, the spoil water inflows from both mine <br />areas i::fl?.zence the miality of T,wttle Draw to a m or dew PP TTn?z?eyPrr ?z?ithin <br />4500 feet, this flow enters the San Miguel River where the flow is so much larger <br />than the Tuttle Draw flow that the impact is negligible. During periods of <br />irrigation, Tuttle Draw is flowing at a higher rate while the River is running low, <br />which is the time of maximum impact of the flows. at this time, the increase in <br />TDS of the River is from 620 to 652 ppm, or an increase of 5.1%. It should be <br />noted that Tuttle Draw flows are always higher in TDS than the River, regardless <br />of the spoil springs, therefore, the impact from the spoil springs may be only 2- <br />3% increase in TDS. During March/April, the River is flowing fast and Tuttle <br />Draw is at low flow, therefore the increase in TDS for the River is only 2 ppm, or <br />an increase of 0.4%. Also, these impacts are for the time when the spoil material <br />is leaching salts at a maximum. As described earlier, the TDS levels will drop as <br />pyrite and salts are leached out of the spoil, lessening the impact to the waters <br />downstream even further. <br />Calamity Draw is not included in Table 2.05.6(3)-4 of the permit since the spoil <br />springs from both mine areas will not enter this stream. This intermittent stream <br />should not be affected in the long term by the mining and reclamation operation. <br />Overall, the effects of the spoil springs are not significant to the waters <br />downstream. All of the probable impacts have been determined to be of a short <br />term nature, of minimal significance, or a plan has been presented to mitigate <br />those determined to have some significance. As a result, mining and post mining <br />effects to current land uses should be negligible. <br />J. Water Rights <br />The water augmentation plan is found in Section 2.05.6(3) of the permit document. <br />Western Fuels - Colorado has acquired approval from the Colorado Water Court for <br />this augmentation plan and has a completed well permit for use of water from Pond <br />007. Demonstration for retention of Pond 007 is found in Attachment 2.05.3(3)-16 of <br />the permit. Attachment 2.05.3(3)-19 provides the demonstration for retention of Pond <br />008, which is located on property owned by Burbridge. <br />43