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<br /> <br />1 <br /> <br />1 <br />t <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />5.5 Impacts Due to Amended Application Only <br />The impacts to the aquifer-stream system relationship brought about by mining the new areas <br />covered under the amended application aze shown in Table 5. For the 478 acres of mined azea where <br />the alluvium may be removed, roughly 158 ac-fr of water historically flowed out of the streams to <br />rechazge the alluvium, primarily during the months of April and May. Summer water levels stayed <br />fairly constant until August while irrigation was continuing, with small flows into or from the <br />streams. The same amount of flow (roughly 158 ac-fr) was discharged back to the stream from the <br />alluvium, mostly between September and Mazch. In the future, roughly 5.6 acres of unlined pit will <br />be created toward the north end of the property (see Figure ]); this pit will continue to provide an <br />alluvial storage function as it will remain in contact with the stream system. However, only about <br />12 ac-fr will flow from the stream to rechazge the pond, again primarily during April and May. The <br />same 12 ac-ft will be discharged from the pond back to the stream when water levels decline <br />between September and March. Therefore, the new mining operation will result in about 146 ac-fr <br />(158 ac-fr minus 12 ac-fr) less alluvial storage. The loss of the storage will result in more flow in <br />the stream during the historical recharge period in the spring and less flow in the strer m durine the <br />fall and winter when the alluvium typically discharges back to the streams. The greatest increase in <br />flows will be in Mav, when 87 ac-fr more flow will remain in the stream, on average (about 1.46 cfs). <br />The decrease in streamflows will be greatest in September when 53.6 ac-fl less flow will discharge <br />to the stream (about 0.87 cfs}. <br />5.6 Impacts Due to Total Mining Operation <br />As discussed previously, when considering the changes to the alluvial aquifer-stream system <br />relationship brought about by the Lyons - Rockin' WP Pit, it is important to consider not only the <br />impacts brought about by the amended application, but by the operation as a tivhole, a~nsidering the <br />already permitted azeas. The analysis presented above for the mined areas coverf:d by the new <br />amendment indicates that there are potentially significant impacts in streamflow brought about by <br />the elimination of alluvial aquifer storage on the mined lands which aze the ~;ubject of the <br />_28_ <br />/li.</np~/lnrdru .I ;;urvntr~. /rrc <br />