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tributary) below NPDES 006. TDS values at this well display an <br />increasing trend. <br />One well monitors the 005 Gulch alluvium (tributary to Dry Creek). This <br />well, WDAL11, is normally dry. <br />Three wells monitor the Sage Creek alluvium. Well WSAL12, located on <br />Sage Creek adjacent to Surface Water Site SW-S2-FG4 (WSSF3), is <br />downstream of all mine discharges on Sage Creek. TDS values at this well <br />had been increasing since it was drilled in 1990. Well WSAL13 is located <br />below NPDES 009 on the northern Sage Creek tributary (this NPDES site, <br />constructed in 1991, started flowing for the first time ever in 1996). <br />There is often not enough water to sample in this well, but there was <br />enough water to sample in May of 2008 and 2009. This well displays a <br />decreasing TDS trend. Well WSAL14 exists on the southern Sage Creek <br />tributary below NPDES 015 (constructed in August 1999, first flow <br />February, 2000). Monitoring was resumed at this well in May 1998 after <br />being discontinued in October 1995. It displays a decreasing TDS trend. <br />In the Probable Hydrologic Consequences section (PHC:, Tab 17) of the <br />Seneca II-W PAP, predictions were made for the May-September average TDS <br />values at various alluvial wells. In the 006 Gulch alluvium at Well <br />WHAL10, a value of 3394 mg/l was predicted, while a value of 3160 mg/l <br />was observed this year. In the Sage Creek alluvium at Well WSAL12, a <br />value of 972 mg/l was predicted, while a value of 835 mg/l was observed <br />this year. <br />The May-September average TDS value measured this year in the Hubberson <br />Gulch alluvium at Well WHAL7-2 was 1403 mg/l, while the predicted value <br />was 1299 mg/1. The value observed was determined grav.imetrically (i.e., <br />dry a water sample and weigh the residue). According to Hem (1989, pg. <br />157), "... it is not uncommon for water high in calcium and sulfate <br />concentrations to yield a residue after drying an hour at 180°C that <br />exceeds the computed dissolved solids by several hundred milligrams per <br />liter" and also, "In many instances, especially if the concentration is <br />greater than 1000 mg/l, the calculated dissolved-solids value may be <br />5