Laserfiche WebLink
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/1 was predicted, while a value of 2570 mg/1 <br />was observed this year. In the Sage Creek alluvium at Well WSAL12, a <br />value of 972 mg/1 was predicted, while a value of 770 mg/1 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 1645 mg/l, while the predicted value <br />was 1299 mg/l. The value observed was determined gravimetrically (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/1, the calculated dissolved-solids value may be <br />preferable to the residue-on-evaporation value". The calculated <br />dissolved solids value is determined by adding up all the concentrations <br />for all of the various dissolved constituents. For May-September 2007, <br />the calculated TDS average value is 1575 mg/1. Drought conditions from <br />previous years may have contributed to the elevated TDS values. As <br />previously noted, the upstream Well WHAL10 has TDS values below its <br />predicted value. <br />- Wadge Overburden. Four wells monitor the Wadge overburden. Well WOV14 <br />exhibits an increasing TDS trend. Well WOV16 displays an increasing TDS <br />trend. Prior to October 1994, there was not enough water to sample in <br />this well. Therefore, all samples represent postmining conditions <br />(mining began in this area in 1990). There is still often not enough <br />water to sample in this well, the last sample was collected in May 2006. <br />Well WOV17 exhibits a decreasing TDS trend, with TDS values decreasing <br />since 1998. A new Wadge overburden well, WOV25, was drilled in September <br />2004. It displays a decreasing TDS trend. <br />f~ <br />