Laserfiche WebLink
RULE 2 PERMITS <br />Potential Impacts to Water Quality <br />The quality of surface water, springs and seeps and groundwater is described in Sections 2.04.7 (1) and <br />2.04.7 (2). This section evaluates potential impacts of mining to water quality including: <br />• Potential effect on stream water quality <br />• Potential effect on spring and seep water quality <br />• Potential effect on groundwater quality <br />Potential effect on stream water quality <br />As described above, Little Collom Gulch is ephemeral, and showed no evidence of surface flow during 18 <br />months of baseline monitoring. As a result, no water quality samples are available. <br />There may be periodic releases of water to Little Collom Gulch from the North Pond sediment pond. <br />Most of the water released from the pond will probably infiltrate into the valley fill in the Gulch and will <br />result in little if any direct surface flow down to the mouth of Little Collom Gulch. Adequate settling <br />time will be provided in the pond to meet Colorado Point Discharge Elimination System (CPDES) <br />permitted discharge criteria. The water quality from any pond discharge is anticipated to be of higher <br />quality than the surface water quality seen in the lower reaches of the streams in the Collom area. No <br />surface water quality impacts to Little Collom Gulch or to Collom Creek as a result of surface water flow <br />from Little Collom Gulch are anticipated. <br />Periodic releases of water to Collom Creek from the Section 26 sediment pond may occur. This section <br />of Collom Creek is intermittent so some of this discharge may continue down the stream as surface water <br />flow. Adequate settling time will be provided in the pond to meet CPDES permitted discharge criteria. <br />The quality is anticipated to be of higher quality than the surface water quality seen in the lower portions <br />of the streams in the Collom area. Periodic discharge of water may occur from the Little Collom Gulch <br />diversion structures to Collom Creek and the West Fork of Jubb Creek. This water will be surface runoff <br />from undisturbed areas and will have a good water quality. No surface water quality impacts to Collom <br />Creek or to the West Fork of Jubb Creek from these potential releases are anticipated. <br />Any dewatering water entering the surface water system tends to have better water quality than the <br />surface water. This is based on a comparison of the ground water quality from C -04-16B (1613) versus <br />water quality data from Jubb Creek (JC) and Collom Gulch (CG), as detailed in the WMC report, 2005. <br />The water quality sample from 16B was collected after 500,00 gallons of water were pumped from the <br />welland is therefore a good example of the water that would be coming from the dewatering wells with <br />time. <br />In C -04-16B, the pH is approximately 7.2, while the pH is greater than 7.5 in JC and CG. The total <br />dissolved solids (TDS) are 710 ppm in 16B, while in the CG, the mean was 838 and in JC the mean was <br />1663. All water samples were high in bicarbonate, while the groundwater from 16B had higher sodium <br />than calcium, while the surface water had higher calcium than sodium. No heavy metals were detected in <br />the 16B water sample while the surface water samples from both streams had low levels of selenium and <br />manganese (approximately 0.10 ppm for both metals). Thus, except for adding excess sodium tho the <br />surface water, all other qualities are better. <br />Thus, the water quality will be improved for a short distance until it intermixes with any surface water. <br />Collom — Rule 2, Page 122 Revision Date: 1/6/17 <br />Revision No.: TR -109 <br />