2017-08-16_PERMIT FILE - C2010089A

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Overburden Zone Ground Water Quality Water level monitoring and the piezometric maps show the nearly immediate response of most of the twelve monitoring wells to the seasonal surface irrigation with water levels going up and down corresponding to the periods when water is in the 2nd Park Lateral Ditch. The impression is that the overburden is annually being flushed with relatively good quality irrigation water. This further suggests that water quality would improve during periods of irrigation and deteriorate during periods when the ditch is dry. However, comparison of the ground water quality data (see Appendix 2.04.7-1) with the water level data reveals no such correlation. Table 2.04.7-1 is a summary of the water quality analyses for the overburden, showing the minimum, maximum and average values of the analyzed parameters. No data for overburden monitoring well GW -N55 is shown as this well was nearly dry to the point that there was not enough water to collect water samples. The summary of the analyses for wells GW -N49 and GW -N52 are also compared with the WQCC (Regulation 41, The Basic Standards for Ground Water) drinking water and agricultural quality standards. The results show the overburden water quality to be unsuitable for domestic drinking water primarily for sulfates. With the exception of calcium and bicarbonate, the water quality at GW -N52 is better than that at GW -N49, most probably the result of being located closer to the seasonal more alkaline recharge from the 2nd Park Lateral irrigation ditch. The values for pH at GW -N52 are also somewhat higher (more alkaline). Again, suggesting that being closer to the main source of recharge (the ditch) affects the water quality to a greater extent at GW -N52 than at GW -N49. Coal Zone Ground Water Quality Quarterly groundwater quality samples were collected from the three wells (GW -N48, GW -N51 and GW -N54) beginning on October 10, 2008. The groundwater quality data is contained in Appendix 2.04.7-1 along with the water level and graph information. Review of the coal zone quality does not clearly reveal any correlation with the irrigation seasons, although there is a slight increase in Ca, CaCO3, SO4 and total dissolved solids (TDS) during the winter months when the ditch is not running. It may require a few more seasonal irrigation cycles to validate this initial impression. Again, the monitoring well located furthest up -dip and closest to the recharge area (GW -N51) has better water quality. As an example, the average TDS at GW -N51 is 950 mg/1 compared with an average at GW -N48 of 1,592 mg/1 and an average TDS at GW -N54 of 5,058 mg/1 which is located the furthest down -dip and away from the recharge area. Table 2.04.7-2 is a summary of the Coal Zone ground water quality showing the min/max and average parameter values since monitoring began. Water quality for the Coal Zone at GW -N54 is the poorest of quality of all twelve of the monitor wells. The values when compared with the WQCC water quality standards clearly show that water from the Coal Zone is unsuitable for domestic drinking water. Section 2.04.7 Page 9 April 2016 (PR -01)