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Red Creek Quarry Baseline Water Investigation Section 6 <br /> <br /> <br />6-15 <br />DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the end of this docu ment. <br />6.3.1.2 Groundwater Modeling <br />Groundwater modeling results indicated there would be minimal volumes of groundwater flow into <br />the pit during mining operations (BC 2023b, Appendix 3.7). Groundwater flow entering the open pit <br />is estimated to be highest during the mine years 20 to 30 at approximately 45 gallons per minute <br />(gpm) based on the modeled groundwater elevation and the projected bottom of the open pit in the <br />MODFLOW model (Table 6-2). Groundwater flow rates into the sandstone pits during the 0 to 10 and <br />10-20 mine years is higher than the flow rates predicted for the other portions of the open pit. <br />Estimated rates of groundwater flow into the open pit decrease to a de minimums value (Table 6-2), <br />estimated to be zero flow, as the mine operations move eastward based on the interpolated water <br />table being lower in elevation than the bottom of the projected mine pit in the MODFLOW model. <br />Table 6-2. RCQ Groundwater Rates Model Results <br />Mine Plan (years) Rate of Groundwater Entering Pit (gpm) <br />0 to 10 2.29 <br />0 to 10 deep sandstone 6.89 <br />10 to 20 0 <br />10 to 20 deep sandstone 16.28 <br />20 to 30 45.41 <br />30 to 40 0 <br />40 to 50 0 <br />50 to 60 0 <br />60 to 70 0 <br />70 to 80 0 <br />80 to 90 0 <br />90 to 100 0 <br /> <br />The groundwater model predicted minimal impacts to the flow in Red Creek during the life of the <br />RCQ mining operations compared to the existing conditions predictions of stream flow (BC 2023b, <br />Appendix 3.7). Predictions of flow simulated during miner operations showed only a slight decrease <br />in the flow rate in Red Creek over the span of the mining operations. The groundwater modeling <br />results indicate the portions of Red Creek that currently have surface water flow would not become <br />dry as a result of the mining operations. <br />6.4 Surface Water Flow <br />Flow rates calculated using the corrected transducer data were plotted along with the daily <br />precipitation totals downloaded from the K1V6 weather station (Figure 6-12). Storm events in central <br />Colorado can be localized and produce heavy downpours over short timeframes. Storm events could <br />produce higher precipitation at the Fremont County airport than observed within the Red Creek <br />drainage and vice versa. However, the K1V6 weather station data is analogous to the storm patterns <br />observed within the region with winter 2022 through summer 2023 having above normal <br />precipitation amounts in Colorado. <br />Although there is not a direct correlation between flow rates and precipitation, several of the storm <br />events observed at the Fremont County airport correspond closely to increased flow observed by the <br />flume transducer. The overall pattern of an increase in storm events beginning in the spring of 2023