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<br />Required concentration to increase stream flow concentrations by 45 mg/1: <br />522,377 mg 20,490 mg/1 <br />25.5 1 <br />Using the techniques outlined in Chapter V of the DEPOSITS design manual, the <br />basins' spillways were designed to provide 24-hour detention time. Such a <br />detention time would provide effluent qualities considerably lower than <br />20,490 mg/l, and therefore it can be concluded that any effects on Plorth <br />Thompson Creek would be imperceptible due to dilution and the small flow rates <br />of any discharges. <br />Impacts to water quality from total dissolved solids (TDS) can not be quantified <br />using a computer model. However, impacts would he minimal. Water quality data <br />shows runoff that has a pH which is neutral to slighltly basic. This water will <br />• not readily bring dissolved constituents into solution, raising the TDS. <br />As stated in the suspended solids discussion, North Thompson Creek will have a <br />flow of 409 cfs. Since TDS is inversely proportional related to flow, TDS v,ill <br />be very diluted at this time. An incoming flow of 0.90 cfs will not be large <br />enough to significantly increase TDS. Colorado Department of Health's <br />Classification and Numeric Standards, Upper Colorado River Basin and North <br />Platte River states no limit for TDS, nor does Snowmass' NPDES permit limit TUS. <br />Refuse Disposal Site Sediment Control <br />Runoff from the undisturbed area above the refuse disposal site will be diverted <br />away from the site. These diversions are designed to safely pass the runoff <br />from a 100-year, 24-hour precipitation event. Calculations and design criteria <br />for this area are included in the final design section of Appendix 4-B. <br />Runoff from the refuse disposal pile will be diverted to a sedimentation pond at <br />• the toe of the pile. This pond is shown on Drawing D-4-9. <br />4-107 <br />