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Mr. Kiger - 2 - September 3, 1986 ^ /c. Can you predict both peak and base spoils flow discharge volumes and vvv their accompanying hydrograph? d. Predict the consequences of spoils discharge water on surface water and alluvial water quality downstream. The spring and seep monitoring and mitigation plan needs further development. We have found that spoils springs have peak flows during high snowmelt periods, usually in April. As the peak discharge drops abruptly in May, we would like you to perform the spring and seep survey between April 1 and May 15. Should you have a number of large springs, we would like you to commit to quarterly full suite analyses and monthly field parameter monitoring of all springs with peak flows greater than 75 gpm, or an annual full suite analysis far the single largest spring should flows not be so high. Last, Colowyo should commit to submitting the data with a map locating the springs. The mitigation plan needs to be more detailed. It needs to outline specific standards which will be used to assess environmental harm, a time schedule for initiating the mitigation plan and finally, criteria which can be used to specify mitigation. In the past, the Division has ~ recommended that areas of topsoil contamination of spring flow volumes I could be used to evaluate potential environmental damage. Mitigation "~ time schedules should include time periods for re-submittal of design I / adequacy plans using peak spoils discharge contributions for the affected ditches and sediment ponds. Flow criteria and/or slope criteria should ~ be used to initiate the design of various types of drainage systems (i. e1 channels (triangular, trapezoidal, parabolic), rip-rap, french drains, etc.) ~• ~~~ Dn August 13, 1986, CMLRD performed a field inspection at H-G and during the inspection, recent tipple alluvial well water quality analyses were discussed. The down dip well at the tipple took over six weeks to recharge following baling. This is an unacceptable period of time and indicates that the well is inappropriately located and/or completed. As this has been a problem in the past, the Division demanded that the well be replaced to ensure appropriate water monitoring results. We would accept well development work as an alternative to re-drilling, should it increase the flow to permit same day baling and sampling. Additionally, the Division has been concerned about the location of the up-dip well for over a year. The up-dip well typically shows 2-3 times higher salt concentrations than the down-dip well. The Division has asserted that the well is either contaminated by coal fines leachate, it is located in a site (salt flat) incomparible with the down dip site, or it is improperly completed and contaminated by drilling mud. In any case, the well does not appear to be an appropriate up-dip, pre-disturbance site. The Division requests that the up-dip well be replaced at the same time that the down-dip well is replaced.