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precipitation/snowmelteuents up to and including the 10-year, 24-hour precipitation event; and pH limit applies to precipitation/snowmelt events above a 10-year, 24-hour precipitation event. The only limit placed on Colowyo's entitlement to the Alternate Limitation is the Burden of Proof that the discharge or increase in discharge was caused by the applicable precipitation/snowmelt event. The storm exemption from TSS, total iron, and SS is available to Colowyo during precipitation/snowmelt events at Colowyo's option. The dischazges will normally occur through the "primary discharge", which in the case of these ponds will be the riser pipe. The riser pipe will have "weep" holes in the pipe at specific elevations. The elevation of the weep holes and/or top of the pipe is being determined by the SEDCAD model, based on agreed upon inputs with the CDMG, that attempt to reflect the conditions of the applicable watersheds. It is realized that the SECAD model is a predictive model and should be used as a tool in aiding with the design and construction and be predictive of the dischazges of the ponds. Ultimately, Colowyo's compliance with the WQCD's discharge permit conditions will be the analytical results of sampling of the dischazges. Each pond will have an "emergency spillway" that will be located at an elevation higher than the top of the riser pipe and below the crest of the impoundment. The "emergency spillway" will automatically come into use in the event the inflow to the pond exceeds the capacity of the primary discharge pipe, or under any other emergency conditions. The purpose of the emergency spillway is to preserve the integrity of the impoundment structure and prohibit the uncontrolled flow of water over the structure. The ponds will also be fitted with a manual dewatering device (headgate) located below the lowest weep hole. This will be used to drain the pond to enable maintenance work, which may include work to the impoundment structure, riser pipe, headgate, or for any other reason that lowering the elevation of the water in the impoundment becomes necessary. There may be occasions when typically, to facilitate pond maintenance, Colowyo needs to pump the remaining water out of the pond and into the receiving waters. As stated in the draft Industrial Dischazge Permit No. CO-0045161, dischazges from the manual dischazge system (headgate) will have to meet primary discharge standazds. Sampling of the dischazges from the ponds will be in accordance with the permit requirements. Dischazge limitations will also be in accordance with the permit requirements. In conclusion, with technical input from CDMG personnel, Colowyo is making significant progress towazds the completion of TR 41. Not only will the sedimentation ponds be re-designed but designs for permanent surface drainage structures will also be confirmed and new pond as-built drawings will be prepazed. T1tis requires extensive work which is scheduled for completion in Mazch, 1998. 3