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This storm was too much for the surface water system in place at the • time to handle. The publication Peak Flows in Colorado, indicates that the 24 hour 100 year storm for the area would be about 2.4 inches. Measurements of the rainfall amount at the mine were obtained with numerous catch buckets that had been placed around the site. The buckets are not precise but do give a good estimate of the actual precipitation on site. The runoff from the storm did significant damage to the mine facilities. Runoff seemed to be more akin to a mud slide than a rain fall. Trees, bushes and boulders were ripped from the stream channels and quickly became impediments to the water system. Nearly all culverts were plugged with a tree or boulder. Vegetation on the berms along the road indicated that the runoff near the second gate in the twenty-five foot wide road was over three feet deep. The sediment pond was completely filled and an unknown amount of water bypassed the controls. Water flowed over the top of the pond embankment for about two thirds of its length. The quality of the water discharged and the measures taken to notify the regulatory authority are detailed below in the surface water section. BFFKCT OF THB MINBS ON THB BAST SALT CRBBK RBGIMK Surface Water Due to the limited disturbance of the mines there is little chance • that any significant effect on the quantity or quality of the surface waters near either mine sites has occurred. As the Division notes in its approval package for the Munger Canyon Mine, the total area that will be disturbed by both mine sites amounts to 0.12 percent of the area of the Bast Salt Creek drainage basin above the mines. Surface water samples during the 1992 water year were taken on McClane Creek (SW-2 and SW-5), Munger Creek (SW-3), and Bast Salt Creek (SW-1 and SW-6) as required by the monitoring program. Results of the quarterly sampling for each of the monitoring sites are shown in Table 4. Both McClane and Munger Creeks were dry most of the year as is normal. Only during the third quarter were samples collected simultaneously for all sample points. A comparison of the parameters in McClane Creek and Bast Salt Creek shows no significant concentration changes between samples taken above and below the mine. No samples of the runoff from the July storm were obtained. Flow in the creeks had ceased by the time the storm was discovered some 10 hours later. A sample was collected from the discharge of the sediment pond though. The results of the sample and a letters to the Colorado Division of Health requesting that a storm exemption be granted are included as Appendix A. Phone conversations with the Department of Health have indicated that an exemption will be granted. To date no exemption has been received. • Page - 4 1/29/93