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to quantify the operation of the culvert. The potentially Bost serious event would be if Che culvert becomes totally clogged, causing possible embankment failure. There is no eaact way to determine when or if these impacts will occur. Even though the stream has been dry in recent years, the risk factor for any basin for the occurrence of a 100-year storm event in a 100-year period is 63 percent. The risk factor for the occurrence of a 500-year storm event in 100 years ie 18 percent. The third potential surface water impact is possible damage to the water-supply pipeline for the City of Rockvale which crosses the haul road. Current engineering standards usually require a pipeline cover of 3.5 feet to insure protection against freezing, as a minimum. More cover may be required for live loading. All these potential impacts to the surface-valet system can be reduced to insignificant levels by using sound engineering design principles for the structures. 2.0 Ground Water Based on an analysis of local geology and peat mining impacts, ii seems unlikely that the quantity or quality of ground water in the project area will be adversely impacted. The two ground-water sources of greatest concern are the Oak Creek alluvium, which is a source of water for the town of Rockvale, and the Caldirola Mine yell which supplies water for the town of Coel Creek. Because the Oak Creek alluvium is not connected to the ground water in the project area, neither quality nor quantity of this source would be eapected to be impacted. The Caldirola Mine well lies updip on the east flank of the Chandler Syncline and ie thus unlikely to have its quality impacted. • There ie a possibility that the quantity at this well could be impacted if the aquifer drains ae a result of mining-induced JFSA-66