_GENERAL DOCUMENTS - C1981017 (320)

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Attachment A COAL BASIN/MINE BENCH 0UTSLOPE SEDIIIIENT CONTROL PROJECT 2.0 STATEMENT OF NEED 2.1 Coal Creek is listed on the 1998 303d list and thus qualifies for funding. The Coal Basin Mine was a complex of five coal mines located at elevation 10,000 feet in western Pitkin County. During construction and operation of the mines, the sedimentary shales and sandstones which overlie the coal seams were excavated and pushed over the steep ridge lines within which the mines had been developed, creating the mine bench outslopes. During operations, snow removal and other construction-related activities further impacted the slopes. These outslopes approach angle of repose, are virtually devoid of vegetation, vary in extent from three tenths to over eight acres each, and have slope lengths which approach 900 feet in some cases. The fine grained, down cast sandstone and shale materials are easily transported off the steep outslopes by snowmelt and runoff from rain fall. The results of the erosive processes are heavily gullied slopes and an elevated sediment contribution to Coal and Dutch Creeks. Due in large part to its unique geologic characteristics, the major drainages within Coal Basin transport a large volume of sediment annually. Observation of the gullied nature of the outslopes indicates that these features have added substantial volumes of sediment to the adjacent creeks, and to the Crystal River, approximately nine miles below the Project Area. Uses of Coal and Dutch Creeks are potentially impacted by the increased sediment contribution associated with the outslopes. A study conducted by the U. S. Forest Service in the 1970s indicates that elevated sediment concentrations found in Dutch Creek were attributable to mining operations. The report stated that observation indicated that mining-related activities, including the outslopes, contributed to increased sediment generation within the Basin. The report indicated that no single source of sediment contribution could be identified, however, the impact was attributed to many non- point sources directly related to the outslopes and to the mine roads,which are being reclaimed by Minerals and Geology. A study conducted by the U. S. Forest Service and others in the early 1990's suggests that the sediment load within these creeks is detrimental to macroinvertebrate species populations. A loss of macroinvertebrate species, in turn, will impact local fisheries. The Coal Basin/Mine Bench Outslope Sediment Control Project will compliment ongoing reclamation activities currently being undertaken by the Colorado Division of Minerals and Geology. Reclamation activities have been focused on minimizing sediment generation from mining-related disturbances. Over one hundred fifty acres have been reclaimed in Coal Basin during the last three construction seasons. Coal refuse piles, roads and mine entry areas have all been subject to reclamation activities since 1995.