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•- - Map 146 relates to the Road Base Storage Area. This map is being deleted and replaced with a similaz figure [o accompany the SedCad demonstration in Illustration 44. The SAE for [he Road Base Storage Area (see Ill. 44) was reviewed and found in error. Overly conservative estimates were used in determining sediment generation from this site. First, the SedCad model did not differentiate the CN (curve number) between the gravel pad and the stockpile. The proper CN for the stockpile would be sufficiently low that no runoff would be generated from a ] 0 yeaz-24 hour event. Therefore, the worst case runoff volume scenario would occur when no stockpile is in place. Secondly, no credit was taken for the presence of the gravel on the pad area. Placement of this cover material would dramatically lower the C factor. An appropriate value for this variable was obtained from OSM's "Guidelines for the Use of the Revised Universal Soil Loss Equation (RUBLE) Version 1.06...". Appropriate changes were made to the SedCad model to incorporate these changes, The revised SedCad output with associated figure are enclosed which represent these changes. 4.) Map 147 is being revised to include all small area exemptions. The required documentation to start the revision was just recently received from Western Fuels Association. This map is being revised into an electronic format to facilitate completeness and accuracy. A finalized version will accompany our second submission. 5.} Appropriate SAE designs and demonstrations for the three remaining "road blisters" are attached. These designs and demonstrations are intended for inclusion in Illustration 44. The upper four blisters will be designated as SAE's on Map 147. 6,) Following a review of the pad design it was found that the existing sediment controls meet or exceed that required for this area as explained in #3 above. The appropriate design and demonstration are enclosed for revision of Illustration 44. Map 146 has been replaced with a similar drawing that now accompanies [he SedCad demonstration in Illustration 44. 7.) SedCad designs and demonstrations aze being completed for these areas and will be included with the second submittal. 8.) Appropriate demonstrations, designs, and modifications to Map 1 ]2 addressing the runoff and sediment control for the north slope of Slot Storage will be included in the next submittal. 9.) Map 114 has been revised to delete the table concerning sediment pond dimensions for topsoil piles (see attached). 10.) Map 136 has been revised to reflect current conditions. 1 1.) a.) The current copy of the design and demonstration associated with "SDH #4, V Ditch and Culverts" is enclosed. This design and demonstration was submitted and subsequently approved in 1993. A copy is attached for inclusion in Illustration 44. b.) This issue was previously discussed and appropriate documentation attached. c.) The two sediment traps have been excavated to a volume greater than 0.029 ac.ft. each. Since this site will be reclaimed in the spring of 2001 no additional clarification is necessary.