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Mathews Page 3 November 13, 2000 Hydrologic Soil Group, Hydrologic Condition, and Cover Type. li. Please provide justification and/or the assumptions used in selecting the C and P factors utilized in each of the SEDCAD runs provided for the Railroad Loop Area. This should include a description of the soil condition and support practices to be used. lj. SEDCAD Area 5 is the only area where a silt fence was utilized in the SEDCAD run for providing sediment control. SEDCAD runs for Areas 1-4 and 6-14 provide no sediment control stntcture. Please provide an explanation for the lack of sediment control at these areas and submit appropriate designs to treat the runoff from the Railroad Loop Area. 2. Map 155 was not adequately revised to show proposed sediment control. As indicated above, a silt fence was proposed for SEDCAD Area 5 only. Please revise Map 155 to show appropriate sediment control. 3. On Map 89 submitted with the original TR-51 application, silt fence was proposed for the entire length of the toe of reclamation. The revised Map 89 shows proposed silt fence locations for selected SEDCAD areas only. From the new design it appears that there will be mixing of untreated disturbed site drainage with undisturbed upland flow. The proposed plan as shown on Map 89 does not appear to provide adequate treatment for the combined flows from the following Areas: (1B, 13B, 6), (2,8, 8A), (3,9,10), (4,11), and (5,12). The new silt fence locations appear to contain only a portion of the runoff from SEDCAD Areas 6, 8A, 10, 11, and 12. A single silt fence is proposed for the combined flows from each of these SEDCAD areas. Please provide berm locations or other designs to show that the combined Flows from each SEDCAD area will be directed to and adequately treated by the proposed silt fence locations. No silt fence is shown for SEDCAD Area 7 on Map 89. The silt fence lengths shown on Map 89 for combined Areas (2, 8, 8A) and (4,11) do not correspond with the width along contour information contained in the SEDCAD demonstrations. Please clarify these discrepancies and provide revised silt fence designs that clearly show treatment will be provided for each designated SEDCAD area in its entirety. 4. See Comment 2 above regarding proposed sediment control for the Railroad Loop Area. 5. See comment 3 above regarding proposed sediment control for the East Portal Area. 6. The Division notes that silt fence weirs are not proposed for the East Portal Area. Are silt fence weirs proposed for the Railroad Loop Area? Also, see Comment ]j above. 7. Response accepted. It would be helpful to have the undisturbed drainage area topography also shown on Map 89 for SEDCAD Areas 1, lA, 1B, 2,3,4,and 5.