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map shows regrading of the laydown area and the area east and north of the laydown area <br />when the other two maps show that no grading will occur in those areas? <br />13. In the TR-60 Sedcad designs for the ditches and for the Bear Creek culvert, the horizontal <br />distances used in deriving the time of concentration values for each subwatershed appear <br />to be considerably longer than the hydrologic flow path length of their corresponding <br />subwatersheds. For instance, in the Sedcad runs for ditch BCCD-2 and the side postmine <br />channel, the total horizontal distance used for subwatershed area I amounts to 24,770 <br />feet, even though the drainage area amounts to only 53.1 acres and, referring to Map <br />2.05-El-BCA2, the longest hydrologic flow path appears to be no more than 3,500 feet. <br />In another example, for the Bear Creek culvert, the horizontal distances given for <br />subwatershed area 1 add up to 41,383 feet. However, referring to Map 2.05-El-BCA2 <br />again, the longest hydrologic flow path for the drainage area appears to be less than <br />30, 000 feet in length. Please explain. <br />The Division has no further concerns. The time of concentration values used in the <br />Sedcad designs for ditches BCCD-1 and BCCD-2 and for the Bear Creek culvert BCC-1 <br />were revised in the November 26, 2008 submittal. <br />14. The summary sheet for the laydown area lists the disturbed area as being 0.13 acres in <br />size. The Sedcad design for the laydown area lists the area to be 0.4 acres. However, <br />referring to Map 2.05-El-BCA2, the runoff area appears to be much larger since there is <br />no upland diversion ditch for the laydown area. Please explain or revise the Sedcad <br />designs and text for the laydown area accordingly. <br />The Division has no further concerns. In the November 26, 2008 Sedcad design <br />submittal, Oxbow revised the acreage for the laydown area and for the watershed area <br />that is upgradient of the laydown area. <br />15. The Sedcad designs use a permissivity, or flow rate, value of 14 gal/min/ftz for straw <br />bales. As had been discussed previously in Minor Revision No. 64 back in 2002, the <br />Division and Oxbow's consultant disagreed as to the authenticity of that value. Although <br />the value appears in a published work, the value was corrected in a later publication by <br />two of the three original authors. The Division agreed to the use of the value in MR-64 <br />with a disclaimer added to the permit text. Please either justify Oxbow's position in using <br />this value, revise the straw bale permisssivity value accordingly in the Secad designs and <br />text or omit from TR-60 the proposed use of straw bales as sediment control. <br />Permit text associated with the Sedcad designs state that a permissivity value of 5.6 <br />gpm/ftzwas used in the designs. However, as stated in comment number 7A above, the <br />Division is not clear if that value was actually used in the Sedcad designs. <br />16. In the last paragraph on revised page 2.05-37, it is stated that small area exemptions are <br />identified on Map 2.05-M4. Please add to that sentence that small area exemptions for <br />the Bear Creekfan site are identified on Map 2.05-El-BCA2. <br />5