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<br />rte. nuc~,nFr. sAVAC~ <br />Page 3 <br />January 7, 1981 <br />4. A berm will be constructed on both sides of the <br />rocklined outlet to prevent disturbed drainage fran entering <br />the ditch. The berm will be twv feet in height and have 2:1 <br />side slopes and will be revegetated with the same seed mixture <br />as the surrounding reclaimed surfaces. <br />5. Due to the nature of the material in which the ditches <br />will be constructed, platy rock fragments will be found the <br />entire length of the channel. Phis will occur as a result of <br />the dozer cutting the ditch through the material. The reader <br />is referred to the soil profiles for subsoil descriptions. <br />The range of sizes will be from 3" - 18". <br />6-8,10. See Darry's letter dated January 6, 1981 to Jim Kent. <br />9. The information concerning design r ~irements has <br />been provided in the amendment by the table giving the storage <br />requirement and the figure showing pond construction. TBM <br />would like to know what design criteria regulations Nff,R is <br />applying to the ponds. <br />11. Primary spillways will not be used to handle greater <br />than 10 year 24 hour storm events. <br />12. Culvert C-4 is cosr~prised of two five foot culverts <br />that have effectively passed discharge from spring runoff and <br />above normal storm events without problem. TBM believes these <br />are sufficient to satisfy the interim regulations. <br />13. Culvert C-6 <br />Peak discharge 6.54 cfs <br />Discharge Required - 6.54 cfs <br />Slope - 3 percent <br />Q = Conveyece <br />5 1/2 <br />6.54 cfs = 37.76 <br />1.732 <br />Go to Table 6 - Conveyance Factors for Fond Pipe and <br />it can be seen that the 18" culvert can safely pass this flow. <br />14. All pond designs relevant to the above discussions <br />were done by a registered professional engineer. Please refer <br />to any of the sediment control maps for Mr. Ferguson's P.E. Seal. <br />