Laserfiche WebLink
---- ~ - - <br />rug. ruclv+cl, snvACr. <br />Page 3 <br />January 7, 1981. <br /> <br />4. A berm will be constructed on both sides of the <br />rocklined cutlet to prevent disturbed drainage from entering <br />the ditch. 'I7ie berm will be twn Peet in height aril have 2:1 <br />side slopes and will 1~ reveyetatecl with tho same seed mixture <br />as the surrounding reclaimed surfaces. <br />5. Cue 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. This 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 requirements has <br />been provided in the a~rndment by t11e table giving the storage <br />requirement and the Figure sha.~ing pond construction. TB.M <br />~~ould like to know what design criteria regulations [f¢,R is <br />applying to the ponds. <br />11. Prirury spillways will not he used to handle greater <br />than 1.0 year 24 hour storm events. <br />12. Calvert L-4 is comprised of two five foot culverts <br />that have effectively passed discharge fran spring runoff and <br />above normal storm even is without problem. T'I3M believes these <br />are sufficient to satisfy the interim regulations. <br />13. Culvert C-6 <br />Peak discharge 6.54 cfs <br />Di sctrarye Pccluired - 6.59 cfs <br />slope - 3 perc~r~rt <br />= Conveyence <br />5 1%2 <br />6.59 cfs = 37.76 <br />1.732 <br /> <br />Co to Table 6 - Conveyance Factors for Pond 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 t3ie sediment control maps for Mr. Ferguson's P.E. seal. <br />