Laserfiche WebLink
~J <br />• <br />u <br />RSS Operational Drainage to Pond 9 <br />Calculation Rational and Results Summary <br />Rational: <br />- Calculated using Sedcad+ Ver, 3 <br />- Areas, slopes and flow paths digitized from 100 scale topo maps flown in 11/94. The <br />attached 400 scale diagram represents the subwatersheds digitized, <br />- The soil map, Exhibit 23, shows the area as Area 80 -"Stony Land" and Area 52C <br />"Utaline Stoney Loam. There is no defined soil group associated with the "stony <br />land" soil therefore Table 5.1 in the Sedcad reference manual was used to determine a <br />soil group. Generally the soil samples for this and other disturbance areas classifies <br />the soil to be sandy to silty loam (Tab Section 9) which equates to a "B" soil group. <br />Utaline has a published soil group of "B" in Table B-1 of Peak Flows in Colorado. A <br />"D" soil group was used for operations areas where clays from the mining operations <br />may be incorporated in the surface. The following CN's were used in the calculations: <br />64 - B soil group, sage-grass with 20% cover. <br />84 - B soil group, gravel road. Used for parking, storage and stockpile areas. <br />86 - B soil group, fallow, baze soil. Used for topsoil piles, ponds and dirt <br />slopes. <br />- 100 year 24 hour storm event of 2.2" used for drainage calculations associated with <br />RSRDA <br />Results Summary: (other information may have been generated in this section but is not being <br />used in the site drainage design at this time.) <br />Structure # Structure Description <br />111 Culvert for drainage above <br />RSRDA <br />12l Culvert from part of <br />storage azea <br />131 Culvert from part of <br />storage area <br />211 Combined top of RSRDA <br />drainage - ] ] 1+121+131 <br />221 South collection ditch <br />on RSRDA <br />Design <br />0.5% slope, 12" min, 24" in place <br />1%grade, 12" min., 8" in place (Excess flow will <br />be carried in 131 culvert, see Half of RSRDA <br />Storage Area culvert sizing) <br />1%grade, 6" min., 8" in place (see note for 121) <br />40%grade, 8" atin., 12" in place <br />1:1 side slopes, 1% grade, 1.1' min. depth <br />RSS-20 <br />(Rev. 12J16>tiJ6) <br />