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The following table describes the underlying filter material that will be used for each section. The design of this material is based on studies done at Colorado State University and presented in Design Hydrology and Sedimentology for Small Catchments. During the excavation, areas of lazge rock or actual bedrock may be encountered. When this occurs, filter material may not be used. If bedrock is substantial, the riprap lining may also be eliminated. For the filter material design, it is assumed that the base material will have D50 of 2". The azea of the channel construction is generally rocky in nature. Segment # Riprap D50 (ft) Riprap Thickness Range (ft) Filter Material D50 (ft) Filter Material Thickness (ft) 1 1.75 1.75-2.50 0.25 0.25-0.50 2 1.75 1.75-2.50 0.25 0.25-0.50 3 1.75 1.75-2.50 0.25 0.25-0.50 4 None DNA DNA DNA 5 2.50 2.50-3.50 0.25 0.25-0.50 6 1.00 1.00-2.00 0.25 0.25-0.50 A filter material of 0.25 feet or 4" will work for all segments. As shown on the Hydrology Map, the Cazbon Junction Canyon will be restored in its original channel for the majority of the length upstream from the permanent diversion. For this azea, no lining will be needed. However, two portions of the channel, one near the upper end of the diversion, and the other neaz the lower sump, will need to be lined with riprap of D50 of 1.5 feet. A layer of 1.5 feet to 2.5 feet will be placed in a channel width of 14 feet. No underlying filter will be employed in these areas since the existing material is rocky. The approximate lengths of the two upstream lined azeas are 150 feet and 350 feet. Certification and Inspection The designs for the various structures have been appropriately certified. The sediment control system will be inspected during construction and certified by a registered professional engineer as required. TR08, TRl1(v1.0) 5-17 Revised 9/97, 08/02