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The following table describes the underlying filter material that will be used for each <br />section. The design of this material is based on studies done at Colorado State University <br />and presented in Design Hydrology and Sedimentology for Small Catchments. <br />• <br />During the excavation, areas of large rock or actual bedrock may be encountered. When <br />this occurs, filter material may not be used. If bedrock is substantial, the riprap lining <br />may also be eliminated. For the filter material design, it is assumed that the base material <br />will have D50 of 2 ". The area of the channel construction is generally rocky in nature. <br />Segment <br /># <br />Riprap <br />D50 (ft) <br />Riprap Thickness <br />Range (ft) <br />Filter Material <br />D50 (ft) <br />Filter Material <br />Thickness (ft) <br />1 <br />1.75 <br />1.75 -2.50 <br />0.25 <br />0.25 -0.50 <br />2 <br />1.75 <br />1.75 -2.50 <br />0.25 <br />0.25 -0.50 <br />3 <br />1.75 <br />1.75 -2.50 <br />0.25 <br />0.25 -0.50 <br />4 <br />None <br />DNA <br />DNA <br />DNA <br />5 <br />2.50 <br />2.50 -3.50 <br />0.25 <br />0.25 -0.50 <br />6 <br />1.00 <br />1.00 -2.00 <br />0.25 <br />0.25 -0.50 <br />A filter material of 0.25 feet or 4" will work for all segments. <br />As shown on the Hydrology Map, the Carbon Junction Canyon will be restored in its <br />original channel for the majority of the length upstream from the permanent diversion. <br />For this area, no lining will be needed. However, two portions of the channel, one near <br />the upper end of the diversion, and the other near the lower sump, will need to be lined <br />with riprap of D50 of 1.5 feet. A layer of 1.5 feet to 2.5 feet will be placed in a channel <br />width of 14 feet. No underlying filter will be employed in these areas since the existing <br />material is rocky. The approximate lengths of the two upstream lined areas are 150 feet <br />and 350 feet. <br />Certification and Inspection <br />The designs for the various structures have been appropriately certified. The sediment <br />control system will be inspected during construction and certified by a registered <br />professional engineer as required. <br />Ditches, and ponds are inspected annually in accordance with Rule 4.05.9(13). After <br />significant precipitation events, ditches, channels, and ponds will be cleaned and repaired <br />as required. Hay bales and riprap are inspected periodically and repaired as required. <br />Abridged Permit Document 5 -16 Feb 2008 <br />