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Northern Colorado Water Conservancy District <br />11 TV e <br />220 Water Avenue • Berthoud, CO 80513 • 970532-7700 • fax 970532-0942 <br />August 25, 2008 <br />Mr. Patrick Fischer <br />Cemex <br />P.O. Box 529 <br />Lyons, Colorado 80540 <br />Dear Mr. Fischer: <br />RE: Repair of Boulder Feeder Canal <br />As per letter dated November 14, 2007, the Boulder Feeder Canal developed a significant <br />seepage area in the Cemex property near Lyons. Northern Water, in cooperation with Cemex, <br />repaired the seep area by removing the canal lining and replacing it with compacted clay <br />followed by a layer of sandstone rubble rock to act as rip rap to prevent erosion of the canal. This <br />work was completed by April 1, 2008. <br />The repair was performed on 1,100 feet of the canal. Approximately 6,500 cubic yards of <br />material was removed by excavation and placed to the side of the canal for later use by Cemex. <br />Approximately 5,200 cubic yards of sandy clay from the Cemex mine area in Dow Flats was <br />placed into the canal in 6-8 inch lifts and was compacted with a sheeps-foot vibrating compactor. <br />The entire canal prism was lined with clay in this manner, to a total thickness of two feet. <br />Finally, the entire canal prism was rip-rapped with angular sandstone rubble rock that was placed <br />and tamped down to reduce the roughness of the canal. Approximately 1,100 tons of rock were <br />placed in the canal. <br />As of August 2008, the seepage appears to have been successfully curtailed. <br />Sincerely,. <br />--f <br />Roge A. Sin en <br />Distribution Systems Department Manager <br />cps