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embankment with properly placed boulder fill materials. This alternative should not comprise the ditch integrity and would allow the original ditch to be used after the hillside has been stabilized. The second alternative would be to remove all of the failed/redeposited soils located within the failed area, as well as remove the fill materials that were placed over the natural hillside above and next to the failed azea. If this alternative is opted for, the irrigation ditch in the area of the slide and wherever the fill materials have been removed will have to be abandoned and a pipeline will need be constructed to convey the water flows across this area. In addition, a majority of the existing road/berm will probably be removed as the fill materials aze removed. If the first alternative is opted for, we would recommend that natural hillside and existing fill embankment be reconstructed by placing boulder fill materials in the failed areas after all of the mud and debris have been removed. Based on our limited observations, it appears that the toe of the boulder fill should start at a point located approximately'/~ way between the creek and the lower roadway failure. The boulders should be properly keyed benched at least 2 feet into the natural sands and gravels after all of the failed materials and natural topsoil materials aze removed. The boulder fill should then be constructed up the failed azea and to an elevation equal to the top of the berm that is located adjacent to the irrigation ditch. The outside face of the boulder fill materials should match the slope configuration of the surrounding natural hillside and/or previously placed fill materials. We recommend that durable boulders at least 2 to 3 feet in diameter be used in the boulder fill. We believe that the benefits of this alternative aze that the irrigation ditch and adjacent roadway can be used after the boulder fill materials have been properly placed; the seepage coming out of the failed azea will not have to be stopped, since the boulder fills will provide a stable and free draining buttress fill; and there appears to be an adequate source of boulders on the Elk Fork Ranch property to complete the boulder fill construction. One drawback to this alternative is that it will take time for the contractor to generate enough boulders to complete the boulder fill and time is of the essence with regards to turning the ditch back on. If the second alternative is opted for and a pipeline is constructed in the ditch above the failed area, it is imperative that the pipeline be of sufficient size to handle the maximum adjudicated flow, as well as the additional flows that could occur due to a large storm event. The sizing of this pipe is beyond our scope of work and expertise. However, we recommend that the pipe be properly keyed into the natural soils and bedrock materials that are exposed on the uphill side of the irrigation ditch. In addition, the pipe should be protected from rock fall damage by placing at least 2 feet of soil cover over the top of the pipe. The pipeline will have to extend far enough upstream and downstream of the failed area to cutoff and stop the seepage that is occurring in the failed area. It must be noted that this alternative will not be effective if the seepage is not stopped since fwther slope failures could occur if the seepage is allowed to saturate the topsoil and fill materials that aze situated both upstream and downstream of the failed azea. The fill materials above and along the sides of the failed area will have to be removed and,'or laid back to a more stable configuration. We would recommend that the fill materials be laid back to a 2 (Horizontal) : 1 (Vertical) or flatter slope configuration. lh addition, all of the disturbed soils must be removed from the failed azea, as wells as below the failed area. After the disturbed soils are removed, we recommend that the disturbed areas be covered with a layer of boulders (rip-rap) to help prevent further erosion in and below • Job Number. 03-5547 NWCC, inc. Page 4