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questionable due to the adverse slope of an 18" ADS pipe that is connected to the orifice. In its <br />current configuration, the orifice has the capacity to divert approximately 4 -cfs from the Boxelder <br />Ditch. The diversion structure will require modification to make delivery of the desired 30 -cfs <br />possible. <br />Ditch West of I -25 <br />The ditch west of I -25 from the diversion structure downstream to the I -25 culvert was cleaned and <br />reconstructed by The Flatiron Companies in the fall of 2005. A typical cross section of the ditch <br />lateral west of I -25 is triangular with sideslopes between 1.5:1 and 2.5:1, and a varying depth that <br />averages approximately 2 -feet. However, some sections of the ditch have a flat or slightly adverse <br />longitudinal slope, such as the section that runs parallel to the Boxelder Ditch for approximately <br />540 -feet ( -0.07% slope). Therefore, the ditch west of I -25 will require grading and enlargement to <br />carry the full 30 -cfs. <br />I -25 Culvert <br />Currently, a 24 -inch CMP conveys water under I -25 to the east. It appears that the capacity of that <br />pipe, which is on a 0.2 percent slope, is 5.5 -cfs or one sixth of the required capacity. As a result, <br />this pipe will need to be replaced with a larger pipe as well. A hydraulic analysis of the culvert <br />determined that a 42 -inch diameter pipe would be necessary to carry the 30 -cfs required. It is <br />proposed to use a 48 inch Hobas pipe as a casing to bore under I -25. This would allow future <br />capacity for a carrier to be pushed through the casing pipe. Bores under I -25 are common and it is <br />not anticipated that there should be any difficulty accomplishing this. A permit from CDOT will <br />be required. <br />Ditch East of I -25 <br />The I -25 culvert terminates in a ditch on the east side of the highway, which terminates at a splitter <br />box near the northwest corner of the reservoir. Current capacity of the subject ditch is <br />approximately 11 -cfs and therefore not adequate for the Augmentation Company's demands. The <br />splitter box appears to divide the flow between a mostly removed channel that used to flow south <br />across the reservoir property and a roughly visible channel that appears to go to the River. This <br />project proposes to remove the splitter box and grade a channel to inlet to the Timnath Flatiron <br />Reservoir. <br />Project Impacts <br />This project is not anticipated to have any negative impacts to the area. The project allows for the <br />efficient utilization of the Box Elder water rights and resources. It also will enhance wildlife <br />habitat by providing another location for waterfowl to roost. The reservoir will also function as an <br />aesthetic amenity to the entrance of the Town of Timnath. Another impact of the ;project is that the <br />layout of the reservoir preserves a significant section of river corridor for the Cache la Poudre <br />River in a rapidly urbanizing area. <br />7 <br />