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January 2002 Sexero IIIP/Soxtb E.xPannon * Drainage and Sediment ConfrolPlan • Page 8 5.0 HAUL ROAD CHANNEL AND CULVERT DESIGNS All haul road ditches were designed to safely pass the peak discharge from the 10-year, 24-hour event. The ditch dimensions were detemvned using Mannings Equation for open channel flow. All road side ditches will be gravel lined. All road side ditch inputs and results can be found in Appendix 2, Haul Road Channel and Culvert Designs. The design results and ditch locations are shown on Exhibits 13- 21.1, 13-22.1, 13-23.1 and 13-24.1. As shown on the ditch results, the flow velocities for all the road side ditches aze less than 6 feet per second and will not require riprap. The culverts were designed to safely pass the peak dischazge from the 10-yeaz, 24-hour event. The culverts were sized using the U.S. Bureau of Public Roads nomograph. All culvert design inputs and results can be found in Appendix 2, Haul Road Channel and Culvert Designs. Haul Road J is designed as a relatively flat road and the location and length of road side channels and location of culverts is difficult to predict until the road is built. Given the difficulty to predict the location and length of the ditches, the ditches were conservatively designed to handle the peak dischazge from the entire watershed above Haul Road J. Culvert JI was also conservatively designed to handle the peak dischazge from the entire watershed above Haul Road J and Haul Road I. Culvert J- 2 was designed to pass the peak flow from the entire watershed above the Pond 016 system, assuming worst case disturbed conditions. Additional culverts may be required along Haul Road J. These additional Culverts were conservatively designed to handle the peak dischazge from the entire watershed above Haul Road J. • PR-OS Revised Ol MWH * 165 S. Unian Boulevard, Suite 410 * Inkemood, Colorado 80228 * (970J 7635140