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Channel C is a trapezoidal channel with a 3-foot-wide bottom extending from the Detention <br /> Pond south 550-feet then changing to a "V" type channel with no bottom width. The channel <br /> is 1,473-feet long and ends near the top of the laydown area. <br /> Gabion drop structures will be installed for the length of the channel where the channel slope <br /> exceeds 6-percent. The average channel slope with gabions is at 6-percent. Fourteen (14)—3- <br /> foot-tall structures will be installed 91-feet from each other. <br /> Channel C: Onsite Stormwater Diversion Channel discharges into a detention pond. Target <br /> release rates from the pond were reduced by the increase in flows from Basins B, C, and F. <br /> Other basins are from undeveloped areas and flows rates will not change pre and post <br /> development. A 24-inch CMP pipe placed at the pond floor will extend through the bank, allow <br /> the pond to drain and release rates below 10 and 100-year historical flows. <br /> The maximum pond drain time is about 8-hours as shown in Appendix B. <br /> Surface Water Diversion Channels <br /> Culvert Studio modeling software was utilized to size the diversion channels to effectively <br /> transport the discharge from the respective precipitation events. Channels were designed to <br /> limit the Froude number to less than 0.8. Three (3)-foot tall gabion and grouted riprap <br /> structures are necessary for steeper channel sections to dissipate energy. <br /> Surface water channels will be lined with 12-inch diameter riprap to minimize erosion and <br /> dissipate energy. Channel dimensions and calculated Froude numbers are indicated in Table 4. <br /> Channel slope will be reduced to 6-percent where the Froude number exceeds 0.80 by installing <br /> 3-foot-tall, grouted rip-rap structures in the Offsite Stormwater Diversion Channel and rock <br /> gabion structures in the Contact Pond Channel and Onsite Water Diversion Channel. <br /> Model Channels A and B profiles and calculations are included in Appendix B. <br /> N <br /> N <br /> O <br /> N <br /> 00 <br /> N <br /> c-I <br />