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Section 816.42 <br />(f) Diversion design shall incorporate the following: <br />(1) Channel lining shall be designed using standard engineering practices <br />to pass safely the design velocities. Riprap shall comply with the <br />requirements of Section 816.72 (b)(5), except for sand and gravel. <br />(2) Freeboard shall be no less than 0.3 feet. Protection shall be <br />provided for transition of flows and for critical areas such as swales and <br />curves. Where the are protected is a critical area as determined by the <br />regulatory authority, the design freeboard may be increased. <br />(3) Energy dissipators shall be installed when necessary at discharge <br />points where diversions intersect with natural streams and exist velocity <br />of the diversion ditch flow is greater than that of the receiving stream. <br />(4) Excess excavated material not necessary for diversion channel <br />geometry or regrading of the channel shall be disposed of in accordance <br />with 30 CFR 816.71-816.74. <br />(5) Topsoil shall be handled in compliance with 30 CFR 816.21-816.25. <br />With minor exceptions, channel lining, riprap and energy dissipators <br />~ will not be necessary for the low-velocity design flows in the <br />planned temporary or permanent diversion structures. As documented <br />in Exhibit 42, Drainage and Sediment Control Plan, the design flow in <br />the temporary ditches is less than 5 cubic feet per second, except <br />for Ditch N2, which is a channel designed with riprap as an energy <br />dissipator, and ..which discharges.. into Williams Draw.. Energy,_ <br />dissipating devices are not proposed for any ditches with design <br />flows of less than 5 cfs. All temporary and permanent ditches will <br />be stabilized with vegetation. Topsoil will be handled in compliance <br />with part 816. The 0.3 foot freeboard criteria will be met for all <br />diversion structures as shown in figure 30, Permanent Diversion <br />816-41R Revised - January, 1991 <br />