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permit area, to the extent possible, using the best technology currently available. <br />Appropriate sediment control measures for these diversions may include, but not be <br />limited to, maintenance of appropriate gradients, channel lining, revegetation, <br />roughness structures, and detention basins. No diversion will be located so as to <br />increase the potential for landslides. When no longer needed, each temporary diversion <br />will be removed and the affected land regraded, topsoiled, and revegetated in <br />accordance with 4.06, 4.14, and 4.15. If the temporary diversion was for an ephemeral <br />stream, the channel will be reestablished to functionally blend with the undisturbed <br />drainage above and below the area to be reclaimed. Diversion design will incorporate <br />the following: <br />(a) Most ditches will not need to be lined, however, any stretch of collection <br />ditch which has a velocity above 5.5 feet per second will be lined. Channel <br />linings, including channel riprap, will be designed using standard <br />engineering practices to pass safely the design velocities. These velocities <br />assume the typical silty loam soil conditions on site. If better conditions <br />exist, the velocities will be allowed to increase without lining. If worse <br />conditions exist, lining may be needed for lower velocities. <br />(b) Freeboard will be a minimum of 1.0 feet. Protection will be provided for <br />transition of flows and for critical areas such as swales and curves when <br />excessive velocities are anticipated. <br />(c) Energy dissipators will be installed when necessary, such as at discharge <br />points, where diversions intersect with natural streams and exit velocity of <br />the diversion flow is greater than that of the receiving stream. <br />(d) Excess excavated material not necessary for diversion channel geometry <br />or regrading of the channel will be disposed of in accordance with 4.09. <br />(e) Topsoil will be handled in compliance with 4.06. <br />(f) All ditches, culverts and diversions will be temporary; therefore peak flows <br />will be designed for the 10 year 24 hour event of 2.0 inches. <br />Section 2.05.3(4) Page 3 November 2012 <br />-#c „?'d <br />