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e. Side slopes generally of 4,1; acceptabie from 3:1 to 5:1, or more. f. CenterlIne curvature of twice the top width, but not less than 100 fee t. g. Freeborad of from one to two feet, e.~ept where overbank flow does not effect or calise damage. h. The channel bottom should be lined wIth rlprap to carry Ir- rigatIon releases from the Great Western Reservoir and Stand- ley Lake. I. The bottom of channel shall have a slope toward the trIckle channel. j. Froude number (turbulence factor) shall be less than 0.80. k. HydraulIcs roughness In accordance wIth the Denver Regional Council of Governments and other suitable criterIa. 1. Grass cover of crested wheat grass, or equal. 3. Rlprapped or Other Lined Channels. Higher velocity artlflcal channels wIll be used with discretIon, and the'n only to accomodate existing development for minimum re,aches. a. Rlprap size, design velocity and "n" valves to be based upon fIgures 19, 20, and 21 of the Bureau of Public Road publicatIon, "Des I gn of Roads I de Dra I nage 0 I tches" and the Denvel' Reg i ona I Council of Governments' criteria. b. Side slopes from 3:1 to 2:1 may be rlprapped, but steeper slopes must be solIdly lined with an anchored wall. The pre- ferable section for steeper 510110 slope's Is 0.5:1 wIth a re- taining wall structure embedded with natural stone. Care must be taken for freeze, thaw, 9rourdwater, and expans Ive soJ 1 effects. c. The bottom of channels must generally be lIned when el ther the velocIty exceed eight fps or the Froude number exceeds 0.8. d. Use trickle channels for low flows with capacities of about one percent of design flow, but not to exceed 250 cfs. Rlprap, concrete, or other protection to prevent erosion 15 needed. Vi -,3