Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />Hm = 0.5 + f (1.6) <br />g <br />,.rere Hm = freeboard height (ft) <br />V = average chmme1 velocity (ips) 2 <br />g = acceleratim of gravity = 32.2 ft/ret:. <br /> <br />tile mininun freeboard SIall be me foot. <br /> <br />d. Bottan Width. Bottan width SIall be determined using al1.owble <br />velocity, depth, limitatim, and selected side slope. <br /> <br />e. Slope of Ommel. Grass-1ined channels rmmilly will have slopes of 0.2 to 0.6 <br />percent. ,.rere the natural topogra!t1y is steeper than desirable. drops DBY have to be <br />nt";1;.,.Pd. <br /> <br />f. Curvature . Generally, tile center lire curvature shoold not have a radius less than <br />tw.i.ce the design flow top width, but not less than 100 feet. <br /> <br />g. resign Velocity. tile IlIlXinun velocity far the IlBjar storm design runoff SIall not <br />exceed five feet fps far gra&9-1ined channels. Mininun velocities for all channels <br />SIall not be less than two fps far tIE initial stann runoff due to -'i IIFntatim <br />coosideratims. <br /> <br />h. Roughness Coefficient (n). tIE values far limning's "n" SIall not <br />be less than those specified in Table 1.3. <br /> <br />i. Frosim. All channels shall be designed with the proper and adequate erosion control <br />features. <br /> <br />j. lIBter Surface Profile. A water surface profile far tIE DB jar storm runoff SIall be <br />cauputed far all channels and clearly sOOwn on tile final drawings subnitted far <br />approval. Canputations of tIE water surface profile sIxlu1d utilize standard 00ckwater <br />oetrods, taking into consi.deratim all losses due to velocity changes, drops, bridge <br />and culvert openings, and other o1stru::ti.a1s. Canputatims SIall be subnitted with tIE <br />final design plan. whether or not tIE energy gradient line is sOOwn on tile final <br />drawings is optional. <br /> <br />3.7 JrrI gI*i..... llI.tches <br /> <br />Irrigation ditches shall not be used to transnit stann runoff unless SlJ:h use is shown to <br />be without hazard substantiated by thorough hydraulic engineering analysis. Such analysis SIall <br />inclooe investigation of required ditch flow and existing water rights below tIE design point. <br />A Certification of lIBter Rights and a letter of autmrizaticn, signed and dated by an authoriz.ed <br />officer ar representative of the owner of tIE ditch, shall be subnitted far any ccntaIlplated use <br />of DDdification of irrigation ditcffis far stonn runoff. <br /> <br />3.8 Stmm Se.e's and Stmm Inlets <br /> <br />The term storm sewers systens refers to tIE system of inlets, ccnduits, oanholes, and other <br />apjmtenances which are designed to collect any convey initial stonn runoff to a point of <br />discharge into tile outfall drainage system. Storm sewers are a porti.cn of the initial drainage <br />systan which also inclooes street gutters, roadside drainage ditcffis, culverts, sm11 open <br />channels, and any other feature designed to handle runoff fran tIE initial storm. Storm se.ers <br /> <br />8 <br />