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<br />Flood plain roughness factors (Manning's On") used in these <br /> <br />computations were selected based on field inspeci:ion of the actual <br /> <br /> <br />flood plain conditions. The roughness factors used in this study <br /> <br />are listed below: <br /> <br />Channel area n ,- 0.035 <br />Overbank area (fiHds) n - 0.030 <br />Developed overbank areas <br />(wi thin city): n .- 0.050 <br /> <br />A detailed description of the hydraulic analyses completed as <br />a part of this study is included in the TechnicaJ Addendum No.2, <br />on file with the Colorado Water Conservation Board. <br /> <br />FLOOD PLAIN DELINEATION <br /> <br />The flood profile elevations and flood plain limits shown in <br />this report can be easily transferred to field locations by simple <br />survey methods using the established monumentation or by scaling <br />from physical features shown on the map. <br />To determine the depth of flooding or the fIood plain limits <br />at any location in the field, the following procedure should be <br />used: <br /> <br />Locate the ground point at which the depth of flooding <br />or the flood plain limit is to be estabIished on the 1" <br />= 400' flooded area map. <br />Determine the elevation of the water surface at the se- <br />lected ground point from Table 2 by interpolating between <br />the water surface elevations given for 1:wo adjacent cross- <br />section reference points. <br />Using the closest monument for elevation control, determine <br />the water surface elevation at the ground point by stan- <br />dard labeling technique. The flood plain limit is estab- <br />lished where the water surface elevation intercepts ,the <br />ground surface. <br /> <br />-14- <br />