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<br />can be divided into a maximum of six seg- <br />ments representing different characteris- <br />tics. At least one segment must be a chan- <br />nel segment. The remainder can be chan- <br />nel, damage, or nondamage segments. The <br />segments must begin and end on points <br />that appear in the section table. <br />Manning's roughness coefficient 'n' can <br />be changed at user-specified values of <br />hydraulic radius. <br /> <br />Methodology <br /> <br />,Valley Section Analysis <br /> <br />The standard step method, with some <br />modifications, is used to compute profiles <br />between valley sections. All profiles are <br />computed in the upstream direction. There- <br />fore, only subcritical flow can be analyzed. <br />The letter 'C' appears on the output when <br />criticai or supercritical flow occurs (see <br />section 92100 of the sample output), <br />After defining a starting valley section, <br />the program can start computations from <br />given eievations, from given slopes, or if <br />no starting information is given, from criti- <br />cal depths. Ail profiles at a given beginning <br />point must be started in the same manner. <br />Once the downstream starting information <br />is developed, the following steps are <br />needed at the upstream section to extend <br />the profile upstream. <br />Step 1.-Determine a set of elevation <br />values at the upstream section correspond- <br />ing to the following depths: <br /> <br />0.0 <br />0.2 5.6 18.2 38.0 <br />0.4 6.4 19.6 40.0 <br />0.6 7.2 21.0 42.0 <br />0.8 8.0 22.4 44.0 <br />1.2 9.0 24.0 46.2 <br />1.6 10.0 25.6 48.4 <br />2.0 11.0 27.2 50.6 <br />2.4 12.0 28.8 52.8 <br />3.0 13.2 30.6 55.2 <br />3.6 14.4 32.4 57.6 <br />4.2 15.6 34.2 60.0 <br />4.8 16.8 36.0 62.4 <br /> <br />At anyone road restriction, WSP2 can <br />Compute head losses through one bridge <br />opening or up to five culvert openings with, <br />different configuration. Each of the five <br />culvert openings can have an unlimited <br />number of identical culverts. Although one <br />bridge opening along with several culvert <br />openings can be defined for one road re- <br />striction, the procedure has not yet been <br />fully developed. <br /> <br />The elevation table stops at the highest of <br />the two end points of the cross section. <br />WSP2 places a vertical side wall on the low <br />side to extend the lowest end point up to <br />the elevation of the highest end point. For <br />sections more than',62 feet deep, each of <br />the depths is doubled before computing <br />the elevations. <br />Step 2.-Compute area and conveyance <br />(KD) values for each segment for the ele- <br />vations chosen in step 1. The KD values for <br />flood-plain segments' are adjusted to reflect <br />their shorter reach length. This technique <br />is described in chapter 14 of NEH-4. For <br />any elevation, WSP2 interpolates or extrap- <br />olates area values on a linear basis and <br />KD values on a log basis. All extrapolations <br />are based on the last two tabulated points. <br />Step 3.-For each of the elevations <br />chosen in step 1, WSP2 computes and <br />saves critical discharge and velocity head. <br />Critical discharge i's computed using the <br />equation <br /> <br />Q= V 32.2 A' <br />. T <br /> <br />where A is the valley section area and T <br />is the top width. WSP2 computes the vel- <br />ocity head for an assumed slope of 0.0001 <br />ft/ft and weights the head by the percent- <br />age of flow in each segment. The velocity <br />head equals the velocity head for a seg- <br />ment times the percentage of total flow <br />flowing in that segment. The actual velocity <br />head for any assumed upstream elevation <br /> <br />2 <br />