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EXHIBIT 3 REQUIRED CROSS SECTIONS FOR SPECIAL BRIDGE ROUTINE The cross sections below show the points required on cards GR when using the special bridge routine. Cross sections 1, 2, 5, 6 are taken in the river channel upstream and downstream from the bridge and should represent the full cross section unaffected by the bridge. C,r!>_ss .Jlection 3 is adja- cent to the bridge 011 the downstream side and includes the-'elevat1ons . - and stations of an artificial levee whose top is about-equal to the low cnora'elel1Ufon (ELLC). The pg:ints defining the artific1allevee-'l!!!l'I be-omitted if the elevations where the effective area changes are shown on the x:3 c~.rd(eighth and ninth fislds), thus cross section 3 could resemble cross sections 1 and 2. Cross section 4 is adjacent to the hrLdgeon the upstream side and includes the elevation and station of an artificial levee (or an X3 card with elevations in eighth and ninth fields) whose top elevation is approximately equal to the top of roadway elevation (gLIRD). No cross section is provided through the bridge, but ~ describing the bridge are entered on cards SB, X2 and BT (optional). There- fore, when using the special bridge routine cross sections 3 and 4 should describe the channel cross section (excluding any roadway embankment) immediately downstream and upstream from the bridge. The t~tl'oadway embankment should be described on Clard X2. or liT. ELLC+ L/\J l " II II ,UI ~BWCtI Cross Section 3 Immediately downstream of bridge embankment ELTRD :! 1\ Lf ~J II II :u: ~BWC \" Cross Section 4 Immediately upstream of bridge embankmen Cross Sections 1, 2, 5, 6 Full natural river cross sections ,+ 6 3 4 -1 The artificial levees (or the elevations on the X3 card) are included in the cross section points in order to confine the flow to the chsnnel area when the water flows under the bridge low chord and to allow the use of the overbank flow area for flows over the road. The left and right bank stations must be equal to stations at the top of the artificial levees. Variable lEARA on card X3 must equal 10 for this condition. Exhibit 3