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. AUTOMATIC COMPUTATION OF STAGE-DISCHARGE RELATIONS AT CULVERTS 21 -- . ONLY ONE TAILWATER ELEVATION SHOULD BE GREATER THAN OR EQUAL TO BASE ELEV, + D. HP-x IS NOT IN INCREASING ORDER. HP-4 SHOULD BE GREATER THAN OR EQUAL TO 1.5*0+ Z ELEV. H5-x IS NOT IN ASCENDING ORDER. H5-1 SHOULb BE LESS THAN OR EQUAL TO 1. 5*D + Z ELEV, H5-4 SHOULD BE GREATER THAN OR EQUAL TO 5.0*0 + Z ELEV. , TC SHOULD BE 1, 2, or 3. Z ELEV. SHOULD BE GREATER THAN OR EQUAL TO WOo B SHOULD BE GREATER THAN 0... . . Explanation: Refers to widthb on card 9. N SHOULD BE GREATER THAN O. L SHOULD BE GREATER THAN O. KT, KW. KR. AND CB12 SHOULD BE POSITIVE FOR TC=2. KT, KW, KR, AND CB12 SHOULD BE ZERO FOR TC=1 OR TC=3. CAL SHOULD BE 0 OR 1. Computational Messages The third category of messages is gener- ated during the computational phase of the program, and usually describes why no solu- tion is obtained for the stage-discharge re- lation. DISCHARGE NOT IN THE RANGE OF CRITICAL DISCHARGES... Q = qqqqq. qq. . . . . Explanation: The discharge shown is less than the critical discharge, Q , at the lowest c water- surface elevation. W . at the approach o section. The next discharge is then tried. If a solution is desired for the rejected Q, then W should be lowered. o qqqqq. q NO SOLUTION TYPE ONE FLOW. .. .. Explanation: Headwater ele- vation, HI, is greater than 1.5 0 + z for the discharge shown. qqqqq. q NO SOLUTION TYPE ONE FLOWnSUPERCRITICAL FLOW AT AP- PROACH SECTION..... Explanation: Head- water elevation. HI, is less than the ele- vation for critical discharge, or neither type 1 nor type 5 flow can occur at the discharge shown. qqqqq.q TYPE 2 ENERGY EQUATIONS NOT BALANCED..... Explanation: Type 2 flow cannot occur at the discharge shown. qqqqq. q NO SOLUTION TYPE TWO FLOW--SUPERCRITICAL FLOW AT AP- PROACH SECTION.".. Explanation: The area of the approach section at the elevation of d2 + z is zero, or the discharge shown is greater than- critical discharge at the com- puted headwater elevation. qqqqq. q NO SOLUTION TYPE FIVE FLOW..... Explanation: Type 5 flow does not occur' betw-een headwater elevations at 1. 5 D + z and 5. 00 + z, for the discharge shown. qqqqq. q NO SOLUTION TYPE THREE FLOW. . . .. Explanation: Type 3 flow does not occur between headwater elevations at d2 + z and 1. 5 0 + z for the discharge shown. The tailwater elevation will be printed. qqqqq. q TYPE 5 H NOT IN THE RANGE OF H5,.... H= hhh. hhhh..... Ex- planation: This is a warning that for the dis- charge shown. the indicated trial headwater elevation is less than H5-1 or greater than H5-4, as they are listed on card 8. A type 5 solution is then printed using a discharge coefficient equal to C5-1 or C5-4. TYPE X CANNOT INTERPOLATE COEFFICIENT--HEIGHT = hhhhh.hhhh..... Explanation: The trial headwater elevCltion shown is less than HP-l or greater than HP-4 on card 7. No solution is possible. so the next discharge is tried. TYPE X CANNOT INTERPOLATE CONVEY ANCE-- HEIGHT = hhhhh. hhhh. . . . . Explanation: The trial headwater elevation shown is outside the range of elevations at the approach section. If flow is type 1. the next discharge is tried. For type 2 flow, the message, "NO SOLUTION TYPE TWO FLOW --SUPERCRITICAL FLOW AT APPROACH SECTION:' is printed. If flow is type 3, the next tailwater elevation is tried.