Full Equations (FEQ) Model for the Solution of the Full, Dynamic Equations of Motion for One-Dimensional Unsteady Flow in Open Channels and Through Control Structures
*WRN:01*
| EXTRAPOLATION NOT DONE. TOP WIDTH < 0. EXT = ff
| An extrapolation request for a cross section results in a negative top width. The extrapolation is not done. *WRN:02*
| X-SECTION BELOW RANGE IN XLOOKY | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff Depth input in subroutine XLOOKY is less than the minimum depth available in the cross section. This message is not issued if the CUTOFF option for cross sections has not been used. Use of the CUTOFF option defines an elevation in the cross-section table below which information in the cross-section table is discarded. If this warning is issued, the user should consider whether the CUTOFF option should be used. *WRN:03*
| X-SECTION ABOVE RANGE IN XLOOKY | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff Depth input in subroutine XLOOKY is greater than the maximum depth in the cross section. If this warning is issued only a few times and if the resulting maximum depth at the conclusion of the run is less than the maximum, no action is required. However, if the warning is issued many times and the run terminates prematurely or the maximum depth at the conclusion of the run is the same as the maximum depth in the cross section, then either the cross section must be extended by use of the EXT option or additional data must be obtained to further define the cross section and recompute the table with FEQUTL (Franz and Melching, 1997). *WRN:04* | HU > HMAX IN TWO-D TABLE# = nn HU = ff HMAX = ff | The upstream head for a two-dimensional table of Type = 6 is greater than the maximum upstream head stored in the table. The maximum stored upstream head is used and computations continue in FEQ. If this message is issued many times and if the limitation on maximum upstream head appears to have affected the flow, then the table must be extended so that the message no longer is issued. *WRN:05* | ABRUPT EXPANSION CANNOT ALLOW REVERSE FLOW AT TIME = ff WITH FLOW = ff
UPS NODE nn, AND DNS NODE nn | The current implementation for an abrupt expansion cannot allow reverse flow, but such a flow has been simulated. The flow is forced to be zero and computations continue in FEQ. *WRN:06* | INVALID CRITICAL DEPTH FACTOR AT UPS NODE = nn IN ABRUPT EXPANSION. | DEPTH = ff The computation of critical flow when the correction coefficient for momentum flux is included is not always possible. An invalid condition has been found at an upstream (UPS) node, but the computations will continue in FEQ if possible. This error will not result if the momentum-flux correction factor is a constant. *WRN:07* | INVALID CRITICAL DEPTH FACTOR AT DNS NODE = nn IN
ABRUPT EXPANSION. | DEPTH = ff The computation of critical flow when the correction coefficient for momentum flux is included is not always possible. An invalid condition has been found at a downstream (DNS) node, but the computations will continue in FEQ if possible. This error will not result if the momentum-flux correction factor is a constant. *WRN:08* | EXP-CON WITH FLOW NODE = nn CANNOT ALLOW REVERSE FLOW
AT TIME = ff WITH FLOW = ff AT UPS DEPTH = ff AND DNS DEPTH =
ff | The computed flow in an expansion-contraction indicates reversal when the physical conditions are such that a reversal is impossible. The reverse flow is forced to zero, and computations continue in FEQ. *WRN:09* | CONVEYANCE NONINCREASING AT DEPTH = ff | Conveyance should always be increasing with depth in an open channel with diverging walls. This message is issued if the drop in conveyance over the depth interval is less than 0.5 percent. *WRN:10* | CRIT. FLOW NONINCREASING AT DEPTH = ff | Critical flow, computed without reference to the momentum-flux correction factor, is decreasing with an increase in depth. Computational problems may result in the region of decrease. *WRN:11* | DROP OF ff PERCENT IN CONVEYANCE AT DEPTH = ff | Conveyance should always be increasing with depth in an open channel with diverging walls. This message is issued if the drop in conveyance is greater than 0.5 percent. Corrective action is to further subdivide the cross section so that the cross-section shape can be better represented by the hydraulic radius. *WRN:12* | BOTTOM ELEVATION DIFFERENCE BETWEEN NODE nn, aa, AND
NODE nn, aa, IS ff | The bottom-elevation difference may be correct but also may be the result of an error. If the difference is large enough relative to the flow, problems with critical or supercritical flow will result in simulation. This message also is issued in some cases when a branch discharges into a level-pool reservoir. In general, reservoirs are best represented such that the depth and the elevation of the water surface are the same. In simulation, the bottom of the reservoir is at the elevation datum, which is usually far below the bottom elevation of the branch. This warning is issued for each such case, but it can be ignored because the discontinuity in bottom elevation between a reservoir and a branch has a smaller effect than for a discontinuity in the bottom elevations at a junction among branches. *WRN:13* | ELEVATION RELATION PATTERN MAY CAUSE PROBLEMS.
RECAST SO THAT CODE 3 RELATIONS ARE ALL TIED TO A SINGLE NODE.
NODES AT JUNCTION ARE: nn | The pattern used for code 3 relations at a junction was previously given in round-robin style. For example, assume four nodes at a junction, nodes 3, 4, 6, and 9. Three elevation relations are needed to complete the junction specification. In FEQ versions prior to 7.0, the nodes would be paired as: 3 and 4, 4 and 6, and 6 and 9; that is, in a pattern that keeps the difference between node numbers as small as possible. This pattern is not efficient and should not be used because the matrix is not always successfully patterned in FEQ. The patterning of the matrix may fail, and a BUG message may be issued that no relation can be found to terminate a path at a node in a junction. The specified node number is in the junction in question. Limited experience has shown that the problem disappears if the relations including code 3 at a junction are rearranged so that all reference one node. In the current example, a valid pairing would be 3 and 4, 3 and 6, and 3 and 9. Any other node could be specified as the base node. This warning only arises if there are four or more nodes at a junction. If there are less than four nodes at a junction, the round-robin style and the one-node reference style are the same. *WRN:14* | HEAD DATUM= ff DISAGREES WITH TABLE#= nn HAVING HEAD
DATUM= ff | If a head datum is given in a table, agreement between the head datum used to compute the table in FEQUTL (Franz and Melching, 1997) and the head datum given in FEQ when the table is applied will be checked. The head datum applied in the simulation is the head datum as given in FEQ and not in the table. *WRN:15* | nn ITERATIONS REQUESTED FOR SYSTEM SOLUTION BUT ONLY
nn ALLOWED. | More iterations have been requested for the maximum allowed for system solution than have been provided for in ARSIZE.PRM (appendix 3). The parameter MNITER in the INCLUDE file ARSIZE.PRM must be changed, and the program must be recompiled and linked. *WRN:16* | OLD FORM OF TRIB AREA INPUT IS DISCONTINUED. PLEASE
CONVERT OLD FILES TO NEW FORM TO ESTABLISH COMPATIBILITY WITH
VERSION | The input uses the previous input style for Tributary Area Block (section 13.3). This form is no longer supported. Complete details on the current input format are given in section 13.3. *WRN:17* | CONTINUITY ERROR OF ff IN INITIAL CONDITIONS AT NODES:
nn, nn | An error in continuity of flow in the initial conditions has been detected at a junction including the listed flow-path end nodes. If this error is large enough, computational problems may result. The error can be corrected by changing the flow assignments in the backwater computations (section 13.15). *WRN:18* | WS ELEV DIF BTWN NODE nn, aa, & NODE nn, aa, : ff
| A difference in water-surface elevation at the listed flow-path end nodes has been detected. A large difference relative to the depths of water could result in computational problems. The error can be corrected by making appropriate adjustments in the backwater computations. *WRN:19* | Not in use.
| *WRN:20* | Not in use.
| *WRN:21* | Not in use.
| *WRN:22* | FLOW DISCONTINUITY AT CONSTANT FLOW BOUNDARY AT | NODE nn, aa The flow assigned to a branch or a free node in the backwater computations does not match the flow forced at the node by Code = 6. *WRN:23* | Not in use.
| *WRN:24* | NON-CONVERGENCE. TIME STEP WILL BE REDUCED. | The stream-system solution has not converged in the number of iterations allowed. The time step will be reduced according to user instructions, and computations will continue in FEQ. Eventually this process will be terminated either by convergence or by reduction of the time step to a value less than a user-specified minimum value. *WRN:25* | DF = 0.0 IN CHKGEO | The value of the derivative in the single-step, steady-flow computation in CHKGEO is zero. The value is reset to 1.0, and computations continue in FEQ. *WRN:26* | COMPUTATIONAL PROBLEMS LIKELY: CUTOFF ELEVATION = ff
SHOULD BE LESS THAN ELEVATION FOR HEAD = ff | For code 5, type 2 in the Network-Matrix Control Block (section 13.6), the elevation at which the pump is turned on considering conditions at the destination node should be less than the elevation used for computing the head for the diversion of water into the offline reservoir. If the cutoff elevation is higher than the elevation for head, then the pump is turned on while water is diverted into the offline-storage reservoir. If the two elevations are equal, the pumping of the water could cause the water-surface elevation at the destination node to exceed the cutoff elevation. This feedback can result in convergence problems because the pump is turned on and off at successive iterations so that simulation convergence cannot be achieved. *WRN:27* | XKNT= HAS BEEN REPLACED BY PAGE=. PLEASE CHECK RUN
CONTROL BLOCK INPUT DESCRIPTION. | The XKNT option has not been available since version 4.41 of FEQ. The space used by XKNT in the input has now been replaced by a page size specification in the input for the special-output file so that headings can be placed in the file for easier use. Complete details are given in sections 13.1 (Run Control Block description) and 13.9 (Special-Output Locations Block). *WRN:28* | FIRST DEPTH INCREMENT IN TABLE IS LARGE. | The first depth increment in a table to which a bottom slot is to be added is larger than 0.1. NRZERO in FEQUTL (Franz and Melching, 1997) should be checked. Large NRZERO values increase the effect of adding the bottom slot to the cross section. *WRN:29* | BACKW NO LONGER USED. REPLACED BY GEQOPT. | The backwater option has not been available since version 2.0 of FEQ. It has remained in the input for consistency. This option has been replaced by GEQOPT to provide the option of applying different sets of governing equations. Further details are given in section 13.1. *WRN:30* | UNKNOWN OPTION = aa FOR GEQOPT. STDX OPTION ASSUMED.
| An unknown value for the selection of governing equations has been detected for GEQOPT (section 13.1). The STDX option is selected, and computations continue in FEQ. A discussion of the governing equations options is given in section 6.2. *WRN:31* | X-SECTION BELOW RANGE IN XLKTAL | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth less than the minimum depth available in the cross section has been detected in subroutine XLKTAL. This message is not issued if the CUTOFF option (section 13.13) for cross sections has not been applied. *WRN:32* | X-SECTION ABOVE RANGE IN XLKTAL | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth greater than the maximum depth in the cross section has been detected in subroutine XLKTAL. If this warning is issued only a few times and if the resulting maximum depth at the conclusion of the run is less than the maximum, no action is required. However, if the warning is issued many times and the run terminates prematurely or the maximum depth at the conclusion of the run is the same as the maximum depth in the cross section, then the cross section should either be extended by use of the EXT option or additional data should be obtained to further define the cross section and recompute the table with FEQUTL (Franz and Melching, 1997). *WRN:33* | X-SECTION BELOW RANGE IN XLKTnn | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth less than the minimum depth available in the cross section has been detected in subroutine XLKT nn. This message is not issued if the CUTOFF option (section 13.13) for cross sections has not been applied. *WRN:34* | X-SECTION ABOVE RANGE IN XLKTnn | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth greater than the maximum depth in the cross section has been detected in subroutine XLKT nn. If this warning is issued only a few times and if the resulting maximum depth at the conclusion of the run is less than the maximum, no action is required. However, if the warning is issued many times and the run terminates prematurely or the maximum depth at the conclusion of the run is the same as the maximum depth in the cross section, then the cross section should be extended by use of the EXT option or additional data should be obtained to further define the cross section and recompute the table with FEQUTL (Franz and Melching, 1997). *WRN:35* | X-SECTION BELOW RANGE IN LKTQC | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth less than the minimum depth available in the cross section has been detected in subroutine LKTQC. This message is not issued if the CUTOFF option for cross sections has not been applied. The critical flow in type 12 tables (section 11.1.5) is looked up in subroutine LKTQC. *WRN:36* | X-SECTION ABOVE RANGE IN LKTQC | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth greater than the maximum depth in the cross section has been detected in subroutine LKTQC. If this warning is issued only a few times and if the resulting maximum depth at the conclusion of the run is less than the maximum, no action is required. However, if the warning is issued many times and the run terminates prematurely or the maximum depth at the conclusion of the run is the same as the maximum depth in the cross section, then the cross section should be extended by use of the EXT option or additional data should be obtained to further define the cross section and recompute the table with FEQUTL (Franz and Melching, 1997). The critical flow in type 12 tables (section 11.1.5) is looked up in subroutine LKTQC. *WRN:37* | TABLE OVERFLOW AT EXT. NODE = nn ARGUMENT = ff | An argument at a reservoir node exceeding the maximum value in the table has been computed. To prevent exceeding the maximum level in the table, the arithmetic average of the last valid argument and the maximum argument in the table is computed as the argument value to use. If the message persists and computations fail, the table may have to be extended to higher values. In some cases, these values will be false, but they must be supplied in any case. Occasionally, a very large value of storage in the table must be used for determining the solution. If the maximum value resulting from convergence of the iterations is below the maximum of the table, then the solution is valid. However, if the maximum value simulated is higher than the maximum in the table, then some changes must be made in the flows, cross-section hydraulic characteristics, and related input. *WRN:38* | TABLE OVERFLOW AT: nn:nn ARGUMENT = ff | Same as *WRN:37 except that the problem is at a node on a branch. *WRN:39* | DEPTH AT NODE: nn:nn OVERTOPS TABLE# = nn BY ff | The maximum depth in a cross-section table is recalled before any requested extrapolation in the EXT option is done. Cross sections are checked to determine overtopping by more than EXTTOL (section 13.1). EXTTOL should be set so that excessive use of extrapolated information is avoided. *WRN:40* | BRANCH NUMBER = 0 HAS BEEN FOUND MORE THAN ONCE IN
TRIB AREA INPUT. | A branch number of 0 is used in the Tributary Area Block (section 13.3) to reference input of the areas tributary to reservoirs. All reservoirs with tributary area must have the area specified when the branch number is 0. A second branch number of 0 has been detected. An error may result in the branch number sequence. *WRN:41* | X-SECTION BELOW RANGE IN LKTK | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth less than the minimum depth available in the cross section has been detected in subroutine LKTK. This message is not issued if the CUTOFF option for cross sections has not been applied. The conveyance in type 12 tables (section 11.1.5) is looked up in subroutine LKTK. *WRN:42* | X-SECTION ABOVE RANGE IN LKTK | TABLE NUMBER = nn STATION NUMBER = ff TIME = ff DEPTH = ff A depth greater than the maximum depth in the cross section has been detected in subroutine LKTK. If this warning is issued only a few times and if the resulting maximum depth at the conclusion of the run is less than the maximum, no action is required. However, if the warning is issued many times and the run terminates prematurely or the maximum depth at the conclusion of the run is the same as the maximum depth in the cross section, then the cross section should be extended by use of the EXT option or additional data should be obtained to further define the cross section and recompute the table with FEQUTL (Franz and Melching, 1997). The conveyance in type 12 tables (section 11.1.5) is looked up in subroutine LKTK. *WRN:43* | FLOW > MAXFLOW IN TWO-D TABLE# = nn FLOW = ff
MAXFLOW = ff | A flow argument greater than the tabulated maximum has been detected in a table with an argument of flow. The maximum value from the table will be used, and computations will continue in FEQ, if possible. If this message is issued infrequently and if none of the output values appear to be limited by the maximum flow in the table, then this warning probably results because of an intermediate value of the solution. If, however, this message appears frequently, it is probable that the results have been affected by the flow limitation in the table. Therefore, the table must be recomputed to a higher value of flow. *WRN:44* | HDN > MAXHDN IN TWO-D TABLE# = nn HDN = ff MAXHDN =
ff | A table has been accessed with a value of downstream piezometric head that is greater than the maximum tabulated value. The maximum table value will be used, and computations will continue in FEQ if possible. If this message is issued frequently, then it is likely that the limitation on table extent affected the results. If it is issued infrequently, it is likely a transient problem detected in the search for the solution at some point. The output results should be checked to determine whether the downstream head for this table was limited to the tabulated maximum. If there is a limitation or the message is issued frequently, then the table must be recomputed to a higher value. *WRN:45* | START TIME LEADS TIME IN GETIC FILE BY ff SECONDS. | The start time of the run differs from the time at which the information in the Get-Initial-Conditions file (section 13.1) was written. Computations will continue, but the times do not match. If the time given is positive, then there is a gap between the time at which the initial conditions were written and the time when the run starts. Otherwise, an overlap of the simulated periods results between the Get-Initial-Conditions file and the current run. *WRN:46* | TYPE 3 TABLE INTEGRAL RELATIVE ERROR >.02 TABLE#=
nn ARGUMENT= ff | COMPUTED INTEGRAL USED The integral for type 3 tables is computed in version 6.6 or later of FEQ, and the computed value is compared to the value specified in the table. If the difference is greater than 0.02, this warning is issued. In any case, the computed value of the integral and not the tabulated value of the integral is used in FEQ. *WRN:47* | NODE= nn < 0 INVALID. FEQ TAKES ABSOLUTE VALUE.
| Negative node numbers are not permitted in the Network-Matrix Control Block (section 13.6) in Version 7.0 and later versions of FEQ. The absolute value of the node is taken, and the processing of the model continues. *WRN:48* | FOR NODE= aa INPUT SIGN DISAGREES WITH INTERNAL SIGN.
INTERNAL SIGN USED. | The correct node sign is assigned to all free nodes in Version 7.0 and later versions of FEQ. The node sign input in the Free-Node Initial Conditions Block (section 13.14) is still retained and is checked. However, the internal sign based on the context of the free node in the Network-Matrix Control Block (section 13.6) is applied. *WRN:49* | TWO-D TABLE OVERFLOWS HAVE OCCURRED | During the course of computations, a lookup in a 2-D table that goes above the maximum arguments will sometimes be attempted. This may just be an intermediate result in the iterative solution (the final solution is below the maximum argument values). However, in some cases, the tables are not large enough to contain the flows of interest. It is often difficult to distinguish the two cases from the warning messages issued as the computations progress. Therefore, at the conclusion of computations, the 2-D tables are checked against the extreme values computed. Two-dimensional tables with an inadequate argument range are listed in a table following this message. If the table is of type 6 or 13, the overflow is with respect to head; and if the table is of type 14, the overflow is with respect to flow and perhaps head. The entries in the warning table are filled as appropriate. When a 2-D table argument is exceeded, the maximum value in the table is used in the computations. No extrapolation of values is done. The table overflow can seriously distort computational results because table overflows yield results similar to obstructions to the flow. Thus, the water-surface elevations upstream from the location of a structure for which the table values are exceeded become too large. In general, the tabled values should be extended until this message is no longer issued. *WRN:50* | FLOW DIRECTION AND HEAD DIFFERENCE INCONSISTENT.
ADJUSTING UPSTREAM WATER LEVEL AND ATTEMPTING TO CONTINUE. | This message may be issued during computation of the initial conditions at a control structure represented with the code 5, type 6 option in the Network-Matrix Control Block (section 13.6). Nothing needs to be done if the computations converge. If the computations do not converge, then the reasons for the discrepancy between head difference and flow direction must be resolved. Perhaps the flow as assigned is in the wrong direction, or perhaps the control structure is reversed. *WRN:51* | YE 2(I) <=0.0 IN CMPCOR AT EXNODE = aa | This message indicates that the standard method for correction of an estimated depth at the flow-path end node resulted in a nonpositive corrected depth. This is most likely an intermediate result in the solution process. However, if the solution does not converge, then the flow-path end node given and neighboring nodes in the model should be reviewed as potential sources for the cause of the nonconvergence. |