There is not enough physical memory in the computer to analyze the study area.

The internal solver for Kinematic Wave routing failed to converge for the specified link at some stage of the simulation.

The system could not open its Ordinary Differential Equation solver.

A valid time step for runoff or flow routing calculations (i.e., a number greater than 0) could not be computed at some stage of the simulation.

The name of the element identified as the outlet of a Subcatchment belongs to both a node and a Subcatchment in the project's data base.

The properties entered for an aquifer object were either invalid numbers or were inconsistent with one another (e.g., the soil field capacity was higher than the porosity).

The ground elevation assigned to a Subcatchment’s groundwater parameters cannot be below the initial water table elevation of the aquifer object used by the Subcatchment.

Conduits cannot have zero or negative lengths.

Conduits cannot have zero or negative roughness values.

Under Steady or Kinematic Wave routing, all conduits must have positive slopes. This can usually be corrected by reversing the inlet and outlet nodes of the conduit (i.e., right click on the conduit and select Reverse from the popup menu that appears). Adverse slopes are permitted under Dynamic Wave routing.

Cross section geometry was never defined for the specified link.

Either an invalid shape or invalid set of dimensions was specified for a link's cross section.

Either no pump curve or an invalid type of curve was specified for a pump.

The Steady and Kinematic Wave flow routing methods cannot be applied to systems where a cyclic loop exists (i.e., a directed path along a set of links that begins and ends at the same node). Most often the cyclic nature of the loop can be eliminated by reversing the direction of one of its links (i.e., switching the inlet and outlet nodes of the link). The names of the links that form the loop will be listed following this message.

Under Steady and Kinematic Wave flow routing, a junction node can have only a single outlet link.

Only a single conduit with a DUMMY cross-section or Ideal-type pump can be directed out of a node; a node with an outgoing Dummy conduit or Ideal pump cannot have all of its incoming links be Dummy conduits and Ideal pumps; a Dummy conduit cannot have its upstream end connected to a storage node.

Flow divider nodes must have two outlet links connected to them.

The link specified as being the one carrying the diverted flow from a flow divider node was defined with a different inlet node.

The parameters of a Weir-type divider node either are non-positive numbers or are inconsistent (i.e., the value of the discharge coefficient times the weir height raised to the 3/2 power must be greater than the minimum flow parameter).

Self-explanatory.

Under Steady or Kinematic Wave flow routing, orifices, weirs, and outlet links can only be used as outflow links from storage nodes.

An outfall node is only permitted to have one link attached to it.

An orifice must have either a CIRCULAR or RECT_CLOSED shape, while a weir must have either a RECT_OPEN, TRAPEZOIDAL, or TRIANGULAR shape.

Under Dynamic Wave flow routing, there must be at least one node designated as an outfall.

The time base of a Unit Hydrograph cannot be negative and if positive, must not be less than the recording interval for its rain gage.

The response ratios for a set of Unit Hydrographs (the short-, medium-, and longterm response hydrographs) must be between 0 and 1.0 and cannot add up to a value greater than 1.0

The sewer area contributing RDII inflow to a node cannot be a negative number.

If two Rain Gages use files for their data sources and have the same Station IDs then they must also use the same data files.

If two or more rain gages use the same Time Series for their rainfall data then they must all use the same data format (intensity, volume, or cumulative volume).

A rainfall Time Series associated with a Rain Gage cannot be used by another object that is not also a Rain Gage.

The recording time interval specified for the rain gage is greater than the smallest time interval between values in the Time Series used by the gage.

An example would be where the removal of pollutant 1 is defined as a function of the removal of pollutant 2 while the removal of pollutant 2 is defined as a function of the removal of pollutant 1.

The X-values of a curve object must be entered in increasing order.

The time (or date/time) values of a time series must be entered in sequential order.

The ATI Weight or Negative Melt Ratio parameters are not between 0 and 1 or the site latitude is not between -60 and +60 degrees.

A snow pack’s minimum melt coefficient is greater than its maximum coefficient; the fractions of free water capacity or impervious plowable area are not between 0 and 1; or the snow removal fractions sum to more than 1.0.

A named LID control has layers defined for it but its LID type was never specified.

A required design layer is missing for the specified LID control.

An invalid value was supplied for an LID control's design parameter.

The area of the LID controls placed within the Subcatchment is greater than that of the Subcatchment itself.

This message appears when one or more input file parsing errors (the 200-series errors) occur.

A line in the input file cannot exceed 1024 characters.

Not enough data items were supplied on a line of the input file.

An unrecognized keyword was encountered when parsing a line of the input file.

An ID name used for an object was already assigned to an object of the same category.

A reference was made to an object that was never defined. An example would be if node 123 were designated as the outlet point of a Subcatchment, yet no such node was ever defined in the study area.

Either a string value was encountered where a numerical value was expected or an invalid number (e.g., a negative value) was supplied.

An invalid format for a date or time was encountered. Dates must be entered as month/day/year and times as either decimal hours or as hour:minute:second.

Errors of this nature can occur when the format for writing control rules is not followed correctly (see Section C.3).

A GR line with Station-Elevation data was encountered in the [TRANSECTS] section of the input file after an NC line but before any X1 line that contains the transect’s ID name.

The station distances specified for the transect of an irregular cross section must be in increasing numerical order starting from the left bank.

A transect for an irregular cross section must have at least 2 stations defined for it.

A transect cannot have more than 1500 stations defined for it.

No Manning’s N was specified for a transect (i.e., there was no NC line in the [TRANSECTS] section of the input file.

The distance values specified for either the left or right overbank locations of a transect do not match any of the distances listed for the transect's stations.

All of the stations for a transect were assigned the same elevation.

A treatment function supplied for a pollutant at a specific node is either not a correctly formed mathematical expression or refers to unknown pollutants, process variables, or math functions.

The input, report, and binary output files specified on the command line cannot have the same names.

The input file either does not exist or cannot be opened (e.g., it might be in use by another program).

The report file cannot be opened (e.g., it might reside in a directory to which the user does not have write privileges).

The binary output file cannot be opened (e.g., it might reside in a directory to which the user does not have write privileges).

There was an error in trying to write results to the binary output file (e.g., the disk might be full or the file size exceeds the limit imposed by the operating system).

The command line version of SWMM could not read results saved to the binary output file when writing results to the report file.

SWMM could not open the temporary file it uses to collate data together from external rainfall files.

SWMM could not open the specified rainfall interface file, possibly because it does not exist or because the user does not have write privileges to its directory.

An external rainfall data file could not be opened, most likely because it does not exist.

An external user-prepared rainfall data file must have its entries appear in chronological order. The first out-of-order entry will be listed.

SWMM could not recognize the format used for a designated rainfall data file.

SWMM was trying to read data from a designated rainfall interface file with the wrong format (i.e., it may have been created for some other project or actually be some other type of file).

This message occurs when a project wants to use a previously saved rainfall interface file, but cannot find any data for one of its rain gages in the interface file. It can also occur if the gage uses data from a user-prepared rainfall file and the station id entered for the gage cannot be found in the file.

A runoff interface file could not be opened, possibly because it does not exist or because the user does not have write privileges to its directory.

SWMM was trying to read data from a designated runoff interface file with the wrong format (i.e., it may have been created for some other project or actually be some other type of file).

This error can occur when a previously saved runoff interface file is being used in a simulation with a longer duration than the one that created the interface file.

A format error was encountered while trying to read data from a previously saved runoff interface file.

A hot start interface file could not be opened, possibly because it does not exist or because the user does not have write privileges to its directory.

SWMM was trying to read data from a designated hot start interface file with the wrong format (i.e., it may have been created for some other project or actually be some other type of file).

A format error was encountered while trying to read data from a previously saved hot start interface file.

This error occurs when the user specifies that evaporation or wind speed data will be read from an external climate file, but no name is supplied for the file.

An external climate data file could not be opened, most likely because it does not exist.

SWMM was trying to read data from an external climate file with the wrong format.

The specified external climate does not include data for the period of time being simulated.

SWMM could not open the temporary file it uses to store RDII flow data.

An RDII interface file could not be opened, possibly because it does not exist or because the user does not have write privileges to its directory.

SWMM was trying to read data from a designated RDII interface file with the wrong format (i.e., it may have been created for some other project or actually be some other type of file).

A routing interface file could not be opened, possibly because it does not exist or because the user does not have write privileges to its directory.

SWMM was trying to read data from a designated routing interface file with the wrong format (i.e., it may have been created for some other project or actually be some other type of file).

The names of pollutants found in a designated routing interface file do not match the names used in the current project.

.In cases where a run uses one routing interface file to provide inflows for a set of locations and another to save outflow results, the two files cannot both have the same name.

The external file used to provide data for the named time series could not be opened, most likely because it does not exist.

The wet weather time step was automatically reduced so that no period with rainfall would be skipped during a simulation.

The maximum depth for the node was automatically increased to match the top of the highest connecting conduit.

The link’s stipulated offset was below the connecting node's invert so its actual offset was set to 0.

The elevation drop between the end nodes of the conduit was below 0.001 ft (0.00035 m) so the latter value was used instead to calculate its slope.

The conduit's computed slope was below the user-specified Minimum Conduit Slope so the latter value was used instead.

The user-specified time step for computing runoff during dry weather periods was lower than that set for wet weather periods and was automatically increased to the wet weather value.

The user-specified time step for flow routing was larger than the wet weather runoff time step and was automatically reduced to the runoff time step to prevent loss of accuracy.

The elevation drop across the ends of a conduit exceeds its length. The program computes the conduit's slope as the elevation drop divided by the length instead of using the more accurate right triangle method. The user should check for errors in the length and in both the invert elevations and offsets at the conduit's upstream and downstream nodes.

The smallest time interval between entries in the precipitation time series used by the rain gage is greater than the recording time interval specified for the gage. If this was not actually intended then what appear to be continuous periods of rainfall in the time series will instead be read with time gaps in between them.

The height of the opening on an orifice, weir, or outlet is below the invert elevation of its downstream node. Users should check to see if the regulator's offset height or the downstream node's invert elevation is in error.

The premise of a control is comparing two different types of attributes to one another (for example, conduit flow and junction water depth). The external file used to provide data for the named time series has one or more lines with the wrong format.