These warning and error messages were added in SWMM 18.104.22.168 to 5.0.016 to trap questionable raingage, link and node data. Correcting these errors does make a better model . The list shown below has the major new warnings and errors and help on interpreting the messages.
WARNING 01: wet weather time step reduced to recording interval for Rain Gage
Explanation: The user selected hydrology time step is automatically reduced by the engine to match the rain gage interval. The smallest rainfall interval among all of the gages will be used during the simulation.
WARNING 02: maximum depth increased for Node
Explanation: The rim elevation of a node has to be at least equal to the crown elevation of the highest connecting link to the node. The maximum depth of the node is increased to match the highest crown elevation.
WARNING 03: negative offset ignored for Link
Explanation: Negative Offsets are set to offsets of 0.0
WARNING 04: minimum elevation drop used for Conduit
Explanation: If the elevation across the link length is less than 0.001 feet then the elevation drop is set to 0.001 feet (internal units).
WARNING 05: minimum slope used for Conduit
Explanation: If the link slope is less than the user defined minimum slope then the engine will set the slope of the link to the minimum slope.
WARNING 06: dry weather time step increased to the wet weather time step
Explanation: The Dry hydrology time step cannot be less than the wet weather hydrology time step.
WARNING 07: routing time step reduced to the wet weather time step
Explanation: Routing step set to the wet hydrology time step.
ERROR 112: elevation drop exceeds length for Conduit
Explanation: The drop across the conduit cannot exceed the conduit length. It indicates short conduits that likely have improper offset elevations or incorrectly estimated lengths based on the large offsets of the conduit.
ERROR 134: Node has illegal DUMMY link connections.
Explanation: This means either the model has more than one Ideal Pump connecting the same upstream and downstream nodes or a dummy link with more than one link exiting its upstream node.
ERROR 151: a Unit Hydrograph in set has invalid time base.
Explanation: The value of T*K or the Time Base for a RDII Unit Hydrograph has a value less than the rain gage interval. The fundamental time unit for Unit Hydrographs is the rain gage time interval.
ERROR 157: inconsistent rainfall format for Rain Gage
Explanation: Two or more gages using the same time series have different rainfall types in the rain gage definition. For example, intensity and volume.
ERROR 159: inconsistent time interval for Rain Gage
Explanation: The rain gage user defined rainfall interval does not match the actual rainfall time series.
ERROR 173: Time Series has its data out of sequence
Explanation: A time series has either the same time value for consecutive intervals or the time values are out of numerical order.