Sunday, August 16, 2009

Suggestion for Entering Population DWF Data at a Node

I (and a few others) think a welcome change to the DWF dialog in SWMM 5 would be the addition of another scale factor to modify the average flow field. The purpose of the scale factor would be to allow the users to enter the DWF contributing population * the various DWF patterns * the scale factor (in units of cfs/person or l/s/person) in the Inflows dialog. Some users of SWMM 5 prefer to use population directly in the GUI rather than doing this calculation externally and entering either the flow in cfs or l/s. An example of why this would be useful is a future conditions model in which the population either increases or decreases in the catchment.


Here's a revised emoji-laden table reflecting your suggestion for a welcome change in the Dry Weather Flow (DWF) dialog in SWMM 5, along with its implementation in InfoSWMM and ICM SWMM:

Topic πŸ“˜SWMM5 🌊InfoSWMM πŸ”„ICM SWMM πŸŒͺ️Emoji Illustration 🎨
Proposed DWF Scale Factor 🎚️Addition of a scale factor to modify the average flow field, allowing users to input DWF contributing population, DWF patterns, and scale factor (in units of cfs/person or l/s/person) directly in the Inflows dialog.(Potential implementation or extension in InfoSWMM based on user preference)(Potential implementation or extension in ICM SWMM based on user preference)🎚️πŸ‘₯πŸ’§
Usage Ease πŸ€—Enabling direct population input in the GUI, eliminating the need for external calculations, thereby facilitating more straightforward flow entries in cfs or l/s.(Assumed similar ease of use enhancement in InfoSWMM if implemented)(Assumed similar ease of use enhancement in ICM SWMM if implemented)πŸ€—➡️πŸ’»
Future Conditions Modeling 🌐Catering to models depicting population increase or decrease in a catchment, aiding in more accurate future condition analyses.(Potential facilitation of future conditions modeling in InfoSWMM if implemented)(Potential facilitation of future conditions modeling in ICM SWMM if implemented)🌐πŸ‘₯πŸ”„

This table encapsulates the proposed change in SWMM 5 concerning the Dry Weather Flow (DWF) dialog, allowing for a new scale factor to alter the average flow field. The table also leaves room for similar implementations or extensions in InfoSWMM and ICM SWMM, provided that these platforms decide to adopt this user-friendly feature, making it easier to handle population-based flow calculations directly within the software's GUI.


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Friday, August 14, 2009

New Warning Messages in SWMM 5.0.014 to 5.0.016

These warning and error messages were added in SWMM 5.0.0.14 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.

The Goal of SWMM5 Input Files

 πŸŒŸ SWMM5 (Storm Water Management Model 5) is a widely used urban hydrology and hydraulic modeling software developed by the United States E...